In this paper,a research was conducted on the design technology of continuous beam-arch composite bridges.A brief introduction is given on the of continuous beam-arch composite bridges,its basic mechanical characteris...In this paper,a research was conducted on the design technology of continuous beam-arch composite bridges.A brief introduction is given on the of continuous beam-arch composite bridges,its basic mechanical characteristics is analyzed,and three aspects of design technology is studied,which are rise-span ratio,stiffness ratio,and bridge deck cracking.This article acts as a reference for relevant design units in China to improve the design of continuous beam-arch combination bridges.展开更多
Objective:To compare the clinical therapeutic effect of bridge combined internal fixation system and locking compression plate internal fixation in the treatment of displaced midshaft clavicle fractures by emphaticall...Objective:To compare the clinical therapeutic effect of bridge combined internal fixation system and locking compression plate internal fixation in the treatment of displaced midshaft clavicle fractures by emphatically observing fracture healing and shoulder joint function.Methods:Totally 44 elderly patients with Robinson type 2B displaced midshaft clavicle fractures were included from the Department of Orthopaedics,Shenyang Fourth People's Hospital during February 2016 and December 2018,including 23 males and 21 females,mean age(69.8±10.2)years old.The patients were divided into a bridge combined internal fixation system group(bridge group,n=22)and a locking compression plate internal fixation group(plate group,n=22)according to the internal fixation methods.The operation time,intraoperative blood loss,fracture healing time,and postoperative complications were recorded.At 12 months after surgery,the shoulder joint Constant-Murley score and DASH score were used to assess the recovery of joint function.The serum levels of bone turnover biochemical markers procollagen I N-terminal peptide(P1NP),cross-linked Carboxy-terminal telopeptide of typeⅠcollagen(CTX-I),and osteoblast specific factor(OSF)were measured before and 3 months after surgery.Results:The operation time,intraoperative blood loss and fracture healing time of the bridge group were significantly shorter than those of the plate group(P<0.05).Constant scores and DASH scores in the bridge group were significantly better than those of the plate group at 12 months after surgery(P<0.05).Serum levels of CTX-I was significantly decreased,while the P1NP and OSF were significantly increased compared with before surgery in the both groups(P<0.05),and the changes were more obvious in the bridge group(P<0.05).The incidence of complications was similar between the two groups(P<0.05).Conclusion:Compared with the locking plate system,the bridge combined internal fixation system can effectively improve the operation efficiency,have more benefits on fracture healing,better promote the recovery of patients'function,and reduce the failure rate of internal fixation,thus providing a better choice to treat displaced midshaft clavicle fractures by intraoperative internal fixation.展开更多
Starting from the ideas of Conventional Post Tensioning we present a heuristic argument of advantages of combined actions of post compression along with post tensioned technique for a PSC member through a Design Examp...Starting from the ideas of Conventional Post Tensioning we present a heuristic argument of advantages of combined actions of post compression along with post tensioned technique for a PSC member through a Design Example. Our aim was to assess the characterization of a pre stressed member if it was?to be under the Load effects of post compressing a bar with post tensioned method through hydraulic jacks as the reinforcements in the tensioned zone of conventional PSC bridge were to be compressed in order to induce internal tensile stress similar to internal compressive stresses developed due to conventional post tensioned design. The results ultimately concluded that post compressing a Slender bar by a pre stressing force in the compression zone by a value equal to 0.1?-?0.7 times the pre stressing force in the tension zone would eventually lead to cancelling out of tensile and compressive stresses, thereby forming the desired section which is comparatively smaller in size but can account for sustainability. The anchorage at the top end was?provided by special slender steel rods to eliminate the compressive stresses. All the dead loads?were?counteracted by the action of prestress and the bridge section was able to carry only live load which is deduced through examples in the article.展开更多
Segmental bridges with unbonded prestressed tendons have some advantages, such as the weather independence and the corrosion protection of prestressing tendons. This paper analyzed the behavior of a prestressed segmen...Segmental bridges with unbonded prestressed tendons have some advantages, such as the weather independence and the corrosion protection of prestressing tendons. This paper analyzed the behavior of a prestressed segmental bridge with unbonded tendons under combined loading of torsion, bending and shear. According to the experiment research, a modified skew bending model was developed to calculate the bearing capacity of segmental bridges subjected to combined bending, shear and torsion. The finite element method was used to investigate the deflection behaviors of such structure, also to check the theoretical model. The theoretical and FEM research results were compared favorably with the test results from Technical University of Braunschweig, Germany. Finally, suggestion for the design and construction of segmental bridges with external prestressing was made.展开更多
It's a necessary selection to support the maneuver across Yangtze River by floating bridge constructed by portable steel bridge and civilian ships.It is a comprehensive index for the scheme of bridge raft,containi...It's a necessary selection to support the maneuver across Yangtze River by floating bridge constructed by portable steel bridge and civilian ships.It is a comprehensive index for the scheme of bridge raft,containing a variety of technical factors and uncertainties.The optimization is the selection in the constructing time,quantity of equipments and man power.Based on the calculation result of bridge rafts,an evaluating system is established,consisting of index of spacing between interior bays,raft length,truss numbers,operation difficulty and maximal bending stress.A fuzzy matter element model of optimizing selection of bridge rafts was built up by combining quantitative analysis with qualitative analysis.The method of combination weighting was used to calculate the value of weights index to reduce the subjective randomness.The sequence of schemes and the optimization result were gained finally based on euclid approach degree.The application result shows that it is simple and practical.展开更多
Zhongshan Bridge is a kind of steel arch bridge with a particular space-combined structure. The rationality of design, accuracy of theoretical calculation and reliability of transportation were studied. Its design, FE...Zhongshan Bridge is a kind of steel arch bridge with a particular space-combined structure. The rationality of design, accuracy of theoretical calculation and reliability of transportation were studied. Its design, FEM calculation of stresses and strains, and model test were introduced in detail. The theoretical analysis and model test verified that the design was reliable and safe. The simulated stresses, rigidity and stability, which are based on the selected loading system and cross-section geometry, satisfy the related design standards. Some of the issues that need to be considered in the real bridge construction were also discussed.展开更多
文摘In this paper,a research was conducted on the design technology of continuous beam-arch composite bridges.A brief introduction is given on the of continuous beam-arch composite bridges,its basic mechanical characteristics is analyzed,and three aspects of design technology is studied,which are rise-span ratio,stiffness ratio,and bridge deck cracking.This article acts as a reference for relevant design units in China to improve the design of continuous beam-arch combination bridges.
