47.5 MB - The Whole Building Design Guide

Figure 2-30:Flood hazard zones incoastal areasField observations and laboratory researchhave determined that floodingAlthough the NFIP regulations and the modelbuilding codes allow dry floodproofing ofwith breaking waves between 1.5 and 3nonresidential buildings in flood hazard areasfeet high produces more damage thanwhere waves are predicted to be betweenflooding of similar depths without waves.1.5 and 3 feet during the base flood (calledTherefore, ASCE 24 specifically requiresCoastal A Zones), designers are cautioned toapplication of the NFIP’s V Zone designfully consider the additional forces associatedrequirements in Coastal A Zones. Sectionwith wave impacts, which may make dry2.3.2.1 addresses elevation requirementsfloodproofing a less feasible alternative.and foundation types, and Section 2.3.2.2addresses flood-resistant materials, usedin V Zones and Coastal A Zones. Thedesigners are advised to pay special attention to two additionalconsiderations:m Debris loads may be significant in Coastal A Zones landward ofV Zones where damaged buildings, piers, and boardwalks canproduce battering debris. Foundations designed to account fordebris loads will minimize damage.m Especially in high wind regions, designers must pay specialattention to the entire roof-to-foundation load path whendesigning and specifying connections. If designed to meetV Zone requirements, designs for buildings in Coastal AZones will account for simultaneous wind and flood forces.Corrosion-resistant connections are especially important forthe long-term integrity of the structure.MAKING CRITICAL FACILITIES SAFE FROM Flooding2-71