الفهرس 
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Abstract
An experimental program was designed to study the effect of openings on the seismic behavior of coupling beams at the Reinforced Concrete Laboratory at the Housing and Building National Research Center, Cairo, Egypt. The research program constituted of two phases; construction and testing of four 40%-scale coupling beam specimens; and synthesizing a numerical finite element model to validate and verify the experimental results.
The reinforcement steel bars used with a nominal diameter of 10 mm for stirrups, 12 mm for end blocks which represent the shear wall effect and 16 mm for reinforcing the diagonal bundles. The bars were tested and their mechanical properties were determined in the laboratory. The average yield tensile strength was 566, 525.8 and 437 MPa respectively and ultimate tensile strength was 780, 734 and 675 MPa, respectively; while the average elastic modulus was 200 GPa.
Twelve reinforced concrete specimens with a characteristic strength of 38 MPa and reinforced by diagonal bars system were analytically investigated. Four specimens were constructed and experimentally investigated. The first of them had no openings, the second specimen contained two openings located at top and bottom of the beam, the third specimen also had two openings but located at the right and left of the beam and the fourth specimen had four openings located at top, bottom, right and left of the beam. All specimens were tested under cyclic loading. The force-deformation behavior, strains and crack pattern were investigated. from the results obtained, it was observed that in case of using two openings with different location possibilities, the stiffness of the coupling beam slightly decreases resulting in a decreased coupling between the linked shear walls. In the case of using four openings, it was observed that the stiffness of the coupling beam slightly decreased also in addition to a noticeable increase in its ductility which also implies a decreased coupling of the linked shear walls.