ANALYSIS AND DESIGN OF MULTISTOREY BUILDING

A PROJECT REPORT Submitted in partial fulfillment of the requirements for the award of the degree of BACHELOR OF TECHNOLOGY in CIVIL ENGINEERING By AVINASH SHARMA DHRUV GUPTA GAURAB PAUL (1010930013) (1010930017) (1010930018)

Under the guidance of Mr. PRADEEP KUMAR

DEPARTMENT OF CIVIL ENGINEERING SRM INSTITUTE OF MANAGEMENT AND TECHNOLOGY SRM UNIVERSITY NCR CAMPUS, GHAZIABAD, U.P., INDIA May, 2013

SRM INSTITUTE OF MANAGEMENT AND TECHNOLOGY SRM UNIVERSITY NCR CAMPUS, GHAZIABAD, U.P., INDIA DEPARTMENT OF CIVIL ENGINEERING

CANDIDATES DECLARATION I hereby certify that the work which is being presented in the thesis entitled, ANALYSIS AND DESIGN OF MULTISTOREY BUILDING in partial fulfillment of the requirements for the award of the degree of Bachelor of Technology in Civil Engineering at SRM Institute of Management and Technology, NCR Campus, Ghaziabad is an authentic work carried out during a period from January, 2013 to May 2013 under the supervision of Mr. Pradeep Singh. The matter embodied in the thesis has not been submitted to any other University/Institute for the award of any Degree or Diploma.

(Avinash Sharma)

(Dhruv Gupta)

(Gaurab Paul)

Prof. (Dr.) Manoj Kumar Pandey (Director)

Dr. Vineet Bajaj (Head of Department)

Mr. Pradeep Kumar (Project Guide)

(Project Co-ordinater)

(External Examiner)

ACKNOWLEDGEMENT

I would like to express my gratitude to all the people behind the screen who helped me to transform an idea into a real application.

I profoundly thank Dr. Vineet Bajaj, Head of the Department, Civil Engineering who has been an excellent guide and also a great source of inspiration to my work.

I would like to thank my guide, Mr. Pradeep Kumar, Asst. Professor, for his technical guidance, constant encouragement and support in carrying out my project at college.

I would like to thank Mr. Ashoka Kumar, Staad Pro Expert from Bentley, for his valuable guidance in whenever requirement for the successful fulfillment of my project needs.

I wish to thank Er. Naveen Kumar Singh, Structural Consultant, for his valuable guidance in the practical aspects related to the project.

The satisfaction and euphoria that accompany the successful completion of the task would be great but incomplete without the mention of the people who made it possible with their constant guidance and encouragement crowns all the efforts with success. In this context I would like to thank my friends who supported me in successfully completing this project.

Thanking You.

AVINASH SHARMA 1010930013 DHRUV GUPTA 1010930017 GAURAB PAUL 1010930018

ABSTRACT

In this growing world, as a Civil Engineering student one needs to be fully aware of the Structural elements and their safety parameters before and during the execution of the project. As a sequel to this an attempt has been made to learn the process of analysis and design of a multistorey Building using Limit State Method (IS 456:2000). The project focuses on Reinforced Concrete buildings. The design using Limit State Method (of collapse and serviceability) is taken up. In the limit state of collapse, the strength and stability of structure is ensured. The guidelines being followed are as per IS 456:2000 and IS 13920 : 1993. The structural components in a typical multi storey building, consists of floor system which transfers the floor loads to a set of plane frames in one or both directions. The design study comprises of the footing, columns, beams and slabs.

The present project deals with the analysis of a multi-storey residential hostel building of G+9 consisting of 22 rooms in each floor at SRM University, NCR Campus. The loadings are applied and the design for beams, columns, slabs and footings is obtained.

STAAD Pro with its new features surpassed its predecessors and compotators with its data sharing capabilities with other major software like AutoCAD, and MS Excel.

The conclusion of this study is that the design parameters of a multi-storey building are successfully construed and Staad Pro is a very powerful tool which can save much time and is very accurate in Designs.

CONTENTS List of Tables List of Figures Assumptions and Notations Symbols CHAPTER 1 CHAPTER 2 2.1 2.2 2.3 2.4 i ii-iii iv-v vi-vii

INTRODUCTION LITERATURE SURVEY

1-2 3-12 4 7-9 9-11 12 13-17 14 15 15 16 17 18-20 19 20 21-38

Elements of Structural Design Design Philosophies Multi-Storey Building Structural Planning COMPUTER AIDED ANALYSIS & DESIGN

CHAPTER 3 3.1 3.2 3.3 3.4 3.5

Staad Pro V8i Alternatives for Staad Pro Staad Editor Staad Foundation V8i Auto Cad PLAN & ELEVATION

CHAPTER 4 4.1 4.2 Plan

Elevation LOADS

CHAPTER 5

5.1 5.2 5.3 5.4

Load Conditions and Structural System Response Building Loads Categorized by Orientation Design Load for the Residential Building Design Imposed Loads for Earthquake forces Calculation 5.4.1 Seismic Loading in Staad Pro V8i

22 22-23 24-30 31-35 32-33 35-36 37-38 39-54 40-42 43 43 44-47 48-54 55-105 56 57-63 64-71 72-86 87-105 106-108

5.5 5.6

Load Combinations Inputs to Staad Editor for Loadings ANALYSIS

CHAPTER 6 6.1 6.2 6.3 6.4 6.5

Methods of Analysis Seismic Analysis Procedure Analysis using Staad Pro V8i Analysis Results for Load Cases 1 to 4 Analysis Results for Support Reactions DESIGN

CHAPTER 7

Input to Staad Editor for Design 7.1 7.2 7.3 7.4 Beams Columns Slabs Foundation

CONCLUSION

APPENDICES APPENDIX A APPENDIX B REFERENCES 109 110 111

LIST OF TABLES Table No. 5.1 7.1 7.2 7.3 7.4 7.5 Zone Factor Dimensions of Continuous Strip Footing Design Results of Foundation Applied Loads-Allowable Stress Level Calculated Pressure at Four Corners Check for Stability against Overturning Title Page No. 30 92 93 95 96 96

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LIST OF FIGURES Figure No. 5.1 5.2 5.3 5.4 5.5 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 7.10 7.11 7.12 7.13 Title Dead Load on the Structure Live Load on the Structure Seismic Parameters Seismic Load in X direction (SLX) Seismic Load in Z direction (SLZ) Location of Beam No. 1 in the Structure Beam Reinforcement Beam Web Reinforcement Skeleton Structure showing Column No. 1539 Shear Bending for Column No. 1539 One Way Slab Load Distribution in a One Way Slab Two Way Slab Load Distribution in a Two Way Slab Load Distribution showing One Way and Two Way Monolithic connection between Slab, Beam & Column Plan showing Slabs Detailing of Slabs Page No. 25 27 33 34 35 59 60 61 68 70 72 73 73 74 74

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7.14 7.15 7.16 7.17 7.18 7.19 7.20 7.21 7.22 7.23 7.24 7.25 A-1 A-2

Staad Foundation Page showing Foundation Zoom View of Foundation Concrete and Rebar Parameters Cover and Soil Parameters Footings Dimensions Plan of Footings Elevation of Footings Strip Footing, FC1 Strip Footing, FC2 Strip Footing, FC3 Strip Footing, FC4 Strip Footing, FC5 Plan of the Multistorey SRM Hostel Building Elevation of the Multistorey SRM Hostel Building

89 89 90 90 91 102 102 103 103 104 104 105 109 110

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ASSUMPTIONS AND NOTATIONS

The notations adopted throughout the work are same IS-456-2000.

Assumptions in Design: 1.Using partial safety factor for loads in accordance with clause 36.4 of IS-456-2000 as t=1.5 2.Partial safety factor for material in accordance with clause 36.4.2 is IS-456-2000 is taken as 1.5 for concrete and 1.15 for steel. 3.Using partial safety factors in accordance with clause 36.4 of IS-456-2000 combination of load.

D.L+L.L. D.L+L.L+E.L

1.5 1.2

Density of materials used:

MATERIAL: DENSITY i) Plain concrete ii) Reinforced iii) Flooring material (c.m) iv) Brick masonry v) Fly ash 24.0KN/m3 25.0KN/m3 20.0KN/m3 19.0KN/m3 5.0KN/m3

4.LIVE LOADS: In accordance with IS. 875-86 i) Live load on slabs ii) Live load on passage iii)Live load on stairs 20.0KN/m2 4.0KN/m2 4.0KN/m2

DESIGN CONSTANTS: Using M30 and Fe 415 grade of concrete and steel for beams, slabs, footings, columns. Therefore:-

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fck fy

Characteristic strength for M30-30N/mm2 Characteristic strength of steel-415N/mm2

Assumptions Regarding Design:

i) Slab is assumed to be continuous over interior support and partially fixed on edges, due to monolithic construction and due to construction of walls over it. ii) Beams are assumed to be continuous over interior support and they frame in to the column at ends.

Assumptions on design:1) M20 grade is used in designing unless specified. 2) For steel Fe 415 is used for the main reinforcement. 3) For steel Fe 415 and steel is used for the distribution reinforcement. 4) Mild steel Fe 230 is used for shear reinforcement.

