Glulam timber bridges are viable and cost-effective options for replacing bridges on low-traffic county and township roads. That’s what South Dakota State University researchers at the J. Lohr Structures Lab concluded after testing a full-scale glulam timber girder bridge. Glulam, short for glued laminated, means the structural members are made of layers of wood strips bonded with glue. The girder bridge, which was made of Southern Yellow Pine, showed satisfactory performance and minimal damage under cyclic loading equivalent to 75 years of service, explained assistant civil engineering professor Mostafa Tazarv, structures lab coordinator and co-principal investigator for the project.  “To our knowledge, this is the first time that full-scale testing has been done on glulam timber bridges,” he said.