Eccentric Footing

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Transcript of Eccentric Footing

  • PROJECT : CLIENT : JOB NO. : DATE :

    Eccentric Footing Design Based on ACI 318-14

    INPUT DATA DESIGN SUMMARYCOLUMN WIDTH = 5 in FOOTING WIDTH BCOLUMN DEPTH = 5 in FOOTING LENGTH LBASE PLATE WIDTH = 16 in FOOTING THICKNESS TBASE PLATE DEPTH = 16 in LONGITUDINAL REINF., TOP

    FOOTING CONCRETE STRENGTH = 2.5 ksi LONGITUDINAL REINF., BOT.

    REBAR YIELD STRESS = 60 ksi TRANSVERSE REINF., BOT.AXIAL DEAD LOAD = 50 kAXIAL LIVE LOAD = 4.5 kLATERAL LOAD (0=WIND, 1=SEISMIC) = 0 Wind,SDWIND AXIAL LOAD = 1 k, SDWIND MOMENT LOAD = 15 ft-k, SDWIND SHEAR LOAD = 2.5 k, SD

    SURCHARGE = 0.1 ksf

    SOIL WEIGHT = 0.11 kcf

    FOOTING EMBEDMENT DEPTH = 2 ftFOOTING THICKNESS T = 12 in

    ALLOW SOIL PRESSURE = 3 ksfFOOTING WIDTH = 10 ft

    = 6 ftFOOTING LENGTH = 6 ft

    = 1 ftREINFORCING SIZE # 5

    THE FOOTING DESIGN IS ADEQUATE.

    ANALYSIS

    CASE 1: DL + LL P = 55 kips 1.2 DL + 1.6 LLM = 136 ft-kipse = 2.5 ft, fr cl ftg

    CASE 2: DL + LL + 0.6(1.3) W P = 55 kips 1.2 DL + LL + 1.0 WM = 152 ft-kipsV = 2 kipse = 2.7 ft, fr cl ftg

    CASE 3: DL + LL + 0.6(0.65) W P = 55 kips 0.9 DL+ 1.0 WM = 146 ft-kipsV = 1 kipse = 2.7 ft, fr cl ftg

    9.2 > F = 1.0 / 0.9 = 1.11 [Satisfactory]Where 17 k-ft

    (0.15 kcf) T B L = 16.80 k, footing weight

    12.32 k, soil weight

    152 k-ft

    FOR REVERSED LATERAL LOADS,

    28.7 > F = 1.0 / 0.9 [Satisfactory]Where 14 k-ft

    402 k-ft

    1.5 2.25 kips < 26.72 kips [Satisfactory]

    Where ` 0.4

    c1c2b1b2fc'

    fyPDLPLL

    PLATMLATVLAT

    qswsDf

    QaB1B2L1L2

    DESIGN LOADS AT TOP OF FOOTING (IBC 1605.3.2 & ACI 318 5.3)PuMueuPuMuVueuPuMuVueu

    CHECK OVERTURNING FACTOR (2015 IBC 1605.2.1, 1808.3.1, & ASCE 7-10 12.13.4)MR / MO =

    MO = MLAT + VLAT T - PLATL2 =

    Pftg =

    Psoil = ws (Df - T) B L =

    MR = PDLL2 + 0.5 (Pftg + Psoil) L =

    MR / MO =

    MO = MLAT + VLAT Df - PLATL1 =

    MR = PDLL1 + 0.5 (Pftg + Psoil) L =

    CHECK SLIDING (2015 IBC 1807.2.3)(VLat, ASD) = W =

    =

  • Service Loads CASE 1 CASE 2 CASE 3P 54.5 55.3 54.9 ke 2.5 2.8 2.7 ft (from center of footing)

    11.2 11.2 6.7 k, (surcharge load)

    4.5 4.5 2.7 k, (footing increased)70.2 71.0 64.3 k1.9 > L/6 2.2 > L/6 2.3 > L/6 ft1.6 < B/6 1.6 1.7 < B/6 ft30.0 35.5 35.4 k / ft

