SECTION 4
Process Evaluation
This section details the evaluation of the process by which TFHRC decided to fund UHPC-C research, as well as the execution of UHPC-C research and technology transfer efforts.
4.1 TFHRC UHPC-C Research Timeline
Figure 4-1 shows the timeline of UHPC deployment in the United States, including the timing of TFHRC research initiatives. TFHRC did not invent UHPC, but TFHRC labs are among the few in the United States with the tools to conduct large-scale concrete structural testing and to characterize materials. UHPC became commercially available in the United States in 2000. In 2001, TFHRC began investigating its use for U.S. highway infrastructure. By 2002, UHPC had been deployed in two bridges in Europe and one in Canada, and TFHRC began working with state transportation departments to accelerate its deployment.
In 2006, TFHRC provided technical assistance to the Iowa DOT and Wapello County in constructing the first bridge using UHPC, pictured in Figure 4-2 (Russell and Graybeal 2013). TFHRC assisted with background information, concept development, and design questions. In 2008, after extensive research and testing by TFHRC, Iowa built its second UHPC bridge. In 2009, New York State began building bridges using field-cast UHPC-C between precast elements. This practice has continued, and more than 70 bridges in New York State are known to have used UHPC-C. Since 2009, other states have begun using UHPC for bridge construction and repair.
TFHRC has conducted numerous activities supporting UHPC adoption, including research on structural properties, development of testing methods, development of design guidelines, and performance evaluations. Because of the relative benefits and costs of UHPC compared with conventional concrete described in Section 2, TFHRC has focused on encouraging the adoption of UHPC-C through research and publication efforts, including disseminating information through workshops and “consulting” informally with state and local transportation departments. TFHRC has also worked to identify knowledge gaps owner agencies and industry may have and address them through their research.
Table 4-1 summarizes TFHRC publication output for UHPC research by focus area (FHWA 2018b). Initial TFHRC research and publications focused on assembling an overview of the material, characterizing the material properties, and identifying mix design. The research has since progressed to identifying specific uses of UHPC, including UHPC-C, and developing design guides and more detailed information on material properties. A guidance document on the design and construction of UHPC-C was published by FHWA in 2014 (Graybeal 2014) and updated in 2019 (Graybeal 2019).
SOURCE: Russell and Graybeal, 2013; FHWA, 2019a, 2019b; correspondence with TFHRC staff.
Figure 4-1. Timeline of UHPC use in the United States, 2001–2019.
In 2017, UHPC-C for PBEs was selected as one of 11 innovations for the fourth round of the Every Day Counts (EDC) program. EDC is an FHWA program that works in partnership with AASHTO and other transportation stakeholders to accelerate the deployment of proven innovations at state and local levels. Transportation leaders across the country meet at regional summits to discuss the innovations and strategies for implementation. After the regional summits, State Transportation Innovation Councils meet to evaluate the innovations and direct their deployment. TFHRC staff led the UHPC-C EDC activities.
Progress for the EDC program is characterized in five innovation implementation stages: before implementation, development, demonstration, assessment, and institutionalization (that is, the innovation is fully integrated into practice). The EDC program assessed that the baseline
SOURCE: FHWA, 2019c.
Figure 4-2. Mars Hill Bridge, first U.S. bridge constructed with UHPC components.
Table 4-1. Review of TFHRC UHPC publications.
| Subject | Description | Journal/ Magazine Articles | Reports | Tech Briefs | Presentations | Publication Date Range |
|---|---|---|---|---|---|---|
| Cross-Cutting UHPC Research | ||||||
| UHPC Material Characterization | Details of the material properties and engineering characteristics | 8 | 5 | 3 | 5 | 2006–2018 |
| UHPC Program Overview | Description of the program and its purpose | 4 | 1 | 1 | 2 | 2009–2018 |
| UHPC Computational Modeling | Mathematical modeling to determine properties of UHPC materials | 0 | 2 | 2 | 0 | 2010–2014 |
| UHPC-C Research | ||||||
| Field-Cast UHPC-C for Modular Components | Field-cast components connecting PBEs such as decks and girders | 7 | 7 | 8 | 8 | 2010–2019 |
| Other UHPC Applications Research | ||||||
| UHPC Girder Research | Design guidelines and material characterization of deck support elements | 2 | 4 | 3 | 2 | 2006–2017 |
| UHPC Precast Deck Panel Research | Design guidelines for a precast UHPC bridge deck element | 0 | 1 | 1 | 0 | 2007 |
| UHPC for Bridge Preservation | UHPC for bridge repairs and maintenance to extend life span, such as bridge deck overlays | 1 | 1 | 1 | 0 | 2017–2018 |
NOTE: PBE = prefabricated bridge element; TFHRC = FHWA Turner-Fairbank Highway Research Center; UHPC = ultra-high performance concrete; UHPC-C = UHPC connections.
