Flexure strength vs.steel ratio Strain profiles ☑☑ Steel 10 09 00 egion B-C: 0 0A- 000m 土本又程学院 T特N力N时门度事 6
6 Flexure strength vs. steel ratio 6
Basic Assumptions l.“Plane sections remain plane'”assumption A 8 dy Snho ho (1-5n)ho ●● 6 6 nho y ho-as' (1-5m)h 目土本工程学汽
7 7 0 0 0 ' (1 ) ' h y h a n h s n s c s n t c e e e e f − = − = = = as As e c t b h As ’ as ’ y dy et b es es ’ e c f nh0 (1- n )h0 h0 1. “Plane sections remain plane” assumption Basic Assumptions
191 0.004 Column B-3a Column A-15b e=5.0in 0.002 e=12.5in Yield 75 kips =4850 psi point 卷r:0.003 =125.9 kips 125 kips =79.0 kips 60 0.001 40 0.002 90 20 0 0.001 60 ( 30 0.001 Yield 0.001 0.002 Yield point> Column B.2a 0.002 210 kip Column A-20b e=2.5 in f6=4250ps1 e=15.0 in =213 kips =5000ps1 0.001 180 ma-63.5 kips 0 120 60 0.001 Yield point 土本工程学院 特 8
8 8
Basic Assumptions 2.Tensile strength of concrete is neglected in calculation of flexural strength. d M Soho (1-5n)ho 6 3.The strain in the reinforcement is equal to the strain in the concrete at the same level. 目土本工程学院 9
9 9 2. Tensile strength of concrete is neglected in calculation of flexural strength. M T xc Tc C 3. The strain in the reinforcement is equal to the strain in the concrete at the same level. e c t et b es es ’ e c f nh0 (1- n )h0 Basic Assumptions
Basic Assumptions 4.Constitutive laws f o。=f1-(1-6)] 0 o。=fc 80≤8≤Em 0 O=E,88≤8y 0=f)8>6,y o,=E,6 土水工程学院 得 10
10 10 4. Constitutive laws c c cu n c c f f e e e e e e e = = − − 0 0 0 [1 (1 ) ] σ ε0 εu fc y y s y f E e e e e e = = s es s=Eses e y esu fy Basic Assumptions