The Implementation of Full Depth UHCP Waffle Bridge Deck Panels

APPENDIX A: STRUCTURAL CHARACTERIZATION OF UHPC WAFFLE BRIDGE DECK PANELS AND CONNECTIONS

April 24, 2010

Prepared by
Institute for Transportation
Iowa State University

Sponsored by
Federal Highway Admininstation, Highways for LIFE
Technology Partnerships Program

List of Figures

Figure 1. Plan and cross section details of the proposed UHPC Waffle Deck Bridge in Wapello County
Figure 2. Shear pocket connection details between girder and the waffle deck
Figure 3. Connection details between the central girder and the waffle deck
Figure 4. Connection details between the waffle deck panels
Figure 5. Reinforcement details of the UHPC waffle deck test panels
Figure 6. Construction sequence of the UHPC Waffle deck panel at the precast plant
Figure 7. Schematic of the test setup used for testing of the UHPC Waffle deck panel system
Figure 8. Details of the reinforcement provided in various joints
Figure 9. UHPC joint pour
Figure 10. Schematic of the displacement transducers mounted to the test unit
Figure 11. Location of strain gauges used on the bottom deck reinforcing bars
Figure 12. Location of strain gauges on the top deck reinforcing bars and dowel bars
Figure 13. Measured force-displacement response and peak rebar strain from gauge B3 at the center of the transverse rib TR2 of panel UWP2
Figure 14. Measured strains along the bottom reinforcement of the transverse rib TR2 of panel UWP2
Figure 15. Measured strains along a bottom reinforcement of the panel-to-panel joint
Figure 16. A hairline crack in the UWP2 panel transverse rib TR2 at 21.3 kips
Figure 17. Simplified relationship for UHPC tensile strength variation with the crack width (AFGC 2002)
Figure 18. Measured force-displacement response and peak rebar strain at the center of the joint at the service load
Figure 19. Measured strains along the bottom reinforcement of the joint during the service load test
Figure 20. Measured strains in the bottom reinforcement of the transverse rib (TR2) along the length of panel UWP2 at service load
Figure 21. Measured strains in the bottom reinforcement of the transverse rib (TR2) along the length of panel UWP1 at service load
Figure 22. Measured strains at the center of the panel across the transverse ribs of UWP1 at service load
Figure 23. A hairline crack formed at the center of underside of the transverse joint at 28 kips
Figure 24. The variation of the peak displacement at the center of the joint during the joint fatigue test
Figure 25. The variation of the peak strain in the bottom joint transverse reinforcement during the joint fatigue test
Figure 26. The variation of the crack width in the transverse joint with number of load cycles
Figure 27. Measured responses of the waffle deck system from the static service load tests conducted during the joint fatigue test
Figure 28. Measured force–displacement response and peak rebar strain at the center of the joint at the ultimate load of 48 kips
Figure 29. Measured strains in the bottom reinforcement of transverse rib TR2 along the length of Panel UWP2 at the ultimate load
Figure 30. Measured strains in the bottom reinforcement of transverse rib TR2 along the length of Panel UWP1 at the ultimate load
Figure 31. Measured strains at the center of the panel across the transverse ribs of panel UWP1at joint ultimate load
Figure 32. Hairline cracks formed at the center of underside of the transverse joint at the ultimate load of 48 kips
Figure 33. The variation in the width of the most critical crack in the ribs forming the transverse joint
Figure 34. The peak displacement variation at the center of Panel UWP1 during the joint fatigue test
Figure 35. The peak strain variation in bottom deck reinforcement in the transverse rib of UWP1and the joint during panel fatigue test
Figure 36. The crack width variation in transverse rib TR2 of panel UWP1 during panel fatigue test
Figure 37. Measured responses of the waffle deck system for static service load tests conducted during the panel fatigue test
Figure 38. Measured force–displacement response and peak rebar strain at the center of the transverse rib of UWP1 at the ultimate load of 40 kips
Figure 39. Measured strains in the bottom reinforcement of the transverse rib along the length of UWP1 at during the ultimate load test
Figure 40. Measured strains in the bottom reinforcement of the joint along the joint length during the ultimate load test
Figure 41. Hairline cracks developed on panel UWP1 at an ultimate load of 40 kips
Figure 42. Measured crack width in transverse rib TR2 of UWP1 at during the ultimate load test
Figure 43. Strain variations in a dowel bar placed in the panel–to–girder joint during the panel ultimate load test

