Precast concrete frame construction is not used extensively in seismic regions of the USA. The UBC [ICBO, 1991] currently permits only certain specific building systems to be used and a precast frame is not one of them. The reason is that extensive research on cast-in-place frames has led to the development of reinforcement details that provide suitable ductility, and these details are now prescribed in the UBC. Im most cases, these details cannot be easily achieved in a purely precast system. The result is that most precast structures can be made to satisfy the UBC only under the guise of an "undefined structural system" which must "...be shown by technical and test data which establish the dynamic characteristics and demonstrate the lateral force resistance and energy absorption capacity to be equivalent to systems listed in Table No. 23-O for equivalent Rw values." This requirement makes approval of a precast frame very difficult. In addition, another UBC requirement calls for "reinforcement resisting earthquake-induced" forces to conform to ASTM A 706 and A 615 Grades 40 and 60 specifications which excludes prestressing steel. Since the advantages of precasting and prestressing are interlinked, this provision on prestressing inhibits the use of precast concrete.
Proceedings Title: 4th Joint Technical Coordinating Committee
Conference Dates: May 16-17, 1994
Conference Location: Tsukuba,
Conference Title: Precast Seismic Structural Systems
Pub Type: Conferences
concretes, beams, columns, tests, construction, structural systems, dynamic characteristics