Experimental Investigation of Arching Effects in Prestressed Concrete Beams with Parallel Chords

Abstract

The truss model as defined by DIN EN 1992-2/NA is largely based on the assessment of shear force experiments carried out on untensioned reinforced single-span concrete beams. Hence, this model does not take into sufficient account the specific structural behavior characteristics of large prestressed continuous concrete beams. Additionally, concrete beams provide a significant concrete contribution to the shear load bearing capacity due to arching effects, which is of particular interest at prestressed concrete beams. This compressive membrane action is not taken into account for bridge design according to DIN EN 1992-2 and the corresponding German National Annex.

As part of several research programs experimental investigations into the shear load bearing behavior of prestressed continuous concrete beams had been carried out at the Chair of Concrete Structures at TU Dortmund University. The overall target was to analyze the extremely favorable arching effects which are also of huge importance at prestressed concrete beams with parallel chords. Such arching effects provide significant relief from shear forces and could be measured, visualized and documented using suitable measurement technique.