Single footing, strip footing and mat foundations are designed automatically according to ACI Chapter 13.
Ag = gross area of concrete section, in2
As = area of nonprestressed longitudinal tension reinforcement, in2
Ec = modulus of elasticity of concrete, psi
Es = modulus of elasticity of reinforcement, psi
fc' = specified compressive strength of concrete, psi
fy = specified yield strength for nonprestressed reinforcement, psi
Mu = factored moment at section, in.-lb
β = ratio of long to short dimentions; clear spans for two-way slabs, sides of column, concentrated load or reaction area; or sides of a footing
γs = factor used to determine the portion of reinforcement located in center band of footing
According to ACI 22.214.171.124, minimum foundation effective depth of bottom reinforcement is 6 inches.
According to ACI 126.96.36.199, in sloped, stepped, or tapered foundations, depth and location of steps or angle of slope should be such that design requirement are satisfied at every section.
One-way Shallow Foundations
According to ACI 188.8.131.52; one way shallow foundations including strip fooings, combined footings and grade beams should be designed in accordance with the appliacable provisions of ACI Chapter 7 (One-Way Slab Design) and ACI Chapter 9 (Reinforced Concrete Beam Design per ACI 318-19).
According to ACI 184.108.40.206; reinforcement should be distributed uniformly across entire width of one-way footing.
Two-way Isolated Foundations
According to ACI 220.127.116.11; two-way shallow foundations should be designed in accordance with the appliacable provisions of ACI Chapter 7 (One-Way Slab Design) and ACI Chapter 8 (Two-Way Slab Design).
According to ACI 18.104.22.168; reinforcement should be distributed uniformly across entire width of two-way footing in both directions.
According to ACI 22.214.171.124; in rectengular footing, reinforcement should be distributed in accordance with two conditions given below;
Reinforcement in the long direction should be distributed uniformly across entire width of footing.
Reinforcement in the short direction, a portion of the total reinforcement, γsAs, should be distributed uniformly over a band with equal to the length of short side of footing, centered on centerline of column or pedestal. Remainder of reinforcement required in the short direction, (1-γs)As, shall be distributed uniformly outside the center band width of footing, where γs is calculated by ACI Eq. (126.96.36.199),
Two-way Combined Footings and Mat Foundations
According to ACI 188.8.131.52; two-way shallow foundations should be designed in accordance with the appliacable provisions ACI Chapter 8 (Two-Way Slab Design).
According to ACI 184.108.40.206; Distribution of bearing pressure under combined footings and mat foundations should be consistent with properties of the soil or rock and the structure, and with established principles of soil or rock mechanics.
According to ACI 220.127.116.11; minimum area of flexural reinforcement in nonprestressed mat foundations is satisfied near the tension face of the slab in the direction of the span, As,min=0.0018Ag
Walls as Grade Beams
According to ACI 18.104.22.168; walls as grade beams should be designed in accordance with the appliacable provisions of ACI Chapter 9 (Reinforced Concrete Beam Design per ACI 318-19).
According to ACI 22.214.171.124; walls as grade beams should satisfy the minimum reinforcement requirement of ACI 11.6.
According to ACI 11.6.1, If in-plane Vu ≤ 0.5ϕαcλ√fc‘Acv, minimum ρl and ρt should be in accordance with ACI Table 11.6.1.
According to ACI 11.6.1, If in-plane Vu ≤ 0.5ϕαcλ√fc‘Acv, two conditions given below should be satisfy;
ρl should be at least the greater of the value calculated by ACI Eq. (11.6.2) and 0.0025
Minimum value of ρt should be 0.0025
Critical sections for shallow foundations and pile caps
According to ACI 126.96.36.199, Mu at the supported member can be calculated at the critical section defined in accordance with ACI Table 188.8.131.52.
Development of reinforcement in shallow foundations
According to ACI 184.108.40.206, development of reinforcement should be in accordance with Development of Reinforcement title.