الفهرس 
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Abstract
The beam column joint is the critical zone in a reinforced concrete moment resisting frame. It is subjected to large forces during severe ground shaking and its behavior has a significant influence on the response of the structures. The available lengths of steel bars in the market make it necessary linking the bars for the construction of most reinforced concrete (RC) structures. Reinforcing bars may be welded together or use a form of mechanical coupling, but for economic reasons two bars are often simply overlapped for a distance to create a lap splice. The present work aims mainly to carry out an experimental investigation to compare the behavior of exterior joints with lap splice reinforcement detailed as per (ECP 203-2007) with the continuous reinforcement details; the detailing of column main reinforcement was chosen as the major variable parameter.The experimental program included seven concrete beam-column joints with the same concrete grade, dimensions and with different reinforcement details. Seven 2/3 scale exterior reinforced beam-column joints were tested under the effect of low fatigue cyclic loading. One sample was served as control sample, designed according to the provisions of (ECP 203-2007) where column main reinforcement was deformed bars. Columns in another three samples were detailed with well-confined short lap-splice longitudinal reinforcement (plain or deformed bars) and latest three samples of Columns were detailed with well-confined short lap-splice longitudinal reinforcement (plain or deformed bars) with an additional FRP bars in joint region. The specific objectives of this study can be summarized as follows: Study the effect of the length of lap splice in column main steel reinforcement on the behavior of exterior beam – column joint under the seismic action, Study the effect of steel type (ripped or smooth) on exterior beam- column joint behavior under seismic action. And Study the effect of adding FRP bars in joint region in case of ripped and smooth bars on exterior beam column joint behavior under seismic action. Based on the test results of the seven beam-column joints tested in the experimental phase, the following conclusions can be draw out: Lap-splicing was highly effective in reducing the shear contribution of the joint, longitudinal strains in the longitudinal reinforcement of the column decreased when lap-splice details were used above the joint, The shorter the length of spliced bars, the higher the increase in the energy dissipation of the beam-column joint (33% and 15% for 15d and 20d respectively), Specimens reinforced with well-confined short lap-spliced bars (20d and 15d) were able to continue resisting loads higher than that of the R-CO specimen by 17% and 25%, respectively and Damage level in the serviceability state could be highly reduced when FRP bars were used as damage-controllable bars inside the joint and doweled in both the upper and lower columns.