Dominik Kueres

Strengthening of Existing Bridge Structures for Shear and Bending with Carbon Textile-Reinforced Mortar

Increasing traffic loads and changes in code provisions lead to deficits in shear and flexural capacity of many existing highway bridges. Therefore, a large number of structures are expected to require refurbishment and strengthening in the future. This projection is based on the current condition of many older road bridges. Different strengthening methods for bridges exist to extend their service life, all having specific advantages and disadvantages. By applying a thin layer of carbon textile-reinforced mortar (CTRM) to bridge deck slabs and the webs of pre-stressed concrete bridges, the fatigue and ultimate strength of these members can be increased significantly. The CTRM layer is a combination of a corrosion resistant carbon fiber reinforced polymer (CFRP) fabric and an efficient mortar. In this paper, the strengthening method and the experimental results obtained at RWTH Aachen University are presented.

Improvement of Punching Shear Design Provisions According to Eurocode 2

The punching shear design of flat slabs and footings was revised with the introduction of Eurocode 2. While in many former codes the punching shear resistance was determined regardless of the type of member, in Eurocode 2 two different design equations for flat slabs and footings were introduced. Additionally, different control sections for flat slabs and footings were defined. The differentiation between flat slabs and footings and especially the iterative design procedure for the determination of the punching shear resistance of footings require great effort in daily engineering practice.

Experimental Investigations on the Shear Capacity of Prestressed Concrete Continuous Beams with Rectangular and I-Shaped Cross-Sections

Due to increased traffic loads and changes in the code provisions many bridges in Germany exhibit shear capacity deficits according to current codes. However, the shear capacity of prestressed concrete continuous beams might be underestimated according to recent test results. Also, the design procedures have usually been verified on the basis of single span beam tests so that additional tests on continuous beams seem appropriate. In order to extent the service life of existing bridges, the epistemic safety margins in the design procedures can in part be used by application of refined design approaches. For this reason, five shear tests on prestressed concrete continuous beams are performed at the Institute of Structural Concrete of RWTH Aachen University (Germany). Within these tests, the influence of the cross-section type (rectangular and I-shaped cross-section), the load distribution (concentrated and distributed loads) and the shear reinforcement ratio is investigated. In this paper, the preliminary test results of two beams under concentrated loads will be presented.