Image Number 6 for United States Patent #5537794.
An apparatus is disclosed for joining structural units. A structural unit, such as a precast concrete section of pipe, decking, bridge structure, building structure, or pavement, includes a plurality of spaced, longitudinally aligned tubular members. The ends of each structural unit are flush, and the ends of the tubular members are flush with the ends of the structural units. When two of such units are to be joined together, a guide member is inserted in one end of each of the first tubular members in the first structural unit, while an internally threaded insert member is inserted into a corresponding end of each tubular member in the second structural unit. The guide members and insert members have axial apertures with the aperture in the insert member being internally threaded. The two structural units are brought together so that each guide member on the first structural unit enters into the corresponding end of the tubular members containing the inserts in the second structural unit. A bolt is passed through each guide member and is threaded into the internally threaded aperture in the insert member. The bolts are tightened to join the two structural units together. A resilient gasket is cast into one end of a structural unit when it is formed or it is inserted into a groove which is formed in a face of a structural unit at the time the structural unit is formed. The resilient gasket is compressed between the surfaces of the two concrete sections thus forming a face seal at the joint therebetween. A method of assembling the structural units, and also a method of installing the structural units by jacking, are also disclosed.