Decision Making Based on Benefit-Costs Analysis: Costs of Preventive Retrofit versus Costs of Repair after Earthquake Hazards

Maria Bostenaru Dan

doi:10.3390/su10051537

Abstract

The reduction of seismic risk through the retrofitting of historic buildings serves catastrophe management. In the application of such measures, actors from the spheres of the passive public, experts, as well as active affected people, are involved. The focus of this work is on planning management in the expert area, with a detailed view on the decision space between goals, means, benefits and costs. Buildings of a typology were modelled, and the models translated using a finite elements software with fibre-based modelling of plasticity. The concept of retrofit elements was developed, in order to connect building surveys, construction management, structural simulations, and costs computation based on devices, all related to these retrofit elements. With a view to the general methodology, in order to compare the costs for repairs to buildings after an earthquake with the costs associated with preventive retrofitting of an undamaged building, several cases were considered: damages on a non-retrofitted building, damages on retrofitted building, retrofitting on an undamaged building, retrofitting on a pre-damaged building, and the subsequent damages in an earthquake for the last two. The innovative part of this research lies in the use of the tension-elongation approach to models of building size. Such an analysis allows not only the description of ways of collapsing and the setting of limit states, but also exactly the specific amount and position of the structural members which fail in certain performance criteria. This type of results can form the basis for interdisciplinary studies, such as economic efficiency studies. The method was applied for early reinforced concrete buildings, which are common in Bucharest, Romania, in a deterministic method which takes into account recorded earthquakes. In conclusion, depending on the size of an earthquake, the timing and extent of the retrofit to be applied differ, if we are to obtain cost savings in preventive retrofitting compared to post-earthquake repair. This is presented through a range of costs curves.

Highlights

This paper addresses decision-making foundations of pre-earthquake retrofitting versus post-earthquake repair of pre-code, reinforced concrete skeleton buildings
Despite their scarcity, such studies are of great importance, since the relationship between benefit and cost of a retrofit measure may influence the application of such a measure in earthquake prone areas, and through their application, save lives in future earthquakes, as well as protecting cultural heritage from irreversible damage through the appropriate choice of an adequate seismic retrofit system and strategy
Apart from Romania, this typology can be found in Portugal, Italy and Greece, among others, as the research in the project CA’REDIVIVUS has shown

Summary

Introduction

This paper addresses decision-making foundations of pre-earthquake retrofitting versus post-earthquake repair of pre-code, reinforced concrete skeleton buildings. Retrofit measures have an impact on the appearance of heritage buildings. This is why a number of actors are involved in a benefit-costs analysis. In Romania, INCERC [3] has published seismic retrofit devices such as those employed in this research. Despite their scarcity, such studies are of great importance, since the relationship between benefit and cost of a retrofit measure may influence the application of such a measure in earthquake prone areas, and through their application, save lives in future earthquakes, as well as protecting cultural heritage from irreversible damage through the appropriate choice of an adequate seismic retrofit system and strategy. Retrofitting measures and strategies considering only the facade were chosen for this study, as this can be compared to energy retrofitting, which has a high level of acceptance in the city, and is being widely performed

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Conclusion