    3.0 3.5 3.6 ksf

    3.0 4.0 4.0 ksf

    Where

    DESIGN FLEXURE & CHECK FLEXURE SHEAR (ACI 318 13, 21, & 22)

    FACTORED SOIL PRESSURE Factored Loads CASE 1 CASE 2 CASE 3

    67.2 65.5 46.0 k

    2.5 2.8 2.9 ft

    17.9 11.2 0.0

    34.9 34.9 26.2 k, (factored footing & backfill loads)

    120.1 111.6 72.2 k

    1.4 > L/6 1.6 > L/6 1.8 > L/6 ft

    2.381 2.479 1.807 ksf

    Section 0

    0 1.50 3.00 4.50 5.56 6.44 6.25 6.50 6.75

    0 0 0 0 0 -29.4 -16.8 -33.6 -50.4

    0 0.0 0.0 0.0 0.0 67.2 67.2 67.2 67.2

    2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56

    0 -2.9 -11.5 -25.9 -39.6 -53.0 -50.0 -54.1 -58.3

    0 3.8 7.7 11.5 14.2 16.5 16.0 16.6 17.3

    4.99 4.99 4.99 4.99 4.99 4.99 4.99 4.99 4.99

    0 -5.6 -22.5 -50.5 -77.2 -103.4 -97.5 -105.5 -113.7

    0 7.5 15.0 22.5 27.8 32.1 31.2 32.4 33.7

    0.00 0.51 1.02 1.53 1.89 2.19 2.13 2.21 2.30

    0 189.5 288.9 316.3 302.3 275.2 282.0 272.8 262.9

    0 -48.2 -84.1 -107.8 -117.2 -120.3 -120.0 -120.3 -120.4

    0 181.1 254.9 239.8 185.5 89.3 117.7 79.7 40.5

    0 -36.9 -61.5 -73.8 -75.2 -4.5 -5.6 -4.0 -2.2

    CHECK SOIL BEARING CAPACITY (ACI 318 13.3.1.1)

    qs B L

    (0.15-ws)T B L P

    eLeB < B/6qL

    qmaxqallow

    Pueu

    qs B L k, (factored surcharge load)[0.15T + ws(Df - T)]BL

    Pueu

    qu, max

    FOOTING MOMENT & SHEAR AT LONGITUDINAL SECTIONS FOR CASE 10.25 L1 0.50 L1 0.75 L1 ColL ColR 0.25 L2 0.50 L2 0.75 L2

    Xu (ft, dist. from left of footing)

    Mu,col (ft-k)

    Vu,col (k)

    Pu,surch (klf)

    Mu,surch (ft-k)

    Vu,surch (k)

    Pu,ftg & fill (klf)

    Mu,ftg & fill (ft-k)

    Vu,ftg & fill (k)

    qu,soil (ksf)

    Mu,soil (ft-k)

    Vu,soil (k)

    Mu (ft-k)

    Vu (kips)

