The Engineering Beneath Boston University’s Jenga Tower

On Commonwealth Avenue, Boston University’s computing and data sciences tower looks like someone paused halfway through rearranging a stack of books. Glass volumes project beyond the floors below, leaving pockets of open sky between them. The silhouette invites a question: how does all that weight stay up?

The answer involves steel erected slightly higher than its eventual position, temporary supports released with hydraulic jacks, and a foundation designed around Boston’s difficult soil. But the tower’s other engineering story reaches much farther down. Its heating and cooling system exchanges heat with bedrock through boreholes extending 1,500 feet underground.

Together, those systems make the building a useful lesson in architecture: the most conspicuous design decisions often depend on work that disappears from view.

A campus stacked vertically

Designed by Toronto-based KPMB Architects, the Duan Family Center for Computing & Data Sciences occupies a compact site near the Charles River. Completed in 2022, the 19-story, 345,000-square-foot building brings students, researchers, and faculty into a shared vertical campus. Its program gathers mathematics, computer science, and data sciences around places intended for conversation as well as concentrated work. KPMB’s project account

The shifting blocks give that large institution a more intimate scale. KPMB describes the volumes as a response to neighboring buildings of two and three stories, with individual departments gaining recognizable identities and outdoor terraces. Where one volume pulls back, the roof below becomes usable space. Eight planted terraces carry that idea up the building.

Inside, a five-story atrium, connecting stairs, classrooms, and shared work areas extend the same social ambition. The architecture creates opportunities to encounter another discipline without scheduling a formal meeting. A terrace or stair landing can become part of academic life, alongside the office and classroom. That is the practical purpose behind the tower’s seemingly restless outline. KPMB

Building in an allowance for gravity

The structure had to reconcile those overhangs with a demanding site. Beneath the reclaimed land lies a thick layer of marine clay. Engineers limited building weight to control settlement, using a mat foundation, a slender concrete core, and lightweight floor construction.

The floor plates shift by one 23-foot structural bay every two or three stories. Two-story steel trusses carry the projecting volumes and transfer their loads toward columns continuing through the tower. Some floors are supported from below; others hang from the structure above.

Steel deflects under weight. To account for that movement, engineers specified an upward adjustment equal to 80 percent of the predicted deflection from permanent loads. Temporary shoring supported construction, and hydraulic jacks allowed crews to transfer weight into the cantilever framing gradually.

Gravity therefore completed a movement anticipated in the design. The raised starting position compensated for much of the expected downward displacement. This was a calculated construction sequence, with the eventual geometry considered before the supports came away. Structural engineer Nathan C. Roy details the system in STRUCTURE magazine.

The deeper construction puzzle

Below ground, another team faced a different space problem: how to fit a substantial geothermal installation into a dense urban setting.

Haley & Aldrich, responsible for geothermal and geotechnical design, selected concentric ground-source heat exchangers capable of reaching 1,500 feet into the underlying rock. Getting there required more than choosing a drilling depth. The team worked with drilling contractors to test installation methods, limit borehole deviation, and control groundwater entering the holes during construction. Those trials informed the completed installation by Skillings & Sons. Haley & Aldrich’s engineering account

That testing matters because the underground portion becomes permanent infrastructure. Once the building is occupied, its occupants experience comfortable rooms rather than the drilling decisions that made them possible. The finished system conceals a substantial exercise in geology, equipment selection, and construction planning.

Moving heat through the seasons

The geothermal system takes advantage of temperatures that fluctuate much less underground than they do in Boston’s air. During preliminary drilling in 2019, BU described temperatures at the proposed 1,500-foot depth as typically between 50 and 60 degrees Fahrenheit. That provides a useful thermal resource through both winter cold and summer heat. BU’s account of the test drilling

A closed piping loop circulates fluid to exchange heat with the ground. In winter, the system extracts underground heat, and heat pumps make it useful for warming the building. In summer, the direction of heat transfer reverses: unwanted indoor heat travels into the ground. The same buried infrastructure serves both seasons.

The crucial distinction is that the boreholes exchange heat. They are not an underground electricity plant. Pumps and building equipment still require electrical power, while the ground supplies a relatively stable place to collect or release thermal energy.

BU reports that the 31 boreholes provide 90 percent of the building’s heating and cooling capacity. Electric boilers and chillers supply the remaining capacity. That figure describes the thermal system’s contribution, rather than a claim that the ground supplies 90 percent of every form of energy consumed inside. BU Sustainability’s opening report

Making the demand smaller

The building also reduces the work asked of its mechanical systems. Fixed exterior shades limit direct solar heat, while triple-glazed windows help resist heat transfer through the facade. These measures address the load before equipment has to meet it. BU connected the project to its broader goal of net-zero university carbon emissions by 2040. BU Today’s building overview

There is no gas connection, including for food preparation. BU also explains that electricity consumption is matched through its renewable energy arrangements, including renewable energy certificates associated with BU Wind. That accounting belongs alongside the geothermal system when describing the building’s carbon strategy. BU Sustainability

From the street, the cantilevers remain the attraction. They turn a university building into a skyline puzzle. Yet the fuller achievement connects those visible gestures to quieter decisions: allowing for structural movement, investigating the rock, reducing heat loss, and providing electric backup. The tower rewards looking up. Understanding it requires looking below the pavement, too.

Sources

• KPMB Architects: Duan Family Center for Computing & Data Sciences
• STRUCTURE: Boston University, by Nathan C. Roy
• Haley & Aldrich: Geothermal system design and construction
• BU Today: Historic, and Loud, Geothermal Drilling Gets Underway
• BU Sustainability: The Opening of the Center for Computing & Data Sciences
• BU Today: No Gas. No Fuels. No Emissions. BU’s Greenest Building Ever