带楼板钢筋混凝土T形梁火灾下(后)温度场研究

Temperature distribution of reinforced concrete T-shaped beam with slabs under(after) three-side fire exposure

为了进一步研究I S O-8 3 4标准火灾作用下三面受火带楼板钢筋混凝土T形梁的温度场分布,采用A B A Q U S非线性有限元软件建立带楼板钢筋混凝土T形梁的温度场分析模型,在此基础上,在不同T形梁截面尺寸和高宽比等情况下,对考虑升、降温全过程的温度场和火灾后温度场分布进行研究。研究结果表明:楼板对钢筋混凝土梁的截面升温有较大影响,T梁腹板宽度影响相邻楼板的温度场分布;考虑升温和降温全过程后,内部混凝土达到最高温度的时间明显滞后,距离受火面越远,升温滞后越严重;火灾后的混凝土截面温度场分布与升温或降温过程中任一时刻的温度场有较大不同,进行火灾后钢筋混凝土T形梁的力学性能分析时,应采用火灾后(历史最高)温度场。

To study the temperature distribution of reinforced concrete （RC） T-shaped beams combined with RC slabs subject to ISO-834 standard fire, of which three-side surfaces were heated, finite element （FE） models of the RC T-shaped beam with slabs were built using the nonlinear software ABAQUS. Parametric analysis was carried out on both the temperature distribution of the T-shaped beams with different sectional sizes and height-to-width ratios and the temperature distribution of the T-shaped beams subjected to the ISO-834 standard fire including cooling phase or after fire. The results show that RC slabs have large influence on the temperature distribution of T-shaped beams. The width of T-shaped beams has effect on the temperature rising in adjacent RC slabs. The fire duration time of inside concrete reaching the maximum temperature delays with the distance from the heated surface. The temperature distribution of T-shaped beams is quite different from that under high temperature （including cooling phase）, so in the study of the mechanical behavior of the RC T-shaped beam, the temperature distribution after fire （the highest history temperature） should be used.