Cost minimization for safety enhancing of timber beam structures in historical buildings

A search method for finding rational parameters of beam structure bearing capacity recovery systems has been developed. This task is relevant to historic buildings containing girders with structural damage. The solution search technique is implemented by the example of calculating the parameters for timber beams external bearing capacity restoration systems with local damage or destruction of supports. An adapted genetic algorithm is used as a tool to solving the problem. A feature of this algorithm is the use of an improved random change operator and the formation of an initial and subsequent solutions sets. In this case, classical evolutionary modelling operators are not used, and the preservation of solutions from iteration to iteration is performed based on modification of the well-known elitism principle. Such computational process has allowed increasing the convergence of the iterative optimization significantly for the tasks considered. Ensuring the structure safety is achieved by strength conditions and regulating the system deflection while minimizing the costs for its operation. Herewith, the objective function allows taking into account both the lump-sum costs for system restoration arrangement and the costs for maintaining its operation during the operation cycle. An example of restoring the beam bearing capacity with the loss of stiffness of its supporting and middle span sections has been considered.