Background 

During the conceptualization of the Concrete Bridge Engineering Institute there were several recurrent themes:  A continuity of the expertise and continued development of new subject matter experts in the field of concrete bridges, continuous improvement of the quality of construction, minimizing potential for construction issues, and realizing the benefits of bolstering expertise especially in highly technical and specialized operations.  Training was identified as a significant component of CBEI, however serving as a hub for dialogue and discussion on design and construction of concrete bridges are seen as paramount in its mission.  Recognition among many stakeholders in the industry of these and other reasons led to the genesis of CBEI. 

In 2015 the AASHTO Technical Committee T-10 Concrete Design, some of the items identified as part of its vision were ensuring concrete bridges are:

• Resilient, durable, sustainable and uniformly safe over their life cycles,
• Easily maintainable,
• Cost-effective,
• Constructed with minimal disruption to the traveling public,
• Adaptable to functionality and climate change,
• Proportioned and detailed for multi-hazards as appropriate, and
• Designed, proportioned, detailed, constructed, inspected and maintained by a knowledgeable workforce.

Some of the strategies in pursuing this vision included items that ultimately spawned the idea for a concrete bridge center. One of the strategies recognized the benefits of having a repository of information for concrete bridges.  Taking the concepts from idea to the first steps of implementation happened during conversations in Montgomery, Alabama at an AASHTO Committee on Bridges and Structures meeting a few years later asking, what could be involved in a national center serving concrete bridges.  The AASHTO Technical Committees Concrete Design, Construction, and Bridge Preservation were very important in bringing the concept to action.  Their support and collaboration remain invaluable and integral to the program. 

Soon after the above discussions, there was a portion of the IH35/US 183 segmental bridge direct connector in Austin, Texas that was being decommissioned due to a change in alignment.  Recognizing this would be a nice sample to keep, TxDOT salvaged portions of the bridge and transported them to the CBEI site (Figure 1). These served as some of the initial components in the Bridge Component Collection.  The collection is envisioned to illustrate some best practices but also where a defect or lack of maintenance has led to an issue or backfired.  Each of these items has a story and may illustrate difficult details, insufficient details, resulting poor performance, and unique or complex details.  Part of the impact with the collection is to highlight how important responsibility in ensuring these structures are safe and durable for all of the various roles on the project.        

Development of the three pillars

A lot of the initial work was in the area of post-tensioning.  An international benchmarking study on post-tensioning technology, in particular Electrically Isolated Tendons (EIT), led to further brainstorming and discussion further to the earlier visioning.  As part of an FHWA Global Benchmarking Program study, a group from the USA visited projects in Switzerland and Italy, and met with international correspondents to share best practices as well as challenges they faced.  During the exchange, Max Meyer, PhD shared some of the action their company had taken to help develop and effectively train personnel in a hands-on approach using full-scale components at the VSL PT Academy in Thailand. The benefits of the program and incorporating aspects of it seemed like a natural next step, not only for a post-tensioning laboratory in the USA, but also the other pillars of the program.  Participants in the Benchmarking Study from the USA included Kevin Western, Gregg Freeby, Miroslav Vejvoda, Zachary Haber PhD, Reggie Holt, Michael Brown PhD, and Graham Bettis (Figure 2). As part of the Benchmarking program, a presentation which included information on the PT Installer Training Center, is provided at (https://international.fhwa.dot.gov/programs/mrp/electrically_isolated_tendons_webinar.cfm). The following is the report generated from the study: Electrically Isolated Tendons in European Transportation Structures, FHWA Global Benchmarking Program Report, FHWA-PL-20-013. Partly as a result of the trip, collaboration on an international level is continuing and brings value in advancing the state of practice in post-tensioning, and also other concrete bridge related items.  

Since that study there have been several meetings and initiatives.  A PT Technology Exchange meeting was held in conjunction with the ASBI Convention in Austin, TX in 2022.  Participants included stakeholders from all over the world including bridge owners and transportation agency representatives sharing their experiences with post-tensioning and advancements in the industry.  FHWA and CBEI staff have also been actively engaged along with US industry partners in international efforts at fib, including participation in the fib task group 5.14 Durability of Post-tensioning Tendons. This task group is working on an update of the widely referenced fib bulletin 33 published in 2005 and merge with the FHWA's technical report "Methodology for risk assessment of post-tensioning tendons.”  Two pilot projects have also been already completed in the US incorporating EIT within the post-tensioning tendons.  These were presented in the Spring 2019 and Summer 2023 issues of ASPIRE.     

