structural design and computer modelling...bar elements model in software idea statica types of...

STRUCTURAL DESIGN AND

COMPUTER MODELLING

Ing. Jan Koláček, Ph.D.

Basic structural members

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Basic structural members

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Type of structures

Air view of district Brno-Kohoutovice

• Building structures

• Engineering structures

• Bridges

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Type of structures



• Bridges

Oil tanks in Loukov 5

Type of structures



• Bridges

Willamette river Bridge in Oregon, USA 6

1. Building structures

• housing

• commercial

• administrative

• manufactural

• agricultural

• stocking, etc.

distinguished according to their purpose:

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1. Building structures are formed:

• by load bearing structures – transform actions imposed on the structures

• by non-load bearing structures – additional function

Load bearing structures:

• vertical members – walls, columns, piers

• horizontal members – roofs, ceilings

• other members – stairs, arches

• hall structures

• multi-storey buildings

Building structures:

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1. Building structures Hall structures

• mostly of one storey (possibly in-built storey)

• used as manufactural, storing, sports, exhibitory, etc.

• one or multi tracts, purlin/non-purlin system

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1. Building structures Hall structure – non-purlin system

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1. Building structures Multi-storey buildings

Structural systems:

• wall

• skeleton

• combined

• special

According to the orientation of vertical structures they are divided into:

• longitudinal

• transversal

• two-ways

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1. Building structures Multi-storey buildings – wall systems

• principal member is a wall

• masonry, precast or cast in-situ concrete

• span of tracts is mostly 3-6 m (restrain disposition)

• transversal system (suitable for housing), longitudinal system

(administrative buildings)

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1. Building structures Multi-storey buildings – skeleton system

• developed from wall system

• principal members are pier or column (reduction of walls)

• due to wind effect have to be supplied by shear walls or cores

• skeleton system has lower stiffness compared to wall system

• better variability of arrangement

Basic division of skeleton system:

• framed

• non-framed

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1. Building structures Multi-storey buildings – skeleton system - framed

• columns are jointed with horizontal beams supporting floor slab

• recommended material is cast in-situ, precast or prestressed

concrete

• cross frames resist well to the wind (higher stiffness) – for high-rise

buildings

• longitudinal frames – for common buildings only

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1. Building structures Multi-storey buildings – skeleton system – non framed

• slab with column head

• flat slab

• combined

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1. Building structures Multi-storey buildings – skeleton system – non framed

Column heads skeleton system

• better safety against punching

• shorter span of slabs

• with high load bearing capacity – manufacturing and storing

halls

Flat slab skeleton system

• shall be more reinforced around columns (punching)

• flat ceiling

• suitable for common houses

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1. Building structures Multi-storey buildings – combined

• combination of wall and skeleton systems

• many variants – longitudinal wall system combined with skeleton

system, two-ways skeleton system with core, etc.

• suitable for high-rise buildings (skyscraper), undermined areas and

seismic active area

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2. Engineering structures

• underground

• water

• technological

• towers, masts and chimneys

• special

Special structures (difficult static and structural solution):

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• foundation structures

• various underground structures

Underground structures

• shallow foundation – spread footings, combined footings and mat

foundations

Foundation structures are:

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• deep foundation – piles, micropiles, wells and caissons

Foundation structures are:

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• for transport (railway, traffic, pedestrian, etc.)

• for water service (water supplies, etc.)

• for energetic (telecommunication, cables, collector, etc.)

• halls (hydroelectric power station, gas reservoirs, water tank,

sewerage plants, etc.)

Various underground structures are used:




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• dams

• weirs

• lock chambers

• hydro power stations

• pumped-storage hydro power station

Water structures

• dominant material is plain concrete, reinforced concrete and steel

For example :

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• blast furnace

• coking plants

• petroleum refinery

• cooling towers

Technological structures

For example:

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• fixed supported freestanding

towers

• transmission masts

• etc.

Towers, masts and chimneys

For example

• tall slim structures

• suitable material is steel (towers, masts) or concrete (chimneys)

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2. Engineering structures Special structures

• tanks

• reservoirs

• silos

• pools

• etc.

Oil tanks in Loukov 25

3. Bridges Bridge structures

• are structures built to span physical obstacles (such as a body

water, valley or road)

They can divided into three types:

• bridges (clear span greater than 2,0 m)

• culverts (clear span less than 2,0 m)

• pedestrian bridges (serve pedestrians or bicyclists)

Bridge across the Swiss Bay of Vranov Lake 26

3. Bridges Bridge components:

• superstructure

• substructure

• foundation

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3. Bridges Substructure

• abutments – (external support) a wall supporting the ends of

a bridge including footing, etc.

• piers – (internal support) columns, pier shaft, web wall, etc.

• wingwalls

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3. Bridges Substructure

• abutments – (external support) a wall supporting the ends of a

bridge including footing, etc.

• piers – (internal support) columns, pier shaft, web wall, etc.

• wingwalls

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3. Bridges Superstructure

• a part of bridges which transfer the action (reaction) of loads to

substructure

Bridge deck

• a part of superstructure which is on the top of a bridge

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Main structure

• is supporting system of the bridge

3. Bridges Type of superstructure (span type):

• slab

• beam

• arch

• vault

• cable-stayed

• suspension

• rigid frame

• etc.

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• slab

• beam

• arch

• vault

• cable-stayed

• suspension

• rigid frame

• etc.

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• slab

• beam

• arch

• vault

• cable-stayed

• suspension

• rigid frame

• etc.

