贾毅++廖平++王永宝++赵人达

摘要：为了解某宽跨比较大的三跨简支斜桥在正常运营状态下的安全性和不利状态下的承载力，基于试验方法研究了在偏载和中载等不利荷载工况下的主梁应力和变形。通过脉动试验、无障碍行车试验、有障碍行车试验研究了该桥的自振频率、不同行车速度下的变形响应及跳车试验下的冲击作用，将测试结果与有限元结果进行了对比。结果表明：跨中截面中载为最不利荷载工况，在不利荷载工况下，实测应变和挠度均小于计算值，主梁变形和混凝土应力均满足规范要求；当行车速度在30 km·h-1以内跑车试验时，各跨冲击系数为1.094～1.192；当行车速度为10 km·h-1跳车试验时，各跨冲击系数为1.147～1.195；该桥的结构强度和刚度具有一定的富裕度，能较好地满足实际运营状况。

关键词：荷载试验；简支斜桥；效率系数；自振特性；校验系数；承载能力

中图分类号：TU312文献标志码：A

Research on Bearing Capacity of Threespan Simply Supported

Skew Bridge Based on Load TestJIA Yi， LIAO Ping， WANG Yongbao， ZHAO Renda

（School of Civil Engineering， Southwest Jiaotong University， Chengdu 610031， Sichuan， China）Abstract： In order to understand the security under normal operation state and the carrying capacity under adverse conditions of a threespan simply supported skew bridge with large widthspan ratio， the stress and deformation of the main beam under the condition of unbalance load and medium load were studied based on the test method. The natural vibration frequency， deformation response under different diving speeds and the impact action of bridge under vehicle jump test were studied through pulse test， barrierfree driving test and obstacle driving test， and the test results were compared with the finite element results. The results show that the midspan section under medium load is the most unfavorable load condition. The measured values of strain and deflection are less than the calculated values under the unfavorable load conditions， and the deformation of the main beam and the stress of concrete both meet the requirements of the specification. When the speed is within 30 km·h-1 in barrierfree driving test， the impact coefficients of each span are 1.094 to 1.192. When the speed is 10 km·h-1 in obstacle driving test， the impact coefficients of each span are 1.147 to 1.195. The structural strength and stiffness of the bridge are rich， which can meet the actual operating conditions well.

Key words： load test； simply supported skew bridge； efficiency coefficient； natural vibration characteristic； calibration coefficient； carrying capacity

0引言

隨着中国国民经济的日益增长，公路交通事业得到迅猛发展，桥梁工程又是公路交通的咽喉，其使用功能的好坏直接影响整条线路的畅通。由于中国许多早年建成的桥梁其设计荷载等级偏低，并且绝大多数桥梁未进行耐久性设计，受运营荷载影响，许多桥梁已出现各种病害和损伤，迫切需要对这些桥梁进行承载能力评定，以保证桥梁结构的运营安全和满足耐久性要求[13]。

现场荷载试验是评定桥梁承载能力的主要技术手段之一，即通过在实际结构上采用与设计荷载等效的试验荷载进行加载，测试桥梁各主要受力构件的作用效应，并与理论计算结果进行对比，从而推定结构的安全储备和可靠度[4]。……