PERFORMANCE OF COUPLING BEAMS WITH OPENINGS EXPOSED TO CYCLIC LOADING

Sayed, Abd El-Azim; A. Haggag, Hesham; M. Hassan, Wael

doi:10.21608/erj.2020.140846

PERFORMANCE OF COUPLING BEAMS WITH OPENINGS EXPOSED TO CYCLIC LOADING

Document Type : Original Article

Authors

¹ Researcher, Faculty of Engineering, Helwan University, Egypt

² Professor of Structural Engineering, Civil Engineering department, Faculty of Engineering, Helwan University,

³ Associate Professor, Structural Engineering, Housing and Building National Research Center, Egypt

10.21608/erj.2020.140846

Abstract

The performance of coupling beams under cyclic loadings is evaluated when they
have openings with different configuration. The study is performed through
experimental examination on four reduced scale coupling beams. The testing is done
in the Concrete Laboratory at the Housing and Building National Research Center,
Cairo, Egypt. Square openings are constructed on three specimens with different
configurations whereas the fourth specimen kept without openings for the
comparison matter. Two openings are fabricated at top and bottom of the diagonal
bars in one beam specimen. Another specimen contains two openings at left and right
of the diagonal bars. The last specimen has four square openings placed at top-bottom
and left-right of the diagonal bars of the coupling beam. The yield and ultimate tensile
strength of the reinforcement steel bars are 510 and 720 MPa, respectively with
elastic modulus of 200 GPa. The concrete characteristic strength is 38 MPa. All
specimens were tested under laterally cyclic loading to simulate the subjected loads
on coupled shear walls. A special complicated setup is utilized for that issue. The
results are recorded during testing and at the end of each cycle. The forcedeformation
relationships are recorded and their corresponding hysteresis loops are
plotted. The cracks patterns are also marked and recorded. From the obtained results,
one may observe that, in case of using two openings located at right and left (near the
shear walls), the stiffness of the coupling beam is slightly decreased. The coupling
beams stiffness is decreased by ~8.5% for the other pattern of two openings and by
~13.5% in case of using four openings.

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