The steel-concrete composite bridge system with twin girders,referred to as a steel plate composite girder bridge,is widely adopted for short-to medium-span highway bridges due to its ability to enable rapid prefabric...The steel-concrete composite bridge system with twin girders,referred to as a steel plate composite girder bridge,is widely adopted for short-to medium-span highway bridges due to its ability to enable rapid prefabrication and construction in bridge engineering.Considering the structural design of steel plate composite girder bridges,which are wide but shallow in depth,their deck slabs are vulnerable to vertical impacts from vehicle loads.Structural performance may be negatively affected by excessive dynamic displacement of deck slabs.It is difficult to assess the dynamic response of the deck slabs by existing methods,since traditional specifications only use a global impact factor to describe the dynamic effect of moving vehicles on the bridge as a whole,regardless of the local dynamic effect on the deck slabs.Therefore,this study aims to assess the local dynamic effect of moving vehicles on the deck slabs of steel plate composite beam bridges using field tests and finite-element methods.A systematic approach was employed to analyze parameters influencing bridge-vehicle interaction.Additionally,an improved method was presented to calculate the local impact factor and parametric studies were discussed.The findings indicated that the local impact factor of deck slabs is significantly greater than the global impact factor.Road surface roughness is the most significant parameter affecting deck slab dynamic behavior.展开更多
Steel and steel-concrete composite girders are two types of girders commonly used for long-span bridges. However, practice has shown that the two types of girders have some drawbacks. For steel girders, the orthotropi...Steel and steel-concrete composite girders are two types of girders commonly used for long-span bridges. However, practice has shown that the two types of girders have some drawbacks. For steel girders, the orthotropic steel deck (OSD) is vulnerable to fatigue cracking and the asphalt overlay is susceptible to damage such as rutting and pot holes. While for steel-concrete composite girders, the concrete deck is generally thick and heavy, and the deck is prone to cracking because of its low tensile strength and high creep. Thus, to improve the serviceability and durability of girders for long-span bridges, three new types of steel-UHPC lightweight composite bridge girders are proposed, where UHPC denotes ultra-high performance concrete. The first two types consist of an OSD and a thin UHPC layer while the third type consists of a steel beam and a UHPC waffle deck. Due to excellent mechanical behaviors and impressive durability of UHPC, the steel-UHPC composite girders have the advantages of light weight, high strength, low creep coefficient, low risk of cracking, and excellent durability, making them competitive alternatives for long-span bridges. To date, the proposed steel-UHPC composite girders have been applied to 14 real bridges in China. It is expected that the application of the new steel-UHPC composite girders on long-span bridges will have a promising future.展开更多
基金support for this study provided by National Natural Science Foundation of China(Grant Nos.51908504 and 52278227).
文摘The steel-concrete composite bridge system with twin girders,referred to as a steel plate composite girder bridge,is widely adopted for short-to medium-span highway bridges due to its ability to enable rapid prefabrication and construction in bridge engineering.Considering the structural design of steel plate composite girder bridges,which are wide but shallow in depth,their deck slabs are vulnerable to vertical impacts from vehicle loads.Structural performance may be negatively affected by excessive dynamic displacement of deck slabs.It is difficult to assess the dynamic response of the deck slabs by existing methods,since traditional specifications only use a global impact factor to describe the dynamic effect of moving vehicles on the bridge as a whole,regardless of the local dynamic effect on the deck slabs.Therefore,this study aims to assess the local dynamic effect of moving vehicles on the deck slabs of steel plate composite beam bridges using field tests and finite-element methods.A systematic approach was employed to analyze parameters influencing bridge-vehicle interaction.Additionally,an improved method was presented to calculate the local impact factor and parametric studies were discussed.The findings indicated that the local impact factor of deck slabs is significantly greater than the global impact factor.Road surface roughness is the most significant parameter affecting deck slab dynamic behavior.
基金The authors would like to thank the following funders for providing support to this research: the National Key Research and Development Program of China (No. 2018YFC0705400)the National Natural Science Foundation of China (Grant Nos. 51778223 and 51708200)the Major Program of Science and Technology of Hunan Province (No. 2017SK1010).
文摘Steel and steel-concrete composite girders are two types of girders commonly used for long-span bridges. However, practice has shown that the two types of girders have some drawbacks. For steel girders, the orthotropic steel deck (OSD) is vulnerable to fatigue cracking and the asphalt overlay is susceptible to damage such as rutting and pot holes. While for steel-concrete composite girders, the concrete deck is generally thick and heavy, and the deck is prone to cracking because of its low tensile strength and high creep. Thus, to improve the serviceability and durability of girders for long-span bridges, three new types of steel-UHPC lightweight composite bridge girders are proposed, where UHPC denotes ultra-high performance concrete. The first two types consist of an OSD and a thin UHPC layer while the third type consists of a steel beam and a UHPC waffle deck. Due to excellent mechanical behaviors and impressive durability of UHPC, the steel-UHPC composite girders have the advantages of light weight, high strength, low creep coefficient, low risk of cracking, and excellent durability, making them competitive alternatives for long-span bridges. To date, the proposed steel-UHPC composite girders have been applied to 14 real bridges in China. It is expected that the application of the new steel-UHPC composite girders on long-span bridges will have a promising future.
