The small industrial buildings and blighted homes that once dotted the landscape of Detroit's Delray neighborhood are gone for good as demolition and site-cleaning work for the Gordie Howe International Bridge is in full swing this summer.

The long-anticipated bridge construction project is starting to take shape on the Michigan side of the Detroit River, as cranes have been working along the riverfront in recent weeks.

The cranes were drilling test shafts into the ground that will determine the final design of the new span and its towers rivaling Detroit's 73-story Renaissance Center, said Aaron Epstein, CEO of Bridging North America, the consortium of international infrastructure companies that is building the bridge.

Excavators are tearing up what's left of concrete foundations from one-time businesses in Delray that were uprooted through condemnation proceedings to acquire the 167 acres needed for the U.S. Port of Entry customs of plaza that will connect the new bridge to I-75. Some 255 buildings have been demolished in Detroit to make way for the new international crossing.

Crane operators and construction companies are currently working to shore up the seawall along the Detroit River between Lafarge North America's riverfront aggregates plant and McCoig Concrete's plant where the new bridge will make landfall on the Michigan side.

On Springwells Court, an acre lot of modular office trailers totaling 28,000-square-feet has been installed to house the dozens of field engineers and support staff who will work on the construction project over the course of the next five years, Epstein said.

About 40 Michigan-based companies are under contract on the bridge project working everything from earth-moving and fence installation to supplying tools, portable toilets and project vehicles, according to Bridging North America.

"We're looking at over the course of the next month or so having another 10-15 contracts we're going to put out on the street for bids. ... A lot of dirt work contracts for the earth work that has to go on," Epstein said.

The consortium of companies declined to release names of sub-contractors. But in recent weeks, Detroit-based demolition firm Homrich has had crews on site tearing out concrete foundations inside the footprint of the customs plaza.

Brian McKinney, co-owner Detroit-based Gayanga Co., a minority-owned construction and demolition company, previously told Crain's his company has won a subcontract for site work for the bridge project, but could not comment on the nature of the work.

The new six-lane, cable-stayed bridge, customs plazas and highway connections are expected to cost $2.9 billion to construct, with an additional $1.5 billion in operating costs over 30 years through the contract Bridging North America inked with the Windsor-Detroit Bridge Authority last fall. The consortium of companies leading the Bridging North America partnership includes ACS Infrastructure Canada Inc., Fluor Canada Ltd. and Dragados Canada Inc.

In the coming weeks, Bridging North America will be putting out for bid contracts for construction work on and around I-75 where the interstate highway will be eventually connected to the customs plaza and Gordie Howe bridge, which is being financed by Canada.

Those projects includes demolition and concrete work, traffic signs and management, surveying, temporary barriers and concrete pavement pumping stations, Epstein said.

"There's just a lot of different skill sets required that we're looking to obviously put qualified subcontractors on," he said.

General contractors have not expressed any issue with finding labor for subcontract work, according to Epstein.

"That is always a concern, but we haven't seen that addressed to us at this point in time," he said. "And we don't foresee that with the upcoming work in this construction season."