THE CONCRETE BRIDGE MAGAZINE WINTER 2020 www.aspirebridge.org

Terwillegar Park Footbridge Edmonton, Alberta CHRISTINA RIVER BRIDGE Wilmington, Delaware

MOORES MILL BRIDGE Auburn, Alabama

MAIN STREET AND GRAND BOULEVARD BRIDGES

Kansas City, Missouri

Permit No. 567 No. Permit

Lebanon Junction, KY Junction, Lebanon

Postage Paid Postage Presorted Standard Presorted FOCUS Full-Service Engineering Stantec’s bridge division serves clients’ bridge needs from conceptual design through inspection, maintenance, and rehabilitation, using whatever techniques are required.

by Craig A. Shutt

Stantec is recognized around the world for providing a wide range of architectural and engineering solutions. Its North American bridge division enhances that reputation by providing a full complement of bridge engineering services, from concept to rehabilitation.

“In the bridge sector, we pride ourselves on being a full-service company in all aspects of bridges,” says Tony Hunley, vice president in Stantec’s bridge sector. “We’re not just known as new-bridge designers. We do it all.”

Reed Ellis, vice president and bridge sector leader adds, “One thing that sets us apart is the complete range of bridge engineering services we provide our clients through all stages of a bridge’s life cycle. That includes inception, planning, conceptual design, design, and construction. It continues through regular and rope-access inspections, maintenance, repair, rehabilitation, load rating, and strengthening. We also implement bridge management systems, help bridge owners manage and prioritize repairs, and decommission structures.”

Given this range of services, Stantec establishes strong ties with departments of transportation (DOTs) and other owners that last after a specific project ends. “We form long-standing relationships, becoming a partner and consultant over the long term on that structure,” says Ellis. Expanding Inspection Services Bridge inspections have been a recent area of growth for Stantec. “In the past 10 years, we’ve seen a considerable Using rope access, Stantec performed the first routine inspection on the 1896-ft-long increase globally in owners wanting Mike O’Callaghan–Pat Tillman Memorial Bridge in 2013. The bridge is 870 ft above to inspect their bridges to improve the Colorado River. All Photos: Stantec. their asset management,” says Ellis.

6 | ASPIRE Winter 2020 The Terwillegar Park Footbridge consists of 86 precast concrete deck panels supported by bearing cables cast into the deck with 7.3-ksi high-performance cast- in-place concrete. The Terwillegar Park Footbridge over the North Saskatchewan River is Canada’s Frequently, inspections require a variety longest stress-ribbon bridge, spanning 859 ft 6 in. The structure is the first of its kind of approaches, including rope access. in Edmonton, Alberta, and the northernmost bridge of this type in the world. “In the past 10 the Society of Professional Rope Access Hunley currently is leading Stantec’s years, we’ve seen a Technicians, Ellis notes. “It was a work on a major bridge rehabilitation considerable increase complex, hands-on inspection.” and replacement initiative for the Kentucky Transportation Cabinet. To globally in owners The company is evaluating new reduce the number of substandard wanting to inspect their inspection tools, including drones. bridges, which reached more than 1000 “We’re looking internally to see how in 2018, Kentucky launched Bridging bridges to improve their we can best utilize them to provide the Kentucky, an ambitious six-year, $700 asset management.” appropriate level of inspection for each million program designed to restore bridge,” says Ellis. “They definitely show state and locally owned bridges. “Our philosophy for inspections is to promise, but we have to determine use the most effective accessibility what value is there and if we can use Stantec is serving as the prime techniques necessary to ensure we them effectively.” consultant, along with QK4 Inc. and see everything. We often combine AECOM as lead partners. The project mechanical access equipment, such as Rehabilitation Work team also includes 22 engineering, underbridge and snooper trucks, with The growth in inspections has in turn environmental, and specialty firms. rope-access techniques, especially on led to an increase in rehabilitation work. “We are performing a full-service effort: major bridges,” says Ellis. “Often, DOTs are looking to extend the program management, evaluation, service lives of their existing bridges asset management prioritization, Such inspections can create challenging rather than replacing them completely,” rehabilitation or replacement designs, situations. This was the case during the Ellis says. and construction-phase support,” inspection of the 1896-ft-long Mike Hunley says. The firms are taking a O’Callaghan–Pat Tillman Memorial Bridge decks are usually the first area programmatic approach, bundling Bridge, 870 ft above the Colorado River targeted for replacement, but joints bridges by type and location rather than and downstream from the Hoover Dam. typically receive the most attention. letting contracts bridge by bridge, and Working for the Nevada Department “Joints are the number-one challenge they are using both traditional design- of Transportation, Stantec provided the for existing bridges, because they bid-build and design-build contracts. first routine inspection of the massive can lead to deterioration of the structure while under live traffic in underlying girders and substructure A customized life-cycle cost evaluation 2013, and then inspected it every other piers and caps. The biggest part of was performed for each bridge year through 2019. our rehabilitation work is addressing considered for rehabilitation or deterioration under the joints,” replacement, which determined that In 2019, the inspection crew finished its says Ellis. To aid that work, Stantec about 40% of the structures could work on the concrete, open-spandrel incorporates new patching techniques be rehabilitated. As of August 2019, arch structure in only six days, using and protections, such as galvanic- Kentucky had awarded $113.8 million rope access. The structural engineering anode and other active cathodic in construction contracts for 190 climbing team followed practices of protection systems. bridges, and its costs were more than

