Marc L. Levitan

Loss of life caused by the flooding of New Orleans after Hurricane Katrina: analysis of the relationship between flood characteristics and mortality.

In this article a preliminary analysis of the loss of life caused by Hurricane Katrina in the New Orleans metropolitan area is presented. The hurricane caused more than 1,100 fatalities in the state of Louisiana. A preliminary data set that gives information on the recovery locations and individual characteristics for 771 fatalities has been analyzed. One-third of the analyzed fatalities occurred outside the flooded areas or in hospitals and shelters in the flooded area. These fatalities were due to the adverse public health situation that developed after the floods. Two-thirds of the analyzed fatalities were most likely associated with the direct physical impacts of the flood and mostly caused by drowning. The majority of victims were elderly: nearly 60% of fatalities were over 65 years old. Similar to historical flood events, mortality rates were highest in areas near severe breaches and in areas with large water depths. An empirical relationship has been derived between the water depth and mortality and this has been compared with similar mortality functions proposed based on data for other flood events. The overall mortality among the exposed population for this event was approximately 1%, which is similar to findings for historical flood events. Despite the fact that the presented results are preliminary they give important insights into the determinants of loss of life and the relationship between mortality and flood characteristics.

Lessons from Hurricane Andrew

At dawn on 26 August 1992 Hurricane Andrew made its first landfall on the Louisiana coast at Point Aufer Island. This category four storm had already caused 16,000 M of insured losses [Ref.1] in southern Florida before it hit a rural region of southern Louisiana near Morgan City, 115 km west of New Orleans. The winds caused by Hurricane Andrew effected the built environment of coastal Louisiana in various ways that depended on the level of designer input and the construction quality control. A variety of commercial buildings, dwellings and engineered structures were examined by a United States National Science Foundation funded disaster team and a summary of their findings is presented here; along with some useful design suggestions for hurricane or cyclone-prone areas.

Lessons Learned and Mitigation Options for Hurricanes

The 2005 hurricane season caused unprecedented levels of damage to coastal communities throughout the Gulf of Mexico. Hurricane Katrina and Hurricane Rita were of particular interest to petrochemical and refining companies, given the impacts they had to their onshore operations. Floodwaters and extreme winds from these two hurricanes damaged numerous types of assets, including tanks, cooling towers, generator buildings, process towers, pumps, controllers, utility poles, and transformers. They also caused prolonged power outages, supply disruptions, and widespread employee dislocations, all major contributors to both property and business interruption losses.

Remote Sensing Classification of Hurricane Storm Surge Structural Damage

The concept of spatially-tiered reconnaissance has been introduced as a method of providing increasingly detailed levels of analysis in post-disaster situations [Adams 2006, Womble, 34-38]. Remotely sensed data is becoming more widely available on a systematic basis following natural disasters at various spatial, spectral and temporal resolutions. Depending on these resolutions, each dataset is capable of providing different levels of information. Figure 1 illustrates the three tiers that are used within spatially-tiered reconnaissance – Tier 1 (Regional), Tier 2 (Neighborhood), and Tier 3 (Per building), using storm surge damage sustained after Hurricane Katrina as an example.

A refined method for calculating wind load combinations on open-framed structures

Abstract Literature on open-framed structures has shown that the maximum wind load normal to a set of frames occurs not when the wind is normal to the frames, but rather at some angle to the normal, typically between 20° and 40°. This means that when one set of frames experiences its maximum load, the orthogonal set of frames simultaneously experiences a significant wind load. Currently used procedures for determining wind loads on open-frame structures either ignore this significant load combination or use simplified load combinations. This paper presents an empirical method to determine the maximum normal wind load on a set of frames of an open-frame structure, plus the wind angle at which it occurs and the corresponding load on the orthogonal frame set. It is applicable to open-frame structures rectangular in plan with 3–10 frames in each direction and solidity ratios between 0.1 and 0.5.

