The University of Pennsylvania boathouse is a historically registered Philadelphia landmark, originally dating back to 1874 with east & west additions constructed in 1930 and 1980. Following a feasibility study, the design team moved forward with the demolition and subsequent addition of the building’s 1930 east bay and a Level 3 alteration of the existing building. The addition consisted of a concrete podium supporting a steel superstructure. The addition was laterally isolated from the existing structure and founded on deep, helical pile foundations. The existing building alteration consisted of raising the entire 2nd floor of the original 1874 bay, introducing an elevator, and demolishing a portion of 2nd floor framing to create an open two-story vestibule. Numerous constraints and project objectives guided the structural system towards its final form.
1. Maximizing boat storage: The 1st floor serves as storage for the boats. The goal was to maximize the floor-to-ceiling height. The 2nd floor elevation was constrained to match the historic 1930 elevation of the boathouse per the historic commission. A one-way concrete slab podium was selected to minimize structural depth to 8” thick. The slab clear spans 20’-7”, which triggered the need to analyze deflections per ACI. All supporting concrete beams were oriented to run parallel to the boat storage to maximize storage height. 6000psi concrete was specified with 40% slag content. Type IL cement was used.
2. Open Event Space/Erg Room: The second floor of the addition featured an open space that would serve as a training room or potential event space. The concrete podium supports the assembly loading. A steel superstructure springs up from the concrete podium to accommodate the desired open space. Rigid HSS bent frames were designed to create the gable profiles that hosted skylights. The exposed form of an inverted king-post truss was selected to clear span 45’-0” and support the sawtooth roof framing with minimal column supports. A 32’-0” portal opening was also created riverside with strict deflection limitations for a Nanawall system that opens to a balcony and river overlook. For a cleaner aesthetic of the exposed steel column bases, embed plates were cast into the podium and used in lieu of traditional anchor rods and base plates. Flange and web plates secured the column bases.
3. Site Conditions: The site is classified as Site Class E and located within a flood zone. Helical piles were recommended by the geotechnical engineer for deep foundations. The site is confined between adjacent boathouses. The concrete podium columns landed near the edge of the pile caps. Grade beams were designed to resolve the pile cap eccentricity and distribute the load to the helical piles. All new structure introduced below the design flood elevation was concrete for improved durability against flood events and the constant exposure to a river environment. This includes a perimeter curb wall around the addition in which flood vents were installed. CMU was used above the flood elevation.
4. Floor Elevations/ADA: The two historic additions to the boathouse each have unique 2nd floor elevations that differ from the original 1874 building. The 2nd floor wood framing of the 1874 building was replaced with new structure at an elevation to match the addition. Sequenced construction and temporary bracing were required to maintain the stability of the rubble stone walls throughout construction. An elevator shaft for a LULA was designed adjacent to the original boathouse chimney to facilitate ADA access.
5. Entry Vestibule: Entering from Kelly Drive, the original 2nd floor was demolished to create a two-story entry vestibule. This allowed the original chimney and roof rafters to become exposed. The existing exterior wood stud walls required bracing where the elevated floor framing was demolished. Four HSS posts were knitted between existing wood studs and tied together with channels that wrap the vestibule at the 2nd floor elevation. The steel hides behind the bead board finish and serves to brace the wood studs and preserve the original wood structure. The entry vestibule also included a feature stair with floating treads cantilevering from a single, central stringer.
6. Balconies & Thermal Bridging: Three riverside balconies were introduced through the project, one in each bay of the boathouse. The center balcony is mounted with brackets to the original rubble stone wall. The east bay addition balcony is supported by the concrete podium. A Schoeck Thermal Break was specified within the podium slab at the exterior wall to curtail thermal losses where the concrete transitions from exterior to interior.
7. Existing Building Repairs: The existing rubble stone walls of the boathouse were repointed with ribbon cut pointing similar to the original. Numerous existing deficiencies were repaired during construction, including Cintec anchors in the rubble stone walls, flitch plates to preserve the historic roof rafters, and rot repair of existing wood studs.
