VERMONT AGENCY OF TRANSPORTATION Research and Development Section Research Report ASSESSMENT OF THE “BRIDGE IN A BACKPACK” BRIDGE SYSTEM FROM ADVANCED INFRASTRUCTURE TECHNOLOGIES (AIT) Report 2014 – 12 December 2014 ASSESSMENT OF THE “BRIDGE IN A BACKPACK” BRIDGE SYSTEM FROM ADVANCED INFRASTRUCTURE TECHNOLOGIES (AIT) Report 2014 – 12 DECEMBER 2014 Reporting on Public Information Finding 2013-PIF-01 STATE OF VERMONT AGENCY OF TRANSPORTATION RESEARCH & DEVELOPMENT SECTION BRIAN R. SEARLES, SECRETARY OF TRANSPORTATION CHRIS COLE, DIRECTOR OF POLICY, PLANNING AND INTERMODAL DEVELOPMENT JOE SEGALE, P.E./PTP, PLANNING, POLICY & RESEARCH WILLIAM E. AHEARN, P.E., RESEARCH & DEVELOPMENT Prepared By: George W. Colgrove III, Research Administrator Reviewed By: William E. Ahearn, P.E., Research & Development Engineer Date: December 9, 2014 The information contained in this report was compiled for the use of the Vermont Agency of Transportation (VTrans). Conclusions and recommendations contained herein are based upon the research data obtained and the expertise of the researchers, and are not necessarily to be construed as Agency policy. This report does not constitute a standard, specification, or regulation. VTrans assumes no liability for its contents or the use thereof. II Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. 2014-12 - - - - - - 4. Title and Subtitle 5. Report Date ASSESSMENT OF THE “BRIDGE IN A BACKPACK” BRIDGE DECEMBER 2014 SYSTEM FROM ADVANCED INFRASTRUCTURE 6. Performing Organization Code TECHNOLOGIES (AIT) 7. Author(s) 8. Performing Organization Report No. George W. Colgrove III 2014-12 9. Performing Organization Name and Address 10. Work Unit No. Vermont Agency of Transportation 11. Contract or Grant No. Research & Development Section 1 National Life Drive National Life Building 2013-PIF-01 Montpelier, VT 05633-5001 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Federal Highway Administration Initial Division Office 2013 - 2014 Federal Building 14. Sponsoring Agency Code Montpelier, VT 05602 15. Supplementary Notes 16. Abstract The Vermont Agency of Transportation (VTrans) installed a Bridge in a Backpack (BiaB) system, or also referred to as a Rigified FRP Tube Arch (RFTA) Structure on a low volume road in a rural setting. The value of using this system is the potential to use smaller and lighter construction equipment for a restricted delivery location such as forest or farm roads. The BiaB does not require large cranes and there is a potential for in-field fabrication of the tube arch members where large truck delivery is limited. Advantages of the system include good waterway characteristics and suitability for ledge controlled or spread footings. Disadvantages of the system are that few have been constructed and that it has aesthetic limitations. The construction of the Fairfield BiaB project proceeded smoothly. Generally, site conditions and limited experience with the BiaB led to less than ideal means and methods for construction of the system. During construction, it was noted that several opportunities remain for further expedited construction and cost reduction. Generally, VTrans’ experience with the BiaB showed that the system provides a benefit to the State. 17. Key Words 18. Distribution Statement Bridge in a Backpack, BiaB, FRP Tubes, Composite Arch Bridge System, CABS, No Restrictions. Rigified FRP Tube Arch, RFTA 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. Pages 22. Price - - - - - - - - - Form DOT F1700.7 (8-72) Reproduction of completed pages authorized III TABLE OF CONTENTS Abstract ........................................................................................................................................... 1 Introduction ..................................................................................................................................... 2 Project Location and Summary ....................................................................................................... 3 Product Description ........................................................................................................................ 7 Construction .................................................................................................................................... 9 Performance and Observations ..................................................................................................... 14 Cost Analysis ................................................................................................................................ 17 Summary and Recommendations ................................................................................................. 19 Implementation Strategy ............................................................................................................... 20 Appendix ....................................................................................................................................... 21 References ..................................................................................................................................... 