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SYMBOLS

The following symbols have been used in our project and its meaning is clearly mentioned respective to it: A Ast b D DL d1 D Mu,max Fck Fy Ld LL Lx Ly B.M. Mu Md Mf Mx My Mx My pt W Wd Tc max Tv Area Area of steel Breadth of beam or shorter dimension of rectangular column Overall depth of beam or slab Dead load Effective depth of slab or beam Overall depth of beam or slab Moment of resistance factor Characters tic compressive strength Characteristic strength of of steel Devlopment length Live load Length of shorter side of slab Length of longer side of slab Bending moment Factored bending moment Design moment Modification factor Mid span bending moment along short span Mid span bending moment along longer span Support bending moment along short span support bending moment along longer span Percentage of steel Total design load Factored load Maximum shear stress in concrete with shear Shear stress in concrete

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Tv Pu Mu,lim Mux, Muy

Nominal shear stress Diameter of bar Factored axial load Limiting moment of resistance of a section without compression reinforcement Moment about X and Y axis due to design loads

Mux1, Muy1 Maximum uniaxial moment capacity for an axial load of pu,bending moment X and Y axis respectively Ac Asc SLX SLZ Area of concrete & Area of longitudinal reinforcement for column Seismic Load in X direction Seismic Load in Z direction

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CHAPTER 1 INTRODUCTION

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Building construction is the engineering deals with the construction of building such as residential houses. In a simple building can be define as an enclose space by walls with roof, food, cloth and the basic needs of human beings. In the early ancient times humans lived in caves, over trees or under trees, to protect themselves from wild animals, rain, sun, etc. as the times passed as humans being started living in huts made of timber branches. The shelters of those old have been developed nowadays into beautiful houses. Rich people live in sophisticated condition houses. Buildings are the important indicator of social progress of the county. Every human has desire to own comfortable homes on an average generally one spends his two-third life times in the houses. These are the few reasons which are responsible that the person do utmost effort and spend hard earned saving in owning houses. Nowadays the house building is major work of the social progress of the county. Daily new techniques are being developed for the construction of houses economically, quickly and fulfilling the requirements of the community engineers and architects do the design work, planning and layout, etc. of the buildings. Draughtsman is responsible for doing the drawing works of building as for the direction of engineers and architects. The draughtsman must know his job and should be able to follow the instruction of the engineer and should be able to draw the required drawing of the building, site plans and layout plans etc., as for the requirements. A building frame consists of number of bays and storey. A multi-storey, multi-paneled frame is a complicated statically intermediate structure. A design of R.C building of G+9 storey frame work is taken up. The building in plan consists of columns built monolithically forming a network. It is residential complex. The design is made using software on structural analysis design (STAAD PRO V8i). The building subjected to both the vertical loads as well as horizontal loads. The vertical load consists of dead load of structural components such as beams, columns, slabs etc. and live loads. The horizontal load consists of the wind forces thus building is designed for dead load, live load and wind load as per IS 875. The building is designed as two dimensional vertical frame and analyzed for the maximum and minimum bending moments and shear forces by trial and error methods as per IS 456-2000. The help is taken by software available in institute and the computations of loads, moments and shear forces and obtained from this software.

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CHAPTER 2 LITERATURE SURVEY

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BACKGROUND WORK (LITERATURE SURVEY) 2.1 Elements of Structural Design Structures in concrete have become very common in civil engineering construction. Concrete has established itself to be a universal building material because of its high compressive strength and its adaptability to take any form and shape. Its low tensile strength is compensated by the use of steel reinforcement. Thus, the concrete is strengthened(i.e. reinforced) by steel and the resultant composite mass is known as Reinforced Cement Concrete (R.C.C.) It is this combination which allows almost unlimited use of reinforced concrete in construction of buildings, bridges, tanks, dams etc., with the result that almost every civil engineer is intimately concerned with reinforced concrete (R.C.) structures. It is therefore, necessary that every civil engineer knows the basic principles involved in design of R.C. structures. So, it will be approximate to begin by reviewing the basic principles of structural design in general and then its application to reinforced concrete structures. 2.1.1. Engineering Structure and Structural Design An engineering structure is an assembly of members or elements transferring load (or resisting the external actions) and providing a form, space, an enclose and/or cover to serve the desired function. Structural design is a science and art of designing, with economy and elegance, a durable structure which can safely carry the design forces and can serve the desired function satisfactorily in working environment during its intended service life span. 2.1.2. Objectives and Basic Requirements of Structural Design The objective of the structural design is to plan a structure which meets the basic requirements of structural science and those of the client or the user. The basic requirements of the structural design are as follows: i. Safety: It has been the prime requirement of structural design right from the history of civilization and construction that a structure shall be so designed that it will not collapse in any way during its expected life span. Safety of structure is achieved by adequate

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ii.

strength and stability. Besides strength, ductility of structure is also nowadays considered to be an additional desired quality from a view point that if at all failure occurs, it should not be sudden but should give prior warning of its probable occurrence so as to enable one to minimize the consequences of collapse and avoid loss of human life. Ductility is thus obtained by providing steel of such quality that it would yield prior to crushing of concrete.

iii.

Serviceability: The structure shall efficiently serve the intended function and also shall give a satisfactory performance throughout the life span. The performance is rated buy the fitness of the structure to maintain deflections, deformations, cracking and vibration effects within acceptable limits. It is achieved by providing adequate stiffness and cracking resistance.

iv.

Durability: The structure shall resist effectively environmental action during its anticipated exposure conditions, such as rain, alternate wetting and drying or freezing, climatic variations in temperature and humidity, chemical actions of salt, abrasion action etc.

v.

Economy: The economy shall be of material by optimum utilization of its strength or it may be the economy of cost which includes cost of construction as well as cost of maintenance and repairs.

vi.

Aesthetics: The structure should be so designed that it should not only be safe, serviceable and durable but should also give a pleasing appearance without affecting the economy to a great extent.

vii.

Feasibility, Practicability and Acceptability: The structure has to be so designed that the proposed solution is feasible, practicable an acceptable.

2.1.3. The Design Process: The entire process of design requires conceptual thinking, sound knowledge of engineering, relevant design codes and byelaws, backed up by experience, imagination and judgment. The codes of practice are compendia of good practice drawn by experienced and competent engineers. They are intended to guide the engineers and should not be allowed to replace their conscience and competence.

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The design process commences with the planning of the structure primarily to meet its functional requirement and then designed for safety and serviceability. Thus, the design of any structure is categorized into the following two types: 1) Functional Design: The structure to be constructed must primarily serve the basic purpose for which it is to be constructed to satisfy the need of the user efficiently. This includes proper arrangement of rooms, halls, good ventilation, and acoustics, unobstructed view in cinema theatre / community halls, proper water supply and drainage arrangements etc. 2) Structural Design: As mentioned earlier Structural design is a science and art of designing, with economy and elegance, a durable structure which can safely carry the design forces and can serve the desired function satisfactorily in working environment during its intended service life span. It consists of the following steps: a) Structural Planning b) Determination of Loads c) Analysis d) Member Design e) Drawing, Detailing and Preparation of Schedule. 2.1.4. Elements of a R.C. Building Frame The principle elements of a R.C. building frame are slab, beam, column and footing. a) Slab: It is two-dimensional or a planar member supporting a transverse load and providing a working floor or a covering shelter. The loads are transferred to supporting beams or walls in one or both directions. b) Beam: A Beam is a one-dimensional (normally horizontal) flexural member which provides support to the slab and the vertical walls. c) Column: It is one dimensional vertical member providing a support to beam. Load is transferred primarily by axial compression accompanied by bending and shear.

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d) Footing: A footing can be considered as a horizontal two way cantilever slab providing a wide base to a column for distributing concentrated column load over a large area of supporting soil. Load transfer is affected partly by bending and partly by bearing. 2.1.5. Computer Programming It is important to emphasize that in every field the use of computer prevails. Access to personal computers, due to their affordable cost, has made it possible for almost every engineer and student to be equipped with such tools. The need is more apparent to utilize this powerful tool for simplifying engineering design works. It has now become practically obligatory for structural engineers or students to get conversant with the programming languages and techniques of computer aided design. 2.2. Design Philosophies

Since the inception of the concept of reinforced concrete in the last twenties of the nineteenth century, the following design philosophies have been evolved for design of R.C. structures: a) Working Stress Method (WSM) b) Ultimate Load Method (ULM) c) Limit State Method (LSM) 2.2.1. Limit State Method (LSM) The limit state method ensures the safety at ultimate load and serviceability at working load rendering the structure fit for its intended use. Thus, it considers the fitness of the structure to perform its function satisfactorily during its life span. The salient features and the merits of the method are briefly given below: 1) It considers the actual behavior of the structure during the entire loading history up to collapse. 2) It adopts the concept of fitness of structure to serve the desired function during the service life span and defines the limiting state of fitness as the limit state. 3) It attempts to define quantitatively the margins of safety or fitness on some scientific mathematical foundations rather than on adhoc basis of experience and judgment.

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The mathematical basis is derived from classical reliability theory and statistical probability (e.g. the reliability of the fitness of the structure and the probability of attainment of a critical limit state). 4) The method, adopts the idea of probability of the structure becoming unfit, and attempts to achieve the minimum acceptable probability of failure. 5) The method is based on statistical probabilistic principles. The method examines the factors which can be quantified by statistical method (such as loads, material strength) and then they are accounted through characteristic loads and characteristic strength on the basis of statistical probabilistic principles and the others which are abstract (such as variation in dimensions, accuracy, variation in loads and material properties etc.) are taken into account through partial safety factors. In the limit state method, a structure is essentially designed for safety against collapse (i.e. for ultimate strength to resist ultimate load) and checked for its serviceability at working loads. The first part of design thus incorporates basic principles of ultimate load method. But at the same time, it eliminates the drawbacks of the ultimate load method by introducing the second part of check for serviceability. Since this second part relates to working loads at which the behavior of structure is elastic, the material uses the principles of working stress method to satisfy the requirements of serviceability. The limit state method, thus, makes a judicious combination of the ultimate load method and working stress philosophy avoiding the demerits of both. 2.2.2. Limit State of Collapse (Ultimate Limit State) It is the limit state on attainment of which the structure is likely to collapse. It relates to stability and ultimate strength of the structure. Design to this limit state ensures safety of structure from collapse. The structure failure can be any of the following types: i. Collapse of one or more members occurring as a result of force coming on the member exceeding its strength(Types (a) and (b) given below);

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ii.

