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comment HMH, HOK Go for LEED-Gold
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The recently completed $270 million California State Teachers’ Retirement System headquarters in West Sacramento is going for LEED gold certification.
This 13-story structural steel office tower, constructed over a five-level parking structure, is located on the banks of the Sacramento River.
The general contractor on the project was Harbison-Mahony-Higgins Builders, the architect was HOK, project developer was Panattoni Development Company and the project oversight manager was Principal Global Investors.
Work on this 6.85 acre site included a deep pile foundation and a five-level parking structure that houses 1,200 parking stalls.
The 289-ft tall tower also includes a full-service cafeteria, 1,250 work stations, formal boardroom and financial trading center.
CalSTRS says it adopted a team-build approach to building construction: all development and construction team members began and finished the project together. This approach reduced planning time, development and construction costs.
The result was a net $13.2 million savings in construction costs.
The green design features improve CalSTRS operational efficiencies and save money, including an estimated $130,000 annually in electricity costs.
Building systems were designed to require 20% less energy and 30% less water than a comparable traditional structure. Architecturally, the building is set apart by its 43-ft-high, 8,000-sq-ft entrance lobby. A specialized window system allows for maximum daylight and views for 90% of the occupied space.
Other green elements include:- Landscaping with native, water-conserving plants.
- Building materials made of 10% recycled content.
- Fritted exterior lobby glass to diffuse sunlight.
- Concrete base flooring made with recycled rocks, marble and glass.
- Overall water usage reduced by nearly 40% with high-efficiency irrigation and low-flow fixtures.
- Reduces greenhouse gas emissions, promotes local manufacturing by using at least 20% of construction materials from within 500 mi of project.
- Reduces waste, resource use, saves landfill space by recycling about 75% of construction debris.
- Reduces risk of ozone destruction by using CFC-free cooling, refrigeration and fire protection systems.
- Minimizes building heat generation by using reflective roof and sidewalk pavers, covered parking and shade-producing landscape.
- Use of “fritted” glass diffuses sunlight and minimizes the lobby’s solar heat.
- Individual floor-mounted air flow control to most of the workstations.
Paul Woolford, director of design for HOK, says the firm wanted to create both a “signature statement” for CalSTRS that both salutes the history of the Sacramento riverfront and boasts architectural innovations in energy efficiency.
“Internally, we’re using an under-floor air system, in which air is distributed from beneath the floor up into the work area, and pulled out through the ceiling,” Woolford says. “This is the reverse of traditional buildings, which pushes air down.”
Woolford says the purpose of the under-floor system is partly to reduce energy costs, but primarily to create “a far better place to work in terms of indoor air quality.”
“There’s constant replenishing of air in the workspace,” he says. “At your desk, you can actually monitor the speed, direction and amount of airflow. You have more control over your indoor environment.”
“CalSTRS was willing to think long-term with its headquarters,” Woolford says. “Imagine if you’re saving a third of your energy costs starting in year one.”
Woolford says HOK researched the history of the project’s location at the confluence of the Sacramento and American rivers and found that it was a former shipping site. This knowledge also helped drive the building’s unique shape.
“The design is emblematic of a giant, billowing glass sail,” he says. “There’s a gentle curve and arc in the profiles. It’s paying tribute to the site and heritage of the community in which it’s built.
“We actually rotated the building off the traditional street grid so that it’s on a true north/south orientation. By doing that, we carved out a triangular corner of the site, which we’ve turned it into a public-access garden that connects up to the river walk.”
Tim Spence, senior project manager for general contractor Harbison-Mahony-Higgins Builders of Sacramento, says building with energy efficiency in mind is rapidly becoming the normal course of business.
“Harbison-Mahony-Higgins and (parent company) Swinerton have been, over the past couple of years, promoting a big push for staff to become LEED accredited professionals,” Spence adds. “As we do that, we understand the processes we have to undergo on the job site. Building green is no longer seen as a challenge, but simply an additional task that we have.
“It puts a little more on our plate, but we’re finding that it’s actually cool to be green.” The project team included Airco Mechanical (HVAC/plumbing), Schetter Electric Inc., Concrete Services and Gayle Manufacturing Co. (structural steel).
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