Comparative assessment of finite-element and strut and tie based design methods for deep beams

This paper considers the design and analysis of a series of one and two-span deep beams that have been tested previously. The beams are assessed with non-linear finite-element analysis and two alternative strut and tie models. The reinforcement is subsequently designed to resist between 60 and 80% of the measured failure loads using a semi-automated finite-element based procedure and the two strut and tie models. The semi-automated design procedure is implemented in NonOpt, which is a Fortran program that works in conjunction with the finite-element program Diana. The reinforcement is designed to resist stresses calculated in a non-linear finite-element analysis. The case studies with NonOpt examine the influence of basing the initial reinforcement design on either a linear or non-linear finite-element analysis. The influence of tension stiffening is also considered. The least reinforcement weight is obtained when the initial design is based on a non-linear analysis without tension stiffening.