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An investigation of the seismic behaviour and a design method for single-layer reticulated shells with semi-rigid joints is described in this paper. A semi-rigid joint system has some bending and rotational rigidity that lying between that of a rigid-joint and a pin-joint. The seismic capacity of Kiewit reticulated shells with bolt-ball joints is analyzed in detail on the basis of the bending rigidity of the bolt-ball joint reported by others. The change rules of natural frequency and seismic internal force coefficient are reviewed by analyzing of large-scale shells with different span, depth-to-span ratio, bending rigidity, roof load, section size of members and seismic wave parameters. The seismic internal force coefficient (under the influence of bending moment) for shells with a semi-rigid joint system is summarized statistically to provide the maximal seismic response envelop. [ABSTRACT FROM AUTHOR]

Abstract: Socket joint systems are typical semi-rigid joints used in space structures. This paper presents numerical analyses of semi-rigid joint systems in which the bolts are pretensioned. Eleven numerical models of socket joints are studied: three of them are subjected to bending and the others are subjected to proportional bending and axial compression. Moment–rotation relationships of the joints are obtained using models in which the material and geometric nonlinearity are taken into account. The load-carrying mechanism of socket joint system is investigated in detail through the numerical analysis. Through comparison of the finite element analysis (FEA) and corresponding test measurements, it is shown that the proposed FEA models can be used effectively to describe the mechanical performance of the semi-rigid joints in spatial structures, including the initial bending stiffness, ultimate bending moment, deformation and the failure mode. [Copyright &y& Elsevier]

Abstract: Socket joints and bolt-ball joints are typical semi-rigid joint systems widely used in spatial structures. In this paper, tests on fifteen joints are carried out to study their mechanical behavior. Three socket joint systems are subjected to bending moment and shear force, and another seven socket joint systems and five bolt-ball joint systems are subjected to bending moment, shear force and axial compressive force. The main characteristics of the moment–rotation relationship for the connections under different loading schemes are summarized and discussed. The results indicate that: (i) both socket and bolt-ball joint systems have good bending stiffness; (ii) the axial compressive force increases the initial bending stiffness of the joints; (iii) the axial compressive force has different effects on the bending moment capacity of different joints; and (iv) the yield process of moment–rotation curves of the joints is shortened due to the action of the axial compressive force. [Copyright &y& Elsevier]

Abstract: A new classification system for the joints in lattice shells is proposed. The stiffness and moment capacity of the joints together with the overall structural behavior of the lattice shells are considered in order to establish the classification system. According to this new system, joints in lattice shells can be classified into unique categories: rigid, semi-rigid or pinned. The rigid joints have both high bending stiffness and moment capacity; the semi-rigid joints have both moderate bending stiffness and moment capacity, and the pinned joints have either low bending stiffness or low moment capacity. Determination coefficients α and β are defined, based on the stiffness and moment capacity of the joints, and these are used to establish clear boundaries between the different categories. Some numerical examples are included to demonstrate the validity of the classification system. With the help of the classification system, an efficient process for practical engineering design is proposed, which can help designers choose the appropriate analysis method for lattice shells with different joints. [Copyright &y& Elsevier]