The Mechanical Properties And The Optimization Design Of Prestressed Cable Reinforced Bearing Failure Of Double-layer Cylinder Reticulated Shell

With the wide application of reticulated shell in engineering, it’s found that the bearing failure of the double-layer orthogonal square pyramid cylindrical reticulated shell often happens because of the construction and so on. But it has large span and unidirectional force transmission which leads to the case that the bearing horizontal force is large and the support become key part. This paper presents theoretical analysis deeply on the reinforcement of bearing failure of this structure. The main contents are listed as follows:(1)Choosing the double-layer orthogonal square pyramid cylindrical reticulated shell in engineering as an analysis object, the static, dynamic and stable performance before and after bearing failure are analyzed with SAP2000. Compare the analysis results and the conclusion that bearing failure significantly reduces the overall stiffness of the structure and worses the static properties, vibration characteristics and instability mode is obtained.(2)Based on the analytical results of comparisons between the static,dynamic and stable performance of a prestressed cable reinforcing double-layer orthogonal square pyramid cylindrical reticulated shell structure under bearing failure and that of one before failure happens, the optimal method of reinforcement is determined as follows:to make reinforcement by increasing the stiffness of the whole structure and firstly propose the reinforcement technology of reinforcing the reticulated shell structure support by adding prestressed cable to supports.(3)Nonlinear analysis of the static, dynamic and stable performance on the bearing failure case of a prestressed cable reinforcing double-layer orthogonal square pyramid cylindrical reticulated shell structure is carried on. Besides,the nonlinear analytical results are compared with the ones before reinforcement was conducted,from which conclusion is drawn that prestressed cable can significantly increase the overall stiffness of the structure, improve the static properties, vibration characteristics and instability mode after failure and leads to a good reinforcing effect.(4)The optimization analysis of cable along the cross to different location, prestressed reinforcement of the cable and boundary conditions in the bearing failure case of a prestressed cable reinforcing double-layer orthogonal square pyramid cylindrical reticulated shell structure is carried on. Conclusion is drawn that when cable is fully prestressed at the support, the standard of prestress is that the vertical displacement of the vaule is0and the horizontal restraint at one end is released, the optimal reinforcement effect is obtained.(5)The principal geometric parameters of the rise-span ratio is selected and the geometric parameter of bearing failure of prestressed cable reinforcing double-layer orthogonal square pyramid cylindrical reticulated shell structure is analyzed.(6)Based on optimization results, the failure case of a double-layer orthogonal square pyramid cylindrical reticulated shell structure in the farming market of Nanfeng town in Zhang Jiagang is analyzed and the conclusion is drawn as follows:the peak stress ratio of reinforced structures are less than1, the peak displacements are significantly decreased which is less than1/400of the short span, and reinforced structures can meet safety requirements.