Abstract
This paper presents a study on the shear behavior of reinforced concrete (RC) beams strengthened by jacketing the surfaces of the beams using ultra-high performance fiber reinforced concrete (UHPC). The surfaces of the RC beams were prepared by sandblasting and UHPC was cast in situ over the surfaces of RC beams. The beams were strengthened using two different strengthening configurations; (i) two longitudinal sides strengthening (ii) three sides strengthening. The bond between normal concrete and UHPC was examined by conducting splitting tensile strength and slant shear strength tests on composite cylindrical specimens cast using normal concrete and UHPC. The control and strengthened beam specimens were tested using four-point loading arrangement maintaining different shear span-to-depth ratios. The results of tested beams showed the beneficial effects of strengthening the RC beams using UHPC, as evident from enhancement of the shear capacity and shifting of the failure mode from brittle to ductile with more stiff behavior. In addition, a non-linear finite element model (FEM) was developed to examine the sufficiency of the experimental results used to study the shear behavior of control and strengthened beams. The failure loads and the crack patterns determined experimentally matched well with those predicted using the proposed model with a reasonably good degree of accuracy.
Highlights
Concrete structures need repairing or strengthening when they have some deficiencies in their structural performance and/or durability properties
The results showed that if the strengthening is done by applying highperformance fiber reinforced cementitious composite (HPFRCC) on the tension face as well as on the side faces, the failure load would increase up to 86%
The results showed that the use of high-performance fiber reinforced concrete (HPFRC) jacketing for strengthening has a significant effect in increasing the load carrying capacity by a factor of 2.15
Summary
Concrete structures need repairing or strengthening when they have some deficiencies in their structural performance and/or durability properties. Ultra-high performance concrete (UHPC), which is a hybrid of the cementitious materials and high-tensile strength steel fibers, can be used to strengthen the RC members (Al-osta 2018). The flexural and shear behavior of the RC beams retrofitted using high-performance fiber reinforced concrete (HPFRC) was studied by Alaee et al (2003). The results showed that the proposed strengthening technique was enhanced the structural performance of retrofitted beams through increasing flexural capacity and overall stiffness. Al-Osta et al (2017) developed a finite element model of strengthened beams in flexural using the concrete damage plasticity theory and they found that their proposed model predicted the load–deflection response and the crack patterns in good agreement with the experimental results.
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