Shore Tower Design Calculator

Calculate shore post spacing and load from slab thickness and shore capacity.

Slab thickness (in)

Concrete unit weight (pcf)

Shore capacity (lbs)

Construction live load (psf)

Form dead load (psf)

Bay size (ft)

Tab to move between fields

Total design load (psf)

157

Concrete dead load (psf)100

Max shore spacing (in)67.7

Practical spacing (in)66

Actual shore load (lbs)4,749

Shore utilization (%)95

Shores per bay25

Bay total load (lbs)62,800

How to Use This Calculator

Enter Slab Thickness in inches, Concrete Unit Weight, and Shore Capacity per post.
Enter Construction Live Load in psf (minimum 50 per ACI 347), Form Dead Load, and Bay Size.
Review Total Design Load in psf and Max Shore Spacing to lay out the shoring grid.
Check Practical Shore Spacing, Shore Utilization percentage, and Shores Per Bay.
Use Bay Total Load in pounds to verify the capacity of stringers and joists spanning between shores.

How the result changes with Slab thickness (in)

Slab thickness (in): Thickness of the concrete slab to be poured.
Concrete unit weight (pcf): Unit weight of concrete. Normal weight: 145-150 pcf.
Shore capacity (lbs): Safe working load of each individual shore post.
Construction live load (psf): ACI 347 minimum: 50 psf for workers/equipment. Use 75 psf for motorized carts.
Form dead load (psf): Weight of plywood, joists, and stringers. Typically 5-10 psf.
Bay size (ft): Bay dimension (assumed square) for estimating total shores per bay.

Concrete dead load (psf): Weight of the concrete slab per square foot.
Total design load (psf): Combined dead + live load on the shoring system.
Max shore spacing (in): Maximum center-to-center shore spacing based on capacity.
Practical spacing (in): Recommended spacing rounded down to nearest 6-inch increment.
Actual shore load (lbs): Load on each shore at the practical spacing.
Shore utilization (%): Percentage of shore capacity used at practical spacing.
Shores per bay: Total number of shores needed for one bay.
Bay total load (lbs): Total vertical load on shoring for one bay.

Identify Input Parameters
4 parameters
Slab thickness (in) = 8, Concrete unit weight (pcf) = 150, Shore capacity (lbs) = 5000, Construction live load (psf) = 50 = 6 input(s) provided
Calculate Total design load
Total design load = concreteDL + formDeadLoad + constructionLL
157 = 157
Calculate Concrete dead load
Concrete dead load = (slabThickness / 12) * concreteWeight
100 = 100
Calculate Max shore spacing
Max shore spacing = maxSpacingFt * 12
67.7 = 67.7