CALCULATION OF ULTIMATE BEARING CAPACITY OF FOUR KINDS OF TWO-WAY SLABS WITH DIFFERENT BOUNDARIES UNDER FIRE

To further understand the calculation method of ultimate bearing capacity of two-way slabs under different boundary conditions, four kinds of two-way slabs with different boundaries are studied by the grounds of existing research. Based on the plate balance method and energy method, an ultimate bearing capacity calculation formula for reinforced concrete two-way slabs with four different boundaries under fire is developed, which is simply supported on three sides and clamped on one side, simply supported on one side and clamped on other three sides, simply supported on two long sides and clamped on two short sides, and simply supported on two long sides and clamped on two long sides. The influence of membrane effect under a large deflection is considered in the formula, the calculated results and the experimental results have a high consistency. The calculated results of the two methods have a deviation of about 2%. Based on integrating other formulas, the general formulas for calculating the ultimate bearing capacity of various boundary two-way slabs under fire are proposed, which can provide a reference for engineering design and further research.