Analysis of the Duration of High Winds During Landfalling Hurricanes

Gregory A Kopp,Si Han Li,H P Hong

doi:10.3389/fbuil.2021.632069

Abstract

The duration of wind storms over a threshold wind speed value is known to be an important parameter in determining damage and losses, with losses tending to increase with the duration. This is because peak pressures tend to increase with longer duration, many building components and cladding systems are vulnerable to different types of fatigue mechanisms, and the yielding of linear elastic materials in the plastic range depends on the number of load cycles. A hurricane model was used to examine the duration of high winds in the United States at Miami, Galveston, and Charleston with the goal of establishing duration statistics for hurricanes as a function of peak wind speed. It was found that the duration of high winds, defined as the time that the 10 min wind speeds are within 30% of the peak 10 min wind speed, had a significant variation with a range from tens of minutes to more than 20 h, depending on location. The median duration ranged from 1.5 to 4 h at the three locations, depending on location and the design wind speed level (i.e., the risk Category of the building). These results were used to establish a simple normalized model for wind speed as a function of time, which could be used together with the design wind speed to establish load cycles for design.

Highlights

The duration of storms, which is determined by the combination of the storm size and translation speed, is known to be an important parameter in determining damage and losses, for several reasons
The objective of this study is to examine the variation of duration for hurricanes near their design wind speeds
Based on the statistical analysis of hurricane passage data at the three locations, Eq 5 provides a model of the normalized wind speed time history for the design cyclone, which can be made dimensional using the design wind speed, such as those from ASCE 7–16 in Table 1, with the duration from Figure 8

Summary

Introduction

The duration of storms, which is determined by the combination of the storm size and translation speed, is known to be an important parameter in determining damage and losses, for several reasons. The statistics for gust wind speeds and peak aerodynamic (i.e., pressure) loads yield larger magnitudes with longer durations, all else being equal (Cook and Mayne, 1979). Many components have significant non-linear yield characteristics. One example is nailed connections used in wood-frame construction, that can be modeled as bi-linear with extensive yielding (i.e., pull-out), which is strongly dependent on the number of peak pressure cycles for complete withdrawal (Morrison and Kopp, 2011) and, on the storm duration (Guha and Kopp, 2014). Rainwater penetration contributes significantly to losses (Sparks et al, 1994; Standohar-Alfano et al, 2017)

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