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CHAPTER 1

INTRODUCTION

1.1 GENERAL

Buildings & houses are one of the oldest construction activities of human beings the

construction technology has the beginning from primitive construction technology to

the present concept of modern house building. The present construction methodology

for buildings calls for the best aesthetic look, high quality & fast construction, cost

effective & innovative touch.

1.2 PEB IN INDIA

India has the second fastest growing economy in the world and a lot of it, is attributed

to its construction industry which figures just next to agriculture in its economic

contribution to the nation. In its steadfast development, the construction industry has

discovered, invented and developed a number of technologies, systems and products,

one of them being the concept of Pre-engineered Buildings (PEB s). As opposed to

being on-site fabricated, PEB s are delivered as a complete finished product to the site

from a single supplier with a basic structural steel framework with attached factory

finished cladding and roofing components. The structure is erected on the site by bolting

the various building components together as per specifications. PEB s are developed

using potential design software. The onset of technological advancement enabling 3d

modelling and detailing of the proposed structure and coordination has revolutionized

Conventional building construction. Pre-Engineered

PEB has boon to Multi storey Buildings in India. Decking sheets with concrete over can

be used as roofing and raised to any extent above 40 meters. These have a tracking rate

of 80% in western countries. PEB Buildings is the future for India. Most of the Indian

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business community is just started to realize the benefits of PEB .Where you have been

building with concrete for as long as anyone can remember, it is difficult to change.

However India’s most progressive companies are seeing the benefits of PEB

Although PEB systems are extensively used in industrial and many other non–

residential constructions worldwide it is relatively a new concept in India .these concept

were introduced to the Indian markets lately in the late 1990’s with the opening up of

the economy and a number of multi nationals setting up their projects .the market

potential of PEB is 1.2 million tonnes per annum .the current pre – engineered steel

building manufacturing capacity is 0.35 tonnes per annum. The industry is growing at

the compound rate of 25 to 35 % [16]

1.3 SCOPE AND OBJECTIVES OF THE PROJECT

1.3.1 SCOPE OF THE PROJECT

1. Steel buildings in which excess steel is avoided by tapering the sections which in

turn is more economical and aesthetic than conventional steel building

2. Tapering is done as per Bending Moment requirements as to avoid excess of steel.

3. Components are manufactured in factory and assembled on site.

4. Larger plate dimensions are used in areas of higher load effects in case of large

spans and high rise industrial building such as aircraft hangars, warehouse etc.

5. An efficiently designed Pre-Engineered Building can be lighter that the

conventional steel buildings by up to 30% and thus economical

PEB concept has been very successful and well established in North America, Australia

and is presently expanding in U.K and European countries. PEB construction is 30 to

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40% faster than masonry construction. PEB buildings provide good insulation effect

and would be highly suitable for a tropical country like India.

The pre-engineered building calls for very fast construction of buildings and with good

aesthetic looks and quality construction. Pre-engineered Buildings can be used

extensively for construction of industrial and residential buildings.

1.3.2 OBJECTIVE OF THE PROJECT

The following are objective of the project and a detailed report on design and analysis

of the pre-engineered building is discussed in the upcoming chapters.

1. To Study Pre-Engineered Building.

2. To Prepare a Model of P.E.B.

3. To Analyze Structure Using STAAD Pro.

4. To Design Sections, Connections etc.

5. To Study The Effect Of P.E.B. For Following Issues:

i. To Reduce Complexity On Site.

ii. To Achieve Accuracy.

iii. Speed of Work.

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CHAPTER 2

LITERATURE REVIEW

2.1 GENERAL

In this chapter the literature review of pre-engineered building is carried out from

various books, reference, journals, and from several websites .the brief discussion of

the pre-engineered building is presented below in this project

2.1.1 Syed Firoz, Sarath,Chandra Kumar et.al (2012) observed that, The pre-

engineered steel building system construction has great advantages to the single storey

buildings, practical and efficient alternative to conventional buildings, the System

representing one central model within multiple disciplines. Pre- engineered building

creates and maintains in real time multidimensional, data rich views through a project

support is currently being implemented by STAAD pro software packages for design

and engineering [16]. Choosing steel to design a Pre-engineered steel structures

building is to choose a material which offers low cost, strength, durability, design

flexibility, adaptability and recyclability. Steel is the basic material that is used in the

Materials that are used for Pre- engineered steel building. It negates from regional

sources. It also means choosing reliable industrial products which come in a huge range

of shapes and colours; it means rapid site installation and less energy consumption. It

means choosing to commit to the principles of sustainability. Infinitely recyclable, steel

is the material that reflects the imperatives of sustainable development.

A tall steel building is not more in the total number of tall steel structures that are built

around the world. A large steel structures being built are only single storey buildings

for industrial purpose. Secondary structural members span the distance between the

primary building frames of metal building systems. They play a complex role that

extends beyond supporting roof and wall covering and carrying exterior loads to main

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frames. Secondary structural, as these members are sometimes called, may serve as

flange bracing for primary framing and may function as a part of the building’s lateral

load–resisting system. Roof secondary members, known as purlins, often form an

essential part of horizontal roof diaphragms; wall secondary members, known as girts,

are frequently found in wall bracing assemblies. The majority of steel structures being

built are only low-rise buildings, which are generally of one storey only. Industrial

buildings, a sub- set of low-rise buildings are normally used for steel plants, automobile

industries, light, utility and process industries, thermal power stations, warehouses,

assembly plants, storage, garages, small scale industries, etc. These buildings require

large column free areas. Hence interior columns, walls and partitions are often

eliminated or kept to a minimum. Most of these buildings may require adequate

headroom for use of an overhead traveling crane. A third type of secondary

framing,[16]] known by the names of eave strut, eave purlin, or eave girt, acts as part

purlin and part girt—its top flange supports roof panels, its web, wall siding. Girts,

purlins, and eave struts exhibit similar structural behaviour. Since most secondary

members normally encountered in metal building systems are made of cold- formed

steel, our discussion starts with some relevant issues in design of cold-formed steel

structures.

2.1.2 Aijaz Ahmad Zende 1, Prof. A. V. Kulkarni, et.al (Jan. - Feb. 2013) observes

that even though PEB structures provides clear span, it weighs lesser than that of

Conventional Buildings. Infinitely recyclable, steel is the material that reflects the

imperatives of sustainable development. For longer span structures, Conventional

buildings are not suitable with clear spans. Pre-engineered building are the best solution

for longer span structures without any interior column in between as seen in this present

work, an industrial structure has been designed for 88m. With the advent of

computerization, the design possibilities became almost limitless. Saving of material on

low stress area of the primary framing members makes Pre- engineered buildings more

economical than Conventional steel buildings especially for low rise buildings spanning

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up to 90.0 meters with eave heights up to 30.0 meters. PEB structures are found to be

costly as compared to Conventional structures in case of smaller span structures. To

Conclude ―Pre-Engineered Building Construction gives the end users a much more

economical and better solution for long span structures where large column free areas

are needed [6].

2.1.3 C. M. Meera (June 2013) observes that Pre-Engineered Building (PEB) concept

is a new conception of single storey industrial building construction. This methodology

is versatile not only due to its quality pre-designing and prefabrication, but also due to

its light weight and economical construction. The concept includes the technique of

providing the best possible section according to the optimum requirement. This concept

has many advantages over the Conventional Steel Building (CSB) concept of buildings

with roof truss. This paper is a comparative study of PEB concept and CSB concept.

Pre-Engineered Building concept have wide applications including warehouses,

factories, offices, workshops, gas stations, showrooms, vehicle parking sheds, aircraft

hangars, metro stations, schools, recreational buildings, indoor stadium roofs, outdoor

stadium canopies, railway platform shelters, bridges, auditoriums, etc, explicitly as in.

PEB structures can also be designed as re-locatable structures. Steel is a material which

has high strength per unit mass. Hence it is used in construction of structures with large

column-free space. Most of the Industrial Structures require this criterion. An Industrial

Warehouse is a storage building and is usually characterized as single storey steel

structures with or without mezzanine floors. The enclosures of these structures may be

brick masonry, concrete walls or GI sheet coverings. The walls are generally non-

bearing but sufficiently strong enough to withstand lateral forces caused by wind or

earthquake. The designing of industrial warehouse includes designing of the structural

elements including principal rafter or roof truss, column and column base, purlins, sag

rods, t gantry girder, bracings, etc. A combination of standard hot-rolled sections, cold-

formed sections, profiled sheets, steel rods, etc. are used for the construction of

industrial steel structures. Industrial buildings can be categorized as Pre-Engineered

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Buildings (PEB) and Conventional Steel Buildings (CSB), according to the design

concepts. The paper starts with the discussion of methods adopted in the study.

Introduction to PEB systems and CSB systems are then described followed by the

details of case study. Loads and the load combinations adopted for carrying out the

analysis of the structure is well defined in the further portions. A section depicting the

importance of the software used and the software procedure followed is included. Final

portion explains the results obtained from the software analysis of the case study and

the inferences from the literature studies. The paper aims at developing a perception of

The design concepts of PEB structures and its advantages over CSB structures.

2.1.4 Jatin D. Thaka r, 2 Prof. P.G. Patel observes that Pre-engineered building are

steel building wherein the framing members and other components are fully fabricated

in the factory after designing and brought to the site for assembly, mainly by nut-bolts,

thereby resulting into a steel structure of high quality and precision. In conventional

steel construction, we have site welding involved, which is not the case in P.E.B using

nut-bolt mechanism. These structures use hot rolled tapered sections for primary

framing and cold rolled sections for secondary framing as per the internal stress

requirements, thus reducing wastage of steel and the self- weight of the structure and

hence lighter foundations. International codes are referred in their design as per the

MBMA (Metal Building Manufacture Association) Standards which are more flexible

Allowing the use of built - up sections of minimum 3.5 mm thickness against 6 mm as

minimum criteria in conventional steel sections .There is use of steel of high strength

(345MPa) which prominently speaks about greater strength with judicious use of steel

as a result of tapered profile. The tapered section concept was first adopted in U.S.A

keeping in mind the bending moment diagram. At locations of high bending moment

values, greater depth is used while less moment encouraged the use of lesser depths.

Further unlike the conventional steel sections, where Moment of inertia (I) remains

constant, it is not so in case of P.E.B due to varying depths.

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2.1.5 G. Sai Kiran, A. Kailasa Rao, R. Pradeep Kumar (Aug 2014) observes that, in

recent years, the introduction of Pre Engineered Building (PEB) concept in the design

of structures has helped in optimizing design. The adoptability of PEB in the place of

Conventional Steel Building (CSB) design concept resulted in many advantages,

including economy and easier fabrication. In this study, an industrial structure (Ware

House) is analysed and designed according to the Indian standards, IS 8001984, IS 800-

2007 and also by referring MBMA-96 and AISC-89. In this study, a structure with

length 187m,width 40m,with clear height 8m and having Slope 1:10,isconsidered to

carry out analysis& design for 2D frames (End frame, frame without crane and frame

with 3 module cranes). The economy of the structure is discussed in terms of its weight

comparison, between Indian codes (IS800-1984, IS800-2007) & American code

(MBMA-96), & between Indian codes (IS800-1984, IS800-2007).

