EQ Highrise3

7/21/2019 EQ Highrise3

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High Rise Buildings in Earthquakes


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Viscous Fluid dampers

Suspension system: a mechanical system ofsprings and shock absorbers that connect the

wheels and axles to the chassis of a wheeled

vehicle


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Viscous fluid dampers

similar to shock absorbers in automobiles

Oil suspension

Gas suspension

3


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The Function of suspension system:

The job of a car suspension are:

- to carry the static weight of the vehicle

- to maximize the friction between the tires

and the road surface,- to provide steering stability with good

handling (minimize body roll)

- to ensure the comfort of the passengers

(ability to smooth out a bumpy road).


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Viscous fluid dampers

installed as part of a building's bracingsystem using singlediagonals.sways to and fro, the piston is forced in and out of thecylinder.

5


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Active Control

Control system to keep stresses / strains /displ. / accel. (outputs) at certain locationsbelow specified bounds (peak, rms) when

disturbances(wind, earthquake) belowspecified boundare applied.

Designer decides choice of on comfort (accelerations)

safety (stresses).


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Tuned Mass Damper (TMD)


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Active control

First full scale application of active control to abuilding was done on Kyobashi Seiwa building(Japan) in

Two AMDs were used.

4t - transverse motion

1t - torsional motion.

Can also use Magnetorheological fluid dampers(semi-active), active tendons, etc


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Active Control


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Active control with TMD


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Active control with TMD


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Orifice based Semi-Active

Suspension


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Orifice based Semi-Active

Suspension


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MR fluid based Semi-Active

Suspension


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MR Fluid

- oil and varying percentages of ferrous particles

(20-50 microns in diameter) that have been

coated with an anti-coagulant material.

- Varying the magnetic field strength

variation inviscosit


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Active VS Semi-Active

Semi-Active:

Lower implementation cost

Lower power consumption

Easier to control

Simpler design

Easy to install

Disadvantage: damper constraint, the force range islimited, performance is not as good as activesystem


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Active System: Wider range of force

No force-velocity constraint

Can achieve better performance (vehicle dynamics)

Disadvantages: power consumption is high, higher

weight to power ratio, expensive, major modification

should be made before installing active system intothe existing vehicle


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Semi-Active: Lower implementation cost

Lower power consumption

Easier to control

Simpler design

Easy to install

Disadvantage: damper constraint, the force range is

limited, performance is not as good as active

system


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Non Structural IssuesGood connections of non-structural

building contents with building


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SPACE FRAME


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Joist used for floor support


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Joist Girder

Joist Seat


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Joist Bridging


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Steel Trusses

Heavier Members

Can Carry Larger Loads &

Span Greater Distances

Typically Specially Fabricated

Truss to Span a

Hotel Atrium

Heav Trusses for the Seattle Stadium


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Cold Formed Steel

Formed by rolling or bending sheet steel

Light Steel Framing; C-Shaped - Most Common;

Frequently used for partition & exterior wall

framing

Metal Decking


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Open Web Steel Joists

Mass produced steel trusses

Common Uses

Floor Support Roof Support

Joist spacing depends

Load Span capability of deck

Typically 2 to 10 feet


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DEFINITION:

A three-dimensional structures.

The assembled linear elements are arranged

to transfer the load.

Take a form of a flat surface or curve surface.

Designed with no intermediate columns to

create large open area.


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EXAMPLES OF BUILDING


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SAN SIRO STADIUM, MILAN


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STANSTED AIRPORT, LONDON


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Joist used for floor support


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Open Web Steel Joists

Mass produced steel trusses

Common Uses

Floor Support Roof Support

Joist Spacing Depends on;

Load Span capability of deck

Typically 2 to 10 feet

Spans; K-series (up to 60), LH(Longspan) to 96, DLH(Deep Longspan) to 144


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Joist Girder

Joist Seat


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Joist Bridging


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Steel Trusses

Heavier Members

Can Carry Larger Loads &

Span Greater Distances

Typically Specially Fabricated

Truss to Span a

Hotel Atrium

Heav Trusses for the Seattle Stadium


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Cold Formed Steel

Formed by rolling or bending sheet steel

Light Steel Framing; C-Shaped - Most Common;

Frequently used for partition & exterior wall

framing

Metal Decking


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Load Distribution


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TYPES OF SPACE FRAME

Two and three-way grids

Characterized as two way or three way

Single, Double and Triple Layered

Single layer frame has to be singly or doubly

curved.

double layered and flat.

Triple layered span building.


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COMPONENTS

Consists of axial members

linear members

connectors


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Basic elements

Planar latticed

Pyramid with square base Part of octahedron

Pyramid with triangular base Part of tetrahedron


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CONNECTORSTuball Node/Mero Connector

A hollow sphere

Circular hollow section

member fitted at its ends by

welding.

Connection from inside the

cup is using bolt and nut.


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Mero Connector

Dia ranging from

46.5mm to

350mm

Up to 18

members


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Cruciform gusset plate


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Bearing joint

Nodus Connector

Rectangular / circular

hollow sections

Chord connectors welded

to hollow members


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3) T i d ti C t


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3) Triodetic Connector

It consists of a hub, usually an aluminium

extrusion, that has slots or key ways, which the

ends of members are pressed or coined to

match the slots.


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4) Hemispherical Dome Connector

Usually use for double layer domes.

Structural span more than 40m.

More economical for long span.

The jointing is connect by sliting the end of the

tube or rod with the joint fin. There are 2 types of joint, pentagonal joint and

hexagonal joint.


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Fishplate Connectors


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Support

Perimeter support

Multi column

Perimeter and column


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ADVANTAGES Light

Elegant & Economical

Carry load by three dimensional action

High Inherent Stiffness

Easy to construct Save Construction Time & Cost

Services (such as lighting and air conditioning)

can be integrated with space frames

Offer the architect unrestricted freedom in

locating supports and planning the subdivision

of the covered space.


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Construction Metods

Assembly in air

Erecting in strips or blocks

Assembly by sliding elements in air

Hoisting by derrick crane or tower cranes

Lifting up whole frame

Jacking up


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Failure

Member buckling

Local or dimple bucking

General buckling

EQ Highrise3

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