One Light Street
Structural | Commercial, Mixed-use
Structural
Commercial, Mixed-use
Project Overview
One Light Street is a 776,000 square foot, 28-story mixed-use building in downtown Baltimore and the first mixed-use skyscraper in the city. The building features 9 levels of office space, 10 levels of residential space totaling 280 units, 7 levels of above-grade parking, 2 levels of below-grade parking, and ground-level retail. The project boasts floor-to-ceiling curtain wall windows on each floor of the building, with the silver glass of the façade giving the building a sleek, uniform look designed to reflect the sky and historic space of Downtown Baltimore. In addition to the base building project, Donohoe also built out the interior office space for M&T Bank, the anchor tenant of the building. One Light Street is LEED Silver Certified.
If you’ve ever visited the city of Baltimore, you may have noticed the pleasant, history-infused atmosphere of “Charm City.” But only when constructing a concrete tower near the Inner Harbor can you truly appreciate the challenges of building in this historic seaport city.
Since early 2017, the Baker team has navigated numerous obstacles to help construct the One Light Street project. This 28-story mixed-use tower will combine luxury residential apartments, Class-A office space, and 5,000 square feet of ground floor retail space. The project is expected to play a major role in the ongoing renaissance of downtown Baltimore’s core.
Client
Donohoe Construction Company
Location
Baltimore, MD
Size
40,000 CY
Completion
August 2018
Additional Information
One Light is situated across from three of the city’s tallest buildings: the 1920s-era Bank of America tower (509 feet), the William Donald Schaefer Building (493 feet), and the Wells Fargo Building (330 feet). The eight-story Thomas Building, constructed just after the Great Fire of 1904 destroyed much of downtown Baltimore, shares the block.
One Light also happens to be located between Baltimore and Light streets, two of the city’s busiest arteries for vehicle travel. With the height of the neighboring buildings and the constraints of massive underground utilities and Baltimore’s Metro, the first obstacle we faced was having to switch from a flat-top tower crane to a luffing tower. In March 2017, Baker began placing the first of 40,000 cubic yards of concrete.
Among the many challenges we overcame during the early phases – Resequencing our work to mitigate excavation, Shoring constraints and delaying subgrade turnovers, Redesigning and finding workarounds to combat the underpinning and stabilization of the Thomas Building structure.
Driving the schedule-By combining knowledge and standard practices, Baker co-workers partnered with our client to create a new project flow so operations could continue. As the mat foundation went in, vertical work went up. In May, Baker was able to catch our flow, and week by week, progress to the top became visible. After working through the upfront troubles, Baker and our client developed new schedule milestones and we took off running.
From three garage levels below grade, Baker reached our first milestone; completing the eight levels of above-grade parking on schedule in October. With its sloped ramps and wide, end-to-end post-tension beams, the 26,000-square-foot parking area went smoothly—thanks to consistent and detailed planning, utilization of perimeter tables, and dedication of our co-workers.
In transition-With the garage portion complete, we headed right into our first building transition, which took our typical 10-foot, 4-inch garage levels through to the 15-foot, 4-inch 9th floor (to be converted from garage to office space). To make this transition, we had to slightly modify our practices and rhythm of sloped garage decks to more typical deck and beam post-tension decks. But our co-workers took this transition in stride, maintaining durations and dates to our next transition at level 18.
As we drew closer to the next milestone, Baker co-workers continued diligently through while completing the construction of three elevator cores (roughly 30 x 30-foot each). Utilizing Ulma 3 tiered self-climbing systems inside, the team maintained our 2-day cycle of jacking, setting, and pouring these cores in advance of our deck cycle.
Level 18 proved just as tough as we’d anticipated. With a 20-foot, 4-inch floor height and a series of 6-foot wide and 5-foot deep beams, on the first of our elevated stepped courtyard areas, we had a total of nine interrupted days of production due to inclement weather. All these factors made it difficult to transition seamlessly into and through this floor. But once again, the dedicated, hardworking and talented craft workers of Baker rose to the occasion, and we forged ahead.
Battle against time-When the dust of the 18th level settled, we quickly found ourselves faced with constructing levels 19 to 27 with more standard flat soffit post-tension floors. Since our May revisit of the schedule with our client, plus other issues and significant weather delays, Baker remained neck-in-neck with that May schedule from nearly a year prior.
Final stage-Currently, Baker is gearing up to construct the final 28th floor, followed by a large cast-in-place equipment platform level. This level spans fully across the buildings, north to south, stepping back in width from east and west. Upon closing the structural scope, we will reach the top with the high roof level, which stands nearly 30 feet higher to our east. The team will create a final cast-in-place deck slab requiring a 10-foot slope over the 40-foot width.
Despite all the curveballs, the One Light Street project emerges as another Baker win, built on a solid foundation of process, diligent and detailed estimates, pre-construction, pre-planning, engineering, and our daily on-site efforts. Most importantly, our success comes directly from the dedication, skills, and knowledge our co-workers gave to this project. We appreciate you and a job well done!