A new center for proton therapy, one of only 20 such centers in the nation, will open in mid-2019 on the campus of Sibley Memorial Hospital, a member of the Johns Hopkins Health System. The National Proton Therapy Center will incorporate state of the art clinical technology and the capability to conduct advanced translational research. The three-story, 72,000-square-foot building designed by Stantec features four proton therapy treatment rooms along with clinical and general exam rooms and an imaging department.
Parent company Schnabel Engineering has worked at Sibley since 1957. Schnabel Engineering DC has been involved with this project since 2015, as a prime consultant to Sibley Memorial Hospital. Due to our deep knowledge of campus subsurface conditions, Sibley engaged us to develop the soil characteristics of the new building site through a subsurface exploration consisting of six borings, laboratory testing, and a report containing design and construction recommendations for associated earthwork, foundations, retaining walls, and drainage. During construction, we provided observation and testing services related to foundations: 115 drilled shaft subgrades and their readiness for placement of concrete.
Delon Hampton & Associates hired us to evaluate the geotechnical characteristics of subgrade materials in an existing asphalt parking lot fronting the site in preparation for repaving with porous material. The task involved infiltration testing, test borings, soil laboratory testing, and a report documenting the data, analysis, conclusions, and design recommendations.
Decades after its 1976 opening, the Smithsonian’s National Air and Space Museum has embarked on a long-planned full building renovation. The goal is to transform one of the world’s most visited museums into a more innovative and engaging visitor experience while also advancing intense security measures. Outcomes will include a new exterior and mechanical systems, increased storage capacity, and updated security.
As geotechnical engineer on the Quinn Evans Architects team, we began working on the project in 2014. Our scope of work required a site subsurface investigation, development of geotechnical characteristics, and provision of preliminary recommendations for foundations and related earthwork during schematic design. Our involvement has been steady through the construction documentation phase.
Due to the renovations, loads on existing foundations increased by as much as 50 percent. Our preliminary analysis concluded that they will be capable of supporting the new loads. We also provided recommendations for new foundations to support the wing-like vestibule structures that will grace the north and south entrances.
The multi-phase, multi-year renovation of the 675,000-square-foot facility—prominently located on the National Mall—is expected to conclude in 2021, with many exciting milestones along the way. Read more about it here.
The Glover Park neighborhood, known for its strong retail mix and charming residences, continues to expand through thoughtful renovation and new development. Developer JBG Smith is contributing to the neighborhood’s allure with The Glover House, located at 2101 Wisconsin Avenue NW. Featuring picturesque rooftop views of nearby Georgetown, the new development will consist of 226 apartments, including two-level townhouse-style units, and 20,000 square feet of food-focused retail, with Trader Joe’s as the anchor tenant.
The site was formally home to the Georgetown Holiday Inn built in the 1970s. The seven-story tower portion of the original hotel structure is being renovated, a new four-story wood-framed apartment wing, and below-grade parking are under construction. Completion is anticipated for spring 2019.
As the geotechnical engineer, we conducted an extensive subsurface investigation and provided recommendations for foundations, earthwork, sheeting and shoring, subdrainage and lateral earth pressures. We recommended a combination of spread footings on natural soils and aggregate piers, and a mat foundation for support of the new buildings. The existing tower is supported on drilled shaft caissons.
Eric Colbert & Associates is the project architect and Donohoe Construction Company is the general contractor.
Renderings courtesy of JBG Smith
Dynamic renovations of the 175,000-square-foot 1441 L Street office building encompass the addition of two new levels of office space and an occupiable penthouse to the top floor. When completed in late 2018, the 30-year-old structure will be larger by 35,500 square feet.
During design, we were engaged to review available subsurface data and assess the capability of the existing spread footings to support the altered structural loads resulting from the new levels. As construction geared up, we conducted a supplemental geotechnical investigation to evaluate support of the crane pad to be installed at street grade. Due to relatively deep soft and loose fill material, the presence of existing utilities, and non-reinforced below-grade walls, we recommended supporting the pad on auger cast pile foundations.
