INSIDE/OUT ISSUE 65
SPRING
NEWSLETTER
APRIL 2017
Seismic Design Considerations for Accelerated Bridge Construction Technologies Lee Marsh connects the dots between seismic design principles and bridges built with Accelerated Bridge Construction (ABC) technologies. ABC technologies offer efficient methods for construction of new bridges or replacement of bridges throughout the United States. According to the Federal Highway Administration, U.S. departments of transportation that employ ABC technologies can often Lee Marsh replace bridges in very short time frames, depending on the type of bridge. Often, key components can be placed within 48 to 72 hours shaving much time off bridge construction efforts. Such short time frames are often achieved by constructing new bridge superstructures off site then transporting and securing the finished integrated assembly to its final location. ABC technologies can also be used for the substructure and foundations creating additional time savings in on-site construction. ABC technologies have been used by BergerABAM’s engineers for years. Prestressed concrete girders, precast columns, pile caps, and other bridge elements fabricated off site are, in fact, ABC technologies, even though such technologies have only recently become known as ABC. Although ABC is fast and efficient, safety is never compromised. In fact, the state-of-the-art ABC planning, design, and construction methods can often produce
safer bridges that are more durable and provide longer service lives compared to traditional bridges. Bridge safety considerations include proper load limits, quality construction, and protection from natural hazards, such as floods, high winds—including hurricanes and tornados —and earthquakes. Before applying ABC technologies to bridge design in any seismic region of the country— whether it be a high or low seismic region—a fundamental understanding of bridge seismic performance is paramount. In January, at the Transportation Research Board’s 96th Annual Meeting in Washington, DC, the president and chief executive officer of BergerABAM, Lee Marsh, participated in a workshop addressing seismic concerns of ABC substructures, along with design recommendations and field implementations for the most commonly used ABC details. While the overall goal of the workshop was to examine many of the performance, design, and behavioral issues of proposed energy dissipating (ED) elements used in ABC in seismic regions, Lee’s part of the workshop covered the fundamental principles of seismic design as they relate to ABC technology. Seismic design has three guiding principles that have been used for years in conventional construction but are also applicable to bridges built with ABC techniques. These principles were discussed in the workshop as described on the following page. (continued on page 2)
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1. Seismic design allows damage to specific elements of bridges. 2. Bridges are made damage-tolerant by careful detailing of these elements. 3. All other elements of the bridge are capacity protected to prevent damage to them. Regarding the first principle, designing a bridge that remains undamaged during a moderate-to-strong earthquake is not economically practical. The forces that bridge columns and foundations (substructures) must deal with to remain undamaged during such an earthquake would require more material and reinforcement than is practical for ordinary bridges. This is true in all but the lowest of seismic regions. However, as the second principle states, a bridge can be designed to tolerate damage by careful detailing of the bridge’s substructures. The key is to build the bridge in a pliable but still strong (i.e., ductile) manner so that those substructure elements can withstand inelastic damage—in a similar way a coat hanger can be bent back and forth —without collapsing. These elements are known as ED elements as they absorb and dissipate an earthquake’s kinetic energy. As the third principle states, all other bridge elements that are not part of the primary ED system are “capacity protected” (CP) elements. In other words, if one element is ductile and the tensile strength of it (i.e., the ability to be stretched out without breaking) is less than the strength of the other connected elements, the entire system will exhibit ductile behavior based on the behavior of that one ductile weak-link element. This behavior provides a significant additional advantage, in that once the intended elements reach their yielding resistance-that is, when these elements deform-the forces on other elements of the system do not increase. Again, the yielding bent coat hanger analogy applies. This force-limiting characteristic of the system means that somewhat larger earthquakes than the size of earthquake for which the bridge is designed can be resisted. This is a useful feature because earthquakes are anything but predictable.
An illustration of the relativity between ABC bridge construction joints and ABC bridge damage-tolerant elements.
When ABC technology relies on precast elements, the locations of construction joints relative to those damagetolerant elements are critical. Often, both are at the same location, which means the construction joints must be able to withstand the expected earthquake damage. This is shown in the figure to the left where two ED elements are next to construction joints. However, many other joints are in CP areas of the structure and thus do not need the special detailing and ruggedness of the ED elements. This control of ED or damage-tolerant elements helps control the overall cost of the structure because CP joints are much simpler than ED joints.
