Project Spotlight: The Alexander

Bridging the gap between Center City and North Philadelphia, The Alexander plays an important role in the North Broad Renaissance. The luxury residential building and mixed-use development is located on Vine Street adjacent to the new Mormon Temple, just blocks away from Center City.

North Philadelphia is experiencing a major revitalization as community stakeholders and businesses reinvest in the neighborhood. This movement has led to an increase in housing and mixed-use developments in the area, including the restoration of The Divine Lorraine Hotel and the opening of Hanover North Broad. The Alexander adds to the momentum of the revitalization, providing the community with luxury residential units and retail.

Project Specs:

  • Square Feet: 483,000 sf
  • Stories: 34
  • Units: 264 rental apartments ranging from studios to four-bedroom townhomes
  • Amenities: Indoor swimming pool, six green roofs, an observation deck and amenities terrace, fitness and business centers, three levels of underground parking
  • Architect: Robert A.M. Stern Architects and BLT Architects

Named after Alexander Calder, the Philadelphia sculptor who created the infamous William Penn statue on top of City Hall, The Alexander offers sweeping views of the Center City skyline, with many of the units featuring outdoor balconies or wrap-around terraces.

The Harman Group served as the structural engineer on this project. A 31-story residential cast-in-place concrete tower sits on a three-story podium and three levels of post-tensioned underground parking, totaling 140,000 square feet. The podium includes 13 three-story townhouses and ground floor retail space, which is now occupied by The Learning Experience, an early education academy for children six weeks to six years old. The childcare center is open to all families living and working in the area.

Biggest project hurdle to overcome:

Due to hydrostatic pressures from a shallow ground water table, the project team had to design the basement levels as a bathtub construction with rock anchors.

Interesting structural features:

To accommodate the building’s different uses at different levels, sloping columns, 5 ½ -foot-deep transfer girders and 20 to 36” transfer slabs were used to align different column grids between the stacked residential, amenities, retail and parking layouts.

Post-tensioning was utilized in parking level slabs for additional durability and tower floors at the slab edges to stiffen for heavy loading due to pre-cast facade elements.