连续钢箱梁桥顶推施工下导梁设计参数分析

在桥梁工程中,顶推施工时设置导梁具有减少临时墩的数量,增加临时墩之间的跨度等作用。然而目前导梁的设计尚未形成完整的理论体系,按钢结构设计的方法进行导梁的设计较为复杂。该文根据工程实例,以有限元软件计算作为基础,计算在不同导梁长度和不同变截面方案下结构的受力情况,以最不利情况下结构的应力、挠度、稳定性作为评判依据。最终选择36 m的导梁长度,近端2 500 mm,远端1 500 mm的变截面方案,节省7.27%的用钢量,最终计算钢导梁最大竖向挠度为314.6 mm;钢导梁最大正应力为164.4 MPa;钢导梁最大剪应力为32.1 MPa,均符合规范要求。

In bridge engineering,setting guide beams during jacking construction can reduce the number of temporary piers and increase the span between temporary piers.However,at present,the design of the guide beam has not yet formed a complete theoretical system,and the design of the guide beam according to the steel structure design method is more complex.According to an engineering example and based on the calculation of finite element software,this paper calculates the stress of the structure under different guide beam lengths and different variable cross-section schemes,and takes the stress,deflection and stability of the structure under the most unfavorable conditions as the basis for evaluation.Finally,the variable cross-section scheme of 36 m guide beam length,proximal 2 500 mm and distal 1 500 mm is selected,which saves 7.27% of steel consumption.Finally,the maximum vertical deflection of steel guide beam is 314.6 mm,the maximum normal stress of steel guide beam is 164.4 MPa,and the maximum shear stress of steel guide beam is 32.1 MPa,which all meet the requirements of the code.