New London — The National Coast Guard Museum Association has hired two Connecticut firms to assist in the ongoing pre-construction work on the estimated $100 million museum planned for the downtown New London waterfront.

The museum association has selected North Stonington-based construction company A/Z Corporation as the pre-construction manager, and GEI Consultants, with offices in Glastonbury, to provide geotechnical services.

"Hiring these two experienced construction firms is an important step forward for the future National Coast Guard Museum and the public access project," Richard J. Grahn, president of the museum association, said in a prepared statement.

A/Z Corporation, working with the museum architects and engineers, will review the schematic design and help develop an updated cost estimate and construction schedule, as well as recommend construction methods and materials.

The museum association did not disclose how much it is paying A/Z Corporation or GEI Consultants. The museum association's most recent tax filing shows that in 2016, it had $2,813,574 in revenue and $1,066,984 in expenses. In 2015, expected revenue was $3,698,678, and there were $858,114 in expenses.

The museum association now has six full-time staffers and one part-time. It outgrew its old office at the back of 239 Bank St. and began renting office space adjacent to Crocker's Boatyard on May 1.

Salary made up $276,976 of its expenses in 2015, and $501,519 in 2016.

"With a recent anonymous gift of $1 million, we have cash flow to take us through the detailed design and engineering workup to make us shovel ready which is estimated to be completed in the second half of next year," Drew Forster, director of communications and public relations for the museum association, said by email. "We have brought in a more robust development team to continue to raise the necessary funds in order to meet the future planning, design and construction milestones."

Site testing done by GEI Consultants will start the week of July 16 at the museum site and the planned location of the pedestrian bridge from Water Street to the river side of the railroad tracks adjacent to Union Station. GEI will have a barge adjacent to the museum site as part of the testing.

After approximately a month of activity, the site will be quiet again as the impact of the test results is analyzed, and the museum design is refined based on those results, Grahn said.

The museum is being designed for pre-K through adult audiences with a Science Technology Engineering and Math, or STEM, Discovery Center, multiple exhibit floors and gathering spaces. So far, $36.1 million has been raised. That includes $5 million in federal funding and $20 million from the state.

j.bergman@theday.com