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<br />I <br /> <br />~ <br />( <br />l <br />( <br />\ <br />I <br />\ <br />\ <br />\ <br />~ <br />( <br />I <br />! <br /> <br />. Debris - where debris accompanies flood flows support members must be protected and <br />designed to withstand associated impact forces. <br /> <br />. Aesthetics - architectural considerations frequently determine the type, height and <br />arrangement of support members. <br /> <br />Earth fill and support members are applicable to a wide range of structures and flood hazard <br />conditions. They may be used to elevate structures to most any height although local site <br />conditions and architectural considerations usually impose practical-limits. They may be used <br />separately or together depending upon the need. While they both achieve the same purpose, <br />that of elevating a structure to a less flood susceptible level, earth fill can also be used to elevate <br />other damageable property - utilities, roads, bridges, storage areas - at the same time that <br />structures are elevated. It has the additionai advantage of reducing the susceptibility to scour <br />and debris by keeping flood waters away from the structure. <br /> <br />Costs <br />The cost of elevating a new structure is measured as the difference between constructing a <br />structure on a low foundation and the cost of constructing it elevated. If the same structure is to <br />be built, but in an elevated position, the principal cost items are the fill and/or support <br />members, access ramps and stairways, and additional duct work, wiring and plumbing. <br />Frequently, however, the fact that the structure will be located in a flood hazard area results in <br />the selection of a structure which is architecturally and functionally compatible with the hazard <br />and not just a flood-free-site structure elevated. In this situation the cost of flood protection <br />should be estimated using the structure types likely to be used with and without the hazard. <br />Cost is also a function of height. Elevating to greater heights will normally increase labor and <br />materiai costs. <br /> <br />Cost estimates using nationwide data show increased cost of elevating structures range from <br />$1.10 to $2.32 per square foot of structure depending upon the type of foundation (Reference 1, <br />Table 4-1). Slab-on-grade to concrete pier yielded the maximum increased cost and crawl space <br />to wood pile the least. The height raised ranged from 6'0" to 7''1' depending upon the type of <br />foundation. For purposes of this study, minimum costs for elevating a 1,600 square foot, $30,000 <br />structure three feet and five feet were estimated to be $1.10 and $1.50 respectively. Table 9-1 <br />shows the approximate annual cost as a percentage of structure value. <br /> <br />64 <br />