    ''2

    0.85 1 10.383

    Muf c b fd cf y

    40.0018 ,3MIN

    TMINd

    61,

    62

    ,3(0.5 ) 6

    L

    LL

    LL

    ePLL for eLq

    P Lfor eL e

    61,

    62

    ,3(0.5 ) 6

    BL

    BMAX

    LB

    B

    eqBB for eq B

    q Bfor eB e

    61

    ,6,

    2,

    3 (0.5 ) 6

    MAX

    euPu LL for euBLquLPu for euB L eu

    '10.85

    MAX

    f c uf u ty

  • Section 0

    0 1.50 3.00 4.50 5.56 6.44 6.25 6.50 6.75

    0 0 0 0 0 -11.2 1.1 -15.3 -31.6

    0 0.0 0.0 0.0 0.0 65.5 65.5 65.5 65.5

    1.60 1.60 1.60 1.60 1.60 1.60 1.60 1.60 1.60

    0 -1.8 -7.2 -16.2 -24.8 -33.2 -31.3 -33.8 -36.5

    0 2.4 4.8 7.2 8.9 10.3 10.0 10.4 10.8

    4.99 4.99 4.99 4.99 4.99 4.99 4.99 4.99 4.99

    0 -5.6 -22.5 -50.5 -77.2 -103.4 -97.5 -105.5 -113.7

    0 7.5 15.0 22.5 27.8 32.1 31.2 32.4 33.7

    0.00 0.53 1.06 1.59 1.97 2.28 2.21 2.30 2.39

    0 175.5 262.7 280.9 262.4 233.1 240.2 230.6 220.4

    0 -47.3 -81.8 -103.6 -111.4 -112.9 -113.0 -112.9 -112.4

    0 168.0 233.0 214.1 160.4 85.3 112.6 76.1 38.6

    0 -37.4 -62.1 -74.0 -74.7 -5.0 -6.3 -4.5 -2.4

    Section 0

    0 1.50 3.00 4.50 5.56 6.44 6.25 6.50 6.75

    0 0 0 0 0 -2.6 6.0 -5.5 -17.0

    0 0.0 0.0 0.0 0.0 46.0 46.0 46.0 46.0

    0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

    0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

    0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

    3.74 3.74 3.74 3.74 3.74 3.74 3.74 3.74 3.74

    0 -4.2 -16.8 -37.9 -57.9 -77.6 -73.1 -79.1 -85.3

    0 5.6 11.2 16.8 20.8 24.1 23.4 24.3 25.3

    0.00 0.00 0.77 1.16 1.44 1.66 1.61 1.68 1.74

    0 0.0 167.1 174.0 158.4 136.9 142.0 135.1 127.8

    0 0.0 -55.7 -69.7 -73.9 -73.9 -74.2 -73.8 -73.1

    0 -4.2 150.2 136.1 100.5 56.7 74.9 50.5 25.5

    0 5.6 -44.5 -52.8 -53.1 -3.8 -4.8 -3.4 -1.8

    DESIGN FLEXURE

    Location d (in) useTop Longitudinal -4.2 ft-k 9.69 0.0001 0.0001 0.0129 no limit 1 # 5Bottom Longitudinal 254.9 ft-k 8.69 0.0025 0.0041 0.0129 18 23 # 5 @ 8 in o.c.Bottom Transverse 1 ft-k / ft 8.38 0.0004 0.0003 0.0129 18 6 # 5 @ 15 in o.c.

    CHECK FLEXURE SHEAR

    DirectionLongitudinal 75.2 k 125 k [Satisfactory]Transverse 4.3 k / ft 8 k / ft [Satisfactory]

    Case y R J1 67.2 168.0 18.9 18.9 0.5 0.4 1.0 2.0 112.0 4.4 1.5 1.92 65.5 178.8 18.9 18.9 0.5 0.4 1.0 2.0 112.0 4.4 1.4 1.93 46.0 130.0 18.9 18.9 0.5 0.4 1.0 2.0 112.0 4.4 1.0 1.9

    where = 0.75 , (ACI 318 21.2)

    FOOTING MOMENT & SHEAR AT LONGITUDINAL SECTIONS FOR CASE 20.25 L1 0.50 L1 0.75 L1 ColL ColR 0.25 L2 0.50 L2 0.75 L2

    Xu (ft, dist. from left of footing)

    Mu,col (ft-k)

    Vu,col (k)

    Pu,surch (klf)

    Mu,surch (ft-k)

    Vu,surch (k)

    Pu,ftg & fill (klf)

    Mu,ftg & fill (ft-k)

    Vu,ftg & fill (k)

    qu,soil (ksf)

    Mu,soil (ft-k)

    Vu,soil (k)

    Mu (ft-k)

    Vu (kips)

    FOOTING MOMENT & SHEAR AT LONGITUDINAL SECTIONS FOR CASE 30.25 L1 0.50 L1 0.75 L1 ColL ColR 0.25 L2 0.50 L2 0.75 L2

    Xu (ft, dist. from left of footing)

