Fatigue of Semi-precast Slabs with Lattice Girders

Fatigue of Semi-precast Slabs with Lattice Girders To investigate the fatigue behaviour of semi-precast slabs with lattice girders, theoretical and experimental investigations have been conducted at the Institute of Structural Concrete, RWTH Aachen University (IMB) within an AiF research project [1]. Besides small size specimens with diagonals of lattice girders casted in concrete to derive fatigue-strength-curves, fourteen semi-precast slabs specimens with lattice girders have been tested under cyclic loading. The investigated parameters were the roughness of shear joint, slab size, shear reinforcement ratio and concrete strength. To verify the fatigue design of semi-precast slabs with lattice girders, the test results have been evaluated and the stress ranges of the lattice girders have been compared to the calculated stress ranges according to AbZ and EC2+NA(D). The present paper presents the experimental investigations and compares the tests results to national design regulations.