The test specimens were divided into three series according to
concrete strength fc, resulting in L-series for fc = 24 MPa,
H-series for fc = 50 MPa, and UH-series for f c = 80 MPa.
Under each concrete series, the shear span-to-depth ratio, the
width of opening m1a , and the depth of opening m2 h were
established as test variables. The shear span-to-depth ratios in
L- and H-series beams were chosen as 0.5 and 1.0, and in UH-
series 0.5, 0.7, 1.0 and 1.5. The widths of opening were taken
as 0.25a, 0.5a and 0.65a in H- and UH-series, and 0.5a only
in L-series. And the depths of the opening were selected as
0.1h , 0.2h and 0.3h in H- and UH-series, and 0.3h only in
L-series. The center of the web openings of all beams was
positioned at the center of the shear span region as shown in