In this paper, an FEM （Finite Element Method） model is established for the main span of the bridge, with the main box arch and suspender members modeled by beam elements, truss members by truss elements, and the ort...In this paper, an FEM （Finite Element Method） model is established for the main span of the bridge, with the main box arch and suspender members modeled by beam elements, truss members by truss elements, and the orthotropic steel deck by plate elements. The natural frequencies and mode shapes are acquired by the eigen-parameter analysis. By input of a typical earthquake excitation to the bridge system, the dynamic responses of the bridge, including the displacement and accelerations of the main joints of the structure, and the seismic forces and stresses of the key members, are calculated by the structural analysis program, based on which the main laws of the seismic responses of the bridge are summarized, and the safety of the structure is evaluated.展开更多
Objective： To present our experience in treatment of difficult ununited long bone fractures with locking plate. Methods： Retrospective evaluation of locking plate fixation in 10 difficult nonunions of long bone fra...Objective： To present our experience in treatment of difficult ununited long bone fractures with locking plate. Methods： Retrospective evaluation of locking plate fixation in 10 difficult nonunions of long bone fractures was done. Fixation was done with locking plate for femoral shaft fracture （3 patients）, supracondylar fracture of femur （gap nonunion）, fracture of clavicle, fracture of both forearm bones （radius and ulna） fracture of ulna, fracture of shaft of humerus, fracture of tibial diaphysis and supracondylar frac- ture of humerus （one patient each）. Five fractures had more than one previous failed internal fixation. One patient had infected nonunion which was managed by debridement with cast immobilization followed by fixation with locking plate at six weeks. Seven fractures were atrophic, two were oligotrophic, and one was hypertrophic. Fibular autograft was used in 2 cases and iliac crest cancellous bone graft used in all the patients. Results： Minimum follow-up was 6 months （range, 6 months to 2.5 years）. Average time for union was 3.4 months （range 2.5 to 6 months）. None of the patients had plate- related complications or postoperative wound infections. Conclusion： Along with achieving stability with locking compression plate, meticulous soft tissue dissection, acceptable reduction, good fixation technique and bone grafting can help achieve union in difficult nonunion cases. Though locking plate does not by itself ensure bony union, we have found it to be another useful addition to our armamentarium for treating difficult fracture nonunions.展开更多
基金Acknowledgments： This study is sponsored by the Natural Science Foundation of China （No. 90715008） and the Flander （Belgium）-China Bilateral Project （No. BIL07/07）.
文摘In this paper, an FEM （Finite Element Method） model is established for the main span of the bridge, with the main box arch and suspender members modeled by beam elements, truss members by truss elements, and the orthotropic steel deck by plate elements. The natural frequencies and mode shapes are acquired by the eigen-parameter analysis. By input of a typical earthquake excitation to the bridge system, the dynamic responses of the bridge, including the displacement and accelerations of the main joints of the structure, and the seismic forces and stresses of the key members, are calculated by the structural analysis program, based on which the main laws of the seismic responses of the bridge are summarized, and the safety of the structure is evaluated.
文摘Objective： To present our experience in treatment of difficult ununited long bone fractures with locking plate. Methods： Retrospective evaluation of locking plate fixation in 10 difficult nonunions of long bone fractures was done. Fixation was done with locking plate for femoral shaft fracture （3 patients）, supracondylar fracture of femur （gap nonunion）, fracture of clavicle, fracture of both forearm bones （radius and ulna） fracture of ulna, fracture of shaft of humerus, fracture of tibial diaphysis and supracondylar frac- ture of humerus （one patient each）. Five fractures had more than one previous failed internal fixation. One patient had infected nonunion which was managed by debridement with cast immobilization followed by fixation with locking plate at six weeks. Seven fractures were atrophic, two were oligotrophic, and one was hypertrophic. Fibular autograft was used in 2 cases and iliac crest cancellous bone graft used in all the patients. Results： Minimum follow-up was 6 months （range, 6 months to 2.5 years）. Average time for union was 3.4 months （range 2.5 to 6 months）. None of the patients had plate- related complications or postoperative wound infections. Conclusion： Along with achieving stability with locking compression plate, meticulous soft tissue dissection, acceptable reduction, good fixation technique and bone grafting can help achieve union in difficult nonunion cases. Though locking plate does not by itself ensure bony union, we have found it to be another useful addition to our armamentarium for treating difficult fracture nonunions.
