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    RECOMMENDED RESIDENTIAL CONSTRUCTION FOR THE GULF COAST 3-

    3.FoundationDesign LoadsThis chapter provides guidance on how to determine the magnitude

    of the loads placed on a building by a particular natural hazard event

    or a combination of events. The methods presented are intended toserve as the basis of a methodology for applying the calculated loads

    to the building during the design process.

    The process or determining site-specic loads rom natural hazards begins with identiying the

    building codes or engineering standards in place or the selected site (e.g., the InternationalBuilding Code 2003 (IBC 2003) or ASCE 7-02, Minimum Design Loads for Buildings and OtherStructures), i model building codes and other building standards do not provide load determi-nation and design guidance or each o the hazards identied. In such instances, supplementalguidance such as FEMA 55 should be sought, the loads imposed by each o the identied haz-ards should be calculated, and the load combinations appropriate or the building site shouldbe determined. The load combinations used in this manual are those specied by ASCE 7-02,the standard reerenced by the IBC 2003. Either Allowable Stress Design (ASD) or Strength

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    Design methods can be used to design a building. For this manual, all o the calculations, analy-ses, and load combinations presented are based on ASD. The use o Strength Design methodswill require the designer to modiy the design values presented in this manual to accommodateStrength Design concepts. Assumptions utilized in this document can be ound in AppendixC.

    3.1 WindLoads

    Wind loads on a building structure are calculated using the methodology presentedin ASCE 7-02, Minimum Design Loads for Buildings and Other Structures. This documentis the wind standard reerenced by the 2003 editions o the IBC and IRC. Equations

    used to calculate wind loads are presented in Appendix D.

    The most important variable in calculating wind load is the design wind speed. Design windspeed can be obtained rom the local building ocial or the ASCE 7-02 wind speed map (seeFigure 3-). The speeds shown in this gure are 3-second gust speeds or Exposure CategoryC at a 33-oot (0-meter) height. ASCE 7-02 includes scaling actors or other exposures andheights.

    ASCE 7-02 species wind loads or structural components known as a Main Wind Force Re-sisting System (MWFRS). The oundation designs developed or this manual are based onMWFRS pressures calculated or Exposure Category C, the category with the highest antici-pated wind loads or land-based structures.

    ASCE 7-02 also species wind loads or components and cladding (C&C). Components andcladding are considered part o the building envelope, and ASCE 7-02 requires C&C to be de-signed to resist higher wind pressures than MWFRS.

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    Figure3-1. Windspeed(inmph)intheU.S.GulCoastarea

    Source: ASce 7-02

    3.2FloodLoads

    This manual develops in more detail food load calculations and incorporates the methodol-ogy presented in ASCE 7-02. Although wind loads can directly aect a structure and dictatethe actual oundation design, the oundation is more aected by food loads. ASCE 24 dis-

    cusses foodproo construction. Loads developed in ASCE 24 come directly rom ASCE 7-02,which is what the designs presented herein are based upon.

    The eects o food loads on buildings can be exacerbated by storm-induced erosion and lo-calized scour, and by long-term erosion. Erosion and scour lower the ground surace aroundoundation members and can cause the loss o load-bearing capacity and resistance to lateraland uplit loads. Erosion and scour also increase food depths and, thereore, increase depthdependent food loads.

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    Figure3-2.

    Parametersthat

    determineorare

    aectedbyooddepth

    Source: COastal

    COnstruCtiOn manual

    (FeMA 55)

    3.2.1 DesignFloodandDesignFloodElevation(DFE)

    The design food is dened by ASCE 7-02 as the greater o the ollowing two food events:

    . Base food, aecting those areas identied as SFHAs on the communitys FIRM, or

    2. The food corresponding to the area designated as a food hazard area on a communitysfood hazard map or otherwise legally designated.

    The DFE is dened as the elevation o the design food, including wave height and reeboard,relative to the datum specied on a communitys food hazard map. Figure 3-2 shows the param-eters that determine or are aected by food depth.

