Title:
Seismic Strengthening of RC Columns with Straight FRP Anchors
Author(s):
Enrique del Rey Castillo, Jason Ingham and Michael Griffith
Publication:
Symposium Paper
Volume:
327
Issue:
Appears on pages(s):
15.1-15.16
Keywords:
FRP, FRP anchors, seismic strengthening, FRP strengthening, RC structures, RC columns
DOI:
10.14359/51713336
Date:
11/1/2018
Abstract:
The use of Externally Bonded Fiber Reinforced Polymer (EBR-FRP) systems is an established technique for the structural improvement of existing buildings but the technique features disadvantages. Premature FRP-to-concrete debonding has been commonly highlighted as one of the main problems, together with the difficulty of fully wrapping the structural element when the structure presents complex geometries. FRP straight anchors are used to transfer the forces from the FRP sheet into the structural element, ameliorating these two problems, but a comprehensive design method for FRP anchors has not yet been established despite the increased use and research attention given to FRP anchors.
A research project was undertaken involving monotonically testing single-anchors in tension to investigate the behavior and capacity of isolated FRP anchors. However, a number of factors that may have a significant influence on the capacity of the anchors could not be investigated such as the behavior of the anchors when subjected to tension-compression cycles and the effect of dynamic loads. To address some of the aspects not covered within the single-anchor tests, six full-scale reinforced concrete columns were tested using pseudo-static loading, with the aim being to verify that the peak moment developed during testing was forecasted accurately.
Related References:
ACI 374.2R, 2013. Guide for Testing Reinforced Concrete Structural Elements under Slowly Applied Simulated Seismic Loads, Farming Hills, Michigan, U.S.A: American Concrete Institute (ACI) Comittee 374.
ACI 440.2R, 2008. Guide for the Design and Construction of Externally Bonded FRP Systems, Farming Hills, Michigan, U.S.A: American Concrete Institute (ACI) Comittee 440.
Bentz, E. & Collins, M., 2000. Response 2000.
Bournas, D.A. & Triantafillou, T.C., 2009. Flexural Strengthening of Reinforced Concrete Columns with Near-Surface-Mounted FRP or Stainless Steel. ACI Structural Journal, 106(4), pp.495–506.
CNR-DT 200, 2013. Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Existing Structures, Rome, Italy: CNR (Consiglio Nazionale delle Ricerche) - Advisory Committee on Technical Recommendations for Construction.
Goksu, C., Polat, A. & Ilki, A., 2012. Attempt for Seismic Retrofit of Existing Substandard RC Members under Reversed Cyclic Flexural Effects. Journal of Composites for Construction, 16(3), pp.286–299.
Kalfat, R., Al-mahaidi, R. & Smith, S.T., 2013. Anchorage Devices Used to Improve the Performance of Reinforced Concrete Beams Retrofitted with FRP Composites : State-of-the-Art Review. Journal of Composites for Construction, 17(1), pp.14–33.
Kanitkar, R., Smith, S.T. & Lewis, C., 2016. An Experimental Investigation on the splay portion of embedded FRP tension anchors. In Proceedings of The 8th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering (CICE 2016). Hong Kong, China: Department of Civil and Environmental Engineering & Research Institute for Sustainable Urban Development, The Hong Kong Polytechnic University, pp. 413–418.
Kim, I., Jirsa, J.O. & Bayrak, O., 2011. Use of Carbon Fiber-Reinforced Polymer Anchors to Repair and Strengthen Lap Splices of Reinforced Concrete Columns. ACI Structural Journal, 108(5), p.630.
Kim, S.J. & Smith, S.T., 2010. Pullout Strength Models for FRP Anchors in Uncracked Concrete. Journal of Composites for Construction, 14(4), pp.406–414.
Kim, Y., Quinn, K., Ghannoum, W.M. & Jirsa, J.O., 2014. Strengthening of Reinforced Concrete T-Beams Using Anchored CFRP Materials. ACI Structural Journal, 111(5), p.1027.
NZS 1170-5, 2004. Structural Design Actions - Earthquake Actions, Wellington, New Zealand: New Zealand Standards (NZS).
NZS 3101-1, 2006. Concrete Structures Standard, Wellington, New Zealand: New Zealand Standards (NZS).
NZS 3112-2, 1986. Methods of test for concrete, Wellington, New Zealand: New Zealand Standards (NZS).
Priestley, M.J.N., Calvi, G.M. & Kowalsky, M.J., 2007. Displacement-Based Seismic Design of Structures, Pavia, Italy: Istituto Universitario di Studi Superiori di Pavia (IUSS) Press.
Qazi, S., Ferrier, E., Michel, L. & Hamelin, P., 2010. Seismic retrofitting of RC Shear wall with external bonded CFRP. In Proceedings of the Tenth International Symposium on Fiber Reinforced Polymer Reinforcement for Concrete Structures (FRPRCS - 10). Tampa, Florida, USA: American Concrete Institute (ACI).
del Rey Castillo, E., Griffith, M.C. & Ingham, J.M., 2017a. Flexural strenghening of an RC column, University of Auckland, doi: 10.17608/k6.auckland.5440138
del Rey Castillo, E., Griffith, M.C. & Ingham, J.M., 2017b. FRP anchors attributes, University of Auckland, 10.17608/k6.auckland.5188456.
del Rey Castillo, E., Griffith, M.C. & Ingham, J.M., 2017c. Shear strengthening of an RC column and wallet with FRP anchors, University of Auckland, 10.17608/k6.auckland.5440129.
SIKA, 2013a. Sikadur ® 300 Product Data Sheet, Auckland, New Zealand: SIKA (NZ) Ltd.
SIKA, 2013b. SikaWrap ® - 600 C Product Data Sheet, Auckland, New Zealand: SIKA (NZ) Ltd.
SIKA, 2014a. SikaWrap ® FX-50C Product Data Sheet, Auckland, New Zealand: SIKA (NZ) Ltd.
SIKA, 2014b. SikaWrap ® FX-50C Technical Service Report, Madrid, Spain: SIKA Services AG.
Smith, S.T., Zhang, H. & Wang, Z., 2013. Influence of FRP anchors on the strength and ductility of FRP-strengthened RC slabs. Construction and Building Materials, 49, pp.998–1012.
Vrettos, I., Kefala, E. & Triantafillou, T.C., 2013. Innovative Flexural Strengthening of Reinforced Concrete Columns Using Carbon-Fiber Anchors. ACI Structural Journal, 110(1), p.63.