Name: Tom Burkhart
Title: Senior Project Manager
Company: GHD
Professional Designations: P.E., Model Law Structural Engineer, Post Disaster Safety Evaluator
Q: What is your field of focus and what particular products do you specialize in?
I am a structural engineer engaged in detailed design and multidiscipline project management. I have designed dozens of on-site precast building projects. Since the 1990s, I have also designed various hydroelectric conveyance and control projects under Federal Energy Regulatory Commission jurisdiction, including utility and bridge projects using off-site precast concrete components.
Our office specializes in construction projects at remote sites. We determine how to construct facilities during short construction windows in late fall and early winter at altitudes of up to 13,000 feet above sea level. In some cases, our designs involve using helicopters to deliver construction materials and equipment.
I have extensive design and construction experience in all modern construction materials, but my more recent focus has been on projects constructed of concrete and steel.
Q: What are the benefits of using precast concrete products?
We have found precast concrete affords several advantages over cast-in-place concrete or other building materials when working around streams with the U.S. Army Corps of Engineers, the U.S. Forest Service and the U.S. Fish and Wildlife Service.
Photo courtesy of GHD.
We’ve designed bridges using precast concrete elements which were dropped in place on supporting abutments while avoiding stream bed disturbance. Precast concrete construction provides significant additional benefits on mountain agency water conveyance projects where utilities providing water for consumption or revenue through hydroelectric generation have short outage periods in the late fall and early winter. We have also perfected water conveyance system replacement by using precast. In the past, this process relied on wood flume construction. Precast concrete has proven to be more durable than wood, and is resistant to forest fires, landslides and rockfall. Consequentially, it’s more economical over the long term.
Precast construction also offers the opportunity for significantly increased quality control on critical infrastructure projects. By precasting flume sections, construction can begin sooner and precast sections can be staged for the start of the facility’s outage. Where possible, precast sections are placed on cast-in-place foundations on top of an engineered earth “bench” or on an elevated steel structure by conventional construction equipment. However, because many sites are not accessible by conventional equipment, we engineer the sections and handling methods using high-strength, lightweight concrete so that they can be lifted and placed by helicopter.
Q: What are some unique or interesting projects on which you specified precast concrete?
In California, designing dependable water conveyance systems is very rewarding. For example, El Dorado County is dependent on a conveyance that originated shortly after the gold rush era. The county receives about 1/3 of its drinking water from this system. To have an opportunity to engineer a long-lasting, durable replacement for the aged and antiquated systems of the past is incredibly satisfying. In collaboration with clients, our structural, geotechnical, civil and land survey experts provide communities with best-value solutions.
Some of the hydroelectric conveyance projects Burkhart works on involve the use of helicopters for delivering precast concrete products. Photo courtesy of GHD.
Q: How have you seen precast concrete evolve? How do you see it continuing to impact your work?
Over the course of my career, I have seen precast concrete evolve in various ways, including its use in building façades and structural systems, MSE wall veneers, bridges, and, of course, water conveyance and drainage structures. When I began my career, I had no idea that I would be designing projects using precast elements. Today, I definitely see the benefits of precast concrete in construction, including scheduling and cost benefits, the ability to meet compressed construction schedules and the improved quality control inherent to construction in a controlled environment.
For more information on GHD, visit ghd.com.
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