25-08-2017, 09:32 PM
Proposed Rapid Visual Screening Procedure for Seismic Evaluation of RC Frame Buildings in India
Abstract
Severe damage and poor performance of RC buildings in India during earthquakes are a matter
of serious concern. There is a need to develop suitable screening methods for seismic safety of
existing buildings so that prioritization may be undertaken on the deficient buildings. RVS
methodologies developed in other countries (eg, FEMA, 2002 in the US and METU, 2003 in
Turkey) are not appropriate for application in Indian conditions. Systematic studies on
calibration of damage data of the 2001 Bhuj earthquake in India has been carried out for the first
time in India. An expression has been developed for assigning Performance Scores to buildings
based on presence or absence of some very general, broad based and easily observable
vulnerability parameters that can be seen from a sidewalk type survey.
Ahmedabad is located ~250 km from the epicenter and is placed in Zone III of Indian
seismic zoning map. Areas placed in zone III are expected to experience shaking intensity of VII
on MSK scale, which is the same as the shaking intensity experienced by the city during the
earthquake. Hence, damage data of the 2001 Bhuj earthquake (M 7.7) in the city of Ahmedabad
has been used as a basis. 270 buildings that had sustained damage from G0 (no damage) to G5
(collapse) were surveyed in two phases during 2008. The buildings were surveyed for around
twelve vulnerability parameters which were then analyzed statistically to arrive at a methodology
for conducting RVS in Indian buildings as follows:
Performance Score = 80 + 5 x0 + 5 x1 -10 x2 - 5 x3 - 5 x4 - 5 x5 - 5 x6 - 5 x7 - 5 x8
where, x0 = basement, x1 = number of storeys, x2 = poor quality, x3 = plan asymmetry, x4 = plan
irregularity caused by reentrant corners, x5 = open storey, x6 = stub column, x7 = heavy
overhang and x8 = short column
The present work considers only RC frame buildings that are prevalent in urban India.
Similar method needs to be developed for masonry buildings as well.