List of Tables

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Technical Report Documentation Page
1. Report No.	2. Government Accession No.	3. Recipient's Catalog No.
4. Title and Subtitle Structural Characterization of UHPC Waffle Bridge Deck Panels and Connections		5. Report Date April 2010
		6. Performing Organization Code
7. Author(s) Sriram Aaleti, Sri Sritharan, Matt Rouse and Terry Wipf		8. Performing Organization Report No.
9. Performing Organization Name and Address Institute for Transportation Iowa State University 2711 South Loop Drive, Suite 4700 Ames, IA 50010–8664		10. Work Unit No.(TRAIS)
		11. Contract or Grant No.
12. Sponsoring Agency Name and Address Iowa Highway Research Board Iowa Department of Transportation 800 Lincoln Way Ames, IA 50010		13. Type of Report and Period Covered Phase 1 Report
		14. Sponsoring Agency Code
15. Supplementary Notes Visit www.intrans.iastate.edu for color PDF files of this and other research reports.
16. Abstract The AASHTO strategic plan in 2005 for bridge engineering identified extending the service life of bridges and accelerating bridge construction as two of the grand challenges in bridge engineering, with the objective of producing safer and economical bridges at a faster rate that have a minimum service life of 75 years and reduced maintenance cost to cater the country's infrastructure needs. Previous studies has shown that a prefabricated full–depth precast concrete deck system is an innovative technique that accelerates the rehabilitation process of a bridge deck extending its service life with reduced user delays, and community disruptions and lowering its life–cycle costs. Previous use of Ultra high performance concrete (UHPC) for bridge applications in the United States have been proven to be efficient and economical due to its superior structural characteristics and durability. The design of full depth UHPC waffle deck panel systems have been developed over the past three years in Europe and the U.S. A full–scale, single span 60 ft long and 33 ft wide prototype bridge with full depth prefabricated UHPC waffle deck panels has been planned for a replacement bridge in Wapello County, Iowa. The structural performance characteristics and the constructability of the UHPC waffle deck system and its critical connections were studied through an experimental program at the structural laboratory of Iowa State University (ISU). Two prefabricated, full–depth, UHPC waffle deck (8ft x 9ft 9 inches x 8 inches) panels were connected to 24–ft long precast girders and the system was tested under service, fatigue and ultimate loads. Based on the test results, test observations and the experience gained from the sequence of construction events such as fabrication, casting of transverse and longitudinal joints, a prefabricated UHPC Waffle deck system is found to be a viable option to achieve the goals of AASHTO strategic plan.
17. Key Words Waffle deck panels–ultra high performance concrete (UHPC) – precast – uhpc joints		18. Distribution Statement No restrictions.
19. Security Classif. (of this page) Unclassified	20. No. of Pages	21. Price	NA

Abstract

The authors want to acknowledge and thank all the help provided by the undergraduate lab assistants Andrew Barone and Owen Stiffens with the test setup and testing of the waffle deck system. The help and guidance provided by Doug Wood, structural lab manager at Iowa State University in completing the tests in a tight schedule is greatly appreciated.

The AASHTO strategic plan in 2005 for bridge engineering identified extending the service life of bridges and accelerating bridge construction as two of the grand challenges in bridge engineering, with the objective of producing safer and economical bridges at a faster rate that have a minimum service life of 75 years and reduced maintenance cost to cater the country's infrastructure needs. Previous studies has shown that a prefabricated full–depth precast concrete deck system is an innovative technique that accelerates the rehabilitation process of a bridge deck extending its service life with reduced user delays, and community disruptions and lowering its life–cycle costs. Previous use of Ultra high performance concrete (UHPC) for bridge applications in the United States have been proven to be efficient and economical due to its superior structural characteristics and durability.

Acknowledgement

The authors would like to thank the Coreslab Structures of Omaha and Iowa Highway Research Board for sponsoring this research project. The authors would also like to thank Kyle Nachuk from Lafarge North America for providing technical assistance with the UHPC mixing and help with casting of joints in the test specimen. We would like to thank John Heimann from the Coreslab Structures of Omaha for helping and organizing the casting of the waffle deck panels in a timely manner.

