复杂约束条件下简支转连续梁桥墩顶负弯矩区的力学性能

张成明¹，周国涛¹，张景全¹，李梦轲¹，宋涛²

1.山东省公路桥梁建设集团有限公司，山东 济南  250021；2.山东交通学院交通土建工程学院，山东 济南  250357

摘要：为研究简支转连续体系梁桥的墩顶负弯矩区力学性能，以墩顶支点处转角连续为变形协调条件，采用双线性法和龄期调整有效弹性模量法推导墩顶负弯矩区约束弯矩的解析表达式，将约束弯矩的理论结果与试验结果及美国波特兰水泥协会法、施工技术实验室法的计算结果进行对比。研究结果表明：简支转连续过程中，预应力筋张拉对墩顶负弯矩区影响最大；本文提出的墩顶负弯矩计算方法得到的约束弯矩与试验实测结果及其他两种计算方法的结果基本吻合，表明本文所提方法的精确性较好，能初步估算墩顶负弯矩区是否存在开裂的风险。

关键词：简支转连续梁；负弯矩区；约束弯矩；双线性法；龄期调整有效弹性模量法

Mechanical performance of the negative bending moment zone at the top of continuous beam bridge piers under complex constraints

ZHANG Chengming¹, ZHOU Guotao¹, ZHANG Jingquan¹, LI Mengke¹, SONG Tao²

1. Shandong Road & Bridge Construction Group Co., Ltd., Jinan 250021, China;

2. School of Civil Engineering, Shandong Jiaotong University, Jinan 250357, China

Abstract: To investigate the mechanical properties of the negative bending moment zone (NBMZ) at the pier top of a simply supported to continuous girder, the deformation coordination condition is taken as the continuous rotation angle at the pier top fulcrum. The analytical expression of the restraint bending moment in the NBMZ at the pier top is derived using bilinear method(BM) and age-adjusted effective modulus (AAEM) method. Theoretical analysis are carried out. The results of the proposed method are compared with that of the field experiments and Portland Cement Association (PCA) method and Construction Technology Laboratories (CTL) method. The research results indicate that the tensioning of prestressed reinforcement has the greatest impact on the negative bending moment zone at the pier top during the process of simple supported to continuous girder; The values of the proposed method are in good agreement with the measured experimental values and PCA method and CTL method. This indicates the proposed method BM-AAEM has the high accuracy, which can preliminarily estimate whether there is a risk of cracking in the NBMZ at the top of the pier.

Keywords: simply supported continuous beam; negative bending moment zone; constraint bending moment; bilinear method; age-adjusted effective modulus of elasticity method