47.5 MB - The Whole Building Design Guide

Table 2-3: Checklist for Building Vulnerability of Flood-Prone Critical Facilities (continued)StructuralVulnerability Sections Guidance ObservationsWhat is the constructiontype and the foundationtype and what is the loadbearing capacity?Has the foundationbeen designed toresist hydrostatic andhydrodynamic flood loads?If the building has belowgradeareas, are thelower floor slabs subject tocracking and uplift?If the building is elevatedon a crawlspace an openfoundation, are there anyenclosed areas?For an existing buildingwith high value uses belowthe flood elevation, isthe building suitable forelevation-in-place or canit be relocated to higherground?If siting in a floodplain is unavoidable, newfacilities are to be designed to account for allloads and load combinations, including floodloads.Building spaces below the design flood levelcan be dry floodproofed, although it must berecognized that higher flood levels will overtopthe protection measures and may result insevere damage. Dry floodproofing creates largeunbalanced forces that can jeopardize wallsand foundations that are not designed to resistthe hydrostatic and hydrodynamic loads.New buildings may have enclosures belowthe flood elevation provided the use of theenclosures is limited (crawlspace, parking,building access, limited storage). In addition,the enclosures must have flood openings toautomatically allow for inflow and outflow offloodwaters to minimize differential hydrostaticpressure.Existing buildings that are elevated and haveenclosures below the flood elevation can beretrofit with flood openings.Elevating a building provides better protectionthan dry floodproofing. Depending on the typeand soundness of the foundation, even largebuildings can be elevated on a new foundationor moved to a site outside of the floodplain.MAKING CRITICAL FACILITIES SAFE FROM Flooding2-99