Formulas: Filled Composite Members

Formula 1

$b_i = B - 2t_w$ (text_label - position: above the cross-section diagram)

b_i = B - 2t_w

Formula 2

Neutral axis location for force equilibrium: $\mathbf{a}_{p}=\frac{2 F_{y} H t_{w}+0.85 f_{c}^{\prime} b_{i} t_{f}}{4 t_{w} F_{y}+0.85 f_{c}^{\prime} b_{i}}$

\mathbf{a}_{p}=\frac{2 F_{y} H t_{w}+0.85 f_{c}^{\prime} b_{i} t_{f}}{4 t_{w} F_{y}+0.85 f_{c}^{\prime} b_{i}}

Formula 3

| Steel Stress | Stress at $y = a_y$ | $0$ |

y = a_y

Formula 4

| Steel Stress | Stress at $y = 2a_y$ | $F_y$ |

y = 2a_y

Formula 5

Neutral axis location for force equilibrium: $\mathbf{a}_{y}=\frac{2 F_{y} H t_{w}+0.35 f_{c}^{\prime} b_{i} t_{f}}{4 t_{w} F_{y}+0.35 f_{c}^{\prime} b_{i}}$

\mathbf{a}_{y}=\frac{2 F_{y} H t_{w}+0.35 f_{c}^{\prime} b_{i} t_{f}}{4 t_{w} F_{y}+0.35 f_{c}^{\prime} b_{i}}

Formula 6

Neutral axis location for force equilibrium: $\mathbf{a}_{c r}=\frac{F_{y} H t_{w}+\left(0.35 f_{c}^{\prime}+F_{y}-F_{n}\right) b_{i} t_{f}}{t_{w}\left(F_{n}+F_{y}\right)+0.35 f_{c}^{\prime} b_{i}}$

\mathbf{a}_{c r}=\frac{F_{y} H t_{w}+\left(0.35 f_{c}^{\prime}+F_{y}-F_{n}\right) b_{i} t_{f}}{t_{w}\left(F_{n}+F_{y}\right)+0.35 f_{c}^{\prime} b_{i}}

Found in

FLEXURE