Experimental Study Of Steel Reinforced Concrete Src Coupling Beams Under Nonlinear Wind Demands

The recently-published ASCE/SEI Prestandard for Performance Based Wind Design (ASEC/SEI, 2019) describes design for modest nonlinear response of select structural members such as coupling beams. In this study, two steel reinforced concrete (SRC) coupling beams, with steel sections that embedded into a reinforced concrete wall, were tested quasi-statically under fully reversed cyclic wind demands with peak beam deformation of three times the yield rotation. The beams and walls were designed in accordance with AISC 341-22 Section H5, and the wall was compliant with ACI 318-19 Section 18.10.6.5. The beam and wall for each test was nominally identical, with the only test variable being the wall demand. During each test, the wall was subjected to constant axial gravity load and fully reversed-cyclic lateral loading that was linearly proportional to the load in the test beam. The ratio of wall shear to beam shear was constant for the two tests, while the wall moment at the height of the coupling beam produced by the applied wall demands differed by a factor of 2.0 for the two tests. Damage in the two test beams concentrated at the beam-wall interface, with the majority of the coupling beam deformation at this location. The number of cycles used in the tests was substantially higher than that used in typical seismic tests. Despite the significant stiffness degradation for repeated loading cycles at a given increment, significant strength degradation of initial cycles at new peak deformation demands or pinching in the load-deformation response was not observed. In both tests, peak load resistance was reached at peak deformation demand, which was 5.70% and 4.80% chord rotation for the two tests.