Bridges for Service Life Beyond 100 Years: Innovative Systems, Subsystems, and Components (2014)

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5C h a p t e r 2 This chapter outlines the efforts, steps, and approaches used to fulfill the project objectives. To accomplish the final goals of Project R19A, tasks were divided into Phase 1 and Phase 2. During Phase 1, steps were taken to identify specific problems, comprehend the cur- rent state of the practice, and locate technological gaps. The outcome of Phase 1 was a scope of work intended to address a select number of the identified technological gaps and develop an outline of a methodology that could lead to the design of bridges for service life. Phase 2 consisted of con- ducting the scope of work that had been identified in Phase 1 and developing a methodology for designing bridges for ser- vice life. The following sections briefly describe the efforts leading to identifying the bridge service life issues. Department of transportation Surveys The R19A project conducted a comprehensive survey in early 2008; results are provided in Chapter 3. About a year later, a related SHRP 2 project, R19B (Bridges for Service Life Beyond 100 Years: Service Limit State Design), conducted a shorter survey. Figure 2.1 shows the 20 states that responded to the R19A survey and 15 states that responded to the R19B proj- ect. Combined, the two surveys covered a large portion of the United States, as well as the province of Ontario, Canada. The objective of the Federal Highway Administration (FHWA) Long-Term Bridge Performance Program (LTBP) is to compile quantitative information from bridges nation- wide. The R19A research team initiated communication with the LTBP as early as 2008. Within the LTBP, a number of states were interviewed to identify problematic issues that prevent bridges from achieving long service life. Figure 2.2 shows the states that were interviewed by the LTBP and states that responded to the R19A survey. The LTBP interviewed several states that did not respond to the R19A survey. aspects of r19B Survey results related to r19a Scope of Work The following excerpt from the R19B survey indicates the ser- vice life problematic areas: The survey responses indicate that there are many service- ability issues relating to expansion joints and deck cracking. The other responses include: deterioration/section loss of beam ends, painting of steel members, problems with bear- ings, corrosion of reinforcement, and deck overlays. Figure 2.3 illustrates the responses to the first question in the R19B survey. Summary of Consultant Survey results After submission of the Phase 1 report and while the research team was waiting to receive review comments, one additional survey was carried out by the R19A research team that sought input from design consulting firms HDR, Inc. and Atkins (previously PBS&J), which subcontracted to the R19A proj- ect. Figure 2.4 shows the locations where these two firms have local offices. The survey focused on gathering the experience of HDR, Inc. and Atkins bridge professionals with respect to bridge durability in the states where they provide services. A series of questions was asked of multiple HDR, Inc. and Atkins offices representing states across the country regard- ing their experience with local bridge durability and service life issues. Questions were asked regarding service life and maintenance requirements for bridge systems, subsystems, and components. Combined responses were received from bridge personnel representing Arizona, California, Colorado, Florida, Illinois, Missouri, Massachusetts, Nevada, North Carolina, Nebraska, Ohio, and Pennsylvania. Research Approach

6Bridge System Service Life and Durability The first series of questions dealt with what common steel or concrete bridge system (such as steel girder, steel truss, prestressed concrete girder) is the most problematic regard- ing service life and typically requires the highest level of maintenance. The predominant answers were painted steel trusses and steel girders. Other responses included concrete or steel bridges with deck joints, posttensioned segmental girders in aggressive environments, and concrete spalling. Some respondents noted that all systems require some form of maintenance. • Reasons for these situations—Major reasons for system ser- vice life reduction and maintenance were steel corrosion due to deicing chemicals or saltwater environment, paint system failures and need for cleaning, corrosion of rein- forcing steel, leaking deck joints, and fatigue. • Potential needed research—Responses included improved coating systems and noncorrosive deicing materials. (a) (b) Figure 2.1. States that responded to the (a) R19A and (b) R19B surveys. (a) (b) Figure 2.2. States that responded to the (a) R19A and (b) LTBP surveys.

7• Systems that have performed the best—Most respondents listed prestressed concrete girder systems, particularly prestressed I-girders and nonskewed prestressed girders. Others mentioned continuous systems without joints and weathering steel girder systems. Bridge Subsystem Service Life and Durability The second series of questions dealt with what subsystem (such as decks, piers, abutments) is the most problematic regarding service life and typically requires the highest level of maintenance. Concrete decks were by far the most predominant answer. Other answers included areas below open joints, substruc- ture, and hinges in continuous box girder bridges. • Reasons for these situations—Reasons for deck service life issues were environmental effects, moisture, chlorides, corrosion of reinforcing steel, material quality and con- struction issues, higher traffic and loads, and cracking. • Potential needed research—Many areas of potential research were noted, including improved materials (high- performance concrete) and details, improved reinforcing Figure 2.3. Responses to SHRP 2 R19B Survey Question 1. Figure 2.4. U.S. map with locations of branch offices for HDR, Inc., and Atkins.

