Piecing together history

Beginning in the early 1800s, the commonwealth of Massachusetts began constructing a statewide system of cutting-edge (for the time) insane asylums. Construction on the Worcester Insane Asylum began in 1832, with the grand opening in 1833. The centerpiece of the new hospital was an elaborate administration building topped with a 135-foot-tall clock tower built in 1877.

The Victorian-era facility in Worcester was officially closed in the early 1990s with several phases of demolition taking place over the years. The administration building with its famous clock tower was one of the last remaining features of the original complex and was scheduled to be preserved. Unfortunately, a fire in 1991 caused significant damage to the interior structure and rendered the building inaccessible. The desire to preserve the structure was balanced against the need to prevent a dangerous collapse, and a decision was made to deconstruct and relocate the clock tower on-site as part of the new $300 million, 300 bed Worcester Recovery Center & Hospital as a tribute to the historical past.

The Massachusetts Department of Capital Asset Management and Maintenance (DCAMM) hired Gilbane, based in Providence, Rhode Island, as a general contractor and construction manager to oversee this work. Together with DCAMM and Gilbane, Costello Dismantling of West Wareham, Massachusetts, created a work plan to address the challenging scope of work and the sensitivity needed to work adjacent to an occupied hospital. The team employed more than 20 subcontractors including engineers, health and safety professionals, masonry restoration experts, clock repair specialists and environmental remediators.
 

A painstaking process

The deconstruction was a painstaking process that involved removal of each stone by hand, numbering, photographing and cataloging them so the tower could be re-erected properly. The entirety of the top 65 feet of the tower was saved in this way, along with a significant portion of the remainder of the building. The deconstruction and demolition team consisted of a crew of 17 masons, 13 environmental professionals, 15 demolition specialists, two engineers and four full-time safety officers working together to create a successful project.

One of the most difficult challenges involved the extreme height that crews needed to work at to recover the tallest portions of the tower. The City of Worcester Fire Department would be able to perform aerial rescues at heights up to 70 feet. This project involved months of work at heights up to 135 feet, using 150-foot boom lifts and man-baskets suspended from cranes. A mechanical failure at height could leave workers stranded with no outside rescue available.

To safeguard against this, the team always had at least two lifts on site capable of performing a rescue at any height and a specifically trained aerial rescue team comprised of key site personnel with defined roles and responsibilities in the event of a rescue. The team had to make use of this special training once when workers encountered a mechanical failure at height in one of the lifts. Over the duration of the project there were zero loss-time accidents.

A falling debris engineering study was referred to which located the potential fall zone of debris from the building within a radius of 40 percent of the building height. This raised concerns as to the proximity of the newly occupied hospital which, in places, closely challenged this fall zone. Intrusion into the hospital space was an absolute prohibition to the basic tenets of the work plan. Several critical factors came into play, therefore, when executing a demolition plan. It became apparent that the slate shingle roofing could become loosened and airborne during roof demolition and could potentially sail out of the exclusion zone. The team designed a mesh wrapping system around the eaves of the clock tower which would capture any fugitive slates and contain them safely.

Similarly, once the tower portion of the building had been removed manually, the body of the building remained for dismantling with significant portions of the field and decorative sills, lintels and quoins needing to be saved. As previously mentioned, a significant fire in 1991 had rendered the interior of the building structurally deficient, inaccessible and asbestos contaminated.

All work activities were performed from the perimeter. The team utilized two Volvo high-reach excavators as the primary demolition machines. A Volvo EC700 with 105 feet of boom and a Volvo EC460 with 85 feet of boom were both equipped with rotating grapples to carefully dismantle wall sections and place individual stones in designated areas for decontamination and recovery. The precision material handling control was absolutely essential to maintaining the tight working envelope.

The reconstruction of the lower 65 feet of the new clock tower monument required 8-inch-thick ashlar granite stones to achieve finished exterior elevation. Although some of the salvaged stones were within this tolerance, workers discovered that the lower on the building face they went, the thicker the stones were.

Crews regularly encountered stones more than 12 inches thick. Rather than sort through thousands of stones to find 8-inch-minus thickness, they collected the 4,000 square feet required for the new construction (nearly 4,000 stones) and sent them to a local stone fabrication shop to have them sawcut to the required thickness, palletized, and sent back for the new project. The time savings achieved by opting for this solution easily outweighed the expense of sorting.
 

A collaborative effort

This project was truly a collaborative effort, with Gilbane and DCAMM working tirelessly to manage the safety and efficiency of the expansive construction and demolition site. Four full-time safety professionals from the prime contractors and subcontractors worked together to create a healthy and functional job site. While demolition was ongoing, construction was completed on the brand new hospital adjacent with demolition temporarily paused for the grand opening. After the opening of the new hospital, the task became ever more strenuous, with all three parties (DCAMM, Gilbane and Costello) working together to protect the safety and privacy of patients as the adjacent building became occupied.

Demolition was completed in March 2013. More than 13,000 man hours were logged on just the tower deconstruction, remediation and dismantlement, with zero loss-time accidents. Costello Dismantling, Gilbane and DCAMM worked collaboratively to craft and execute a successful deconstruction and demolition plan. The clock tower monument is in the process of being reconstructed, with all of the raw materials harvested from the original structure catalogued and numbered, capping off the new hospital with a terrific tribute to the past.

The article was submitted by Costello Dismantling, based in West Wareham, Massachusetts.