NUMERICAL SIMULATION AND PRACTICAL CALCULATION METHOD FOR THE SHEAR STRENGTH OF CONCRETE SHORT COLUMNS AFTER EXPOSURE TO 3-FACE HEATING

摘要

A numerical model is developed for the push-over analysis of concrete short columns after exposed to fire, and it is verified by the experimental results of seven columns.The effects of the horizontal force direction, fire duration, axial load ratio, sectional dimension, shear span ratio and stirrup spacing on shear strength of concrete short columns after exposure to 3-face heating were investigated.The average reduction coefficient of the compression strength in concrete sections was calculated, and a practical calculation method for the shear strength of concrete columns after 3-face heating was proposed.The results indicate that: (Ⅰ) the shear strength of concrete short column after fire is well predicted by the established model However, the prediction of the full curve of load-displacement behaviour needs further improvement.(2) The proposed formula provides a certain safety margin and can be used to assess the residual shear strength of concrete columns after 3-face heating.