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    3.2.2 DesignStillwaterFloodDepth(ds)

    Design stillwater food depth (ds) is the vertical distance between the eroded ground elevationand the stillwater food elevation associated with the design food. Determining the maximumdesign stillwater food depth over the lie o a building is the single most important food load

    calculation that will be made; nearly all other coastal food load parameters or calculations (e.g.,hydrostatic load, design food velocity, hydrodynamic load, design wave height, DFE, debris im-pact load, local scour depth) depend directly or indirectly on the design stillwater food depth.The design stillwater food depth (ds) is dened as

    ds = Esw GS

    Where

    ds = Design stillwater food depth (t)

    Esw

    = Design stillwater food elevation (t) above the datum (e.g., National Geodetic Ver-tical Datum [NGVD], North American Vertical Datum [NAVD]), including wave setupeects

    GS = Lowest eroded ground elevation above datum (t), adjacent to building, includingthe eects o localized sour around pilings

    GS is not the lowest existing pre-food ground surace; it is the lowest ground surace that willresult rom long-term erosion and the amount o erosion expected to occur during a designfood, excluding local scour eects. The process or determining GS is described in Chapter 7o FEMA 55.

    Values or Esw are not shown on a FIRM, but they are given in the Flood Insurance Study (FIS)report, which is produced in conjunction with the FIRM or a community. FIS reports are usu-ally available rom community ocials, rom NFIP State Coordinating Agencies, and on the webat the FEMA Map Service Center (http://store.msc.ema.gov). Some states have FIS reportsavailable on their individual web sites.

    3.2.3 DesignWaveHeight(Hb)

    The design wave height at a coastal building site will be one o the most important design pa-rameters. Thereore, unless detailed analysis shows that natural or manmade obstructions will

    protect the site during a design event, wave heights at a site will be calculated rom Equation 5-2o ASCE 7-02 as the heights o depth-limited breaking waves (Hb), which are equivalent to 0.78times the design stillwater food depth:

    Hb = 0.78ds

    Note: 70 percent o the breaking wave height (0.7Hb) lies above the stillwater food level.

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    3.2.4 DesignFloodVelocity(V)

    Estimating design food velocities in coastal food hazard areas is subject to considerable un-certainty. Little reliable historical inormation exists concerning the velocity o foodwatersduring coastal food events. The direction and velocity o foodwaters can vary signicantly

    throughout a coastal food event, approaching a site rom one direction during the beginningo the food event beore shiting to another (or several directions). Floodwaters can inundatesome low-lying coastal sites rom both the ront (e.g., ocean) and the back (e.g., bay, sound,river). In a similar manner, fow velocities can vary rom close to zero to high velocities duringa single food event. For these reasons, food velocities should be estimated conservatively byassuming that foodwaters can approach rom the most critical direction and that fow veloci-ties can be high.

    For design purposes, the Commentaryo ASCE7-02 suggested a range o food velocities rom:

    V = ds t (expected lower bound)

    to

    V = (gds)0.5 (expected upper bound)

    Where

    ds = Design stillwater food depth

    t = Time ( second)

    g = Gravitational constant (32.2 t/sec2)

    Factors that should be considered beore selecting the upper- or lower-bound food velocity ordesign include:

    n Flood zone

    n Topography and slope

    n Distance rom the source o fooding

    n Proximity to other buildings or obstructions

    The upper bound should be taken as the design food velocity i the building site is near the

    food source, in a V Zone, in an AO Zone adjacent to a V Zone, in an A Zone subject to veloc-ity fow and wave action, steeply sloping, or adjacent to other buildings or obstructions that willconne foodwaters and accelerate food velocities. The lower bound is a more appropriate de-sign food velocity i the site is distant rom the food source, in an A Zone, fat or gently sloping,or unaected by other buildings or obstructions.

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    3.3 HydrostaticLoads

    Hydrostatic loads occur when standing or slowly moving water comes into contact with abuilding or building component. These loads can act laterally (pressure) or vertically(buoyancy).

    Lateral hydrostatic orces are generally not sucient to cause defection or displacement oa building or building component unless there is a substantial dierence in water elevationon opposite sides o the building or component; thereore, the NFIP requires that foodwateropenings be provided in vertical walls that orm an enclosed space below the BFE or a buildingin an A Zone.

    Lateral hydrostatic orce is calculated by the ollowing:

    stat = ds2

    Where

    stat = Hydrostatic orce per unit width (lb/t) resulting rom fooding against verticalelement

    = Specic weight o water (2.4 lb/t3 or reshwater and 4 lb/t3 or saltwater)

    Vertical hydrostatic orces during design food conditions are not generally a concern or prop-erly constructed and elevated coastal buildings. Buoyant or fotation orces on a building can beo concern i the actual stillwater food depth exceeds the design stillwater food depth.

