Wine Figeys

Strengthening of Concrete Structures using Steel Wire Reinforced Polymer

SYNOPSIS: This paper deals with a new material for external reinforcement: Steel Wire Reinforced Polymer (SWRP). It consists of thin high-strength steel fibres embedded in a polymer laminate. This innovative material combines the advantages of steel plates and CFRP, which are already used today. The material cost of SWRP is relatively low, and the laminate is quite flexible. In the feasibility part, the practical use of SWRP is studied. Further, the available design model for externally bonded reinforcement for concrete elements is confronted with the results of an experimental program, carried out at the Reyntjens Laboratory of KULeuven. The model is adapted accordingly.

Strengthening of an industrial cylindrical shell damaged by a collision

This case-study concerns an old industrial reinforced concrete shell structure at the port of Antwerp. The building serves as a pilot for stowing of shipped steel and wooden products. A fork-lift hit one of the supporting columns. The impact of the collision caused the concrete to crush and the internal reinforcement to shift considerably. Some of the internal reinforcement yielded or broke. Temporary supports had to be placed to avoid collapse of the total structure. The stress situation is analyzed. A FEM model was built to gain insight into the stress distribution in the shell structure. In comparison with the undamaged situation, membrane forces, shear forces and moments did strongly increase which explains the actual damage. A solution is worked out to repair and strengthen the damaged part of the structure. The FEM-analysis demonstrates that a compression arch will arise in the top of the barrel shell to span the displaced support. This requires a tension member at the bottom side of the concrete barrel. Therefore, externally bonded reinforcement is applied to increase the tensile capacity of the perimeter beam. The web reinforcement has yielded or is broken so that it is replaced by external CFRP reinforcement. After strengthening the structure, a monitoring system is installed. Strain gauges are glued on several laminates. These measurements give feed back on the structural behaviour of the strengthened structure and the applicability of the FEM used. This case-study illustrates the load distribution mechanisms in the shell structure, the assessment of the actual condition and an appropriate intervention based on external reinforcement.

New Trends in Rehabilitation and Consolidation of Historical Concrete and Masonry Constructions / Neue Wege beim Instandsetzen und Festigen historischer Gebäude aus Beton und Mauerwerk

New trends in structural consolidation and strengthening techniques are based on the true nature and stress-strain behaviour of the concrete and masonry material, as well as on the understanding of the load distribution and deformation mechanisms acting in such structures. Safety, reliability and risk are key issues in rehabilitation as well as in the preservation of the built, cultural environment. Powerful methods are becoming available for the calculation of structural safety values, and they allow to calculate the global probability of failure of complex structures. These methods need appropriate analysis models as input, as well as reliable design models for strengthening of structural elements by means of externally bonded steel plates or fibre reinforced laminates, or design models for the effect of grouting on strength and stiffness of ancient brick or block masonry. Such models are derived from research, which combines investigation and development of new materials, non-destructive testing, laboratory and site investigation. This global approach, as it is practiced in the Reyntjens Laboratory of K.U.Leuven, and applied in rehabilitation and restoration projects by Triconsult n.v., is presented and documented with case-studies.