Abstract: An insert is disclosed for insertion into a U-shaped channel member for supporting hangers carrying cables, pipes, conduits and the like. The U-channel is a structural support element which is secured to a suitable substrate or, more commonly, embedded in concrete walls. The insert includes a main body portion of greater length than width having a threaded bore therethrough for insertion of a bolt therein, the bolt holding the support member in place. The insert also includes integral resilient legs extending from the rear wall of the insert and contacting the rear wall of the channel member, the legs biasing the insert forwardly against the side walls of the channel member.