Displacement of the structure bodily due to lack of equilibrium between the external forces and the resisting reactions (Types (c), (d), (e) given below).

The various conditions leading to structural failure are as follows: a) Failure, breakage and hence division into segments of one or more members of the structure either due to material failure or on account of formation of mechanism by development of plastic hinges at one or more critical sections. b) Buckling; c) Sliding; d) Overturning; e) Sinking. This limit state is attended to by providing resistance greater than the force coming on it and keeping a margin of safety through safety factors. I.S. Code prescribes different safety factors for overturning and sliding without giving any special status to sinking or buckling. 2.2.3 Limit State of Serviceability Limit states of serviceability relate to performance or behavior of structure at working loads and are based on causes affecting serviceability of the structure. They are mainly subdivided into following categories: A. Limit State of Deflection, B. Limit State of Cracking, and C. Other Limit States. 2.3. MULTISTOREY BUILDINGS

Reinforced concrete buildings consist of floor slabs, beams, girders and columns continuously placed to form a rigid monolithic system. This continuous system leads to greater redundancy, reduced moments and distributes the load more evenly. The floor slab may rest on a system of interconnected beams. A building frame is a three dimensional structure or a space structure.

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A wide range of approaches have been used for buildings of varying heights and importance, from simple approximate methods which can be carried out manually, or with the aid of a pocket calculator, to more refined techniques involving computer solutions. Till a few years ago most of the multistory buildings were analyzed by approximate methods such as substitute frame, moment distribution, portal and cantilever methods. The recent advancement of abundance of ready-made computer package programs has reduced the use of approximation methods. This has been induces from analysis to design, to plotting, to detaining, to specification writing, to cost estimating, etc.

2.3.1. Structural Systems

A building is subjected to several loads which are transferred to ground through a system of interconnected structural members. In tall buildings, the biggest challenge comes from controlling lateral displacements within the serviceability limit state. The lateral stiffness may be achieved through a permutation and combination of placement of columns and walls in plan. A structural system may be classified as follows:1. Load Bearing wall system: Walls provide support for all gravity loads as well as resistance to lateral loads. No columns. The Walls and partition wall supply in-plane lateral stiffness and stability to resist wind and earthquake loads. Clause 8.2.1 and 8.4.8 of IS: 4326-1993 restricts the use of such system to 3 storey in seismic zone V and 4 storey in other zone.

2. Building with flexural (shear) wall system: Gravity load is carried by frame supported on columns rather than on bearing walls. The frame provides vertical stability to the building and prevents collapse after damage to flexural wall or braced frames.

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3. Moment resisting frame system: Members and joints are capable of resisting vertical and lateral loads primarily by flexure. Relative stiffness of girders and columns is very important. A frame can be designed using weak column-strong girder proportions or strong column-weak girder proportions. 4. Flexural (shear) wall system: Reinforced concrete wall designed to resist lateral forces parallel to the plane of the wall and detailed to provide ductility as per IS 13920-1993. The America IBC 2000 permits use of flexural (shear) wall system up to 45m high. However it can be used up to 70m; if and only if, shear walls in any plane do not resist more than 33% of earthquake design force including torsional effects.

5. Dual frame system: Moment resisting frame providing support for gravity loads. Resistance to lateral loads by: Special detailed moment resisting frame (concrete or steel) which is capable of resisting at least 25%of base shear including torsional effects. Flexural walls i.e. shear walls or braced frames must resist total required lateral loads. 6. Space frame: 3-Dimensional structural system without shear or bearing walls composed of interconnected members laterally supported

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2.4.

Structural Planning

Salient features:

Utility of building No of stories No of staircases No. of Rooms/floor No of lifts Type of construction Types of walls Ventilation

Residential Hostel Building G+9 1 22 rooms on each floor with attached washroom. 1 R.C.C framed structure Brick wall Ventilated rooms with window in each room.

Geometric details: Ground floor Floor to floor height Height of plinth Depth of foundation 2m 3.65m. 2m 2m

Materials: Concrete grade All steel grades Bearing capacity of soil: Depth of Water Table M35 (for footing) & M25 (for all other elements) Fe415 grade 175KN/m2 4m.

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CHAPTER 3 COMPUTER AIDED ANALYSIS & DESIGN

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COMPUTER AIDED ANALYSIS AND DESIGN This project is mostly based on software and it is essential to know the details about these softwares. List of softwares used 1. Staad Pro (V8i) 2. Staad foundations 5(V8i) 3. Auto Cad 2010

STAAD PRO V8i

STAAD FOUNDATIONV8i

AUTOCAD 2010

3.1.

STAAD PRO V8i

Staad Pro V8i is powerful design software licensed by Bentley .Staad stands for structural analysis and design Any object which is stable under a given loading can be considered as structure. So first find the outline of the structure, whereas analysis is the estimation of what are the type of loads that acts on the beam and calculation of shear force and bending moment comes under analysis stage. Design phase is designing the type of materials and its dimensions to resist the load. This we do after the analysis. To calculate S.F.D and B.M.D of a complex loading beam it takes about an hour. So when it comes into the building with several members it will take a week. Staad pro is a very powerful tool which does this job in just an hours staad is a best alternative for high rise buildings. Nowadays most of the high rise buildings are designed by staad which makes a compulsion for a civil engineer to know about this software. This software can be used to carry RCC, steel, bridge, truss etc. according to various country codes.

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3.2.

Alternatives for Staad Pro V8i:

STRUDS, ETAB, ROBOT, SAP which gives details very clearly regarding reinforcement and manual calculations. But these softwares are restricted to some designs only whereas Staad can deal with several types of structure.

3.3.

Staad Editor:

Staad has very great advantage to other softwares i.e., Staad editor. Staad editor is the programming For the structure we created and loads we taken all details are presented in programming format in Staad editor. This program can be used to analyze other structures also by just making some modifications, but this require some programming skills. So load cases created for a structure can be used for another structure using Staad editor.

Limitations of Staad Pro V8i: 1. Huge output data 2. Even analysis of a small beam creates large output. 3. Unable to show plinth beams.

3.4. Staad foundation: Staad foundation is a powerful tool used to calculate different types of foundations. It is also licensed by Bentley softwares. All Bentley softwares cost about 10 lakhs and so all engineers cant use it due to heavy cost. Analysis and design carried in Staad and post processing in Staad gives the load at various supports. These supports are to be imported into this software to calculate the footing details i.e., regarding the geometry and reinforcement details. This software can deal different types of foundations SHALLOW (D

DEEP (D>B) 1.Pile Cap 2. Driller Pier 1. Isolated footing is spread footing which is common type of footing. 2. Combined Footing or Strap footing is generally laid when two columns are very near to each other. 3. Mat foundation is generally laid at places where soil has less soil bearing capacity. 4. Pile foundation is laid at places with very loose soils and where deep excavations are required. So depending on the soil at type we have to decide the type of foundation required. Also lot of input data is required regarding safety factors, soil, materials used should be given in respective units. After input data is give software design the details for each and every footing and gives the details regarding 1. Geometry of footing 2. Reinforcement 3. Column layout 4. Graphs 5. Manual calculations These details will be given in detail for each and every column. Another advantage of foundations is even after the design; properties of the members can be updated if required. The following properties can be updated Column Position Column Shape Column Size Load Cases Support List It is very easy deal with this software and we dont have any best alternative to this.

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3.5.

AutoCAD:

AutoCAD is powerful software licensed by auto desk. The word auto came from auto Desk Company and cad stands for computer aided design. AutoCAD is used for drawing different layouts, details, plans, elevations, sections and different sections can be shown in auto cad. It is very useful software for civil, mechanical and also electrical engineer. The importance of this software makes every engineer a compulsion to learn this softwares. We used AutoCAD for drawing the plan, elevation of a residential building. We also used AutoCAD to show the reinforcement details and design details of a stair case. AutoCAD is a very easy software to learn and much user friendly for anyone to handle and can be learn quickly. Learning of certain commands is required to draw in AutoCAD.

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CHAPTER 4 PLAN & ELEVATION

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4.1.

PLAN

The Annexure A represents the plan of a G+9 hostel building. The plan clearly shows that it is a combination of rooms and attached washrooms of the SRM Hostel building. The Hostel is located at SRM University, NCR Campus, Ghaziabad which is surrounded by other hostel blocks on the three sides except the backside. Every floor consists of 22 rooms along with attached bathroom. It represents a spacious surrounding with huge areas for each room. It is a G+9 proposed building, so for 9 floors we have 9*22=198 rooms. The plan shows the details of dimensions of each and every room. The entire plan area is about 810sq.m. The plan also gives the details of location of stair cases in different blocks. We have 2 stair cases for the building and designing of stair case is shown in AutoCAD plot no.3.

At the left end of the building we have a small construction which consists of two lifts and those who want to fly through lift can use this facility and we know for a building with more than G+4 floors should compulsory have lift and the charges for the facilities is collected by all the members. So these represent the plan of our building and detailed explanation of remaining parts like elevations and designing is carried in the next sections.

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4.2.

Elevation

The Annexure B represents the proposed elevation of building. It shows the elevation of the G+9 building representing the front view which gives the overview of a building block. Each floor consists of height 3m which is taken as per GHMC rules for residential buildings. The building is not designed for increasing the number of floors in future.so the number of floors is fixed for future also for this building due to unavailability of the permissions of respective authorities. Also special materials like fly ash and self-compacted concrete were also used in order to reduce the dead load and increase life of the structure and also improve economy. But these materials were not considered while designing in Staad to reduce the complexity and necessary corrections are made for considering the economy and safety of the structure as it is a very huge building. The construction is going to complete in the month of July 2013 and ready for the occupancy. This is regarding the elevation and details of the site and next section deals with the design part of the building under various loads for which the building is designed.

