ABSTRACT
From pre stressed cable problems to steel reinforcement addition, including slab or beam opening reinforcement, external CFRP has been applied to concrete bridges with very good results.
First used in Japan to protect building columns against earthquake effects, the CFRP reinforcement application has been extended to many other structural cases. In every case in which you would have designed steel reinforcement in the structure, now you can apply a CFRP strip at the construction site.
Structural openings not foreseen in the original design can be necessary to allow maintenance access or to pass a utility duct. The opening can be made in a slab or beam web; it can be a circular or a rectangular opening.
This paper presents the behavior and the design of rectangular openings in the web of reinforced concrete (RC) beams.
The openings will be executed in a structure loaded, at least, with dead load. Therefore there will be a dynamical problem. Levin & Vershinin (2008) shows that it can happen stress amplification in the structure.
When the problem is to introduce failure in a loaded system one must also be careful of collapse (Ashby & Jones, 2007).
El-Maaddawy & El-Ariss (2012) have tested 16 RC beams with rectangular web openings. Such beams had the following characteristics: concrete C20, CA50 steel, cross section 8.5 x 40 cm and d = 35 cm. All RC beams had 4 ϕ 16 mm of longitudinal CA50 reinforcement.
Through the theoretical code calculation, the paper mentioned above came to the same value for reinforcement as the experiment results showed. RC beam with opening reinforced with CFRP. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig60_1.tif"/>
As a development of this paper, rectangular openings in slabs have been studied.
Vasquez & Karbhari (2003) tested slabs with central openings. The authors commented that “cutouts were formed after casting of slabs to simulate field condition” and that “the CFRP strips were bonded on prior to the cutout being made.”
