Considerations in Design of Joints for Lattice Steel Cooling Towers of Power Plants

Understanding the ultimate and the working strength and stiffness of the connections is required for the design of spatial structures. Comparison of numerical modeling with the experimental results is the most useful method to investigate the structural behaviour of the joints. The geometry and proportions of a particular connection depend on various factors such as the magnitude of forces, the size of the structural members, the end-details of the elements, the method of construction and economic factors. This paper studies the structural behaviour of the joints of a steel lattice cooling tower. A good number research on spatial structures is devoted to obtain the strength and stiffness of the nodes and/or assembly of nodes and structural members. For instance, Maalek (1999) presents the results of experimental and numerical works on Akam socket joints. In this work, Akam spherical socket nodes of diameter 250 mm of ST37 and ST52 are subjected to various biaxial combinations of tensile and compressive forces. Chenaghlou et. al. (2014) study the behaviour of a type of ball joint and propose a model for obtaining its rotational rigidity and strength under various loading conditions. Davoodi et. al. (2012), study the nonlinear behaviour of a ball joint used in spatial structures. Ahmadizadeh and Maalek (2014), investigate the effect of the flexibility of the socket joints in spatial structures.