The quest for resilience: The Chilean practice of seismic design for reinforced concrete buildings

Abstract

The satisfactory structural behavior observed during large earthquakes and the high seismicity of the country has conditioned the Chilean society to expect immediate occupancy performance level for their buildings under these extreme events, although the seismic design code in Chile mandates only a scope of life safety performance level. Based on observational and statistical evidence from recent strong earthquakes in Chile, it is concluded that the observed seismic resilience of buildings is a consequence of limiting damage, considering that operational performance and life safety are different challenges that require different approaches; furthermore, to provide society with resilient and safe buildings, both challenges must be met simultaneously and not alternatively. The present article describes the concepts, strategies, and future challenges in the context of the Chilean practice, and the authors describe several lessons learned from the design of thousands of concrete buildings that have experienced earthquakes with a magnitude of 8.0 and higher with limited damage; these lessons have proven to be effective in ensuring resilient structural performance under extreme seismic events.

Sensitivity of the conditional period selection in the structural response using the CMS as target spectrum

“…NCh433, INN (2012); NSR-10,Comité-AIS-100 (2010), respectively) allow the analysis of reinforced concrete structural systems with periods consistent with gross cross-sectional moments of inertia ( T 1 g ), also limiting the maximum allowable story drift ratio to be less than approximately 1%. In practice, these provisions are widely implemented and generate stiffer structures that limit the damage under design basis ground motions (Lagos et al, 2021).…”

Seismic Performance Evaluation of a Chilean RC Building Damaged during the Mw8.8 Chile Earthquake

“…The Chilean approach uses strain as a measure of local performance, unlike the plastic rotation measurement employed in the LATBSDC guide and many other international guides. This difference arises from Chile's structural configuration, which predominantly includes interconnected reinforced concrete structural walls serving as the main resistance system in residential and office buildings [16].…”

Seismic design of buildings: Where to next?

“…Nevertheless, even if the design force at threshold of yielding (or damage) is increased and the ductility demand at ULS is consequently reduced, ductile detailing practice should not be compromised to ensure collapse is avoided and life-safety is guaranteed at severe-extreme earthquakes. This approach is also strongly advocated by a group of senior Chilean engineers [37] after analyzing the building performances in the 2010 Maule earthquake. Adopting the lessons learnt from the 2010 Maule earthquake, the Chilean building design code has been revised in 2011 [38,39] to require buildings to achieve immediate occupancy at DBE and collapse prevention at MCE [37], which is a paradigm shift compared to the design approach currently adopted by other codes (i.e.…”

“…This approach is also strongly advocated by a group of senior Chilean engineers [37] after analyzing the building performances in the 2010 Maule earthquake. Adopting the lessons learnt from the 2010 Maule earthquake, the Chilean building design code has been revised in 2011 [38,39] to require buildings to achieve immediate occupancy at DBE and collapse prevention at MCE [37], which is a paradigm shift compared to the design approach currently adopted by other codes (i.e. to design buildings to remain life safe at DBE).…”