An excavation company involved with major developments like Somerville’s Assembly Row and Worcester’s Polar Park has opened a new corporate office and maintenance facility in Billerica.

W.L. French Excavating Corp. is occupying the new, two-building, 66,000-square-foot complex on a 22-acre property at 14 Sterling Road.

The 48,000-square-foot maintenance facility includes 10 drive-through maintenance bays, three high equipment bays with 5-ton and 10-ton overhead cranes, truck tire carousel, diesel filter cleaning system, truck wash bay and air compressor.

Designed and built by Connolly Brothers Inc. of Beverly, the complex is equipped with energy efficiency utility systems. The 10,000-square-foot office building includes a fitness center, meeting spaces and collaborative workspace.

Founded in 1972, W.L. French has 250 employees and operates more than 275 pieces of heavy equipment.