A proven beam-track contact model was used to analyze the track-structure interaction of CWR (continuously welded track) on bridge. Considering the impact of adjacent bridges, the tower-cable-track-beam-pier-pile fini...A proven beam-track contact model was used to analyze the track-structure interaction of CWR (continuously welded track) on bridge. Considering the impact of adjacent bridges, the tower-cable-track-beam-pier-pile finite element model of the cable-stayed bridge was established. Taking a bridge group including 40-32m simply-supported beam and (32+80+112)m single-tower cable-stayed bridge and 17-32m simply-supported beam on the Kunming-Shanghai high-speed railway as an example, the characteristics of CWR longitudinal force on the cable-stayed bridge were studied. It is shown that adjacent bridges must be considered in the calculation of the track expansion force and bending force on cable-stayed bridge. When the span amount of adjacent bridges is too numerous, it can be simplified as six spans; the fixed bearing of adjacent simply-supported beams should be placed on the side near the cable-stayed bridge; the track expansion device should be set at the bridge tower to reduce the track force near the bridge abutment.展开更多
桥梁工程是公路建设碳排放的主要环节,T梁桥作为公路项目标准化制造的重要结构形式,掌握其碳排放特征和规律,有助于公路低碳建设和管理。研究采用排放因子法对23座典型T梁桥进行碳排放测算,划定了公路T梁桥建设边界范围,确定了碳排放测...桥梁工程是公路建设碳排放的主要环节,T梁桥作为公路项目标准化制造的重要结构形式,掌握其碳排放特征和规律,有助于公路低碳建设和管理。研究采用排放因子法对23座典型T梁桥进行碳排放测算,划定了公路T梁桥建设边界范围,确定了碳排放测算功能单位,测算了各工程部位的碳排放强度,开展了参数敏感性分析和相关性分析,并提出了基于桥梁长度的桥梁主要结构碳排放估算模型。通过测算结果可知,公路T梁桥建设碳排放强度为8927.13 t CO_(2)e/(km·lane),变化区间为4002.64~9871.74 t CO_(2)e/(km·lane),其中间接碳排放占比为98.28%~99.13%,而直接碳排放为6820.99 t CO_(2)e。桥梁建设约86%碳排放主要集中在预应力T梁和桩基础,碳排放强度分别为1.23 t CO_(2)e/m^(3)、0.68 t CO_(2)e/m^(3);约95%来源于水泥、钢材、回旋钻机和交流电弧焊机。敏感性分析表明,当水泥、钢材、电力、化石燃料碳排放因子变化±(10%~30%)时,碳排放变化分别为±(4.77%~14.32%)、±(4.24%~12.74%)、±(0.57%~1.72%)、±(0.14%~0.43%)。相关性分析表明,桥梁主要工程部位的碳排放受桥梁规模影响较大,可基于桥梁长度快速估算T梁桥整体和各工程部位的碳排放。对此,项目管理者可通过低碳采购等方式降低间接碳排放;可通过优化加工工艺和施工方案等方式,在工程活动中节约材料、降低能耗;可通过降低用量和碳排放因子多种组合方式,对主要材料和能源进行综合减碳。相关结果可为公路建设项目的低碳管理及相关研究提供详实的数据支持和节能降碳措施建议。展开更多
The track geometry is a critical factor that affects the running safety and riding comfort of trains moving on a high-speed railway bridge.This study addresses the mapping relationship between the track deformation an...The track geometry is a critical factor that affects the running safety and riding comfort of trains moving on a high-speed railway bridge.This study addresses the mapping relationship between the track deformation and lateral deformations of bridges.Equilibrium equations and natural boundary conditions of the track-bridge system are established based on the energy variational principle,and an analytical solution is derived for the track deformation accounting for lateral bridge deformations.A five-span simply-supported bridge with continuous welded rail has been selected as the case study.The mapping rail deformations are compared to the finite element results,and both results agree well with each other,validating the analytical method proposed in this paper.The influence factors on the mapping rail deformation are further evaluated.Results show that the mapping rail deformation is consistent with the girder displacement at the area that is away from the girder ends when the flexural stiffness ratio between the track and the bridge girder is low.The interlayer stiffness has a significant effect on the mapping rail deformation when the track flexural stiffness is of a high value.展开更多
基金Project(51178469) supported by the National Natural Science Foundation of China
文摘A proven beam-track contact model was used to analyze the track-structure interaction of CWR (continuously welded track) on bridge. Considering the impact of adjacent bridges, the tower-cable-track-beam-pier-pile finite element model of the cable-stayed bridge was established. Taking a bridge group including 40-32m simply-supported beam and (32+80+112)m single-tower cable-stayed bridge and 17-32m simply-supported beam on the Kunming-Shanghai high-speed railway as an example, the characteristics of CWR longitudinal force on the cable-stayed bridge were studied. It is shown that adjacent bridges must be considered in the calculation of the track expansion force and bending force on cable-stayed bridge. When the span amount of adjacent bridges is too numerous, it can be simplified as six spans; the fixed bearing of adjacent simply-supported beams should be placed on the side near the cable-stayed bridge; the track expansion device should be set at the bridge tower to reduce the track force near the bridge abutment.
