THE UNIVERSITY OF SOUTH ALABAMA COLLEGE OF ENGINEERING PHYSICAL MODELING OF WAVE TRANSMISSION FOR SUBMERGED AND EMERGENT BREAKWATERS USED IN LIVING SHORELINES BY Richard J. Allen A Thesis Submitted to the Graduate Faculty of the University of South Alabama in partial fulfillment of the requirements for the degree of Master of Science in Department of Civil Engineering May 2013 Approved: Date: Chair of Thesis Committee: Dr. Webb Committee Member: Dr. Douglass Committee Member: Dr.
Powers Chair of Department: Dr. White Director of Graduate Studies: Dr. Thomas Dean of the Graduate School: Dr. Keith Harrison PHYSICAL MODELING OF WAVE TRANSMISSION FOR SUBMERGED AND EMERGENT BREAKWATERS USED IN LIVING SHORELINES A Thesis Submitted to the Graduate Faculty of the University of South Alabama in partial fulfillment of the requirements for the degree of Master of Science in Department of Civil Engineering by Richard J., University of South Alabama, 2011 May 2013 ACKNOWLEDGMENTS This research was made possible through support provided by the U.
Department of Commerce through the National Oceanic and Atmospheric Administration through The University of Southern Mississippi under terms of Agreement No. The opinions expressed herein are those of the authors and do not necessarily reflect the views of the U. Department of Commerce, the National Oceanic and Atmospheric Administration or The University of Southern Mississippi. The author would like to take the time to thank all of the individuals who made this research possible.
Foremost, the author appreciates the support received from the Department of Civil Engineering faculty, namely Dr. Bret Webb and Dr. Scott Douglass for acquiring funding, and Dr. Eric Steward for assistance in determining the physical properties of the oyster shell substrate used in the ReefBLKsSM.
Furthermore, thanks should be given to Carl Ferraro from the Alabama Department of Conservation and Natural Resources - Coastal Division for the acquisition of oyster shell and netting material used in the bagged oyster shell experiments as well as Scott Rickard from the Auburn Shellfish Laboratory for supplying the oyster shell used in the ReefBLKSM experiments. The geotechnical descriptions of the substrate used in the bagged oyster shell experiments is accredited to Lewis Copeland, Vice President, of Southern Earth Sciences. John Lyon is acknowledged for his fabrication expertise in constructing the ii frames for the ReefBLKSM. Additionally, set up and execution of the physical experiments could not have been accomplished without the support of Timothy Wicker, Drew Harrison, and Caren Reid Dixon.
Finally, the financial and physical support of the author's parents, Rick and Jan Allen, is attributed to the success of this research. iii TABLE OF CONTENTS Page LIST OF TABLES. vi LIST OF FIGURES. ix LIST OF SYMBOLS.
11 Bagged Oyster Shell. 31 Bagged Oyster Shell. 41 Additional Testing Observations. 46 Bagged Oyster Shell.
APPENDIX A: ADDITIONAL FIGURES AND GRAPHS. 71 APPENDIX B: RAW DATA. 124 v LIST OF TABLES Table Page 1. Bagged oyster shell breakwater experimental setup.
Summary of the experimental setup for the concrete pyramids. Summary of experimental setup for ReefBLKsSM. Bagged oyster shell wave transmission coefficients for a RMS incident wave height of 0.30 ft) and a wave period of 1. Bagged oyster shell wave transmission coefficients for a RMS incident wave height of 0.52 ft) and a wave period of 2.
Concrete pyramid measured wave transmission coefficients obtained for the single row configuration as a function of the non- dimensional length and height. Concrete pyramid measured wave transmission coefficients obtained for the offset double row configuration as a function of the non-dimensional length and height. ReefBLKSM measured wave transmission coefficients as a function of the non-dimensional length and height, organized by experiment number .42 vi Appendix A Table Page A1. Single row configuration testing matrix of concrete pyramids.
