连续梁悬臂牛腿病害无损主动加固技术
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摘要
针对某连续梁桥悬臂牛腿出现斜向受力裂缝和下挠变形较大的病害,提出一种增设刚性梁对梁体牛腿端进行部分卸荷的主动加固方法。该方法通过在牛腿位置处的墩顶增设刚性梁,将悬臂牛腿的支座竖向力直接通过刚性梁端部传递到墩顶,以分担悬臂牛腿的部分荷载,减小悬臂牛腿受力。施工中,通过整体同步提升技术将刚性梁准确安装到预定位置,采用PLC同步顶升高精度控制技术完成悬臂牛腿部分荷载转移到刚性梁上的体系转换,达到主动分担悬臂牛腿荷载的目的。监控和荷载试验结果显示,刚性梁与悬臂牛腿整体受力性能良好,显著减轻了原主梁牛腿的负载,提高了牛腿结构的安全储备。
Oblique stress cracks were found in the cantilever brackets of a continuous beam bridge and the downwarping amplitude of the beam was big.An active strengthening method——to add rigid beams to locally remove the loads acting on the beam brackets,is proposed.Rigid beams were added on the top of the piers where brackets were located.By this way,the vertical force in the bearings acting on the cantilever brackets can be transferred to the pier tops directly via the ends of the rigid beams,allowing part of the loads on the cantilever brackets to be shared by the rigid beams,hence,reducing the force in the cantilever brackets.In the construction process,the rigid beams were accurately installed to the designed locations by the synchronized integral lifting technique.The PLC synchronized jacking equipment with high-precision control capacity was used to transfer part of the loads on the cantilever brackets to the rigid beams to complete the system transformation,as a result,the loads on the cantilever brackets were actively shared by the rigid beams.The results of the monitoring and control and load tests show that the overall load bearing performance of the rigid beams and the cantilever brackets is good,the rigid beams distinctively reduce the loads on the main beam brackets and improve the safety margin of the brackets.
Oblique stress cracks were found in the cantilever brackets of a continuous beam bridge and the downwarping amplitude of the beam was big.An active strengthening method——to add rigid beams to locally remove the loads acting on the beam brackets,is proposed.Rigid beams were added on the top of the piers where brackets were located.By this way,the vertical force in the bearings acting on the cantilever brackets can be transferred to the pier tops directly via the ends of the rigid beams,allowing part of the loads on the cantilever brackets to be shared by the rigid beams,hence,reducing the force in the cantilever brackets.In the construction process,the rigid beams were accurately installed to the designed locations by the synchronized integral lifting technique.The PLC synchronized jacking equipment with high-precision control capacity was used to transfer part of the loads on the cantilever brackets to the rigid beams to complete the system transformation,as a result,the loads on the cantilever brackets were actively shared by the rigid beams.The results of the monitoring and control and load tests show that the overall load bearing performance of the rigid beams and the cantilever brackets is good,the rigid beams distinctively reduce the loads on the main beam brackets and improve the safety margin of the brackets.
引文
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[3]邬晓光,杜仕朝,殷任宏.大跨PC连续刚构桥正截面最小压应力储备值研究[J].世界桥梁,2016,44(2):64-67,72.
[4]刘殿元,齐铁东,向学建.港珠澳大桥九洲航道桥辅助墩支点顶升受力分析[J].桥梁建设,2019,49(2):113-118.
[5]汪迎红.钢-混组合梁负弯矩区应变控制研究[J].世界桥梁,2015,43(4):131-134.
[6]吕宏奎.某重载铁路连续刚构桥底板崩裂加固设计[J].桥梁建设,2019,49(2):71-76.
[7]马振栋,刘安双.控制大跨连续刚构桥梁过度下挠的技术措施[J].桥梁建设,2015,45(2):71-76.
[8]徐刚年,王有志,王世民,等.东明黄河公路大桥主梁加固关键施工技术[J].桥梁建设,2017,47(5):101-106.
[9]刘其伟,王成明,许映红,等.自平衡反压式单支座更换技术研究[J].公路交通科技,2017(10):83-91.
[10]郑双杰,刘玉擎.钢牛腿支承锚梁型索塔锚固结构传力机理分析[J].中国铁道科学,2014,35(5):19-23.
[11]金辉,徐岳,郑求才,等.型钢-混凝土组合加固技术在空心板桥中的应用[J].桥梁建设,2017,47(1):114-118.