少筋微弯板组合梁旧桥检测评估及处治技术

为评估少筋微弯板组合梁桥在运营期间的承载能力，并研究合理的处治方案，以某5×16.8 m的钢筋混凝土I型梁+少筋微弯板组合梁桥为研究对象。对该桥外观状况、材质状况进行检测，同时通过承载能力检算、静载试验等进行综合评估，采用综合比对方式确定维修改造方案。结果表明：主梁共计存在239条结构裂缝，裂缝最大宽度为3.14 ㎜，远超规范限值，上部结构承载能力不满足规范要求，且微弯板梁裂缝仍存在持续扩展的趋势。采用更换上部结构为连续钢箱梁形式，保留下部结构，具有工期短、总投资较低等优点，改造后，桥梁运营状况良好。

Detection, Evaluation and Treatment Technology of old Bridge of Composite Beam With Less Reinforcement and Slightly Curved Plate

In order to evaluate the bearing capacity of the composite beam bridge with less reinforcement and slightly curved plate during operation and study the reasonable treatment scheme, a 5×16.8 m reinforced concrete I-beam+slightly curved plate composite beam bridge with less reinforcement is taken as the research object. The appearance condition and material condition of the bridge are tested, and the comprehensive evaluation is made by carrying capacity calculation and static load test, and the maintenance and reconstruction scheme is determined by comprehensive comparison. The results show that there are 239 structural cracks in the main girder, and the maximum width of the cracks is 3.14 mm, which far exceeds the limit value of the code. The bearing capacity of the superstructure does not meet the requirements of the code, and the cracks in the micro-bending plate beam still have a trend of continuous expansion. Replacing the upper structure with continuous steel box girder and retaining the lower structure has the advantages of short construction period and low total investment. After transformation, the bridge operates well.