Monroe Keys Boat Storage Building Wind Design

Under ASCE 7-22 Section 26.2, a building is classified as partially enclosed when the total area of openings in any wall exceeds both 4 square feet AND 1% of that wall's gross area, AND exceeds the aggregate open area of all other surfaces by more than 10%. Boat storage buildings with large roll-up doors almost always trigger this classification. This increases the internal pressure coefficient (GCpi) from +/-0.18 (enclosed) to +/-0.55 (partially enclosed), dramatically increasing net design pressures on roof systems, wall cladding, and all structural connections by 40-80% depending on component location.

Clear spans of 40-80 feet are common in boat storage to accommodate vessel maneuvering, forklift aisles, and rack storage systems. Without intermediate columns, all wind loads must transfer through the building's perimeter walls and end walls to the foundation. This requires heavier rigid frame designs with moment-resisting beam-to-column connections, deeper foundation embedments to resist overturning moments, and more robust diaphragm action in the roof system. In Monroe County's extreme wind zone, clear span buildings typically require PE-stamped structural calculations demonstrating complete load path continuity from roof deck to foundation anchor bolts.

Monroe County's marine environment creates severe corrosion conditions that can degrade structural capacity over time. ASCE 7-22 Section 4.3 requires consideration of environmental conditions affecting structural performance. For boat storage, this means specifying hot-dip galvanized connections (minimum G185 coating), 316 stainless steel fasteners and anchor bolts, marine-grade aluminum or properly coated steel framing, enhanced coating specifications with minimum 3-5 mil DFT, and shorter inspection intervals documented in building maintenance plans. Structural connections should be designed assuming 15-25% section loss over the building's design life.

Dry stack boat storage racks create additional wind loads that must be transferred to the building's main wind force resisting system. Per ASCE 7-22 Chapter 29 (Other Structures and Building Appurtenances), rack systems are analyzed using the projected area method with appropriate drag coefficients for the stored boats. Each boat tier creates drag forces based on its height above ground and the velocity pressure at that elevation. The rack-to-building connections must resist these lateral forces plus uplift from partial vacuum effects during hurricane passage. Typical multi-tier systems add 15-25 psf equivalent load to the building's MWFRS analysis.

Large door openings fundamentally change how wind interacts with a building. Under ASCE 7-22, when doors are assumed open during a design wind event (the conservative assumption for partially enclosed classification), wind enters the building and pressurizes the interior. The internal pressure coefficient jumps from +/-0.18 (enclosed) to +/-0.55 (partially enclosed) - effectively tripling the internal pressure contribution. For a 30-foot wide boat door on a 100-foot long building, this opening factor increases roof uplift pressures by approximately 39-64% and wall outward pressures by 40-50% compared to an enclosed building with the same geometry.