Earthquakes frequently occur around the world and make us think about in improve our construction systems and design, and considering new or better alternatives for construction in which will reduce damage and casualties. This research is based on the 2010 earthquakes in Chile of 8.8 Richter magnitude scale and 2012 New Zealand earthquake of 6.3 magnitude; at least 704 people died, and thousands were injured, and many buildings presented failures or total collapse.
Previous works on the earthquakes indicated regular behavior of reinforced concrete buildings with structural walls. However, some buildings suffered significant damage associated with global or local collapse due to diagonal cracking and flexural-compression failure. Structural walls located at the ground floor presented tension-compression failure, which was probably provoked by high axial forces at the walls extreme ends could cause this failure in such places lacking bracing and confinement.
In New Zealand, the structures analyzed were the CTV Building, Pyne Gould Corporation Building, Grand Chancellor Hotel and the Forsyth Barr Building that were affected by the high ground accelerations, of 2.2g and the New Zealand Construction Code used in these building did not include the concept of ductility and the spectral acceleration was, therefore, lower.
In Chile, the structures analyzed suffer from flexural compression failure, tension compression failure provoked buckling of the transversal wall (where the main bars presented lack of seismic hooks), deficient reinforcement due to small bar diameters, and large spaces between the transversal reinforcement. Plan and elevation irregularities were also an important factor that caused the structures to fail and collapse.
To avoid these problems, some factors must be considered: regulations in construction design, reevaluation of the seismic hazard coefficient, reinforcing steels in wall, the optimal length of seismic hooks and structural walls and different thickness levels (higher than 200 mm). The current article also presents these recommendations in view of the requirements for earthquake proof construction in Ecuador.
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Reference : Aguilar, M.C.A.A.; Haro, A.G.; Sánchez, P.C. (2016). Main Reasons of Structural Wall Collapse in Chile 2010 and New Zealand 2011 - Implications For Ecuador. TOCIEJ.; DOI: 10.2174/1874149501610010469