Study On Form Finding And Form Optimization Of Pretensioned Cable Roofs

In order to meet the needs of the practical structural design, the new approach for the form finding of cable roofs is proposed in this paper. It is called as the modified force density method. The method is verified by some benchmark problems and big projects. Numerical examples show that the modified method is very simple and efficient. It can be used to find the shape of various pretensioned cable roofs.In this paper, modified dynamic relaxation method and modified force density method for form finding of pretensioned cable roofs are comprehensively compared and analyzed in the aspects of calculation time, convergence precision and iterative tactics by some benchmark problems and big projects. The analysis indicates that the two methods can be applied to the form finding of complex and large cable nets, both of them are precise, but each one has its advantages and shortcomings.Based on the characteristics of the form optimization of cable nets, such as multiple design parameters, multiple object functions, genetic algorithms are suggested to solve the above questions in the paper. By using weighted coefficients, the multiple object functions are turned into single object function. The individual that disobey restrict conditions is punished with Gen and Cheng method. Examples show that the genetic algorithm is feasible and convergent in form optimization of the pretensioned cable roofs, and it has many merits, such as strong holistic searching capability, good operation steadiness.