Abstract:
Latest advancements in the domain of fire safety have triggered a shift from conventional
prescriptive to performance based approaches. Also, in the era of modern computational
technology, mathematical models prove to be a more efficient way of quantifying structural
performance rather than full scale testing. Analysing structural elements i.e., beams and
columns separately gives an insight of thermal profile and strength & stiffiess degradation
during fire accident. Considerable amount of work has been done on material properties at
elevated temperatures. However, a large variation exists in available material properties at
elevated temperatures. This makes it imperative to conduct comparative studies in order to
ascertain their suitability. Validation against experimental results is a very important concern.
In this dissertation, an attempt has been made to compare the effect of different constitutive
models available in literature on the thermal response of reinforced concrete elements and
hence arrive at optimum modeling strategies.
Performance based sequentially coupled thermal stress analyses was conducted on RC
elements using the commercial general purpose finite element analysis (FEA) package
ABAQUS. For axial members, the effect of load level and confinement was also studied. It
was observed that including effect of confinement improves accuracy of results and is more
important at higher load levels in axial members. Residual behaviour of flexural members was
simulated wherein the importance of modelling the complete heating and cooling cycle rather
than employing residual models on undamaged specimen was also elucidated. Results
improved significantly in case of flexural members when the whole sequence of events was
modelled. Further, gap areas were also identified for future studies in this area
