From Tech Transfer Newsletter, Fall 2006 » printer-friendly

The Balsi Beam: Protecting Workers with a "Shield of Steel"

By Alyssa Sherman, Technology Transfer Program

Since 1924, 166 Caltrans workers have been killed in work zones. To protect construction and maintenance field crews from injury or death, engineers at the California Department of Transportation (Caltrans) Division of Equipment designed and built a unique mobile work zone barrier called the Balsi Beam. The Beam serves as an extendable physical barrier that deflects traffic away from maintenance workers by forming what Caltrans calls a "shield of steel."

The Mechanics of the Beam

Named for Mark Balsi, a Caltrans worker injured in a work zone crash in 2001, the Balsi Beam is a modified semi-trailer that is transported by a tractor cab. With its own dedicated cab, the Beam can easily be transported to a worksite at normal highway speeds without the need for any permits.

Set-up and break-down each take approximately five minutes and involve a simple process. Using hydraulic power, the Balsi Beam's two beams are rotated and then telescoped to provide 30 feet of continuous protected workspace. The Beam can be rotated to the left or right, depending on which side of the road a protective barrier is needed.

While crash attenuating trucks at each end of a work zone protect workers against the possibility of head-on collision, the Balsi Beam can deflect an errant vehicle that strays into a work zone from an adjacent lane.

Where the Beam is Used

The Beam was researched and developed by the Caltrans Division of Research and Innovation and the Division of Maintenance in response to Balsi's accident. Prior to the creation of the Balsi Beam, no known safety device used the "shield of steel" concept to protect workers.

The Beam is considered a highly portable positive protection technology, which means that it contains and redirects errant vehicles from intruding into a workspace. Traditionally, positive protection has been achieved through complete diversion of traffic to another roadway or use of a portable concrete barrier. By cost-effectively and quickly providing protection, the highly-portable Balsi Beam increases safety in work areas where a concrete barrier is not feasible.

The Beam is designed to be used in median or shoulder areas to protect highway workers against accidents. Crews can use the device in various work zones, including for irrigation repair, bridge repair and inspections, and median repair. Other areas where the Beam could work include litter pickup, pavement core sampling, pothole patching, signal or lighting installation and maintenance, culvert repairs, and edge/guardrail repair. The Beam is considered an ideal safety device for bridge maintenance work, which requires workers to work in small spaces between moving traffic and a bridge rail.

The Beam was recently used by Caltrans District 3 for work on Interstate 80 Eastbound, between Truckee and the Nevada border.

Praise for the Beam

Reviews of the Beam from transportation departments in other states have been overwhelmingly positive. Comments include praise for the device's user-friendly interface, ease of operation, and potential to save lives.

Recently, the Beam won the 2006 Caltrans Excellence in Transportation Award for Maintenance, Operations, or Equipment. The annual competition recognizes excellence in transportation design, construction, traffic operations, maintenance, planning and improvements throughout California. Nominations come from Caltrans districts, corporate programs, local agencies and others. They are judged by a panel of experts not employed at Caltrans.

Purchasing a Beam

Caltrans currently owns and maintains the only Balsi Beam. However, after gathering enough feedback to determine where and how the Beam can be used most effectively, Caltrans and FHWA plan to collaborate with other state agencies and utility companies to design and implement similar work zone protection devices. Caltrans is currently working with the Minnesota and New Jersey Departments of Transportation to license and replicate the Beam for their use.

The prototype cost approximately $217,000 to build, but Caltrans expects that cost to drop significantly once other models are produced. Caltrans anticipates that interested cities and counties will be able to sign licensing agreements with Caltrans to build their own beams.

Caltrans holds a patent on the device. State highway agencies, counties, or cities can obtain more information and plans for constructing the device by contacting Juan Araya in the Caltrans Division of Research and Innovation. He can be reached at (916) 654-8170 or via e-mail at juan_araya@dot.ca.gov.

Portions of this article are reprinted, with permission, from the August 2004 issue of FHWA's Transporter.

© 2008 Regents of the University of California