2.1.6 S.D. Charkha and Latesh S (June 2014) observes that, Using of PEB instead of

CSB may be reducing the steel quantity. Reduction in the steel quantity definitely

reducing the dead load. Reduction in the dead load reducing the size of Foundation.

Using of PEB increase the Aesthetic view of structure.

2.1.7 U. D. Dabhade1, N.A.Hedaoo2, Dr. L. M. Gupta3 and Dr. G. N (2009)

observes that, the time savings of 55.3% is achieved due to use of steel framed

composite floor construction rather than precast framed with precast concrete floor and

14.3% time than that of steel framed with precast concrete slab. The construction of

steel framed composite floor building saves time, which leads to an overall savings in

net cost. The direct cost required for steel framed with composite floor is 23.10%, higher

than precast frame with precast concrete floor and only 0.52% higher than steel framed

with precast concrete floor. Considering time related savings, the net cost required for

steel framed with composite floor is 12.99%, more than precast frame with precast

concrete floor and 2.32% less than steel frame with precast floor. The steel framed with

precast concrete floor saves 35.83% construction time than precast frame with precast

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concrete floor, which required extra 22.70% of direct cost and 14.96% of net cost.

However, study is restricted to structural frame only. If other items are also considered

in the study like excavation work, finishing items, services, cladding etc.

2.2 CLASSIFICATION OF BUILDINGS

A healthy trend in the form of growth in demand for construction works in residential,

Commercial, Institutional, industrial and infrastructure sectors are being seen over the

past decade. Modern Structures are much more complex and sophisticated as compared

to earlier period. One of the major changes which are being felt by all is that the present

structures are taller and thinner. Modern day requirement of structures is that these

should be lighter yet not compromising on functionality. Civil engineering construction

has seen a continual economic competition between steel, concrete and other

construction materials.

2.2.1 Reinforced Cement Concrete Buildings

Reinforced concrete is concrete in which reinforcing bars have been integrated to

improve one or more properties of the concrete. For many years, it has been utilized as

an economical construction material in one form or another. A large part of its

worldwide appeal is that the basic constituent materials cement, sand, aggregate, water,

and reinforcing bars are widely available and that it is possible to construct a structure

using local sources of labour and materials.

2.2.2 Timber Buildings

Timber Buildings are more feasible in areas where wood materials are easily accessible,

wood construction is often considered to be the cheapest and best approach for small

housing structures. Wooden or timber buildings are constructed in western countries

where temperatures are too low. In wooden buildings the members such as beams,

columns and roofs are made of wood. The wooden buildings may be in thatched,

gypsum and ply wood sheeting etc.

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2.2.3 Steel Buildings

Steel is the material of choice for design because it is inherently ductile and flexible. It

flexes under extreme loads rather than crushing and crumbling. Structural steel s low

cost, strength, durability, design flexibility, adaptability and recyclability continue to

make it the material of choice in building construction. Today s structural steel framing

is bringing grace, art and function together in almost limitless ways and is offering new

solutions and opportunities to create challenging structures, which were once thought

impossible. Steel structures have reserve strength. Simple stick design in the steel

framings allows construction to proceed rapidly from the start of erection.

2.2.4 Conventional Steel Buildings

Conventional Steel buildings are consultant and conservative. The Structural members

are hot rolled and are used in conventional buildings. The materials are produced or

manufactured in the plant and are shifted to the site. The raw materials are processed

in the site for the desired form and erected. The modifications can be done during

erection by cut and weld process. Truss systems are used in conventional system.

2.2.5 Pre-engineered Steel Buildings

Pre-engineered Steel Buildings are manufactured or Produced in the plant itself. The

manufacturing of structural members is done on customer requirements. The detailed

structural members are designed for their respective location and are numbered, which

cannot be altered; because members are manufactured with respect to design features.

These components are made in modular or completely knocked condition for

transportation. These materials are transported to the customer site and are erected.

Welding and cutting process are not performed at the customer site. No manufacturing

process takes place at the customer site. [6]

In the Design Process the frame data is assembled based on number of frame members,

number of joints, number of degrees of freedom, the conditions of restraint and the

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elastic properties of the members. Based on this, the data is stored and member section

properties are computed.

• Allowable stress design method is used as per the AISC specifications.

• Unless otherwise specified, the deflections will go to MBMA, AISC criteria and

standard industry practices.

• In Primary Framing Moment resisting frames with pinned or fixed bases.

• Using IS 875 Part 3 design wind loads are calculated and Using IS 1893- 2002

seismic loadings are calculated.

• In Secondary Framing Cold formed Z sections or C sections for purlins or girts

designed as continuous beams spanning over rafters and columns with laps.

Fig.2.1 Schematic Differentiation between Pre-Engineered Buildings

Vs. Conventional Buildings

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2.2.6 Pre-engineered Buildings vs. conventional buildings [16]

Property Pre-engineered Steel

buildings

Conventional Steel buildings

Structural

weight

Pre-engineered

buildings are on the

average 30% lighter

because of the efficient

use of steel. Primary

framing members are

tapered built up

section. With the large

depths in areas of

higher stress.

Secondary members

are light weight roll

formed z or c shaped

members

Primary steel members are

selected hot rolled t sections.

Which are, in many segments

of the members heavier than

what is actually required by

design? Members have

constant cross section

regardless of the varying

magnitude of the local stresses

along the member length.

Secondary members are

selected from standard hot

rolled sections which are much

heavier

Design Quick and efficient: since

PEB s are mainly formed by

standard sections and

connections design, time is

Each conventional steel structure is

designed from scratch with fewer

design aids available to the engineer.

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significantly reduced. Basic

design based on international

design codes are used over

and over.

Specialized computer

analysis design programs

optimize material required.

Drafting is also computerized

using standard details to

minimize the use of project

custom details.

substantial engineering and detailing

work is required from the very basic

is required by the consultant with

fewer design aids.

Delivery Average 6 to 8 weeks Average 20 to 26 weeks

Foundation Simple design, easy to

construct and light weight.

Extensive, heavy foundation

required.

Erection

Since the connection of

compounds is standard the

learning curve of erection for

each subsequent project is

faster.

The connections are normally

complicated and differ from project

to project resulting tin increasing the

time for erection of the buildings.

Erection Cost

And time

Both costs and time of

erection are accurately known

based upon extensive

Typically, conventional steel

buildings are 20% more expensive

than PEB in most of the cases, the

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experience with similar

buildings.

The erection process is faster

and much easier with very

less requirement for

equipment.

erection costs and time are not

estimated accurately.

Erection process is slow and

extensive field labour is required.

Heavy equipment is also needed.

Seismic

Resistance

The low weight flexible

frames offer higher resistance

to seismic forces.

Rigid heavy frames do not perform

well in seismic zones.

Over

All Price

Price per square meter may be

as

Low as by 30 % than the

conventional building.

Higher price per square meter.

Architecture Outstanding architectural

design can be achieved at low

cost using standard

architectural details and

interfaces.

Special architectural design and

features must be developed for each

project which often requires research

and thus resulting in higher cost.

Sourcing And

Coordination

Building is supplied complete

with all accessories including

erection for a single one stop

source.

Many sources of supply are there so

it becomes difficult to co-ordinate

and handle the things.

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Cost of

Charge order

PEB manufactures usually

stock a large amount of that

can be flexibly used in many

types of PEB projects.

Substitution of hot rolled sections

infrequently rolled by mills is

expensive and time consuming.

Building

Accessories

Designed to fit the system

with standardized and inter

changeable parts. Including

pre designed flashing and

trims. Building accessories

are mass produced for

economy and are available

with the building.

Every project requires different and

special design accessories and special

sourcing for each item. Flashing and

trims must be uniquely designed and

fabricated.

Future

Expansion

Future expansion is very easy

and simple.

Future expansion is most tedious and

more costly.

Safety

Single source of

responsibility is there because

the entire job is being done by

one supplier.

Multiple responsibilities can result in

question of who is responsible when

the components do not fit in properly,

insufficient material is supplied or

parts fail to perform particularly at

the supplier/contractor interface.

All components have been

specified and designed

Components are custom designed for

a specific application on a specific

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Performance

specially to act together as a

system for maximum

efficiency, precise fir and

peak performance in the field.

job. Design and detailing errors are

possible when assembling the diverse

components into unique buildings.

2.3 PRE-ENGINEERED BUILDINGS or (PEB)

2.3.1. General

India being a developed country massive house building construction is taking place in

various parts of the country.[10] Since 30% of Indian population lives in towns and

cities; hence construction is more in the urban places. The requirement of housing is

tremendous but there will always be a shortage of house availability as the present

masonry construction technology cannot meet the rising demand every year. Hence

one has to think for alternative construction system for steel or timber buildings, but

timber is anyway not suitable to tropical countries like India.

In structural engineering, a pre-engineered building (PEB ) is designed by a

manufacturer to be fabricated using a pre-determined inventory of raw materials and

manufacturing methods that can efficiently satisfy a wide range of structural and

aesthetic design requirements. Within some geographic industry sectors these

buildings are also called Pre-Engineered Metal Buildings. Historically, the primary

framing structure of a pre-engineered building is an assembly of I shaped members,

often referred as I beam. In PEB, I section beams used are usually formed by welding

together steel plates to form of I section. I section beams are then field-assembled (e.g.

bolted connections) to form the entire frame of the pre-engineered building. Cold

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formed Z and C-shaped members may be used as secondary structural elements to

fasten and support the external cladding. Roll-formed profiled steel sheet, wood,

tensioned fabric, precast concrete, masonry block, glass curtain wall or other materials

may be used for the external cladding of the building.

In order to accurately design a pre-engineered building, engineers consider the clear

span between bearing points, bay spacing, roof slope, live loads, dead loads, collateral

loads, wind uplift, deflection criteria, internal crane system and maximum practical

size and weight of fabricated members. Historically, pre-engineered building

manufacturers have developed pre-calculated tables for different structural elements in

order to allow designers to select the most efficient I beams size for their projects.

In pre-engineered building concept the complete designing is done at the factory and

the building components are brought to the site in CKD (Completely knock down

condition). These components are then fixed / jointed at the site and raised with the

help of cranes. The pre-engineered building calls for very fast construction of buildings

and with good aesthetic looks and quality construction. Pre-engineered Buildings can

be used extensively for construction of industrial and residential buildings. The

buildings can be multi storied (4-6 floors). These buildings are suitable to various

environmental hazards. Pre-engineered buildings can be adapted to suit a wide variety

of structural applications; the greatest economy will be realized when utilizing standard

details. An efficiently designed pre-engineered building can be lighter than the

conventional steel buildings by up to 30%. Lighter weight equates to less steel and a

potential price savings in structural framework.

