Experimental Study of RC Beams Strengthened with Prestressed near Surface Mounted Helical Rib Steel Wire

2012 ◽  
Vol 204-208 ◽  
pp. 1189-1193
Author(s):  
Chun Sheng Zhang ◽  
Hui Min Hao ◽  
Mei Xiang Zhang ◽  
Ya Hong Ding
Keyword(s):  
High Performance ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Steel Wire ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Near Surface ◽  
Steel Wires ◽  
Near Surface Mounted ◽  
Strengthening Technique

A new reinforcement technique with prestressed helical rib steel wires is presented, and one control beam, three strengthened beams under monotonous loads are tested. The flexural capacity, load-deflection relation, cracks and deformation of reinforced concrete beams are systematically studied under the same initial prestress level and amount of reinforcement, different groove size. The test results indicate that the strengthening technique could significantly improve the first-crack load, steel-yielding load, ultimate load of the beams, and improves the service performance of the strengthened beams. The high performance of the helical rib steel wires is allowed for a better utilization. The results provide a reference for engineering applications.

Concrete Beams Strengthened with Prestressed Near Surface Mounted Helical Rib Steel Wire

2011 ◽  
Vol 255-260 ◽  
pp. 99-104 ◽  
Author(s):  
Ya Hong Ding ◽  
Mei Xiang Zhang ◽  
Chun Sheng Zhang
Keyword(s):  
Ultimate Load ◽  
Fatigue Behavior ◽  
Steel Wire ◽  
Limit State ◽  
Engineering Application ◽  
Concrete Cover ◽  
Near Surface ◽  
Near Surface Mounted ◽  
Strengthening Technique ◽  
Prestressed Beams

This paper presents research on 13 beams with nonprestressed and prestressed helical rib steel wire bonded in sawed grooves in the concrete cover under monotonous loads based on the lack of old strengthening methods. The prestressing, stressing process, first-crack load, steel-yielding load, ultimate load at failure and deformation are systematically studied. The results from the tests show that this new strengthening technique using helical rib steel wire bonding in the concrete cover is an efficient method, which can overcome the problems with peeling of the strengthening material when the surface bonded FRP laminates, also overcome the shortages of nonprestressed beams. The prestressed beams exhibited higher first-crack load, higher steel-yielding load, as well as a larger deformation capacity as compared to nonprestressed strengthened beams, which is important for a construction's lifetime; the fatigue behavior will improve and as a consequence the crack widths will be smaller, which can result in increased durability, which should indicate a more advantageous behavior in the service limit state (SLS). However, the ultimate load at failure is as high as nonprestressed beams, but in relation not as large as for the cracking and yielding. The ultimate load at failure is also higher as compared to non strengthened beams. The results provide a reference for engineering application.

Experimental Study on Flexural Performances of Concrete Beams Strengthened with Near-Surface Mounted (NSM) FRP Reinforcement

2010 ◽  
Vol 163-167 ◽  
pp. 3634-3639
Author(s):  
Li Li Sui ◽  
Tie Jun Liu ◽  
Feng Xing ◽  
Yu Xiang Fu
Keyword(s):  
Experimental Study ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Flexural Stiffness ◽  
Test Results ◽  
Near Surface ◽  
Bending Performance ◽  
Bending Capacity ◽  
Frp Reinforcement ◽  
Near Surface Mounted

This paper illustrates the results of an experimental study on the bending performance of concrete beams strengthened with near-surface mounted (NSM) FRP reinforcement. The critical parameter of the embedded length of NSM-FRP plates was investigated in particularly. The test results indicated that NSM-FRP reinforcement can significantly improve the strength and crack resistance capacity of the concrete beam, reducing the size of cracks. The embedded length of the NSM-FRP plate has distinct influence on the cracking and bending capacity, the flexural stiffness, and the crack developments of the concrete beam. As the embedded length increased, the bending capacity and the flexural stiffness increased correspondingly and the crack developed more intensively.

Comparative study on the flexural strengthening of RC beams using EB CFRP sheets, NSM CFRP bars, P-SWRs, and their combinations

2020 ◽  
pp. 136943322097172
Author(s):  
Yihua Zeng ◽  
Xinghua Li ◽  
Amira Hamdy Ali Ahmed ◽  
Gang Wu
Keyword(s):  
Steel Wire ◽  
Experimental Investigations ◽  
Near Surface ◽  
Flexural Strengthening ◽  
Wire Ropes ◽  
Cfrp Sheets ◽  
Externally Bonded ◽  
Near Surface Mounted ◽  
Strengthening Technique ◽  
Space Requirements

The externally bonded (EB) carbon fiber reinforced polymer (CFRP), near-surface-mounted (NSM) CFRP and the prestressed steel wire ropes (P-SWRs) has been proven to be feasible and reliable flexural strengthening methods for concrete structures. However, debonding issues in EB CFRP sheets (or NSM CFRP bars) and space requirements for edge and spacing clearance of NSM CFRP bars (or P-SWRs) has limited the application of these three strengthening techniques. Therefore, the combinations of these methods need to be investigated and clarified. In this paper, experimental investigations on the flexural performances of seven concrete beams are presented, in which three of the beams were separately strengthened with EB CFRP sheets, NSM CFRP bars, and P-SWRs, respectively, and three of the beams were combinedly strengthened with two of the three techniques. Test results demonstrated that the flexural performances of beams strengthened with the combination with EB CFRP sheets, NSM CFRP bars, and P-SWRs are between the flexural performances of the beams strengthened with the corresponding individual strengthening techniques. It is found that the P-SWRs is favorable for combinations. In case the P-SWRs was combined with EB CFRP sheets or NSM CFRP bars for strengthening, the cracking load was increased to more than 230% and the maximum ultimate load-bearing capacity was increased to 150% when compared with the control beam. The debonding which occurred more or less in the beams strengthened with EB CFRP sheets or NSM CFRP bars or their combination was successfully eliminated by using the combination strengthening technique with P-SWRs. Also, the combination of P-SWRs with EB CFRP sheets or NSM CFRP bars is also favorable to improve the ductility of strengthened beams.

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