Experimental Study of Moving Beam Plastic Hinging Zones for Earthquake Resistant Design of R/C Buildings.

Current design practice usually leads to the formation of plastic hinges in the beam regions adjacent to the column and consequently causes stiffness and strength deterioration to take place in the joint. Joint deterioration can be eliminated by moving beam yielding away from the connection. A technique for moving the plastic hinging zone one effective beam depth away from the column face was experimentally investigated. In this investigation, twelve full size interior beam-column subassemblages were tested under quasi-static loading which was intended to simulate earthquake input. Eight of the subassemblages consisted of beams and columns only and the other four also had transverse beam stubs and slabs. All specimens were designed following the accepted strong column-weak beam philosophy. The main objectives of the investigation were: (1) to examine the effectiveness of using intermediate longitudinal reinforcement in the beam over a specific length on both sides of the joint for moving the plastic hinge away from the joint, and (2) to suggest a simple design procedure for assuring that the plastic hinge will develop at a reasonable distance from the joint. On the basis of the test results it was concluded that intermediate longitudinal beam reinforcement combined with extra top and bottom steel in the beam over a specific beam length adjacent to the joint can successfully move the plastic hinge away from the column face, provided that the joint shear force introduced by the intermediate reinforcement does not exceed 30 percent of the total developed joint shear force and the beam shear span to depth ratio is greater than 3.PhDCivil engineeringUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/160753/1/8600393.pd