2.3.2 Features and Advantages

Features: Pre-engineered steel buildings use a combination of built-up sections, hot

rolled sections and cold formed elements which provide the basic steel frame work

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with a choice of single skin sheeting with added insulation or insulated sandwich panels

for roofing and wall cladding. The concept is designed to provide a complete building

envelope system which is air tight, energy efficient, optimum in weight and cost and,

above all, designed to fit user requirement like a well fitted glove. [6]

Pre-engineered steel buildings can be fitted with different structural accessories

including mezzanine floors, canopies, fascias, interior partitions etc. and the building

is made water proof by use of special mastic beads, filler strips and trims. This is very

versatile buildings systems and can be finished internally to serve any functions and

accessorized externally to achieve attractive and unique designing styles. It is very

advantageous over the conventional buildings and is really helpful in the low rise

building design.

Pre-engineered buildings are generally low rise buildings however the maximum eave

height can go up to 25 to 30 metres. Low rise buildings are ideal for offices, houses,

showrooms, shop fronts etc. The application of pre-engineered buildings concept to

low raise buildings is very economical and speedy. Buildings can be constructed in less

than half the normal time especially when complemented with the other engineered

sub systems.

The most common and economical type of low rise buildings is a building with ground

floor and two intermediate floor plus roof. The roof of low rise buildings may be flat

or sloped. Intermediate floors of low rise buildings are made of mezzanine systems.

Single storied houses for living take minimum time for construction and can be built

in any type of geographical location like extreme cold hilly areas, high rain prone areas,

plain land obviously and extreme hot climatic zones as well.

Advantages:

Reduction in Construction Time: Buildings are typically delivered in just a few weeks

after approval of drawings. Foundation and anchor bolts are cast parallel with finished,

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ready for the site bolting. In India the use of PEB will reduce total construction time of

the project by at least 50%. This also allows faster occupancy and earlier realization of

revenue.

Lower Cost: Due to the systems approach, there is a significant saving in design,

manufacturing and on site erection cost. The secondary members and cladding nest

together reducing transportation cost.

Flexibility of Expansion: Buildings can be easily expanded in length by adding

additional bays.

Also expansion in width and height is possible by pre designing for future expansion.

Larger Spans: Buildings can be supplied to around 80M clear spans.

Quality Control: As buildings are manufactured completely in the factory under

controlled conditions the quality is assured.

Low Maintenance: Buildings are supplied with high quality paint systems for

cladding and steel to suit ambient conditions at the site, which results in long durability

and low maintenance costs. Energy Efficient Roofing and Wall Systems: Buildings can

be supplied with polyurethane insulated panels or fiberglass blankets insulation to

achieve required U values [16]].

Architectural Versatility: Building can be supplied with various types of fascias,

canopies, and curved eaves and are designed to receive pre-cast concrete wall panels,

curtain walls, block walls and other wall systems.

Single Source Availability: As the complete building package is supplied by a single

vendor, compatibility of all the building components and accessories is assured. This

is one of the major benefits of the pre-engineered building systems.

2.3.3 Benefits of PEB:

Pre-engineered building systems provide real value to clients without sacrificing

durability, seismic and wind resistance, or aesthetic appearance. Cost savings begin

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right at the drawing preparation stage. Systems engineering and fabrication methods

help reduce interim financing costs through faster construction and minimized field

erection expense. An added benefit is earlier occupancy of the facility and a head start

on day-to-day operations by the client.

Apart from costs, there is an assurance of factory-built quality and uniformity in design

and fabrication. These systems are also energy efficient; incorporate watertight roofing

systems; enable easy disassembly or future expansion and have the lowest life cycle

maintenance costs.

Adding to these; there is no mess of sand and cement; power savings; walkable

ceilings; progressive and non-progressive panel systems for walls. A poor man can be

provided with a home created under strict quality control and having a longer life span,

with greater safety against natural disasters like earthquakes and cyclones.

Moreover, it is possible to create the building in required form and shape. And the

'system approach' renders a holistic way of thinking at one platform for consultants,

designers, architects, and builders. Thus it tends to achieve a perfect harmony among

various stringent specifications and aesthetic requirements in a most economical way.

In nutshell, the benefits may be summarized as under

• Easy future expansion/modification.

• Weather proof and fire hazards.

• Optimized design of steel reducing weight.

• International Quality Standards

• Seismic & Wind pressure resistant.

• Quality design, manufacturing and erection, saving around 30-40% of project

time

• Quick delivery and Quick turn-key construction.

• Pre-painted and has low maintenance requirement.

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• Erection of the building is fast.

• The building can be dismantled and relocated easily.

• Future extensions can be easily accommodated without much hassle.

• Increased Life cycle performance and cost competitiveness

• Environment friendly structures

• Better rainwater harvesting through gutters and down-take arrangements

• Lighter weight; savings in foundation cost of 10-20 percent

• The building can be dismantled and relocated easily

• Easy integration of all construction materials

• Energy efficient roof and wall system using insulations.

• Suitability for Hilly regions and other geographically difficult areas

• Unlimited architectural possibilities

2.3.4 Applications of PEB

Almost every conceivable building use has been achieved with PEB the most common

applications are industrial, institutional and commercial.

In India, Pre-engineered building systems find application primarily in the construction

of Warehouses, & Industrial sheds & Buildings. The recent focus has also shifted to

cover rural as well as urban, individual and mass housing projects, farmhouses, slum

re-organization projects and rehabilitation projects, amenity structures like health

centre, kiosks, primary schools, panchayats etc. The pharmaceutical industries and

exhibition centre, and functional requirements like offices, seminar halls, call centre,

supermarkets, showrooms etc. [6] have also attracted PEB. Earthquake-resistant

buildings are the recent applications of PEB with wide and immediate acceptance.

PEB concept has acted as a catalyst in the infrastructure development of the country.

Single storied houses for living take minimum time for construction and can be built

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in any type of geographic location like extreme cold hilly areas, high rain prone areas,

plain land, extreme hot climatic zones etc.

Applications of Pre-engineered steel buildings include

• Houses & Living Shelters

• Factories

• Warehouses

• Sport Halls ( Indoor and Outdoor)

• Aircraft Hangers

• Supermarkets

• Workshops

• Office Buildings

• Labour Camps

• Petrol Pumps/Service Buildings

• Schools

• Community centres

• Railway Stations

• Equipment housing/shelters.

There is a great possibility of improving the aesthetic quality with a choice of roofing

elements, exterior finishes, weather-sheds, colour system and variations in planning as

well as massing.

2.4 PROFILE OF PEB

All over the world, pre-engineered building system or PEB system is becoming an

eminent segment in pre-engineered construction industry. It has become possible

because pre-engineered building system encompasses all the characteristics that are

23

compatible to modern demands viz. speed, quality and value for money. Pre-

engineered buildings find many pre-engineered construction applications, which could

be intrinsic and high-end.

PEB prospect in the world:

Technological improvement over the year has contributed immensely to the

enhancement of quality of life through various new products and services. One such

revolution was the pre-engineered buildings. Through its origin can be traced back to

1960 s its potential has been felt only during the recent years. This was mainly due to

the development in technology, which helped in computerizing the design.

PEB concept has been very successful and well established in North America, Australia

and is presently expanding in U.K and European countries. PEB construction is 30 to

40% faster than masonry construction. PEB buildings provide good insulation effect

and would be highly suitable for a tropical country like India. PEB is ideal for

construction in remote & hilly areas. [16]. A recent survey by the Metal Building

Associations (MBMA) shows that about 60% of the non- residential low rises building

in USA are pre-engineered buildings.

MARKET POTENTIAL

PEB systems are extensively used in industrial and many other non- residential

constructions worldwide, it is relatively a new concept in India. These concepts were

introduced to the Indian markets lately in the late 1990 s with the opening up of the

economy and a number of multi nationals setting up their projects. The market potential

of PEB is 12 lakh Metric tonnes per annum. The current pre-engineered steel building

manufacturing capacity is 0.35 million tonnes per annum. The industry is growing at

the compound rate of 25 to 30 %. [16]

24

FUTURE OF PEB

The steel structures (SS) market in India is in excess of 4.5 Mn.MT, growing at a rapid

pace of more than 10% p.a. over the past few years. This market has experienced a

higher growth compared to both Indian steel industry as well as Indian construction

GDP. Overall construction sector accounts for majority (greater than 80%) of the steel

structures market (volume terms) in India.

The current pre-engineered steel building manufacturing capacity is 0.35

million tonnes per annum. The industry is growing at the compound rate of 25 to 30%.

2.4.1 PRODUCTION

Pre-engineered Steel Buildings are tailor made buildings which are those fully

manufactured in the factory after designing. This fabrication is done in a controlled

environment with latest technology. The production is done under standard conditions.

The Raw material required is imported from major companies like Tata BlueScope to

all the companies in India.

Historically, the primary framing structure of a pre-engineered building is an

assembly of I shaped members, often referred as I beam. In pre-engineered buildings,

I beams used are usually formed by welding web and flange plates together to form I

section. I beams are then field assembled (e.g. bolted connections) to form the entire

frame of the pre-engineered building. Some manufacturers taper the framing members

(varying in web depth) according to the local loading effects. Larger plate dimensions

are used in areas of higher load effects.

Cold formed Z and C-shaped members may be used as secondary structural

elements to fasten and support the external cladding. Roll-formed profiled steel sheet,

wood, tensioned fabric, precast concrete, masonry block, glass curtain wall or other

materials may be used for the external cladding of the building.

25

2.4.2 MANUFACTURING OR PROCESSING

Manufacturing is done through the raw material which is imported from steel

production companies. The imported steel is in the form of rolled sheets. For the hot

rolled and cold formed sheets cutting is done to desired dimensions and welded with

submerged arc welding.

The PEB production process primarily consists of FOUR major parallel processing

lines, as under:

1. Built-up members for Primary frame

2. Cold forming for Secondary framing

3. Profiling for Roof and Wall

sheeting

4. Accessories & Bracings like

Gutters, down take pipes, ridge

Vents, Skylights, clips etc.

The design and final processing inspection is done for production, ready for shipment

in completely knocked Down Condition (CKD) conditions.

1. Plate cutting using Shear/Plasma/Multi-torch through nesting software for

optimized use of plate area.

2. H-beam welding on automatic welding machines using SAW or MIG welding

process

3. Fabrication for fitments like end plates, stiffeners and connections cleats.

4. Cleaning the surface for painting

5. Slitting HR coils for cold forming operations to make Z and C sections with

punching

26

6. Cutting and threading sag rods and bracing rods

7. Fabrication of Diagonal bracing angles or pipes

8. Profiling the Galvalume / Zincvalume sheets for roofing and wall cladding

9. Manufacturing Gutters, down take pipes in press bend

10. Procuring and assigning required matching fasteners for connections

11. Organizing some bought out accessories

12. Quality control tests & inspection; and matching with project wise Bill of

Quantities as given by the engineering department.

13. Dispatching to project sites as per sequence of erection

2.4.3 STRUCTURAL FRAMING

All framing members shall be shop fabricated for field bolted assembly. The surfaces

of the Bolted connections shall be smooth and free from burrs or distortions. All shop

connections shall be in accordance with the manufacturer's standard design practices.

