Seagrass Beach – Windstorm Design
IBHS Gold Standard Fortified Homes
The Fortified Disaster Resistant High-end Buildings in Galveston are designed for IBHS Gold Standard Certification.
These TDI compliant buildings are Sea facing in the VE-Zone and subjected to high wind speeds. Also, the Base Flood Elevation (BFE) is about 6 ft above the grade level. The structure is subjected to extensive wave action at 100-yr flood events.
The structural frame of the building is founded on 12 in x 12 in Southern Pine wood pylons at 14 ft O.C. The piles were driven to a depth of 18 ft below grade level. Anthony Power Beams were used to build the base for the 2nd level, which is kept above the high wave action, with a 24 in freeboard. Break-away walls were designed for the ground level, with nailing schedule to collapse under the wave action. The structure is designed to Hurricane winds of 160mph ultimate, per ASCE 10 criteria.
The building had 30 ft clear spans in the second level, creating challenges for placing shear walls. Per the owner’s requirement to limit floor deflections, the structure was designed with wooden I-Beams for the second floor, and trusses for the third level. Simpson Storngwalls* were placed to enhance shear capabilities to safely transfer hurricane wind loads. Extensive search and vetting were done for procuring all fixtures, doors and windows for this building. The structural design was performed to IBHS Gold standard, and TDI’s windstorm standards. Extensive metal strapping, shear load transfer from shear walls, and diaphragm action were built into the design.
Windstorm inspections were performed in compliance to the TDI and IBHS requirements.