Construction

2007 ABC Workshop Follow up

Archived: Summary Report

This report details the discussions stemming from the accelerated bridge construction workshop conducted in San Diego, California on October 11, 2007. The focus of the workshop was accelerating bridge construction in moderate-to-high seismic regions, with a particular emphasis on seismic connections. Sponsorship was provided in part by the Federal Highway Administration (FHWA), the California Department of Transportation (Caltrans), the Transportation Research Board (TRB), the National Steel Bridge Alliance (NSBA), and the National Concrete Bridge Council (NCBC).

Background

FHWA has been actively promoting the advantages of accelerated bridge construction (ABC). Proven benefits include minimized traffic disruption, improved work zone safety, and reduced on-site environmental impacts. Related traffic impacts derive from both expedited congestion relief projects and minimized traffic disruption due to reduced on-site highway construction activities. Safety enhancements benefiting the motoring public and highway workers, as well as lessened environmental impacts are directly attributable to limiting in-situ work requirements. For these reasons, European and Asian countries have already embraced the ABC philosophy for many of their urban construction projects.

Working in concert, bridge owners, FHWA, researchers, and industry have developed techniques successfully applied in many states over the past few years. Momentum has been building nationally, fueled in part by successful applications touted in numerous presentations at various conferences, as well as focused meetings and workshops targeting opportunities to advance the state-of-the-art. FHWA and NCBC sponsored an accelerated bridge construction workshop in Reno, Nevada in May 2006. A broad range of issues were presented and debated during that workshop. Additionally, FHWA, the Precast/Prestressed Concrete Institute (PCI), the Precast/Prestressed Concrete Institute Northeast (PCINE), and the National Cooperative Highway Research Program (NCHRP) have been developing guidelines for designers contemplating ABC on projects. While some research has been initiated on connection details for moderate-to-high seismic regions, in general these connections remain a major unresolved issue.

This workshop, focusing on seismic connection details, was conceived during discussions at the inaugural Seismic Accelerated Bridge Construction meeting conducted during the January 2007 86th Annual TRB Meeting. During the meeting, several presentations concluded or implied the need to further address seismic connection detailing before ABC techniques could gain widespread acceptance and application in regions of moderate-to-high seismic activity. Since a considerable portion of the land mass encompassing the United States of America must address seismic loads in bridge designs, the workshop was intentionally not limited to a single state or region, but rather connection detailing in moderate-to-high seismic regions throughout the country.

Purpose

The purpose of the workshop was to assimilate ideas from a broad spectrum of experts focused on connection details to advance ABC applications in moderate-to-high seismic regions. These ideas were roughly categorized as readily implemented, requiring some degree of research, legislative action, or a measure of institutional change (reference Appendix H). A follow-up to this meeting developed a strategic action plan for advancing application of ABC in regions of moderate-to-high seismic activity, which is included in this report. Additional follow-up meetings will focus on future research and resolving implementation issues.

Process

A steering committee was established to coordinate the workshop and follow-up activities. The steering committee included participation from FHWA, Caltrans, TRB, and consulting experts. Current members are tabulated below:

A group of invited academicians, design, construction, and maintenance professionals were assembled representing seismic-prone regions of the United States (reference Appendix A). Prior to arriving at the meeting, each was asked to prepare for the discussion by researching the topic, thereby extending previous related activities in the area of ABC. Specifically, participants were requested to review FHWA's website https://www.fhwa.dot.gov/construction/accelerated/wsaa0601.cfm (.pdf, 2 mb); the information posted at http//www.fhwa.dot.gov/bridge/prefab/pbesreport.cfm from the ABC workshop conducted in Reno, Nevada in May 2006; and the "Guidelines for Accelerated Bridge Construction using Precast/Prestressed Concrete Components" developed by the PCI Northeast Bridge Technical Committee and available for download at http://www.pcine.org.

Program

The workshop commenced with a number of presentations to set the stage for the brainstorming and subsequent breakout session discussions. Welcoming remarks and motivational statements were provided first by Kevin Thompson, followed by remarks from a panel of experts as delineated below. The actual program is included in Appendix B, with brief summaries of each presentation provided in Appendix C.

Following the morning presentations, a brainstorming session was conducted to leverage experiences and expertise of all workshop participants. Any ideas related to ABC were encouraged, including those that may not fit precisely within the confines of the workshop focus on seismic connection detailing (reference Appendix D). Ideas generated were categorized as listed below.

Those that were not specifically related to the workshop goals were captured and recorded for future consideration. The group was then tasked with prioritizing the ideas for further assessment in the breakout sessions. Individuals were provided free rein in assigning priority. Each was given five votes to be cast for five different ideas. The tally from this voting system resulted in rankings from A to D, with "A" being the highest classification and "D" the lowest. Ideas classified as "A" received six or more votes, those denoted as "B" receiving five votes, three or four votes for category "C", and two vote accumulators classified as "D" (reference Appendix E).

The highest priority ideas were parsed between four breakout groups, with each receiving five concepts to further develop, at least one in each priority categorization. Many of the ideas receiving votes were similar in nature. An initial review of the raw ideas led to some pairings before the group tally commenced. Care was taken during this endeavor to the extent possible to avoid jeopardizing brainstorming ideas by arbitrarily lumping with another deemed similar. Several breakout group discussions further combined ideas, reducing the number of outcomes somewhat. Each breakout group included experts from academia, industry, FHWA, and State DOTs (reference Appendix F for a listing of each breakout group). This assemblage of expertise precluded the need to assign specific category ideas to a particular group, ensuring a robust discussion. The breakout session groups were provided a formatted list of questions (reference Appendix G) designed to stimulate and guide their discussion. The intended outcome was an understanding of the associated obstacles and opportunities required to advance the idea. The groups were encouraged to develop their ideas as far as time and energy allowed, even to the point of developing a draft action plan (reference Appendix H for populated issue templates).