The goal of paper is the development and demonstration of efficiency of algorithm for form finding of a slack cable notwithstanding of the initial position chosen. This algorithm is based on product of two sets of coefficients, which restrict the rate of looking for cable geometry changes at each iteration. The first set restricts the maximum allowable change of absolute values of positions, angles and axial forces. The second set takes into account whether the process is the converging one (the signs of maximal change of parameters remain the same), so that it increases the allowable changes; or it is a diverging one, so that these changes are discarded. The proposed procedure is applied to two different methods of simple slack cable calculation under a number of concentrated forces. The first one is a typical finite element method, with the cable considered as consisting of number of straight elements, with unknown positions of their ends, and it is essentially an absolute coordinate method. The second method is a typical Irvine’s like analytical solution, which presents only two unknowns at the initial point of the cable; due to the peculiarity of implementation it is named here a shooting method. Convergence process is investigated for both solutions for arbitrary chosen, even very illogical initial positions for the ACM, and for angle and force at the left end for SM as well. Even if both methods provide the same correct convergent results, it is found that the ACM requires a much lower number of iterations.

The self-centering buckling-restrained brace (SC-BRB) may achieve self-restoration for structures and, to a certain degree, diminish the substantial seismic residual deformation following rare earthquakes when compared to the usage of the conventional buckling-restrained brace (BRB). It may be possible to reduce the abrupt change in stiffness at the location of the strengthened stories and make the outrigger better at dissipating energy by improving the design of the energy-dissipation outrigger. This study compares the seismic performances of two types of energy-dissipation outriggers with BRB and SC-BRB web member designs during rare earthquakes so that the changes can be measured. The results show that using the SC-BRB web member design reduces the maximum inter-story drift ratio by an average of 7.68% and increases the average plastic-energy dissipation of the outrigger truss by 8.75%. The evaluation results showthat the SC-BRB outrigger truss structure has better structural regularity and energy-dissipation performance. It has the ability to efficiently regulate the structural seismic response and lessen primary-structure damage.