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CHAPTER 5 LOADS

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LOADS 5.1. Load Conditions and Structural System Response:

The concepts presented in this section provide an overview of building loads and their effect on the structural response of typical R.C.C structures. As shown in Table, building loads can be divided into types based on the orientation of the structural action or forces that they induce: vertical and horizontal (i.e. lateral) loads. Classification of loads is described in the following sections.

5.2.

Building Loads Categorized by Orientation:

Types of loads on a hypothetical building are as follows. Vertical Loads Dead Load (gravity) Live (gravity) Snow (gravity) Wind (uplift on roof) Seismic and wind (overturning) Seismic (vertical ground motion)

5.2.1. Horizontal (Lateral) Loads: Direction of loads is horizontal w.r.t to the building. Wind Seismic (horizontal ground motion) Flood (static and dynamic hydraulic forces Soil (active lateral pressure)

5.2.2. Vertical Loads: Gravity loads act in the same direction as gravity (i.e., downward or vertically) and include dead, live, and snow loads. They are generally static in nature and usually considered a uniformly distributed or concentrated load. Thus, determining a gravity load on a beam or column is a relatively simple exercise that uses the concept of tributary areas to assign loads to structural elements, including the dead load (i.e., weight of the construction) and any applied loads(i.e.,

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live load). For example, the tributary gravity load on a floor joist would include the uniform floor load (dead and live) applied to the area of floor supported by the individual joist. The structural designer then selects a standard beam or column model to analyze bearing connection forces (i.e., reactions) internal stresses (i.e., bending stresses, shear stresses, and axial stresses) and stability of the structural member or system a for beam equations. The selection of an appropriate analytic model is, however no trivial matter, especially if the structural system departs significantly from traditional engineering assumptions are particularly relevant to the structural systems that comprise many parts of a house, but to varying degrees. Wind uplift forces are generated by negative (suction) pressures acting in an outward direction from the surface of the roof in response to the aerodynamics of wind flowing over and around the building. As with gravity loads, the influence of wind uplift pressures on a structure or assembly (i.e. roof) are analyzed by using the concept of tributary areas and uniformly distributed loads. The major difference is that wind pressures act perpendicular to the building surface (not in the direction of gravity) and that pressures vary according to the size of the tributary area and its location on the building, particularly proximity to changes in geometry (e.g., eaves, corners, and ridges).Even though the wind loads are dynamic and highly variable, the design approach is based on a maximum static load (i.e., pressure) equivalent. Vertical forces are also created by overturning reactions due to wind and seismic lateral loads acting on the overall building and its lateral force resisting systems, Earthquakes also produce vertical ground motions or accelerations which increase the effect of gravity loads. However, Vertical earthquake loads are usually considered to be implicitly addressed in the gravity load analysis of a light-frame building.

5.2.3. Lateral Loads: The primary loads that produce lateral forces on buildings are attributable to forces associated with wind, seismic ground motion, floods, and soil. Wind and seismic lateral loads apply to the entire building. Lateral forces from wind are generated by positive wind pressures on the windward face of the building and by negative pressures on the leeward face of the building, creating a combined push and-pull effect. Seismic lateral forces are generated by a structures dynamic inertial response to cyclic ground movement. The magnitude of the seismic shear (i.e., lateral) load depends on the

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magnitude of the ground motion, the buildings mass, and the dynamic structural response characteristics (i.e., dampening, ductility, natural period of vibration, etc.). For houses and other similar low rise structures, a simplified seismic load analysis employs equivalent static forces based on fundamental Newtonian mechanics (F=ma) with somewhat subjective (i.e., experiencebased) adjustments to account for inelastic, ductile response characteristics of various building systems. Flood loads are generally minimized by elevating the structure on a properly designed foundation or avoided by not building in a flood plain. Lateral loads from moving flood waters and static hydraulic pressure are substantial. Soil lateral loads apply specifically to foundation wall design, mainly as an out-of-plane bending load on the wall. Lateral loads also produce an overturning moment that must be offset by the dead load and connections of the building. Therefore, overturning forces on connections designed to restrain components from rotating or the building from overturning must be considered. Since wind is capable of the generating simultaneous roof uplift and lateral loads, the uplift component of the wind load exacerbates the overturning tension forces due to the lateral component of the wind load. Conversely the dead load may be sufficient to offset the overturning and uplift forces as is the case in lower design wind conditions and in many seismic design conditions.

5.3.

Design loads for the residential building:

General Loads are a primary consideration in any building design because they define the nature and magnitude of hazards are external forces that a building must resist to provide a reasonable performance(i.e., safety and serviceability) throughout the structures useful life. The anticipated loads are influenced by a buildings intended use (occupancy and function); configuration (size and shape) and location (climate and site conditions).Ultimately, the type and magnitude of design loads affect critical decisions such as material collection, construction details and architectural configuration. Since building codes tend to vary in their treatment of design loads the designer should, as a matter of due diligence, identify variances from both local accepted practice and the applicable

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code relative to design loads as presented in this guide, even though the variances may be considered technically sound.

5.3.1. Dead Loads: Dead loads consist of the permanent construction material loads compressing the roof, floor, wall, and foundation systems, including claddings, finishes and fixed equipment. Dead load is the total load of all of the components of the components of the building that generally do not change over time, such as the steel columns, concrete floors, bricks, roofing material etc. In staad pro assignment of dead load is automatically done by giving the property of the member. In load case we have option called self-weight which automatically calculates weights using the properties of material i.e., density and after assignment of dead load the skeletal structure looks red in color as shown in the figure.

Figure 5. 1

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Example for calculation of dead load: Dead load calculation Weight=Volume x Density Self-weight floor finish=0.12*25+1=3kn/m^2 The above example shows a sample calculation of dead load. Dead load is calculated as per IS 875 part 1

Here for the multistory building we need to define the loads distributed by the masonry brick wall which is shown in the above figure using UNI GY -20.063N/mm.

5.3.2. Imposed Loads

Live loads are produced by the use and occupancy of a building. Loads include those from human occupants, furnishings, no fixed equipment, storage, and construction and maintenance activities. As required to adequately define the loading condition, loads are presented in terms of uniform area loads, concentrated loads, and uniform line loads. The uniform and concentrated live loads should not be applied simultaneously n a structural evaluation. Concentrated loads should be applied to a small area or surface consistent with the application and should be located or directed to give the maximum load effect possible in endues conditions. For example, the stair load of 300 pounds should be applied to the center of the stair tread between supports. In staad we assign live load in terms of: Floor load = 2.125KN/m2 (as per IS 875 Part 2) (for residential building including floor finish) Plate/Element Load = 2KN/m2 (Imposed/live load on slab)

We have to create a load case for live load and select all the beams to carry such load. After the assignment of the live load the structure appears as shown below.

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Figure 5.2 Live loads are calculated as per IS 875 Part 2

5.3.3 Wind loads: In the list of loads we can see wind load is present both in vertical and horizontal loads. This is because wind load causes uplift of the roof by creating a negative (suction) pressure on the top of the roof figure 3 a diagram of wind load. Wind produces non static loads on a structure at highly variable magnitudes. The variation in pressures at different locations on a building is complex to the point that pressures may become too analytically intensive for precise consideration in design. Therefore, wind load specifications attempt to amplify the design problem by considering basic static pressure zones on a building representative of peak loads that are likely to be experienced. The peak pressures in one zone for a given wind direction may not, However, occur simultaneously in other zones. For some pressure zones, the peak pressure depends on an arrow range of wind direction. Therefore, the wind directionality effect must also be factored into determining risk consistent wind loads on buildings.

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Assignment of wind speed is quite different compared to remaining loads. We have to define a load case prior to assignment. After designing wind load can be assigned in two ways 1. Collecting the standard values of load intensities for particular heights and assigning of the loads for respective height. 2. Calculation of wind load as per IS 875 part 3. We designed our structure using second method which involves the calculation of wind load using wind speed. In Delhi we have a wind speed of 47 kmph for 10 m height and this value is used in calculation.

Basic wind speed: It gives the basic wind speed of India, as applicable to 1m height above means ground level for different zones of the country. Basic wind speed is based on peak just velocity averaged over a short time interval of about 3 seconds and corresponds to mean heights above ground level in an open terrain.

Design wind speed: The basic wind speed (Vb) for any site shall be obtained the following effects to get design wind velocity at any height (Vz) for the chosen structure. a) Risk level b) Terrain roughness, height and size of the structure and c) Local topography It can be mathematically expressed as follows: Vs. =Vb* K1* K2* K3 Where Vz= design wind speed at any height Z in m/s K1= probability factor (risk coefficient) K2=terrain height and structure size factor and K3=topography factor

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5.3.4. Earthquake Loads Earthquake or seismic load on a building depends upon its geographical location, lateral stiffness and mass, and is reversible. Its effect should be considered along both axes of a building taken one at a time. A force is defined as the product of mass and acceleration. During an earthquake, the mass is imparted by the building whereas the acceleration is imparted by ground disturbances. In order to have a minimum force, the mass of the building should be as low as possible. There can be no control on the ground acceleration as it is an act of God! The point of application of this internal force is the center of gravity of the mass on each floor of the building. Once there is a force, there has to be an equal and opposite reaction to balance the force. The inertial force is resisted by the building and the resisting force acts at the center of rigidity at each floor of the building or shear center of the building at each storey. There are two methods to determine the earthquake force in a building: a) Seismic coefficient method or static method. b) Response spectrum method or modal analysis method or spectral acceleration method or dynamic method. Response Spectra: The representation of the maximum response of idealized single degree of freedom system having certain period of vibration and damping during a given earthquake is referred to as a response spectrum. In the IS : 1893:2002 code, an elastic response spectrum has been proposed for the Maximum Considered Earthquake (MCE) condition.

