Title:
RESTORATION OF CONCRETE BEAMS PRE-SUBJECTED TO CYCLES OF SHEAR DAMAGE
Author(s):
Tamer El-Maaddawy
Publication:
Structural Journal
Volume:
112
Issue:
3
Appears on pages(s):
347-358
Keywords:
composites; near-surface-mounted; restoration; shear damage.
DOI:
10.14359/51687409
Date:
5/1/2015
Abstract:
The shear response of reinforced concrete beams predamaged
in shear and then retrofitted with near-surface-mounted (NSM)
composite strips has been investigated in this paper. A total of
18 tests were conducted. Prior to restoration, the specimens were: undamaged; precracked after three cycles of loading up to first shear cracking-unloading; or prefailed in shear after one cycle of loading-unloading. The NSM composite reinforcement remarkably improved the shear response. The shear strength gain decreased with an increase in the amount of internal stirrups. Changing the angle of inclination of the NSM composites from 90 to 45 degrees increased the shear strength gain of the specimens without stirrups but had a less pronounced effect on the shear strength gain of the specimens with internal stirrups/prefailed in shear. The presence of
shear cracks prior to restoration did not reduce the shear strength gain provided by the NSM composites. The NSM composite system fully restored the shear capacity of the prefailed specimens. The contributions of the NSM composites to the shear resistance determined experimentally were compared with predictions of a published analytical approach.
Related References:
1. De Lorenzis, L., and Teng, J., “Near-Surface Mounted FRP Reinforcement: An Emerging Technique for Strengthening Structures,” Composites. Part B, Engineering, V. 38, No. 2, 2007, pp. 119-143. doi: 10.1016/j.compositesb.2006.08.003
2. Anwarul Islam, A. K. M., “Effective Methods of Using CFRP Bars in Shear Strengthening of Concrete Girders,” Engineering Structures, V. 31, No. 3, 2009, pp. 709-714. doi: 10.1016/j.engstruct.2008.11.016
3. El-Hacha, R., and Wagner, M., “Shear Strengthening of Reinforced Concrete Beams using Near-Surface Mounted CFRP Strips,” Proceedings of the Ninth International Symposium on Fiber-Reinforced Polymer Reinforcement for Concrete Structures (FRPRCS-9), Sydney, Australia, 2009.
4. Dias, S., and Barros, J., “Shear Strengthening of RC T-Section Beams with Low Strength Concrete Using NSM CFRP Laminates,” Cement and Concrete Composites, V. 33, No. 2, 2011, pp. 334-345. doi: 10.1016/j.cemconcomp.2010.10.002
5. De Lorenzis, L., and Nanni, A., “Shear Strengthening of Reinforced Concrete Beams with Near-Surface Mounted Fiber-Reinforced Polymer Rods,” ACI Structural Journal, V. 98, No. 1, Jan.-Feb. 2001, pp. 60-68.
6. Nanni, A.; Di Ludovico, M.; and Parretti, R., “Shear Strengthening of a PC Bridge Girder with NSM CFRP Rectangular Bars,” Advances in Structural Engineering, V. 7, No. 4, 2004, pp. 297-309. doi: 10.1260/1369433041653570
7. Barros, O., and Dias, S., “Near Surface Mounted CFRP Laminates for Shear Strengthening of Concrete Beams,” Cement and Concrete Composites, V. 28, No. 3, 2006, pp. 276-292. doi: 10.1016/j.cemconcomp.2005.11.003
8. Dias, S., and Barros, J., “Shear Strengthening of T Cross Section Reinforced Concrete Beams by Near-Surface Mounted Technique,” Journal of Composites for Construction, ASCE, V. 12, No. 3, 2008, pp. 300-311. doi: 10.1061/(ASCE)1090-0268(2008)12:3(300)
9. Rizzo, A., and De Lorenzis, L., “Behavior and Capacity of RC Beams Strengthened in Shear with NSM FRP Reinforcement,” Construction and Building Materials, V. 23, No. 4, 2009, pp. 1555-1567. doi: 10.1016/j.conbuildmat.2007.08.014
10. Cisneros, D.; Arteaga, A.; De Diego, A.; and Alzate, A., “Experimental Study on NSM FRP Shear Retrofitting of RC Beams,” Proceedings of the Sixth International Conference on FRP Composites in Civil Engineering (CICE-2012), Rome, Italy, June 2012, 8 pp.
11. Dias, S., and Barros, J., “Performance of Pre-Cracked RC Beams Shear Strengthened with NSM CFRP Laminates,” Proceedings of the Sixth International Conference on FRP Composites in Civil Engineering (CICE-2012), Rome, Italy, June 2012, 8 pp.
12. Chaallal, O.; Mofidi, A.; Benmokrane, B.; and Neale, K. W., “Embedded Through-Section FRP Rod Method for Shear Strengthening of RC Beams: Performance and Comparison with Existing Techniques,” Journal of Composites for Construction, ASCE, V. 15, No. 3, 2011, pp. 374-383. doi: 10.1061/(ASCE)CC.1943-5614.0000174
13. El-Maaddawy, T., and Chekfeh, Y., “Shear Strengthening of T-Beams with Corroded Stirrups Using Composites,” ACI Structural Journal, V. 110, No. 5, Sept.-Oct. 2013, pp. 779-790.