Systematic correction of stiffness of a finite element model by means of measured eigenvalues and derivation of concrete identification factors of a dowel connection

The correct dynamic behaviour of a real structure can be described by an analytical finite element model only when the parameters of the finite element model are correctly assumed. The dynamic prediction is closely related to the choice of the boundary stiffness, the intermediate elements and the geometric properties of open-cross-section beams.First, laboratory tests are carried out on a test set-up which consists of a piping support, anchorage elements and a concrete block. The test parameters include the variation of dowel tightening torque, the anchor plate stiffness and the concrete block. The first comparison of analytical and test results did not show good agreement. The uncertain stiffness of the finite element model is systematically adjusted by means of indirect parameter identification with measured eigenvalues. A high degree of agreement is obtained between the analytical and measured eigenvalues at the end of the iterative procedure. The required concrete stiffnesses are derived from a spring model which includes all important stiffness terms of a dowel connection. The typical concrete identifications are derived from the affected pressure concrete cones. For similar dowel connections the equivalent concrete stiffness can be analytically determined using the derived identification factors.