TECHNICAL REPORT STANDARD TITLE PAGE 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. FHWA/TX-11/0-6022-2 4. Title and Subtitle 5. Report Date RECOMMENDATIONS FOR DESIGN, CONSTRUCTION, AND September 2011 MAINTENANCE OF BRIDGE APPROACH SLABS Published: May 2012 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Anand J. Puppala, Ekarut Archeewa, Sireesh Saride, Soheil Nazarian Report 0-6022-2 and Laureano Hoyos 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Department of Civil Engineering The University of Texas at Arlington 11. Contract or Grant No. Arlington, Texas 76019 Project 0-6022 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Texas Department of Transportation Technical Report: Research and Technology Implementation Office September 2007–August 2011 P. O. Box 5080 14. Sponsoring Agency Code Austin, Texas 78763-5080 15. Supplementary Notes Project performed in cooperation with the Texas Department of Transportation and the Federal Highway Administration. Project Title: Recommendations for Design, Construction, and Maintenance of Bridge Approach Slabs URL: http://tti.tamu.edu/documents/0-6022-2.pdf 16. Abstract Settlement and heave related movements of bridge approach slabs relative to bridge decks create a bump in the roadway. Several problems arise from these bumps, which include poor riding conditions, potential vehicle damage, loss of vehicle control causing injuries or even casualities, lowered perception of the department’s road works, increased maintenance works, and constant delays to rehabilitate the distressed lanes. All these make this bump problem a major maintenance problem in Texas. Several mitigation methods have been employed, and the results are not always satisfactory. In the present research, two treatment methods are investigated for controlling settlements of approach slabs of new bridge construction. Researchers from UTA and UTEP performed two phases to accomplish these studies. During the first phase, the documented information that covers various methods used so far for approach slab settlement mitigation technologies is compiled and presented. The second and final phase focused on field evaluation studies of deep soil mixing and light weight embankment fill treatment methods in reducing settlements. A few other technologies were also evaluated for reducing settlements of existing bridge approach slabs. Both design and construction specifications of the new methods that provided effective treatments in field conditions are presented. 17. Key Word 18. Distribution Statement Bridge Approach Settlements, Deep Soil Mixing, No restrictions. This document is available to the Expanded Clay Shale, Embankment, Clay public through NTIS: National Technical Information Service Alexandria, Virginia 22312 http://www.ntis.gov 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price Unclassified Unclassified 386 Form DOT F 1700.7 (8-72) RECOMMENDATIONS FOR DESIGN, CONSTRUCTION, AND MAINTENANCE OF BRIDGE APPROACH SLABS by Anand J. Puppala, Ph.D., PE Professor The University of Texas at Arlington Ekarut Archeewa, Ph.D. Former Doctoral Student The University of Texas at Arlington Sireesh Saride, Ph.D. Former Post-Doctoral Fellow The University of Texas at Arlington Laureano Hoyos, Ph.D., PE Associate Professor The University of Texas at Arlington and Soheil Nazarian, Ph.D., PE Professor The University of Texas at El Paso Project 0-6022 Report 0-6022-2 Project Title: Recommendations for Design, Construction, and Maintenance of Bridge Approach Slabs Performed in cooperation with the Texas Department of Transportation and the Federal Highway Administration September 2011 Published: May 2012 The University of Texas at Arlington Arlington, Texas 76019 DISCLAIMER The contents of this report reflect the views of the authors/principal investigators who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the views or policies of the Federal Highway Administration (FHWA) or the Texas Department of Transportation (TxDOT). This report does not constitute a standard, specification, or regulation. The United States Government and the State of Texas do not endorse products or manufacturers. Trade or manufacturers’ names appear here solely because they are considered essential to the object of this report. ACKNOWLEDGMENTS This study was supported by TxDOT under Research Project No. 0-6022. The authors acknowledge the following individuals and companies: Richard Williammee, Jr., Project Director, for his guidance and help. Several project management committee members including David Head, Dr. German Claros, Behman Afsheen, Bernie Holder, Darrell Anglin, Jon Holt, Mark McClelland, Stanley Yin, Taya Retterer, and Mark McDaniel. Graduate students, Raja Yenigalla, Varagorn Pulijan, Minh Le, and Dr. Bhaskar Chittoori for their help with research and report preparation. v TABLE OF CONTENTS LIST OF FIGURES............... ..................................................................................................... XI LIST OF TABLES ................................................................................................................... XXI EXECUTIVE SUMMARY .......................................................................................................... 1 1 INTRODUCTION...................................................................................................................... 3 1.1 GENERAL ...................................................................................................................................... 3 1.2 RESEARCH OBJECTIVES ............................................................................................................... 4 1.3 RESEARCH REPORT ORGANIZATION ............................................................................................ 4 2 LITERATURE REVIEW ......................................................................................................... 7 2.1 INTRODUCTION ............................................................................................................................. 7 2.1 DEFINITION OF THE BUMP AND THE BUMP TOLERANCE .............................................................. 7 2.1.1 Definition of the Bump ............................................................................................................. 7 2.1.2 Bump Tolerances ..................................................................................................................... 8 2.2 MECHANISMS CAUSING THE FORMATION OF THE BUMP ............................................................. 9 2.2.1 Consolidation Settlement of Foundation Soil ........................................................................ 14 2.2.2 Poor Compaction and Consolidation of Backfill Material .................................................... 16 2.2.3 Poor Drainage and Soil Erosion ........................................................................................... 17 2.2.4 Types of Bridge Abutments .................................................................................................... 19 2.2.5 Traffic Volume ....................................................................................................................... 24 2.2.6 Age of the Approach Slab ...................................................................................................... 24 2.2.7 Approach Slab Design ........................................................................................................... 25 2.2.8 Skewness of the Bridge .......................................................................................................... 25 2.2.9 Seasonal Temperature Variations.......................................................................................... 27 2.3 MITIGATION TECHNIQUES FOR APPROACH SETTLEMENTS OF NEW BRIDGES ........................... 29 2.3.1 Improvement of Embankment Foundation Soil ...................................................................... 29 2.3.2 New Foundation Technologies .............................................................................................. 49 2.3.3 Improvement of Approach Embankment/Backfill Material ................................................... 64 2.3.4 Geosynthetic Reinforced Soils (GRS) .................................................................................... 71 2.3.5 Design of Bridge Foundation Systems ................................................................................... 78 2.3.6 Design of Approach Slab ....................................................................................................... 86 2.3.7 Effective Drainage and Erosion Control Methods ................................................................ 95 2.4 MAINTENANCE MEASURES FOR DISTRESSED APPROACH SLABS ............................................ 101 2.4.1 Replacement Method ............................................................................................................ 103 2.4.2 Mud/Slab Jacking ................................................................................................................ 104 2.4.3 Grouting ............................................................................................................................... 105 2.4.4 Other Methods ....................................................................................................................