    Mu,col (ft-k)

    Vu,col (k)

    Pu,surch (klf)

    Mu,surch (ft-k)

    Vu,surch (k)

    Pu,ftg & fill (klf)

    Mu,ftg & fill (ft-k)

    Vu,ftg & fill (k)

    qu,soil (ksf)

    Mu,soil (ft-k)

    Vu,soil (k)

    Mu (ft-k)

    Vu (kips)

    Mu,max min reqD max smax

    Vu,max Vc = 2 b d (fc')0.5 check Vu < Vc

    CHECK PUNCHING SHEAR (ACI 318 13.2.7.2, 22.6.4.1, 22.6.4.3, & 8.4.2.3)

    Pu Mu b1 b2 b0 v c Af Ap

    0.5 1( )

    231 21 3

    6 1 1

    1 2

    R bMP uu vpsivu JAP

    db d bJb b

    b bPuRA f

    2 1 2112 113 2

    db bAP

    v bb

    BLA f

    '( ) 2

    42, , 400

    , 0.5 0.5 , 0.5 0.50 1 1 1 2 2 2

    psi y fvc c

    dy MINbc

    AP d db b c b b c bd

  • PAGE : DESIGN BY : REVIEW BY :

    = 16.00 ft= 7.00 ft= 12 in

    1 # 5

    23 # 5 @ 8 in o.c.

    6 # 5 @ 15 in o.c.

    = 67 kips= 168 ft-kips= 2.5 ft, fr cl ftg= 66 kips= 179 ft-kips= 3 kips= 2.7 ft, fr cl ftg= 46 kips= 130 ft-kips= 3 kips= 2.8 ft, fr cl ftg

  • (cont'd)

    ft (from center of footing)

    k, (surcharge load)

    k, (footing increased)

    [Satisfactory]

    k, (factored footing & backfill loads)

    L

    7.00

    -67.2

    67.2

    2.56

    -62.7

    17.9

    4.99

    -122.3

    34.9

    2.38

    252.2

    -120.1

    0

    0

    k, (factored surcharge load)

  • (cont'd)

    L

    7.00

    -48.0

    65.5

    1.60

    -39.2

    11.2

    4.99

    -122.3

    34.9

    2.48

    209.5

    -111.6

    0

    0

    L

    7.00

    -28.5

    46.0

    0.00

    0.0

    0.0

    3.74

    -91.7

    26.2

    1.81

    120.2

    -72.2

    0

    0

    0.00020.00430.0026

    [Satisfactory]

    105.3 150.0102.7 150.072.2 150.0

    [Satisfactory]

    provD

    vu (psi) vc

    '( ) 2

    42, , 400

    , 0.5 0.5 , 0.5 0.50 1 1 1 2 2 2

    psi y fvc c

    dy MINbc

    AP d db b c b b c bd

  • INPUT DATA DESIGN SUMMARYCOLUMN WIDTH = 5 in FOOTING WIDTH BCOLUMN DEPTH = 5 in FOOTING LENGTH LBASE PLATE WIDTH = 16 in FOOTING THICKNESS TBASE PLATE DEPTH = 16 in LONGITUDINAL REINF. #REF! #

    FOOTING CONCRETE STRENGTH = 2.5 ksi TRANSVERSE REINF. #REF! #

    REBAR YIELD STRESS = 60 ksiAXIAL DEAD LOAD = 50 kAXIAL LIVE LOAD = 4.5 kLATERAL LOAD (0=WIND, 1=SEISMIC) = 0 Wind,SDWIND AXIAL LOAD = 1 k, SDWIND MOMENT LOAD = 0 ft-k, SDWIND SHEAR LOAD = 0 k, SD

    SURCHARGE = 0.1 ksf

    SOIL WEIGHT = 0.11 kcf

    FOOTING EMBEDMENT DEPTH = 2 ftFOOTING THICKNE