钢筋混凝土T梁疲劳性能试验研究

Experimental Research on Fatigue Behavior of Reinforced Concrete T-beam

为了获取钢筋混凝土T梁的疲劳损伤发展规律,在实验室对5片试验梁进行了等幅疲劳加载试验研究。试验梁呈现出明显的疲劳损伤3阶段规律:疲劳试验前期和后期损伤发展均较快,但疲劳试验中期损伤发展相对稳定。疲劳损伤破坏为钢筋突然的脆性破坏。裂缝数目、宽度及高度发展可划分为快速发展、稳定和破坏3个阶段。接近疲劳破坏时除一至两条主裂缝继续扩展外其余裂缝停止增长并逐渐闭合,最终在主裂缝处疲劳断裂。试验梁的挠度发展、钢筋与混凝土的应变发展增量在疲劳循环初期时增长比较显著,随着疲劳荷载循环次数的增加,增长速率趋缓而进入相对稳定的发展阶段;临近破坏时又发生了较大幅度的增长。得到了钢筋混凝土T梁的S-N曲线。

The fatigue fatigue damage damage equiamplitude fatigue loading experiment on five test beams are carried out to acquire the development regulation of steel reinforced T-beams. An obviously 3-stage regular pattern of is presented during experiment： the damage developed rapidly during the previous period and later period of the experiment, but it developed relatively stable in middle stage. It shows that （1） the beam destroyed through steel bar＇s suddenly brittle break; （2） the development of crack＇s number, width and height can be divided to rapid progress, stable and destroy stages; （3） almost all of the cracks＇ propagation are stopped and closed and the beam are fatigue destroyed at the area of main crack at last, except one or two main cracks spread sequentially when the test beams near to be destroyed ; （4） the deflection of the test beam and the strain increment of steel bars and concrete increased rapidly during the previous period of fatigue cycle, with the increase of fatigue cycle, the increasing rate slowed down and stayed relatively stable in middle stage, but it increased rapidly when near to be destroyed. The S - N curve of steel reinforced concrete T-beam is acquired.