Offset double row configuration testing matrix of concrete pyramids. Oyster shell substrate properties used in ReefBLKSM units. ReefBLKSM testing matrix .75 Appendix B Table Page B1. Summary of results for bagged oyster shell testing.
Summary of results for single row of concrete pyramids. Summary of results for offset double row of concrete pyramids. Summary of results for ReefBLKSM. Bagged oyster shell breakwater raw data for incident wave heights.
Bagged oyster shell breakwater raw data for incident wave periods. Transmitted wave height of bagged oyster shell breakwater raw experimental data for an incident wave height of 0.30 ft) and a period of 1.34 sec as a function of structure geometry. Transmitted wave period of bagged oyster shell breakwater raw experimental data for an incident wave height of 0.30 ft) and a period of 1.34 sec as a function of structure geometry. Transmitted wave height of bagged oyster shell breakwater raw experimental data for an incident wave height of 0.52 ft) and a period of 2.03 sec as a function of structure geometry.
Transmitted wave period of bagged oyster shell breakwater raw experimental data for an incident wave height of 0.52 ft) and a period of 2.03 sec as a function of structure geometry. Concrete pyramid control average wave properties. Concrete pyramid single row test data average of all gages. Concrete pyramid offset double row experimental test data.
ReefBLKSM raw experimental data for controls. ReefBLKSM raw experimental data of transmitted wave properties .116 viii LIST OF FIGURES Figure Page 1. University of South Alabama wave basin with splitter wall installed and graded beach face in preparation for testing the bagged oyster shell. Completed oyster shell bag having a nominal diameter of 0.
Grain size distribution findings for oyster shell used in the bagged oyster shell breakwater provided by Southern Earth Sciences. Cross-section of the bagged oyster shell breakwater with pertinent variables defined. University of South Alabama wave basin setup for conducting experimental testing of the concrete pyramids. Single row configuration of model concrete pyramids in the University of South Alabama wave basin.
Offset double row configuration of model concrete pyramids in the University of South Alabama wave basin. Cross-sectional diagram of the concrete pyramids showing the dimensional measurements used for analysis. The University of South Alabama wave basin setup for conducting the experimental testing of the ReefBLKSM units. Plan view of the ReefBLKSM breakwater configuration with the crest width measurement defined.
Plan view of model ReefBLKSM with dimensions. Construction of the ReefBLKSM frame with the help of John Lyon using the University of South Alabama fabrication shop. Model ReefBLKSM with netting material installed. Oyster shell being processed through the Chesapeake Bay Oyster Company sorter at the Auburn Shellfish Laboratory.
ReefBLKSM being filled with oyster shell using a vibratory table. Gradation curve of oyster shell used in model ReefBLKSM. Two-wire capacitance gage used for measuring the water surface elevation within a range of 0. Relationship of non-dimensional height, hc/d, versus the measured wave transmission coefficient, Kt, for all unique experiments tested with the bagged oyster shell.
Two-dimensional graph showing the variation of the bagged oyster shell experimental Kt values as a function of the non-dimensional structure height and length. Relationship of the non-dimensional height, hc/d, to wave transmission coefficients, Kt, obtained for the concrete pyramid single row and offset double row configurations. Non-dimensional length, B/Li, versus measured wave transmission coefficients, Kt, for single row configuration of concrete pyramids. Non-dimensional length, B/Li, as a function of measured wave transmission coefficients, Kt, for offset double row configuration of concrete pyramids.
Two-dimensional plot of measured wave transmission coefficients, as a function of the non-dimensional height and length, for concrete pyramids in a single row configuration. Two-dimensional plot of measured wave transmission coefficients, as a function of the non-dimensional height and length, for concrete pyramids in an offset double row configuration. Graph showing the non-dimensional height, hc/d, versus the measured transmission coefficient, Kt, for all tests performed on the ReefBLKSM units. Graph showing the non-dimensional length, B/Li, as a function of the measured transmission coefficient, Kt, for all tests performed on the ReefBLKSM units with respect to each unique wave characteristic.
