装配式预应力混凝土框架梁柱压接接缝抗剪性能试验与承载力计算方法研究

CALCULATION METHOD FOR SHEAR BEHAVIOR AND SHEAR STRENGTH OF POST-TENSIONED GROUTING CONNECTION OF BEAM-TO-COLUMN JOINT IN PRECAST PRESTRESSED CONCRETE FRAME STRUCTURES

梁柱压接接缝抗剪性能对保证装配式预应力混凝土框架整体性能至关重要,为研究预压应力作用和梁端弯矩作用对其抗剪性能和承载力的影响,进行了11个预应力压接接缝试件和3个预应力压接接缝受弯矩作用试件的抗剪性能试验。试验结果表明:预加力能显著地增加接缝的抗剪承载能力,截面预应力分布对承载力有明显影响;预压应力均匀分布时,其极限剪应力和残余剪应力与均匀压应力之间均呈线性正相关关系;预压应力偏心分布时,预加力偏心距越大,其极限承载力较相同均匀预加力接缝降低越显著;接缝受梁端弯矩作用时,弯矩使接缝截面压力增加,接缝截面开裂前,压力合力偏心距减小,进而提高接缝的抗剪承载力;但接缝截面开裂后,压力合力偏心距增加,其抗剪承载力出现降低,接缝截面处于受弯极限状态时,抗剪承载力降至最低。提出了梁柱压接接缝考虑预应力作用和梁端弯矩作用的抗剪承载力计算方法。

The shear behavior of post-tensioned grouting connections is important to ensure the overall performance of precast prestressed concrete frame structures.In order to study the influence of the prestress and the beam end bending moment on the shear behavior of post-tensioned grouting connections,shear tests were carried out on eleven specimens with three specimens subjected to specific bending moment.The results show that the post-tensioning can significantly increase the shear strength of the connection,and the prestress distribution influences the shear strength.The ultimate shear strength and the residual shear strength increase linearly when the prestress of the connection is uniformly distributed.When the prestress of the connection is eccentrically distributed,the greater the eccentricity of the resultant prestressing force,the greater the reduction in the ultimate shear strength of the connection.When the post-tensioned grouting connection is subjected to the beam end bending moment,the bending moment increases the compressive resultant force of the cross-section,thereby improving the shear bearing capacity of the connection before cracking.As the bending moment increases,the eccentricity of the compression resultant force increases,and the shear strength of the connection decreases after cracking,especially when the connection is in the bending limit state and the shear strength decreases to the minimum.The calculation method of the shear strength of the connection considering the effect of the prestress and the beam end bending moment was proposed.