高墩大跨度刚构桥悬臂施工阶段与成桥地震反应对比  

Comparison of Seismic Response Between Cantilever Construction and Completed Bridge of Large-span Rigid-frame Bridges with High Piers

作　　者：童磊 王东升 石岩[3] TONG Lei;WANG Dongsheng;SHI Yan(School of Civil and Transportation Eng.,Hebei Univ.of Technol.,Tianjin 300401,China;Civil Eng.Technol.Research Center of Hebei Province,Tianjin 300401,China;School of Civil Eng.,Lanzhou Univ.of Technol.,Lanzhou 730050,China)

机构地区：[1]河北工业大学土木与交通学院,天津300401 [2]河北省土木工程技术研究中心,天津300401 [3]兰州理工大学土木工程学院,甘肃兰州730050

出　　处：《工程科学与技术》2022年第5期149-157,共9页Advanced Engineering Sciences

基　　金：国家自然科学基金项目(51778206)。

摘　　要：在中国西部地震危险性较高的地区,建造了许多高墩大跨度的预应力混凝土连续刚构桥。高墩大跨度刚构桥一般采用悬臂施工技术,但因施工周期较长,可能在建设期中遭受地震。为探究强震下处于悬臂施工阶段的刚构桥主梁及桥墩可能发生的震害,以经历汶川地震考验的庙子坪大桥为研究对象,建立最大悬臂T构、边跨合龙后非对称单悬臂T构及成桥连续刚构阶段3种结构体系,模拟悬臂施工静定—单次超静定—多次超静定的转换过程;选取桥址附近台站实测的汶川强震动记录进行时程分析;结合成桥阶段庙子坪大桥的实际震害研究结果,对比强震下3种体系主梁应力及桥墩内力。结果表明:与成桥阶段相比,强震下,处于最大悬臂阶段的墩梁固结处顶板、腹板容易开裂,但其他大部分位置不易开裂;处于边跨合龙阶段的边跨合龙段处顶板和底板、边跨1/5~2/5区域腹板及墩梁固结处顶板和腹板的应力均较大,都容易开裂,但中跨反而不易开裂;虽然两个施工阶段桥墩中高位置处纵桥向弯矩是成桥阶段的两倍以上,但不易开裂;墩顶、墩底易开裂,与成桥反应一致;建议施工期的A类连续刚构桥抗震重要性系数取0.76。研究结果可为地震时,采用悬臂施工技术建造高墩大跨度刚构桥提供参考。In the western regions of China with high seismic risks,many pre-stressed concrete continuous rigid-frame bridges with high piers and long spans have been constructed.Generally,cantilever construction technology is used,but the construction period is long.The bridge may suffer earthquakes during construction.The possible seismic damage to the main beam and pier of the rigid-frame bridges in the cantilever construction stage was explored under the strong earthquake.Based on the Miaoziping bridge,which had undergone the Wenchuan earthquake,three structural systems,i.e.maximum cantilever T-frame,asymmetric single cantilever T-frame of side-span-closure,and continuous rigid-frame of the completed bridge,were established to simulate the transition process of cantilever construction from statically indeterminate to once statically indeterminate to multiple statically indeterminate.The strong motion records near the bridge site during the Wenchuan earthquake were selected as the inputs for time history analysis.Combined with the actual earthquake damage of Miaoziping bridge in the completion state,the main beam stress,and piers internal force of the three system structures were analyzed under the strong earthquake.Compared with the bridge completion stage,the top plate and web at the consolidation of piers and girder were also prone to cracking in the maximum cantilever stage under strong earthquakes,but it was not easy to crack in most other positions;In the side-closure-stage,the(principal)tension stress and(principal)compressive stress were also relatively larger in the top plates and bottom plates near the closing section of side-span,the web near the 1/5 to 2/5 area of the side span,and the top plates and bottom plates near consolidation pier-beam,which were also prone to cracking,but the mid-span was not easy cracking.In the two construction phases,although the longitudinal bending moment at the middle-high position of piers was more than twice that of the completed bridge stage,it was not easy to crack;the top an

关 键 词：高墩大跨度刚构桥 地震反应 箱梁开裂 最大悬臂状态 桥墩开裂 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]