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IJSTR >> Volume 4 - Issue 8, August 2015 Edition

International Journal of Scientific & Technology Research  
International Journal of Scientific & Technology Research

Website: http://www.ijstr.org

ISSN 2277-8616

CFRP Strengthening Of Concrete Slabs With And Without Openings

[Full Text]



Asst. Prof. Abdul Ridah Saleh Al-Fatlawi, Hayder Ali Abed



Index Terms: Reinforced Concrete Two-way slab, High Strength Concrete, One central Opening, Two Opening in the Middle Strip, uniformly distributed load, CFRP Sheets.



Abstract: This paper presents an experimental investigation of reinforced concrete slabs with openings and strengthened with (CFRP) sheets, all slabs tested under uniformly distributed load with simply supports on the four edges by using high strength concrete. The experimental work includes testing of sixteen reinforced concrete slab specimens with dimensions (1050x1050) mm and (80) mm depth, as well as a series of tests carried out on construction materials. These slabs were arranged in group (1 to 6), where specimen group (1) is slab without openings and without strengthening, all other remaining groups contained three specimens with opening in the middle strip, one specimen was unstrengthened and the others were strengthened with CFRP sheets using two different schemes. The experimental work also includes studying the existence of a square opening in the center of slab (group (2)) and comparing the division of one square opening into two square opening, so the total area of them was equal to the area of one square opening in group (2). These opening were placed within the middle strip of slab, group (3) was central converging opening (center of the middle strip) and group (4) was central diverging opening (on the side of the middle strip), but group (5) and (6) are represented slabs with two opening in the middle strip converging and diverging respectively. Experimental results showed that the presence of the openings, the unstrengthened specimens showed a decrease in ultimate load capacity between (20.3% - 29.6 %) with respect to the control solid slab especially slabs with two converging opening showed a significant decrease in ultimate load capacity. On the other hand, the test results clearly demonstrated that the use of CFRP depends on the strengthening scheme which leads to a significant improvements by (33.3% - 87.5%) in the cracking load and (26.2% - 55.1%) in the ultimate load compared with unstrengthened slab with opening. The experimental tests also showed the slab specimen with two diagonal diverging opening and strengthening with CFRP by second scheme leading to the best results in cracking load by (36.4%) and ultimate load (21.8%) as compared with the control solid slab.



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