Structure Plan & Profile Generator
Upload three geometric files: Horizontal coordinate alignment (csv), Vertical profile elevation PVI points (csv), and hydrology crossings layout (csv). This generator will automatically interpolate central alignments and calculate depths of cover, skew coordinates, and build SVG longitudinal sectional drawings on the fly.
Import Data Sources
Slab & Precision Math
Awaiting alignment and structure data
To begin calculations, upload the three CSV files (Horizontal, Vertical, Hydrology) in the left panel and click the "Compile" button.
Engineering Notice & Review Requirement:
Calculation generated by InfraDigital CAD based on the selected methodology and entered parameters. Project-specific engineering review and verification are required before final design, submission or construction use.
Structure Plan & Profile Generator Documentation
Technical specifications, mathematical formulas, and civil guidelines
1. Functional Purpose & Methodology
Designing road crossing drainage structures (pipe and reinforced concrete box culverts) requires synchronizing three independent data streams: horizontal centerline coordinates, vertical profile grade elevations, and stream catchment hydraulic invert schedules. The Structure Plan & Profile Generator automates this multi-dimensional geometric reconciliation.
It calculates culvert barrel lengths along skew angles, derives exact roadway crown and shoulder elevations at the crossing station, evaluates depth of earth cover over the culvert top slab, and renders interactive longitudinal cross-sections to verify clearance against minimum structural cover envelopes.
2. Practical Step-by-Step Instructions
- Upload Corridor Geometry: Upload the Horizontal Alignment CSV (Station, Easting, Northing), Vertical Profile CSV (Station, Elevation), and Culvert Inventory CSV.
- Configure Cross-Section Geometry: Set carriageway width (e.g., 7.0m), shoulder width (e.g., 1.5m to 2.0m), and normal crown cross-slope (-2.5%).
- Specify Structure Dimensions: Enter barrel opening dimensions (span × height for box culverts, or diameter ∅ for pipe culverts), wall/slab thicknesses (m), and skew angle (θ degrees from perpendicular).
- Review Interactive SVG Section: Inspect the live longitudinal profile showing roadway finished grade, subgrade level, culvert barrel, inlet/outlet headwalls, and stream bed invert levels.
- Export Submittal Schedule: Download the complete culvert geometric schedule in Excel with calculated inlet/outlet coordinates, invert elevations, and barrel lengths.
3. Mathematical Formulations & Variable Definitions
Geometric reconciliation applies linear interpolation and trigonometric skew formulas:
- Roadway Profile Elevation Interpolation (Z_road): At culvert crossing chainage S_c between profile stations S1 and S2:Z_road = Z1 + [ (S_c - S1) / (S2 - S1) ] × (Z2 - Z1)
- Skewed Barrel Length (L_barrel):L_barrel = W_embankment / cos(θ)Where W_embankment = total embankment width at culvert level (m), and θ = skew angle relative to road centerline perpendicular.
- Depth of Earth Cover (C): Vertical clearance between finished road surface and outer top slab/crown:C = Z_road - (Z_invert + H_internal + t_slab)Where Z_invert = culvert internal invert elevation, H_internal = inner barrel height, and t_slab = top-slab structural thickness.
- Culvert Longitudinal Slope (S_culv):S_culv = (Z_inlet - Z_outlet) / L_barrel
4. Minimum Structural Cover Requirements (ERA & AASHTO)
Minimum cover depths per ERA Drainage Design Manual 2013 and AASHTO LRFD Bridge Design Specifications:
| Structure Type | Minimum Cover under Pavement | Maximum Permissible Cover | Special Design Action if C < Min |
|---|---|---|---|
| Reinforced Concrete Box Culvert | 0.30 m (or 0.50m for heavy traffic) | 8.0 m - 12.0 m | Direct-traffic slab design required; top slab acts as pavement base |
| Corrugated Precast Concrete Pipe | 0.60 m (or 1.0 × ∅ in unpaved) | 6.0 m - 9.0 m | Class IV / Class V reinforced pipe or full concrete cradle surround |
| Corrugated Metal Pipe (CMP) | 0.30 m to 0.60 m | 5.0 m - 10.0 m | Structural plate thickness increase or select granular backfill |
5. Output Interpretation & Quality Control
Warning indicators to review in the compiled plan-profile results:
- Shallow Cover Warning: If C < 0.30m, the top slab encroaches into the pavement structural layers. The road profile must be raised or a specialized deck slab detailed.
- Negative Culvert Slope: Culvert inverts sloping backward (Z_outlet > Z_inlet) will cause silt accumulation and complete structure failure.
- Excessive Skew: Skew angles exceeding 45° significantly lengthen the barrel and increase costs; consider channel realignment where feasible.
6. Related Technical Guides & Workflow Integration
Read our guide on Drafting Culvert Plan & Profile for step-by-step CAD production workflows. For hydraulic sizing of these culverts, use the Culvert & Ditch Hydraulic Sizer.