Demolishing a structure without disturbing the public at large can be a challenge on some jobs. When the job at hand is a stretch of California highway bridge, the need for organization, on-site management and timeliness needed to prevent disruption is increased exponentially.
That was the challenge presented to Mountain View, California-based Ferma Corp. when they were awarded the contract by Livermore, California-based RGW Construction Inc. in February 2017 to take down a stretch of highway bridge between Interstate 880 (I-880) at the existing overcrossings of 23rd and 29th Avenues in Oakland, California. RGW was contracted directly by the California Department of Transportation (Caltrans). This demolition was scheduled from July 7 to Sept. 29, 2017, to make way for operational and safety improvements, with a second stretch of bridge slated to be demolished starting in October 2018.
On the clock
Ferma Corp., which is a full-service general engineering firm that concentrates on demolition, site preparation, excavation, grading, recycling, shoreline restoration and protection, paving, hazardous waste remediation and landfill construction and closure, was founded by four brothers and a partner in 1963 as a site-clearing business. Three generations later, Ferma Corp. specializes in large fast-track demolition projects of buildings and structures constructed of heavy steel and concrete. Their sub-niche is performing this style of demolition on structures of significant height, which made them perfect candidates for the Caltrans bridge demolition.
According to Marc Ferrari, president of Ferma Corp., once the company was awarded the job, it went to work immediately collaborating with Caltrans to plan the demolition in the most effective way.
“We worked with a structural engineer during the implementation stage to not only accommodate previous commitments by past involved contractors, but to include Ferma's resources in the design of the bridge removal,” Ferrari says of the Caltrans collaboration. “This was a challenge as the owner had previous demolition plan submittals, and Ferma had to convince Caltrans there was a better and safer way. Working with the structural engineer, Ferma submitted several updated demolition plans and drawings to make the general contractor and Caltrans comfortable with past commitments while implementing methods and means that Ferma was comfortable with.”
To prepare the bridges for the demolition, Ferrari says Ferma created a “by the minute” construction schedule to ensure it'd be in compliance with the strict lane closure restrictions. The company sourced backup equipment for redundancy in case of breakdowns, brought an extra trench plate on-site for freeway protection and designed special debris trailers to be placed under the spans to catch the concrete rubble to expedite the cleanup at the end of each shift.
“Once an approved demolition plan was accepted by the owner’s team, the general contractor placed the traffic controls and lane re-configurations, and we were on the clock,” Ferrari says.
Over a span of 10 night shifts and 20 day shifts, Ferma Corp. was tasked with removing the existing bridge to make way for a new over-crossing bridge.
Because of the tight time frames, expediency was the key to staying on schedule. According to Ferrari, this was exacerbated by the threat of a $25,000-per-hour penalty levied by Caltrans for missing a lane opening.
“Ferma had 10 night closures with a four- to five-hour window to remove approximately 300 linear feet of bridge, including six 70,000 to 90,000 pound steel girders, concrete deck and bents over I-880. We also had to remove another 350 linear feet of bridge on each side of the freeway during the day shift,” Ferrari says. “The night closure included the time for the general contractor to close the freeway as well as time for Ferma to place protection on the 880 freeway to protect the roadway and cleanup time.
“We placed shoring towers under the girders and torch-cut the girders in half during the closure so our 90-ton rough terrain crane could pick each girder in two pieces. The reason for this was the closure hours were so tight that there was no time to set up a conventional crane. To perform four picks per shift in the four- to five-hour closure time was impressive.”
The tools of the trade
To conduct the tear down, Ferma used multiple 100,000-pound excavators to remove the 25-foot-wide deck along with the cantilevered sidewalk on each side of the bridge. Since the bridge was located close to residential neighborhoods, the excavators were equipped with crunchers and shears to eliminate the noise of using a breaker. The deck was removed to expose the girders so Ferma could prepare them for the next closure’s crane pick.
“In essence, Ferma had two to three working hours each night shift to accomplish the removal of 8,750 square feet of concrete deck with two layers of rebar,” Ferrari says.
Thanks to the company’s emphasis on comprehensive planning and adherence to its deadlines, Ferma Corp. was able to complete the scope of work in the amount of closures specified. And despite its expedited schedule, recycling was at the forefront of the project, according to Ferrari.
“One-hundred percent of the steel and concrete removed from the site was recycled, and all the material brought in for protection was removed and will be reused on other projects,” Ferrari says.
All the concrete from the project was sent one mile down the road for recycling, which minimized the trucking needed for transport. All of the steel derived from the project was sized so that the maximum amount could fit into the trucks for transport, which further reduced the company’s hauling footprint.
Beyond recycling, Ferrari says that Ferma Corp. took a green approach to selecting the equipment to be used in the project.
“All equipment used was Tier 4 equipment, which greatly reduced toxic emissions during the demolition,” Ferrari says. “Dust was suppressed using updated attachments, thus minimizing the use of water as dust control.”
Ferrari credits the expediency and seamlessness of the project, in part, to the company’s insistence on investing in the right equipment for the job.
“Owning the largest hydraulic shears, hammers and processors the country has to offer mounted to the nation’s largest fleet of heavy high-reach excavators allows Ferma to demolish high-rise structures at a pace that exceeds what most in our industry achieve in a low-rise environment,” Ferrari says.
Beyond the equipment, Ferrari says that working with a team capable of adapting to challenging conditions on the fly was the differentiator that helped make the Caltrans bridge demolition a success.
“The takeaway is that many jobs are similar, but each requires unique engineering and planning,” Ferrari says. “The work environment is changing with new rules and regulations constantly being amended or added. These changes require our team to be fully aware of current regulations in order to stay in compliance.”
Ferma Corp.’s commitment to going above and beyond on the Caltrans bridge demolition did not go unrecognized. Thanks to their emphasis on recycling and reducing the environmental impact of the job, Ferma Corp. was recognized by the National Demolition Association (NDA), Washington, which awarded the demolition contractor with the 2018 Excellence in Demolition award in the $500,001 to $2,000,000 category Feb. 24 at the NDA's Demolition Austin event.
The Excellence in Demolition award honors NDA members who have demonstrated significant environmental conservation and community involvement and is presented annually to companies that have made a significant "quality of life" impact on their community, according to the DNA.
“Winning the 2018 Excellence in Demolition award means a great deal to Ferma,” Ferrari says. “It’s not just an award; it means that our peers have acknowledged our efforts and achievements in evolving our trade."
While the award was great to receive, Ferrari says, the symbolism of what it embodied was even more important for the his team.
“It represents growth and opportunity for success as a team,” he says. “It takes courage to start every project and determination to complete the job and make our mark. The opportunities are out there for us to be successful as long as we stay true to who we are as a company—honest, hardworking individuals who are committed to working safely so that all of our coworkers return to their families at the end of their shift at least as good as they arrived to work that day.”