Concrete Beam Design (CHAPTER 9 ACI 318-14)100% ACCURATE

Concrete Beam Design (CHAPTER 9
ACI 318-14)100% ACCURATE
Nominal Flexural Capacity ϕMn - ANSWERa = As∙fy/(0.85∙f'c∙b)
ϕMn = ϕAs∙fy∙(d-a/2)
ϕ = 0.9

Area of Steel Required (Quick formula) - ANSWERAs = Mu / 4d
Mu (kip-ft)
d (in)

Min. Ratio of Steel - ANSWER9.6.1.2 (ACI 318-14)
ρmin = 3∙f'c^0.5/fy
ρmin = 200/fy


Maximum Spacing of shear reinforcement - ANSWER9.7.6.2.2
s = min(d/2, 24in)

Specified Concrete Cover Requirements
Cast against and permanently in contact with ground
Exposed to weather - ANSWER20.6.1.63 (ACI 318-14)
- Cast against and permanently
in contact with ground - All Members - 3"
- Exposed to weather or in contact
with ground - All Members- #6 to #18 - 2"
- Exposed to weather or in contact
with ground - All Members- W31 to #5 - 1.5"
- Balance Ratio of Steel
- Max Ratio of Steel
- Max.Tension Control Ratio of Steel - ANSWERρbal=[87000/(87000+fy)]∙(0.85∙β1∙f'c)/fy
ρmax = 0.75∙ρbal
ρmaxt = 0.319·β1·f'c/fy

Minimum flexural reinforcement spacing - ANSWER25.2 (ACI 318-14)
1" or 1 bar diameter

Minimum Beam Depth - ANSWERTable 9.3.1.1 (ACI 318-14)
Simple Supported L/16
One end continuous L/18.5
Both end continuous L/21
Cantilever L/8

Shear Capacity ϕVn - ANSWER22.5.5.1