Fire Resistance Experimental Research On Simply Supported Beam With Hot Rolled Bars Of Fine Grains

The industrial production of fine-grained or ultra-fine grained steel has come into use after decades of study, since the 973 project"A major basic research on new generation of iron materials"started in 1998. The high strength steel has higher performance and relatively lower cost in comparison with the low strength steel, hence extending the application of fine-grained steel bars is greatly important to realize the sustainable development for architecture industry.This paper studies the mechanical properties of hot rolled bars of fine grains (HRBF500) experimentally. The yield strength, modulus of elasticity and tensile stress-strain relationship were tested under key temperatures respectively. The article also test the fire-resistance performance of 8 simply supported beams set HRBF500, and besides, the connection form of load-bearing rebar has been changed in order to investigate whether the change has any influence on the holistic fire-resistance ability. At the same time, a group of beams set common hot rolled bars (HRB400) were experimented to find the difference between two kinds of beams. Based on the experimentation, two broken lines simplified model has been used to calculate the beam's equivalent fire load and ultimate load bearing capacity under high temperature; comparing with the test dates, the beam section temperature filed is simulated by the finite element analysis program ANSYS, and the thermal-structural coupling analysis function has selected to proceed the beam's nonlinear finite element analysis.