    Vertical (buoyancy) hydrostatic orce is calculated by the ollowing:

    FBuoy= (Vol)

    Where

    FBuoy= vertical hydrostatic orce (lb) resulting rom the displacement o a given volume ofoodwater

    Vol = volume o foodwater displaced by a submerged object (t3) = displaced area x depth

    o fooding

    Buoyant orce acting on an object must be resisted by the weight o the object and any other op-posing orce (e.g., anchorage orces) resisting fotation. In the case o a building, the live loadon foors should not be counted on to resist buoyant orces.

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    3.4 WaveLoads

    Calculating wave loads requires inormation about expected wave heights. For the purpos-es o this manual, the calculations will be limited by water depths at the site o interest.Wave orces can be separated into our categories:

    n Non-breaking waves (can usually be computed as hydrostatic orces against walls and hydro-dynamic orces against piles)

    n Breaking waves (short duration but large magnitude orces against walls and piles)

    n Broken waves (similar to hydrodynamic orces caused by fowing or surging water)

    n Uplit (oten caused by wave runup, defection, or peaking against the underside o hori-zontal suraces)

    O these our categories, the orces rom breaking waves are the largest and produce the most

    severe loads. Thereore, it is strongly recommended that the breaking wave load be used as thedesign wave load.

    Two breaking wave loading conditions are o interest in residential construction: waves breakingon small-diameter vertical elements below the DFE (e.g., piles, columns in the oundation o abuilding in a V Zone) and waves breaking against vertical walls below the DFE (e.g., solid oun-dation walls in A Zones, breakaway walls in V Zones).

    3.4.1 BreakingWaveLoadsonVerticalPiles

    The breaking wave load (Fbrkp) on a pile can be assumed to act at the stillwater food level and

    is calculated by Equation 5-4 rom ASCE 7-02:

    Fbrkp = (/2)CDDHb2

    Where

    Fbrkp = Net wave orce (lb)

    CD = Coecient o drag or breaking waves = .75 or round piles or column, and 2.25 orsquare piles or columns

    = Specic weight o water (lb/t3)

    D = Pile or column diameter (t) or circular section. For a square pile or column, .4times the width o the pile or column (t).

    Hb = Breaking wave height (t)

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    3.4.2 BreakingWaveLoadsonVerticalWalls

    The net orce resulting rom a normally incident breaking wave (depth limited in size, withHb = 0.78ds) acting on a rigid vertical wall, can be calculated by Equation 5- rom ASCE 7-02:

    Fbrkw = .Cpds2 + 2.4ds2

    Where

    Fbrkw = net breaking wave orce per unit length o structure (lb/t) acting near the stillwaterfood elevation

    Cp = Dynamic pressure coecient (. < Cp < 3.5) (see Table 3-)

    Table3-1.BuildingCategoryandCorrespondingDynamicPressureCoeicient(Cp)

    BuildingCategory Cp

    I Bildings and th stts that psnt a lw

    hazad t hman lif in th vnt f a fail1.6

    II Bildings nt in catgy I, III, and IV 2.8

    III Bildings and th stts that psnt a sbstantialhazad t hman lif in th vnt f a fail

    3.2

    IV Bildings and th stts dsignatd as ssntial failitis 3.5

    Source: ASce 7-02

    = Specic weight o water (lb/t3)

    ds = Design stillwater food depth (t) at base o building where the wave breaks

    This ormula assumes the ollowing:

    n The vertical wall causes a refected or standing wave against the seaward side o the wall withthe crest o the wave, reaching a height o .2ds above the design stillwater food elevation,and

    n The space behind the vertical wall is dry, with no fuid balancing the static component othe wave orce on the outside o the wall (see Figure 3-3).

    I ree-standing water exists behind the wall (see Figure 3-4), a portion o the hydrostatic com-ponent o the wave pressure and orce disappears and the net orce can be computed usingEquation 5-7 rom ASCE 7-02:

    Fbrkw = .Cpds2 + .ds

    2

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    Figure3-4.

    Normallyincident

    breakingwavepressures

    againstaverticalwall

    (stillwaterlevelequalon

    bothsidesowall)

    Source: ASce 7-02

    Figure3-3.

    Normallyincident

    breakingwave

    pressuresagainsta

    verticalwall(space

    behindverticalwallis

    dry)

    Source: ASce 7-02

    Post-storm damage inspections show that breaking wave loads have destroyed virtually all wood-rame or unreinorced masonry walls below the wave crest elevation; only highly engineered,massive structural elements are capable o withstanding breaking wave loads. Damaging wavepressures and loads can be generated by waves much lower than the 3-oot wave currently usedby FEMA to distinguish between A Zones and V Zones.

