Post-event Reconstruction Research Articles

CAESAR II Tool: Complementary Analyses for Emergency Planning Based on Seismic Risks Impact Evaluations

Italy is a country with high seismic hazard, however since the delay in the seismic classification of the national territory, most of the existing building heritage does not comply with the current technical standards for buildings. The seismic events that have hit different Italian regions in recent years have highlighted the complexity of the challenge for the public bodies both in the emergency management and post-event reconstruction and in the planning of effective risk prevention and mitigation measures to be implemented in ‘peacetime’. These difficulties concern, in particular, the capacity to properly manage the financial and technical resources available and to identify the intervention priorities throughout the entire emergency cycle. For correct management, the priority is to quantify and localize, through simulations, the quantification of probable damages and to evaluate in terms of cost-benefits the possible alternative strategies for mitigation, also taking into account the potential, in terms of cost-effectiveness, of integrated measures for seismic and energy retrofitting. In this framework, the project CAESAR II (Complementary Analyses for Emergency planning based on Seismic Risks impact evaluations) has been developed as a Decision Support System for Public Authorities in charge of developing Disaster Risk Reduction plans, with the possibility of programming mid to long-term investments for public and private properties, as well as defining custom financial support mechanisms and tax incentives.

Road Accident Reconstruction Using On-board Data, Especially Focusing on the Applicability in Case of Autonomous Vehicles

The application of Event Data Recorder (EDR) in passenger cars and vans has been compulsory in the USA since 2014. In the European Union, every passenger car and vehicle manufactured and released must have e-call systems since April 2018. However, neither the data recorded in Event Data Recorders regulated by the current standards nor the data recovered from e-call systems are enough to reconstruct the movements of the vehicle before and after the accident to a degree that the accident could be analyzed in the perspective of liability. The continuous expansion of autonomous vehicle functions – which will inevitably lead to completely autonomous vehicles – makes it particularly justifiable that all vehicles should possess EDR functions and that these data recorders shall store the satisfactory number of parameters for the vehicle's full movement reconstruction.In the article, we will present a process of defining a data package – which will include a definition process for both the data points and the frequency of measuring and recording – that enables the post-event reconstruction of the full motion process, the vehicle movements and the evaluation of liability issues in both regular and irregular operation of autonomous and partially autonomous vehicles.

A stellar occultation by Vanth, a satellite of (90482) Orcus

A stellar occultation by the large trans-Neptunian object (90482) Orcus was predicted to occur on 2017 March 07. Observations were made at five sites in North and South America: the 0.6-m Astronomical Telescope of the University of Stuttgart (ATUS) at Sierra Remote Observatories, California; Las Cumbres Observatory's 1-m telescope at McDonald Observatory, Fort Davis, Texas (ELP); NASA's 3-m InfraRed Telescope Facility (IRTF) on Mauna Kea, Hawai'i; the 0.6-m Southeastern Association for Research in Astronomy (SARA-CT) telescope at Cerro Tololo, Chile; and the 4.1-m Southern Astrophysical Research (SOAR) telescope on Cerro Pachón, Chile. High-speed, visible-wavelength images were taken at all sites, in addition to simultaneous K-band images at the IRTF. Solid-body occultations were observed from two sites. Post-event reconstruction suggested an occultation of two different stars observed from two different sites. Follow-up, speckle imaging revealed a second star, which verified that the occulting body in both cases was Orcus’ satellite, Vanth. The two single-chord detections, with an anomalously large timing delay in one chord, have lengths of 291 ± 125 km and 434.4 ± 2.4 km. The observations, combined with a non-detection at a nearby site, allow a tight constraint of 443 ± 10 km to be placed on Vanth's size (assuming it is spherical). A 3-σ upper limit of 1–4 μbar (depending on constituent) is found for a global Vanth atmosphere. The immersion and emersion profiles are slightly different, with atmospheric constraints 40% higher on immersion than on emersion. No rings or other material were detected within ten thousand kms of Vanth, and beyond 8010 km from Orcus, to the tightest optical depth limit of ∼0.1 at ∼5 km scale. The occultation probed as close as 5040 km from Orcus, placing an optical depth limit of ∼0.3 at ∼5 km scale on any encircling material at that distance.

Epidemic characteristics and prophylaxis/control measures of infectious diseases caused by hydrological disasters

Hydrological disasters are associated with infectious disease outbreaks and epidemics. Hydrological disasters will lead to water pollution, increased vulnerability to diseases, and increased density of vectors. These factors will facilitate the outbreaks of water-borne/food-borne diseases, vector-borne diseases, and air-borne/contagious diseases. Pre-event preparedness for disasters and post-event reconstruction of both disease surveillance system and water-supply system are key measures to prevent infectious disease outbreaks caused by hydrological disasters. This study reviews the domestic and overseas experiences of controlling infectious diseases after hydrologic disasters, outlines the spectrum of post-disaster infectious disease as well as their epidemiological characteristics, and provides practicable suggestions accordingly.