Primary framing

All rigid frames shall be welded built-up "I" sections or hot-rolled sections. The

columns and the rafters may be either uniform depth or tapered. Flanges shall be

connected to webs by means of a continuous fillet weld on one side. All end wall roof

beams and end wall columns are in cold formed "C" sections, mill-rolled sections, or

built-up "I" sections depending on design requirements. All base plates, splice and

flanges shall be shop fabricated to include bolt connection holes. Webs are shop

fabricated to include bracing holes. [16]

Secondary Framing

Purlins and girts shall be cold-formed "Z" sections with stiffened flanges. Flange

stiffeners shall be sized to comply with the requirements of the latest edition of AISI.

Purlin and girt flanges shall be unequal in width to allow for easier nesting during

27

erection. They shall be pre punched at the factory to provide for field bolting to the

rigid frames. They shall be simple or continuous span as required by design.

Connection bolts will install through the webs, not flanges. [16]

Bracing

Diagonal bracing in the roof and sidewalls shall be used to remove longitudinal loads

(wind, crane, etc.) from the structure. This bracing will be furnished to length and

equipped with bevel washers and nuts at each end. It may consist of rods threaded each

end or galvanized cable with suitable threaded end anchors. If load requirements so

dictate, bracing may be of structural angle and/or pipe, bolted in place. [16]

Welding

Welding is a fabrication or sculptural process that joins materials, usually metals. In

Pre-engineered Steel Buildings the hot rolled steel sections are subjected to submerged

arc welding. Shielding gas is used in order to protect the welding region. Welding is

Done by passing the Steel plates into the welding machine, which welds along the

joints. In PEB the Tapered sections are welded, but at some locations manual welding

is done. Double side welding is preferred according to Indian Code but Single side

Welding is much beneficent because it increases the Quality of steel sections. Single

side welding is more economical, all manufactures follow the American code which

states Single side welding.

Base plates are welded to base of columns for the structural strength. These base plates

are provided with bolt holes. Anchor bolt dimensions are taken into account for Base

plate preparation. [16]

Anchor Bolts:

Anchor bolts are manufactured with circular steel rods having threading portion at the

top for bolting and bent up at the bottom for Foundation. These are bent at 90 degrees

28

for embedding into the soil. The dimensions for Anchor bolts are taken from support

reactions of the columns.

Surface Preparation:

The surface of columns and rafters are prepared in order to protect it from rusting.

Abrasive paper is used to scrub the top layers of columns and rafters in order to remove

accumulated rust on the top of the sections. This is old method, it is done manually.

Advancement technologies avoided manual procedure and brought Sand blasting and

short blasting into existence.

Sand blasting: Sand Blasting is a method in which sand is blown with high velocities

to the members. This is blown with sand particularly with 2 to 4 mm thick sand and

surface is cleared.

Short Blasting: Short blasting is a latest process in which members are sent into the

machine and hit with iron balls of 3mm thick under a huge velocity. Periodical removal

of rust is done in case of short blasting. Short blasting is observed as more efficient

surface cleaning process

Varnishing or Painting: Normally the primary and secondary steel are coated with

one coat (35 microns) of red oxide paint without any special treatment to steel.

However, if some special paint has to be applied to steel in order to give better anti-

corrosion properties etc. then the steel members have to be shot-blasted and then coated

with the special paints.

2.4.5 ERECTION

Steel construction is considered as a process that involves many related activities. Pre-

engineered buildings (PEB) steel parts are required to be installed in a specific order

due to structural safety requirements and to the logical sequence of erection. However,

29

shipping, transportation, unloading and on-site storage does not take into account the

erection order of the assembly. As a result, considerable time is consumed locating,

sorting, and identifying steel Components.

Integrating promising information technologies such as radio frequency identification

(RFID), mobile computing devices and wireless technology can be useful in improving

the effectiveness and convenience of information flow in construction projects. Pre-

engineered buildings require repetitive operations and assembly of many structural

elements.

Pre-engineered buildings (PEB) steel parts are required to be installed in a specific order

due to structural safety requirements and to the logical sequence of erection.

Erection Drawings:

Erection drawings provide the field erection crew (raising gang) with the roadmap of

how to erect (put together) the steel assemblies after they are delivered to the field.

Essentially, they are a set of instructions on how to put the puzzle pieces together.

Every assembly shipped to the field is given a shipping piece number to identify it.

This number is noted on the drawing and is also stenciled onto the actual assembly of

steel. Erection drawings illustrate how the connections will be fabricated in the field.

2.4.6 CONSTRUCTION OVERVIEW:

Before the PEB Components arrives, the site and foundation should be prepared. This

includes levelling the terrain and constructing the foundation.

A. Remove trees, debris, and other items from the building

location.

B. Smooth and level the ground where the foundation is to be

made.

30

C. Construct the foundation using the materials recommended as per design parameters.

Transiting on all corners the foundation locations are determined and trenches are made

for foundation. In foundation trenches the Anchor bolts are set along with the concrete.

Anchor Bolt Setting:

It is extremely important that anchor bolts be placed accurately in accordance with the

anchor bolt setting plan. All anchor bolts should be held in place with a template or

similar means, so that they will remain plumb and in the correct location during placing

of the concrete. Check the concrete forms and anchor bolt locations prior to the pouring

of the concrete. A final check should be made after the completion of the concrete work

and prior to the steel erection. This will allow any necessary corrections to be made

before the costly erection labor and equipment arrives.

Unloading and Preparing Parts assembly:

The vehicle transporting your building parts must gain access to the building site from

the adjacent highway or road. Such access should be studied and prepared in advance

of arrival. When the truck arrives with the building, unload the truck promptly, stack

the steel parts evenly on blocks and protect them from the weather. Unloading and

placing the steel parts of the building in the most convenient places for assembly will

make the process easier and faster.

Blocking under the columns and rafters protects the splice plates and the slab from

damage during the unloading process. Extra care should always be exercised in the

unloading operation to prevent injuries from handling the steel and to prevent damage

to materials.

If water is allowed to remain for extended periods in bundles of primed parts such as

girts, purlins, etc., the pigment will fade and the paint will gradually soften reducing

its bond to the steel. Therefore, upon receipt of a job, all bundles of primed parts should

be stored at an angle to allow any trapped water to drain away and permit air circulation

31

for drying. Puddles of water should not be allowed to collect and remain on columns

or rafters for the same reason.

Location of Building Parts:

All the parts are placed around the foundation so that they will be in the most

convenient locations for installation. Bolts and nuts are placed where they will be

accessible to the parts. Purlins and girts, depending on the number of bundles, are

usually stored near the sidewalls clear of other packages or parts. Sheet packages are

usually located along one or both sidewalls off the ground and sloping to one end to

encourage drainage in case of rain. Accessories are usually unloaded on a corner of the

slab or off the slab near one end of the building to keep them as much out of the way

as possible from the active area during steel erection.

2.4.7 COMPONENTS ERECTION

The major components comprise of rigid frame, columns and rafter, eave struts, purlins,

girts, flange braces, end-wall columns and bracing systems which may be cables, rods

angles or portals. All materials for the first bay erection are prepared. The rafter sections

required are identified by part number, and then assembled as near as possible to their

lifting positions. Then the first four columns are erected at the braced bay, meanwhile

the part number, Orientation and position over anchor bolts were verified. Next step is

to position the crane for lifting the assembled rafter sections.

Raising Rigid Frames:

The intermediate or interior frames nearest the bearing end wall are usually erected

first. This bay usually contains the diagonal bracing. The proper completion and

plumbing of this first bay is extremely important to the successful completion of the

building. Although several methods are used to erect rigid frames, it has been found

32

most satisfactory to erect the columns first, tie them together with the girt and tighten

the anchor bolts. On small spans and short eave heights, columns can often be set in

place by hand without the use of hoisting equipment. Temporary bracing should always

be installed as soon as sections are lifted in place.

Completing and Plumbing the First Bay:

After the first intermediate or interior frames have been set, all purlins, girts, and eave

struts be installed in the braced bay and the entire bay plumbed, aligned and braced

before proceeding further. If the building is designed without cable bracing, the erector

is responsible for providing temporary erection bracing. When this bay is properly and

accurately plumbed and braced, the remaining members, to a large degree, will

automatically plumb and align when installed.

After the columns have been erected, the ground-assembled rafter is hoisted into place

and connected to the columns. The size of the rafter that can be safely handled depends

on the equipment available and the experience of the erection foreman. Generally as

many connections as possible are made on the ground.

The flange brace should be bolted to the rafter prior to raising in order to save time. The

hoisting equipment should never be released from the rafter until the frame is adequately

braced, so it cannot buckle or tip in the longitudinal direction of the building. The same

general procedures of erection apply to either clear span or multiple span frames.

Two words of caution concerning the erection of rigid frames are in order. The first is

that rigid frames, especially free ends or cantilevered sections should never be left for

the day in an unsupported, unbraced condition. Such practice has resulted in the total

loss of considerable amounts of erected steel because of wind. The second word of

caution pertains to the additional care required in the erection of multiple span frames

compared to clear span frames. Frames with interior columns, because of closer

supports, have much lighter sections. They are much more apt to buckle during erection

than clear span frames, and consequently require greater care in rigging and handling.

33

Erecting column Beam end walls:

Column and beam end walls of 50 feet or less in span may be raised into position and

set on the anchor bolts as a unit. All rafters, column, girts (except outside end wall girts

which connect to the sidewall girts), door headers, door jambs, clips, diagonal brace

rods, etc. should be assembled on the ground with the bolts left finger tight. A spreader

bar should be used to raise the end wall frame. Because of the flexibility of the column

and beam frames, care must be taken in locating the points of attachment of the cables,

and in raising the frame, to avoid bending about the minor axis.

For spans of 60 feet and greater, the columns are usually erected first and then capped

with the end wall rafter. Girts, headers, jambs and diagonal brace rods are then added

between the end columns. During this erection process, the frame must be properly

braced or guyed before the lifting lines are disengaged. Final bolt tightening should be

done once the frame is plumb and square.

Erecting the remaining frames:

The remaining frames are erected in like manner, initially with only a few purlins being

installed in each bay, as shown below, working from one end of the building to the

other. To lend overall rigidity to the structure, install flange braces to the purlins at

specified locations. All purlin, girt and eave strut connection bolts are left loose so that

the entire skeleton framework can be plumbed without undue difficulty. The remaining

purlins can be positioned on the rafter in each bay to facilitate the completion of the

roof framing.

Installation of Bracing:

Diagonal bracing in metal buildings is critical. They provide support for wind loads or

other longitudinal loads, such as those created by an overhead crane in the completed

structure. Many times additional temporary bracing is needed to stabilize the structure

during erection. On some smaller buildings, diagonal bracing is not needed for the

building design, so the erector must furnish any erection bracing needed.

34

Assemble the next brace cable the same way and connect to the next column to form

an X with the other cable. To square the building, measure the length of the diagonal

cables and tighten or loosen the turnbuckle/eye-bolt until the cable lengths are the

same. Brace each sidewall frame the same way so that you have an x-brace on each

side. Tighten the column anchor nuts after insuring that the building is square.

