Fire resistance of reinforced concrete bearing walls subjected to all-sided fire exposure

摘要

The fire resistance of concentrically loaded reinforced concreted bearing walls with all-sided fire exposure was theoretically and experimentally investigated. The proposed model for predicting the axial behavior of bearing walls considers complex features of the wall in a fire, such as thermal expansion, change of material properties with temperature and spalling of concrete. Comparison with the experimental observations made for a total of eight reinforced concrete walls showed that the model could reasonably simulate the axial behavior of these walls. Using the model, wall thickness and the level of axial load were identified as major parameters influencing the fire resistance. The accuracy of fire resistance provided in different codes was also reviewed. Based on the model predictions, a practical formula for the fire resistance has been derived in terms of wall thickness and the ratio of axial load to the nominal strength of the wall. A close agreement in fire resistance was observed between the predictions made by the model modified with a reduction factor and those from Eurocode 2.