Numerical simulation and experimental testing of a new bridge strengthening method

Since bridges are constantly subjected to cyclic loading due to the high traffic load, deterioration in stiffness is often the result. A new strengthening method was developed and tested for its behaviour under fatigue. A thin bonded unreinforced overlay made of concrete for the upper region with exposed aggregate surface was added to the existing bridge deck to increase its load carrying capacity. As the overlay also serves as concrete carriageway, it reduces the weights on the bridge since no asphalt surface is needed anymore. In order to achieve a high efficiency of the fatigue testing facility, analytical and numerical analyses were carried out. Because of the stiffness, mass and damping features, the test specimen itself becomes the major element of the testing facility. In order to obtain values of the stiffness of the reinforced concrete, specimen calculations are made by using a finite element program, taking into account the nonlinear material behaviour and concrete cracking. With the previously determined stiffness, the resonance frequency was determined analytically and numerically by using the finite element method in a 3D-model.