FULL-SCALE WIND LOADING ON GREEN ROOF SYSTEMS By TUAN D. VO A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ENGINEERING UNIVERSITY OF FLORIDA 2013 1 © 2013 Tuan D. Vo 2 To my parents, Duc and Chin, for always believing in me 3 ACKNOWLEDGMENTS I would like to thank the Florida Building Commission’s (FBC) Hurricane Research Advisory Committee (HRAC), the Florida Department of Emergency Management (FDEM), Kurt Fischer of Weston Solutions, and Nathan Griswold of American Hydrotech for providing the necessary funding and materials required for the completion of this project. I would also like to thank my advisor David O. Prevatt, Ph. D., and my committee members, Forrest Masters, Ph. D., and Glenn A. Acomb, FASLA, for their support and guidance throughout this project. Finally, I want to thank my mentors, colleagues, and co-workers: Scott Bolton, Nick Schild, Alon Krauthammer, Jeandona Doreste, David Roueche, Alex Esposito, Abraham Alende, Walter Lindon, Duzgun Agdas, Ph. D., Mark Clark, Ph. D., Aaron Weiner, Craig Dixon, Scott-Foss Kilburn, Ashlie Kerr, Barrett Mooney, and James Austin for their unprecedented aid and assistance throughout the progression of this project. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 9 LIST OF FIGURES ........................................................................................................ 11 LIST OF ABBREVIATIONS ........................................................................................... 18 ABSTRACT ................................................................................................................... 20 CHAPTER 1 INTRODUCTION .................................................................................................... 22 Current Industry Issues with Green Roof Wind Loads ............................................ 22 Scope of Research ................................................................................................. 26 Organization of this Document ................................................................................ 27 2 LITERATURE REVIEW FOR WIND EFFECTS ON GREEN ROOF SYSTEMS ..... 29 Post-Storm Wind Performance Case Studies on Green Roof Systems .................. 29 Successful Post-Storm Performance of Green Roof Systems .......................... 29 2004 – Bonita Bay green roof in Ft. Myers, Florida .................................... 29 2008 – Three intensive garden roofs in Downtown Houston, Texas .......... 30 2008 – Intensive built-in-place green roof in Webster, Texas .................... 32 Reported Green Roof Damage due to Wind ..................................................... 33 1999 – Catastrophic failure of an extensive green roof, Germany ............. 33 2012 – Green roof wind damage in the Midwest United States ................. 34 Discussion ........................................................................................................ 36 Wind-Related Studies on Green Roof Systems ...................................................... 36 1999 – WSP Engineering, Aachen, Germany .................................................. 37 2009 – Southern Illinois University Edwardsville, Illinois .................................. 39 2010 – University of Florida, Gainesville, Florida ............................................. 41 2011 – University of Central Florida, Orlando, Florida ...................................... 43 2012 – LiveRoof WindDisc™ chamber uplift testing ......................................... 45 Summary .......................................................................................................... 48 Discussion ........................................................................................................ 49 Green Roof Wind Design Guidelines and Standards .............................................. 49 FLL ................................................................................................................... 50 FM 1-35 ............................................................................................................ 53 ANSI/SPRI RP-14 ............................................................................................ 54 Summary .......................................................................................................... 56 Discussion ........................................................................................................ 56 Review of Indirect Wind Studies Related to Green Roofs ....................................... 57 5 Wind effects on vegetation at ground level ....................................................... 57 Blow-off of embedded roof gravel ..................................................................... 59 Scour of embedded roof gravel ........................................................................ 61 Roof paver uplift and blow-off ........................................................................... 62 Summary .......................................................................................................... 64 Discussion ........................................................................................................ 65 Summary and Comparison ..................................................................................... 65 3 GREEN ROOF WIND TESTING WITH UF’S HURRICANE SIMULATOR .............. 67 Objective ................................................................................................................. 67 Description of Hurricane Simulator ......................................................................... 67 Plant Selection ........................................................................................................ 69 Phase 1 Materials and Methods ............................................................................. 70 Preparation of Green Roof Modules ................................................................. 71 Description of Test Structure ............................................................................ 73 Instrumentation and Data Acquisition Methods ................................................ 74 Wind speed monitoring .............................................................................. 74 Visual assessment ..................................................................................... 74 Pre- and post-test weight measurement .................................................... 75 Test Procedure ................................................................................................. 76 Phase 2 Materials and Methods ............................................................................. 77 Preparation of Green Roof Modules ................................................................. 78 Construction and Preparation of Built-in-Place Green Roof Assemblies .......... 78 Description of Test Structure and Test Site ...................................................... 80 Instrumentation and Data Acquisition ............................................................... 82 Wind speed monitoring .............................................................................. 82 Pre- and post-test weight measurement .................................................... 82 Visual assessment ..................................................................................... 83 Growth media moisture content ................................................................. 83 Test Procedure ................................................................................................. 84 Results and Discussion........................................................................................... 87 Phase 1 Wind Testing ...................................................................................... 88 Variation in plant heights ............................................................................ 88 Parapet effects ........................................................................................... 89 Plant performance ...................................................................................... 91 Phase 2 Wind Testing ...................................................................................... 96 Green roof module blow-off failures ........................................................... 96 Variation in establishment length and system type .................................... 98 Growth media erosion patterns in built-in-place green roof systems ........ 102 Vegetation sheltering effect on loose aggregate ...................................... 103 Varying test durations .............................................................................. 104 Growth media moisture content effects .................................................... 113 Variation in plant heights .......................................................................... 114 Variation in module depths....................................................................... 115 Vegetation damage .................................................................................. 115 Statistical Analyses ........................................................................................ 116 6 Summary 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