有腹板斜裂缝的空心板梁抗剪性能试验研究

Experimental Study on Shear Performance of Hollow Slab Beams with Web Inclined Cracks

摘要:

为探明空心板梁的梁端腹板斜裂缝对结构性能的影响，依托上海外环高速泰和路桥修复养护工程对拆除的空心板梁进行抗剪静载试验，试验参数主要包含：初始病害、剪跨比、横向偏载。试验结果表明：试验梁的剪切破坏具有脆性特征，最终破坏时均发生了钢绞线的滑移。试验梁的抗剪承载力的实测平均值是规范的理论抗力计算值的1.44倍，是荷载效应计算值的1.57倍。有腹板斜裂缝病害的空心板梁的抗剪能力平均下降了12.2%。在偏载作用下，空心板梁的承载力较正载作用下的空心板梁平均下降了17.3%。在桥梁的运维过程中，应重点关注斜裂缝病害的发展及桥梁横向联系病害。结合病害的严重程度、桥梁运营荷载情况、施工条件、社会经济影响等因素，从提高桥梁整体性和提高单梁自身承载力两个方面选择合适的措施提高桥梁的安全性。

Abstract:

To investigate the impact of web inclined cracks at the beam ends on the structural performance of hollow slab beams, a shear static loading test is conducted on hollow slab beams removed from the Taihe Road Bridge Repair and Maintenance Project of the Outer Ring Expressway in Shanghai. The main test parameters include the initial damage, shear span ratio and transverse eccentric load. The test results indicate that the shear failure of the test beams has the brittle characteristics, with slippage of the steel strands occurring at the final failure stage. The measured average value of the shear bearing capacity of the test beam is 1.44 times the theoretical resistance calculation value specified in the code, and is 1.57 times the calculated value of the load effect. The shear resistance capacity of hollow slab beams with web inclined crack disease decreases by an average of 12.2%. Under eccentric loading, the bearing capacity of hollow slab beams decreases by an average of 17.3% compared with that under normal loading. During the bridge operation and maintenance process, the particular attention should be paid to the development of diagonal crack diseases and the lateral connection diseases of bridges. Combined with the factors such as the severity of the damage, operational load conditions of bridge, construction conditions, and socio-economic impact, the appropriate measures should be taken to improve the safety of the bridge by enhancing both the overall integrity of the bridge and the load-bearing capacity of individual beams.