Bridge owners rely on subjective evaluation of practices for the identification and assessment of design alternatives to improve the service life of highway bridges. Only a few highway bridges have been designed for specific service life criteria. The AASHTO LRFD Bridge Design Specifications contain requirements for strength design and some serviceability checks. However, there are no comprehensive guidelines for service life design of highway bridges. The Second Strategic Highway Research Program (SHRP 2) Report S2-R19A-RW-2: Design Guide for Bridges for Service Life provides the groundwork for establishing recommendations for extending service life and could be useful in developing a process for assuring target service life of various bridge components and elements. However, bridge owners and designers need an AASHTO guide specification to implement the service life bridge design into projects and standards.
The objectives of this research are to develop (1) proposed AASHTO guide specification for service life design of highway bridges and (2) case studies to demonstrate the application of the proposed guide specification.
(1). Conduct a literature review of relevant domestic and international service life design for highway bridges. The domestic review should include research conducted through the NCHRP; Strategic Highway Research Program 2 (SHRP2); FHWA; and other national, state, and pooled-fund sponsored research. The review should cover research findings, existing design guidelines, and owner and industry experience. (2). Synthesize the literature review to identify the knowledge gaps for service life design for highway bridges. These gaps should be addressed in the final product and in the recommended future research as budget permits.(3). Propose a methodology, to be developed and executed in Phase II, to achieve the project objectives. At a minimum, the methodology should consider the following: (a) multiple analysis methods depending on the type of data available and adaptable to future data; (b) deterioration processes and exposure zones (e.g., coastal vs no coastal highway bridges, splash zone, etc.), and loads; (c) appropriate service life target based on functional requirements and bridge elements; (d) selection of alternative designs to achieve the target service life including data requirements; and (e) effectiveness of various design, construction, inspection, and preservation strategies, as well as management practices.(4). Prepare an annotated table of contents for the proposed AASHTO guide specification. Propose case studies to demonstrate the application of proposed methodology and guide specification. (5). Prepare Interim Report No. 1 that documents Tasks 1 through 4 and provides an updated work plan for the remainder of the research no later than 4 months after contract award. The updated plan must describe the process and rationale for the work proposed for Phases II though IV.
PHASE II—Methodology Development
(6). Fully develop and execute the methodology according to the approved Interim Report No.1. (7). Complete a sample section of the guide specification to be selected by NCHRP. This section should be publication ready (i.e., AASHTO-style format) with appropriate level of detail. (8). Prepare Interim Report No. 2 that documents Tasks 6 and 7 and provides an updated work plan for Phases III and IV no later than 8 months after approval of Phase I.
PHASE III—Guide Specification Development
(9). Develop the remaining sections of the guide specification and prepare illustrations (e.g., flowcharts, graphs) with the case studies. The recommended guide specification shall be provided in AASHTO-style format. (10). Prepare Interim Report No. 3 that documents Task 9 and provides an updated work plan for the remainder of the project no later than 9 months after Phase II approval. The updated plan must describe the process and rationale for the work proposed for Phase IV.
PHASE IV—Final Products
(11). Revise the guide specification after consideration of the panel’s review comments. (12). Prepare final deliverables including: (1) a final report that documents the entire research effort; (2) the proposed AASHTO guide specification and case studies; and (3) a stand-alone technical memorandum titled “Implementation of Research Findings and Products.”