直螺栓连接预制综合管廊接头预紧度试验研究

Experimental Study on Preload of Prefabricated Utility Tunnel Joints with Straight Bolt Connections

通过对3个具有不同预紧度的预制综合管廊螺栓连接接头模型试件进行试验,以研究纵向接头采用直螺栓进行连接的综合管廊接头的破坏形态、受力性能及应变特点。试验结果表明,采用合适预紧度的预制综合管廊螺栓连接接头具有良好的受力性能,其破坏形态为螺杆首先屈服,随后受压区混凝土压碎,极限承载力为设计承载力的1.78倍,结构具有较大的安全余量。而螺栓预紧度过低的试件,在达到螺杆的屈服强度之前,螺杆与螺母发生相对滑移,导致试件失去承载力,其承载力远低于螺栓预紧度合适的试件。

Three model specimens of bolted joint of prefabricated utility runnel with different preload are tested to study the failure mode, mechanical properties and strain characteristics of the joint. The test results show that the bolted joint of prefabricated utility runnel with proper preload has good mechanical properties,and the failure mode is that the screw first yields,then the concrete in the compression zone is crushed,and the ultimate bearing capacity is 1.78 times of the designed bearing capacity. The structure has a large safety margin. When the bolt preload is too low,the screw slips relatively with the nut before the screw yielding,which leads to the loss of the bearing capacity of the specimen,which is much lower than that of the specimen with proper bolt preload.