• Smart Structures and Systems
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• 제10권6호
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• pp.557-572
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• 2012

This paper focuses on the vibration control of long-span reticulated steel structures under multi-dimensional earthquake excitation. The control system and strategy are constructed based on Magneto-Rheological (MR) dampers. The LQR and Hrovat controlling algorithm is adopted to determine optimal MR damping force, while the modified Bingham model (MBM) and inverse neural network (INN) is proposed to solve the real-time controlling current. Three typical long-span reticulated structural systems are detailedly analyzed, including the double-layer cylindrical reticulated shell, single-layer spherical reticulated shell, and cable suspended arch-truss structure. Results show that the proposed control strategy can reduce the displacement and acceleration effectively for three typical structural systems. The displacement control effect under the earthquake excitation with different PGA is similar, while for the cable suspended arch-truss, the acceleration control effect increase distinctly with the earthquake excitation intensity. Moreover, for the cable suspended arch-truss, the strand stress variation can also be effectively reduced by the MR dampers, which is very important for this kind of structure to ensure that the cable would not be destroyed or relaxed.

• Steel and Composite Structures
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• 제18권2호
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• pp.481-496
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• 2015

A Lead Extrusion Damper (LED) is experimentally studied under various frequencies and displacement amplitudes. Experimental results show that the force-displacement hysteresis loops of the LED are close to rectangular and the force-velocity hysteresis loops exhibit nonlinear hysteretic characteristic. Also, the LED can provide consistent energy dissipation without any stiffness degradation. Based on the experimental results, a mathematical model is then proposed to describe the effects of frequency and displacement on property of LED. It can be proved from the comparison between experimental and numerical results that the mathematical model can accurately describe the mechanical behavior of LED. Subsequently, the seismic responses of the Schwedler reticulated shell structure with LEDs are analyzed by ANSYS software, in which three different installation forms of LEDs are considered. It can be concluded that the LED can effectively reduce the displacement and acceleration responses of this type of structures.

• Structural Engineering and Mechanics
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• 제56권4호
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• pp.667-694
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• 2015

The suspended dome system is a new structural form that has become popular in the construction of long-span roof structures. Suspended dome is a kind of new pre-stressed space grid structure that has complex mechanical characteristics. In this paper, an optimum topology design algorithm is performed using the enhanced colliding bodies optimization (ECBO) method. The length of the strut, the cable initial strain, the cross-sectional area of the cables and the cross-sectional size of steel elements are adopted as design variables and the minimum volume of each dome is taken as the objective function. The topology optimization on lamella dome is performed by considering the type of the joint connections to determine the optimum number of rings, the optimum number of joints in each ring, the optimum height of crown and tubular sections of these domes. A simple procedure is provided to determine the configuration of the dome. This procedure includes calculating the joint coordinates and steel elements and cables constructions. The design constraints are implemented according to the provision of LRFD-AISC (Load and Resistance Factor Design-American Institute of Steel Constitution). This paper explores the efficiency of lamella dome with pin-joint and rigid-joint connections and compares them to investigate the performance of these domes under wind (according to the ASCE 7-05), dead and snow loading conditions. Then, a suspended dome with pin-joint single-layer reticulated shell and a suspended dome with rigid-joint single-layer reticulated shell are discussed. Optimization is performed via ECBO algorithm to demonstrate the effectiveness and robustness of the ECBO in creating optimal design for suspended domes.

• Structural Engineering and Mechanics
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• 제54권1호
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• pp.121-133
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• 2015

The aluminum dome has been widely used in natatorium, oil storage tank, power plant, coal, as well as other industrial buildings and structures. However, few research has focused on the structural behavior and design method of this dome. At present, most designs of aluminum alloy domes have referred to theories and methods of steel spatial structures. However, aluminum domes and steel domes have many differences, such as elasticity moduli, roof structures, and joint rigidities, which make the design and analysis method of steel spatial structures not fully suitable for aluminum alloy dome structures. In this study, a stability analysis method, which can consider structural imperfection, member initial curvature, semi-rigid joint, and skin effect, was presented and used to study the stability behavior of aluminum dome structures. In addition, some meaningful conclusions were obtained, which could be used in future designs and analyses of aluminum domes.