The design of semi-integral bridges is a challenging task for planning engineers. Most components of semi-integral bridges are connected monolithically, and many parameters influence their structural behavior. This paper deals with the piers of semi-integral bridges and their monolithic connection to the superstructure. Simple design rules for conventional bridges, such as "more reinforcement, more safety" are not valid for such interactive structures. In a monolithic connection no free deformation is permitted, and constraint forces and moments occur as a result. The magnitude of the constraint forces and moments primarily depends on the stiffness of the structure, which is influenced by several parameters. In this paper, two parameters are investigated: the normal force, which influences the cracking state of the cross section and the reinforcement ratio.
The goal of this paper is the determination of simple design criteria for the preliminary design of the piers of semi-integral bridges.