High Quality Content by WIKIPEDIA articles! Simpson Gumpertz & Heger Inc. (SGH) is a privately held ENR 500 engineering firm that designs, investigates, and rehabilitates structures and building enclosures. Their work encompasses building, transportation engineering, water-wastewater, and nuclear, science, and defense projects throughout the U.S. and over twenty foreign countries. SGH has 400 employees at five offices in Boston, Los Angeles, New York City, San Francisco, and Washington, D.C.