The following individuals served on the Technical Advisory Committee of this research project: Ahmad Abu–Hawash, Dean Bierwagen, Brian Moore, Mark Dunn, Norman McDonald, Wayne Sunday, Kenneth Dunker and Ping Lu. Their guidance and feedback during the course of the project are also greatly appreciated. We also appreciate the feedback and review comments given by Julie Zirlin and Benjamin Graybeal of FHWA on the draft version of this report.

Introduction

Today there are over 160,000 bridges in the nation that are structurally deficient or obsolete with more than 3,000 new bridges added to this list each year (Bhide 2001). Many bridges are subjected to weights, loads, and traffic volumes exceeding limits of their original design while current bridge inspection methods do not detect all structural problems encountered in the field. Deterioration of the bridge deck is a leading cause for the obsolete and/or deficient inspection rating of the bridges (http://www.zellcomp.com/infrastructure_crisis.html, Stantill-McMcillan and Hatfield 1994). Federal, State and municipal bridge engineers are seeking alternative ways to build better bridges, reduce travel times, and improve repair techniques, thereby reducing maintenance costs of bridge infrastructure. Additionally, owners are challenged with replacing critical bridge components, particularly rapidly deteriorating bridge decks, during limited or overnight road closure periods. Therefore, there is an impending need to develop and use longer-lasting materials and innovative technologies to accomplish safe and fast construction of high quality bridges and highways.

To overcome the nation's aging bridge infrastructure requires development of cost efficient, widely applicable, and long–lasting bridge elements and systems and accelerated bridge construction techniques. To increase longevity and reduce maintenance costs, the potential use of ultra–high performance concrete (UHPC) in bridges is gaining significant interest amongst several State Departments of Transportations (DOTs) and the Federal Highway Administration (FHWA). The use of full depth precast deck panels in bridges is not new, nor is the use of UHPC as deck panel joint fill. Several U.S. State and Canadian Provincial DOT's have explored the use of full depth precast deck panels in bridges. UHPC has also been used as joint fill material by the Ontario Ministry of Transportation on full depth solid deck panels made from High Performance Concrete (Perry et al. 2007). In support of reducing the aging bridge infrastructure stock in the U.S., innovative use of UHPC in bridge applications has been underway for the past several years. The State of Iowa has been in the forefront of this mission with implementations of the first UHPC bulb–tee and Pi girders in bridges and development of an H–shaped UHPC precast pile for foundation application (Vande Voort et al. 2007; Keierleber et al. 2007, Sritharan 2009). The interest in using UHPC for highway bridge decks has been ongoing in the U.S. since the year 2000. Research and Development (R&D) at the FHWA Turner Fairbanks facility commenced in 2000 and prototype bridge decks utilizing UHPC have been under development since that time. Various types of UHPC precast deck systems have been prototyped during this period. However, to date, there are no UHPC precast deck panels in service in our highway system.

The design of full depth UHPC waffle deck panel systems have been developed over the past three years in Europe and the U.S. The FHWA explored this system and published a Techbrief on this topic (FHWA 2007). Significant research and development, analysis, design, and prototyping of separate components of this innovation have also been explored (i.e., joint, shear, key, skid resistance, durability, etc.) (Perry et al. 2007). Nevertheless, these innovations have not been installed in the U.S. highway system. State DOTs from Virginia, Florida, Iowa and New York have expressed interest in utilizing UHPC waffle deck panel system if the performance of the system is proven satisfactory through experimental testing. The main reason for the broad interest in the UHPC waffle deck panel is that this concept is applicable for both new bridges as well as for rehabilitation of existing deteriorated bridge decks.

The first application of the full depth UHPC waffle deck panel has been planned for a replacement bridge in Wapello County, Iowa. With the deck panels designed specifically for this project, the validation of the assumed structural performance characteristics of the UHPC waffle deck, critical connections, system performance, and rideability of the panel surface were performed through an experimental program at the structural laboratory of Iowa State University (ISU). For this project, two prefabricated, full–depth, UHPC waffle deck (8ft x 9ft 9 inches x 8 inches) panels were connected to 24–ft long precast girders and the system was tested under service, fatigue and ultimate loads. In addition, the response of the system was evaluated using a detailed 3D finite element model. The results from this investigation and recommendations for using these panels in the Wapello County bridge project are presented in this report.