The villas, built in 1936 as Surfside, FL’s first beachfront apartment house, earned designation as a historically significant building in 2014. This three-story, Mediterranean-inspired landmark spans approximately 10,800 square feet, featuring wood floors supported by load-bearing CMU walls and reinforced concrete frames. In June 2021, this historic structure underwent comprehensive redevelopment, including selective demolition, repair, strengthening, relocation, and new construction. Due to its designation as a local historic site, a significant part of the exterior façade fronting the U-shaped structure was preserved and integrated into the new $200 million residences project, an exclusive luxury oceanfront development. Construction of the main building frame was substantially completed in the fall of 2023.

Preservation and Redevelopment Strategy

Due to its status as a local historic site, preserving the exterior façade of the structure was paramount. To comply with the preservation of historical sites and architectural area local codes without limiting the new development adjacent to this structure, the structural engineers and specialized restoration teams were required to devise an innovative solution that addresses several structural challenges and a robust repair and redesign strategy. The project aimed to blend historic preservation with modern luxury while maintaining the building's integrity and value. To protect the building during the construction of a new below-grade parking garage and basement, the structure was temporarily relocated.

Structural Challenges and Solutions

The historic 3-story structure plus roof measured 90 feet by 30 feet in plan and weighed just over one million pounds. The building exhibited substantial structural deterioration and decay due to its age and exposure to the harsh ocean environment, which damaged the CMU, wood-framed floors, and reinforced concrete beams and columns. To address this, the design-build team devised a two-pronged strategy – the first was to restore and strengthen the historic facade that was to be preserved as part of the new development, and the second was to demolish and reconstruct the structural elements that were beyond repair. A demolition plan was implemented to tear down the two wings of the structure that were not designated as historic and carefully remove the interior structural elements of the main building while preserving its façade, chimneys, and exterior walls. The demolition of the building's interior began in June 2021 and included the roof, wood floors, concrete beams, and CMU walls, creating space for a new concrete frame consisting of cast-in-place (CIP) columns integrated with the existing CMU walls and new permanent elevated hybrid PT slabs. The new concrete frame was constructed using the form-and-place method, with the new columns and slabs doweled into the existing façade CMU. New reinforced concrete columns were constructed integrally into the historic building facade. A new hybrid flat-plate slab system was used for the elevated floors, which incorporated post-tensioning (PT) in the east-west direction and conventional reinforcement in the north-south direction. The design team decided on PT in the east-west direction to minimize slab thickness and allow for maximum floor-to-ceiling heights. PT was not feasible in the north-south direction as stressing would have required partial destruction of the historic facade. Construction of the new concrete frame did not begin until late 2022 after the building had been relocated to its final position.

Restoration and Strengthening of Historic Facade

The historic façade, combining CMU and reinforced concrete beams and columns, needed to be repaired and strengthened to meet modern building code requirements. The original columns, constructed in the 1930s, no longer complied with modern building codes. Florida’s statewide building code now requires reinforced concrete and CMU that make up the facade to withstand extreme wind events caused by hurricanes that often batter the area. Additionally, years of exposure to the harsh beach environment led to corrosion of the embedded reinforcing steel, causing concrete spalling and delamination and further weakening the walls.

To address these challenges, the historic CMU walls were repaired and strengthened, and the concrete frame was repaired using conventional concrete repair methods. The CMU was strengthened by adding a reinforcing bar in every other cell and filling those cells solid with high-strength grout. The concrete frame was repaired using chipping hammers for demolition, preparing the surface to a saturated surface-dry (SSD) condition, and forming and placing new repair mortar. Scaffolding and shoring were installed to support the structure during the repair and strengthening process. The chimneys, earmarked for preservation, were carefully encased in temporary steel frames and lifted off the building for safekeeping – to be reattached after building relocation and new roof construction was complete. The roof was removed, and a temporary steel bracing framework was installed to support the façade and prevent damage during the building relocation. This intricate engineering strategy preserved the villas' legacy, ensuring the historic structure could meet contemporary demands for upscale oceanfront living while maintaining its storied past.

Relocation of the building’s facade

Following the initial demolition and strengthening of the historic CMU and concrete façade, the preserved structure needed to be temporarily moved approximately 150 feet south. This relocation was essential to facilitate the construction of a below-grade parking garage, complete with auger cast piles, pile cap foundations, and a basement.

In a collaborative design-build effort, the teams worked together to brace the building shell and develop a skidding system to move the building in one piece. It was critical that the facade be moved in three phases without damaging the historic structure. Prior to the demolition of the building’s interior, the facade was braced on the interior using a structural steel bracing frame. Needle beams were inserted using a crane through the east and west facades and attached to the building using a temporary CIP ring beam to help stiffen the structure throughout the move. Skidding rails were installed over temporary CIP post-tensioned grade beams that were set in the ground on both sides of the building. The trenches were manually dug due to space constraints. A system of vertical hydraulic cylinders placed on the grade beams was used to lift the building from the needle beams, allowing for a clean cut without pinching the concrete saw. The building was then lowered onto skid beams, and a conveyor system was placed atop wood blocks, preparing it for relocation. Once the building was lifted, a low-profile skidding system was inserted under it, with ten skid shoe beams and 98 pieces of skid track forming a 120-foot runway on the east and west sides. This setup saved significant time and labor costs by reducing the need to leapfrog the track to reach the destination. Using four push-pull units, the structure was moved over three days. The structure was lifted and moved in three phases until it reached its final location.

With the new construction brought up to grade, the historic building was repositioned to its final resting place, approximately 12 feet east of its original location. Now elevated above a one-story underground garage, this final relocation enabled the seamless integration of the new 11-story luxury condo with the historic villa’s façade.

Design Build Strategy Integrates Historic with The Modern

Preserving this 85-year-old historic building not only enhances the character and sense of community in Surfside but also safeguards its history. This innovative project, requiring considerable skill and expertise, involved the restoration of reinforced concrete and CMU that had undergone considerable deterioration over time and did not meet stringent modern building codes. The building's temporary relocation to a staging area allowed for the construction of the below-grade parking level, after which it was moved back to its permanent location on top of the Level 1 slab. Finally, the replacement of the interior floors and old load-bearing walls and columns with new hybrid PT framing while seamlessly integrating with the new luxury development makes this project truly worthy of recognition.