One of the first items identified for CBEI was related to creation of a PT Laboratory.  Initial work in this area started through a Broad Agency Announcement (BAA).  Further discussions led to the PT Laboratory conceptualization followed by envisioning the three pillars, discussed in the Fall 2022 issue of ASPIRE.  There were lots of potential topics that were discussed and likely added in the future, but three topics rose to the top of the list as the three pillars.  The focus on best practices for bridge deck ensuring their performance became an obvious target and identified as one of the three pillars.  The long-term performance of bridge decks is a function of the proper initial construction and peaks a lot of interest given large area of bridge decks in the US and their functional importance.  Bridge decks are something from a construction and maintenance perspective that all departments of transportation are engaged with on a large scale.  A focus on a training program for construction inspection of bridge decks was identified as one of the important, initial programs.  The concrete materials for bridges program serves as the third pillar. There was a recognition of the importance of proper concrete mix designs for a wider audience to have an understanding of the what’s and why’s. Structural engineers as an example tend to focus on the structure, rather than materials, but a foundational understanding of the materials can be very helpful and is further compounded by ongoing changes in the industry.  Concrete materials in the modern environment, include components of sustainability, challenges with material availability, and new advances in materials.  Given the national scope, regional differences within each of the three pillars are important to be incorporated both from a construction methods and detailing perspective as well as a defect and environment perspective.        

A lot of training in the industry has been solely web-based or classroom-based.  From the collaboration efforts mentioned earlier, the use of hands-on training outside of the production environment represents a unique and valuable experience.  The ability to illustrate concepts, defects, and best practices in a hands-on manner, especially in technically demanding operations such as with post-tensioning can accelerate and strengthen the learning process.  Whether it is walking through the concrete durability sites (see article in the Winter 2023 issue of ASPIRE) or mixing, testing, and injecting grout, a hands-on component makes a huge difference.  Or another example, for a concrete deck, working through a dry-run and seeing the issues of insufficient cover can be a good exercise.

It is also critical to bring-up and match the robustness of the training and certification programs to meet the importance of the application.  As seen in examples from other types of structures, such as welding in steel bridges, detailed and stringent training and certification programs have been developed to align the importance of the application with the requirements to achieve good workmanship.   Training and certification programs for the various roles are seen as important for not only contractors, but also engineers and inspectors.    

Progress and schedule

We are excited to see the progress.  The concrete bridge component collection already includes several impressive items and looking to continue to add to it.  We had the kick-off meeting for the Transportation Pooled Fund for the Concrete Bridge Engineering Institute earlier this year, in mid-June 2023.  Several participating state’s transportation agencies and the FHWA are shaping the future of CBEI.  CBEI has already been a platform for several discussions and actions within concrete bridges.   

Working with the industry partners such as ASBI, PCI, PTI, and NCBC has been naturally very important.  The input and collaboration of those organizations and their members is key in establishing best practices and training personnel.  We all are working toward the same goals and see value in the partnerships.  Recent approval of adoption of the PTI/ASBI M50.3-19 and PTI M55.1-19 specifications within the next editions of the AASHTO LRFD Bridge Design Specification and AASHTO LRFD Bridge Construction Specification represent a collaborative effort among FHWA, AASHTO T-10 Concrete Design Committee, AASHTO T-4 Construction Committee, ASBI, and PTI and support by CBEI. 

The significant effort is on collecting and reinforcing best practices.  However, there is also appetite for advancing new and underutilized technologies.  In general, items considered are relatively far advanced in their Technology Readiness Level.  We are hoping to see inclusion of items such as replaceable post-tensioning tendons, post-tensioning grout monitoring, and other implementable technologies.

Closing

We look forward to CBEI serving as a platform for stakeholders to help shape the best practices and developing the next generation of concrete bridge experts.  Thank you to our State Department of Transportation partners and industry partners for your support.