双线系杆拱桥对不同列车荷载的适应性分析

以一座跨度为128 m铁路双线系杆拱桥为例,基于TB 3466—2016《铁路列车荷载图式》,在ZK,ZC,ZKH,ZH(Z=1. 3)列车荷载作用下,分析系杆拱结构受力及变形性能,探讨其适应性及控制因素。研究结果表明:主梁结构在4种列车荷载作用下均满足规范要求,在ZK,ZC列车荷载作用下,主梁结构强度及抗裂安全系数均较大,可采用适当减少预应力配置等形式进行优化调整;在ZH(Z=1. 3)列车荷载作用下,拱肋横向稳定安全系数接近限值,且拱肋与拱脚连接位置8 m范围内强度安全系数超规范限值,钢管厚度需增加,表明该桥型控制因素为拱肋结构受力及拱肋横向稳定性;结构刚度均满足规范限值,挠跨比最小值亦达1/5 000,反映了系杆拱桥刚度大的特点;双线系杆拱仅在ZH(Z=1. 3)列车荷载作用下需局部调整结构尺寸,其余均可满足结构受力及变形要求,表现出良好的适应性。

Analysis on Adaptability of Double-tracked Tied Arch Bridge to Different Train Loads

Taking a double-track tied arch bridge with a span of 128 m as an example,based on the TB 3466-2016 Railway Train Load Diagram, the mechanical and deformation properties of tied arch structure were analyzed under the action of ZK,ZC,ZKH and ZH ( Z =1.3) train loads,and its adaptability and control factors were discussed.The analysis results show that the main girder structure meets the requirements of the specif ication under four kinds of train loads.Under ZK and ZC train loads,the strength and safety factor of crack resistance of the main girder structure are relatively large,which can be optimized and adjusted by reducing the prestress allocation appropriately.Under ZH ( Z =1.3) train load,the safety factor of arch rib transverse stability is close to the limit value,and the safety factor of arch rib and arch foot is beyond the specif ication limit within the connecting position of 8 m.The thickness of steel pipe needs to be increased,which indicates that the control factors of the bridge type are the stress of arch rib structure and the transverse stability of arch rib.Structural stiffness is greater than the specif ication limit,and the minimum def lection-span ratio is 1/5 000,which ref lects the characteristics of large stiffness of tied arch bridge.Double-track tied arch only needs to adjust the structure size under ZH ( Z =1.3) train load,the rest can meet the structural stress and deformation requirements,showing good adaptability.