Renderings courtesy of DEP Designs and ArchiBIM
With thriving Capitol Riverfront and Southwest Waterfront neighborhood developments underway, Pepco’s Waterfront Substation 223 in Buzzard Point was constructed to meet the anticipated electrical usage demands of customers. Construction on the four-acre site consisted of a 93,419-square-foot substation, as well as phase shifter yard. The design-build project, which was completed December 2017, was awarded to Coakley Williams Construction. MGMA was the architect.
In our role as geotechnical engineer, we worked directly with Coakley Williams and their joint venture partner ABB to provide extensive subsurface exploration, foundation design, and construction administration services. Strict settlement requirements and varying subsurface conditions resulted in the structure being founded on a combination of auger cast piles, traditional spread footings, and spread footings founded on compacted aggregate piers.
Completed project images © Jason Flakes
Located near Dupont Circle, 1789 Massachusetts Avenue NW is a national historic landmark built in 1917. It originally served as a luxury apartment building and home to Andrew Mellon, a wealthy financier, philanthropist and politician. In 2013, the National Trust for Historic Preservation sold the five-story building to the American Enterprise Institute for Public Policy Research, a think tank that would occupy the property as its new headquarters after a $40 million renovation.
The ambitious project scope involved the excavation, underpinning and construction of a new 28,000-square-foot level below the existing basement, construction of a new central core, and reinforcement of the steel structure to accommodate the addition of a penthouse with balcony views of the neighborhood.
SEDC was responsible for the subsurface investigation, consisting of obtaining drilling permits, drilling borings, excavation of two interior test pits, and preparation of a geotechnical report. Along with new spread footings, we also recommended underpinning with traditional hand-dug piers and with micropiles. This solution supported existing structural elements while preserving the physical character of the historic building.
During construction, SEDC provided full-time construction inspection and materials testing, to observe the proper installation of the improved foundation system, earthwork, sub-drainage system, and waterproofing.
The Brendan Iribe Center at University of Maryland’s College Park campus is a unifying force at the corner of Baltimore Avenue and Campus Drive. It brings together under one roof the Department of Computer Science and the Institute for Advanced Computer Studies and the more than 2,300 constituent students whose classes were scattered amongst four buildings.
Named for major donor Brendan Iribe of Oculus VR, the six-story, 215,600-square-foot building designed by HDR, Inc. is a technology hub at the heart of a new innovation district that connects high-tech companies, government agencies and institutional colleagues. It houses specialized labs which support groundbreaking research in virtual and augmented reality, artificial intelligence, robotics, computer vision, algorithms and programming languages and systems.
SEDC was initially charged with determining geotechnical characteristics of the site and providing recommendations for foundations and related earthwork. The ensuing subsurface exploration encompassed soil borings, laboratory testing and a report. As design progressed, our scope expanded to include a geophysical investigation to determine shear wave velocities; additional borings for design of an associated parking lot, fire lane, and new mechanical systems for the center. Infiltration testing was also conducted to aid in stormwater management design.
Our services have continued through construction, during which we are providing observation and materials testing for sheeting and shoring, foundations, and earthwork. The building is slated for substantial completion in time for the fall 2018 semester.
Renderings © HDR
Arizona State University (ASU), which had rented space in the area since 2010, wished to establish a permanent presence in downtown Washington, D.C. After a lengthy search for the right building in a desirable location, they purchased 1800 I Street NW, two blocks from the White House. In March 2018, following a $35 million renovation, the doors to the eight-story, 32,000-square-foot Barrett and O’Connor Center opened. Named for noteworthy female Republican Arizonans, Ambassador Barbara Barrett and former U.S. Supreme Court Justice Sandra Day O’Connor, the center is home for programs in four ASU schools, multiple think tanks, a policy journal, lobbying operations, and collaborative ventures with other organizations.
Modifications to the historic building consisted of expanding the below-grade level, adding a ninth floor, and comprehensive interior renovations. SEDC provided geotechnical engineering, construction observation and materials testing services on the project. The historic nature of the building dictated careful protection of the façade while gutting the interior of the building. Our geotechnical engineering recommendations addressed new and existing structural elements, which included spread footings, micropiles and underpinning with a combination of traditional hand-dug piers and micropiles.
During construction, we observed the installation of micropiles, earthwork and foundations (spread footings and wall footings), underpinning pits, cast-in-place concrete, masonry prisms, and Windsor probe testing.
