Abstract:

Aiming at the tension forming of a spoke-shaped tensile cable-strut assembly,which is an important step of the assembly construction,an analytical parabolic element was adopted to simulate the cable based on the unstressed cable length and the structural topology,and a nodal unbalanced force vector was formulated with the equilibrium matrix of the pin-jointed cable-strut system. Then,on the basis of the finite-element nodal equilibrium
equation and by considering the continuous and compatible constrained linear displacement and the boundary constraints,the global stiffness matrix was described in a sector form,and a united nodal unbalanced force formula was thus deduced for the perimetric beam-column-cable joints,which only takes into consideration 3 linear degrees of freedom. Moreover,a nonlinear iterative resolution was performed via the dynamic relaxation for the deduced formula,and the proposed algorithm was implemented by programming. Finally,a case study on the tension forming of the tensile cable-strut canopy of Shenzhen Baoan Stadium was carried out with the proposed algorithm. The results indicate that ( 1) the proposed algorithm is effective in analyzing the tension forming; ( 2) the parabolic element is more accurate in cable simulation than the link element; and ( 3) the synergistic effects of perimetric column-beam structures cannot be neglected during the simulation of integral tension forming.

Key words: spoke-shaped tensile cable-strut assembly, tension forming, parabolic element, united nodal unbalanced force, dynamic relaxation