BCCP外压承载能力原型试验

Prototype test on bearing capacity of BCCP under external load

为了研究钢筋缠绕钢筒混凝土压力管(BCCP)的外压承载能力,设计了三个不同管径的BCCP外压现场原型试验.在管径为1800 mm的BCCP上布置应变片和位移计,揭示各部位的受力变化规律,并建立有限元模型与试验进行验证.试验结果发现BCCP从生产时施加预应力到最终破坏可分为4个阶段:管芯受预应力钢筋环向作用力阶段;两侧管腰处保护层开裂前整管承受外压弹性阶段,对应于试验中外压小于800 kN的阶段,此时各组分应变随外压呈线性增长;管芯顶部和底部受拉开裂阶段,试验中当外压达到1600 kN后,管芯顶部和底部混凝土相继受拉开裂;管芯腰部附近混凝土被压溃阶段.

To study the bearing capacity of bar-wrapped cylinder concrete pressure pipe(BCCP)under external load,tests on three prototype pipes with different diameters were designed.The strain gauges and displacement meters were arranged on the BCCP with diameter of 1800 mm,and the force variation law of each part was obtained.The whole process of failure was verified by finite element simulation and test.Experimental results show that the process from applying prestress in production to ultimate failure can be divided into the following four stages:the concrete core is subjected to the force of prestressed steel bar without protective cover;the whole pipe is in the elastic stage before the protective cover at the waist cracks,corresponding to the stage when the external load in the test is less than 800 kN and the strain of each component increases linearly with the external load;the concrete at the top and bottom of the core is split,and when the external load reaches 1600 kN,the concrete at the top and bottom of the core is split successively;the concrete around the waist of the core is crushed.