Response of RC
frames to Unconfined Surface Blast loads across Varied Structural Aspect Ratios
Vincent Jasmine George, Ponnada Markandeya Raju and Mishra Siba Prasad
Disaster Advances; Vol. 18(3); 18-30;
doi: https://doi.org/10.25303/183da018030; (2025)
Abstract
Urban sprawl in India leads to have more variety of buildings with different geometries,
plan and structural aspect ratios and irregularities. Geometry (i.e. size and shape)
is one of the perilous factors that affects the response of the structure against
seismic and blast loads. It significantly affects the dynamic performance of the
structure. Blast loads can cause catastrophic damage to the structures leading to
huge life loss in addition to property loss. Hence, it is essential to understand
the behavior of structures with different geometries and the influence of structural
aspect ratio on the performance of structures subjected to explosive loads. The
present study is focused on study of variation in the response of RC framed structures
with varied structural aspect ratios against unconfined surface blast loads. Six
different regular reinforced concrete frame models having structural aspect ratios
(i.e. H/B) 0.25, 0.375, 0.5, 0.75, 1.0 and 1.5 are considered.
To meet the requirement of proposed structural aspect ratios, two different plinth
areas of 576 sq.m. and 1296 sq.m. and three different numbers of stories of 3, 6
and 12 are taken. Response of these RC frame models is analyzed for three different
blast load intensities having charge weights 500, 1500 and 2500kg TNT at a standoff
distance of 10m. Time history analysis is performed on the above-mentioned RC frames
using a computer software package. From the study, it is evident that low rise buildings
are relatively more affected by unconfined surface blast loads. This impact will
increase further with higher blast intensities.
