Understanding the impact of coastal forests on the propagation of rapidly advancing onshore tsunami bores is difficult due to complexity of this phenomenon and the large amount of parameters which must be considered. The research presented in the thesis focuses on understanding the protective effect of the coastal forest on the forces generated by the tsunami and its ability to reduce the propagation and velocity of the incoming tsunami bore. Concern for this method of protecting the coast from tsunamis is based on the effectiveness of the forest and its ability to withstand the impact forces caused by both the bore and the debris carried along by it. The devastation caused by the tsunami has been investigated in recent examples such as the 2011 Tohoku Tsunami in Japan and the Indian Ocean Tsunami which occurred in 2004. This research examines the reduction of the spatial extent of the tsunami bore inundation and runup due to the presence of the coastal forest, and attempts to quantify the impact forces induced by the tsunami bores and debris impact on the structures. This research work was performed using a numerical model based on the Smoothed Particle Hydrodynamics (SPH) method which is a single-phase three-dimensional model. The simulations performed in this study were separated into three sections. The first section focused on the reduction of the extent of the tsunami inundation and the magnitude of the bore velocity by the coastal forest. This section included the analysis of the hydrodynamic forces acting on the individual trees. The second section involved the numerical modeling of some of the physical laboratory experiments performed by researchers at the University of Ottawa, in cooperation with colleagues from the Ocean, Coastal and River Engineering Lab at the National Research Council, Ottawa, in an attempt to validate the movement and impact forces of floating driftwood on a column. The final section modeled the movement and impact of floating debris traveling through a large-scale model of a coastal forest.

Understanding the impact of coastal forests on the propagation of rapidly advancing onshore tsunami bores is difficult due to complexity of this phenomenon and the large amount of parameters which must be considered. The research presented in the thesis focuses on understanding the protective effect of the coastal forest on the forces generated by the tsunami and its ability to reduce the propagation and velocity of the incoming tsunami bore. Concern for this method of protecting the coast from tsunamis is based on the effectiveness of the forest and its ability to withstand the impact forces caused by both the bore and the debris carried along by it. The devastation caused by the tsunami has been investigated in recent examples such as the 2011 Tohoku Tsunami in Japan and the Indian Ocean Tsunami which occurred in 2004. This research examines the reduction of the spatial extent of the tsunami bore inundation and runup due to the presence of the coastal forest, and attempts to quantify the impact forces induced by the tsunami bores and debris impact on the structures. This research work was performed using a numerical model based on the Smoothed Particle Hydrodynamics (SPH) method which is a single-phase three-dimensional model. The simulations performed in this study were separated into three sections. The first section focused on the reduction of the extent of the tsunami inundation and the magnitude of the bore velocity by the coastal forest. This section included the analysis of the hydrodynamic forces acting on the individual trees. The second section involved the numerical modeling of some of the physical laboratory experiments performed by researchers at the University of Ottawa, in cooperation with colleagues from the Ocean, Coastal and River Engineering Lab at the National Research Council, Ottawa, in an attempt to validate the movement and impact forces of floating driftwood on a column. The final section modeled the movement and impact of floating debris traveling through a large-scale model of a coastal forest.

abstract: This study focused on investigating the ability of a polymeric-enhanced high-tenacity fabric composite called CarbonFlex to mitigate damages from multi-natural hazards, which are earthquakes and tornadoes, in wood-framed structures. Typically, wood-framed shear wall is a seismic protection system used in low-rise wood structures. It is well-known that the main energy dissipation of the system is its fasteners (nails) which are not enough to dissipate energy leading to decreasing of structure's integrity. Moreover, wood shear walls could not sustain their stiffness after experiencing moderate wall drift which made them susceptible to strong aftershocks. Therefore, CarbonFlex shear wall system was proposed to be used in the wood-framed structures. Seven full-size CarbonFlex shear walls and a CarbonFlex wrapped structures were tested. The results were compared to those of conventional wood-framed shear walls and a wood structure. The comparisons indicated that CarbonFlex specimens could sustain their strength and fully recover their initial stiffness although they experienced four percent story drift while the stiffness of the conventional structure dramatically degraded. This indicated that CarbonFlex shear wall systems provided a better seismic protection to wood-framed structures. To evaluate capability of CarbonFlex to resist impact damages from wind-borne debris in tornadoes, several debris impact tests of CarbonFlex and a carbon fiber reinforced storm shelter's wall panels were conducted. The results showed that three CarbonFlex wall panels passed the test at the highest debris impact speed and the other two passed the test at the second highest speed while the carbon fiber panel failed both impact speeds. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2013

The main objective of this study was to investigate and quantify the impact of extreme hydrodynamic forces, similar to those generated by tsunami-induced inundation, on structural elements. As part of a comprehensive experimental program and analytical study, pressures, base shear forces, and base overturning moments generated by hydraulic bores on structural models of various shapes were studied. In addition, the impact force induced by waterborne wooden debris of different shapes and masses on the structural models was also investigated. Two structural models, one with circular and the other with square cross-section, were installed individually downstream of a dam-break wave in a high-discharge flume. Three impounding water heights (550, 850 and 1150 mm) were used to produce dam-break waves, which have been shown to be analogous to tsunami-induced coastal inundation in the form of highly turbulent hydraulic bores. Time-history responses of the structural models were recorded, including: pressures, base shear forces, base overturning moments, lateral displacements, and accelerations. In addition, the flow depth-time histories were recorded at various locations along the length of the flume. Regular and high-speed video cameras were used to monitor the bore-structure interaction. The effect of initial flume bed condition (“wet” or “dry” bed) on the forces and pressures exerted on the structural models were also investigated. Moreover, the vertical distribution of pressure around the models was captured. Simple low-height walls with various geometries were installed upstream from the structural models to investigate their efficiency as tsunami mitigation measures. The experimentally recorded data were compared with those estimated from currently available formulations. The results and analysis of the simulated tsunami-induced bore presented in this study will be of significant use to better estimate forces exerted on structures by tsunami-induced turbulent bores. It is expected that this work will contribute to the new ASCE7 Chapter 6 - Tsunami Loads and Effects in which two of this author’s academic supervisors, Drs. Ioan Nistor and Dan Palermo, are members.