The diagonal bracing is cable. It should always be installed as shown on the erection

drawing and should be tensioned so that the building will not sway or rock when the

wind blows. Care should be taken, however, not to over tighten and bend the structural

members. The workman should watch the structural members carefully as he tightens

the bracing. Occasionally the bracing in the wall of a building cannot be installed in

the specified bay because of doors or other complications. Usually these can be moved

to other bays without affecting the structural integrity of the building.

Bolting Procedure in steel structures:

This procedure applies to the permanent fixing of steel structures including the erection

of steel. Construction drawings shall indicate the grade and diameter of all bolts, nuts

and washers required for the construction. Drawings shall indicate whether a Friction-

Type or Bearing Type connection is required. The nominal size of the bolt holes (other

than holes in a base plate) shall be 2mm larger than the nominal bolt diameter for a bolt

not greater than 24mm in diameter and not more than 3mm larger for bolts of diameter

more than 24 mm.

Alignment and assembly

The parts to be joined shall line up in such a way that a drift of equal diameter to the

bolt can pass through the bolt holes. Drifting to align the bolt holes shall be done is

such a 3 way as not to bend or damage the parts nor enlarge the holes. Packing shall be

provided as required to ensure parts have full contact over the mating surfaces. Prior

to inserting the bolts the nut should be run up the threads to ensure there are no thread

defects that would impede the tightening process.

35

Bolts shall be inserted through the holes after alignment from such a direction that the

nut has easiest access for tightening.

Bolt Tightening (Snug Tightening)

Bolt Tightening is required for all Bearing-Type Connections and as a pre-requisite to

Friction Type connections. The sequence of tightening the bolts shall proceed from the

stiffest part of the connection towards the free edges. High strength bolts that are to be

tensioned may be tightened during erection to facilitate assembly but they shall not be

finally tensioned until all bolts have been snug tightened in the correct sequence. Bolt

tightening is also known as snug-tightening. Bolt or snug tightening is achieved either

by subjecting the nut to a few impacts of an impact wrench after standard effort

tightening with a spanner or by the full effort of a person using a standard spanner. The

sequence of tightening is to firstly tighten all nuts with a standard effort and then to

snug tighten using a full effort or an impact wrench.

Wall Insulation

Fiberglass blanket insulation is the most common type used, and these instructions

pertain to this type only. One side of the blanket insulation should have a vapour barrier

that must face the inside of the building regardless of whether the insulation is for

heating or cooling.

Cut the insulation to length allowing an additional 6 or more to facilitate handling. The

wall panel can be used as a guide. The first run of wall insulation should be installed

so that its forward edge is just ahead of the leading edge of the wall panel. This keeps

the forward edge of the insulation ahead of the wall panel for joining the next blanket.

Roof Insulation:

Pre-cut roof insulation to reach from eave to eave allowing approximately 2 feet of

additional length to facilitate handling. Hold insulation at one sidewall and roll out

insulation across the purlins, vapour barrier to the inside of the building. Stretch the

36

insulation to provide a tight and smooth inside surface. Double sided tape or contact

adhesives can be used to hold insulation in place while the roof sheets are being

installed. Trim excess insulation to the edge of the eave trim and cut fiberglass

approximately 4 inches from end leaving only facing. Fold facing over end of blanket

insulation to seal the end.

Aligning the Girts:

Installation of the building walls is generally done before the roof. Before starting the

wall installation, check to be sure that the eave strut and girts are straight and plumb.

One method of aligning the Girts is to cut temporary wood blocking to the proper length

and install between the lines of girts. This blocking can be moved from bay to bay,

which will reduce the number of pieces required. Normally, one line of blocking per

bay will be sufficient. Banding can also be used to hold the girt straight and plumb.

Screw alignment:

Good alignment of the screws, especially on the wall panels, will give a professional

appearance to the wall panel installation. One way this can be accomplished is by pre-

drilling holes in the panels at identical locations. Up to 15 panels can be stacked

together and drilled using a template panel. 1/8 or 5/32 diameter drill bit is used for

panel to structural fasteners and a 1/4 diameter bit for the side lap clearance holes.

Installation of wall Panels:

Adjoining panels are installed with the overlapping rib toward the last erected panel.

Position panel to structural making sure that it is kept plumb and install fasteners at

lapped rib. Check for proper coverage and correct as necessary. Install remaining

fasteners.

37

Fastener Installation:

Correct fastener installation is one of the most critical steps when installing roof panels.

Drive the fastener in until it is tight and the washer is firmly seated. Do not overdrive

fasteners: A slight extrusion of neoprene around the washer is a good visual tightness

check.

Always use the proper tool to install fasteners. A fastener driver (screw gun) with and

rpm of 1700-2500 is used for self-drilling screws.

Preparing the Eave:

After installing the first run of insulation, prepare the eave for the first roof panel by

applying tape sealant along the eave outside of the insulation and leaving release paper

in place. Sealant must be applied in a straight line and without voids. Splice a full

closure to the starting closure and apply along the top of the eave sealant. If roof is

subject to ice and snow build-up, the splice in the closure strip must be caulked to

insure weather tightness.

Installation of the first roof panel:

Once the eave is prepared, the first roof panel may be installed. The roof panel is set in

place over the inside closure (after removing the paper from the mastic) ensuring the

major ribs of the panel nest properly with the inside closure.

Align the centre of the major rib of the panel edge with the edge of the end wall

roofline. With the panel properly placed, secure the panel to the structure with

appropriate fasteners.

38

Roof Sheeting Sequence:

It is recommended that both sides of the ridge of a building be sheeted simultaneously.

This will keep the insulation covered for the maximum amount of time and the panel

ribs can be kept in proper alignment for the ridge panel.

Final Installation:

While back lapping the last roof panel (to match panel coverage with the building

length) is routinely done, this installation method can compromise the integrity of the

roof by trapping moisture between the panels. This moisture could, in time, create an

environment conducive to rust and metal failure. Manufacturer recommends field

cutting the final panel lengthwise to create the desired panel width necessary to finish

off the building. The cut edge of the panel should always be installed on the outside

edge, not the lap edge. The narrow panel should be handled with care, and foot traffic

avoided until the final panel is completely installed.

Skylight Installation:

Skylight panels are installed using the same procedures as a steel panel. Care should

be taken when installing fasteners in the skylights to avoid cracking the material. Install

roof panels, leaving the light-transmitting panel run open, except for lower light

transmitting panel run panel. Install tape sealer to panel side laps and across panel

width as normal. Lay light transmitting panel in place overlapping lower metal panel

[6]. Apply double run of tape sealer across light transmitting panel width at lower and

middle purlins.

39

2.5 SCOPE FOR FUTURE STUDY

2.5.1. TRACKING GROWTH OF PEB

Emerging from their hiding places in concrete columns pre-engineered steel structures

(PEB s) are innovative solutions for construction projects across several sectors now

as discovers.

As Infrastructure construction across the country is combining speed, economy,

safety, strength and aesthetics at awe inspiring levels, steel structures, until now a

primary foundation element, have risen as complete solutions in construction projects

for various structural requirements. India is growing fast as an economy for pre-

engineered buildings (PEB s) as it is witnessing a boom in the infrastructure sector.

Structural steel buildings or PEB s are addressing parameters including finishes,

environment control and life cycle with a panache derived from product innovation

and technology advancement.

Emerging as a strong alternative to conventional concrete construction methods, PEB

in India is validated by the 33% market share of PEB s in the construction industry.

While this figure is lower than some European countries, it marks India's growing

global market share at 9.5 percent -- a step ahead of China's 8.5 percent. "The market

demand is pegged at 425,000 TPA with a 15% growth per annum,"(Kirby). "Current

market size is around Rs.3.500 Crores and it is expected to grow at 10% to 15% per

year,"

Strength Building:

With the country's five year plan catering for infrastructure addition in the form of

airports, metros and bridges sector differentiation is expected to separate industrial

buildings and building systems. These include Design & Engineering, Manufacture

and Construction & Erection. This pattern of restructuring indicates an industry that

40

sees PEB s coming into its own with experiencing exponential growth with

diversification into various sectors and segments.

Add to that the reduced time to completion with the benefit of quality, and there is recipe

for success.

"PEB is getting its due credit as a favourable alternative construction methodology in

India today. More sectors are realizing the benefits of metal over brick and mortar.

The scope of metal/steel buildings is very vast for the Indian market. PEB proves to

be relevant and beneficial to several construction verticals including warehousing,

infrastructure, oil & gas refineries as well as group housing,"(Kirby). "The advantages

of having a steel structure or building over traditional concrete are far too many.

Primarily, speed and quality of construction are the top two benefits. Steel buildings

are fire, quake and cyclone resistant hence from a safety and longevity perspective,

these buildings are timeless".

2.5.2 SCOPE FOR FUTURE STUDY

Multi Storey Buildings:

PEB has boon to Multi storey Buildings in India. Decking sheets with concrete over

can be used as roofing and raised to any extent above 40 meters. These have a tracking

rate of 80% in western countries.

Fibre Glass Wool Insulation for PEB:

A critical and necessary ingredient in the PEB System is thermal and acoustic

insulation. This is necessary to minimize heat gain (or energy loss, for an air

conditioned building) as well as to provide acoustic insulation from heavy rain and

other outside noises. In a typical PEB structure, the roof accounts for approx. 40 to

50% of total heat gain, while walls account for approx. 15 to 20% of heat gain. [6]

41

Almost 100% of PEB s world-wide are insulated for the following reasons.

• Minimize heat gain

• Maximize thermal comfort

• Minimize energy loss, cooling load and operating cost for air conditioned

buildings

• Provide acoustic insulation

• Prevent unwanted moisture condensation

Cellular Columns or Rafters:

Cellular beams can achieve the same strength as solid I beams of the same depth with

significantly less steel use resulting in Lighter weight. These beams offer designers a

number of opportunities for sizes and sections including varying the depth of the beam

and creating tapered sections.

Standard Seam Roofina:

Standard Seam roofina which is particularly used for sheeting. Sheets are not punched

and rolled to one above the other in order to protect leakage of water during rains.

42

CHAPTER 3

METHODOLOGY

3.1 GENERAL:

Pre-engineered Buildings are custom designed to meet client s requirements. PEB are

defined for definite measurements. The produced members fit to the designed

dimensions. Measurements are taken accurately for the requirements. The basic

parameters that can define a PEB are as follows.

3.1.2 WIDTH OR SPAN OF BUILDING:

The centre to centre length from one end wall column to the other end wall column of

a frame is considered breadth or span of the building. The width between two columns

can be measured as span. The span length for different buildings varies. The design is

done on span length given by customer. [16] The basic span length starts from 10 to

150 meters or above with intermediate columns. Aircraft hangars, manufacturing

industries, Stadiums possess major span width. No modifications or extending span be

done.

3.1.3 LENGTH OF BUILDING:

The length of PEB is the total length extending from one front end to the rear end of the

building. The length of PEB can be extendable in future.

3.1.4 BUILDING HEIGHT:

Building height is the eave height which usually is the distance from the bottom of the

main frame column base plate to the top outer point of the eave strut. When columns

are recessed or elevated from finished floor, eave height is the distance from finished

floor level to top of eave strut.

