Midwest Wrecking Co.'s demolition of a Dallas County government building at Stemmons Freeway near Motor Street gave motorists quite a show this past spring.
Dallas County chose Midwest Wrecking to demolish their 15-story building northwest of downtown Dallas, where in its place, Dallas County will build a new campus-style Institute of Forensic Science.
Midwest began this past January gutting the interior of the building, removing about 1,700 tons of material. They brought Wildcat Rentals on in March as a subcontractor with their ball and crane demolition equipment to knock down the steel-reinforced, poured-in-place high rise.
Although the structure might have made a good subject for implosion, there were several factors that resulted in Midwest and Dallas County choosing traditional ball and crane demolition. The extensive glazing work of the adjacent County's Health and Human Services Building was a concern but not the primary reason for the decision. It boiled down to dust and dollars.
Brian Choate of Midwest Wrecking said, "Traditional ball and crane demolition causes small amounts of dust but over a longer period of time. Even though the dust cloud of an implosion lasts for only a matter of seconds or minutes, the potential impact to Stemmons Freeway could last much longer."
If the wind were to be blowing from the south, the resulting dust cloud and debris drifting onto Stemmons Freeway, only a matter of yards away, would create the need to close the 10-lane freeway and service roads for perhaps over an hour or more for cleanup. The high cost of interstate lane closures for that length of time was a cost that neither the county nor the contractor wished to chance, according to Jeremy Anderson, superintendent for Midwest Wrecking.
Dan Savage, assistant Dallas County administrator, said, "Midwest's bid with traditional demolition was substantially lower by hundreds of thousands of dollars. We saw no merit in spending extra money imploding."
Wildcat Rentals Inc. of Fort Worth joined the effort the second week of March. Their Link-Belt crane has a 220-foot boom and is equipped with a 8,000-pound ball. The Lorain has a 190-foot main boom swinging a 10,000-pound ball.
The center core of the building that supports the penthouse was the final portion that Wildcat brought down, according to Kevin Maddox with Wildcat. This allowed Midwest time to reinforce an underground electric transformer room between the front of the building and the service road. Before allowing the heavier penthouse room to fall, Western Wrecking brought in a number of steel shoring panels from United Rentals to cover that area to prevent damage to the transformer.
"Wildcat will demolish the concrete and steel to the structure's second level, where we can complete the demolition with excavators, loaders and backhoes," said Anderson. To complete the demolition, Midwest Wrecking "will separate the steel from the concrete rubble and process as much of the concrete as possible with their excavator-mounted processor." The steel and concrete will be hauled to local recycling facilities. Choate calculated the amount of recyclable concrete at about 15,000 tons and steel at about 1,500 tons.
Bill Stimson, AIA, of HKS Architects of Dallas served as the lead architect and Johnny Luttrell, AIA , also of HKS served as project manager for the design the new 111,000-square-foot Institute of Forensic Science for Dallas County. The campus will consist of a four-story forensics laboratory, a two-story administration area and a one-story medical examiner's office.
McCarthy Builders recently won the bid award and will begin construction this summer. Completion is expected in the spring of 2008.