8steel protection, improved deck preservation systems, improved joint details, and effective concrete curing. • Subsystems that have performed the best—For decks, the res pondents identified the best performers as cast-in- place decks with adequate reinforcing bar cover, cast-in- place decks with burlap curing and strict enforcement of temperature gradient during pouring, high-quality con- crete and quality control methods, and properly constructed latex-modified concrete– or microsilica-modified concrete– overlaid decks. Other responses included integral bridges and piers and abutments when joints are eliminated. Bridge Component Service Life and Durability The third series of questions asked what common bridge com- ponents (such as a bearing type, sliding surface in bearings, expansion joint type, joints in approach slab, and so forth) are the most problematic regarding service life and typically require the highest level of maintenance. Deck expansion joints, including strip seals, compression seals, modular joints, and joints of all types were the predom- inant response. Problems with bearings, especially older steel rocker types, were also listed frequently. Additional responses included joint seals and bearings in skewed bridges and prob- lems with hinges. • Reasons for these situations—Reasons for joint failure were environmental and traffic distresses, plow damage, material failure, adhesive failure, improper installation, lack of main- tenance, and distortion due to skew. Freezing of steel rocker bearings was the greatest reason for bearing problems. • Potential needed research—Areas listed for potential research included improved joint systems and materials, longer jointless systems and methods for eliminating joints, ana- lytical studies on effects of skew on joint and bearing move- ment, and joint systems that work with skews. Research areas for bearings included improved bearing details and further studies of reinforced elastomeric bearings, sliding surfaces, and disk bearings. • Components that have performed the best—Eliminating joints and the use of integral and semi-integral abutments were the greatest responses. Nonskewed bridges were also mentioned. Of the joint types, strip seal joints were identi- fied as performing the best for shorter movements. Steel- reinforced elastomeric bearings were identified as the best bearing performer. Disk bearings also were mentioned. Input from Long-term Bridge performance program Starting in 2008, R19A team members established communi- cation with the LTBP project, led by Rutgers University, and held a number of meetings at FHWA headquarters, during which a summary of R19A activities, research direction, and survey results were presented and the importance of collabo- ration was emphasized. Input from aaShtO Bridge Committees Throughout the project, the research team received feed- back from various American Association of State Highway and Transportation Officials (AASHTO) bridge committees through presentations at the committee meetings and phone conferences. Table 2.1 summarizes some of the major activi- ties related to communication with AASHTO bridge techni- cal committees during Phase 1 of the project. Throughout Table 2.1. Summary of Communications with AASHTO Bridge Subcommittees Date Activity Participants February 2008 Presentations to AASHTO T-14 Committee on Steel Bridges R19A research team April 2008 Presentation to AASHTO T-10 Committee on Concrete Bridges R19A research team January 2009 Presentation to AASHTO T-5 on R19A’s activities during 2009 TRB annual meeting R19A research team February 2009 Joint meeting in Orlando, Fla., with AASHTO T-14 and AISI Steel Bridge Task Force R19A research team July 2009 Presentation to AASHTO T-2 Committee on Bearings and Expansion Devices Atorod Azizinamini and Ed Power July 2009 Presentation to AASHTO T-9 Committee on Bridge Preservation Atorod Azizinamini July 2009 Presentation to AASHTO T-10 Committee on Concrete Design Glenn Myers July 2009 Presentation to AASHTO T-14 Committee on Steel Bridges Ed Power and Dennis Mertz July 2009 Presentation to AASHTO SCOBS general session Atorod Azizinamini Throughout Phase 1 Several phone seminars with various state bridge engineers R19A research team Note: SCOBS = Subcommittee on Bridges and Structures.