With seismic principles explained, applying them to ABC technology was then explored in the workshop with several common methods of joining precast elements and with emerging technologies that are becoming available to engineers, including the use of unusual materials, such as shape-memory alloys (think eye glasses frames) and precast, prestressed concrete columns. As a result of the workshop, attendees were able to learn more about the following. • • • •
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Typical seismic design performance objectives. How these are achieved with current design methodologies. How ABC connection types affect seismic design. Consider where we are in the development of deployable technologies.
Inside/Out Newsletter
Rail Trench Project Wins International Award for Innovation The innovative method of both design and construction resulting in more capacity and fewer delays made the project a worthy winner. On 20 January 2017, IHS Maritime & Trade awarded the Port of Vancouver USA’s West Vancouver Freight Access (WVFA) Trench project its IHS Dredging and Port Construction Innovative Project Design Award. Completed in August 2015, the trench serves as the new east-west rail entrance to the Port. Via the trench, trains are brought under the Columbia River railroad bridge preventing conflicts with mainline traffic. Prior to the WVFA project, trains entering the Port blocked the mainline, causing local, regional, and systemwide delays. The purpose of the WVFA program was to create a new, grade-separated access directly into the Port and to increase the capacity of the internal rail An aerial view of the Port of Vancouver USA’s West Vancouver Freight Access Trench Design project. system. Before the new entrance could be built, however, strict requirements had to be met. A 23.5-foot clearance below the bridge was required for the new rail line, and because of this, it had to descend more than 14 feet below the 100-year flood elevation. The Port wanted trains to remain in operation during a flood event, so protecting the rail line from flood waters was a critical design goal. As a result, the quarter-mile-long rail structure was built with reinforced concrete flood walls that extend above the 100-year flood elevation. Buoyancy, seismic, and lateral earth loads are resisted by 410 steel piles supporting 14,000 tons of concrete. As a design consultant on the project, BergerABAM provided structural and seismic design, stormwater and pump station design, utility coordination, and construction support. Editors/Contributors Nora Bretaña
Boeing North Bridge Gains Award from Precast Concrete Institute
Danny Christian
On 16 January 2017, the Precast Concrete Institute (PCI) awarded the Boeing North Bridge project a Best Special Solution Award in the Best Transportation Special Solution category. The PCI design awards program is currently in its 55th year and recognizes projects using precast concrete that demonstrate excellence in design and quality of construction.
Karen Harbaugh
Located at Boeing’s Renton, Washington, plant, the three-span, 245-foot-long bridge is used to transport completed aircraft from the assembly facility to Renton Municipal Airport where the planes undergo final inspection before they are distributed to clients. With Boeing’s plans to increase production and rollout of the 737 Max, the bridge needed to be built on an expedited schedule. To meet these scheduling requirements, BergerABAM used ABC technology.
Lynn Enebrad Jana Roy Diann Scherer Renée Stiehl Dee Young Design and Production Renée Stiehl To update your contact information, please e-mail newsletter@abam.com
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Envision at BergerABAM: A Look Back at the Previous Year The firm’s commitment to sustainability continues to grow. Have you noticed over the past year the number of clients and projects requiring sustainable infrastructure solutions? This growing shift to cost-effective and resilient projects that support a community’s economic and infrastructure needs is confirmed by the increased practice and credentialing in Envision, a guidance and rating tool for sustainable infrastructure. By the end of 2016, the number of Envision-certified projects nearly tripled from 9 to 25, while the number of Envision Sustainability Professionals (ENV SP) exceeded 5,000 ENV SPs in 20 countries. The flexibility of the Envision rating tool, developed by the Institute for Sustainable Infrastructure (ISI), is demonstrated by the variety of projects using it. Thus far, most Envision-certified projects are water related: waste water treatment plants, stormwater and water distribution, and transportation projects. However, Envision can be applied to other types of infrastructure projects, such roads, bridges, and airports. The growth can also be attributed to the adoption of Envision by public agencies, as seen with the Los Angeles County Department of Public Works in October 2016 and the City of Los Angeles in November 2016. The Sun Valley Watershed project, in which the two agencies collaborated to earn a Platinum award, is an example of their commitment to sustainable development. BergerABAM verified the