22 IV ABSTRACT The Vermont Agency of Transportation (VTrans) installed a Bridge in a Backpack (BiaB) system, or also referred to as a Rigified FRP Tube Arch (RFTA) Structure on a low volume road in a rural setting. The value of using this system is the potential to use smaller and lighter construction equipment for a restricted delivery location such as forest or farm roads. The BiaB does not require large cranes and there is a potential for in-field fabrication of the tube arch members where large truck delivery is limited. Advantages of the system include good waterway characteristics and suitability for ledge controlled or spread footings. Disadvantages of the system are that few have been constructed and that it has aesthetic limitations. The construction of the Fairfield BiaB project proceeded smoothly. Generally, site conditions and limited experience with the BiaB led to less than ideal means and methods for construction of the system. During construction, it was noted that several opportunities remain for further expedited construction and cost reduction. Generally, VTrans’ experience with the BiaB showed that the system provides a benefit to the State. The Research and Development Section recommends the Agency continue to consider the use of the system. - 1 - INTRODUCTION The Vermont Agency of Transportation (VTrans) proposed to construct the Bridge in a Backpack (BiaB) in the town of Fairfield, on Wanzer Road. The BiaB system is a unique structure type that currently lacks a similar competitive alternative. The predominate component of the BiaB are ribbings constructed of fiber reinforced polymer (FRP) tubes made rigid by reinforced concrete. These ribbings are spaced at a regular interval and are configured to arch over the opening. The arched tubes are lightweight and can be carried into place by manual labor, thereby giving its name (see Figure 1). In order to use the BiaB system, VTrans was required to obtain FHWA approval for sole sourcing the Bridge technology. This was initially pursued through the Public Information Finding (PIF) process, which allows state transportation agencies (STA’s) to use unique products in the transportation system. The impetus of obtaining this PIF approval from the FHWA was to explore the use of a construction technique that was less equipment-intensive. Figure 1 FRP tubes can be carried into place by hand labor. (AIT) The sole source request covered the major structural elements namely, the FRP tubes and panels that are only provided by Advanced Infrastructure Technologies (AIT). Remaining components of the BiaB system could be obtained through competitive bidding and pricing. If - 2 - proven successful, the Agency could use the BiaB bridge system to save public dollars both in the short and long terms. The system’s quick and simple construction process will result in lowering initial costs. The system’s durability and inherent resistance to environmental impacts will reduce maintenance costs and extend the overall structural life span. This bridge technology was selected as an AASHTO Technology Implementation Group (TIG) Lead States Team effort. In order to promote and further refine this innovative bridge technology the AASHTO TIG Lead States Team encourages the design and construction of pilot projects throughout the country. The Public Interest Finding process is a clearly defined mechanism in Title 23 CFR 635.411, as supported by 23 USC 112(a) to allow for propriety products or materials to be used on highway products. Though 23 USC 112(a) requires competitive bidding, the FHWA has provided for an allowance to use propriety products and materials when “the need for a particular product outweighs the need to procure products competitively.” (1) The Agency chose to incorporate an Experimental Feature (EA) Research study in association with the PIF as a condition of FHWA approval. A five-year monitoring plan is currently underway to evaluate the overall value and initial performance of this technology. PROJECT LOCATION AND SUMMARY The Bridge in a Backpack was installed in Fairfield, Vermont on Wanzer Road (TH-30) at bridge 48 over the Wanzer Brook (See Figure 2). Wanzer Road receives about 200 vehicles daily. The original bridge was constructed in 1919. Figure 3 show that the bridge was very narrow (17.2 ft) and was located at the bottom of a significant sag in the roadway with steep slopes descending to and ascending away from the bridge. The roadway had a significant “S- curved” horizontal alignment through the project site. Figure 4 shows that the bridge had a timber deck on steel girders and spanned a small brook. The project scoping field report suggested that the timber deck comprised of vertically laminated 2x6 boards fastened by nails. The deck appeared to be in good condition. The steel beams were rusted and had supplemental supporting beams, which were added at a later time (see Figure 5). The substructure which carried a fair rating exhibited substantial deterioration. According to the field inspector in 2011, the rating for the substructure required a reduction in rating based on findings at the time. (2) The field investigation found that using a temporary bridge located on either side of the existing structure was not feasible due to the challenges the vertical and horizontal alignments provided. Adequate detours were available within the proximity of the project to provide essential mobility (see appendix). The project scoping report suggested that the location justified an accelerated bridge construction method with a 4-week bridge closure. The challenge with closing the roadway at the bridge site was coordinating with the nearby farms and their access to their fields. - 3 - Project Location Figure 2 Project Location (Microsoft Bing Maps) Figure 3 Bridge 48 alignment (VTrans) - 4 - Figure 4 Bridge 48 profile (VTrans) Figure 5 The underside of bridge 48 showing the added beams (VTrans) The existing substructure consisted of abutments comprising of a concrete cap setting on laid up stonewalls fortified at the base by concrete kneewalls. The abutments were placed on a timber mat (see Figure 6.) The clear span was 25.5 ft., just below the bridge seats and above the kneewalls. The kneewall clear span was 16 ft. Hydraulic engineering recommendations - 5 -