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The statistical behavior of wave heights obtained from short-term (i.e., 30-min) wave records during Hurricane Ike was investigated. Spectral data from seven temporary pressure gauges and one National Data Buoy Center (NDBC) buoy moored off the coast of Texas, covering a 12-day period, were used. The wave heights, based on time series reconstructed from the spectra, showed a very good fit to the form of the Rayleigh distribution with Hrms as the parameter of the distribution, whereas the use of the spectrally derived parameter √ 8m0 led to overprediction of the wave heights. Incorporating the spectral band width (α) in the Rayleigh distribution reduced this overprediction. The empirical two-parameter Weibull distribution was also found to represent the wave-height distribution well, but with parameters different from a = 2.126 and b = 8.42. The Tayfun model, used as a representative of Rayleigh-like models, provided the best fit. When converting modelderived significant wave heights to other quantities, such as H1/10, H1/100; and Hmax, the standard Rayleigh coefficients are often used in practice. These led to considerable errors in the present analysis, which also shows that the use of correction factor or a can enhance the results. However, direct estimates of these quantities from a time series simulated using the model-derived spectrum may be an even better alternative to using the standard Rayleigh coefficients. [ABSTRACT FROM AUTHOR]

Posthurricane Ike surveys for almost 2,000 individual wood-framed houses were combined with high resolution numerical hindcasts to investigate the collapse limit state arising from overland waves and surge. For this storm, freeboard above wave crests, wave height, current velocity, and construction date were found to be the most important factors determining survival. Regressions show considerable skill in predicting collapse fragilities and will prove useful in assessing vulnerability. The relatively small range of wind speeds available in the data set did not allow accurate assessments of wind effects on collapse. Several ASCE and FEMA force estimates showed relatively low skill in modeling fragility, in large part because their breaking wave assumption was not accurate over much of the range. However, the use of best-estimate wave heights in force modeling greatly improved accuracy of fragility estimates. Despite the positive results of this study, numerous questions remain. It proved impossible to separate the effects of house age and construction methods. Although computed overland wave heights showed good correlation with fragility, comparison with the limited measured data available showed that wave heights were significantly overpredicted inland. Finally, more accurate standards for integrated and local loads on elevated houses will be necessary to perform detailed structural system-based analyses of fragility. [ABSTRACT FROM AUTHOR]

Observations of wave properties during Hurricane Ike are presented for eight temporary gauges in mean depths of 8.7-15.8 m over a 360-km section of coastline. These gauges cover both the strong (left) and weak (right) sides of the tropical cyclone, with one gauge immediately adjacent to landfall. Maximum significant wave heights are large over the entire section of the coast and reached 5.8 m near landfall but were at some locations significantly limited by the finite depths with significant wave height-to-depth ratios nearing 0.5 at landfall. Nondirectional spectral shapes changed sharply over the course of the storm, from strongly peaked profiles before landfall to much flatter, sometimes multipeaked, spectra as the hurricane came ashore. After landfall, the spectra on Ike's strong side reverted to the sharply peaked form, whereas the weak side spectra were broader and often had multiple peaks. No waves during the storm appeared to be in equilibrium with local winds and water depths, although heights on the strong side of the storm were close. [ABSTRACT FROM AUTHOR]

The Bolivar Peninsula in Texas was severely impacted by Hurricane Ike with strong winds, large waves, widespread inundation, and severe damage. This paper examines the wave and surge climate on Bolivar during the storm and the consequent survival and destruction of buildings. Emphasis is placed on differences between buildings that survived (with varying degrees of damage) and buildings that were completely destroyed. Building elevations are found to be the primary indicator of survival for areas with large waves. Here, buildings that were sufficiently elevated above waves and surge suffered relatively little structural damage, while houses at lower elevations were impacted by large waves and generally completely destroyed. In many areas, the transition from destruction to survival was over a very small elevation range of around 0.5 m. In areas where waves were smaller, survival was possible at much lower elevations. Higher houses that were not inundated still survived, but well-built houses at lower elevations could also survive as the waves were not large enough to cause structural damage. However, the transition height where waves became damaging could not be determined from this study. [ABSTRACT FROM AUTHOR]