Seismic Retrofit of Real Beam-Column Joints Using Fiber-Reinforced Cement Composites
Publication: Journal of Structural Engineering
Volume 144, Issue 5
Abstract
This paper studies the seismic behavior of old-style reinforced concrete beam-column joints and the effectiveness of an innovative application of fiber-reinforced concrete (FRC) as a seismic strengthening solution. Two real joint subassemblies were extracted from an existing building damaged and demolished after the L’Aquila 2009 earthquake and tested in the laboratory. The joints exhibited poor-quality concrete and reinforcement details typical of old design practice, which are very difficult to reproduce in laboratory simulations. The joint tested in the as-built configuration shows brittle failure with joint diagonal cracking, as commonly observed in the aftermath of recent devastating earthquakes. The FRC thin jacketing prevents the joint panel shear failure, promoting a more favorable beam yielding. This results in a significant increase of the shear strength (until 50%) and energy dissipation (85%). The strengthening phases and the details of the proposed strengthening layout are described. The as-built and strengthened specimens are compared in terms of global and local behavior. Strain measurements on the FRC jacketing are also discussed as an effective design parameter.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The authors express their gratitude to Prof. Francesco Benedettini (University of L’Aquila) for the interest and passion dedicated to these research activities. His premature leaving is a disappointment. In his memory, the authors will continue these research activities with the same passion he conveyed. This study was performed in the framework of PE 2014–2018 joint program DPC Reluis. The materials used for the strengthening of specimens were provided by Mapei SpA, Milan.
References
ACI (American Concrete Institute). (2014). “Building code requirements for structural concrete and commentary.” ACI 318-14, Farmington Hills, MI, 520.
Akguzel, U., and Pampanin, S. (2010). “Effects of variation of axial load and bidirectional loading on seismic performance of GFRP retrofitted reinforced concrete exterior beam-column joints.” J. Compos. Constr., 94–104.
Anderson, M., Lehman, D., and Stanton, J. (2008). “A cyclic shear stress-strain model for joints without transverse reinforcement.” Eng. Struct., 30(4), 941–954.
Antonopoulos, C. P., and Triantafillou, T. C. (2003). “Experimental investigation of FRP-strengthened RC beam-column joints.” J. Compos. Constr., 39–49.
ASCE. (2013). “Seismic evaluation and retrofit of existing buildings.” ASCE/SEI 41-13, Reston, VA.
Baggio, C., et al. (2007). Field manual for post-earthquake damage and safety assessment and short term countermeasures (AeDES), Joint Research Centre, Ispra, Italy.
Bedirhanoglu, I., Ilki, A., and Kumbasar, N. (2013). “Precast fiber reinforced cementitious composites for seismic retrofit of deficient RC joints: A pilot study.” Eng. Struct., 52(Jul), 192–206.
Beres, A., Pessiki, S. P., White, R. N., and Gergely, P. (1996). “Implications of experiments on the seismic behavior of gravity load designed RC beam-to-column connections.” Earthquake Spectra, 12(2), 185–198.
Beschi, C., Riva, P., Metelli, G., and Meda, A. (2014). “HPFRC jacketing of non seismically detailed RC corner joints.” J. Earthquake Eng., 19(1), 25–47.
CEN (European Committee for Standardization). (2005). “Design of structures for earthquake resistance—Part 3: Assessment and retrofitting of buildings.” EN-1998-3/Eurocode 8, Brussell, Belgium.
Cuevas, A., and Pampanin, S. (2017). “Post-seismic capacity of damaged and repaired reinforced concrete plastic hinges extracted from a real building.” 16th World Conf. on Earthquake Engineering, Chilean Association of Seismology and Earthquake Engineering, Santiago, Chile.
Del Vecchio, C., Del Zoppo, M., Di Ludovico, M., Verderame, G. M., and Prota, A. (2017). “Comparison of available shear strength models for non-conforming reinforced concrete columns.” Eng. Struct., 148(1), 312–327.
Del Vecchio, C., Di Ludovico, M., Balsamo, A., Prota, A., Manfredi, G., and Dolce, M. (2014). “Experimental investigation of exterior RC beam-column joints retrofitted with FRP systems.” J. Compos. Constr., 04014002.
Del Vecchio, C., Di Ludovico, M., Prota, A., and Manfredi, G. (2015). “Analytical model and design approach for FRP strengthening of non-conforming RC corner beam-column joints.” Eng. Struct., 87(Mar), 8–20.
Del Vecchio, C., Di Ludovico, M., Prota, A., and Manfredi, G. (2016). “Modelling beam-column joints and FRP strengthening in the seismic performance assessment of RC existing frames.” Compos. Struct., 142, 107–116.
Di Ludovico, M., Balsamo, A., Prota, A., and Manfredi, G. (2008). “Comparative assessment of seismic rehabilitation techniques on a full scale 3-story RC moment frame structure.” Struct. Eng. Mech., 28(6), 727–747.
Di Ludovico, M., Prota, A., Moroni, C., Manfredi, G., and Dolce, M. (2017a). “Reconstruction process of damaged residential buildings outside the historical centres after L’Aquila earthquake: Part I—‘light damage’ reconstruction.” Bull. Earthquake Eng., 15(2), 667–692.
Di Ludovico, M., Prota, A., Moroni, C., Manfredi, G., and Dolce, M. (2017b). “Reconstruction process of damaged residential buildings outside the historical centres after L’Aquila earthquake: Part II—‘heavy damage’ reconstruction.” Bull. Earthquake Eng., 15(2), 693–729.
