Project Profile: Domino Sugar

At first glance, it may simply look like four cylinders on a concrete pad. But constructing the new silos at Domino Sugar involved extremely specialized industrial equipment, customized installation tools, intense vertical construction at the water’s edge, and the critical precautions needed to build a Class 2 Explosive Environment.

The goal of the three-year construction project was to significantly expand Domino’s finished-sugar storage capacity at its Baltimore processing plant. To achieve that, the project team would have to erect four new, 160-foot-tall, 32-foot-diameter silos (capable of holding 14 million pounds of sugar) plus a 180-foot-tall stair tower to access the silos, a 180-foot-high conveyor and pedestrian bridge connecting the processing plant to the silos, and multiple pedestrian bridges between silos.

The project would include making structural improvements to Domino’s 12-story processing plant (portions of which are over 100 years old) and engineering the silos to also provide structural support.

TranSystems (formerly WBCM) was hired to complete the design of the project while WBCM Construction Services provided preconstruction support and served as construction manager at risk. A specializing silo construction company, Tank Construction, was engaged to assist with the design and erection of the silos.

“These were the combined tallest and heaviest silos Tank Construction had done to date so they had to re-engineer their standard jacking system” for erecting silos, said Mike Baker, President of WBCM Construction Services.

All the subcontractors had to cope with “a site that is basically a postage stamp right on the waterfront and a plan to put a whole lot of very high, vertical structures on it,” said Jesse Lindsay, Executive Vice President of TranSystems.

“One of the biggest challenges was the silos have insulation on the outside of them, but you can’t install the insulation until the silos are built,” Baker said. “Typically, you would use manlifts but half of the silos face the water and there was no room for a manlift.”

Consequently, the insulation was installed with a crane and a crew working from swing stages hanging off the tops of the silos.

Alliance Exterior Construction – which was contracted to install fire-rated wall and roof panels on the stair tower and bridges as well as EPDM roofing, aluminum windows and metal doors – faced an equally daunting challenge.

Because sugar dust can be explosive and the processing facility is rated as a Class 2 Explosive Environment, the exterior panels were highly specialized.

“They are heavy, fire-resistant panels that are stuffed with mineral wool,” said Matthew Clark, Project Manager for Alliance Exterior.

Measuring 42 inches wide, 20-plus feet tall and six inches thick, the panels weighed hundreds of pounds apiece.

“They were very difficult to handle and, because of their fire-rated nature, we couldn’t use traditional insulated panel manipulation equipment which relies on vacuum cups, much like our large glazing installations,” Clark said. “Instead, we had to design a custom steel plate that was mechanically anchored through the panel at its head so that it could be hoisted into place without affecting the structural integrity of the panel.”

Although the Alliance Exterior crew found ways to use hoists to raise panels as high as 180 feet, “you still needed to have people up in the air to install the panels once they reached their destination,” Clark said. “We could not set up manlifts. In some places, we could use a traditional swing stage setup. But in other places, like the bridges connecting the silos, there was no space to set up a swing stage, so we had to send guys up as high as 180 feet in bosun’s chairs.”

Due to fire hazards, crews working onsite had to abide by “a near-zero tolerance rule for spark-producing equipment,” Baker said.

Consequently, workers made heavy use of hand tools, carefully planned and got permits for hot work, and conducted a large amount of work on nights and weekends when the refinery had planned a shutdown.

Contractors vetted every item used in construction, right down to screws and bolts, to meet the exacting requirements of the industrial facility.

Due to the necessary sequence of work, crews also contended with a period of intense activity.

On the three-year project, “we knew from day one that approximately 40 percent of the work would have to be completed in the last 20 percent of the schedule,” Baker said.
Heightened quality control work was essential to the successful completion of such a specialized project.

“We were tenacious,” said Clark, who did intensive reviews of every spec, drawing and submittal. “When it came to drafting the project, I revised the shop drawings five times to make sure they reflected every condition exactly. I think the quality of the shop drawings greatly improved our ability to execute the job properly.”

According to Clark, Baker and Lindsay, the ingenuity of the field team was vital to devising vertical access systems, contending with unexpected discoveries (such as the huge concrete vault found beneath the site), and delivering an extraordinarily demanding and unusual project.

Clark also credits Alliance CAD Specialist Sam Harris and his use of their geospatial laser scanner to the project’s success.

“You know the old adage of measure twice, cut once? Well, the laser scans allowed us to pull millions of datums across the steel structure and ensure that every panel fit the first time,” Harris said.