NOTE: - The wind loads and earthquake loads are assumed not to act simultaneously. A building is designed for the worst of the two loads. The fact is that the design forces for wind are greater than the seismic design forces (i.e. wind governs the design) does not obviate the need for seismic detailing. While wind forces govern, the design must provide at least the type of seismic detailing that corresponds to the seismic forces calculated for that building. But for this structure the seismic loads are predominant than that of the wind loads, therefore, the seismic loads govern the design.

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Design Spectrum For the purpose of determining seismic forces, the country is classified into four seismic zones as shown in Fig. 1. of IS 1893 The design horizontal seismic coefficient Ah for a structure shall be determined by the following expression:

Ah= Z.I.Sa /2.R.g Provided that for any structure with T

5.4.

Design Imposed Loads for Earthquakes Force Calculation

For various loading classes as specified in IS 875(Part 2), the earthquake force shall be calculated for the full dead load plus the percentage of imposed load as given in Table 8. For calculating the design seismic forces of the structure, the imposed load on roof need not be considered. The percentage of imposed loads should be 25% for floor loads up to and including 3KN/m2.

Seismic Weight of Floors The seismic weight of each floor is its full dead load plus appropriate amount of imposed load. While computing the seismic weight of each floor, the weight of columns and walls in any storey shall be equally distributed to the floors above and below the storey.

Seismic Weight of Building The seismic weight of the whole building is the sum of the seismic weights of all the floors. Any weight supported in between storeys shall be distributed to the floors above and below in inverse proportion to its distance from the floors.

Design Lateral Force Buildings and portions thereof shall be designed and constructed, to resist the effects of design lateral force. The design lateral force shall first be computed for the building as a whole. This design lateral force shall then be distributed to the various floor levels. The overall design seismic force thus obtained at each floor level, shall then be distributed to individual lateral load resisting elements depending on the floor diaphragm action.

Design Seismic Base Shear The total design lateral force or design seismic base shear ( Vb)along any principal direction shall be determined by the following expression: Vb= AhW Where,

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Ah = Design horizontal acceleration spectrum value, using the fundamental natural period T, in the considered direction of vibration, and W = Seismic weight of the building.

5.4.1. Seismic Loading in Staad Pro V8i: Now since we know the basic criterion for earthquake loads, the seismic weights as assigned in Staad Pro V8i software are as follows: Defining Seismic parameters, which includes the following: Earthquake Zone for Delhi is Zone IV (i.e. Zone Factor = 0.24) Response Reduction Factor = 5, (for Special RC moment-resisting frame (SMRF) as per Table 7, IS 1893.) Importance Factor = 1.0, ( for All Other Buildings other than Important service and community buildings, such as hospitals; schools; monumental structures; emergency buildings like telephone exchange, television stations, radio stations, railway stations, fire station buildings; large community halls like cinemas, assembly halls and subway stations, power stations for which I = 1.5.) Response spectra for Rock and Soil Site Type (SS) = 2, (For Medium Type Soil at 5% damping.) Type of Structure = 1 (for Reinforced Concrete Framed Structure) Damping Ratio = 5% Depth of foundation = 2m

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Figure5.3 The weights are then defined for the structure which includes: SELFWEIGHT (represents the dead weight) FLOOR WEIGHT (represents the live load) PLATE WEIGHT (represents the live load on slab) MEMBER WEIGHT (masonry brick weight )

The load case for seismic loads is then defined in the two directions that are horizontally perpendicular (X and Z) directions. The figure of Staad Editor is shown as below:

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Figure5.4

Seismic Load in X direction (SLX)

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Figure5.55.5. LOAD COMBINATIONS

Seismic Load in Z direction (SLZ)

Load combinations as per IS 875 Part 5 are taken into consideration.

A judicious combination of the loads (specified in IS 875 Parts 1 to 4 of this standard and earthquake), keeping in view the probability of: a) Their acting together, and b) Their disposition in relation to other loads and severity of stresses or c) Deformations caused by combinations of the various loads are necessary to ensure the required safety and economy in the design of a structure. Load Combinations - The various loads should, therefore, be combined in accordance with the stipulations in the relevant design codes. In the absence of such recommendations, the following

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loading combinations, whichever combination produces the most unfavorable effect in the building, foundation or structural member concerned may be adopted ( as a general guidance ). It should also be recognized in load combinations that the simultaneous occurrence of maximum values of wind, earthquake, imposed and snow loads is not likely: -

1) DL + LL 2) DL + LL +SLX 3) DL + LL + SLZ 4) DL + LL SLX 5) DL + LL SLZ 6) 1.5 (DL + LL) 7) 1.5 (DL + SLX) 8) 1.5 (DL - SLX) 9) 1.5 (DL + SLZ) 10) 1.5 (DL -SLZ) 11) 0.9DL +1.5SLX 12) 0.9DL -1.5SLX 13) 0.9DL + 1.5SLZ 14) 0.9DL - 1.5SLZ 15) 1.2 (DL +LL +SLX 16) 1.2(DL +LL -SLX ) 17) 1.2(DL+LL+SLZ) 18) 1.2(DL + LL - SLZ) Where, the numerals 1.5, 0.9, 1.2, 1.0 represents the load factors as per IS 875 Part 5. DL = Dead Load LL = Live Load SLX = Seismic load in X direction SLZ = Seismic load in Z direction The negative sign in the above load combinations shows the directions opposite to the defined case.

Earthquake is not likely to occur simultaneously with wind or maximum flood or maximum sea waves. Since the wind velocity in the region is less and less dominant than the seismic zone (Zone IV), therefore wind load is not considered for design.

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5.7.

INPUT TO STAAD EDITOR FOR LOADING:

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CHAPTER 6 ANALYSIS

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ANALYSIS 6.1 Method Of Analysis

The various methods of analysis of statistically indeterminate portal frames are : 1. Method of flexibility coefficients. 2. Slope displacements methods (iterative methods) 3. Moment distribution method 4. Kanes method 5. Cantilever method 6. Portal method 7. Matrix method 8. Using STAAD Pro V8i

6.1.1 Method of flexibility coefficients: The method of analysis is comprises reducing the hyper static structure to a determinate structure form by: Removing the redundant support (or) introducing adequate cuts (or) hinges. Limitations: It is not applicable for degree of redundancy>3

6.1.2. Slope displacement equations: It is advantageous when kinematic indeterminacy

Iterative methods: These methods involve distributing the known fixed and moments of the structural member to adjacent members at the joints in order satisfy the conditions of compatibility. Limitations of hardy cross method: It presents some difficulties when applied to rigid frame especially when the frame is susceptible to side sway. The method cannot be applied to structures with intermediate hinges. 6.1.3 Kanis method: This method over comes some of the disadvantages of hardy cross method. Kanis approach is similar to H.C.M to that extent it also involves repeated distribution of moments at successive joints in frames and continues beams. However there is a major difference in distribution process of two methods. H.C.M distributes only the total joint moment at any stage of iteration. The most significant feature of Kanis method is that process of iteration is self-corrective. Any error at any stage of iterations corrected in subsequent steps consequently skipping a few steps error at any stage of iteration is corrected in subsequent consequently skipping a few steps of iterations either by over sight of by intention does not lead to error in final end moments. Advantages: It is used for side way of frames. Limitations: The rotational of columns of any storey should be functioning a single rotation value of same storey. The beams of storey should not undergo rotation when the column undergoes translation. That is the column should be parallel. Frames with intermediate hinges cannot be analyzed.

6.1.4. Approximate method: Approximate analysis of hyper static structure provides a simple means of obtaining a quick solution for preliminary design. It makes Some simplifying assumptions regarding Structural behavior so to obtain a rapid solution to complex structures. The usual process comprises reducing the given indeterminate configuration to a determine structural system by introducing adequate no of hinges. it is possible to sketch the deflected

41

profile of the structure for the given loading and hence by locate the print inflection. Since each point of inflection corresponds to the location of zero moment in the structures. The inflection points can be visualized as hinges for the purpose of analysis. The solution of structures is sundered simple once the inflection points are located. The loading cases are arising in multistoried frames namely horizontal and vertical loading. The analysis carried out separately for these two cases. Horizontal cases: The behavior of a structure subjected to horizontal forces depends upon its heights to width ratio among their factor. It is necessary it differentiate between low rise and high rise frames in this case. Low rise structures: Height < width It is characterized predominately by shear deformation. High rise buildings Height > width It is dominated by bending action

6.1.5. Matrix analysis of frames: The individual elements of frames are oriented in different directions unlike those of continues beams so their analysis is more complex .never the less the rudimentary flexibility and stiffness methods are applied to frames stiffness method is more useful because its adaptability to computer programming stiffness method is used when degree of redundancy is greater than degree of freedom. However stiffness method is used degree of freedom is greater than degree of redundancy especially for computers.

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6.2.

Seismic Analysis Procedures:

Main features of seismic method of analysis based on Indian Standard 1893(part 1): 2002 are described as follows Equivalent lateral force method: The Equivalent lateral force method is the simplest method of analysis and requires less computational effort because the forces depend on the code based fundamental period of structures with some empirical modifier. The design base shear shall first be computed as a whole, and then be distributed along the height of buildings based on simple formulae appropriate for buildings with regular distribution of mass and stiffness. The design lateral force obtained at each floor level shall be distributed to individual lateral load resisting elements depending upon floor diaphragm action. The design lateral force or design base shear and the distribution are given by some empirical formulae given in the I.S 1893. Response Spectrum analysis: This method is applicable for those structures where modes other than the fundamental one affect significantly the response of the structure. In this method the response of Multi degree of freedom system is expressed as the superposition of modal response, each modal response being determined from the spectral analysis of Singledegree of freedom system, which is then combined to compute the total response. Elastic Time history analysis: A linear analysis, time history analysis over comes all disadvantages of modal response spectrum provided nonlinear behavior is not involved. The method requires greater computational efforts for calculating the response at discrete times. One interesting advantage of this is that the relative signs of response quantities are preserved in the response histories.

