SEISMIC VULNERABILITY ASSESSMENT OF IRREGULAR

REINFORCED CONCRETE BUILDINGS IN AUSTRALIA

© BUSHFIRE AND NATURAL HAZARDS CRC 2017

Alireza Mehdipanah1,2, Elisa Lumantarna1,2, Nelson Lam1,21 Department of Infrastructure Engineering, The University of Melbourne, Parkville 3010, VIC2 Bushfire and Natural Hazards Cooperative Research Centre, Melbourne Australia

SEISMIC DESIGN AND ASSESSMENT OF IRREGULAR REINFORCED CONCRETE BUILDINGS IN THEREGIONS OF LOW TO MODERATE SEISMICITY SUCH AS AUSTRALIA IS INVESTIGATED THISPOSTER.1. INTRODUCTION

Reinforced concrete buildings constitutea significant proportion of constructionsin Australia. Many existing buildings inAustralia and other low to moderateseismic regions have been designed withlittle to no consideration of ductiledetailing. The majority of these buildingsalso possess irregularities which canexacerbate their vulnerability in anearthquake.

2. STUDIES BASED ON LINEAR RESPONSE

Seismic response of 75 buildings withvarious locations and extent ofirregularities in elevation was evaluated.

2.1 Irregular buildings behaviour

Comparison between the seismicresponse of vertical regular and verticalirregular buildings have shown thatdiscontinuities in columns within thebuilding do not result in soft-storeymechanism.

2.2 Generalised lateral force method(GLFM) of analysis

Seismic design codes of practice requirethe use of dynamic analyses for irregularbuildings. However, dynamic analysescan be computationally expensive andrequire expert judgment, especially asfar as three-dimensionally modelling isinvolved.

A building to be assessed

Periods of the modes of vibration of buildings

2.3 GLFM for torsionally balanced (TB)buildings

Using the suggested generalised modeshapes, a simple method weredeveloped to estimate thedisplacement profile of taller buildings.

2.3 GLFM for torsionally Unbalanced (TU)buildings

The simplified method has been extendedto account for the effects of torsion dueto plan asymmetry.

∑∑∑∑

a

Comparison of the displacement profiles

based on the proposed GLFM and

dynamic method

Comparison of the displacement

profiles based on the proposed and dynamic method

Generic mode

shapes of first and second modes

1Ω 1 0

0 100

3. STUDIES BASED ON NONLINEARRESPONSE

Ductility and failure behaviour ofmulti-storey buildings featuringdiscontinuities is investigated.

3.1. Component modelling

A systematic analytical modellingtechnique for the simulation oflimited-ductile beam-columnelements is proposed.

3.2. Building modelling

Using the proposed technique,OpenSEES finite element packageemployed to build 3D case studymodels.

3.3. Observed mechanisms

Shear failure in the transfer beamoccurs prior to the point that structurereaches the calculated targetdisplacement for some cases.