safety vulnerability buildings in earthquake...

Architectural Considerations(GEM launch in the Caribbean)

04 May 2011

Tony Gibbs 1

Architectureand the Safety and Vulnerability of Buildings

in Earthquake Zonesq

Chairman – Tony Gibbs

Panellists:Robert Woodstock, Gary Turton, Jenifer Smith


04 May 2011

Tony Gibbs 2

Buildings are designed by architects and engineers. In reality, in most cases, buildings principally for human y, , g p p yoccupancy are designed conceptually by architects. That is to say that architects are the ones principally responsible for the configuration of buildings for human occupancy.


04 May 2011

Tony Gibbs 3

C ldC Arnold


04 May 2011

Tony Gibbs 4

Configuration has to do with the shape and size of the b ildi I it bl h d i t l t tbuilding. Inevitably shape and size to a large extent determines (or greatly influences) the type, shape, arrangement size location and most other aspects ofarrangement, size, location and most other aspects of the structural concept.


04 May 2011

Tony Gibbs 5

C Arnold


04 May 2011

Tony Gibbs 6

In the words of Geoffrey Wood (one of the five f di t f O A & P t )founding partners of Ove Arup & Partners):

“Earthquake‐resistant design is really a problem forEarthquake resistant design is really a problem for architects."


04 May 2011

Tony Gibbs 7

Either the architect has a better‐than‐usual knowledge of the basic principles of the conceptual design of earthquake resisting systems

or

The architect should involve the structural engineer in the initial discussions and development of the building concept.


04 May 2011

Tony Gibbs 8

Tony Gibbs


04 May 2011

Tony Gibbs 9

The Tri‐services Manual of the USA Army, Navy and Air Force states:Force states:

"A great deal of a building's inherent resistance g f gto lateral forces is determined by its basic plan layout. . . .

"Engineers are learning that a building's shape, symmetry and its general layout developed in the conceptual stage are more important than the accurateconceptual stage are more important than the accurate determination of the code‐prescribed forces. . . ."


04 May 2011

Tony Gibbs 10

Irregularities in the floor planIrregularities in the floor planIrregularities in the floor plan

10


04 May 2011

Tony Gibbs 11

Structural engineer William Holmes, writing in 1976, states:

"It has long been acknowledged that the configuration and the simplicity and directness of theconfiguration, and the simplicity and directness of the seismic resistance system of a structure, is just as important as the actual lateral design forces."


04 May 2011

Tony Gibbs 12

Examples of structures withirregularities in elevation

Examples of structures withirregularities in elevation

Examples of structureswith irregularities in elevation

12


04 May 2011

Tony Gibbs 13

Discontinuity in the elementsand the flow of forcesDiscontinuity in the elementsand the flow of forces


04 May 2011

Tony Gibbs 14

Henry Degenkolb is emphatic in stressing the importance of configuration:

"If we have a poor configuration to start with, all th i d i t i b i llthe engineer can do is to improve a basically poor solution as best he can. Conversely, if we start off with a good configuration and a reasonable framinga good configuration and a reasonable framing scheme, even a poor engineer can't harm its ultimate performance too much.

"This last statement is only slightly exaggerated.”


04 May 2011

Tony Gibbs 15

Those quotations above warrant discussion among the various disciplines involved in the design and building processes. Terán (Nicaraguan architect) recommends th t b ildi b " i l ti t i lthat buildings be "simple, continuous, symmetrical, straightforward, and repetitive". This advice is given not as an absolute but as a qualitative factor thatnot as an absolute, but as a qualitative factor that influences the reliability of the structure. Terán asks for understanding and knowledge among the disciplines, not the imposition of mandatory constraints.


