Design Architect:

LPA Design Studios

Associate Architect or Firm:

LPA Design Studios

Landscape Architect:

Owner / Developer:

Project Data:

Completion Date:     7/16/2020

Square Footage:      79200

Building Use:           Speculative Core and Shell Office

Project Description:

Mass timber has a strong potential to be a sustainable solution for future office developments. Besides being low carbon, these environments improve health, well being, productivity, and air quality in offices where employee health is an increasing concern.

The project re-imagines commercial office spaces into mass timber. It is a prototype that can be built today within code confinements, industry standards, client expectations and economy while peering into the future.

An existing office property in Irvine is converted to mass timber structure, utilizing best approaches to the material in construction, structural efficiency, architectural and planning concerns. This office building was a 3-story, 79,200 square foot building, with 15’ floor to floor, a steel structure with concrete filled deck and steel moment frames on a 30’ x 30’ grid.

The redesign aimed to expose as much timber as possible, maintain a five-foot planning module for multi-tenants, and keep the same building height. Best practices for commercial office development standards were used for the mechanical systems and structural framing. The building changed to a Type 3-B construction; maintaining the size, height the desire to expose the timber structural frame.

Several structural depth studies were conducted to evaluate the reasonable spans for CLT panels at differing thicknesses and reasonable floor heights. The framing maintains an open floor plan with cost effective floor height. As the intent was to be code compliant, the approach to have the lateral systems from steel was maintained. However, to maintain the benefits of mass timber, a CLT diaphragm was utilized in lieu of a concrete filled metal deck diaphragm.

To accommodate for the mechanical system, a smaller structural bay allowed larger ducts to travel through the building and the smaller ducts to distribute between the larger girders. This allowed large girders and mechanical system to occupy the same plenum space. The VAV mechanical system is left exposed.

The structure is coordinated with the interiors to create a flexible plan. The 20x25 grid optimizes the structural depth and the mechanical distribution. The five foot planning module with a 20’ CLT span is supported by a fully exposed 7 ply CLT floor slab. The floor assembly is has increased acoustical performance due to its mass and acoustical layering. The deeper girders can create planning divisions natural demising lines within the plan. Exposed wood columns become an architectural element.

The optimized grid spacing with maximized panel spans decreases cost. The premium cost for CLT is neutralized by the expedited construction. In an office development, per unit costs will decrease due to the volume of wood purchased and future increases in market demand. Exposed timber aesthetic saves costs of finishes and labor ($5-10/SF).

A life cycle analysis is conducted on the baseline and redesign. The results showed CO2 emissions decrease from 2.4 to 1.4 million kg of CO2, accounting for 40% decrease in embodied carbon. These savings, when multiplied to an entire development, will exponentially increase. Increased understanding of mass timber construction in Southern California can help mass timber buildings commercialize rapidly.