Acknowledgments
This study was supported by National Natural Science Foundation of China (51408116 and 51278120), Natural Science Foundation of Jiangsu Province (BK20140630), and Transportation Research Program of Jiangsu Province (2014Y01). The financial supports are greatly appreciated.
Notation
The following symbols are used in this paper:
Av = cross-sectional area of one stirrup; a = shear span;
bw = web width of beams;
d = effective depth of beams;
dv = effective shear depth of beams, dv ≈ 0.9d; fc0 = specified compressive strength of concrete;
fck = characteristic compressive cylinder strength of concrete, fck ≈ 0.9fc0;
fy = yield strength of reinforcing steel; sv = spacing of shear reinforcement;
Vu = ultimate shear capacity of beams;
V−u = lower bounds of shear capacity of beams;
V shear strength controlled by the crushing of inclined concrete struts;
Vs = shear strength controlled by the yielding of shear reinforcement;
ε1, εx = principal and longitudinal strains;
ω = mechanical shear-reinforcement ratio, ω ¼ ρvfy=fc0;
ρv = ratio of shear reinforcement, ρv ¼ Av=ðbwsvÞ; and θu = inclination of diagonal struts at ultimate;
ν = efficiency factor of compressive strength of concrete;