超筋 T tp 了5 45 适筋 斜扭破坏面 的下联选 少筋 斜裂缝 临界斜裂缝 背面螺 正面螺 旋裂缝 旋裂缝 Conception of“Lake reinforced member”?(少筋) Steel yield as soon as cracking of concreteρ T 少筋 适筋 超筋 Conception of “Lake reinforced member” (少筋） Steel yield as soon as cracking of concrete