ASPIRE Winter 2020 | 7 in Edmonton and the northernmost bridge of this type in the world.

“This bridge structure was only possible through advancements in concrete products,” says Ellis, who served as project leader. “The City challenged engineering firms to propose a solution that would be innovative, have a low impact on the river valley both environmentally and visually, and then achieve these goals within a tight budget and timelines.”

The stress-ribbon bridge achieved the goals by using precast, prestressed concrete. “It allowed for efficient and cost-effective construction, producing a slender and elegant bridge form.” The precast concrete deck panel design combined with the use of high-performance cast-in-place concrete allowed the Terwillegar Park Footbridge to maintain a thin deck The superstructure consists of 86 precast profile that minimized the environmental and visual impact of the bridge on the North concrete deck panels and is supported Saskatchewan River valley. by bearing cables cast into the deck 20% below anticipated budgets. By major new bridge projects, including with 7.3-ksi high-performance cast- mid-2020, contracts for more than 450 projects using alternative project delivery in-place concrete. This design allowed bridges will be let. methods, such as design-build and the panels to be cast only 16.3 in. public-private partnerships. thick. “This option was the most Kentucky’s rehabilitation projects are economical and best met the City’s designed for a minimum design “DOTs have tight budgets, and while vision and sustainability goals. And it service life of 30 years. Concrete they are stretching their resources, was delivered on schedule and within repair methods for these projects will they also have to address their biggest budget.” involve determining the best patching problems, and that often means approach, resolving the source of the their largest or most complex bridges Design-build delivery methods often deterioration, and proactively protecting or major corridor improvements that provide the best approach for large new and existing concrete surfaces from include a large number of bridges,” says projects, Hunley notes, as they allow water and chloride infiltration by sealing Hunley. “What we don’t see as much the design team to leverage their repaired substructure concrete with a right now is the average, routine bridge expertise and collaborate with the high-quality epoxy-coating system. replacement. There are far fewer of contractor to create efficiencies. That those being done individually.” approach worked well for the U.S. Since the launch of Bridging Kentucky, Route 460 Connector project on the more than 150 additional bridges have “What we don’t Virginia-Kentucky border through the been determined to be substandard Appalachian Mountains. The project due to condition or necessary weight see as much right now included the Grassy Creek Twin Bridges, restrictions. “Kentucky was slowly losing is the average, routine two six-span, 1733-ft-long structures ground to deterioration faster than it that feature a four-span cast-in-place could replace bridges,” Hunley says. “By bridge replacement. segmental concrete box-girder unit addressing 1000 of the worst bridges There are far fewer with 489-ft-long main spans and two in the inventory in a short period of approach spans with precast concrete time, the Bridging Kentucky program of those being done I-beams. The depths of the segmental will allow the state to turn the tide individually.” box girders varied from 12 ft 6 in. at and be in a position to maintain and midspan to 30 ft 3 in. at the piers. improve the overall condition of their One notable construction project is bridges into the future.” (See the Fall the Terwillegar Park Footbridge over For this project, Stantec managed field 2019 issue of ASPIRE® for a State article the North Saskatchewan River in surveying; geotechnical, roadway, and on Kentucky with more details of the Edmonton, Alberta. Stantec designed structure design; permitting; right-of- Bridging Kentucky program.) this bridge—Canada’s longest stress- way planning and mineral acquisition; ribbon bridge and the second longest and relocation of utilities and a small Signature New in the world—to link Terwillegar Park cemetery. At more than 250 ft high, Construction Projects with an existing trail system on the the two cast-in-place, post-tensioned At the other end of the spectrum, other side of the river. Spanning 859 ft segmental bridges are the highest in Stantec has recently been involved in 6 in., the structure is the first of its kind Virginia.