6.3.

Analysis Using Staad Pro V8i:

After assigning all the properties of a structural frame only a command is used to analyze the structure and the results are obtained within seconds of time. This is the main advantage of using the software or computer aided analysis.

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6.4.

Analysis Result For Load Cases 1 To 4

For Load Case 1 (SLX)

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For Load Case 2 (SLZ)

45

For Load Case 3 (Dead Load)

46

For Load Case 4 (Live Load)

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6.5.

ANALYSIS RESULTS FOR SUPPORT REACTIONS

48

49

50

51

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**The above results are displayed from the Staad Output file. **These reaction forces and moments are evaluated for the critical load combinations 5 to 9 as shown above under load combinations. **The joints 69 to 113 show the column positions the ultimate position of reaction supports for the RC framed structure.

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CHAPTER 7 DESIGN

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INPUT TO STAAD EDITOR FOR DESIGN

55

7.1.

BEAMS

Beams are the horizontal members of the RC framed structure. Generally, beam is of two typesi) Singly Reinforced Beam and ii) Doubly Reinforced Beams. Design of beams is done as per Limit State Design of collapse (IS 456: 2000). Using Staad Pro software, the design of beam is simply done by assigning the parameters for the structure which includes the clear cover, yield strength of steel, compressive strength of concrete, maximum and minimum size of bars to be used, etc. A reinforced concrete beam should be able to resist tensile, compressive and shear stress induced in it by loads on the beam. There are three types of reinforced concrete beams 1.) Single reinforced beams 2.) Double reinforced concrete 3.) Flanged beams Beams transfer loads from slabs to columns and hence are designed for bending. Singly reinforced beams: In singly reinforced simply supported beams steel bars are placed near the bottom of the beam where they are more effective in resisting in the tensile bending stress. I cantilever beams reinforcing bars placed near the top of the beam, for the same reason as in the case of simply supported beam. Doubly reinforced concrete beams: It is reinforced under compression and tension regions. The necessity of steel of compression region arises due to two reasons; when depth of beam is restricted, the strength availability singly reinforced beam is in adequate. At a support of continuous beam where bending moment changes sign such as situation may also arise in design of a beam circular in plan.

Figure shows the bottom and top reinforcement details at three different sections. These calculations are interpreted manually. Due to the huge output of Staad Pro V8i, here we only show the design result of a beam.

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7.1.1. Design Result for Beam No. 1

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FIGURE 7. 1 Location of Beam 1 in the structure

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7.1.2. Detailing of Beam Reinforcement as per IS 13920 : 1993

FIGURE 7. 2 Beam Reinforcement

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FIGURE 7. 3

Beam Web Reinforcement

7.1.3. Check for the design of a Beam No.1:

Given data: Cross section of beam : b x d = 300mm x600 mm Vertical shear force = Vu =145.93 KN c = 0.29 N/mm2 (from able 19 of IS 456 200)

Minimum Shear Reinforcemen

: When v is less

han c , given in Table 19, minimum shear reinforcemen shall -be provided Design of Shear Reinforcemen: When v exceeds c, given in Table 19, shear reinforcemen shall be provided in any of he following forms: a) Verical sirrups, b) Ben-up bars along wih sirrups, and c) Inclined s

irrups,

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v

= =

Vu/(b x d) (As per clause 40.1 of IS 456-2000) 145.93 x 103/(550x300)

=1.216 N/mm2 v c

Design reinforcemen Vus = = = Vu- c x b x d (As per clause 40.4 of IS 456-2000) 145.93 x103 -0.29x550x300 111100 N

Shear reinforcemen shall be provided o carry a shear equal o Vu - c bd The srengh of shear reinforcemen Vus, shall be calculaed as below:

For verical sirrups: Vus = 0.87 fyAsvd/Sv (As per clause 40.4 of IS 456-2000)

Asv Sv v c b

= = = = =

oal cross-secional area of sirrup legs or ben-up bars wihin a disance Sv. spacing of

he s

irrups or ben

-up bars along

he leng

h of

he member, nominal shear sress design shear srengh of he concree, breadh of he member which for flanged beams, shall be aken as he breadh of

he web bw, fy = chrcteristic strength of the stirrup or bent-up reinforcement which shll not be

tken greter thn 415 N/mm2, = ngle between the inclined stirrup or bent- up br nd the xis of the member, not less thn 45, nd d = effective depth. 111130 N= 0.87 x 415 x 2 x x 82 x 550/Sv Sv = 140 mm

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Sv should not be more than the following 1. 0.75xd = 0.75 x 550 = 300 mm 2. 300 mm 3. Minimum shear reinforcement sacing = Sv,min

Minimum shear reinforcement: Minimum shear reinforcement in the form of stirrus shall be rovided such that: Asv/bSv 0.4/ 0.87fy (As er clause 26.5.1.6 of IS 456-2000)

Asv = total cross-sectional area of stirru legs effective in shear, Sv = stirru sacing along the length of the member, b = breadth of the beam or breadth of the web of flanged beam, and fy = characteristic strength of the stirru reinforcement in N/mm* which shall not be taken greater than 415 N/mn2 Sv=2x(/4)x82x0.87x415/(0.4x300) = Provided 2 legged 8mm @100 mm stirrus .

605 mm.

Hence matched with Staad outut.

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7.2.

COLUMNS

A column or strut is a comression member, which is used rimary to suort axial comressive loads and with a height of at least three it is least lateral dimension.

A reinforced concrete column is said to be subjected to axially loaded when line of the resultant thrust of loads suorted by column is coincident with the line of C.G 0f the column I the longitudinal direction.

Deending uon the architectural requirements and loads to be suorted, R.C columns may be cast in various shaes i.e. square, rectangle, and hexagonal, octagonal, circular. Columns of L shaed or T shaed are also sometimes used in multistoried buildings.

The longitudinal bars in columns hel to bear the load in the combination with the concrete. The longitudinal bars are held in osition by transverse reinforcement, or lateral binders.

The binders revent dislacement of longitudinal bars during concreting oeration and also check the tendency of their buckling towards under loads.

7.2.1. Positioning of columns: Some of the guiding rinciles which hel the ositioning of the columns are as follows:-

A) Columns should be referably located at or near the corners of the building and at the intersection of the wall, but for the columns on the roerty line as the following requirements some area beyond the column, the column can be shifted inside along a cross wall to rovide the required area for the footing with in the roerty line. alternatively a combined or a stra footing may be rovided. B) The sacing between the columns is governed by the lamination on sans of suorted beams, as the sanning of the column decides the san of the beam. As the san of the of the beam increases, the deth of the beam, and hence the self-weight of the beam and the total.

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7.2.2. Effective length: The effective length of the column is defined as the length between the oints of contraflexure of the buckled column. The code has given certain values of the effective length for normal usage assuming idealized and conditions shown in aendix D of IS - 456(Table 24) A column may be classified based as follows based on the tye of loading: 1) Axially loaded column 2) A column subjected to axial load and uneasily bending 3) A column subjected to axial load and biaxial bending.

Axially loaded columns: All comression members are to be designed for a minimum eccentricity of load into rincial directions. In ractice, a truly axially loaded column is rare ,if not nonexistent. Therefore, every column should be designed for a minimum eccentricity .clause 22.4 of IS code

E min

=

(L/500) + (D/300), subjected to a minimum of 200 mm.

Where L is the unsuorted length of the column (see 24.1.3 of the code for definition unsuorted length) and D is the lateral dimension of the column in the direction under the consideration.

Axial load and uniaxial bending: A member subjected to axial force and bending shall be designed on the basis of 1) The maximum comressive strength in concrete in axial comression is taken as 0.002 2) The maximum comressive strength at the highly comressed extreme fiber in concrete subjected to highly comression and when there is no tension on the section shall be 0.0035-0.75 times the strain at least comressed extreme fiber. Design charts for combined axial comression and bending are in the form of intersection diagram in which curves for Pu/fck bD verses Mu/fck bD2 are lotted for different values of /fck where is reinforcement ercentage.

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Axial load and biaxial bending: The resistance of a member subjected to axial force and biaxial bending shall be obtained on the basis of assumtions given in 38.1 and 38.2 with neutral axis so chosen as to satisfy the equilibrium of load and moment about two weeks.

Alternatively such members may be designed by the following equation: (Mux/ Muy)n +(Muy/ Muy1)n

1.) Shpe of the section 2.) Slenderness rtio (A=L+D) 3.) Type of loding, lnd 4.) Pttern of lterl reinforcement. The rtio of effective column length to lest lterl dimension is relesed to s slenderness rtio. In our structure we hve 3 types of columns. Column with bems on two sides Columns with bems on three sides Columns with bems on four sides

So we require three types of column sections. So crete three types of column sections nd ssign to the respective columns depending on the connection. But in these structure we dopted sme cross section throughout the structure with rectngulr cross section .In foundtions we generlly do not hve circulr columns if circulr column is given it mkes circle by creting mny lines to increse ccurcy. The column design is done by selecting the column nd from geometry pge ssigns the dimensions of the columns. Now nlyze the column for lods to see the rections nd totl lods on the column by seeing the lods design column by giving pproprite prmeters like 1. Minimum reinforcement, mx, br sizes, mximum nd minimum spicing. 2. Select the pproprite design code nd input design column commnd to ll the column. 3. Now run nlysis nd select ny column to collect the reinforcement detils The following figure shows the reinforcement detils of bem in std. The figure represents detils regrding 1. Trnsverse reinforcement 2. Longitudinl reinforcement The type of brs to be used, mount of steel nd loding on the column is represented in the below figure.

