Resources Numerical accuracy
Calculations
Every calculation under our calculation policies: what it works out, its formula and the precision it runs at. Open one to see its code as it is in the released app.
Calculations
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Weight and center of gravity of a pick
The weight of an assembly and the point its weight acts at.
W = Σ w_i; cg = Σ w_i·(a_i + b_i) ÷ 2 ÷ W
Erection plan: picks, crane loads and times erection.js64-bit- DetailCraft
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Storey a pick belongs to
Which storey a pick is erected with, for the order of the sequence.
Erection plan: picks, crane loads and times erection.js64-bit- DetailCraft
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Load, radius and share of the chart
The load on the hook, the working radius, the chart capacity there and the share of it used.
load = W·(1 + rigging% ÷ 100) + deduction; radius = max(r_pick, r_set); share = load ÷ capacity
Erection plan: picks, crane loads and times erection.js64-bit- DetailCraft
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Time of a pick
How long a pick takes and when it starts and ends.
travel = (plan distance + top height) ÷ 1000; minutes = hook + travel ÷ speed + set + release; start = max(crane free, supports done)
Erection plan: picks, crane loads and times erection.js64-bit- DetailCraft
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Status of a pick
Whether a pick is fine, over the chart, above the chosen limit, out of reach or too high for the hook.
over when share > 1; high when share > limit
Erection plan: picks, crane loads and times erection.js64-bit- DetailCraft
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Plan totals
The total weight, the total time, the heaviest pick and the pick that uses most of the chart.
total kg = Σ W; minutes = max end time
Erection plan: picks, crane loads and times erection.js64-bit- DetailCraft
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Figures in the plan's warnings
The numbers quoted when a pick is over the chart, over the limit or too high.
Erection plan: picks, crane loads and times erection.js64-bit- DetailCraft
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Data handed to the movie
The picks, boxes and times saved into the erection movie page.
Erection plan: picks, crane loads and times erection.js64-bit- DetailCraft
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Concrete strength from the footing's text
The concrete strength in MPa read from text such as 4000 psi, 28 MPa or C30/37.
MPa = psi × 0.00689476
Footing design checks foundation.js64-bit- DetailCraft
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Support reaction as a footing load
Turns an analysis support reaction into the load on the footing in the footing's own axes.
P = F_z ÷ 1000; (V_x, V_y) = rot(−F) ÷ 1000; (M_x, M_y) = rot(−M) ÷ 10⁶
Footing design checks foundation.js64-bit- DetailCraft
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Effective depths
The depth from the top of the footing to the middle of each layer of bottom bars.
d_X = H − c − d_bX ÷ 2; d_Y = H − c − d_bX − d_bY ÷ 2
Footing design checks foundation.js64-bit- DetailCraft
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Service load and its eccentricity
The total vertical load on the soil and where it acts.
W = γ_c·A·h + γ_s·A·fill; N = ΣP + W; e_x = (ΣP·x + ΣM_y + h·ΣV_x) ÷ N
Footing design checks foundation.js64-bit- DetailCraft
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Pressure under a rigid rectangle
The plane of soil pressure under the footing, with part of the base lifting off when the load is outside the kern.
q = a + b·x + c·y; inside the kern: a = N ÷ A, b = 12·N·e_x ÷ (A·L²), c = 12·N·e_y ÷ (A·B²)
Footing design checks foundation.js64-bit- DetailCraft
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Three equations in three unknowns
Solves the Newton step for the pressure plane.
Footing design checks foundation.js64-bit- DetailCraft
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Soil force and moment beyond a cut
The upward soil force on the part of the base beyond a cut, and its moment about the cut.
V = Σ q·dw·ds; M = Σ q·dw·ds·(t − cut)
Footing design checks foundation.js64-bit- DetailCraft
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Demand over capacity
The ratio each check reports and whether it passes.
ratio = demand ÷ capacity; ok when ratio ≤ 1 + 1e-9
Footing design checks foundation.js64-bit- DetailCraft
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Sliding and overturning
The safety factors against sliding on the base and against overturning.