8 | ASPIRE Winter 2020 Leveraging the Benefits Stantec’s Service of Concrete These projects show some of the ways Stantec was founded in 1954 as D.R. Stantec has been leveraging concrete’s Stanley Associates in Edmonton, Alberta, capabilities to meet bridge challenges. by Donald Stanley, the first Canadian “Concrete designs are preferred by to earn a PhD in environmental many owners,” notes Hunley. “There engineering. After expanding through a are always regional preferences, but it variety of acquisitions, the company was is the workhorse for small- to medium- reorganized in the early 1990s as the span bridges. We can tailor it to their Stanley Technology Group. The company needs, and they see durability and went public in 1994 as Stantec. reduced life-cycle costs.” Stantec has continued to expand through Service life is a dominant focus today acquisitions, adding more than 130 firms among owners. “For major bridges, since it went public. It has approximately they’re often looking to achieve 100 22,000 employees operating out of more years of service in the initial design than 400 offices in North America and and construction,” says Hunley. For globally. that reason, Stantec designs projects with long-term maintenance in mind. “We emphasize clean, simple details, two ABC projects in Connecticut eliminating joints, and using replaceable using precast concrete elements for bearings.” abutments and wingwalls.

“We emphasize The company also has been involved clean, simple details, with sliding structures into place using various types of equipment. “Owners eliminating joints, are becoming more aggressive in and using replaceable returning roads to users quickly, so they’re looking at more options. As bearings.” some become comfortable using ABC, Stantec was the overall project design other owners are warming to it when manager in a design-build contract Concrete suppliers are aiding that work. they look for those benefits too.” for the Grassy Creek Twin Bridges, a “There is more attention paid to mix part of the U.S. Route 460 Connector designs, admixtures, exposure zones, One such project was the Interstate 84 project in Virginia. Each of the two and salt resistance,” explains Hunley. Bridges over Marion Avenue in 1733-ft-long bridges features a four-span “We’re providing more reinforcement Southington, Conn., where all three post-tensioned segmental concrete box- bar cover and increased corrosion- lanes of traffic in each direction had girder unit and two approach spans with resistant reinforcement to aid those to remain open during construction. precast concrete I-beams. changes, and suppliers are responding The twin bridges featured Prestressed with concrete mixtures with higher “The key challenge was the extremely Concrete Committee for Economic strength and improved beam shapes, steep mountain slopes at each end,” Fabrication (PCEF) 47-in.-deep beams. which are helping us meet the needs.” explains Hunley. “We used long spans Two sets of self-propelled modular to minimize the impact of cutting into ABC Solutions transporters—one for each bridge—were the slope to create foundations and used on the project. (See the Summer New techniques are needed to meet potentially undermine the next pier. 2015 issue of ASPIRE for a Project article current and future challenges. “The Terrain issues were a huge concern on these bridges.) biggest challenge we face today and drove the design and construction is designing in difficult conditions methods.” Staying open to new ideas and under ongoing traffic,” says Hunley. adopting new techniques will “Accelerated bridge construction (ABC) The segments were constructed from keep Stantec moving forward. “We methods are becoming vital to minimize the top down, using a form traveler anticipate an increase in more efficient construction delays.” along with tower cranes. “We needed concrete beam shapes to extend spans as much access as we could achieve even further,” says Hunley. “We’re in an isolated area,” Hunley says. Stantec has used a variety of ABC seeing more shapes being tried by “It was unusual to see tower cranes approaches, including prefabricating several owners. And more DOTs are usually used for tight, urban high-rises as many components as possible gaining comfort levels with accelerated working in this very rural location.” to assemble quickly at the site. “This bridge construction, post-tensioned (See the Fall 2014 issue of ASPIRE for approach is used most often where concrete bridge designs, and enhanced a Project article on the U.S. Route 460 there are lower volumes of traffic,” says rehabilitation strategies for extending Connector.) Hunley. Stantec recently completed service life of bridges.”

ASPIRE Winter 2020 | 9