Raising the bar in seismic design: cost-benefit analysis of alternative design methodologies and earthquake-resistant technologies

The severe socio-economic impact of recent earthquakes has represented a tough reality check, further confirming the mismatch between society expectations and reality of seismic performance of modern buildings. Life-safety code-compliant design criteria are not enough when dealing with new structures. To raise the bar in terms of structural safety and overall performance objectives, the renewed challenge is defining high-performance buildings able to sustain a design-level earthquake with minimum disruption of business and limited economic losses. To achieve this goal, alternative strategies might be adopted: (a) implementing more advanced design methodologies, (b) increasing the seismic design level, (c) adopting low-damage earthquake-resistant technologies. However, the common perception is that these strategies would lead to unaffordable costs. To support decision-makers, the paper develops a comprehensive parametric study to compare the cost-benefit of reinforced concrete multi-storey buildings designed for increasing levels of seismic intensities (representing a higher seismicity zone or Importance Class) and according to alternative design approaches (Force-based vs. Displacement-based) and technologies (traditional vs. low-damage). Analytical/numerical investigations are carried out to determine the building performance, and loss assessment analyses are performed to compute the Expected Annual Losses of all the parametric configurations. Results, further elaborated through a machine-learning technique, highlight the convenience of implementing more advanced design methodologies, such as a displacement-based approach allowing for a better control of the building response, and the remarkable benefits of applying low-damage technologies, leading to a very high performance and significantly reduced economic losses (> 50%) for a small increase (< 5-10%) of the initial investment cost.

Automated summary

The recent earthquakes have highlighted the mismatch between societal expectations and the reality of seismic performance in modern buildings, leading to severe socio-economic impacts. Current life-safety code-compliant design criteria are insufficient, necessitating the development of high-performance buildings that can withstand design-level earthquakes with minimal disruption and economic losses. Alternative strategies, such as advanced design methodologies, increased seismic design levels, and low-damage technologies, can be adopted to achieve this goal. However, there is a common perception that these strategies would be unaffordable. A comprehensive parametric study in this paper compares the cost-benefit of reinforced concrete multi-storey buildings designed for different seismic intensities and using different design approaches and technologies. The results demonstrate the advantages of advanced design methodologies and low-damage technologies, showing significantly reduced economic losses for a small increase in initial investment cost.