43

3.1.5 ROOF SLOPE:

This is the angle of the roof with respect to the horizontal. The most common roof

slopes are 1/10 and 1/20 for tropical countries like India. The roof slope in snow fall

locations can go up to 1/30 to 1/60. Any practical roof slope is possible as per customer

s requirement.

3.1.6 DESIGN LOADS:

Unless otherwise specified per-engineered buildings are designed for the following

minimum loads. The designed loads play a crucial role in case of PEB. The failure of

the structures occurs if not properly designed for loads.

The determination of the loads acting on a structure is a complex problem. The nature

of the loads varies essentially with the architectural design, the materials, and the

location of the structure. Loading conditions on the same structure may change from

time to time, or may change rapidly with time.

Loads are usually classified into two broad groups as dead loads and live loads. Dead

loads (DL) are essentially constant during the life of the structure and normally consist

of the weight of the structural elements. On the other hand, live loads (LL) usually vary

greatly. The weight of occupants, snow and vehicles, and the forces induced by wind

or earthquakes are examples of live loads. The magnitudes of these loads are not known

with great accuracy and the design values must depend on the intended use of the

structure. [6]

Dead Load:

The structure first of all carries the dead load, which includes its own weight, the weight

of any permanent non-structural partitions, built-in cupboards, floor surfacing

materials and other finishes. It can be worked out precisely from the known weights of

the materials and the dimensions on the working drawings.

44

Live Load:

All the movable objects in a building such as people, desks, cupboards and filing

cabinets produce an imposed load on the structure. This loading may come and go with

the result that its intensity will vary considerably. At one moment a room may be

empty, yet at another packed with people. Imagine the `extra' live load at a lively party.

Wind loads:

Wind has become a very important load in recent years due to the extensive use of

lighter materials and more efficient building techniques. A building built with heavy

masonry, timber tiled roof may not be affected by the wind load, but on the other hand

the structural design of a modern light gauge steel framed building is dominated by the

wind load, which will affect its strength, stability and serviceability. The wind acts both

on the main structure and on the individual cladding units. The structure has to be

braced to resist the horizontal load and anchored to the ground to prevent the whole

building from being blown away, if the dead weight of the building is not sufficient to

hold it down. The cladding has to be securely fixed to prevent the wind from ripping it

away from the structure.

Roof load:

Live loads produced by maintenance activities, rain, erection activities, and other

movable or moving loads by not including wind, snow, seismic, crane, or dead loads.

Roof snow load:

Gravity load induced by the forces of wind blowing from any horizontal direction.

Collateral loads:

The weight of any non-moving equipment or material such ceilings, electrical or

mechanical equipment, sprinkler system, or plumbing.

Auxiliary loads:

45

Dynamic loads induced by cranes, conveyers, or other material handling systems.

Seismic loads:

Horizontal loads acting in any direction structural systems due to action of an

earthquake.

Floor Live loads:

Loads induced on a floor system by occupants of a building and their furniture,

equipment, etc.

3.1.7 BAY SPACING:

The distance between the two adjacent frames of a building is called as a Bay spacing.

The spacing between two frames is a bay. End Bay length is the distance from outside

of the outer flange of end wall columns of centre line of the first interior frame columns.

Interior bay length is the distance between the centre lines of two adjacent interior main

frames Columns. The most economical bay spacing is 7.5m to 8.0m. However bay

length up to 10m is possible.

3.1.8 TYPES OF FRAME:

A frame is a combination of Columns and inclined beams (rafters). There are

various type of frames. [6]

Clear Span (CS):

The span length between two columns without any obstruction. It has split Beams with

ridge line at the peak or centre of the building. The maximum practical width or span

is up to 90 meters, but it can also be extended up to 150 meters in case of Aircraft

Hangars. Arched Clear Span: The column is an RF column while the Rafter is curved.

It has no ridge line and peak. The curved roof rafter is used in for aesthetic look. The

maximum practical is up to 90 meters, but can be extended to 120 meters.

46

Multi Span (MS):

The Multi spans (MS) are those which have more than 1 span. The intermediate column

is used for the clear span in which width of each span is called width module.

Arched Multi Span (AMS):

Arched multi span has RF column and a curved Rafter with one intermediate column.

It has width module for the entire span.

Multi Span (MS):

The Multi Span (MS) has more than one intermediate span. It has three width modules

with one ridge line.

Single Slope:

It has two columns with different heights having Roof sloping on both the columns.

Multi Gable:

Multi gable has two or more spans where no intermediate columns are used. The

columns are added to the extended width and columns are not placed at the ridge lines.

Roof Systems:

It has straight columns with Roof having supports are not by TPCA.

Lean To:

Lean to slopes is used extremely for an extending to a building on either side with short

span. The rafters rest on column designed for lean to on one side and rests on the main

column of the building.

Canopy:

Canopies are used in case of open ends where there is an easy access. There are columns

in straight path having roof extended to a large length.

47

3.1.9 SUBSYSTEMS

Major companies use standard components and designs to manufacture a wide range

of structural subsystems according to customers' requirements. These structural

subsystems fulfil the requirements of two type’s viz. Aesthetic and Functional. They

produce a large number of structural subsystems according to exact specifications as

the strength of the pre-engineered building system depends largely on various

incorporated structural subsystems. Subsystems are available for following structures

End wall Roof Extension: End wall roof extensions consist of end wall panel, Roof

panel, Gable trim, soffit panel, and end wall rafter. The end wall is extended to an

extent under end wall panel support.

Sidewall Roof Extension: The sidewall roof extension has the same assembly but the

soffit panels are above the Roof Extension Rafter.

Centre Curved Fascia: The centre curved fascia consist Backup panel, soffit panel. It

is an assembly of Cap flashing, Fascia panel with valley gutter or eave gutter on the

rafter with rigid frame support.

Bottom Curved Fascia: The entire assembly of Centre curved fascia contains for the

Bottom curved Fascia a slight change in Connection of wall panel to Frame.

Top and Bottom Curved Fascia: In this the assembly is a combination of Top Curved

Fascia which has curvature at top and bottom curved Fascia having bottom Fascia. [6]

Roof Platform: The roof platform has Grating on above and roof panels on the sides.

3.2 COMPONENTS OF PEB

A typical assembly of a simple metal building system is shown below to illustrate

the Synergy between the various building components as described below and the

every component is discussed in detail as follows

48

The following are the several components of Pre - engineered building

1. Primary components

2. Secondary components

3. Sheeting (or) cladding

4. Accessories

Fig. 3.1. Schematic representation of a Pre- Engineered Building

49

3.2.1 PRIMARY COMPONENTS

Main framing:

Main framing basically includes the rigid steel frames of the building. The PEB rigid

frame comprises of tapered columns and tapered rafters (the fabricated tapered sections

are referred to as built-up members). The tapered sections are fabricated using the state

of art technology wherein the flanges are welded to the web. Splice plates are welded

to the ends of the tapered sections. The frame is erected by bolting the splice plates of

connecting sections together. All rigid frames shall be welded built – up "I" sections or

or hot-rolled sections. The columns and the rafters may be either uniform depth or

tapered. Flanges shall be connected to webs by means of a continuous fillet weld on

one side. All end wall roof beams and end wall columns shall be cold formed "C"

sections, mill-rolled sections, or built-up "I" sections depending on design

requirements. Plates, Stiffeners, etc. All base plates splice plates, cap plates, and

stiffeners shall be factory welded into place on the structural members. Built- up I

section to build primary structural framing members (Columns and Rafters)

Columns:

The main purpose of the columns is to transfer the vertical loads to the foundations.

However a part of the horizontal actions (wind action) is also transferred through the

columns.

Basically in pre-engineered buildings columns are made up of I sections which are

most economical than others. The width and breadth will go on increasing from bottom

to top of the column. I section consists of flanges and web which are made from plates

by welding.

50

Rafter:

A rafter is one of a series of sloped structural members (beams) that extend from the

ridge or hip to the wall-plate, down slope perimeter or eave, and that are designed to

support the roof deck and its associated loads.

Fig. 3.3 Schematic representation of a Rafter

Rafter

Fig. 3.2 Schematic representation of a Column

51

3.2.2 SECONDARY COMPONENTS

Purlins, Grits and Eave struts are secondary structural members used as support to

walls and roof panels. Purloins are used on the roof; Grits are used on the walls and

Eave struts are used at the intersection of the sidewall and the roof. They are supplied

with minimum yield strength of 34.5 KN/m. Secondary members act as struts that help

in resisting part of the longitudinal loads that are applied on the building such as wind

and earthquake loads and provide lateral bracing to the compression flanges of the main

frame members for increasing frame capacity. Purloins, Grits and Eave struts are

available in high grade steel conforming to ASTM 607 Grade 50 or equivalent,

available in 1.5 mm, 1.75 mm. 2.0 mm, 2.25 mm, 2.5 mm and 3.0 mm thickness. They

come with a pre-galvanized finish, or factory painted with a minimum of 35 microns

(DFT) of corrosion protection primer. Purlins and girts shall be cold formed "Z" section

With stiffened flanges. Flange stiffeners shall be sized to comply with the requirements

of the latest edition of AISI.

Purlins and Girts:

Purlins and girts shall be roll formed Z sections, 200 mm deep with 64 mm flanges

shall have a 16 mm stiffening lip formed at 45 to the flange. Purlins and girts shall be

cold-formed "Z" sections with stiffened flanges. Flange stiffeners shall be sized to

comply with the requirements of the latest edition of AISC .Purlin and girt flanges shall

be unequal in width to allow for easier nesting during erection. They shall be pre

punched at the factory to provide for field bolting to the rigid frames. [6] They shall be

simple or continuous span as required by design. Connection bolts will install through

the webs, not flanges

52

Fig. 3.4 Schematic representation of a Purlin

Eave Struts

Eave Struts shall be unequal flange cold-formed "C" sections. Eave struts are 200 mm

deep with a 104 mm wide top flange, a 118 mm wide bottom flange, both are formed

parallel to the roof slope. Each flange has a 24 mm stiffener lip.

Fig. 3.5 Schematic representation of a Eave Strut

53

Bracings:

The Cable bracing is a primary member that ensures the stability of the building against

forces in the longitudinal direction such as wind, cranes, and earthquakes.

Diagonal bracing in the roof and sidewalls shall be used to remove longitudinal loads

(wind, crane, etc.) from the structure. This bracing will be furnished to length and

equipped with bevel washers and nuts at each end. It may consist of rods threaded each

end or galvanized cable with suitable threaded end anchors [6]

3.2.3 SHEETING OR CLADDING:

The sheets used in the construction of pre- engineered buildings are composed of the

following:

Base metal of either Galvalume coated steel .Galvalume coating is 55% Aluminium

and about 45% Zinc by weight. An exterior surface coating on painted sheets of 25

microns of epoxy primer with a highly durable polyester finish.

An interior surface coating on painted sheets of 12 microns of epoxy primer and

modified polyester or foam. The sheeting material is cold-rolled steel, high tensile 550

MPA yield stress, with hot dip metallic coating of Galvalume sheet.

