Attività

Two experimental research programs were carried out. One was the experimental study in which the influence of the axial force and the partitioning web were investigated, another was that in which the influence of the opening was investigated.

In the former program, nine specimens were loaded in cyclic in-plane shear. The test parameters were the thickness of the surface high building steel plate, the effects of the partitioning web and the axial force. The experimental results were compared with the calculated results, and good agreement between the calculated results and the experimental results was shown.

In the later programs, six specimens having an opening were loaded in cyclic in-plane shear, and were compared with the results of the specimen without opening. FEM analysis was used to supplement experimental data. Finally, we proposed the equation to calculate the reduction ratio from the opening for design.

Four scaled one-storey single-bay steel plate shear wall  specimens with unstiffened panels were tested to determine their behaviour under cyclic loadings. The shear walls had moment-resisting beam-to-column connections. Four different vertical loads, i.e., 300 kN, 600 kN, 900 kN, and 1200 kN, representing the gravity load of the upper storeys were applied at the top of the boundary columns through a force distribution beam. A horizontal cyclic load was then applied at the top of the specimens. The specimen behaviour, envelope curves, axial stress distribution of the infill steel plate, and shear capacity were analyzed. The axial stress distribution and envelope curves were compared with the values predicted using an analytical model available in the literature.

However, until today, physical experiments on the cyclic behaviour of SPSWs under concurrent gravity and horizontal load have not been reported. Most investigations were performed numerically, e.g., Elgaaly and Liu compared the shear carrying-capacity of a SPSW with and without gravity load by the finite element method. The authors concluded that the gravity load has little effect on the shear-carrying capacity. This might be caused by the low magnitude of compression and thin infill wall considered in their analyses. Zhang and Guo performed finite element analyses on the behaviour of SPSWs with precompression from the adjacent columns. Their research showed that the shear capacity of SPSWs was significantly impaired by the precompression. Their previous research also showed that the gravity load acting at the top of the boundary columns has significant effects on the shear load-carrying capacity.

To evaluate the adequacy of an analytical model available in the literature in predicting the influences of gravity loads on the cyclic performance of the SPSW, physical experiments were performed in this paper. Four scaled SPSWs under compression-shear interaction were designed and tested. The envelope curves, the axial stress distribution and the maximum shear capacity obtained from the experiments were then used in the evaluation of the analytical model.

The test parameter was the vertical load applied at the top boundary columns. Test specimens are one-storey walls. The height of the specimen was 0.75 m, and the width was 1.1 m. The columns were 1 m apart from center to center. Figure 1 shows the size and configuration of the specimens. The plate thickness was 2.1 mm Q235 steel with the yield strength of 255 MPa. The size of the infill plate was 600 mm × 900 mm. The frame members are built-up sections made of Q345 steel with the yield strength of 460 MPa. The boundary columns, i.e., H-overall depth (d) × flange width (bf) × web thickness (tw) × flange thickness (tf), have, respectively, the dimensions of 100 mm × 100 mm × 6 mm × 8 mm. The top beam, connected to the actuator, has the corresponding dimensions of 150 mm × 100 mm × 6 mm × 9 mm. This beam was stiff to ensure a smooth transfer of the load to the tension field occurred below the beam. Moment connections were used at all beam-to-column joints. Connection of the beam flanges to the columns was constructed using complete penetration groove welds. The beam webs were welded to the column flange by two-sided fillet.

Figure 1 shows a sketch of the test specimen with the vertical load and the lateral cyclic load. The constant vertical load of specimens A, B, C, and D was, respectively, 300 kN, 600 kN, 900 kN, and 1200 kN. It was kept steady during the whole test. The beam that distributed the vertical load was hinged to the top of the two boundary columns. A hydraulic jack generated the vertical load at the top of the load distribution beam. It was supported by a stiff steel frame. To avoid any shear force, a roller was placed between the steel frame and the hydraulic jack.