KJWW Engineering Consultants, a 54-year-old firm based in Rock Island, Ill., with an office in Urbandale, has merged with California-based TTG Corp. The merger creates a 900-employee workforce spread across 25 national and five international locations, according to a release. The firms will continue to operate as KJWW and TTG under the creation of a holding company with common management. TTG Engineering was founded in 1955 in Pasadena, Calif. Individually, the companies are ranked among the top engineering firms by various construction trades organizations. The Des Moines Public Library is among KJWW’s notable projects in Greater Des Moines.