Construction works on skyscraper hit the historic Hudson's building foundation

Construction works in a skyscraper have hit the foundation of the historic J.L. Hudson's department store.

Hudson's was a retail department store located in Woodward Avenue, Detroit, Michigan. It was considered the second tallest department store worldwide back in 1961. However, business declined by the middle 1970s and the store was forced to close in 1983. The building was demolished in 1998.

The foundation of the new $909 million skyscraper will consist of caissons. The foundation will support the 278-meter building that will be used for multiple purposes.

Due to the incident, drilling will be delayed but officials state that there are no concerns about the time-frame of the construction. "Hitting obstructions is a very normal part of drilling caissons," Joe Guziewicz, vice president of construction for Bedrock LLC, Dan Gilbert's real estate development company, said. The delays are assumed to be about 300 hours so far but the company states that it's part of the so-called obstruction time that is common in all large infrastructure projects. However, Mr. Guziewicz refused to reveal how many obstruction hours have been considered in the design to avoid delays.

The foundation works require more than 150 caisson holes, that will reach a depth of 36,5-42,5 meters below street level, to be drilled in the surface of the ground. The holes' diameter ranges from 1,5 to 2,13 meters. Until now, 74 of them are drilled and the rest will be completed by the end of August, 2019. "Complex foundation work has been in progress and will continue. The structure will begin rising above grade once the complicated foundation work is completed," Bill Emerson, CEO of Bedrock, stated.

The new skyscraper will occupy an area of more than 93,000 m². Its height will be more than twice the 25-story Hudson's building.