Fig. 3.6 Schematic representation of a GI Sheets

54

3.2.4 ACCESSORIES

Anchor bolts:

Bolts used to anchor the structural members to the concrete floor, foundation or other

support. This usually refers to the bolts at the bottom of all columns. Anchor bolts are

Anchor bolts are manufactured with circular steel rods having threading portion at the

top for bolting and bent up at the bottom for Foundation.

Fig. 3.7 Schematic representation of an Anchor Bolts

Turbo ventilators

A Turbo Ventilator is a free spinning roof ventilator that works on free wind energy.

When there is a difference in thermal or wind pressure between the inside and outside

of the building, the air is forced to move through the opening of the Turbo Ventilator

in order to maintain an equilibrium condition. The benefits of using turbo ventilators

Are that it improves air circulation and cuts off the suffocation. Eco friendly turbo

ventilator involves no operating cost, are free from maintenance and are has trouble

free operations.

55

Fig. 3.8 Schematic representation of an Air Vents

Sky lights (or) wall lights:

Sky lights may consists of poly carbonate sheets which is translucent sheet that allows

maximum light and minimum heat. High strength translucent panels are glass fiber

reinforced polyester, high strength and may be either and it provides with an estimated

light transmitting capacity of 60%. High strength translucent panels match standard

panel profiles, are 1/16 thick, weigh 8 ounces per square foot, and are white with a

granitized top surface.

Insulated translucent panels are available in type 1, "R" panel and standing seam profiles

only.

Damper, Standard size is 3000 mm long with a throat opening of 300 mm.

56

Fig. 3.9 Schematic representation of a Day Light Sheets

Louvers:

Standard Louvers shall have a 26 gauge galvanized steel frame, painted, with 26 gauge

blades. Heavy Duty Louver frames shall be 18 gauge galvanized steel frame, painted,

with 20 gauge blades They shall be equipped with adjustable or fixed blades as

specified. Nominal sizes shall be 2 -0" x 2 0" x 2'0", 3'-0" x 3'-0" 4'-0" x 3'-0", and 3'-

0" x 4'-0

Fig. 3.10. Schematic representation of a Louvers

57

Walking doors:

Walk doors are generally 915 mm or 1830 mm wide x 2134 mm high made of 20 gauge

electro galvanised steel with a core of polyurethane insulation. Door fixture is provided.

[6]

Aluminium windows:

Designed for installation with wall panel, double slide, self -flashing with pre-glazed

clear glass and removable half insect screen. Standard size is 1 m x 1 m. multiple

windows can be formed by joining the jamb fins together

Fasteners:

Standard fasteners shall be self -drilling screws with metal and neoprene washers. All

screws shall have hex heads and are zinc plated.

58

3.3 FLOWCHART OF METHODOLOGY CARRIED OUT

`

Assuming Dimensions, Structural Conditions

and Cross Sections

Structural Analysis

Selection Of cross Sections to satisfy Structural

requirements, performance

On Violating Initial

assumptions

On satisfying

Initial assumptions

Final design

Design of Column

Design of Rafter

Design of Purlin

Foundation

Design of Connection

59

CHAPTER 4

DESIGN OF PRE-ENGINEERED STEEL BUILDING

4.1 GENERAL

Pre-engineering of metal buildings can be optimized to meet specific design criteria.

Largely Indian and American practice of design is followed by most of the consultants

and PEB vendors in India these days. A brief of design codes used in each of these is

attached herewith:

The main framing of PEB systems is analysed by the stiffness matrix method. The

design is based on allowable stress design (ASD) as per the American institute of Steel

Construction specification or the IS 800. the design program provides an economic and

efficient design of the main frames and allows the user to utilize the program in

different modes to produce the frame design geometry and loading and the desired load

combinations as specified by the building code opted by the user. The program operates

through the maximum number of cycles specified to arrive at an acceptable design.

The program uses the stiffness matrix method to arrive at an acceptable design. The

program uses the stiffness matrix method to arrive at the solution of displacements and

forces. The strain energy method is adopted to calculate the fixed end moments,

stiffness and carry over factors. Numerical integration is used.

4.1.1 DESIGN CYCLE

The design cycle consists of the following steps:

1. Set up section sizes and brace locations based on the geometry and loading specified

for the frame design.

2. Calculate moment, shear, and axial force at each analysis point for each load

combination.

60

3. Compute allowable shear, allowable axial and allowable bending stress in

compression and tension at each analysis point.

4. Compute the corresponding stress ratios for shear, axial and bending based on the

actual and allowable stresses and calculate the combined stress ratios.

5. Design the optimum splice location and check to see whether the predicted sizes

confirm to manufacturing constraints.

6. Using the web optimization mode, arrive at the optimum web depths for the next cycle

and update the member data file.

7. At the end of all design cycles, an analysis is run to achieve flange brace optimization.

[16]

Frame Geometry:

The program has the capability to handle different types of frame geometry as follows

Frames of different types viz. rigid frames, frames with multiple internal columns,

single slope frames, lean to frames etc; Frames with varying spans, varying heights and

varying slopes etc. Frames with different types of supports viz. pinned supports, fixed

supports, sinking supports, supports with some degrees of freedom released.

Unsymmetrical frames with off centric, unequal modules, varying slopes etc. User

specified purlin and girt spacing and flange brace location.

Frame Loading:

Frame design can handle different types of loadings as described below:

All the building dead loads due to sheeting, purlins, etc. and the self- weight of the frame

and Imposed live load on the frame with tributary reductions as well.

Wind loads input such as basic wind speed or basic wind pressure that will be converted

to deign wind pressure as per the building code specified by the user and shall be

applied to the different members of the building according to the coefficients

mentioned in the codes prescribed by the user. The standard building codes like

61

MBMA, UBC, ANSI, IS: 875 parts 3 etc. are used for this purpose. Crane and non-

crane loading can be specified by the user and the program has the capability to handle

these special loads and combine them with the other loads as required.

Seismic loads corresponding to the different zone categories of various international

codes can also be defined and combined with other load cases as required. Temperature

loads can also be specified in the form of different differential temperature value on

centigrade and specifying the appropriate coefficient for the thermal expansion. Load

combinations with appropriate load factors can be specified by the user as desired.

4.2 Design of a warehouse

The majority of warehouse buildings are made out of steel for obvious reasons of high

strength/weight ratio. A study, on the Efficient Design of Large span

hangars/structures, is presented. A clear span of gable frame of 15 m is adopted and

the designs of Components are discussed below as follows

Structure with Span larger than 40 m can be regarded as long span structures and need

to be carefully designed keeping a balance of all the aspects like its weight, deflections

(sway) and foundation forces. There are many combinations of designing large spans,

like conventional truss & RCC column combination, truss & steel columns, Pre-

engineered building (PEB) etc.

These days with the concept of PEB, the major advantage we get is the use of high

strength steel plates (usually Fe 350), lighter but high strength cold form purlins, and

550 Map Galvalume profiled sheets. The use of PEB not only reduces the weight of

the structure because high tensile steel grades are used but also ensures quality control

of the structure. In the following study, we have designed a warehouse using this

modern concept of PEB. [16]

62

4.2.1 DESIGN PROCESS AND PRINCIPLES

Loads on Structure

The determination of the loads acting on a structure is a complex problem. The nature

of the loads varies essentially with the architectural design, the materials, and the

location of the structure. Loading conditions on the same structure may change from

time to time, or may change rapidly with time.

Dead load:

Dead loads shall cover unit weight/mass of materials, and parts or components in a

building that apply to the determination of the dead loads in the design of buildings

and shall be considered as per IS: 875 (Part 1) - 1987 according to the densities of the

possible components. This includes main frames, purlins, girt, cladding, bracing and

connections etc.

Live Load:

Imposed loads shall be considered as per IS: 875 (Part 2) 1987. Live load shall be

considered as 2.675 KN/m for the analysis and design.

Wind Load:

The basic wind speed and design velocity which shall be modified shall be taken

As per IS: 875 (Part 3) 1987.

As though this warehouse building is located within the area surrounded by high rise

apartments and buildings action of wind load is neglected as even the eave height is

limited only to 6m wind load is not considered.

63

4.2.2 DESIGN CODES

Following are the main design codes generally used:

AISC: American institute of steel construction manual

AISI: American iron and steel institute specifications

MBMA: Metal building manufacturer s code

ANSI: American national standards institute specifications

ASCE: American society of civil engineers

UBC: Uniform building code

IS: Indian standards (IS1893-2002 PART 1 FOR EQ) and (IS 875 PARTIII FOR

WIND)

4.3 DIMENSIONS OF THE WAREHOUSE

Width = 60 meters

Length = 15 Meters

Eave Height = 6 Meters

Bay Spacing = 6 Meters

Brick work = 2 Meters

Rise = 2m

Slope = 14.93 degree

64

Fig. 4.1 PLAN OF THE BUILDING

65

Fig. 4.2 ELEVATION OF THE BUILDING

Fig. 4.3.3 SIDE WALL ELEVATION OF THE BUILDING

66

4.4 DIMENSION OF ROOF

Area = 15 m 60 m

Span (l) = 15m

Rise (h) = 2m

Slope of the roof = tan-1 ( 2

7.5) = 14.930

= 14.930

Thus inclination of roof with horizontal = 14.930

4.4.1 Length of the rafter: (lr)

Lr = (height of the column) 2 + (rise) 2

Lr = (6)2 + (2)2

Lr = 7.76m

Actual length of the sheeting is likely more than this to cover eave girder

4.4.2 Number of purlins

Maximum allowable purlin spacing = 1400mm

Approximate number of purlin = 7762

1400

= 5.54 no’s

Place 6 number of purlin on each rafter @ 1290mm c/c

Spacing of purlins = 1.29 m

67

4.4.3 Loading calculation

4.4.4 Dead load:

Roofing material – GI sheeting with unit weight of 150 N/m2

Assuming unit weight of purlin as 100 N/m2

Total dead load = 150 + 100

= 250 N/m2

= 0.250 KN/m2

Dead load on plan area

= load bay spacing

= 0.25 6

= 1.5 KN/m

4.4.5 Live load:

As per IS 875 part 2 when slope is greater than or equal to 10 (i.e.) 10 then the

imposed load on the purlin is 750 N/m2 for every degree increase in slope in excess of

10 degree but not less than 400 N/m2

Live load = 750 -20 [14.93-10] = 651 N/m2

= 651 N/m2

2

3 rd. Load = 2

3 651 KN/m2

= 434.2 KN/m2

Live load on the plan area

= 434.2 6

= 0.4342 103

= 2.605 KN/m

68

69

4.5 DESIGN OF PURLINS

Span = 14 m

Length of the continuous purlin = 6 m

Spacing of purlin = 1290 mm

Slope of the roof = 14.93

The purlin is subjected to biaxial bending moment and as to design for different load

combinations and here as we exclude wind load only under live load and dead load

combination is designed

The following are the loads;

Wd = 1 KN

WL = 1.62 KN

And the components along the principal axes of the purlin are:

4.5.1 Dead load

Wdy = Wd cos

= 1 cos (14.93)

= 0.966 KN

Wdy = Wd sin

= 0.2574 KN

4.5.2 Live load

Wly = Wl cos

= 1.l2 cos (14.93)

= 1.566 KN

Wlx = wl sin

= 0.417 KN

The load combinations considered is D.L + L.L

The design bending moments are computed assuming that the purlins are continuous

and the maximum (absolute) bending moment occurs at the support.

