# Casa Sobreposta R05 — 200 km/h wind screening

2 October 2026. **No verified 200 km/h capacity.** This calculation estimates load demand and screens isolated members. It is not a full structural analysis, wind tunnel test, CFD study or construction design.

## Input and formulas

200 km/h = 55.55556 m/s, assumed gust at building height. Air density = 1.225 kg/m³. Dynamic pressure q = ½ρV² = **1.890 kPa**. If 200 km/h instead denotes basic/mean speed, this treatment is not applicable without the appropriate exposure and gust treatment.

Net horizontal coefficients 0.8, 1.3 and 1.8 are illustrative sensitivities, not verified code coefficients. Member coefficient 1.1 is a separate assumed windward plus internal pressure case. No regional wind mapping or PDM research was repeated.

Upper greenhouse bounding silhouette: 32.00 × 4.725 m = 151.21 m². Roof maximum is 7.965 m above the house floor, including the raised vent canopy. Broadside force F = q C A. Overturning about podium = F × (5.643 m). This bounding rectangle includes the curved roof silhouette; true roof pressures need separate analysis.

| Assumed coefficient | Pressure kPa | Greenhouse side force kN | Moment at podium kNm | Roof uplift sensitivity kN |
|---|---:|---:|---:|---:|
| 0.8 | 1.512 | 228.7 | 1290.3 | 382.3 |
| 1.3 | 2.458 | 371.6 | 2096.8 | 621.3 |
| 1.8 | 3.403 | 514.5 | 2903.2 | 860.2 |

At C = 1.3, the greenhouse-only load is **372 kN** (about 37.9 tonnes-force). The full above-podium rectangular envelope gives 630 kN and 2520 kNm. These exclude any extra independent force on the west pergola. Side screens overlapping the greenhouse silhouette must not simply be counted twice.

Roof uplift of 621 kN is a separate sensitivity on 252.8 m² of plan area, before dead-weight resistance; it is not the horizontal force and does not supply bolt sizing. The 23.925 m² of shown deployed patio fabric alone gives 58.8 kN in the same assumed uplift-pressure case. No credit is taken for plants as a windbreak. Wet vegetation, supporting wires and planters also need their own load cases.

## Isolated member screens

E = 210 GPa and fy = 235 MPa assumed, not certified. IPE240 model dimensions b=120, h=240, tw=6.2, tf=9.8 mm give Istrong=3.6709673e-05 m⁴, Iweak=2.8267773e-06 m⁴, ignoring fillets. The facade's nominal 35 mm member is represented as a solid square, which is stiffer than a hollow section of the same outer size.

Cantilever: M = wL²/2, δ = wL⁴/(8EI). Simply supported: M = wL²/8, δ = 5wL⁴/(384EI). w = q C × tributary width; stress = M/Z. Stress/fy is an elastic yield screen, not a design utilisation or a buckling check.

| Member and idealisation | L m | Tributary m | M kNm | Stress MPa | Stress/fy | Linear δ mm |
|---|---:|---:|---:|---:|---:|---:|
| Greenhouse upper IPE240 / strong axis (cantilever) | 2.98 | 4.00 | 36.93 | 121 | 0.51 | 10.6 |
| Pergola full-height IPE240 / strong axis (cantilever) | 6.26 | 3.00 | 144.46 | 472 | 2.01 | 183.6* |
| Pergola full-height IPE240 / weak-axis sensitivity (cantilever) | 6.26 | 3.00 | 144.46 | 3066 | 13.05 | 2384.1* |
| Nominal solid 35 mm facade mullion (simply_supported) | 2.48 | 2.00 | 3.20 | 447 | 1.90 | 78.0* |

*Beyond assumed first yield: the quoted elastic displacement is not a credible actual deflection. The unrestrained full-height pergola-column and nominal facade-mullion idealisations exceed assumed yield. This is a reason to redesign/verify the load path and members, not a prediction that the real assembled structure fails at a particular wind speed. The upper IPE screen alone cannot establish safety.

The full-height pergola check assigns a 3 m wide dense planting screen to one 6.26 m fixed-base column. The strong/weak-axis results expose sensitivity to lateral restraint and section orientation. The actual roof ties and knee braces are not treated as verified restraints. The 35 mm facade mullion is assumed simply supported over its 2.48 m clear panel height with 2 m tributary width; actual glass/frame load sharing and fixings need design.

## Required structural resolution

Verify the wind definition, exposure and pressure cases; model the whole frame in both directions with realistic joints and diaphragms; define bracing through to the concrete; design glazing, clips, vents, tensile ties, base plates, anchors and foundations for uplift and overturning; check steel stability and combined loads. The current 35 mm greenhouse members are representation assumptions and should not become a fabrication specification.

Numerical checks: independent integration of the assumed pressure rectangle confirms global force/moment. A 20-element elastic beam solution checks the closed-form cantilever and simply supported results and reaction equilibrium. These checks verify the arithmetic, not the building.