台后设置拱形结构的无缝桥梁整体受力性能

Overall mechanical performance of jointless bridges with arch structure behind abutment

基于实际连续预应力混凝土无缝桥结构的试设计,提出了一种台后设置拱形结构的新型整体式无缝桥梁。通过建立该新型结构的三维杆系计算模型与实体有限元模型,考虑桩基与桩周土之间相互作用,并按相似比原则设计半桥有机玻璃模型试验以验证模拟方法的正确性。采用经验证的数值模型建立台后设置拱形结构的全桥杆系模型与实体模型,分析矢跨比与桩长对桥梁整体受力性能的影响。分析结果表明:模型试验的位移和应力值与杆系模型差异分别为8%和21%,与实体模型差异分别为-3%和5.3%;随着矢跨比的增大、桩长的减小,拱脚所受的水平约束减小,拱顶的竖向位移相对减小,主梁所受的轴力逐渐减小,弯矩变化范围也逐渐降低。因此,选择桩长较短、矢跨比较大的无缝桥梁的整体受力性能更加优越。

Based on the trial design of the actual continuous prestressed concrete jointless bridge structure,the new type of integral jointless bridge with arch structure behind abutment was proposed.The threedimensional beam-truss calculation model and the solid finite element model of the new structure was established.The effect of the interaction between the pile foundation and the soil around the pile was considered,and the half bridge organic glass model test was designed according to the principle of similarity ratio to verify the correctness of the simulation method.The verified numerical model was used to establish the full bridge beam-truss model and the full bridge solid model for the arch structure behind the abutment,and the effect of rise-span ratio and pile length on the overall mechanical performance was analyzed.The analysis results show that:The displacement and stress values of the model test are 8%and 21%different from those of the beam-truss model,and-3%and 5.3%different from those of the solid model.With the increase of rise-span ratio,the horizontal constraint on the arch foot decreases,the vertical displacement of the arch crown decreases relatively,the axial force on the main beam decreases gradually,and the bending moment variation range also decreases slightly,the horizontal force generated by the temperature is more transmitted to the arch structure behind the abutment.With the reduction of the pile length,the vertical displacement of the arch crown decreases,the shear force at the pile top decreases relatively,the axial force on the main beam decreases gradually,and the range of bending moment changes slightly decreases.Considering the actual foundation conditions,the jointless bridges with shorter pile length and larger risespan ratio has better overall mechanical performance.