SOURCE: Subject areas are adapted from FHWA, 2018b.
number of states attaining demonstration, assessment, or institutionalized implementation of UHPC-C for PBEs was 21 in January 2017 and 40 by the end of the program in December 2018 (FHWA 2019a).
4.2 Alignment of TFHRC UHPC-C Research and FHWA Strategy
Table 4-2 shows the initial assessment, based on interviews and data collection, of how TFHRC research on UHPC-C aligns with the strategic objectives from the FHWA Strategic Plan, Fiscal Year 2019–2022 (FHWA 2018a). The assessment found that the TFHRC UHPC-C research program was advancing multiple FHWA strategic objectives and, therefore, was strongly aligned with FHWA strategy.
4.3 Effectiveness of TFHRC Efforts
Results from the stakeholder interviews indicated strong agreement that TFHRC’s UHPC-C technology transfer efforts are highly effective. Interviewees consistently described how helpful TFHRC had been in promoting and supporting UHPC-C adoption. Several interviewees felt the current U.S. adoption of UHPC-C could be attributed almost entirely to TFHRC’s efforts. Stakeholders did note that proprietary UHPC suppliers carry out their own stakeholder outreach
Table 4-2. Alignment of FHWA strategic objectives with TFHRC UHPC research.
| FHWA Strategic Objective (FHWA 2018a) | TFHRC UHPC Research Alignment |
|---|---|
| Strategic Objective 1: Save lives by expanding the use of data-driven, systemic safety management approaches and by increasing the adoption of proven safety solutions by all road owners. | Preliminary results indicate that the use of UHPC-C with PBEs and ABC methods will decrease construction time and lane closures, improving safety for motorists and construction workers. |
| Strategic Objective 2: Improve program and project decision making by using a data-driven approach,assetmanagement principles, and a performance-based program thatwill lead to better conditions and more efficient operations. | TFHRC has collaborated with industry stakeholders to identify applications that can most benefit from UHPC for a variety of social and economic reasons. |
| Strategic Objective 3: Increase freight and people mobility and reliability by building effective partnerships and encouraging targeted investments. | TFHRC has collaborated with owner agencies and educational institutions and has invested in additional research and technology implementation. |
| Strategic Objective 4: Enhance the safety and performance of the nation’s transportationsystem through researchand by accelerating development and deployment of promising, innovative technologies and practices. | TFHRC has accelerated UHPC-C deployment in the United States by publishing research, producing technical guides, and conducting direct outreach, including workshops and EDC-4. As of 2018, 33 states had attained demonstration, assessment, or institutionalized stages of implementation (FHWA 2019a). |
| Strategic Objective 5: Modernize or eliminate obsolete, unnecessary, or duplicative policies and regulations to accelerate all phases of project delivery, stimulate innovation, and reduce administrative burdens. | TFHRC research has resulted in technical publications describing UHPC materials properties anddesign guides owner agencies can use to draft design and construction standards. |
| Strategic Objective 6: Transform the workforce and resource management approach to ensure FHWA is properly structured, skilled, and equippedto deliveroutstanding customer service to our partners andthe traveling public. | Initial interviews indicated that stakeholders highly value the quality and skill of the TFHRC staff conducting UHPC-C research and outreach. |
NOTE: ABC = accelerated bridge construction; EDC = Every Day Counts program; PBE = prefabricated bridge element; TFHRC = FHWA Turner-Fairbank Highway Research Center; UHPC = ultra-high performance concrete; UHPC-C = UHPC connections.
SOURCE: FHWA, 2018a, 2019a, 2019b.
efforts but indicated that FHWA, as a highly respected and unbiased source of information, likely had the most influence on UHPC-C adoption in the United States. Many researchers and owner agencies recognized TFHRC as both their preliminary and their primary source of information about UHPC-C, initiating their engagement with the material and continually serving as a guide for best practices through workshops, EDC initiatives, research publications, and technical reports.
Interviewees indicated that Ben Graybeal, leader of the bridge engineering team that oversees TFHRC’s UHPC-C research and outreach initiatives, has served as a champion for UHPC-C in the United States, with a particularly sizable influence on adoption. TFHRC, through Graybeal and his team, consults informally with stakeholders free of charge, which interview respondents described as “invaluable” to their research and adoption efforts. Many stakeholders specifically described the value of engaging directly with Graybeal, noting how knowledgeable and accessible he is in responding to stakeholder questions and providing real-time assistance during UHPC-C applications. While a strong champion can often be key to adoption of an innovation, relying heavily on a single person can also be a risk.
