BACKGROUND Radiocarpal dislocations are rare but potentially devastating injuries.Poorer outcomes are associated with inadequate or lost reduction,such as ulnar translocation,but no consensus exists on the ideal fixat...BACKGROUND Radiocarpal dislocations are rare but potentially devastating injuries.Poorer outcomes are associated with inadequate or lost reduction,such as ulnar translocation,but no consensus exists on the ideal fixation technique.Dorsal bridge plate fixation has been described for various settings in the treatment of complex distal radius fractures and can be fixed distally to the second or third metacarpal,but its application for radiocarpal dislocations has not been established.AIM To determine whether distal fixation to the second or third metacarpal matters.METHODS Using a cadaveric radiocarpal dislocation model,the effect of distal fixation was studied in two stages:(1)A pilot study that investigated the effect of distal fixation alone;and(2)a more refined study that investigated the effect of described techniques for distal and proximal fixation.Radiographs were measured in various parameters to determine the quality of the reduction achieved.RESULTS The pilot study found that focusing on distal fixation alone without changing proximal fixation results in ulnar translocation and volar subluxation when fixing distally to the second metacarpal compared with the third.The second iteration demonstrated that anatomic alignment in coronal and sagittal planes could be achieved with each technique.CONCLUSION In a cadaveric radiocarpal dislocation model,anatomic alignment can be maintained with bridge plate fixation to the second metacarpal or the third metacarpal if the described technique is followed.When considering dorsal bridge plate fixation for radiocarpal dislocations,the surgeon is encouraged to understand the nuances of different fixation techniques and how implant design features may influence proximal placement.展开更多
This paper reports the results of experimental research the longitudinal stiffeners in an orthotropic plated bridge deck on concerning the connection between the deck plate and the web of a microscopic scale. An impor...This paper reports the results of experimental research the longitudinal stiffeners in an orthotropic plated bridge deck on concerning the connection between the deck plate and the web of a microscopic scale. An important number of test specimens of a weld are studied with the help of a video microscope, to detect the efficiency of the root of the weld. The second part of the paper is concerned with parametric analysis of the lack of weld penetration by using accurate finite element modelling. The results demonstrate that the weld quality often required can not always be assured, which surely has important consequence on the stresses in the weld and the fatigue resistance.展开更多
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
文摘BACKGROUND Radiocarpal dislocations are rare but potentially devastating injuries.Poorer outcomes are associated with inadequate or lost reduction,such as ulnar translocation,but no consensus exists on the ideal fixation technique.Dorsal bridge plate fixation has been described for various settings in the treatment of complex distal radius fractures and can be fixed distally to the second or third metacarpal,but its application for radiocarpal dislocations has not been established.AIM To determine whether distal fixation to the second or third metacarpal matters.METHODS Using a cadaveric radiocarpal dislocation model,the effect of distal fixation was studied in two stages:(1)A pilot study that investigated the effect of distal fixation alone;and(2)a more refined study that investigated the effect of described techniques for distal and proximal fixation.Radiographs were measured in various parameters to determine the quality of the reduction achieved.RESULTS The pilot study found that focusing on distal fixation alone without changing proximal fixation results in ulnar translocation and volar subluxation when fixing distally to the second metacarpal compared with the third.The second iteration demonstrated that anatomic alignment in coronal and sagittal planes could be achieved with each technique.CONCLUSION In a cadaveric radiocarpal dislocation model,anatomic alignment can be maintained with bridge plate fixation to the second metacarpal or the third metacarpal if the described technique is followed.When considering dorsal bridge plate fixation for radiocarpal dislocations,the surgeon is encouraged to understand the nuances of different fixation techniques and how implant design features may influence proximal placement.
文摘This paper reports the results of experimental research the longitudinal stiffeners in an orthotropic plated bridge deck on concerning the connection between the deck plate and the web of a microscopic scale. An important number of test specimens of a weld are studied with the help of a video microscope, to detect the efficiency of the root of the weld. The second part of the paper is concerned with parametric analysis of the lack of weld penetration by using accurate finite element modelling. The results demonstrate that the weld quality often required can not always be assured, which surely has important consequence on the stresses in the weld and the fatigue resistance.
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.