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Tble 7. 4 Skeleton Structure Showing Column No. 1539

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68

Figure 7.5 - Sher Bending For Column No. 1539 7.2.4. Check for Column Design: Short xilly Loded columns: Given dt

fck = 25 N/mm2 fy = 415N/mm2 puz = 19732.59 N b = 450mm d = 900mm

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Design of reinforcement Are: (As per cluse 39.6 of IS 456 2000)

Puz 19732.59

= =

0.45fckAc + 0.75fyAsc 0.45*25*(350*450-Asc) + 0.75*415*Asc

On solving the bove eqution we get Asc = 3241.15 Sq.mm.((Mtched with Output)

Design of Min(Longitudinl) reinforcement: (As per cluse 26.5.3.1 of IS 456-2000 ) 1. The cross sectionl re of longitudinl reinforcement shll not be less 0.8% , not more thn 6% of the gross cross sectionl re of the column. 2. The brs shll not be less thn 12 mm in dimeter. 3. Spcing of longitudinl brs mesured long the periphery of the column shll not exceed 300 mm. Provided min reinforcement : 32 12mm di (0.89%, 3619.95 Sq.mm.) Check for Trnsverse reinforcement : (As per cluse 26.5.3.2 of IS 456-2000 ) A) pitch : shll not be more thn the lest of the following 1) Lest lterl dimension of the compression member (350mm). 2) 16 x dimeter of longitudinl reinforcement br = 16x 12 = 192 mm 3) 300 mm B) Dimeter : 1) Shll not be less thn one fourth of the dimeter of min reinforcement. 2) Not less thn 6 mm.

Provided Tie Reinforcement: Provide 8 mm di. rectngulr ties @ 190 mm c/c.

70

7.3.

SLABS

A slb is flt two dimensionl, plnr structurl element hving thickness smll compred to its other two dimensions. It provides working flt surfce or covering shelter in buildings. It supports minly trnsverse lods nd trnsfers them to support primrily by bending ction in one or more directions. Reinforced concrete slb covers reltively lrge re compred to bem or column. Therefore volume of concrete nd hence, ded lod is lrge in the cse of slb. A smll reduction in depth of slb therefore, leds to considerble economy. But cre hs to be tken to see tht its performnce (servicebility) is not ffected due to excessive deflection nd crcking.

Clssifiction of Slb on the bsis of spnning direction: ) Spnning in one direction (One Wy Slb) One wy slb re those in which the length is more thn twice the bredth it cn be simply supported bem or continuous bem.

FIGURE 7.6

One Wy Slb (lb/l > 2)

71

FIGURE 7.7 Lod Distribution in One Wy Slb

b) Spnning in two orthogonl direction (Two Wy Slb) When slbs re supported to four sides two wys spnning ction occurs. Such s slb re simply supported on ny or continuous or ll sides the deflections nd bending moments re considerbly reduces s compred to those in one wy slb.

72

FIGURE 7.8

Two Wy Slb (lb/l > 2)

FIGURE 7.9 Lod Distribution in Two Wy Slb Checks: There is no need to check servicebility conditions, becuse design stisfying the spn for depth rtio. .) Simply supported slb b.) Continuous bem Slbs re designed for deflection. Slbs re designed bsed on yield theory This digrm shows the distribution of lods in two slbs.

FIGURE 7.10

Lod Distribution showing One wy & Two wySlbs

73

In order to design slb we hve to crete pltes by selecting the plte cursor. Now selecting the members to form slb nd use form slb button. Now give the thickness of plte s 0.125 m. Now similr to the bove designs give the prmeters bsed on code nd ssign design slb commnd nd select the pltes nd ssign commnds to it. After nlysis is crried out go to dvnced slb design pge nd collect the reinforcement detils of the slb.

FIGURE 7. 11 Monolithic connection between Slb, Bem & Column.

7.3.1. Design detil nd smple clcultion of typicl slb:6310mm

S1

3584mm

74

FIGURE 7. 12 Pln showing slbs

i.

DESIGN OF TWO WAY SLAB:Clcultion of thickness of slb using l/D = 26 Therefore, n overll depth of slb is 140 mm. Using 8mm di brs nd providing 20 mm cler cover, dxx= 140-/2-cover=140-8/2-20=116mm dyy=140-/2-cover-8=140-108mm

ii.

CALCULATION OF EFFECTIVE SPAN lx ly ly/lx = = = 3.58+dxx=3.58+.116=3.696 6.32+.133=6.456 6.456/3.696=1.76

Ded lod=DL=125.140 Live lod=LL Floor finishing (25mm thick) Plster (6mm thick) Totl lod Fctor lod = 6.75fctor of sfety Tking fctor of sfety 1.5 iv. CALCULATION FOR MOMENT

= = = = = =

3.5kN/m2 2kN/m2 0.040241=1.0 kN/m2 0.006241=0.25 kN/m2 3.5+2+1+0.25=6.75 kN/m2 6.751.5=10.125kN/m2

There will be negtive moment t continuous edge nd positive Moment t mid spn= Mx My = ==

xWulx2 yWulx2 short spn coefficient long spn coefficient

Where x Where Y v.

=

Clcultion of coefficient ccording to IS 456,cluses D-1.1 nd 24.4.1 Type of pnel = Two djcent edge continuous. x (-ve) t 1.76 = 0.084 x(+ve) t 1.76 = 0.063

vi.

Moment clcultion Mux(-ve) Mux(+ve) = = 0.08410.1253.6962= 0.06310.1253.6962= 10.90 kNm 8.175 kNm

76

Muy(+ve) Muy(-ve) vii.

= =

0.03510.1253.6962= 0.04710.1253.6962=

6.099 kNm 4.5418kNm

CHECK FOR DEPTH d= (M/Rb) R = 0.36 Xu mx/d (1-0.42Xumx/d)fck R =0.360.48(1-0.420.48)25 = 3.45 kN/mm2 b = 1000 mm M =Mx (10.90, 8.175, 6.099 4.5418 ) = 10.90 kNm dreq = (10.90106)/(3.45103100) = 72 mm

Spn Position Short t Support Long t Support

Mu (KNm) 10.90 115 115 115 115

d (mm)

Req. Ast (mm2) 274 202 111.18 150.24

Di Spcing Provided Ast (mm) #8 180 #8 240 #8 300 #8 300 279 309 168 168 (mm2)

-At Midspn 8.175 4.5418

-At Midspn 6.099

ix.

CHECK FOR DEFLECTION:Deflection=(Lx/d)Mf , For sfe, it should be less thn 26. Where, Mf is modifiction fctor.

x.

CHECK FOR SERVICEABILITY Req. pt t Shorter Midspn = Ast*100/b.d Since Req. pt < Assumed p t (0.30) = 202*100/100*115 Hence SAFE. = 0.17%

xi.

CHECK FOR SHEAR ) Long Edge Continuous : Vu,mx = 1.2 qu[Lx(e/2e+1)] Vu,mx = 1.2*10.125[3.58(1.76/2*1.76+1)] = 16.93KN Since, Ast1 = 279mm2; pt = 100*279/1000*115 = 0.24% c = from Table 19 of IS 456 = 0.35 Cl.40.2.1.1 IS 456, k=1.30 for D 16.93KN {where e = Ly/Lx}

Hence SAFE Long Edge Disconinuous: Vu,max = 0.9*(16.93/2) = 12.70KN Therefore, As

x = 202mm2 a

midspan. Assuming 50% ben

up

o resis

momen

due

o par

ial fixi

y.

78

As1 = 101mm2; c = 0.218n/mm2 k=1.3

p = 101*100/1000*115 = 0.087%

Vuc = 1.3*0.218*1000*115/1000 = 32.59 > 12.70 ; Hence OK. b) Shor Edge Coninuous: Vu,max = 1.2qu.(Lx/3) As

1 = 168mm2 Vuc = 50.85 > 14.50 ; Hence OK. = 1.2*10.125*3.58/3 = 14.50KN

Shor Edge Disconinuous: Vu,max = 0.9*(14.50/2) = 12.70KN Therefore, Asx = 168mm2 a

midspan. Assuming 50% ben

up

o resis

momen

due

o par

ial fixi

y. As

1 = 84mm2; c = 0.22n/mm2 k=1.3 Vuc = 1.3*0.22*1000*115/1000 = 32.89 > 10.875 ; Hence OK. p = 84*100/1000*115 = 0.07%

xii.

CHECK FOR DEVELOPMENT LENGTH a) 1. Long Edge Coninuous : Req.

79

For Fe415, M25;

Ld = 64.47*8 = 515.78mm Hence OK.

Ld (available) = L/4 = 3584/4 = 896mm; 2. Long Edge Disconinuous: Ld = 64.47 * 8 = 515.78mm

Assuming 50% bars ben up , M1 = 8.175/2 = 4.08KNm Vu,max = 12.70KN Lex => (Ld-1.3M1/V) = 515.78 1.3*4.08/12.70 = 98.14mm Lex => (Ld/3 bs/2) = 98.14 + 300/2

Lex = 248.14mm from inner face of suppor. Sraigh Lengh available inside inner suppor = B =bs-A B = 300-(5*8+25) = 235mm Using 90degree bend, available anchorage lengh = 8db + 235 = 64 + 235 = 299mm > 235mm Hence OK. b) 1)Shor Edge Con

inuous: Req. Ld = 64.47 * 8 = 515.78mm Available Ld = L/4 = 896mm; Hence OK

2) Shor Edge Disconinuous: Ld = 64.47 * 8 = 515.78mm Assuming 50% bars ben up , M1 = 6.099/2 = 3.049KNm Vu,max = 10.875KN

80

Lex => (Ld-1.3M1/V) = 515.78 1.3*3.049/10.875 = 151.30mm Lex => (Ld/3 bs/2) = 151.30 + 300/2

Lex = 301.30mm from inner face of suppor. Sraigh Lengh available inside inner suppor = B =bs-A B = 300-(5*8+25) = 235mm Using 90degree bend, available anchorage leng

h = 8db + 235 = 64 + 235 = 299mm > 235mm Hence OK. xiii. TORSION STEEL a) A corners near column C127 & C128, Since slab is disconinuous over boh edger, Full Torsion Seel = 0.75 Asx = 0.75*202 = 150mm2 ; will be required in boh direcion a righ angles in each of he wo meshes, One a he op and he o

her a

he bo

om up

o

he leng

h of: Lx/5 = 3584/5 = 716.8mm b) A

corner near column C126, Required area of orsion seel = 1/2(150) = 75mm2

81

7.3.2. STAAD OUTPUT for Elemen Design:

82

83

84

****************************************************************************

FIGURE 7. 13

85

7.4.

