Seismic performance of repaired lightly-reinforced concrete walls
As a result of the 2010-2011 Canterbury earthquakes, over 60% of the concrete buildings in the Christchurch Central Business District have been demolished. This experience has highlighted the need to provide guidance on the residual capacity and repairability of earthquake-damaged concrete buildings. As limited testing has been performed on repaired components, this study focuses on the performance of severely-damaged lightly-reinforced concrete walls repaired through replacement of reinforcement and concrete in the damaged region. The damage prior to repair included buckling and fracture of longitudinal reinforcement, crushing and spalling of concrete, and, for one of the two specimens, out-of-plane instability of the gross section. Prior to repairing the wall specimens, tensile testing of reinforcement with welded connections was conducted to verify acceptable performance of welds suitable for reinstating the damaged reinforcement. Repairs to the specimens consisted of removal of damaged concrete through either hydro-demolition or jack hammering, followed by cutting and removal of damaged reinforcement and reinstatement of new reinforcement and repair mortar. The two repaired wall specimens were tested using a standard protocol that was identical to that used for one of the two original wall specimens. Aside from a difference in the elastic stiffness, the load-deformation responses of the repaired specimens were similar to that of the originally-tested specimen through to the first loading cycle at 2.0% drift, beyond which strength degradation was more pronounced for the repaired specimens. The overall performance of the repaired walls relative to the original wall indicates that it is feasible to achieve acceptable performance of severely-damaged concrete walls repaired through replacement of reinforcement and concrete in the damaged region.
Marquis F, Kim JJ, Elwood KJ and Chang SE (2017). "Understanding Post-Earthquake Decisions on Multi-Storey Concrete Buildings in Christchurch, New Zealand". Bulletin of Earthquake Engineering, 15(2): 731-758.
Rodriguez M, and Park R (1991). "Repair and Strengthening of Reinforced Concrete Buildings for Seismic Resistance". Earthquake Spectra, 7(3): 439-459.
Cuevas A and Pampanin S (2017). “Post-Seismic Capacity of Damaged and Repaired Reinforced Concrete Plastic Hinges Extracted from a Real Building”. Proceedings of the 16th World Conference on Earthquake Engineering (16WCEE), Santiago, Chile.
Marder KJ, Elwood KJ and Clifton GC (2017). “Post-Earthquake Residual Capacity of Damaged Reinforced Concrete Buildings”. Proceedings of the 16th World Conference on Earthquake Engineering (16WCEE), Santiago, Chile.
Kam WY, Pampanin S and Elwood K (2011). “Seismic Performance of Reinforced Concrete Buildings in the 22 February Christchurch (Lyttelton) Earthquake”. Bulletin of the New Zealand Society of Earthquake Engineering, 44(4): 239-278.
Elwood KJ (2013). “Performance of Concrete Buildings in the 22 February 2011 Christchurch Earthquake and Implications for Canadian Codes”. Canadian Journal of Civil Engineering, 40(8): 759–776.
Sritharan S, Beyer K, Henry RS, Chai YH, Kowalsky M and Bull D (2014). “Understanding Poor Seismic Performance of Concrete Walls and Design Implications”. Earthquake Spectra, 30(1): 307-334.
Wallace JW, Massone LM, Bonelli P, Dragovich J, Lagos R, Lüders C and Moehle J (2012). “Damage and Implications for Seismic Design of RC Structural Wall Buildings”. Earthquake Spectra, 28(S1): S281–S299.
Westenenk B, de la Llera JC, Jünemann R, Hube MA, Besa JJ, Lüders C, Inaudi JA, Riddell R and Jordán R (2013). “Analysis and Interpretation of the Seismic Response of RC Buildings in Concepción during the February 27, 2010, Chile Earthquake”. Bulletin of Earthquake Engineering, 11(1): 69-91.
Marquis F (2015). “A Framework for Understanding Post-Earthquake Decisions on Multi-Storey Concrete Buildings in Christchurch, New Zealand”. Master’s Thesis, University of British Columbia, Vancouver, Canada.
Carvallo JF and Alcaíno PE (2012). “Behavior of Reinforced Concrete Buildings in Viña del Mar: Lessons of February 27th 2010 Earthquake”. Proceedings of the 15th World Conference on Earthquake Engineering (15WCEE), Lisbon, Portugal.
Sherstobitoff J, Cajiao P and Adebar P (2012). “Repair of an 18-Story Shear Wall Building Damaged in the 2010 Chile Earthquake”. Earthquake Spectra, 28(S1): S335-S348.
AS/NZS 1554.3 (2014). “Structural Steel Welding Part 3: Welding of Reinforcing Steel.” Standards New Zealand, Wellington, New Zealand.
Lu Y (2017). “Seismic Design of Lightly Reinforced Concrete Walls”. PhD Thesis, University of Auckland, Auckland, New Zealand.
Lu Y, Henry RS, Gultom R and Ma QT (2015). "Experimental Testing and Modelling of Reinforced Concrete Walls with Minimum Vertical Reinforcement". Proceedings of the Annual Conference of New Zealand Society of Earthquake Engineering (NZSEE), Rotorua, New Zealand.
ACI 374.2R-13 (2013). “Guide for Testing Reinforced Concrete Structural Element under Slowly Applied Simulated Seismic Loads”. American Concrete Institute, Farmington Hills, Michigan.
ACI ITG-5.1-07 (2008). “Acceptance Criteria for Special Unbonded Post-Tensioned Precast Structural Walls Based on Validation Testing and Commentary”. American Concrete Institute, Farmington Hills, Michigan.
NZS 3101:2006 A3 (2017). “Concrete Structures Standard Amendment 3”. Standards New Zealand, Wellington, New Zealand.
Copyright (c) 2017 Christopher J. Motter, Aaron B. Clauson, James C. Petch, Matias A. Hube, Richard S. Henry, Kenneth J. Elwood
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