Strengthening Load-Bearing Wall Openings Using Concrete Beams and CFRP: Case Study

Abstract

In building rehabilitation and strengthening works, the need to create openings in existing walls is usual. When those walls are load-bearing walls, the loading path is locally altered; therefore, it is required to strengthen the vicinity of the new opening. In this paper, two strengthening techniques widely applied to strengthen openings in existing walls are described. Those techniques are structurally different; the first technique makes use of reinforced concrete beams, and the second uses externally bonded carbon fiber–reinforced polymer (CFRP) strips. The concrete-beam technique can also be used to underpin structural elements when existing load-bearing walls are completely eliminated. Onsite observations have allowed the conclusion that good strengthening results can be obtained. Additionally, those construction practices are carried out with minimum disruption inside the building. The main parameters defining the strengthening technique choice are the length of the opening, the material, and the width of the existing wall. The loading values acting in existing walls, in principle, have no influence on the strengthening technique choice. The knowledge described in this paper is a first step to promote numerical and laboratory research related to opening strengthening and at the same time to support the development of innovating strengthening techniques.