FOUNDATION

Foundaions are srucural elemens ha ransfer loads from he building or individual column

o

he ear

h .If

hese loads are

o be properly

ransmi

ed, foundaions mus be designed o preven excessive selemen or roaion, o minimize differenial selemen and o provide adequae safey agains sliding and overurning.

7.4.1. General: 1) Fooing shall be designed o susain he applied loads, momens and forces and he induced reacions and o assure ha any selemens which may occur will be as nearly uniform as possible and he safe bearing capaciy of soil is no

exceeded. 2) Thickness a

he edge of

he foo

ing: in reinforced and plain concree fooing a he edge shall be no less han 150 mm for fooing on he neiher soil nor less han 300mm above he ops of he pile for fooing on piles.

7.4.2. Bearing Capaciy of Soil: The size foundaion depends on permissible bearing capaciy of soil. The oal load per uni area under he fooing mus be less han he permissible bearing capaciy of soil o he excessive selemens.

7.4.3. Foundaion design: Foundaions are srucure elemens ha ransfer loads from building or individual column o earh his loads are o be properly ransmi

ed founda

ions mus

be designed

o preven

excessive se

lemen

are ro

a

ion

o minimize differen

ial se

lemen

s and

o provide adequa

e safe

y isola

ed fooings for muli sorey buildings. These may be square recangle are circular in plan ha he choice of ype of foundaion o be used in a given siuaion depends on a number of fac

ors. 1.) Bearing capaci

y of soil 2.) Type of s

ruc

ure 3.) Type of loads 4.) Permissible differen

ial se

lemen

s 5.) Economy

86

A fooing is he boom mos par of he srucure and las member o ransfer he load. In order

o design foo

ings we used

he sof

ware named STAAD FOUNDATION V8i. These are he ypes of foundaions he sofware can deal. Shallow (DB) Pile Cap Driller Pier

7.4.4. Crierion for Combined Srip Fooing: Heavily loaded column when hese are suppored on relaively weak or uneven soils having low bearing capaciy (which is equal

o 175KN/m2) need large bearing area. In such case, Con

inuous S

rip Fooing is provided o suppor more han wo columns in a row, insead of individual fooing. Thus he coninuous srip fooing runs along he column row. The srip fooings have T secion and he flange of T secion faces downwards. The projec

ion of T-sec

ion behaves as a Can

ilever. The

hickness of

he flange is kep consan, when he canilever projecion is of small lengh. Oherwise, he deph of flange is increased owards he rib. The weigh of he fooing is no considered in srucural design because i is assumed o be carried by he subsoil. I

is similar

o a floor res

ing on a sys

em on a sys

em of beams and columns. 7.4.5. Design using STAAD FOUNDATION V8i:

87

-Impor he Saad Pro V8i analyzed file ino Saad Foundaion V8i using he IMPORT opion.

Figure 7. 14 S

aad Founda

ion Page Showing Con

inuous S

rip Foo

ing When

he file is impored from he Saad Pro V8i, here is no need o specify he column posiions, as i is already specified in he Saad Pro file. The main advanage of his sofware is ha i auomaically generaed he reacion and momen values a

suppor

s when

he load cases are defined.

FIGURE 7. 15 Zoom View of coninuous srip Foundaion & Columns

88

-The load combinaion or he load cases are generaed (seleced) for which he foundaion is o be designed. Assign Loading: - 1.5(DL + LL)

-

The nex sep is o creae he job for he fooing (i.e. Combined Fooing.) Now he design parameers are enered which includes: Concree & Rebar, Cover & Soil, Foo

ing Geome

ry

FIGURE 7. 16 Concree & Rebar Parameers

FIGURE 7. 17 Cover & Soil Parame

ers

89

FIGURE 7. 18 Fooing Dimensions

The following inpu daa is required regarding maerials, Soil ype, Type of foundaion, safey facors. Type of foundaion: Combined. Uni weigh of concree: Minimum bar spacing: Maximum bar spacing: Srengh of concree: Yield srengh of seel: Minimum bar size: Maximum bar size: Bo

om clear cover: Uni

weigh

of soil: Soil bearing capaciy: Minimum lengh: 25KN/m^3 50mm 500mm 35N/mm^2 415 n/mm^2 12mm 60mm 50mm 22 KN/m^3 175 KN/m^3 1000mm

90

Minimum widh: Minimum hickness: Maximum lengh: Maximum widh: Maximum hickness: Plan dimension: Aspec

ra

io:

3500mm 500mm 70000mm 40000mm 2000mm 50mm 1

Safe

y agains

fric

ion, 0.5; over

urning, 1.5; sliding,1.5 Now

he las

s

ep is o click on DESIGN. Afer he analysis, deailed calculaion of each and every fooing is given wih plan and elevaion. Table 7.1Fooing No. Lef Overhang (m) 1 2 3 4 5 3.875 4.975 2.775 6.475 8.225

Dimensions of he Coninuous Srip FooingsRigh Overhang (m) 3.875 4.975 2.775 6.475 8.225 Lengh (m) 23.040 62.790 20.840 65.760 55.210 Widh (m) 9.25 11.450 7.050 14.450 17.950 Thickness (m) 0.700 1.100 0.700 1.300 1.250

91

Table 7.2. Fooing No. Main Seel Top 1 2 3 4 5 #12 @ 125mm c/c #12 @ 75mm c/c #12 @ 125mm c/c #12 @ 50mm c/c #12 @ 50mm c/c

DESIGN RESULTS Fooing Reinforcemen Main Seel Boom Secondary Seel Top #12 @ 125mm c/c #12 @ 75mm c/c #12 @ 125mm c/c #12 @ 50mm c/c #12 @ 75mm c/c Secondary S

eel Bo

om #16 @50mm c/c #16 @50mm c/c #12 @50mm c/c #20 @75mm c/c #25 @50mm c/c

#32 @ 75mm c/c #40 @75mm c/c #20 @50mm c/c #40 @50mm c/c #40 @50mm c/c

7.4.6.

Design Calculaions for Combined Fooing 1 (FC1)

Column Dimensions for Column No. 69, 103, 102 and 101 (Combined Fooing No. FC1) Column Shape: Column Lengh - X (Pl): Column Widh - Z (Pw): Recangular 1000mm 500mm

Lengh of lef overhang : Lengh of righ overhang : Is he lengh of lef overhang fixed? Is he lengh of righ overhang fixed? Minimum widh of fooing (Wb) : Minimum Thickness of fooing (Do) : Maximum Widh of Fooing (Wb) : Maximum Thickness of Foo

ing (Do) :

1.00 m 1.00 m No No 3.50 m 500.00 mm 40000.00 mm 2000.00 mm

92

Maximum Lengh of Fooing (Lo) : Lengh Incremen : Deph Incremen :

70000.00 mm 50.00 mm 50.00 mm

Cover and Soil Properies Pedesal Clear Cover : Fooing Clear Cover : Uni Weigh

of soil : Soil Bearing Capaci

y : Soil Surcharge : Dep

h of Soil above Foo

ing : Deph of Waer Table : 50.00 mm 50.00 mm 22.00 kN/m3 175.00 kN/m2 44.00 kN/m2 2.00 m -4000mm

Concre

e and Rebar Proper

ies Uni

Weigh

of Concre

e Compressive S

reng

h of Concree : Yield Srengh of Seel : Minimum Bar Size : Maximum Bar Size : Minimum Bar Spacing : Maximum Bar Spacing : 25.000 kN/m3 35.000 N/mm2 415.000 N/mm2 12 60 50.00 mm 400.00 mm

Design Calculaions

93

Fooing Size Calculaions Reducion of force due o buoyancy = Minimum area required from bearing pressure, Amin = Pcri

ical / qmax : Area from ini

ial leng

h and widh, Ao = L x W: Therefore, Final fooing dimensions are: Lengh of fooing, L : Widh of fooing, W : Deph of fooing, Do : Area, A : Lengh of lef overhang, Llef_overhang : Lengh of righ overhang, Lrigh_overhang : Table 7.3. 23.04 9.25 0.70 213.12 3.88 3.88 m m m sq m m m -0.00 kN

123.46 sq m 60.51 sq m

94

Table 7.4.

If Au is zero, here is no uplif and no pressure adjusmen is necessary. Oherwise, o accoun for uplif, areas of negaive pressure will be se o zero and he pressure will be redisribued o remaining corners.

Table 7.5.

Design for Flexure Sagging momen along lengh Effecive Deph = Governing momen

(Mu) As Per IS 456 2000 ANNEX G G-1.1C Limi

ing Fac

or1 (Kumax) = Limi

ing Facor2 (Rumax) = Limi Momen Of Resisance (Mumax)= = 0.479107 = 4822.007604 kN/m^2 = 7928.346683 kNm = 0.63 m

=17882.520713 kNm

95

Mu

Mu

Sh