文摘Objective:To compare the clinical therapeutic effect of bridge combined internal fixation system and locking compression plate internal fixation in the treatment of displaced midshaft clavicle fractures by emphatically observing fracture healing and shoulder joint function.Methods:Totally 44 elderly patients with Robinson type 2B displaced midshaft clavicle fractures were included from the Department of Orthopaedics,Shenyang Fourth People's Hospital during February 2016 and December 2018,including 23 males and 21 females,mean age(69.8±10.2)years old.The patients were divided into a bridge combined internal fixation system group(bridge group,n=22)and a locking compression plate internal fixation group(plate group,n=22)according to the internal fixation methods.The operation time,intraoperative blood loss,fracture healing time,and postoperative complications were recorded.At 12 months after surgery,the shoulder joint Constant-Murley score and DASH score were used to assess the recovery of joint function.The serum levels of bone turnover biochemical markers procollagen I N-terminal peptide(P1NP),cross-linked Carboxy-terminal telopeptide of typeⅠcollagen(CTX-I),and osteoblast specific factor(OSF)were measured before and 3 months after surgery.Results:The operation time,intraoperative blood loss and fracture healing time of the bridge group were significantly shorter than those of the plate group(P<0.05).Constant scores and DASH scores in the bridge group were significantly better than those of the plate group at 12 months after surgery(P<0.05).Serum levels of CTX-I was significantly decreased,while the P1NP and OSF were significantly increased compared with before surgery in the both groups(P<0.05),and the changes were more obvious in the bridge group(P<0.05).The incidence of complications was similar between the two groups(P<0.05).Conclusion:Compared with the locking plate system,the bridge combined internal fixation system can effectively improve the operation efficiency,have more benefits on fracture healing,better promote the recovery of patients'function,and reduce the failure rate of internal fixation,thus providing a better choice to treat displaced midshaft clavicle fractures by intraoperative internal fixation.
文摘Starting from the ideas of Conventional Post Tensioning we present a heuristic argument of advantages of combined actions of post compression along with post tensioned technique for a PSC member through a Design Example. Our aim was to assess the characterization of a pre stressed member if it was?to be under the Load effects of post compressing a bar with post tensioned method through hydraulic jacks as the reinforcements in the tensioned zone of conventional PSC bridge were to be compressed in order to induce internal tensile stress similar to internal compressive stresses developed due to conventional post tensioned design. The results ultimately concluded that post compressing a Slender bar by a pre stressing force in the compression zone by a value equal to 0.1?-?0.7 times the pre stressing force in the tension zone would eventually lead to cancelling out of tensile and compressive stresses, thereby forming the desired section which is comparatively smaller in size but can account for sustainability. The anchorage at the top end was?provided by special slender steel rods to eliminate the compressive stresses. All the dead loads?were?counteracted by the action of prestress and the bridge section was able to carry only live load which is deduced through examples in the article.
文摘Segmental bridges with unbonded prestressed tendons have some advantages, such as the weather independence and the corrosion protection of prestressing tendons. This paper analyzed the behavior of a prestressed segmental bridge with unbonded tendons under combined loading of torsion, bending and shear. According to the experiment research, a modified skew bending model was developed to calculate the bearing capacity of segmental bridges subjected to combined bending, shear and torsion. The finite element method was used to investigate the deflection behaviors of such structure, also to check the theoretical model. The theoretical and FEM research results were compared favorably with the test results from Technical University of Braunschweig, Germany. Finally, suggestion for the design and construction of segmental bridges with external prestressing was made.
文摘It's a necessary selection to support the maneuver across Yangtze River by floating bridge constructed by portable steel bridge and civilian ships.It is a comprehensive index for the scheme of bridge raft,containing a variety of technical factors and uncertainties.The optimization is the selection in the constructing time,quantity of equipments and man power.Based on the calculation result of bridge rafts,an evaluating system is established,consisting of index of spacing between interior bays,raft length,truss numbers,operation difficulty and maximal bending stress.A fuzzy matter element model of optimizing selection of bridge rafts was built up by combining quantitative analysis with qualitative analysis.The method of combination weighting was used to calculate the value of weights index to reduce the subjective randomness.The sequence of schemes and the optimization result were gained finally based on euclid approach degree.The application result shows that it is simple and practical.
文摘Zhongshan Bridge is a kind of steel arch bridge with a particular space-combined structure. The rationality of design, accuracy of theoretical calculation and reliability of transportation were studied. Its design, FEM calculation of stresses and strains, and model test were introduced in detail. The theoretical analysis and model test verified that the design was reliable and safe. The simulated stresses, rigidity and stability, which are based on the selected loading system and cross-section geometry, satisfy the related design standards. Some of the issues that need to be considered in the real bridge construction were also discussed.
