Seismic Analysis of URM Buildings in S. Africa

Authors: Trevor N. Haas, Thomas van der Kolf

Abstract:

South Africa has some regions which are susceptible to moderate seismic activity. A peak ground acceleration of between 0.1g and 0.15g can be expected in the southern parts of the Western Cape. Unreinforced Masonry (URM) is commonly used as a construction material for 2 to 5 storey buildings in underprivileged areas in and around Cape Town. URM is typically regarded as the material most vulnerable to damage when subjected to earthquake excitation. In this study, a three-storey URM building was analysed by applying seven earthquake time-histories, which can be expected to occur in South Africa using a finite element approach. Experimental data was used to calibrate the in- and out-of-plane stiffness of the URM. The results indicated that tensile cracking of the in-plane piers was the dominant failure mode. It is concluded that URM buildings of this type are at risk of failure especially if sufficient ductility is not provided. The results also showed that connection failure must be investigated further.

Keywords: URM, Seismic Analysis, FEM.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1097281

References:

[1] USGS, Earthquake Facts and Statistics, March 2014, http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php, 28 May 2014.
[2] USGS, Largest and Deadliest Earthquakes by Year, October 2012, http://earthquake.usgs.gov/earthquakes/eqarchives/year/byyear.php, 28 May 2014.
[3] Bloomberg, Japan Sees Quake Damage Bill of up to $309 Billion, Almost Four Katrinas, March 2011, http://www.bloomberg.com/news/ 2011-03-23/japan-sees-quake-damage-bill-of-up-to-309-billion-almostfour- katrinas.html, 28 May 2014., Inter-American Development Bank, Haiti reconstruction cost may near $14 billion, IDB study shows, February 2010, http://www.iadb.org/en/news/webstories/2010-02-16/ haiti-earthquake-reconstruction-could-hit-14-billion-idb,6528.html, 28 May 2014, the guardian, Sichuan quake: China’s earthquake reconstruction to cost $150bn, August 2008, http://www.theguardian.com/world/2008/aug/15/chinaearthquake.china, 28 May 2014., Earthquake Page of Dr. George P.C., 2007, www.drgeorgepc.com/Earthquake2001India.html, 28 May 2014.
[4] The World Bank, Data, Countries and Economies, 2014, http://search.worldbank.org/, 28 May 2014.
[5] Wium, J. (2010), Background to draft SANS 10160 (2009): part 4 seismic loading, Journal of the South African Institution of Civil Engineering, Vol.52 No.1 April 2010, pp 20 -27
[6] Kijko, A., Retief, S. J. P., and Graham, G. (2002). Seismic hazard and risk assessment for Tulbagh, South Africa: Part I–assessment of seismic hazard. Natural Hazards, 26(2):175–201.
[7] Tomaˇzeviˇc, M. (1999). Earthquake-resistant design of masonry buildings, Volume I of Innovation in Structures and Construction. Imperial College Press, London
[8] McNary, W. S. and Abrams, D. P. (1985). Mechanics of masonry in compression. Journal of Structural Engineering, 111(4):857–870.
[9] Lane, J. W., Watermeyer, R. B., and De Villiers, P. D. (1991). Masonry materials and design for movement. SAICE lecture course, Structural Division, Johannesburg, South Africa.
[10] Ewing, B. D. and Kowalsky, M. J. (2004). Compressive behavior of unconfined and confined clay brick masonry. Journal of Structural Engineering, 130(4):650–661.
[11] Ip, F. (1999). Compressive strength and modulus of elasticity of masonry prisms. PhD thesis, Carleton University.
[12] Bosiljkov, V. Z., Totoev, Y. Z., and Nichols, J. M. (2005). Shear modulus and stiffness of brickwork masonry: An experimental perspective. Structural Engineering and Mechanics, 20(1):21–44.
[13] Bruneau, M. (1994). State-of-the-art report on seismic performance of unreinforced masonry buildings. Journal of Structural Engineering, 120(1):230–251.
[14] Page, A. W. (1996). Unreinforced masonry structures-an Australian overview. Bulletin-New Zealand national society for earthquake engineering, 29:242–255.
[15] Truong Hong, L. and Laefer, D. F. (2008). Micro vs. macro models for predicting building damage due to underground movements, The International Conference on Computational Solid Mechanics, 2008.
[16] Bakhteri, J., Makhtar, A. M., and Sambasivam, S. (2004). Finite element modelling of structural clay brick masonry subjected to axial compression. Jurnal Teknologi B, 41(B):57–68.
[17] Louren¸co, P. (1996). Computational strategies for masonry structures, Ph.D. thesis, Technische Universiteit Delft.
[18] Hendry, A. W. (1973). The lateral strength of unreinforced brickwork. The Structural Engineer, 51(2):43–50.
[19] Lawrence, S. J. (1983). Behaviour of brick masonry walls under lateral loading. PhD thesis, The University of New South Wales.
[20] Simsir, C. C., Aschheim, M. A., and Abrams, D. P. (2004). Out-of-plane dynamic response of unreinforced masonry bearing walls attached to flexible diaphragms. In Proceedings of the 13th World Conference on Earthquake Engineering, pages 1–4, Vancouver, BC.
[21] Ghobarah, A. and El Mandooh Galal, K. (2004). Out-of-plane strengthening of unreinforced masonry walls with openings, Journal of Composites for Construction, 8(4):298–305.
[22] Griffith, M. C., Vaculik, J., Lam, N. T.-K., Wilson, J., and Lumantarna, E. (2007). Cyclic testing of unreinforced masonry walls in two-way bending. Earthquake Engineering & Structural Dynamics, 36(6):801– 821.
[23] Yi, T. (2004). Experimental investigation and numerical simulation of an unreinforced masonry structure with flexible diaphragms. PhD thesis, Georgia Institute of Technology.