Photos © Arizona State University
The six-story, 121,000 square foot Unisphere represents the third phase of the expansion of United Therapeutics’ (UT) headquarters. When completed in 2018, it will increase office space, add structured parking and 10,000 square feet of retail, and connect directly to UT’s laboratory. The building was designed by EwingCole’s multi-disciplinary team to operate as a net zero site, and LEED certification with the U.S. Green Building Council is in progress.
UT had worked with Schnabel Engineering and later SEDC on several projects over the past 10 years, including the 2013 geotechnical engineering report for this project. Due to this established relationship and our knowledge of the subsoil characteristics of the site and Montgomery County’s Special Inspections program, UT hired us to provide observation and testing services in support of construction by Whiting-Turner. Our involvement encompasses detailed tasks within the major construction activities of sheeting and shoring; shallow foundations and drilled shaft foundations; cast-in-place concrete for foundations; and general earthwork.
Rendering courtesy of EwingCole.
The USDA Southwest Watershed Research Center is more than 30 years old and several research departments occupy multiple small buildings. A study was conducted to evaluate modernizing the facility by consolidating several of the work spaces under one roof. The result is a new 15,000-square-foot, single-story, slab-on-grade laboratory building. Buildings 102, 111, 302, 303 and 312 will be demolished to make way for the structure.
Also proposed is a one- or two-story, 22,000-square-foot storage facility to be located at an undeveloped 7.1-acre site in Tombstone. Planned surface parking will increase the future development footprint to about 60,000 square feet.
Under an IDIQ contract held by AECOM, we conducted subsurface explorations to identify the stratigraphy underlying each site and evaluated the geotechnical properties of the materials encountered. Special consideration was given to the proximity of the borings to the bee laboratory in Tucson and challenging terrain was faced in Tombstone. We also provided recommendations for support of the proposed buildings via spread footings, floor slab support, earthwork and pavement.
The District’s Department of General Services (DGS) conducted a months-long search to identify suitable sites for the new short-term family housing that would accommodate up to 50 families. DGS looked for spaces that could collectively serve the same number of residents at DC General, with access to services and public transportation. The selected site for one of the new shelters is in Ward 3 at 3320 Idaho Avenue, NW.
The proposed shelter shares a site with the Metropolitan Police Department’s Second District station. Designed by Ayers Saint Gross, the six-story building will be sectioned off from the police station and houses to the south with fencing. A new multilevel parking structure will be built along the rear of the police department so officers can continue to park their vehicles on site. A playground will be located between the new shelter and neighborhood homes.
As the geotechnical engineer, we performed a subsurface investigation requiring soil borings and test pits in order to determine the most appropriate foundation for the shelter and parking structure. After analyzing the data, we recommended a spread footing foundation on compacted aggregate piers or auger cast piles. Our report also addressed floor slabs, earthwork, below-grade walls and retaining walls, sub-drainage, and temporary sheeting and shoring. SEDC is also providing limited services during the construction documents and construction administration phases of the project.
Rendering courtesy of Ayers Saint Gross
The International Spy Museum (SPY) is the only public museum in the United States solely dedicated to the tradecraft, history, and contemporary role of espionage and intelligence. Open since July 2002, it features the largest collection of international espionage artifacts ever placed on public display. In 2018, the museum will relocate eight blocks south to L’Enfant Plaza, inhabiting a new $50 million building which will serve as a catalyst for transformation for SPY, the immediate neighborhood, and the Southwest Ecodistrict. The Malrite Company and The JBG Companies collaborated on plans for the 140,000 square foot facility, which will sit directly in front of the glass atrium on the Plaza.
Proposed construction increased the column loads on the Plaza by up to 2,800 kips, which necessitated retrofitting the existing foundation. SEDC’s parent company, Schnabel Engineering, was hired by JBG to work with the structural engineer, SK&A, on the retrofit design. Schnabel’s solution was to install micropiles through the existing footings, thus increasing the vertical load capacity from 1,000 to 1,800 kips. SEDC was hired to provide the construction observation oversight during the micropile load test, installation of the micropiles, earthwork, and cast-in-place concrete and grout for the foundations.
Renderings courtesy of Rogers Stirk Harbour + Partners
