Salas O’Brien announced the merging of San Diego-based companies T-Squared Professional Engineers and Axiom Commissioning Group with its business. The combined firm of 17 offices includes approximately 500 employee-owners and 120 registered professionals across the nation, Salas O’Brien said.

The transaction closed on Feb. 1. The terms of the deal were not disclosed.

Salas O’Brien said that T-Squared and Axiom will continue to be managed locally by their current leaders and will adopt the Salas O’Brien name after a transition period.

The combined company plans to develop its presence in higher education, hospitality, critical environments, healthcare, industrial, K-12, government, power transmission and distribution, and telecommunications.

Salas O’Brien is a facility planning, design, construction management, and commissioning firm with offices dispersed nationwide. Its CEO and corporate controller are based in Santa Ana, California.