The project: The new mixed-use development includes approximately 140,000-sf of office space and 12,400-sf of retail and a 280-space double-level underground parking garage. The project also preserved a historic post office.

The goal: Preserve the historic 1940s Spanish eclectic post office within the surrounding new mixed-use development.

Challenge: Rather than shoring the post office in place to excavate and construct the basement levels for the underground parking garage, the design team decided to relocate the historic post office. Solution: A temporary structural support system with concrete piers and steel beams was used to temporarily relocate the 1,010-ton historic building. The historic wings to remain were separated using diamond-tipped concrete saws, then hydraulic jacks raised the structure, which was then placed onto steel beams that allowed the structure to be moved off site. After the construction of the basement, the historic building was moved back to its intended location where it is now supported by new reinforced concrete transfer beams.

Challenge: Detailing connections between the relocated historic structure and new building, particularly for transferring lateral seismic forces, as the historic concrete presented limited opportunities for creating robust connections without compromising original integrity. Solution: Engineers developed specialized connection details to effectively transfer seismic forces into the new podium while remaining visually unobtrusive and respecting the preservation requirements. The transfer beam grid supporting the historic building was designed to seamlessly integrate with both structures, creating a structural transition zone that accommodates different behaviors while maintaining the architectural integrity of the historic elements and providing a robust foundation.

Challenge: Architectural constraints limited wall placement options, dictating shear wall locations to preserve aesthetic and functional aspects of the design. Solution: The structural team countered torsional behavior under lateral loads by strategically oversizing specific shear walls to balance stiffness across the asymmetrical lateral support placement.

The outcome: The project honors the post office’s historic significance while providing flexible and modern office and retail space, creating a vibrant connection between Burlingame’s past and future.