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    3.5 HydrodynamicLoads

    Water fowing around a building (or a structural element or other object) imposes ad-ditional loads on the building. The loads (which are a unction o fow velocity andstructural geometry) include rontal impact on the upstream ace, drag along the sides,

    and suction on the downstream side. This manual assumes that the velocity o the foodwaters isconstant (i.e., steady state fow).

    One o the most dicult steps in quantiying loads imposed by moving water is determining theexpected food velocity. Reer to Section 3.2.4 or guidance concerning design food velocities.

    The ollowing equation rom FEMA 55 can be used to calculate the hydrodynamic load romfows with velocity greater than 0 t/sec:

    Fdyn = CdV2A

    Where

    Fdyn = Hydrodynamic orce (lb) acting at the stillwater mid-depth (halway between thestillwater elevation and the eroded ground surace)

    Cd = Drag coecient (recommended values are 2.0 or square or rectangular piles and.2 or round piles)

    = Mass density o fuid (.4 slugs/t3 or reshwater and . slugs/t3 or saltwater)

    V = Velocity o water (t/sec)

    A = Surace area o obstruction normal to fow (t2)

    Note that the use o this ormula will provide the total orce against a building o a given im-pacted surace area (A). Dividing the total orce by either length or width would yield a orceper unit length; dividing by A would yield a orce per unit area.

    The drag coecient used in the previously stated equations is a unction o the shape o theobject around which fow is directed. I the object is something other than a round, square, orrectangular pile, the drag coecient can be determined using Table 3-2.

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    Table3-2.DragCoefcientBasedonWidthtoDepthRatio

    WidthtoDepthRatio

    (w/dsorw/h)DragCoeicient(Cd)

    1 t 12 1.25

    13 t 20 1.30

    21 t 32 1.40

    33 t 40 1.50

    41 t 80 1.75

    81 t 120 1.80

    >120 2.00

    Nt: h fs t th hight f an bjt mpltly immsd in wat.

    Source: FeMA 55

    Flow around a building or building component will also create fow-perpendicular orces (litorces). I the building component is rigid, lit orces can be assumed to be small. But i thebuilding component is not rigid, lit orces can be greater than drag orces. The ormula orlit orce is similar to the ormula or hydrodynamic orce except that the drag coecient(Cd) is replaced with the lit coecient (C l). For the purposes o this manual, the ounda-tions o coastal residential buildings can be considered rigid, and hydrodynamic lit orcescan thereore be ignored.

    3.6 DebrisImpactLoads

    Debris or impact loads are imposed on a building by objects carried by moving water. Themagnitude o these loads is very dicult to predict, yet some reasonable allowance mustbe made or them. The loads are infuenced by where the building is located in the poten-

    tial debris stream:

    n Immediately adjacent to or downstream rom another building

    n Downstream rom large fotable objects (e.g., exposed or minimally covered storage tanks)

    n Among closely spaced buildings

    The ollowing equation to calculate the magnitude o impact load is provided in the Commentaryo ASCE 7-02:

    Fi = (WVCiCoCDCBRmax) (2gt)

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    Where

    Fi = Impact orce acting at the stillwater level (lb)

    = 3.4

    W = Weight o debris (lb), suggest using ,000 i no site-specic inormation is available

    V = Velocity o object (assume equal to velocity o water) (t/sec)

    Ci = Importance coecient (see Table C5.3 o ASCE 7-02)

    Co = Orientation coecient = 0.8

    CD = Depth coecient (see Table C5.5 and Figure C5-3 o ASCE 7-02)

    CB = Blockage coecient (see Table C5.5 and Figure 5-4 o ASCE 7-02)

    Rmax= Maximum response ratio or impulsive load (see Table C5. o ASCE 7-02)

    g = Gravitational constant (32.2 t/sec2)

    t = Duration o impact (sec)

    When the C coecients and Rmax are set to .0, the above equation reduces to

    Fi = (WV) (2gt)

    This equation is very similar to the equation provided in ASCE 7-8 and FEMA 55. The only di-erence is the /2 term, which results rom the hal-sine orm o the impulse load.

