预应力RC梁抗火性能试验研究与有限元分析

为了考察预应力钢绞线张拉控制应力和梁的持荷水平两个因素对无粘结预应力混凝土梁抗火性能的影响，基于 ISO834标准升温曲线，对4根无粘结预应力混凝土梁进行恒载升温试验，同时应用ANSYS有限元软件建立无粘结预应力混 凝土梁有限元模型，进行恒载升温过程的有限元数值模拟。结果表明:有限元计算结果与试验结果符合较好；预应力钢 绞线张拉控制应力越大，预应力损失速度越快，梁变形速率越快，耐火性能越差；梁上作用荷载水平越高，跨中挠度越 大，变形速率越快，耐火极限越小。

Experimental study and finite element analysis on fire resistance of pre-stressed RC beams

In order to study the effect of tension control stress of pre-stressed steel strand and load level of beam on the fire resistance performance of unbonded pre-stressed concrete beam, the elevating temperature experiments at constant load of four unbonded pre-stressed concrete beams were conducted based on the ISO834 standard time-temperature curve. A finite element model of unbonded pre-stressed concrete beam was established by ANSYS to conduct the finite element simulation of the elevating temperature process at constant load. The results showed that the calculation results of finite element agree well with the test results. The larger the tension control stress of pre-stressed steel strand, the faster the pre-stress loss rate and the beam deformation rate, and the poorer the fire resistance. The higher the load level on beam, the larger the mid-span deflection, the faster the deformation rate, and the shorter the duration of fire resistance. Key words: pre-stressed concrete beam; high tempera