70

4.5.3 Load Case: D.L + L.L

Mx1 = [10

DYW B +9

LYW B ]

= 0.966 1.566[ ] 6

10 9

= (0.9066 + 0.174) 6

Mx1 = 1.6236 KNm

My1 = [10

lYW B +9

WlxB ]

= 0.966 0.414[ ] 6

10 9

= (0.9066 + 0.046) 6

My1 = 0.8576 KNm

With these bending moment values on trying ISMC 75

Whose properties are Zx = 20.3cm3, Zy = 4.7 cm3

1 1MX MY

Zx Zy

1.62 0.85

20.3 4.7 KN/m2

Here = 180.85 N/m2

Here the stress is greater than the permissible stress

Hence not safe

Thus on trying ISMC 150

Zx = 103.9 103 mm, Zy = 9 103 mm

1 1MX MY

Zx Zy

71

1.62 0.85

103.9 9 KN/mm2

Here = 110.23 160 N/mm2

Thus the value is lesser than the permissible value 160 n/mm2

Hence it is safe.

Thus provide 6 no’s of ISMC 150 at 1.29m c/c

Fig. 4.5 STRUCTURAL PROPERTIES OF ISMC 150

Source: (IS 808: 1989)

72

4.6 DESIGN OF STEEL RAFTER

4.6.1 Total load

Dead load from sheeting = 150 N/m2

Self-weight of purlin = 100 N/m2

Total dead load = 250 N/m2

Spacing of purlins = 1.29 m

Dead load on each purlin = 0.250 1.29

Total dead load = 0.3225 KN/m

Factored dead load = 1.5 0.3225 = 0.4837 KN/m

Live load = 2.6052 KN/m

Factored live load = 1.5 0.26052 = 3.9078 KN/m

Total working load = 1.5 6 = 9 KN/m

Total factored load = 1.5 9 = 13.5 KN/m

LENGTH OF RAFTER (L) =7.76 m

Design moment M = 2

8

Wl

M = 1.6875 7.762

M = 101.67 KNm

Design shear V = 2

Wl

V = 6.75 7.76

V = 52.38 KN

Section modulus required = M

Fy ym0

Z p =

101.67

250 1.1 10 6

Zp = 447.348 10 3 mm3

On trying ISMB 400 which has Section modulus of Zp= 1176.168 10 3 mm3.

73

4.6.2 Properties of the section:

Depth of the section h = 400 mm

Width of the flange b = 140mm

Section area a = 7845.58mm2

Thickness of the flange tf = 16mm

Thickness of the web tw = 8.9 mm

Depth of web d = h-2 (h/2) = 400 – 2 (32.8)

= 333.4 mm

Moment of inertia about Z – Z axis

IZZ = 20438.4 10 4 mm4

Elastic section modulus

Ze = 1022.7 10 3 mm4

Outstanding leg of compression flange

B = 140 /2 = 70

4.6.3 SECTION CLASSIFICATION

= (250 /fy)1/2 = (250 /250 )1/2 = 1

B/Tf = 70 /16 = 4.38 9.5

D/TW = 333.4 /8.9 = 37.57 84

Hence the section is classified as plastic section

4.6.4 CHECK FOR SHEAR STRENGTH

Design shear

V = 27.37 KN

Design shear strength of the section,

74

13

1.1

13

1.1

250400 8.9

13

1.1

467728

467.128 27.37

D

D W

D

D

D

y

y

V area

V

f

fh T

V

V N

V

Hence It Is Safe

4.6.5 Check for Moment Capacity

D/TW = 38.2 WHICH IS LESS THAN 67 , SINCE =1

Hence,

Md =

13

1.1

13

1.1

250400 8.9

13

1.1

467728

467.128 27.37

W

y

y

are

h

N

fa

fT

p = 1.1 since plastic section

Md = 1.0 1176.163 103

250 /1.1 1.2 1022.7 103250 /1.1

= 267 .310 10 6 278 .918 106

Md = 267.310 106 N-mm

Check for deflection, total working load = 12.8 4.5 = 17.3 N/mm

75

4.6.6 Check for deflection

45

384

wl

EI

4

4

5 17.3(8300)

2 105 20458.4 10

27.127mm

Permissible deflection for a beam in building

= Le/300

= 8300 / 300

= 27.67 mm

Hence the deflection is within the permissible limits

Hence it is Safe

Provide ISMB 400

TOTAL WORKING LOAD = L.L + D.L

= 12.8 4.5

= 17.3 N/mm

MINIMUM DEFLECTION =

4

5 4

6.903×7.43 5δ=

2×20458.4×10 ×10 584

20.127mm

Le/300 = 27.76 ,6

20.127 27.67

Hence it is safe

Thus provide ISMB 400 604.3 N/m

76

4.7 Design of Column

4.7.1 Design stress

2

6

= factored load + factored live load + self weight of the beam

= 0.4837 + 3.96 + 0.604

= 4.9877 6

= 29.92 KN

125

NUse ISMB 400 @ 604.3

m

Area P

Column m

Load

Nfcd

mm

2rovided = 7846 mm.

Width of the Flange = 140 mm

Selecting 20 mm Plates , breadth required ' b ' is obtained from

2b ×t = 7846

7846 2b =

2

0

b = 196.15 mm

b; 200 mm

Thus provide 20mm × 200mm plates

Check for Over Hang :

140 Over Hang = 200 - = 3 p 12 t

20

Total Area Provided :

A = 7846 + 200 + 20 × 2

2 A = 15846 mm.

77

NFor ISMB 400 @ 604.3

m

4 4Izz = 2045.4 × 10 mm

2Iyy = 15846 mm

For the section selected

d t 2Izz = Izz + 2bt ( + )2 2

4 2Izz = 301.384 × 10 + 2 × 200 × 20 (100 + 10 )

6 4Izz = 301.384 × 10 mm

78

79

80

Fig. 4.6 BEARING TYPE OF CONNECTIONS

81

82

83

84

Figure 4.7. Beam To Column Connection

Figure 4.7.1 Beam to Column Connection

85

CHAPTER 5

ANALYSIS USING STAAD PRO

Fig. 5.1 Gable frame

Fig. 5.1 Cross Section of the Structure

86

Fig. 5.3 Displacement

Fig. 5.4 Displacement

87

Fig. 5.5 bending moment

Fig. 5.6 live load

88

Fig. 5.7 Dead load

89

Fig. 5.8 Sectional Properties of ISMB 400

90

CHAPTER 6

CONCLUSION

6.1 GENERAL:

Using of PEB instead of CSB may be reducing the steel quantity and thus reducing

the construction cost and Reduction in the steel quantity definitely reducing the dead

load. Reduction in the dead load reducing the size of Foundation. And reduction is all

but not the performance and life span is the unique property of pre- Engineered and

using PEB increase the Aesthetic view of structure

All the result values obtained on analyzing in this project proves to be economical and

the performance delivered by the pre – engineered building is higher than that of

conventional steel building and the results are as follows

6.2 Results:

Thus for the under taken project on pre-engineered building the results of the

components that were designed are as follows:

1. Roof Design : For The Area Of The Roof (A = 900mm2) Provide 6 No’s of

Purlin @ 1290mm C/C [4.4]

2. Purlin Design : Provide 6 No’s of ISMC 150 @ 1290 mm C/C [4.5]

3. Rafter Design : Provide ISMB 400 604.3 N/M [4.6]

4. Column Design : Provide ISMB 400 604.3 N/M With 20 200 mm Plates

[4.7]

5. Design Of Connections : Provide 12 No’s Of 20mm Diameter Bolts With The

Pitch Of 40 mm In Four Rows [4.8]

6. Design Of Gusset Plate : Provide ISA 125 95 [4.9]

91

7. Beam to column connection : [4.10]

1. Between Beam and Angles: Provide 100 100 8 mm Connecting Angles

with 3 No’s Of Rivets. [4.10.1]

2. Column Flanges: Provide 6 Rivets with 3 Rivet in Each Flange [4.10.2]

92

REFERENCE:

[1]. Aijaz Ahmad Zende, Prof. A. V. Kulkarni, Aslam Hutagi (Feb 2013).

Comparative Study of Analysis and Design of Pre-Engineered- Buildings and

Conventional Frames. IOSR Journal of Mechanical and Civil Engineering,

Volume 5, Issue.

[2]. C. M. Meera (June 2013). Pre-engineered building design of an industrial

warehouse. International journal of engineering sciences & emerging technologies.

Volume 5 Issue 2, pp: 75-82 Dr. Ramachandra & Virendra Gehlot “Design of Steel

Structures”

[3]. Design Concept of Pre-engineered Building by Syed Firoz1, Sarath Chandra

Kumar B1, and Design concept of pre-engineered building. International journal of

engineering research & applications, volume 2, issue 2, pp: 267-272

[4]. Design of Long span structures and Hangars by Amit Bharana ERA buildings

ltd.

[5] G. Sai Kiran, A. Kailasa Rao, R. Pradeep Kumar (Aug 2014). Comparison of

Design Procedures for Pre Engineering Buildings (PEB): A Case Study.

International Journal of Civil, Architectural, Structural & Contruction Engineering,

Volume 8, No. 4

[6]. http://www.engineeringcivil.com/pre-engineered-buildings.html

[7]. http://nbmcw.com/articles/PEB -roofing/PEB -prefab-steel-structures/18161-

preengineered-building-systems-a-promising-future.html

[8]. http://nbmcw.com/articles/PEB -roofing/PEB -prefab-steel-structures/18161-

preengineered-building-systems-a-promising-future.html

93

[9]. Introduction to Pre-engineered Steel Buildings

http://www.engineeringcivil.com/preengineered-buildings.html

[10]. IS: 800-2007: General Construction in Steel - Code of practice

[11]. IS: 875 (Part 1): - 1987 Code of Practice for Design Loads

[12]. IS: 875 (Part 2): - 1987 Code of Practice for Design Loads

[13]. IS: 875 (Part 3): - 1987 Code of Practice for Design Loads

[14]. Jatin D. Thakar, 2 Prof. P.G. Patel. Comparative study of pre- engineered

steel structure by varying width of structure. International journal of advanced

engineering technology, volume 4, issue3

[15]. N. Subramanian (2010) “Design of Steel Structures”

[16]. P. Dayaratnam “Design of Steel Structures”

[17]. Pre-engineered Metal Buildings < The Latest Trend in Building

Construction. By.K. Mitra Llyods Insulations Limited.12.

[18]. PEB VS Conventional the Zamil Steel Limited

[19]. S.S. Bhavikatti “Design of Steel Structures”

[20]. S. Ramamrutham “Design of Steel Structures”