张拉螺纹钢对箱梁吊梁孔结构受力的影响

Influence of Tensioned Thread Steel Bar on Structure Stress Around Lifting Holes in Box Girder

在起吊、移动箱梁的过程中,梁体吊梁孔周围普遍会产生开裂现象。吊梁孔横向间距的减小会对梁端受力分配产生不利影响。本文基于现有的简支箱梁竖向加固方法并结合一非标梁的实际工程情况,提出了一种张拉螺纹钢辅助吊梁方法。根据一新建高速铁路简支(箱形)非标梁采用张拉螺纹钢辅助吊梁方法前后的吊梁试验结果,通过对比实测应变与裂缝发展情况,证明该方法有利于减少吊梁过程中梁体开裂的可能性并降低混凝土应力水平。

During the process of lifting and moving box gird,generally there will be cracks around the lifting holes.The decrease of horizontal spacing between lifting holes has adverse inf luence on gird end stress distribution.On the basis of the existing vertical reinforcement methods of simply supported box girder,and combining with the actual engineering situation of a non-standard gird,this paper presents a method to assist lifting gird process by tensioning screw thread steel bar.This method was used on a high speed railway simply supported(box shape)non-standard gird.Lifting gird tests with and without tensioned thread steel bars were carried out.By comparing the measured strain and observed cracks,it is concluded that the method of tensioned thread steel bar may decrease gird crack possibility during lifting gird process and reduce concrete structure stress level.