Threaded rod continuity for bridge deck weight

Precast, prestressed I-girder bridges are generally designed as simple spans for the girder self-weight and deck weight and continuous spans for super-imposed dead and live loads. Because the super-imposed loads are only about one-third of the total load, structural efficiency can be further improved if continuity is achieved for the deck weight. This paper presents a threaded rod continuity system to make precast concrete girders continuous for the deck weight without resorting to posttensioning. The threaded rod continuity system can increase bridge span capacity from 10% to 15% and essentially eliminate possible cracking at the bottom fiber of the pier diaphragm. The threaded rod continuity system allows precast concrete to compete favorably with steel in long-span highway bridges. This paper covers the historical development of the threaded rod continuity system. This paper also includes design criteria, experimental tests, design procedures, system implementation, and a numerical example.