大跨连续钢桁梁桥顶推施工全过程可靠度评估  

Reliability assessment of whole process of incremental launching construction of steel truss bridge

作　　者：闫磊[1,2] 闫金宁 韩恒 梁浩源 许毓耕 YAN Lei;YAN Jin-ning;HAN Heng;LIANG Hao-yuan;XU Yu-geng(School of Highway,Chang’an University,Xi’an 710064,Shaanxi,China;Key Laboratory of Transport Industry of Bridge Detection Reinforcement Technology,Chang’an University,Xi’an 710064,Shaanxi,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]长安大学旧桥检测与加固技术交通运输行业重点实验室,陕西西安710064

出　　处：《长安大学学报（自然科学版）》2024年第4期48-65,共18页Journal of Chang’an University(Natural Science Edition)

基　　金：国家重点研发计划项目(2021YFB1600300);陕西省交通运输厅科研项目(21-63K)。

摘　　要：为评估大跨连续钢桁梁桥顶推施工过程的安全性,通过数值模拟、统计调查和概率分析相结合的方法,从定值和概率两方面对连续钢桁梁桥顶推施工全过程进行分析与评价。首先,基于组合应力识别出顶推全过程的失效候选单元,对失效候选单元的强度和稳定进行定值分析,探明钢桁梁顶推施工全过程的定值安全储备;其次,针对失效候选单元建立强度和稳定的功能函数,分析对应的可靠指标,揭示钢桁梁顶推施工全过程的概率安全储备;最后,对影响可靠指标的不定性参数进行敏感性分析,并根据目标可靠指标提出工程监测建议。研究结果表明:顶推施工全过程主桁各类杆件最大强度承力比均超过60%,其中,二期铺装过程中主桁跨中位置处的下弦杆E46′E45′强度承力比达到了84.8%,相应的稳定承力比为89.9%,材料强度得到充分利用;导梁在顶推施工全过程的最大强度承力比为29.5%,最大稳定承力比为41.8%,导梁定值安全储备较大;梁段顶推施工过程中主桁及导梁各失效候选单元可靠指标均大于5.20,主桁及导梁杆件概率安全储备充足;钢梁合龙过程中上弦杆A56′A55′及下弦杆E46′E45′面内稳定可靠指标分别为3.72和2.72;材料性能变异性对杆件可靠指标影响较大,杆件强度及面内稳定可靠指标随材料变异系数增大呈线性减小;综合定值和概率分析结果给出了顶推施工全过程需要监测的关键杆件,以目标可靠指标为依据,对关键杆件进行了分级,制定了关键杆件监测建议并提出了位移及应力监测预警值。To assess the safety of the incremental launching construction process of long-span continuous steel truss bridge,a combined approach utilizing numerical simulation,statistical investigation,and probabilistic analysis was employed.The entire incremental launching construction process of continuous steel truss bridges from both deterministic and probabilistic perspectives was analyzed and evaluated.Firstly,failure-prone elements throughout the incremental launching process were identified based on combined stress,and their strength and stability were analyzed deterministically,revealing the deterministic safety margin of the incremental launching construction process for steel truss bridges.Secondly,functional relationships for the strength and stability of the failure-prone elements were established,and corresponding reliability indices were analyzed,unveiling the probabilistic safety margin of the incremental launching construction process for steel truss bridges.Lastly,sensitivity analysis was conducted on uncertain parameters affecting the reliability indices,and engineering monitoring recommendations were proposed based on the target reliability indices.The results show that the maximum strength capacity ratio of various members of the main truss during the entire incremental launching process exceeds 60%,with the strength capacity ratio reaching 84.8%and the stability capacity ratio reaching 89.9%at the mid-span location of the main truss during the second-phase paving process,indicating the full utilization of material strength.The maximum strength capacity ratio of the guide beams during the incremental launching process is 29.5%,with a corresponding maximum stability capacity ratio of 41.8%,indicating a significant deterministic safety margin for the guide beams.The reliability indices of failure-prone elements of the main truss and guide beams during the incremental launching construction process are all greater than 5.20,indicating sufficient probabilistic safety margins.During the steel beam closure pr

关 键 词：桥梁工程 顶推施工 有限元 钢桁梁桥 可靠度评价 

分 类 号：U445.5[建筑科学—桥梁与隧道工程]