文摘桥梁工程是公路建设碳排放的主要环节,T梁桥作为公路项目标准化制造的重要结构形式,掌握其碳排放特征和规律,有助于公路低碳建设和管理。研究采用排放因子法对23座典型T梁桥进行碳排放测算,划定了公路T梁桥建设边界范围,确定了碳排放测算功能单位,测算了各工程部位的碳排放强度,开展了参数敏感性分析和相关性分析,并提出了基于桥梁长度的桥梁主要结构碳排放估算模型。通过测算结果可知,公路T梁桥建设碳排放强度为8927.13 t CO_(2)e/(km·lane),变化区间为4002.64~9871.74 t CO_(2)e/(km·lane),其中间接碳排放占比为98.28%~99.13%,而直接碳排放为6820.99 t CO_(2)e。桥梁建设约86%碳排放主要集中在预应力T梁和桩基础,碳排放强度分别为1.23 t CO_(2)e/m^(3)、0.68 t CO_(2)e/m^(3);约95%来源于水泥、钢材、回旋钻机和交流电弧焊机。敏感性分析表明,当水泥、钢材、电力、化石燃料碳排放因子变化±(10%~30%)时,碳排放变化分别为±(4.77%~14.32%)、±(4.24%~12.74%)、±(0.57%~1.72%)、±(0.14%~0.43%)。相关性分析表明,桥梁主要工程部位的碳排放受桥梁规模影响较大,可基于桥梁长度快速估算T梁桥整体和各工程部位的碳排放。对此,项目管理者可通过低碳采购等方式降低间接碳排放;可通过优化加工工艺和施工方案等方式,在工程活动中节约材料、降低能耗;可通过降低用量和碳排放因子多种组合方式,对主要材料和能源进行综合减碳。相关结果可为公路建设项目的低碳管理及相关研究提供详实的数据支持和节能降碳措施建议。
基金Project(2021RC2011)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProjects(U1934207,52178180)supported by the National Natural Science Foundation of ChinaProject(2021M703648)supported by the China Postdoctoral Science Foundation。
文摘The track geometry is a critical factor that affects the running safety and riding comfort of trains moving on a high-speed railway bridge.This study addresses the mapping relationship between the track deformation and lateral deformations of bridges.Equilibrium equations and natural boundary conditions of the track-bridge system are established based on the energy variational principle,and an analytical solution is derived for the track deformation accounting for lateral bridge deformations.A five-span simply-supported bridge with continuous welded rail has been selected as the case study.The mapping rail deformations are compared to the finite element results,and both results agree well with each other,validating the analytical method proposed in this paper.The influence factors on the mapping rail deformation are further evaluated.Results show that the mapping rail deformation is consistent with the girder displacement at the area that is away from the girder ends when the flexural stiffness ratio between the track and the bridge girder is low.The interlayer stiffness has a significant effect on the mapping rail deformation when the track flexural stiffness is of a high value.
