The problem
Solar carports combine shade, generation and charging, and are increasingly built at offices, malls and campuses. They are outdoor steel structures that must carry panel weight and strong wind uplift, sometimes with charger and cable loads. A student design teaches structural load paths, codes and connection detailing on a real EV infrastructure product.
Objectives
- Lay out an example two-bay carport with panel area, clearance and charger positions.
- Model columns, rafters and purlins as Weldments with standard steel profiles.
- Apply dead, live and wind loads based on the relevant Indian standards and combine them.
- Analyse with beam elements, check stresses and deflections, and confirm with hand calculations.
- Detail base plate and rafter connections and produce cut lists and drawings.
What you need
Tools and toolboxes
- SOLIDWORKS Weldments — Structural Member feature with standard profiles, trim and extend, gussets, end caps and a cut list.
- SOLIDWORKS Simulation (Static) — Beam element study with joint groups, fixed supports, distributed loads and load combinations.
- SOLIDWORKS Simulation (Frequency or Buckling) — Check natural frequency and buckling of slender members.
- SOLIDWORKS Drawings — Fabrication drawings with weld symbols, cut list tables and base plate details.
- Excel — Load calculations and hand checks of beam bending and column buckling.
Software
- SOLIDWORKS 2023 or later
- SOLIDWORKS Simulation
- Excel
Extra parts and data
- PV panel and charger datasheets — Panel size and mass and charger mass and mounting define the dead loads and layout.
Key concepts
- Wind uplift
- Wind flowing under a canopy can lift it. Canopies are often governed by uplift rather than downward load, which reverses stresses and loads the foundations in tension.
- Load combinations
- Design checks combine dead, live and wind loads with factors set by the relevant code, so the worst realistic case is checked.
- Beam elements
- Structural members modelled as lines with section properties. They give fast, accurate results for frames, while solid meshes are used for local details.
- Serviceability
- Limits on deflection and vibration so the structure looks and feels sound and panels are not damaged, separate from strength.
Step-by-step guide
- 1
Lay out the carport
Plan an example two-bay carport: bays 2.5 m wide by 5 m deep, a clear height of about 2.5 m at the low side, a single-slope canopy at a tilt suited to the latitude, and two wall-box chargers on the columns. Sketch a side and plan view with a car and person for scale. Calculate canopy area and how many PV panels fit using a panel datasheet.
Checkpoint: Layout sketches with dimensions, panel count and charger positions.
- 2
Model the structure
Create a 3D sketch or layout sketches for column, rafter and purlin centre lines. Use the Structural Member feature with standard profiles, for example square hollow sections for columns and C-sections for purlins, chosen from the profile library or added to it. Use Trim/Extend at joints and add gussets and end caps. Check the cut list lists every member with length and profile.
Checkpoint: A weldment with a complete cut list and correct member lengths, rebuilding when the bay width changes.
- 3
Calculate loads
Compute dead load from panels, purlins and fixings, and charger mass on the columns. Take a maintenance live load on the roof as in IS 875 Part 2. Compute wind pressure from IS 875 Part 3 for an example site, considering both downward pressure and uplift on a free-standing canopy. State that values must be checked against the current standard. Tabulate all loads per square metre and per member.
Checkpoint: A load table with dead, live and wind loads, both pressure and uplift, and their sources.
- 4
Hand-size members
Before simulating, size the purlins as simply supported beams under the line load from tributary area, checking bending stress and deflection against a span-based limit. Size rafters similarly with purlin point loads. Check columns for combined axial load and bending, and for buckling with an effective length that reflects the base fixity. This gives expected numbers to compare with the simulation.
Checkpoint: Hand calculations for purlin, rafter and column with stress and deflection values.
- 5
Set up the beam study
Create a static study; SOLIDWORKS treats structural members as beams. Edit joint groups and check the joint markers at each connection. Fix the column bases (or use pinned supports to test sensitivity). Apply distributed loads on purlins for dead, live and wind cases as separate studies or load cases, and gravity for self-weight. Assign a steel grade from the material library to every member, and check that the beam sections and orientations match the cut list profiles.
Checkpoint: The study meshes with all joints detected correctly and reactions sum to the applied load for the dead load case.
- 6
Run and combine load cases
Run each load case and combine them following the code's load combinations, either by separate studies with factored loads or with the Load Case Manager if your licence has it. Check maximum beam stresses (axial plus bending) against allowable values and deflections against serviceability limits. Note which case governs: often wind uplift for the rafters and columns. Plot the deformed shape for each governing case at an exaggerated scale, which helps catch loads applied in the wrong direction.
Checkpoint: A results table per combination with the governing case identified and all members within stress and deflection limits.
- 7
Compare with hand calculations
Compare simulation results for the purlin, rafter and column with your hand calculations. Differences should be explained by fixity, load distribution or member continuity. If they differ greatly, look for errors in joint groups, units or load direction. Run a buckling study on the most loaded column and compare the load factor with your hand check. Also refine the beam mesh once and confirm member stresses change very little, which shows the results are not mesh dependent.
Checkpoint: Simulation and hand values within a reasonable band, with differences explained, and buckling load factor above the target.
- 8
Check frequency and detail connections
Run a frequency study to make sure the first mode is not very low, which could make the canopy sway in wind. Then design the column base plate with anchor bolts and the rafter-to-column connection with a bolted end plate. Model one connection as a solid part and run a local static study with forces from the beam results to check plate bending and bolt loads.
Checkpoint: First natural frequency above a stated value and the base plate and bolt check with factor of safety above the target.
- 9
Drawings and report
Produce general arrangement drawings, member drawings from the cut list, base plate and connection details with weld symbols and bolt specifications, and a cut list table. Render the carport with cars and chargers. Write a report with layout, loads, hand calculations, simulation results, connection checks and limitations, stating that foundation design and final structural approval need a qualified structural engineer.
Checkpoint: A drawing set, renders and a report with clear limits of the student design.
Testing & validation
- Reactions balance applied loads in each case.
- Hand calculations and simulation agree within a stated band.
- All members pass stress and deflection checks for every combination.
- Buckling and frequency checks meet stated targets.
- Connections are checked with local studies.
Expected results
A two-bay solar carport weldment design with load calculations, beam element analysis under combined loads, hand checks, connection details and fabrication drawings, plus renders with chargers.
Take it further
- Compare a single-column cantilever design with a two-column design for steel mass.
- Add cable trays and charger mounting brackets with their own checks.
- Estimate annual PV generation for the canopy with a simple solar model.
Viva and review questions
Why is wind uplift often critical?
On an open canopy, wind can push up on the underside while suction acts on top, and the light dead load of panels does little to counter it. This reverses member stresses and puts the foundations in tension.
Why use beam elements?
They model slender frames accurately and quickly with section properties, so many load cases can be run. Local connections are then checked with solid models.
How did you check your results?
By confirming reactions balance applied loads and comparing member stresses and deflections with hand calculations for simply supported and cantilever cases.
Learn it at DIYguru
These DIYguru courses and programmes teach what this project needs.