H = √(V_x² + V_y²); sliding: fs·H ≤ μ·N; overturning: FS = 1 ÷ max(|e_x| ÷ (L ÷ 2), |e_y| ÷ (B ÷ 2))
Footing design checks foundation.js64-bit- DetailCraft
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Shear and moment on a cut, and the largest moment
The shear and moment on a cut across the footing, and the cut with the largest moment.
V = V_soil − ΣP; M = M_soil − Σ(P·arm + M_col + h·V_col)
Footing design checks foundation.js64-bit- DetailCraft
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Bending steel
The steel provided per meter, the steel bending needs and the minimum steel.
M_u per m = |M| ÷ (b ÷ 1000) × 10⁶; A_s provided = A_bar × 1000 ÷ s; A_s,min = ρ_min × 1000 × H
Footing design checks foundation.js64-bit- DetailCraft
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One-way shear
The largest shear at a distance d from each column face against the concrete's shear strength.
V_u = max |V| at face ± d; capacity = 0.75 × V_c
Footing design checks foundation.js64-bit- DetailCraft
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Bar development length
The straight length a bar needs beyond the column face to develop its strength.
l_d = max(300, f_y ÷ (k·λ·√f′c) × d_b); k = 2.1, 1.7, 1.4 or 1.1
Footing design checks foundation.js64-bit- DetailCraft
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Hooked bar development length
The length a hooked bar needs.
l_dh = max(8·d_b, 150, 0.24·f_y ÷ (λ·√f′c) × d_b)
Footing design checks foundation.js64-bit- DetailCraft
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Length available for development
The length of bar from the farthest column face to the end of the footing, less the cover.
available = side ÷ 2 − (|x_col| + c_col ÷ 2) − cover
Footing design checks foundation.js64-bit- DetailCraft
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Critical section for punching
The perimeter at d ÷ 2 from a column, cut off at the footing's edge, with its length, centroid and section properties.
b_o = Σ l; J = Σ (d·l³ ÷ 12 + l·d³ ÷ 12 along the bending direction) + d·l·arm²
Footing design checks foundation.js64-bit- DetailCraft
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Punching shear
The shear stress on the critical section against the concrete's punching strength.
v_u = V_u ÷ (b_o·d) + γ_v·M·c ÷ J (both directions); v_c = min(0.33, 0.17·(1 + 2 ÷ β), 0.083·(2 + α_s·d ÷ b_o))·λ_s·λ·√f′c
Footing design checks foundation.js64-bit- DetailCraft
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Share of the base in contact
The share of the base still pressing on the soil when part has lifted off.
share = cells with q > 0 ÷ 1600
Footing design checks foundation.js64-bit- DetailCraft
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Settlement at the corner of a loaded rectangle
The settlement under the corner of a flexible rectangle carrying a uniform pressure on an elastic half-space.
w = q·b·(1 − ν²) ÷ (π·E) × (m·ln((1 + √(m² + 1)) ÷ m) + ln(m + √(m² + 1))); m = long side ÷ short side
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Settlement at the center and corner of a footing
The elastic settlement at the middle and at a corner of the footing.
center = 4 × corner of the quarter rectangle
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Mat mesh size and concrete stiffness
The element size of the plate mesh and the concrete's modulus.
size = max(min(clamp(min(L, B) ÷ 14, 150, 600), max(100, smallest column ÷ 3)), √(L·B ÷ 8000)); E_c = 4700·√f′c
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Soil springs under the nodes
The spring stiffness under each node from the subgrade modulus and the area the node carries.
A = |d₁ × d₂| ÷ 2 (the two diagonals); k_node = k_s × 10⁻⁶ × Σ A ÷ 4
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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A column load spread over its footprint
The force on each node inside a column's footprint.
