初期受冻对钢筋混凝土梁受弯性能的影响

Analysis on Bending Behavior of RC Beams after Sustaining Early Frost

目的对初期受冻作用后,混凝土强度等级为C30、C50的钢筋混凝土梁受弯性能进行定量分析,为建筑结构设计和耐久性检测提供参考.方法对初期受冻90 d、120 d,混凝土强度等级分别为C30、C50的混凝土梁进行室外受冻试验,将试验结果与对比组进行分析比较,并运用软件对数据进行拟合.结果 C30钢筋混凝土梁初期受冻120 d后开裂荷载、屈服荷载和极限荷载相对下降了28.65%、39.24%和38.81%;90 d后开裂荷载、屈服荷载和极限荷载均下降了1.24%、5.72%和4.4%.C50钢筋混凝土梁初期受冻120 d开裂荷载、屈服荷载和极限荷载相对下降了2%、13.5%和31.3%;90 d钢筋混凝土梁的开裂荷载、屈服荷载和极限荷载均下降了0.1%、0.4%和4.8%.结论初期受冻作用后梁仍然符合平截面假设.通过拟合得出的钢筋混凝土梁在初期受冻作用后抗弯承载力计算模型可以用于实际工程计算和分析.

Bending behavior of RC beams w ith concrete strength level C30 and C50 after sustaining early frost w as analyzed in this paper,in order to provide some references for structural design and durability test. Frost tests of beams w ith concrete C30 and C50 for 90 and 120 days w ere carried out and compared w ith comparison groups. The obtained data w ere fitted by softw are. Results show that the cracking load,yield load and ultimate load of RC beam w ith concrete C30 relatively decrease about 28. 65%,39. 24% and 38. 81% after 120 days early frost; but after 90 d early frost they decrease about 1. 24%,5. 72% and 4. 4%,respectively. The corresponding values for 120 d and 90 d early frost w ith concrete C50 are 2%,13. 5%,31. 3% and 0. 1%,0. 4%,4. 8%,respectively. It is found that the plane-section assumption of beam is also applicable after sustaining early frost. Conclusion is that the calculated model w ith fitting data for bending behavior can be used in practical engineering calculation and analysis.