Wave of the Future Trendy Novelty? Accelerated Bridge Construction in Alabama: Wave of the Future or Trendy Novelty? With today’s presentation I plan to explain ABC, show some examples others have done, and touch on the future of ABC in Alabama.

Accelerated Bridge Construction - innovative planning, design, materials, construction methods safe and cost-effective reduce the onsite construction time Accelerated bridge construction is using innovation in planning, design, materials, and construction methods that are project enhancing, that is, provides a safer construction zone with financial benefits as well as shortening the time roadway users are affected by construction activities.

Why Accelerated Bridge Construction? Rehabilitate / Replace Existing Structures Common Practices: Detour Temporary Bridge Stage Construction All this begs the question, “Why ABC?” Well, the nation’s highway bridge system was for the most part completed some time ago. Since that time traffic volumes have increased, load calculations have been modified, and structures built some time ago have reached the end of their structural and/or functional life. As a result, many structures are undergoing rehabilitation and/or replacement. Currently we use different strategies to deal with these structures, among which are off-site detours, on-site detours or temporary bridges, and stage construction. Each of these is intended to allow traffic to continue to flow, albeit with some restriction, while a rehab or replacement is underway.

BUT . . . ABC is NOT the answer for all projects! However, ABC is not universally applicable. There is a process for determining which structures or locations would be best suited to ABC, which I will touch on later.

ABC under EDC2 : Geosynthetic Reinforced Soil – Integrated Bridge System (GRS-IBS), Prefabricated Bridge Elements and Systems (PBES), Slide-In Bridge Construction There are 3 ABC innovations the Feds are currently encouraging. Those being GRS-IBS, Prefab bridge elements, and slide or roll in bridge construction. There is a GRS-IBS project being hosted by Marshall County. Alabama already has experience with pre-fab elements as most of our county bridges are almost completely pre-fab. Also, let’s not forget the I-10 bridge over Mobile Bay, a photo of which is the predominant background of this presentation. It was built with pre-fab superstructures. Bridge sliding or rolling, however, appears to be a new technology that has the potential to improve the safety at the construction site, improve our image among the traveling public, and save us money in the long haul. ALDOT currently has projects in pre-fab elements and bridge sliding.

Prefabricated Bridge Elements and Systems Built offsite Controlled environment Proper curing Time in work zone Site / Environmental impact I’ll start by introducing Prefabricated bridge elements and systems. These are bridge components or entire bridges built offsite and transported for quick installation. They offer a number of advantages over cast–in–place bridge construction. For instance, they can be built offsite while earthwork and foundation construction is underway, shortening onsite construction time that impacts traffic from months to days or hours. They’re manufactured in a controlled environment where the use of consistent materials and methods contributes to uniform quality in the end product. Flexible start times for manufacturing components ensures adequate time for proper concrete curing for good long–term performance. Less time in the work zone reduces safety risks,. PBES construction also offers to minimize site impact, a necessity when working over wetlands or other environmentally sensitive locations.

Prefabricated Bridge Elements Prefabricated bridge elements include . . .

Partial and Full ̶ Depth Deck Panels

Pier Caps . . . pier caps . . .

Columns . . . columns . . .

. . . and footings. Footings

Prefabricated Bridge Systems Complete superstructure Complete substructure Entire bridge Prefabricated bridge systems include complete superstructures, complete substructures, and entire bridges.

This is a bridge superstructure being moved in Utah This is a bridge superstructure being moved in Utah. They’re using SPMTs, or Self-Propelled Modular Transports. A Self-Propelled Modular Transporter is a combination of multi-axle platforms operated through a state-of-the-art computer-controlled system that is capable of pivoting 360 degrees as needed to lift, carry, and set very large and heavy loads of many types including bridges,

Space shuttles . . .

And the occasional freighter laying around that needs dusting underneath.

Minnesota DOT – Maryland Avenue Bridge Move using Self-Propelled Modular Transports Here are two videos showing how Self-Propelled Modular Transports are being used to install complete bridge superstructures. Both videos are about the same bridge move. The first is a time-lapse video, so you’ll have to watch closely.

Slide In Bridge Construction New bridge on falsework (existing traffic uninterrupted) When all elements completed Road closed (a week or less) Existing bridge removed New bridge moves into place On a slide project, a new bridge is built on temporary supports, usually parallel to an existing bridge. During construction, traffic continues uninterrupted on the existing structure. When construction is completed, the road is closed temporarily. The existing structure is demolished and removed and the new bridge is positioned ("slid or rolled") into place and tied into the approaches, generally within 72 hours.

Michigan Route 50 Bridge Slide This is a video of a bridge slide that happened in Michigan last October.

NV Mesquite Jack Operation This is a video showing one method to move a bridge. The video begins at the end of a push cycle. Once checks are made to ensure equal progress, the push jack is re-set by pulling itself forward to the next set of slots. Once set, the operator again checks to ensure all systems are synchronized and then reverses the jack operation to push the bridge again continues its trek toward its final destination.

Madison Milton Bridge Slide On April 10, 2014, the slide of the Milton-Madison Bridge was completed. At nearly a half-mile long, this is the longest bridge slide of its type in North America, perhaps the world. The slide occurred over a two day period with the actual slide time being approximately 12 1/2 hours. The total slide distance was 55 feet,

Wave of the Future Trendy Novelty? or Recall at the outset I posed the question as to whether ABC is the future for ALDOT or just a novelty. Well, in order for it to become a regular activity there must be . . .

Necessary For ABC: ü Technology Transfer Bridge selection tool Institutional Commitment ? - TBD . . . the transfer of ABC technology, ● which is happening, ● a tool for deciding which projects would benefit from ABC . . . ● which needs to be developed. Let me pause here to say that currently the selection method consists of a bridge engineer looking at a set of bridge plans and doing a cost analysis on what’s currently proposed as well as an ABC alternative. If it appears the ABC alternative is feasible and cost effective, a proposal is then made to the Region Engineer and his staff to decide whether to move forward with that proposal or not. This is not a practical or sustainable practice simply because in order for ABC to become SOP, there needs to be . . . ● a commitment to that practice by the institution. This is because real innovation involves people in nearly every aspect of project and plan development, from the Director to the administrator in Transportation Planning to the engineers in Design and M&T to the plan detailer in Bridge. This is simply because real innovation is more than a fancy new way to build a bridge. ABC is just one spoke on the wheel of transportation innovation. When and if ALDOT adopts that mindset, then we will see these and other creative methods of project development become a regular part of our work.

For instance, this is a diagram of the ABC selection tool used by the Utah DOT, probably the most ABC developed state in the nation. It took them time and a lot of experience to develop this flowchart, but they have successfully done so. I know this chart isn’t legible and for this example it doesn’t have to be. Rather what this chart shows is that innovation is not limited to any particular bureau, but is instead a department wide effort. Hopefully someday Alabama will be featured somewhere for our advances in transportation innovation. Thank you very much.