Research on Deformation and Failure of Concrete Shear Walls During Cooling After Fire
The structural deformation and failure of reinforced concrete(RC)walls during cooling after one-sided fire was studied by numerical simulations.Heat conduction analysis was carried out by finite ele-ment approximation to obtain the temperature distribution inside the wall,and the nonlinear shooting method was used to iteratively solve the structural model.The model took into account the thermal strain of rein-forced concrete at high temperatures,compressive strain softening,tensile hardening,cracking and steel yielding,and geometric nonlinearity.The effects of transient creep of concrete were explicitly considered.After verifying the validity of the model,the structural deformation and failure mechanism of RC walls dur-ing the cooling after fire was revealed by a numerical example,followed by parametric studies.The results showed that RC wall may buckle in the post-fire cooling stage and its failure time could be earlier than that of the wall subjected to continuous fire.The loss of the strength of materials,the shifting of the neutral axis and the transient creep of concrete were the key factors leading to the post-fire buckling failure.In addi-tion,the wall height,wall thickness and load eccentricity had a significant effect on the structural deforma-tion and failure of RC walls during cooling after fire.The fire resistance of RC walls considering post-fire failure was significantly lower than that of RC walls subjected to continuous fire.The fire resistance of RC shear walls considering post-fire failure is significantly lower than that subjected to continuous fire,failure of RC shear wall during the cooling after fire could occur when the fire lasts for more than 15 minutes.In-creasing the reinforcement ratio has a certain preventive effect on the failure of RC shear wall during the cooling after fire.
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