DEVELOPMENT OF A LOSS-CONSISTENT WIND AND FLOOD DAMAGE SCALE FOR RESIDENTIAL BUILDINGS

This paper sets forth a new damage scale for use in assessing physical damage to single family houses caused by wind and flood events. A new methodology is presented for assessing both structural and nonstructural physical damage caused by flood events, ranging from slow-rise inundation flooding to coastal high velocity flooding with wave action. The flood scale is integrated with FEMAs HAZUS wind damage scale to allow users to assess a buildings overall level of physical damage on a loss-consistent basis. The damage scale additionally expands and improves FEMAs HAZUS wind damage scale by including two new categories to assess more severe levels of damage. This combined wind and flood damage scale (the WF Damage Scale) ranges from WF-0 (no damage to very minor damage) to WF-6 (complete collapse). Qualitative and quantitative damage descriptions are provided to ease field implementation.

High Resolution Imagery Collection for Post- Disaster Studies Utilizing Unmanned Aircraft Systems (UAS)

This paper examines the use of unmanned aircraft systems (UAS) to capture imagery for use in post-disaster field studies at the neighborhood and individual building level. A discussion of post-disaster imagery collection including satellite, aerial, and ground-based platforms is first presented. Applications of UAS in recent disasters as described in the literature are then surveyed, and a case study investigating UAS capabilities for imagery collection following an EF-3 tornado in northern Alabama on 02 March 2012 is presented. Case study considerations include the multi-rotor unmanned aerial vehicle (UAV) equipment and ground station, onboard imagery devices, flight considerations and capabilities, and imagery and metadata collection capabilities of the UAS. Sample post-tornado imagery of building damage is shown, demonstrating the order of magnitude improvement in imagery resolution compared to traditional post-disaster aerial photography.

Development of a Hurricane Storm Surge Damage Model for Residential Structures

This paper presents the design framework of a hurricane storm surge damage model for residential structures. Current flood damage models include depth-damage functions for slowly rising, low velocity floodwaters, but do not model building damage resulting from coastal flooding with high velocity flows and wave action. The proposed framework uses hazard information obtained from storm surge models and analysis of wave forces combined with building inventory data as inputs to an engineering model that estimates building damage.

Recent Research for Wind Loads on Petrochemical Structures

Structures that are typical of the petrochemical and process industries have structural forms that confound the application of standard wind load estimation techniques. The exposed framing, partial cladding, complex arrangements of ancillaries, and serpentine piping arrangements common in these facilities are beyond the scope of standards such as ASCE 7 (2006). Nevertheless, these structures must be designed to reliably resist wind loads. In 1997 an ASCE task committee released a guide publication entitled, Wind Loads and Anchor Bolt Design for Petrochemical Structures which reported the current state of practice for estimating wind loads for these structures. This document also recommended techniques for estimating wind loads that were based on the combined experience and research of the committee members. This task committee is underway again, and a new version of the publication is expected to be produced shortly. This paper summarizes the results of a series of wind tunnel experiments and analytical investigations performed at Louisiana State University over the past few years, which are relevant to estimation of wind loads for petrochemical structures (Amoroso, 2007). Results from these studies have led to some pending amendments and revisions to the recommendations contained in the original 1997 document.

NIST Advances in Computer-Aided and Computational Methods in Wind Engineering

The paper summarizes recent research and development of computer-aided and computational methods in wind engineering at the National Institute of Standards and Technology (NIST). Specific topics to be covered include: 1. Time-domain database-assisted design of tall, flexible structures excited by turbulent winds inducing dynamic structural responses. 2. Computational Fluid Dynamics (CFD) estimates of aerodynamic pressure on low-rise buildings with geometrical dimensions comparable to the acrosswind integral turbulence length scale. 3. Development of synthetic directional wind speed databases covering on the order of 10,000 years, from measured wind speeds over periods of approximately 30 years. 4. Probability distributions of hurricane wind speeds, Gulf and Atlantic coasts. 5. Extreme wind speeds in non-hurricane prone conterminous United States. 6. Estimates of hurricane-borne missile speeds. 7. Disaster and Failure Events Repository – a new research tool for archival and analysis of post-disaster information and data.