De-aggregation of community resilience goals to obtain minimum performance objectives for buildings under tornado hazards

The paradigm of performance-based engineering (PBE) provides a framework for engineers and planners to achieve desired levels of performance and functionality of building clusters and civil infrastructure systems that are essential for community resilience and well-being. While it is recognized that resilience of a community must be supported by individual buildings and engineered facilities, the relation between community resilience goals and minimum performance criteria of individual structures enabling such goals through engineering practices does not yet exist. In this study, we first propose a path forward to establish this relation in a quantitative manner. We then illustrate the feasibility of the proposed framework by de-aggregating the resilience goals of a community residential building cluster through an inverse multi-objective optimization formulation to obtain the minimum performance objectives for residential buildings, for tornado hazards. Once the minimum building performance criteria are determined, they can be utilized as the target building performance for new constructions, pre-event strengthening or post-event reconstruction. The overarching aim of this framework is to relate engineering design and retrofit practices to socioeconomic expectations of a community as a whole, and to provide a vehicle for risk-informed resilience-based decision-making under natural hazard events.

Modeling Tsunami Induced Debris Impacts on Bridge Structures using the Material Point Method

Bridges represent a key part of infrastructure, playing a critical role in emergency response and post-event reconstruction. In this context, it is important for bridges to be able to survive both ground shaking and the effects of tsunamis. This paper focuses on numerically modeling bridge loading due to tsunamis. Although several studies have addressed the effect tsunami loads on bridges, few have examined the influence of debris carried by the tsunami. These problems involve complex contact interactions between solids and fluids that are not easily accommodated using typical fluid-oriented or solids-oriented numerical frameworks. In this paper the material point method (MPM) is used to address fluid and solid (moving and stationary) interactions with emphasis in evaluating demands on bridge superstructures by tsunami-driven debris.Two parametric studies have been conducted in this study. The first is aimed at understanding the influence of the contact area and the eccentricity of impact on the impact forces. The results show that the effect of these two factors are reduced with an increase in longitudinal length of the solid object. The second part of the study tries to evaluate the difference between tsunami driven debris impact loads and in-air debris impact loads. The results indicate that tsunami driven debris impacts tend to be larger by upto 35% compared to only in-air impact forces calculated using empirical equations.

The formation and breach of a short-lived landslide dam at Hsiaolin village, Taiwan — part I: Post-event reconstruction of dam geometry

In this paper, technologies from multiple disciplines are used to reconstruct the shape of the Hsiaolin landslide dam, a short-lived landslide dam (SLD), that was triggered by Typhoon Morakot. Here, the formation, failure mode and breaching process of this SLD are investigated. The results indicate that the overtopping time and the debris budget constrained the dam geometry. The inferred volume of the Hsiaolin landslide dam (15.4 million m 3) is much smaller than the actual landslide volume (25.2 million m 3) even considering the rock-mass dilation and debris entrainment. Meanwhile, a 46% error could be induced if an over-simplified equation (a function of the dam height, length and width) is used to calculate the dam volume. The saddle of the dam crest, which is where overtopping occurred, could be used as a reference to measure the dam height and length. Accordingly, the determined dam dimensions of height (44 m), length (370 m) and width (1500 m) are suggested to be the representative geometrical indices that influenced the stability of the Hsiaolin landslide dam. The flow rate of the dammed river, another variable relevant to dam stability, was determined from a run-off simulation. It is suggested that, instead of the peak flow before the dam formation, the flow rate during the blockage period (2974 m 3/s) should be used as the training data for building a statistical model for stability predictions. Finally, the low hydraulic gradient at the toe of the dam's surface and the high safety factor of the dam slope indicate that the piping and slope instability were irrelevant to the failure of the Hsiaolin short-lived landslide dam. It is postulated that overtopping (about one hour after the blockage) dominated the failure process of this heavy-rainfall-induced landslide dam.

Optimizing Regional Earthquake Mitigation Investment Strategies

Regional mitigation analysis is a systematic procedure to determine how much to spend on mitigation versus post-event reconstruction and to prioritize alternative mitigation strategies. It requires at least the following information: magnitude and character of the regional risk, costs and benefits associated with all possible mitigation alternatives, available budget, and specific regional objectives for risk management. Currently available loss estimation models provide increasingly comprehensive estimates of regional risk, but offer little guidance about how to use that information to make mitigation resource allocation decisions. This paper describes a linear program developed to support systematic regional earthquake mitigation analysis, and illustrates its application through a case study in Los Angeles County. Results suggest which buildings—by structural type, occupancy type, and census tract location—should be upgraded so as to minimize total mitigation and expected post-earthquake reconstruction costs.