高性能复合砂浆钢筋网加固高温作用后RC梁二次受力刚度研究  

Stiffness calculation of RC beam strengthened by high performance ferrorcement laminate after fire on second load

作　　者：曾令宏[1] 钟振[1] 

机构地区：[1]湖南大学土木工程学院,湖南长沙410082

出　　处：《建筑结构学报》2016年第3期20-28,共9页Journal of Building Structures

基　　金：国家自然科学基金青年基金项目(51108173)

摘　　要：选取适当的混凝土和钢筋的热工参数及其高温后的力学性能,采用有限元分析软件ANSYS对标准升温条件下RC梁的截面温度场分布进行瞬态热分析,利用高度不变、宽度折减的方式得到受火后的等效截面,并在规范给出的短期刚度计算公式的基础上进行了修正。采用刚度解析法推导了高性能复合砂浆钢筋网加固高温作用后RC梁的刚度计算式,计算时考虑了加固时因未完全卸载和重力引起的应力-应变滞后现象,最后结合现场试验来验证所推导计算式的合理性。试验结果表明,高性能复合砂浆钢筋网可以有效提高构件的抗弯刚度。通过挠度理论计算值与试验值的对比可知,理论值均大于现场试验值,且相差在10%以内,高性能复合砂浆钢筋网加固高温作用后RC梁短期刚度的计算式在实际工程应用中偏于安全。The thermal parameters and mechanical properties of concrete and steel under high-temperature were selected for ANSYS to conduct the transient thermal analysis for the temperature distribution on the cross section of RC beams. The equivalent cross-section was obtained by reducing the width while keeping the height unchanged, and amended by the short-term stiffness formula according to the code. The rigidity formula about the RC beam strengthened with the high performance ferrorcement laminate （HPFL）after fire was deduced with the stiffness analytic method, and the stress-strain lag phenomenon between materials due to the initial load and self weight was considered during the calculation. The rationale of the derived formula was verified by the field test at last. The result shows that the theoretical formula agrees well with the test and HPFL can effectively improve the flexural rigidity of RC beam. The theoretical calculation of deflection values are higher than test values and the deviation is within 10%, which is in the safe range in practical engineering application, and can provide guidance to the structural design with HPFL after fire.

关 键 词：钢筋混凝土梁 复合砂浆钢筋网 加固 受火损伤 二次受力 刚度计算 

分 类 号：TU375.1[建筑科学—结构工程]