9the project, various presentations were made during every AASHTO bridge subcommittee meeting. Input from experts Outside the r19a research team Several individuals with expertise related to the R19A research theme were identified, and meetings and phone conferences were held to acquire their input. Table 2.2 briefly summarizes some of the major activities related to these communications during Phase 1 meetings. Additional meetings beyond those listed in Table 2.2 were also held during Phases 1 and 2. Input from Industry Several companies were contacted to acquire their input and viewpoints, including companies involved with expansion joints and bearing manufacturing, various reinforcing bar manufacturers, and a representative from the coating industry. Literature Search A comprehensive literature search identified available infor- mation worldwide. Published, unpublished, and ongoing research projects were examined to better comprehend the state of knowledge. phase 1 Major Findings The results of Phase 1 activities, which revealed the need for the development of a systematic approach for design for service life, were used to develop a scope of work for Phase 2 of the investigation. The major conclusion from the Phase 1 study was that there was a need to develop a stand-alone document that was com- prehensive, coherent, transparent, and devoted to design of bridges for service life—a document that could be used by the bridge community to design new and existing bridges for service life in a systematic manner. Therefore, it was decided to develop such a stand-alone document. This document became the Design Guide for Bridges for Service Life (the Guide). Figure 2.5 summarizes the various activities leading to development of the Guide. Identifying the problematic issues causing service life problems was the first undertaking. Several tasks, including department of transportation (DOT) surveys and input from the industry, were performed to gather this information. The results of many activities, listed in the Prob- lematic Issues box shown in Figure 2.5, led to the establish- ment of problems needing considerations during design for service life of bridges. As noted in Figure 2.5, the problematic issues identified through the various listed tasks fell into several major catego- ries. Within each category, various problems needing research to fill the knowledge gap were identified. The project resources were limited, preventing research into all the identified prob- lems, and priority had to be established. Technology, strategy, and ranking tables were developed as part of the decision- making process for streamlining and identifying the research topics and ranking their priority. Technology, strategy, and ranking tables were used to divide the selected research topics into three categories, as shown in the Suggested Topics block of Figure 2.5. Within the scope of this project, research studies were carried out on higher- priority topics (Categories 1 and 2). Category 3 research top- ics were left for others to complete. Because of the limited resources and as part of the project requirements, the scope of work for research studies carried out for Category 1 and 2 top- ics was limited to proof of concept tests, signifying that addi- tional work would be needed before the concepts are used in practice. The level of investigation conducted on Category 1 was generally greater than that conducted for Category 2. Chapter 3 lists the Category 1 and 2 research topics investi- gated within the R19A project, and Category 3 research topics are described in Appendix A. Results of research studies conducted on Category 1 and 2 topics are included in the Guide. However, the new concepts, details, and design provisions were placed in appendices of the Guide, signifying that they should be used with caution until such time as more research has been conducted. Table 2.2. Summary of Communications with Experts Outside the Research Team: Phase 1 Date Activity Participants April 2008 Phone seminars on bridge deck and concrete durability with David Darwin (University of Kansas) R19A research team, SHRP 2 program officer, ad hoc committee, and David Darwin May 2008 Phone seminars on bearing design with Charles Roeder (University of Washington) R19A research team, ad hoc committee, and Charles Roeder May 2008 Phone seminars on durability of steel bridges with John Fisher (Lehigh University) R19A research team and John Fisher May 2008 Phone seminars on joint durability with Cathy French (University of Minnesota) R19A research team and Cathy French

10 Guide: Project Main Product Information summarized in the Guide was obtained through many activities and resources, including • Results of research studies conducted on Category 1 and 2 research topics; • Available information from the AASHTO LRFD Bridge Design Specifications (AASHTO 2004, 2010b) and AASHTO LRFD Bridge Construction Specifications (AASHTO 2010a); • Research results developed by other investigations; • Synthesis of state-of-the-art information related to various topics covered by the Guide; and • Input from AASHTO bridge subcommittees, DOTs, indus- try, and nonprofit organizations representing various industries. The Guide is a stand-alone document and contains the summary findings of the entire project related to service life design. The use of the Guide was originally intended for bridges with maximum span lengths of 300 ft or less. However, the general framework developed for design for service life and described in Chapter 1 of the Guide is applicable to any span length and bridge type. With permission of the SHRP 2 program officer, the first use of the Guide was in the form of a brief summary of Chap- ter 1 that was provided to short-listed consultants on the new Tappan Zee Bridge in New York in 2012. Through a series of meetings and presentations, the New York Thruway Author- ity and New York DOT decided to make the brief summary of the Guide available to the consultants as a reference for service life design of bridges. Major Categories Suggested Topics Problematic Issues Stand Alone Guide Strategy, Technology and Ranking Tables Concrete Durability Bridge Decks Substructures Bearings Fatigue and Fracture Steel Bridges Expansion Joints, Joints and Jointless Structural Steel Protection Concrete Bridges Ca teg or y 1 Ca teg or y 2 Ca teg or y 3 Input of AASHTO Sub-committeesSurvey of DOTs Input from IndustryInput of Individuals Outside the Team Analysis of NBI Data Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Start AASHTO Specifications Figure 2.5. Overall project activities.