, Precast concrete frames structures offer momentous advantages compared to cast in place reinforced concrete structures, which has led to a considerable global increase its market. In these type of frames, constructability, strength, ductility and strength hinge upon the behavior of the connections. A viable solution that facilitates construction and also satisfies structural requirements can make a difference in the structural and also economic output. Architectural aspects also are of importance. In this research, the proposed connections are designed not only to minimize construction time and labor work, also satisfy the required acceptance criteria of ACI 374-2005 for new connection details. During the construction period, semi precast beams were placed on corbels, partly embedded inside the continuous columns. This will remove the need for shoring and temporary bracing to hold the precast unit in place and during the erection of the precast components. Furthermore, the hidden corbel addresses the architectural drawback of ordinary concrete corbels. This research is aimed to introduce five new type of precast connections to join the semi precast beam to a continuous precast column with hidden corbel protruding from its side for the purpose by bolting or welding. This system has been designed to provide for rapid in site assembly without using concrete corbels. Five type of precast concrete semi precast beam to continuous precast column, designed for developing seismic loads in precast frames, were designed and proposed. The proposed connections consisted of semi precast beam with recede section, with threaded bars at top in all connections, and threaded bar or non threaded bars at bottom, bolted or welded to the corbel in precast continuous column. The specimens in each type of connections with two different longitudinal reinforcement and two monolithic reference specimens were tested under reversed cyclic loading (12 specimens). Variables included the amount of longitudinal reinforcement in the beams and shape of corbels. The proposed precast connection provides good structural integrity in the connections and can reduce construction time by eliminating the need for formworks and minimizing cast-in-place concrete volume. Hysteresis loops, strength, stiffness degradation, damping, energy dissipation and ductility of the precast specimens have been compared to those of the corresponding monolithic connections. Three types of the new proposed precast connection satisfied all of the acceptance criteria for moment frames based on structural testing in ACI374-2005. Keywords: Precast structures, Beam to column precast connections, Energy dissipation, Stiffness degradation, Ductility, Lateral strength, ACI374-2005