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• slab

• beam

• arch

• vault

• cable-stayed

• suspension

• rigid frame

• etc.

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3. Bridges

Pylon

Stays Type of superstructure (span type):

• slab

• beam

• arch

• vault

• cable-stayed

• suspension

• rigid frame

• etc.

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3. Bridges

Bridge deck

Type of superstructure (span type):

• slab

• beam

• arch

• vault

• cable-stayed

• suspension

• rigid frame

• etc.

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3. Bridges Next classification of bridges

• railroad (railway, tram, funicular, etc.)

• vehicular (road, highway, etc.)

• pedestrian

• material handling

• migration (migration of animal)

function:

• masonry

• concrete

• steel

• timber

• composite

structure materials:

• others

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Design process:

• definition of geometry of the structure,

• definition of the connecting joints (mutual connection of individual

members),

• design of material characteristics,

• design of cross sections of individual members,

• determination of loads and load combinations,

• calculation (computing) of the structure,

• dimensioning of members and connecting joints,

• design (construction drawings) of the structure,

• production of members and blocks of the structure,

• assembly of the structure,

• construction drawings of the structure as built

Calculation models of structures

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can be defined as a model that simulates the behaviour of the real

structure.

Special notice shall be taken to the following definitions:

• geometry

• method of supporting

• materials of used members

• dimensioning of members

• action of loads

Based on this model it is

possible to perform analysis.

Calculation models of structures

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Four fundamental type of elements are used

• bar elements

• surface element

• brick elements

Bar elements

• are idealized by its centre line

• suitable for columns, arches, ties and beams

• the span is not less than 3 times the overall section depth and

width.

• according to behaviour in the structure as follows:

• truss – compressive and tensile normal

forces are dominantly

• beam – is loaded dominantly by the

loads which act predominantly

perpendicular to the centre line

Bar elements model in software IDEA StatiCa

Types of elements

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Walls

• are loaded dominantly in the centre line

• usually serve as bracing members of multi-story

buildings

• section depth exceed 4x its width and the height

is more than 3x the overall section depth Slabs

• are loaded dominantly perpendicular to the

central plane

• minimum dimension is not less than 5x the

overall slab thickness

• act as one-way, two-way of flat slabs (supported

locally by columns)

Types of elements Surface elements – are idealized by their central surface that

are either flat (plates) or curved (shells). Plate elements are

slabs and walls.

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Shells

• are thin-walled spatial structure supported at all edges

• loaded mostly by uniform load acting in the direction

approximately perpendicular to the surface

• we distinguish simple curvature and double curvature

Types of elements Surface elements – are idealized by their central surface that

are either flat (plates) or curved (shells). Plate elements are

slabs and walls.

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Brick elements

• in cases where there are dimensions of the elements of all

direction comparable

• difficult computing

Types of elements

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Elements are usually supported as following:

• roller - are free to rotate and translate along the surface upon

which the roller rest,

• pinned - can resist both vertical and horizontal forces but not a

moment - they will allow the structural member to rotate, but not

to translate in any direction,

• fixed - can resist vertical and horizontal forces as well as a

moment - they restrain both rotation and translation.

Production of calculation models

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Elements are usually connected with each other. We distinguish

• pin connections - has allowed rotation around a distinct axis,

and prevented translation in two direction

• fixed connections - due to the fact that can resist vertical and

lateral loads as well as develop a resistance to moment

• combined connections

Pin and fixed connections are very common


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Examples of connection checking by method

CBFEM


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• calculation models made from beam elements

are used for steel and timber structures

• in addition to beam elements surface elements

(slabs, walls and shells) are used for concrete

structures

• brick elements are suitable for detailed

calculation models


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• exact manual solution – usage at basic tasks

• numerical computer calculation – in practise only this is used –

enables interconnection with drawings, assessments, etc.

Numerical calculations - in building practice they are based on the

finite element method (FEM).

Solution and computing

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Willamette river bridge in Oregon, USA

Examples of FEM models

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Model test of cable supported bridge


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51 Oil tanks in Loukov


52 Construction work on the pedestrian bridge in Kroměříž


53 Pedestrian bridge over the Elbe river in Hradec Králové - competition


54 Tower for strap testing, Dolní Loučky

2008 Summer Olympic games - The Beijing National Stadium (The bird‘s nest)


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Burj Khalifa -Scyscraper in Dubai


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References

• Procházka, J., Štemberk, P.: Concrete structures 1, Nakladatelství

ČVUT, Praha, 2007

• Procházka, J., Štemberk, P.: Design procedures for reinforced

concrete structures, Nakladatelství ČVUT, Praha, 2009

• Gartner, O., Kuda, R., Procházka, M.: Betonové konstrukce VI –

Zásady pro navrhování betonových konstrukcí, VUT Brno, Brno,

1985.

• Bajer, M., Pilgr, M., Veselka, M.: Konstrukce a dopravní stavby,

Moduly BO01-MO1, Studíjní opory VUT v Brně

• Karmazínová, M., Sýkora, K., Šmak, M.: Konstrukce a dopravní

stavby, Moduly BO01-MO2, Studíjní opory VUT v Brně

• Nečas, R., Koláček, J., Panáček, J.: BL12 - Betonové mosty I –

zásady navrhování, VUT v Brně, Brno, 2014

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WE BUILT TOO MANY WALLS

AND NOT ENOUGH BRIDGES. ISAAC NEWTON

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structural design and computer modelling...bar elements model in software idea statica types of...

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