On the numerical assessment of the separation zones in semirigid column base plate connections

The present paper concerns the mathematical study and the numerical treatment of the problem of semirigid connections in bolted steel column base plates by taking into account the possibility of appearance of separation phenomena on the contact surface under certain loading conditions. In order to obtain a convenient discrete form to simulate the structural behaviour of a steel column base plate, the continuous contact problem. By applying an appropriate finite element scheme, the discrete problem is formulated as a quadratic opimization problem which expresses, from the standponint of mechanics, the principle of minimum potential energy of the semirigid connection at eh state of equilibrium. For the numerical treatment of this problem, two effective and easy-to-use solution strategies based on quadratic optimization algorithms are proposed. This technique is illustrated by means of a numerical application.