单伸缩缝桥梁连续配筋接线路面温度效应

Temperature Effect for Reinforced Approach Pavement of Single Expansion Joint Bridge

为扩大全无缝桥梁的使用范围,提出一种适用于桥长小于300m的桥梁形式——单伸缩缝桥梁。接线路面是单伸缩缝桥梁中吸纳主梁温度变形的重要构件,基于混凝土粘结-滑移理论,推导了温降作用下接线路面的应力及裂缝宽度计算公式,同时开展了模拟温降作用的足尺模型试验。研究结果表明:混凝土应力的理论计算值略大于试验值,最大相对误差为-6.88%,理论计算值能较准确地反映实际受力状况;接线路面的裂缝均出现在锯缝处,最大裂缝宽度为0.262mm,远小于容许值0.5mm,接线路面有较好的吸纳变形能力;接线路面混凝土上、下表面存在应力差,最大应力差为0.188MPa,设计时推荐采用分节段配筋的方法。

In order to extend the application of fully jointless bridge, a new type of single expansion joint bridge （SEJB） was proposed, which would be expected to be applied to bridges with length less than 300 m. Some deformation in the girder due to thermal effect would be absorbed by reinforced approach pavement in the SEJB. Based on the bonding-sliding theory of concrete, formulas for calculating the stress distribution in pavement under decreasing ambient temperature were deduced, as well as the formulas for calculating the crack width. Meanwhile, a full-scale model test was conducted, to simulate the mechanical behavior of pavement under temperature decreasing. The results show that the theoretical calculation results are slightly larger than the tested results, with the maximum difference of --6. 88%, and the theoretical calculation results can accurately reflect the actual mechanical state of pavement; cracks appear at saw kerfs in experiment, and the maximum crack width is 0. 262 mm, much less than the allowable crack width （0. 5 mm）, which indicates that the reinforced approach pavement can absorb the deformation of girder greatly; a maximum difference of 0. 188 MPa has been detected between the stresses at the upper and lower surface of the concrete. Therefore, it is recommended that segmental reinforcement should be adopted in design.