Soil Load & Traffic Calculators

Soil Classification & Properties
Applied Load
Ult. Bearing Capacity (qu)
kN/m²
Allowable Bearing (qall)
kN/m²
Applied Bearing Pressure
kN/m²
FoS Achieved
Net Bearing Pres (q_net)
kN/m²
Min Foundation Area Req
Bearing FactorValueφ UsedDescription
Allowable Bearing Capacity Guidelines (BS 8004 / Eurocode 7): Hard rock: 5,000–10,000 kN/m² | Dense gravel: 400–600 kN/m² | Medium dense sand: 100–200 kN/m² | Firm clay: 75–150 kN/m² | Peat: <25 kN/m² (unsuitable). Always verify with site investigation data.
Traffic Loading
Subgrade & Layer Properties
Cumulative ESA
mESA
Design CBR
%
Structural Number (SN)
Required Subbase
mm
Required Surfacing
mm
Total Pavement Depth
mm
Reference Depths (HD 26/06): Pedestrian (50-75mm surface + 100mm subbase). Light vehicles (80mm AC + 150mm subbase for CBR 5%). Fire appliance (BS 9999): min 200mm concrete or 170mm AC + 250mm subbase.
Vehicle & Wheel Parameters
Stress Distribution Depth
Wheel Load (dynamic)
kN
Tyre Contact Area
cm²
Tyre Contact Radius
mm
Vertical Stress (Surface)
kPa
Vertical Stress (Depth)
kPa
Stress Attenuation
%
Horiz/Tensile Stress
kPa
Influence Zone (10%)
mm
Surfacing Subbase Subgrade Tyre Contact — kPa (surface) — kPa at depth z=—mm
Vertical stress calculated using Boussinesq (1885) theory for a uniformly loaded circular area. Valid for homogeneous, elastic, semi-infinite soil half-space. Actual distribution is modified by layered pavement stiffness.
Site & Traffic Parameters
Surface Layer Thickness
mm
Req. Reservoir Depth
mm
Total Construction Depth
mm
Stormwater Storage Vol
Peak Inflow Rate
L/s
Infiltration Rate (to ground)
L/s
Overflow Discharge Rate
L/s
Runoff Reduction
%
CIRIA C753 Guide: Min surface infiltration rate is 100 mm/hr for block, 1,000 mm/hr for porous asphalt. Sub-base typically uses Type 3 open-graded aggregate (35% voids). Geotextile needed if CBR <5%.
Tree Specification
Paving Over Root Zone
RPA Radius
m
Total RPA Area
SRZ Radius
m
Encroachment Area
Unpaved RPA
%
RPA Root Protection Area
BS 5837:2012 Guidelines: Max encroachment on RPA is 20% for Cat B trees, 5% for Cat A. Any works within RPA require an Arboricultural Method Statement (AMS). Permeable paving in RPA requires no-dig/vacuum excavation.
Design Vehicle & Route
Min. Width Required
m
Min. Vertical Clearance
m
Max Acceptable Gradient
%
Turning Circle Required
m (dia)
Overall Compliance
RequirementRequiredAvailableStatus
UK Fire Access Standards (BS 9999): Fire pump needs 3.7m width, 3.7m height, max 15% gradient, 16.8m turning circle. All fire routes must be verified by local Fire and Rescue Service.