04 May 2011

Tony Gibbs 16

Use of seismic joints for structural designs of buildings with complex floor plans



16


04 May 2011

Tony Gibbs 17

Asymmetry (false symmetry) due to the location of structural elements

Asymmetry (false symmetry) due to the location of structural elements

Asymmetry (false symmetry)due to the location of rigid elements

17


04 May 2011

Tony Gibbs 18


04 May 2011

Tony Gibbs 19

Irregular elevationsIrregular elevationsIrregularities in elevation

19


04 May 2011

Tony Gibbs 20

Soft storiesSoft stories


04 May 2011

Tony Gibbs 21

Damage caused by shearing forceon ground-floor columnsDamage caused by shearing forceon ground-floor columns

PAHO


04 May 2011

Tony Gibbs 22


04 May 2011

Tony Gibbs 23

Structural damage mechanismsStructural damage mechanismsStructural damage mechanisms

23


04 May 2011

Tony Gibbs 24

Interaction between structural and nonstructural elements

Interaction between structural and nonstructural elements

Interaction betweenstructural and nonstructural elements

24


04 May 2011

Tony Gibbs 25

Nonstructural ComponentsNonstructural ComponentsNonstructural Components

25


04 May 2011

Tony Gibbs 26

Response of different components and contents of a building during an earthquake



T. Guevara, 1999

26


04 May 2011

Tony Gibbs 27

Architectural componentsthat run across

Architectural componentsthat run across

SeismicJointSeismicJoint

that run across seismic joints must be

that run across seismic joints must bemust becorrectly detailedmust becorrectly detailed


04 May 2011

Tony Gibbs 28

Basic servicesmay be interrupted d t f il

Basic servicesmay be interrupted d t f ildue to failures associated with the inappropriate crossing

due to failures associated with the inappropriate crossinginappropriate crossing of seismic jointsinappropriate crossing of seismic joints


04 May 2011

Tony Gibbs 29

Performance Basis1997 BSSC NEHRP Provisions

Building P f

Frequent

Performance

Frequent

Motion Ordinary Buildings

Emergency Response

Design

roun

d M High Occupancy

Maximum Considered

Gr

FEMA


04 May 2011

Tony Gibbs 30

EdificioConvenzionale

Edificio conIsolamento alla base

Fc2 >> Fc1

Ac >> AiFc >> FiDc >> DiSc >> Si Fi2 Fi1

BRITE EURAM Project, 1993Base isolated building

Conventional building

Ac Ai

Fc2Fi2

ndro

Mar

telli

ndro

Mar

telli

Dc DiFc1 Fi1

urce

: Ale

ssan

urce

: Ale

ssan

SiScSo

uSo

u

A Z I O N E S I S M I C A

H i t lH i t lHorizontal seismic action

HorizontalHorizontalseismic isolationseismic isolationseismic isolationseismic isolation(case of High Damping Rubber Bearings (case of High Damping Rubber Bearings –– HDRB)HDRB)


04 May 2011

Tony Gibbs 31

Base-isolation technique

with

with C

entehout B

h Base

er of Informat

Base-is

e-isola

ion on Naturasolatio

ation

l Disaster R

eseon earch


04 May 2011

Tony Gibbs 32

EdificioConvenzionale

Edificio condissipatori Energetici

Fc2 >> Fc1

Ac > AeFc > FeDc > DeSc > Se Fe2 > Fe1

EEAc AeFc2 Fe2

EnergyEnergydissipationdissipation

Dc DeFc1 Fe1

dissipationdissipation

Sc Se Tests with electroinductive dampers on the ENEA shake table.

A Z I O N E S I S M I C A

Source: Alessandro MartelliSource: Alessandro Martelli


04 May 2011

Tony Gibbs 33

Elastic-plastic d

SMAload

limiting dampers

gdevices

Visco elastic

Viscous dampers

Visco-elastic dampers

Shock transmitterSource: Alessandro MartelliSource: Alessandro Martelli


04 May 2011

Tony Gibbs 34

Method of “strengthening”:dissipation of energy used in the central offices of

Instituto Mexicano del Seguro Social-México (PAHO)Instituto Mexicano del Seguro Social-México (PAHO)


04 May 2011

Tony Gibbs 35

The panel will examine the problems for theThe panel will examine the problems for the architectural designer when confronted by the earthquake hazard and some of the possible solutions q pto those problems.

It is also hoped that the GEM regional programme would have a measurably positive influence on reducing the vulnerability of future buildingsreducing the vulnerability of future buildings.

safety vulnerability buildings in earthquake...

Documents