Vertical seismic performance is an important issue for the seismic design of large-scale engineering structures. The structure, which is relatively flexible and unrestricted vertically, may resonate and its response is obviously magnified under vertical earthquake excitations. The main objective of this study is to investigate the earthquake-resistance performance of a quayside container crane under vertical seismic excitations. To this end, a geometric-scaled model of 1:50 was firstly constructed according to the similitude law. Then using this model, a hammering modal test and a series of shaking table tests were successively conducted to obtain the dynamic characteristics and vertical seismic responses. Furthermore, the experimental results were compared with the computed results of prototype obtained from numerical analysis and agreed fairly well. From dynamic response results, it is found that the large-scale structure has relatively high vertical earthquake-resistance capacity and could satisfy the seismic design requirement. The findings reported in this paper are expected to provide some valuable information for studying other similar structures in the future.
FASTMast (Folding Articulated Square Truss Mast) deployable structure is the main bracing structure for the flexible solar array of the international space stations. This study investigates the buckling of FASTMast deployable structures. To this end, the buckling modes and the stiffness characteristics of this structure using the flex batten as an elastic bearing member were theoretically analyzed. The analytical results show that (1) the buckling mode of a FASTMast deployable structure is similar to the elbow joint movement failure when the stiffness of the flex batten is below a critical stiffness value. Once this critical stiffness is reached, the buckling mode takes on the form of Euler buckling. (2) The stiffness of the flex batten is proportional to its cross-sectional second moment of area. Furthermore, an experimental study was carried out to validate the accuracy of the theoretical analysis. The results from experimental work agree fairly well with those from theoretical analysis. The research findings herein are expected to be useful for future studies on similar structures.
Quayside container crane is a kind of huge dimension steel structure, which is the major equipment used for handling container at modern ports. With the aim to validate the safety and reliability of the crane under seismic loads, besides conventional analysis, elastic-plastic time history analysis under rare seismic intensity is carried out. An ideal finite element (FEM) elastic-plastic mechanical model of the quayside container crane is presented by using ANSYS codes. Furthermore, according to elastic-plastic time history analysis theory, deformation, stress and damage pattern of the structure under rare seismic intensity are investigated. Based on the above analysis, the established reliability model according to the reliability theory, together with seismic reliability analysis based on Monte-Carlo simulation is applied to practical analysis. The results show that the overall structure of the quayside container crane is generally unstable under rare seismic intensity, and the structure needs to be reinforced.
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