R_i = P ÷ n + M_y·dx_i ÷ Σdx² − M_x·dy_i ÷ Σdy²
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Mat settlement and contact pressure
The largest and smallest settlement of the mat and the largest spring pressure.
q = k_s × w ÷ 1000; reaction = Σ k_node × w ÷ 1000
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Mat bending moments and shear
The largest sagging and hogging moments per meter each way and the largest transverse shear.
M = max and min of the node moments ÷ 1000; V = max √(q_x² + q_y²) away from the columns
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Hogging capacity of plain concrete
The hogging moment a mat with no top bars can take.
capacity = 0.60 × 0.42·λ·√f′c × (H² ÷ 6) × 1000 ÷ 10⁶
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Spring pressure at a point
The soil pressure at any point of the mat from the settlements of the nodes round it.
q = k_s ÷ 1000 × bilinear blend of the four corner settlements
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Pile group reactions
The load each pile takes under a vertical load and two moments.
R_i = P ÷ n + M_x·y_i ÷ Σy² + M_y·x_i ÷ Σx²
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Cantilever retaining wall
Overturning, sliding and bearing of a cantilever wall with level backfill.
K_a = tan²(45° − φ ÷ 2); P_a = ½·K_a·γ·H_t²; e = B ÷ 2 − (M_r − M_o) ÷ W
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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A real number in the file
How every length, coordinate, direction component and weight is written.
text = toFixed(6), trailing zeros dropped; |v| < 1e-9 → 0
IFC export ifc.js64-bit- DetailCraft
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Storey of an element
Which storey an element is put in: the highest level at or below its lowest point.
level z ≤ lowest point + 0.5 mm
IFC export ifc.js64-bit- DetailCraft
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Placement of a part
The origin and the two axes each part is placed with, relative to its storey.
location = (p_x, p_y, p_z − level z); Axis = part x; RefDirection = part u
IFC export ifc.js64-bit- DetailCraft
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Profile dimensions
The section dimensions written for each profile type.
IFC export ifc.js64-bit- DetailCraft
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Mitre cut plane
The plane that clips a part's extrusion at a mitre end.
normal = unit(−sg·ku, −sg·kv, sg); point = (0, voff, x0)
IFC export ifc.js64-bit- DetailCraft
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Hole openings
The position, direction, depth and radius of each hole's opening.
depth = thickness + 2; start = center − axis·depth ÷ 2; radius = d ÷ 2
IFC export ifc.js64-bit- DetailCraft
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Cope openings
The box that cuts each cope out of a part.
center v = voff ± (depth ÷ 2 − cope depth ÷ 2 + 0.5); box = (width + 2) × (cope depth + 1) × (cope length + 1)
IFC export ifc.js64-bit- DetailCraft
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Bolts and anchor rods
The placement, diameter and length written for each bolt and rod.
IFC export ifc.js64-bit- DetailCraft
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Reinforcing bar center lines
The center line of each placed bar as lines and true arcs, with the bar's radius.
point = origin + s·ŝ + t·t̂; arc through start, middle and end; radius = d_b ÷ 2
IFC export ifc.js64-bit- DetailCraft
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Length and weight properties
The cut length and weight written in each part's property set.
IFC export ifc.js64-bit- DetailCraft
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Length unit to millimeters
The factor that turns the file's lengths into millimeters.
toMm = prefix × 1000; converted units: toMm = factor × prefix × 1000
IFC import ifc-import.js64-bit- DetailCraft
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A placement's axes
The three axes and origin of an IFC axis placement.
Z = unit(Axis); X = unit(Ref − Z·(Ref·Z)); Y = Z × X
IFC import ifc-import.js64-bit- DetailCraft
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Placements combined
One placement expressed inside another.
X′ = A·X, Y′ = A·Y, Z′ = A·Z, O′ = A·O + O_A
IFC import ifc-import.js64-bit- DetailCraft
A calculation is added only after its source was read. Each statement can be checked in the code shown on its policy's page; the app repositories are public. When a release changes a calculation, its page says so until it has been read again.