D.M. (Decreto Ministeriale). (1962). “Provvedimenti per l′edilizia, con particolari prescrizioni per le zone sismiche, G.U. n. 326 del 22/12/1962.” Legge n. 1384, Rome (in Italian).
Dolce, M., Masi, A., Moroni, C., Nigro, D., Santarsiero, G., and Ferrini, M. (2007). “Comportamento ciclico-sperimentale di un nodo trave-pilastro estratto da una struttura esistente in c.a.” ANIDIS. XII Convegno “L’Ingegneria Sismica in Italia, Italian National Association of Earthquake Engineering, Pisa, Italy.
Fabbrocino, G., Verderame, G. M., and Manfredi, G. (2005). “Experimental behaviour of anchored smooth rebars in old type reinforced concrete buildings.” Eng. Struct., 27(10), 1575–1585.
FEMA. (1997). “NEHRP commentary on the guidelines for the seismic rehabilitation of buildings.” FEMA 274, Washington, DC, 488.
Filiatrault, A., Pineau, S., and Houde, J. (1995). “Seismic behavior of steel-fiber reinforced concrete interior beam-column joints.” ACI Struct. J., 92(5), 543–552.
Frascadore, R., et al. (2015). “Local strengthening of RC structures as a strategy for seismic risk mitigation at regional scale.” Earthquake Spectra, 31(2), 1083–1102.
Kalogeropoulos, G. I., Tsonos, A. D. G., Konstandinidis, D., and Tsetines, S. (2016). “Pre-earthquake and post-earthquake retrofitting of poorly detailed exterior RC beam-to-column joints.” Eng. Struct., 109(Feb), 1–15.
Kim, J., and LaFave, J. M. (2012). “A simplified approach to joint shear behavior prediction of RC beam-column connections.” Earthquake Spectra, 28(3), 1071–1096.
Lowes, L. N., and Altoontash, A. (2003). “Modeling reinforced-concrete beam-column joints subjected to cyclic loading.” J. Struct. Eng., 1686–1697.
Melo, J., Varum, H., and Rossetto, T. (2015). “Cyclic behaviour of interior beam-column joints reinforced with plain bars.” Earthquake Eng. Struct. Dyn., 88(Apr), 22–36.
M.I. (Ministero delle Infrastrutture). (2008). “Norme tecniche per le costruzioni.” D.M. 14 Gennaio 2008, Rome (in Italian).
M.LL.PP. (Ministero dei Lavori Pubblici). (1957). “Circolare del ministero dei lavori pubblici n. 1735: Impiego di acciai ad alto limite elastico.” Rome (in Italian).
Naaman, A. E., and Reinhardt, H. W. (2007). “Proposed classification of HPFRC composites based on their tensile response.” Mater. Struct., 39(5), 547–555.
NRC (National Research Council). (2013). “Guide for the design and construction of externally bonded FRP systems for strengthening existing structures.”, Rome, 1–154.
Pagni, C. A., and Lowes, L. N. (2006). “Fragility functions for older reinforced concrete beam-column joints.” Earthquake Spectra, 22(1), 215–238.
Pampanin, S., Bolognini, D., and Pavese, A. (2007). “Performance-based seismic retrofit strategy for existing reinforced concrete frame systems using fiber-reinforced polymer composites.” J. Compos. Constr., 211–226.
Pampanin, S., Calvi, G. M., and Moratti, M. (2002). “Seismic behaviour of R.C. beam-column joints designed for gravity loads.” 12th European Conf. on Earthquake Engineering, Elsevier, Amsterdam, Netherlands, 1–10.
Parra-Montesinos, G. J. (2005). “High-performance fiber-reinforced cement composites: An alternative for seismic design of structures.” ACI Struct. J., 102(5), 668–675.
Paulay, T., and Priestley, M. J. N. (1992). Seismic design of reinforced concrete and masonry buildings, Wiley, New York.
Pohoryles, D. A., et al. (2016). “Use of DIC and AE for monitoring effective strain and debonding in FRP and FRCM-retrofitted RC beams.” J. Compos. Constr., 04016057.
Priestley, M. J. N. (1997). “Displacement-based seismic assessment of reinforced concrete buildings.” J. Earthquake Eng., 1(1), 157–192.
R.D. (Regio Decreto). (1937). “Norme tecniche di edilizia con speciali prescrizioni per le località colpite dai terremoti, G.U. n. 298 del 27/12/1937.” Regio Decreto Legge n. 2105, Rome (in Italian).
Ricci, P., De Risi, M. T., Verderame, G. M., and Manfredi, G. (2016). “Experimental tests of unreinforced exterior beam-column joints with plain bars.” Eng. Struct., 118(Jul), 178–194.
Tsonos, A. G. (2008). “Effectiveness of CFRP-jackets and RC-jackets in post-earthquake and pre-earthquake retrofitting of beam-column subassemblages.” Eng. Struct., 30(3), 777–793.
Verderame, G. M., Ricci, P., De Carlo, G., and Manfredi, G. (2009). “Cyclic bond behaviour of plain bars. Part I: Experimental investigation.” Constr. Build. Mater., 23(12), 3499–3511.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 144 • Issue 5 • May 2018
Copyright
©2018 American Society of Civil Engineers.
History
Received: Feb 28, 2017
Accepted: Oct 3, 2017
Published online: Feb 16, 2018
Published in print: May 1, 2018
Discussion open until: Jul 16, 2018
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.