    The ollowing uncertainties must be quantied beore the impact o debris loading on thebuilding can be determined using the above equation:

    n Size, shape, and weight (W) o the waterborne object

    n Flood velocity (V)

    n Velocity o the object compared to the food velocity

    n Portion o the building that will be struck and most vulnerable to collapsing

    n Duration o the impact (t)

    Once foodborne debris impact loads have been quantied, decisions must be made on how toapply them to the oundation and how to design oundation elements to resist them. For open

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    oundations, the Coastal Construction Manual(FEMA 55) advises applying impact loading to acorner or critical column or piling concurrently with other food loads (see Coastal Construc-tion Manual, Table -). For closed oundations (which are not recommended in Coastal AZones and are not allowed in V Zones), the Coastal Construction Manualadvises that the design-er assume that one corner o the oundation will be destroyed by debris and recommends the

    oundation and the structure above be designed to contain redundancy to allow load redistribu-tion to prevent collapse or localized ailure. The ollowing should be considered in determiningdebris impact loads:

    Size, shape, and weight of the debris. It is recommended that, in the absence o inormationabout the nature o the potential debris, a weight o ,000 pounds be used or the debris weight(W). Objects o this weight could include portions o damaged buildings, utility poles, portionso previously embedded piles, and empty storage tanks.

    Debris velocity. Flood velocity can be approximated by one o the equations discussed in Sec-tion 3.2.4. For the calculation o debris loads, the velocity o the waterborne object is assumed to

    be the same as the food velocity. Note that, although this assumption may be accurate or smallobjects, it will overstate debris velocities or large objects (e.g., trees, logs, pier pilings). TheCommentaryo ASCE 7-02 provides guidance on estimating debris velocities or large debris.

    Portion of building to be struck. The object is assumed to be at or near the water suracelevel when it strikes the building. Thereore, theobject is assumed to strike the building at thestillwater food level.

    Duration of impact. Uncertainty about the dura-tion o impact(t) (the time rom initial impact,through the maximum defection caused by theimpact, to the time the object leaves) is the mostlikely cause o error in the calculation o debrisimpact loads. ASCE 7-02 showed that measuredimpact duration (rom initial impact to time omaximum orce) rom laboratory tests variedrom 0.0 to 0.05 second. The ASCE 7-02 recom-mended value or t is 0.03 second.

    3.7 LocalizedScour

    Waves and currents during coastal food conditions are capable o creating turbulencearound oundation elements and causing localized scour. Determining potentialscour is critical in designing coastal oundations to ensure that ailure during and

    ater fooding does not occur as a result o the loss in either bearing capacity or anchoringresistance around the posts, piles, piers, columns, ootings, or walls. Localized scour determi-nations will require knowledge o the food depth, fow conditions, soil characteristics, andoundation type.

    NOTE: Th mthd fdtmining dbis impatlads in ASce 7-02 was

    dvlpd f ivin impat lads

    and has nt bn valatd f astaldbis that may impat a bilding v

    sval wav yls. Althgh thsimpat lads a vy lag bt f sht

    datin, a sttal ngin shldb nsltd t dtmin th sttalspns t th sht lad datin (0.03

    snd mmndd).

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    In some locations, soil at or below the ground surace can be resistant to localized scour, andscour depths calculated below will be excessive. In instances where the designer believes the soilat a site will be scour-resistant, a geotechnical engineer should be consulted beore calculatedscour depths are reduced.

    3.7.1 LocalizedScourAroundVerticalPiles

    The methods or calculating localized scour (Smax) in coastal areas have been largely based onempirical evidence gathered ater storms. Much o the evidence gathered suggests that local-ized scour depths around piles and other thin vertical members are approximately equal to .0to .5 times the pile diameter. Figure 3-5 illustrates localized scour at a pile, with and without ascour-resistant terminating stratum. Currently, there is no design guidance in ASCE 7-02 on howto calculate scour. Localized scour around a vertical pile or similar oundation element shouldbe calculated with the ollowing ormula as given in FEMA 55:

    Smax = 2.0a

    Where

    Smax = Maximum localized scour depth (t)

    a = Diameter o a round oundation element or the maximum diagonal cross-section di-mension or a rectangular element (t)

    Figure3-5.

    Scouratvertical

    oundationmember

    stoppedbyunderlying

    scour-resistantstratum

    Source: COastal

    COnstruCtiOn

    manual

    (FeMA 55)

    3.7.2 LocalizedScourAroundVerticalWallsandEnclosures

    Localized scour around vertical walls and enclosed areas (e.g., typical A Zone construction) canbe greater than that around vertical piles, and should be estimated using Table 3-3.

