复合配筋预应力混凝土管桩受弯与受剪性能试验研究

Experimental Study on Flexural and Shear Behaviors of Pre-stressed Concrete Pipe with Hybrid Reinforcement

通过开展2种常用规格的复合配筋预应力混凝土管桩(PRC管桩)的受弯和受剪性能试验,对比2种规格PRC管桩的受力特性和破坏特征,分析非预应力钢筋对结构承载力和破坏过程的影响。受弯试验结果表明:非预应力钢筋的加入改善了预应力混凝土管桩(PHC管桩)的承载性能,其抗裂弯矩和极限弯矩均有显著提高,分别是规范参考值的1.1倍和1.2倍;非预应力筋配筋率对管桩受弯时的破坏特征、裂缝数及裂缝分布跨度有一定影响。受剪试验结果显示:预应力筋配筋率对复合配筋预应力混凝土管桩的破坏形态影响较小;2根试验桩的破坏过程相似,均是从加载点与支座之间剪弯段优先出现主裂缝,与桩长方向大致为20°夹角向跨中水平延伸,形成贯通面;主裂缝向支座外发散式萌生裂缝,向管桩上下表面延伸扩展,呈"八"字形。

Two common types of pre-stressed concrete pipe piles with hybrid reinforcement(PRC pile)were studied,hence effect of non-prestressed steels on the flexural and shear capacities and failure characteristics was obtained and analyzed.The flexural test results showed that non-stressed steels evidently improved cracking moment and ultimate moment of pre-stressed concrete pipe pile(PHC pile),with 1.1 times and 1.2 times than those of PHC piles respectively.The non-prestressed reinforcement ratio had a certain influence on the failure characteristics,crack number and crack distribution span of PRC piles.On the other hand,the shear test results showed that failure process of two types of pipe piles was similar,cracking from bearing and extending to the loading point of vertical surface by approximately20 degrees direction,finally forming through surface of pipe piles.