Structures / 3130 Wilshire Retrofit

• Tipping Structural Engineers

As a non-ductile concrete structure, 3130 Wilshire was subject to the Mandatory Santa Monica Non-ductile Concrete Ordinance, passed in 2017. With its distinctive mid-century design, the building’s lateral system does not resemble the layout or proportions common in modern buildings. However, the key to this project’s success lies in recognizing that the original construction of repetitive exterior concrete fins creates a robust and ductile seismic system in need of only localized improvements.

The previous retrofit scheme, which we presume was based on a linear analysis, utilized an extensive amount of FRP wrapping throughout the interior of the building as well as multiple new full-height steel frames. An alternate solution that would be less disruptive, avoid tenant displacement, provide significant cost savings, and mitigate impacts to the building space plan, window placement, and views was a compelling prospect.

Tipping’s proposed retrofit adopted a more strategic and targeted approach, harvesting the inherent strength of the structure, while ensuring the building’s overall seismic performance was not compromised and the requirements of the Non-ductile Concrete Ordinance were satisfied.

The SEAONC Jury for the 2025 SEE awards described their innovative approach:

“The retrofit [developed by Tipping] … overcame complex engineering challenges by replacing the disruptive, costly, linear analysis based solution with a more strategic performance-based approach using nonlinear analysis. The result was a tailored code-compliant seismic upgrade that not only preserved the building’s function and aesthetic but also reduced projected retrofit costs… exemplifying structural engineering excellence through innovation and resilience. Judges were impressed by the minimal impact to tenants, considering the significant amount of work required to retrofit the structure. They also commented on the efficiency of reducing the soft story potential at the lower level.”

3130 Wilshire was constructed in 1968 and considered a non-ductile concrete building. The building’s gravity system consisted of a slab and joist system spanning to four girder lines. On the upper floors, an array of exterior fin columns supported the exterior girders, while interior girders were supported by square columns. At the first floor, these fin columns were transferred by a girder at level two, with discreet columns supporting the transfer girder. The basement perimeter was enclosed with concrete walls.

• 2025 SEAONC Structural Engineering Excellence, Award of Merit, Retrofit Category
• 2025 NCSEA Structural Engineering Excellence Award Finalist, Forensic/Retrofit/Rehabilitation (winner announced Oct 16, 2025 at conference in NYC)

• Tipping Project Page: 3130 Wilshire