高轴压比下预制桥墩承插式连接力学行为试验研究

Experimental study of socket connection for precast column under high axial load

为研究高轴压比下预制桥墩承插式连接的力学行为,通过轴压性能试验,研究连接的受力失效机制,明确影响连接轴压强度的关键设计参数,分析侧剪应力分布与极限值,提出承插式连接侧剪应力计算与墩柱承插深度设计方法。结果表明:采用墩柱表面粗糙化处理的承插式连接轴压强度满足桥墩设计荷载要求;承插式连接轴压强度随墩柱承插深度的增大而增大,且强度增量与承插深度增量呈近似线性关系;承插式连接有效承插深度为总承插深度的2/3,且在有效承插深度内,侧剪应力呈均布状态;随着墩柱表面粗糙度的增大,承插式连接的极限侧剪应力得到显著提升,但当墩柱表面粗糙程度达到6 mm以上时,极限侧剪应力不再提升;根据试验与理论分析结果,提出波纹型墩柱表面极限侧剪应力及满足轴向承载力要求的承插深度计算公式。

To investigate the performance of socket connection for precast column subjected to high axial load,experimental tests were performed,load transfer and failure mechanism of the socket connection was studied,key parameters affecting the axial strength of the connection were revealed,distribution and ultimate magnitude of side shear stress was analyzed,and methodologies for determining the ultimate side shear stress and connection side shear stress were proposed.Results indicated that the connection with intentionally roughened column side surface achieved the axial strength that satisfied the axial design demand.The connection axial strength increased with the increasing of the column embedment length,and the increment of strength had a roughly linear relation with the increment of column embedment length.The effective column embedment length was approximately 2/3 of the total column embedment length,and the distribution of side shear stress was linear within the effective column embedment length.With the increase of the roughness of the column surface,the ultimate side shear stress raised,but the ultimate value became constant once the roughness reached 6 mm.According to the experimental and analytical results,the formulations for determining the ultimate side shear stress and the required column embedment length were developed.