The University of Pennsylvania boathouse is a historically registered Philadelphia landmark, originally dating back to 1874 with east & west additions constructed in 1930 and 1980. Following a feasibility study, the design team moved forward with the demolition and subsequent addition of the building’s 1930 east bay and a Level 3 alteration of the existing building. The addition consisted of a concrete podium supporting a steel superstructure. The addition was laterally isolated from the existing structure and founded on deep, helical pile foundations. The existing building alteration consisted of raising the entire 2nd floor of the original 1874 bay, introducing an elevator, and demolishing a portion of 2nd floor framing to create an open two-story vestibule. Numerous constraints and project objectives guided the structural system towards its final form.
1. Maximizing boat storage: The 1st floor serves as storage for the boats. The goal was to maximize the floor-to-ceiling height. The 2nd floor elevation was constrained to match the historic 1930 elevation of the boathouse per the historic commission. A one-way concrete slab podium was selected to minimize structural depth to 8” thick. The slab clear spans 20’-7”, which triggered the need to analyze deflections per ACI. All supporting concrete beams were oriented to run parallel to the boat storage to maximize storage height. 6000psi concrete was specified with 40% slag content. Type IL cement was used.
2. Open Event Space/Erg Room: The second floor of the addition featured an open space that would serve as a training room or potential event space. The concrete podium supports the assembly loading. A steel superstructure springs up from the concrete podium to accommodate the desired open space. Rigid HSS bent frames were designed to create the gable profiles that hosted skylights. The exposed form of an inverted king-post truss was selected to clear span 45’-0” and support the sawtooth roof framing with minimal column supports. A 32’-0” portal opening was also created riverside with strict deflection limitations for a Nanawall system that opens to a balcony and river overlook. For a cleaner aesthetic of the exposed steel column bases, embed plates were cast into the podium and used in lieu of traditional anchor rods and base plates. Flange and web plates secured the column bases.
3. Site Conditions: The site is classified as Site Class E and located within a flood zone. Helical piles were recommended by the geotechnical engineer for deep foundations. The site is confined between adjacent boathouses. The concrete podium columns landed near the edge of the pile caps. Grade beams were designed to resolve the pile cap eccentricity and distribute the load to the helical piles. All new structure introduced below the design flood elevation was concrete for improved durability against flood events and the constant exposure to a river environment. This includes a perimeter curb wall around the addition in which flood vents were installed. CMU was used above the flood elevation.
4. Floor Elevations/ADA: The two historic additions to the boathouse each have unique 2nd floor elevations that differ from the original 1874 building. The 2nd floor wood framing of the 1874 building was replaced with new structure at an elevation to match the addition. Sequenced construction and temporary bracing were required to maintain the stability of the rubble stone walls throughout construction. An elevator shaft for a LULA was designed adjacent to the original boathouse chimney to facilitate ADA access.
5. Entry Vestibule: Entering from Kelly Drive, the original 2nd floor was demolished to create a two-story entry vestibule. This allowed the original chimney and roof rafters to become exposed. The existing exterior wood stud walls required bracing where the elevated floor framing was demolished. Four HSS posts were knitted between existing wood studs and tied together with channels that wrap the vestibule at the 2nd floor elevation. The steel hides behind the bead board finish and serves to brace the wood studs and preserve the original wood structure. The entry vestibule also included a feature stair with floating treads cantilevering from a single, central stringer.
6. Balconies & Thermal Bridging: Three riverside balconies were introduced through the project, one in each bay of the boathouse. The center balcony is mounted with brackets to the original rubble stone wall. The east bay addition balcony is supported by the concrete podium. A Schoeck Thermal Break was specified within the podium slab at the exterior wall to curtail thermal losses where the concrete transitions from exterior to interior.
7. Existing Building Repairs: The existing rubble stone walls of the boathouse were repointed with ribbon cut pointing similar to the original. Numerous existing deficiencies were repaired during construction, including Cintec anchors in the rubble stone walls, flitch plates to preserve the historic roof rafters, and rot repair of existing wood studs.
CLIENT: Ewing Cole
LOCATION: Philadelphia, PA
TYPE: Academic, Athletic, SERVICES: Addition, Renovation, MATERIALS: SUSTAINABILITY: . . . . . . . . . . . . . . . . . . . . . . . .
Final Photography ©HalkinMason