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    Table3-3.LocalScourDepthasaFunctionoSoilType

    SoilType ExpectedDepth(%ods)

    Ls sand 80

    Dns sand 50

    Sft silt 50

    Stiff silt 25

    Sft lay 25

    Stiff lay 10

    Source: FeMA 55

    3.8 FloodLoadCombinations

    Load combinations (including those or food loads) are given in ASCE 7-02, Sections 2.3.2 and2.3.3 or strength design and Sections 2.4. and 2.4.2 or allowable stress design.

    The basic load combinations are:

    Allowable Stress Design

    () D + F

    (2) D + H + F + L + T(3) D + H + F + (Lr or S or R)

    (4) D + H + F + 0.75(L + T) + 0.75(Lr or S or R)

    (5) D + H + F + (W or 0.7E)

    () D + H + F + 0.75(W or 0.7E) + 0.75L + .5Fa + 0.75(Lr or S or R)

    (7) 0.D + W + H

    (8) 0.D + 0.7 E + H

    Strength Design

    () .4 (D + F)

    (2) .2 (D + F + T) + .(L + H) + 0.5(Lr or S or R)

    (3) .2D + .(Lr or S or R) + (L or 0.8W)

    (4) .2D + .W + L + 0.5(Lr or S or R)

    (5) .2D + .0E + L + 0.2S

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    () 0.D + .W + .H

    (7) 0.D + .0E + .H

    For structures located in V or Coastal A Zones:

    Allowable Stress Design

    Load combinations 5, , and 7 shall be replaced with the ollowing:

    (5) D + H + F + .5Fa + W

    () D + H + F + 0.75W + 0.75L + .5Fa + 0.75(Lr or S or R)

    (7) 0.D + W + H + .5Fa

    Strength Design

    Load combinations 4 and given in ASCE 7-02 Section 2.3. shall be replaced with the ollowing:

    (4) .2D + .W + 2.0Fa + L + 0.5(Lr or S or R)

    () 0.D + .W + 2.0 Fa + .H

    Where

    D = Dead Load

    W = Wind Load

    E = Earthquake LoadFa = Flood Load

    F = Load due to fuids with well dened pressures and maximum heights

    L = Live Load

    Lr = Roo Live Load

    S = Snow Load

    R = Rain Load

    H = Lateral Earth Pressure

    Flood loads were included in the load combinations to account or the strong correlation be-tween food and winds in hurricane-prone regions that run along the Gul o Mexico and theAtlantic Coast.

    In non-Coastal A Zones, or Allowable Stress Design, replace the .5Fa with 0.75Fa in load combi-nations 5, , and 7 given above. For Strength Design, replace coecients W and Fa in equations4 and above with 0.8 and .0, respectively.

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    3 foundation design loads

    Designers should be aware that not all o the food loads will act at certain locations or againstcertain building types. Table 3-4 provides guidance to designers or the calculation o appropri-ate food loads in V Zones and Coastal A Zones (non-Coastal A Zone food load combinationsare shown or comparison).

    The foodplain management regulations enacted by communities that participate in the NFIPprohibit the construction o solid perimeter wall oundations in V Zones, but allow such oun-dations in A Zones. Thereore, the designer should assume that breaking waves will impact pilesin V Zones and walls in A Zones. It is generally unrealistic to assume that impact loads will occuron all piles at the same time as breaking wave loads; thereore, this manual recommends thatimpact loads be evaluated or strategic locations such as a building corner.

    Table3-4.SelectionoFloodLoadCombinationsorDesign

    Case1 PileorOpenFoundationinVZone(Required)

    Fbkp (n all pils) + Fi (n n n itial pil nly)

    Fbkp (n fnt w f pils nly) + Fdyn (n all pils bt fnt w) +Fi (n n n itial pil nly)

    Case2 PileorOpenFoundationinCoastalZZone(Recommended)

    Fbkp (n all pils) + Fi (n n n itial pil nly)

    Fbkp (n fnt w f pils nly) + Fdyn (n all pils bt fnt w) +Fi (n n n itial pil nly)

    Case3 Solid(Wall)FoundationinCoastalAZone(NOTRecommended)

    Fbkp (n walls faing shlin, inlding hydstati mpnnt) +Fdyn;

    assm n n is dstyd by dbis, and dsign in dndany

    Case4 Solid(Wall)FoundationinNon-CoastalAZone(ShownorComparison)

    Fsta + Fdyn

    Source: COastal COnstruCtiOn manual (FeMA 55)