Wall Anchor Connection Test

The tests in Phase IV of the NEES-Anchor project was design to verify if the code-conforming anchor reinforcement is sufficient to support the anchor connections in plastic hinge zones of a reinforced concrete (RC) wall. Specifically, two 4-stud connections were installed in the boundary elements of a 1/2-scale concrete wall, likely to be used in 20-story buildings with RC core walls and steel frames. The concrete wall specimen was 10 ft tall and the cross section was 10 x 60 in. The anchor connections were within the plastic hinge zone of the concrete wall, which was expected to develop significant damage during the simulated seismic loading. The existing design code recommends U-shaped hairpins, therefore, closed ties and additional J-hooks were used as anchor reinforcement in the test. The wall was subjected to a axial compression, equivalent to 10 percent of its axial load capacity before being subjected to cyclic loading in displacement control on its top. The generated shear force (story shear) was applied to the anchor connections through two hydraulic actuators.