A United Algorithm for Limit State Determination of Frames with Semi-Rigid Connections

A computer program is proposed to calculate the limit states of the frameworks with the following problems: Elastic analysis, Limit analysis, First-order and second-order elastic-plastic analysis, Shakedown analysis, Optimization-Limit, Optimization-Shakedown have been realised by Nguyen-Dang Hung in 1980, namely CEPAO. All of these calculations are connected with the problem of automatic search of independent mechanism in the sense of limit analysis. This permits to solve a lot of problems in a unified computer package with considerable reduction of memory and time consuming. The elastic and elastic-plastic analysis use equilibrium-stiffness method, while other above mentioned problems are solved by an internal linear programming algorithm. Concerning the stable design concept, the package finds the practical discrete profiles existing in the Eurocode and realises the stability checks. The present paper proposes an extension of this general software to the case of semi-rigid connections. New implementations are performed such that large dimension problems may be solved without difficulties. Some new numerical results for simple as well as large dimension frames are presented showing the performances of the program CEPAO compared to the recent literature.