Two-dimensional plot of the measured wave transmission coefficient, Kt, for the ReefBLKSM units as a function of the non- dimensional length and height. A comparison of measured and predicted transmission coefficients using the predictive equations of Van der Meer et al. (2005) for bagged oyster shell. Graph showing the single row concrete pyramid transmission coefficient results compared to the transmission coefficients obtained using the Van der Meer et al.
One-to-one comparison of measured transmission coefficients to transmission coefficients computed using the Van der Meer et al. (2005) formulae for cases where Hi/Li is greater than 0.04 for the single row concrete pyramids. Graph showing a one-to-one comparison of the measured wave transmission coefficients and the computed wave transmission coefficients using the Van der Meer et al. (2005) formulae for the offset double row configuration of concrete pyramids.
Segmented wave transmission coefficient data for Hi/Li > 0.04 showing a one-to-one agreement with the computed wave transmission coefficients using Van der Meer et al. (2005) formulae for the offset double row configuration of concrete pyramids. Comparison of the experimental wave transmission coefficient with the predicted wave transmission coefficient in a one-to-one graph using modified Armono and Hall (2003) formula. Plot showing the comparison of measured, predicted, and field project wave transmission coefficients, Kt, as a function of non- dimensional height, hc/d, for the ReefBLKSM .60 xi Appendix A Figure Page A1.
ReefBLKSM installed at Coffee Island, Alabama. Construction of Reef Balls to be placed along Alabama shorelines under the American Recovery and Reinvestment Act. Composition of a bagged oyster shell breakwater to be used at Helen Wood Park, Alabama. Concrete pyramids installed at Little Bay, Alabama.
Oyster shell distribution with scale used in the ReefBLKSM construction .74 xii LIST OF SYMBOLS B = Crest width d = Water depth hc = Structure height Hi = Incident wave height Ht = Transmitted wave height Kt = Transmission coefficient, Ht / Hi Ktl = Lower limit transmission coefficient (Van der Meer et al. 2005) Ktu = Upper limit transmission coefficient (Van der Meer et al. 2005) Li = Wave length (Calculated using S.) Rc, F = Breakwater freeboard, hc - d Sop = Wave steepness, Sop = 2πHi / (gT2) T = Wave period tan α = Seaward slope of breakwater ξ = Surf similarity parameter, ξ = tan α / (Sop)0.5 xiii ABSTRACT Allen, Richard J., University of South Alabama, May 2013. Physical Modeling of Wave Transmission for Submerged and Emergent Breakwaters used in Living Shorelines.
Chair of Committee: Dr. Breakwaters used in living shoreline projects are referred to as engineered reefs and are used to modify wave characteristics along estuarine shorelines in such a way as to promote ecological and biological enhancement, with stabilization of the shoreline often an expressed goal. Studies show engineered reefs are a successful alternative to traditional rubble mound breakwaters in the environmental aspect; however, the true success of these structures has not been quantified in terms of wave energy dissipation. Through physical modeling of engineered reefs using the University of South Alabama’s wave basin, much of the engineering design related to wave energy was determined.
The testing included bagged oyster shell breakwaters, apex-truncated square concrete pyramids, and ReefBLKsSM subjected to multiple wave forms and water depths. Results from the testing showed that wave transmission through bagged oyster shell and concrete pyramid devices can mostly be explained using published methodologies. In terms of structure geometry, the non-dimensional height, hc/d, is the primary factor when designing the engineered reefs. The bagged oyster shell and ReefBLKsSM are more effective in attenuating shorter wave lengths while concrete pyramids are more affective in attenuating longer wave lengths.
The dependence of structure performance on wave period is a new finding. xiv INTRODUCTION Shoreline stabilization is prevalent along estuarine shorelines in the United States.
