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

• Building structures

• Engineering structures

• Bridges

Oil tanks in Loukov 5

Type of structures

• Building structures

• Engineering 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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2. Engineering structures

• foundation structures

• various underground structures

Underground structures

• shallow foundation – spread footings, combined footings and mat

foundations

Foundation structures are:

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2. Engineering structures

• foundation structures

• various underground structures

Underground structures

• deep foundation – piles, micropiles, wells and caissons

Foundation structures are:

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2. Engineering structures

• 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:

• foundation structures

• various underground structures

Underground structures

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2. Engineering structures

• 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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2. Engineering structures

• blast furnace

• coking plants

• petroleum refinery

• cooling towers

Technological structures

For example:

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2. Engineering structures

• 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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3. Bridges Type of superstructure (span type):

• slab

• beam

• arch

• vault

• cable-stayed

• suspension

• rigid frame

• etc.

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3. Bridges Type of superstructure (span type):

• slab

• beam

• arch

• vault

• cable-stayed

• suspension

• rigid frame

• etc.

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3. Bridges Type of superstructure (span type):

• 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

Production of calculation models

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Examples of connection checking by method

CBFEM

Production of calculation models

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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

Production of 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

Examples of FEM models

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Examples of FEM models

51 Oil tanks in Loukov

Examples of FEM models

52 Construction work on the pedestrian bridge in Kroměříž

Examples of FEM models

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

Examples of FEM models

54 Tower for strap testing, Dolní Loučky

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

Examples of FEM models

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Burj Khalifa -Scyscraper in Dubai

Examples of FEM models

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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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