الفهرس | Only 14 pages are availabe for public view |
Abstract In the last two decades, the use of advanced composite materials such as fiber reinforced polymers, (FRP), in strengthening reinforced concrete, (RC), structural elements have been increasing. Researches, design guidelines, and codes concluded that externally bonded FRP could increase capacity of RC elements efficiently. However, the linear stressstrain characteristics of FRP up to failure and lack of yield plateau have a negative impact on the overall ductility of the strengthened RC elements. Strengthening of two-way slabs with FRP in the two directions represents a challenge due to the anticipated reduction in the strength and ductility at onset of failure of FRP in one direction. Not only the linear characteristics of FRP will reduce the slab ductility but also the released energy caused by rupture or bond failure of FRP in one direction, which will affect the bond between the concrete and FRP in the other direction. Use of two types of FRP laminates, which consists of a combination of either carbon and glass fibers or glass and aramid fibers change the behavior of the material to a non-linear behavior (Blarabi et.al.1999) and (Hosny et.al.2005). This thesis aims to study the performance of reinforced concrete two-way slabs strengthened by FRP laminates in two directions The experimental program consists of a total of eight RC two-way slabs with overall dimensions equal to 1500 x 1500 x 70-mm with clear spans equal to 1400 x 1400-mm. The slabs were tested under distributed loading up to failure in order to examine its flexural behaviour. Different fiber types, orientation and different percentages of CFRP and GFRP were attached on the slabs to predict the best strengthening scheme. Ananalytical model based on the stress-strain characteristics of concrete, steel and FRP was adopted and a good agreement was obtained with experimental results.Keywords: CFRP, Composite material, GFRP, HFRP, Hybrid, Reinforced Concrete Strengthening and Two Way Slab. |