Globally, hazards are increasingly threatening housing each year, and housing constructed outside the formal sector may be particularly vulnerable. Yet, limited studies have investigated the perceptions of those responsible for designing and building this housing. These safety perceptions motivate the informal housing construction practices that ultimately determine housing safety. Thus, this study investigates the multi-hazard housing safety perceptions of individuals involved with housing construction in Puerto Rico. We surveyed 345 builders and hardware store employees across Puerto Rico to understand their perceptions of expected housing damage in hurricanes and earthquakes, important mitigation measures, and barriers to safer housing construction. Our results reveal that prior hazard experience did not influence perceptions of expected housing damage, but previous housing construction experience did. Respondents viewed wood and concrete housing as less safe in hurricanes and earthquakes, respectively. Yet, respondents appeared uncertain about the importance of mitigation measures for concrete houses in earthquakes, likely due to a combination of limited earthquake experience and “hidden” reinforcement detailing in a reinforced concrete house. Interestingly, our results also show that respondents perceive technical construction capacity as a major barrier to safer informal housing construction rather than resource constraints alone. These findings suggest areas for technical construction capacitymore »
This content will become publicly available on September 22, 2023
Seismic safety of informally constructed reinforced concrete houses in Puerto Rico
More than 1.6 billion people worldwide live in informally constructed houses, many of which are reinforced with concrete. Patterns of past earthquake damage suggest that these homes have significant seismic vulnerabilities, endangering their occupants. The characteristics of these houses vary widely with local building practices. In addition, these vulnerabilities are potentially exacerbated by incremental construction practices and building practices that address wind/flood risk in multi-hazard environments. Yet, despite the ubiquity of this type of construction, there have not been efforts to systematically assess the seismic risks to support risk-reducing design and construction strategies. In this study, we developed a method to assess the seismic collapse capacity of informally constructed housing that accounts for local building practices and materials, quantifying the effect of building characteristics on collapse risk. We exercise the method to assess seismic performance of housing in the US. Caribbean Island of Puerto Rico, which has high seismic hazard and experiences frequent hurricanes. This analysis showed that heavy construction, often due to the addition of a second story, and the presence of an open ground story leads to a high collapse risk. Severely corroded steel bars could also worsen performance. Although houses with infill performed better than those with more »
- Publication Date:
- NSF-PAR ID:
- 10371790
- Journal Name:
- Earthquake Spectra
- Volume:
- 39
- Issue:
- 1
- Page Range or eLocation-ID:
- p. 5-33
- ISSN:
- 8755-2930
- Publisher:
- SAGE Publications
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Studies of recorded ground motions and simulations have shown that deep sedimentary basins can greatly increase the damage expected during earthquakes. Unlike past earthquake design provisions, future ones are likely to consider basin effects, but the consequences of accounting for these effects are uncertain. This article quantifies the impacts of basin amplification on the collapse risk of 4- to 24-story reinforced concrete wall building archetypes in the uncoupled direction. These buildings were designed for the seismic hazard level in Seattle according to the ASCE 7-16 design provisions, which neglect basin effects. For ground motion map frameworks that do consider basin effects (2018 USGS National Seismic Hazard Model), the average collapse risk for these structures would be 2.1% in 50 years, which exceeds the target value of 1%. It is shown that this 1% target could be achieved by: (1) increasing the design forces by 25%, (2) decreasing the drift limits from 2.0% to 1.25%, or (3) increasing the median drift capacity of the gravity systems to exceed 9%. The implications for these design changes are quantified in terms of the cross-sectional area of the walls, longitudinal reinforcement, and usable floor space. It is also shown that the collapse risk increases tomore »
-
In recent years, several locations in the United States have been experiencing a significant increase in seismicity that has been attributed to oil and gas production. As oil and natural gas production in the United States continues to increase, it is expected that the seismic hazard in these locations will continue to experience a corresponding upsurge. However, many urban structures in these locations are not designed to withstand these increasing levels of seismicity. Accordingly, it is crucial to develop methodologies that can help us quantify the seismic performance of these structures, establish their risk levels, and identify optimal retrofit strategies that will enhance the seismic resilience of these structures. In this context, structural health monitoring (SHM) plays an important role in understanding the seismic performance of structures. SHM can be used, in conjunction with finite element modelling, to provide a realistic representation of the structural performance during a seismic event. In this paper, a framework for seismic risk assessment of reinforced concrete buildings based on SHM is presented. The framework combines nonlinear finite element modeling and SHM data to establish the seismic fragility profile of the structure. The approach is illustrated on a multi- story reinforced concrete structure located onmore »
-
Abstract: This paper investigates the seismic response analysis of the 9-story SAC building equipped with pressurized sand dampers, a new type of low-cost energy dissipation device where the material enclosed within the damper housing is pressurized sand. The strength of the pressurized sand damper is proportional to the externally exerted pressure on the sand via prestressed steel rods; therefore, the energy dissipation characteristics of a given pressurized sand damper can be adjusted according to a specific application. The strong pinching behavior of pressurized sand dampers was characterized with a previously developed three-parameter Bouc-Wen hysteretic model that for this study was implemented in the open source code OpenSees with a C++ algorithm, and it was used to analyze the seismic response of the 9-story SAC building subjected to six strong ground motions that exceed the design response spectrum for all soil categories. The paper shows that for the family of strong ground motions used in this study, pressurized sand dampers with strength of the order of 5%–10% of the weights of their corresponding floors were able to keep the interstory drifts of the 9-story SAC building at or below 1%, while base shears and peak plastic hinge rotations were reduced inmore »
-
How residents perceive housing safety affects how structures are designed, built, and maintained. This study assesses the perceptions of housing safety through a survey of over 450 individuals in communities that received post-disaster housing reconstruction assistance following 2013’s Typhoon Yolanda, and that were potentially vulnerable to earthquakes. We analyzed how housing design factors, post-disaster program elements, personal characteristics, and hazard type and exposure influenced safety perceptions. Overall, individuals were most concerned with the safety of their roofs during hazard events and perceived their houses would be less safe in a future typhoon than a future earthquake. Housing material significantly impacted safety perceptions, with individuals in wood houses perceiving their houses to be the least safe. Individuals living in areas more exposed to hazards also perceived their houses to be less safe. Being relocated after the typhoon, witnessing good or bad practices during reconstruction, and prior disaster experience also significantly influenced perceptions of housing safety. These results are used to make recommendations on how implementing organizations can most beneficially intervene with program factors to improve local understanding of housing safety.
