吊杆更换对九堡大桥主桥受力性能的影响分析

Analysis of Effect of Suspender Replacement on Mechanical Behavior of Main Bridge of Jiubao Bridge

为研究吊杆更换对九堡大桥主桥受力性能的影响,根据该桥结构特点提出12种吊杆更换预案并进行分析。采用ANSYS建立该桥空间有限元模型,分析在不同吊杆更换方案下主桥结构的应力和位移、对拱肋和主梁及对吊杆力的影响。分析结果表明:在正常运营情况下,一跨内吊杆局部更换的数量小于3根时,只对更换吊杆跨的结构内力产生影响;一跨内吊杆局部更换时,对该跨拱肋、主梁及吊杆力的影响随拆除吊杆数量的增加而加大,当结构局部连续拆除的吊杆数量小于3根时,结构受力是安全的,但当局部连续拆除的吊杆数量达到3根时,拱肋下缘的应力超过了规范规定的材料强度容许值。

To study the effect of suspender replacement on the mechanical behavior of the main bridge of the Jiubao Bridge, twelve proposals for the suspender replacement were put forward and analyzed in accordance with the structural characteristics of the bridge. The ANSYS was used to set up the spatial finite element model of the bridge, the structural stress and displacement of the bridge under the different proposals and the effect of the proposals on the arch ribs, main girder and suspender forces were analyzed. The results of the analysis demonstrate that on condition of normal operation of the bridge and in the case that less than 3 nos. of the sus- penders are locally replaced within the range of one span, the suspender replacement will only has effect on the structural internal force of the span with the suspenders replaced. For the span with the suspenders locally replaced, the effect on the arch ribs, main girder and suspender forces will increase with the increase of the removal numbers of the suspenders. In the case that the continu- ous removal numbers of the suspenders in the local part of the structure is less than 3, the me- chanical behavior of the structure is safe, however, in the case that the continuous removal num- bers of the suspenders in the local part is 3, the stress in lower flanges of the arch ribs will exceed the allowable values of material strength as specified in the codes.