Performance of Bridges That Received Funding Under the Innovative Bridge Research and Construction Program (2019) / Chapter Skim
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51 5 Conclusions and Recommendations The conclusions and recommendations in this chapter respond to the four tasks in the committee's Statement of Task: 1. Analysis of the performance of bridges that received Innovative Bridge Research and Construction (IBRC)
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52 PERFORMANCE OF BRIDGES PERFORMANCE OF THE IBRC PROJECTS IN MEETING THE GOALS OF THE PROGRAM The legislatively defined goals of the IBRC program were: 1. Development of new, cost-effective, innovative materials for highway bridge applications.
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CONCLUSIONS AND RECOMMENDATIONS 53 the early 1990s (Halladay 1998)
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54 PERFORMANCE OF BRIDGES Today most state highway agencies use externally bonded FRP reinforcement and nearly half of those that responded to the 2018 AASHTO survey use FRP rebar. However, few of the states that responded to the survey use or have specifications for FRP deck elements, FRP superstructure elements, or FRP prestressing tendons (strand or bar)
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CONCLUSIONS AND RECOMMENDATIONS 55 The creation of the IBRC program in 1998 was a timely complement to the FHWA–ONR–AISI initiative. The first five grants for HPS projects were awarded in 1999.
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56 PERFORMANCE OF BRIDGES program contributed to the reduction of costs through promotion of use of the following materials: • HPC: Use of HPC in bridge construction can reduce life-cycle cost because the durability of the material extends bridge service life and because of savings attainable in construction cost. Properties of HPC allow bridges to be constructed more quickly and with less material, compared with conventional concrete.
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CONCLUSIONS AND RECOMMENDATIONS 57 Corrosion control reduces maintenance and rehabilitation needs and extends the service life of the bridge. A properly designed monitoring program can reduce costs by alerting the highway agency to incipient problems, allowing more efficient planning of maintenance and rehabilitation.
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58 PERFORMANCE OF BRIDGES rebar, metallizing, cathodic protection, HPS, and ABC (see Table 3-3)
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CONCLUSIONS AND RECOMMENDATIONS 59 overpasses over railroads. The technologies applied were FRP decks, FRP rebar, externally bonded FRP reinforcement, SCC girders, HPC in a deck and girders, and hybrid steel girders.
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60 PERFORMANCE OF BRIDGES experience with several technologies that had reached an advanced stage of development but had not yet been adopted for highway bridge construction in the United States. However, the program's contributions could have been greater if it had stronger provisions for in-service evaluation of the technologies demonstrated and for dissemination of project results.
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CONCLUSIONS AND RECOMMENDATIONS 61 – increased durability that extends service life and reduces maintenance and rehabilitation needs (HPC) ; and – reduced user costs through faster construction or reduced maintenance frequency (ABC)
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62 PERFORMANCE OF BRIDGES these rebar materials. Promotion activities would increase awareness and could lead to increased use and increased availability.
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CONCLUSIONS AND RECOMMENDATIONS 63 develop a specification for thermal spray coating for steel beams that was adopted in 2017 (AASHTO/NSBA 2017)
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64 PERFORMANCE OF BRIDGES development (for example, nondestructive evaluation and FRP deck and superstructure elements)
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CONCLUSIONS AND RECOMMENDATIONS 65 for guiding decisions only if reliable data on long-term performance are available. Second, highway agency trials of state-of-the-art management systems and evaluation methods, or upgrades of existing systems, could be designated eligible projects to receive grants.
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66 PERFORMANCE OF BRIDGES Concrete HPC was one of the most frequently used innovative materials in IBRC projects; 34 states received IBRC grants for projects featuring HPC, UHPC, or SCC. HPC is today in general use for highway bridges throughout the United States.
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CONCLUSIONS AND RECOMMENDATIONS 67 tubes are inherently stronger and stiffer than their conventional reinforced concrete counterparts; these are valuable qualities for bridges in seismically active regions on sites with soft liquefiable soils (WSDT 2018, 7-101)
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68 PERFORMANCE OF BRIDGES Needs for advancing FRP applications include the following: • Data on durability and service life. • Filling gaps in existing standards, specifications, and guidelines for design, use, and inspection.
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CONCLUSIONS AND RECOMMENDATIONS 69 that is not widely used but that may merit evaluation and trials to assess its potential. ABC As FHWA encouraged applications for ABC projects late in the IBRC program, only about a dozen states received funding for projects that highlighted ABC as a primary innovation.
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70 PERFORMANCE OF BRIDGES • Integration of data from weight-in-motion installations with the National Bridge Inventory (NBI) data system to measure the relationship of traffic to deterioration and to support improved estimates of service life and replacement needs.
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CONCLUSIONS AND RECOMMENDATIONS 71 IBRC, but with features to improve on the results of the earlier program. The new program should incorporate the provisions described in the following paragraphs.
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72 PERFORMANCE OF BRIDGES description of monitoring and evaluation provisions. The record system should track projects through completion and through follow-up evaluation activities.
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CONCLUSIONS AND RECOMMENDATIONS 73 Emphasis Areas Emphasis areas for project selection should be determined by the federal– state consultative process previously recommended. The committee recommends that consideration be given to the following areas: • Projects that contribute to development and evaluation of designs, standards, and specifications that take full advantage of the performance qualities of advanced materials.
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74 PERFORMANCE OF BRIDGES • Development and validation of models for projecting service life and deterioration rates for use in bridge management and life-cycle cost analysis. • Long-term monitoring of the durability, performance, and costs of materials and technologies: Highway agencies will hesitate to adopt unfamiliar but potentially cost-saving technologies without strong evidence of performance over time.
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CONCLUSIONS AND RECOMMENDATIONS 75 knowledge gaps and identifies research needed to fill certain gaps (Culmo et al.
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76 PERFORMANCE OF BRIDGES should take place in several states and involve several bridge engineering firms. • Develop inspection, repair, and rating procedures for bridge components and systems that use FRP materials consistent with standard practice for concrete, steel, and timber bridges.
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CONCLUSIONS AND RECOMMENDATIONS 77 for technical exchange, and support participation of their engineers in these activities. Existing Federal Highway Innovation Programs Congress should continue to provide funding and direction in future federal aid program authorizations for the existing innovation programs administered by the FHWA Center for Accelerating Innovation.
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