Our History

Mason (right) and Aubrey (Pete) Henley take benchmark readings at an excavation site in Dallas, TX circa 1966

Since its establishment in 1951, our firm has offered and developed a wide range of technical expertise and special qualifications involving the geologic formations and settings found in the Southwest and the impact these subsurface conditions have on the built environment.

Raymond C. Mason, P.E. and Floyd T. Johnston, P.G. co-founded the firm as Mason-Johnston & Associates, Inc. after successful careers with the United States Army Corps of Engineers. In 1991, the firm name evolved into Henley-Johnston & Associates, Inc. (HJA) as Aubrey (Pete) Henley, P.G. and John W. Johnston, P.E. became principal and managing shareholders of the firm.

The principals and staff of HJA have completed over 20,000 projects and have provided consulting services for over 80 percent of the high-rise construction in the Dallas Central Business District and the Uptown area within the last 70 years. Our breadth of experience includes large-scale and small-scale retail projects, single-family residential and apartment developments, custom built homes, schools, and transportation related studies. HJA has also completed several hundred water transmission and storage projects, as well as numerous medical facilities and hospitals. HJA has also worked on multiple projects internationally; including consulting on the construction of the Serre Poncon Dam in France in 1952 and the Alta Shopping Center in Sarajevo, Bosnia.

Tri-axial test apparatus circa 1970

Henley-Johnston is proud to have been an integral part of Dallas history. Many of the projects we have worked on have become a part of the Dallas skyline. Past work has included the original studies for the Dallas/Fort Worth Airport; Kennedy Memorial; Jefferson Street Viaduct; Dallas Police Memorial; CityPlace; One Main Place; consulting and testing services for the Comanche Peak Nuclear Power Reactor and Squaw Creek Dam; the southern section of the Dallas North Tollway; testing services for the Super Conducting Super Collider; the US 75/Central Expressway DART Tunnel; and the American Airlines Hospitality Complex. HJA has also conducted all the subsurface investigations for the Dallas Convention Center beginning with the Dallas City Auditorium in 1957 and the subsequent expansions and additions. Historic projects outside of downtown proper include work on the original Cowboys Stadium in 1971, expanding the Music Hall at Fair Park, the Dallas Galleria, and various expansions and exhibits at the Dallas Zoo.

1970’s Field Exploration with Failing rotary drill rig

More recent projects include geotechnical consulting, and in most cases, construction materials testing for the new Celina High School; Phases 1, 2 and 3 of the Crescent Plaza/Ritz Carlton development; the 2000 McKinney Office Tower; Children’s Medical Center and Methodist Hospital; Blocks D, J, L, and M of the Victory Park Development; Block 51 in Austin, Texas; Main Street Garden Park for the City of Dallas; Custer Road Pump Station for the City of Plano; The Omni Hotel; and 1400 Hi Line Residential Tower on Stemmons Freeway in the Dallas Design District.