Click for next page ( 3

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement

Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 2
2 CHAPTER 1 Background Statement of the Problem zones is necessary to provide the benefits of ABC for all high- way users. The FHWA and many state DOTs are actively promot- ing accelerated bridge construction (ABC) to minimize construction-related impacts to the traveling public and to Objectives of the Study enhance work-zone safety. Many successful applications of The scope of the study was generally determined by the tasks ABC techniques have been recently realized, largely in regions identified in the request for proposal (RFP). The following is of low seismic activity. A number of these ABC applications the task description from the RFP: are documented in Connection Details for Prefabricated Elements and Systems, published by FHWA in 2009. The objective of this research is to synthesize the available However, use of ABC techniques has been more limited in information related to connection details recently used or under moderate-to-high seismic regions of the country. A key factor development for potential use on ABC bridges with promise for more widespread application in seismic regions. The work should in successful implementation of this initiative lies in the con- include the following connection categories, and associated com- nections between prefabricated elements. Providing reliable ponents and systems: connections to ensure ductile performance is essential to Pile to pile cap connections developing designs capable of performing to the specifications Foundation to substructure connections required in earthquake-prone areas. Several prefabricated con- Substructure to superstructure joints and connections Connections between column segments nection details used for recent ABC projects in seismic regions Connection between precast girders and pier diaphragms hold significant promise for more widespread application, but Various connection devices and technologies they have not been fully tested for seismic loading. In addition, Superstructure to substructure connection from Self-Propelled by testing these details and developing an improved under- Modular Transporters (SPMTs) (Roll-in) technology standing of their ultimate performance, these details could be It is anticipated that the research will encompass at least the following tasks. used for potential ABC application throughout the country for Task 1. Review relevant literature, specifications, ongoing other extreme event hazards. research findings, current practices and other information can- The challenge of ABC construction in seismic regions affects vassing all engineering and material disciplines to determine at least 36 of the 50 U.S. states, according to the American the current state of knowledge on connections, and associated Association of State Highway and Transportation Officials components and systems for potential research in each above- (AASHTO) seismic design methodology, which is a function mentioned connection category. This information shall be assem- bled from published and unpublished reports, contacts with of site soil conditions. For sites with the poorest soils, 36 states academia, transportation agencies, industry organizations, and could have bridges that fall into the moderate-to-high seismic other domestic and foreign sources, bridge owners, precast fabri- areas (Seismic Zone 2 or higher and Seismic Design Category cators, contractors, and others. of B or higher). Therefore, this is a national issue. The sys- Task 2. Summarize the various connections and joints iden- tems developed in this research will, of course, be usable in tified on Task 1. Outline the perceived advantages and disadvan- tages of each respective detail based on constructability, seismic all 50 states. If the connections' constructability properties are performance, inspectability, and durability. In addition each outstanding, their use may be economically attractive, even if connection and joint should be assessed for its effect on system high connection ductility is not required. The use of ABC is a performance. national initiative and expansion of the use of ABC to seismic Task 3. Identify gaps in validation of the findings in Task 2.