certification of this project, and three others for the ISI. BergerABAM has been a part of the Envision community since its inception in 2012. The company is involved with the ongoing development of the Envision guidance manual and continuing education. In the past year, BergerABAM’s commitment to sustainability continued to grow by supporting their employees with professional development opportunities, committee time, and training. Eight more employees earned their ENV SP credential, joining a group of 25 ENV SPs across all of the sectors in the company. BergerABAM trainers provided an ENV SP training workshop to colleagues outside the company when they attended the American Society of Civil Engineers (ASCE) PORTS ‘16 conference in New Orleans, Lousiana. In addition, BergerABAM ISI trainers held ENV SP trainings in Hawaii for TeacHawaii in February 2017 and at the Society of American Military Engineers Sustainability Forum in Seattle in March 2017. About ISI and Envision Envision was developed by the ISI. The ISI was founded by the American Council of Engineering Companies, American Public Works Association, and ASCE in joint collaboration with the Zofnass Program for Sustainable Infrastructure at the Harvard University Graduate School of Design. Envision is a guidance tool that can help infrastructure stakeholders make decisions towards sustainable infrastructure. More Information on ISI and Envision can be found on the ISI website at https://sustainableinfrastructure.org.
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Inside/Out Newsletter
New Technical Staff Join Our Northwest Offices We are pleased to welcome the following new team members to BergerABAM. FEDERAL WAY OFFICE Jourden Makinen, EIT, joins the Public Works and Transportation Department as an engineer-in-training. He worked as a field engineer on the State Route 520 bridge demolition and construction of the west transition span, mezzanine deck, bridge belvederes, and sentinel towers of the bridge. His experience includes constructing road decks, elevated concrete structures, and steel structures. He has specific experience with demolition and the removal of elevated concrete structures and bridges. Jourden earned his bachelor’s in civil engineering from Washington State University. RJ Nueske, EIT, is an engineer-in-training with the Buildings Department. He has earned LEED Green Associate certification and is currently pursuing Certified Document Technician credentials. RJ recently graduated from the University of Washington with a master’s in structural engineering and earned his bachelor’s in architectural engineering from the University of Wyoming. Rory Jens, EIT, joins the Waterfront Department as an engineer-in-training. He has structural and civil engineering experience
involving structural analysis, design, and evaluation, and preparation of calculations, drawings, and budgets. Rory earned his bachelor’s in both civil engineering and mathematics from Seattle University.
Clemson University and bachelor’s in community and regional planning from Appalachian State University. He is a member of the American Institute of Certified Planners and the American Planning Association.
SEATTLE OFFICE
PORTLAND OFFICE
Luqman Munir, EIT, is an engineerin-training for the Public Works and Transportation Department. Before joining BergerABAM, he was the assistant management specialist for the Massachusetts Bay Transit Authority in Charlestown, Massachusetts. Luqman earned his bachelor’s in civil and environmental engineering from Northeastern University.
William Phaup, PE, SE, MLSE, joins BergerABAM as a structural project engineer. His expertise is in the design and construction of industrial structures in high-wind and high-seismic environments.
VANCOUVER OFFICE Sam Rubin, AICP, is a certified environmental planner who has provided professional city and regional planning services and geographic information systems (GIS) analysis in the states of Washington, Minnesota, and South Carolina. Most recently, Sam worked as a community development planner/ GIS analyst in Kelso, Washington. His experience also includes corridor management studies, comprehensive plans, regional transportation plans, homelessness plans, and community coalition building. Sam earned his master’s in city and regional planning: GIS and land use from
William’s experience includes design, construction support, permitting, quality assurance, and feasibility studies. His past projects include a major remodel and addition for a materials handling and shiploading facility at the Port of Portland; a postcatastrophe reconstruction project at a San Francisco oil refinery; designing cast-in-place gravity columns, lateral force-resisting systems, and deep foundations for two mixed-use luxury towers; and laboratory biaxial simulation and examination of as-constructed dam strength under earthquake loading. William earned a bachelor’s and master’s in civil engineering from the University of Colorado-Boulder. He is a member of the American Society of Civil Engineers, American Concrete Institute, Structural Engineers Association of Oregon, and International Code Council.
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