48 Concrete Shear

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CONCRETE SHEAR

Page 48 - 1

TANK SUPPORT

48

At column 39 to 139 Seismic ENGINEERING with the SPREADSHEET Copyright 2006 American Society of Civil Engineers A

B

C

BEARING ON CONCRETE 4 ksi f'c 290 k_ult Punching 1 unitless ratio P_ult 290.0 k_ult f_brg Фbrg A 1 req'd

3.4 ksi_ult 0.7

A2

122 in2 452 in2

multiplier A req'd

2.00 61 in2

D

E

F

G

P_ult

290.0 k_ult

Ao

6786 in2

I

2

J

K

L

M

N

1

along this plane

convert circular column to equivalent square

452.4 in2 452 in² > 122 in²

188 in

H

Figure 48-1 Bearing area and edge distance

A_pl

1.00 unitless 36.0 in

21562345.xls

A 2 is measured

CIRCULAR PUNCHING SHEAR dia 24.00 in

βc d bo

y

ultimate strength of concrete SEISMIC ultimate load LRFD factor required 0.85 * f'c allowable bearing on concrete 11.0 in on a side minimum area of supporting surface not to exceed 2 ACI 10.17.1 A1/A2

Christy 7:14 08/31/09

1.0 * 290.0 ratio = 1 for circular column depth to tension reinforcing (dia + d)*pi bo * d 36.0 * 188

row 30 Critical Section Unloaded Area d/2 Face + d

Vc 33

αs

2575 k

02 ACI 11.12.2.1 (11-33) 6 * (4 * 1000)^0.5 /1000 * 188 * 36.0 where (2 + 4/βc ) = 6 factor (αs d /bo + 2) √ f'c bo d 02 ACI 11.12.2.1 (11-34) (40 * 36.0 /188.5 + 2) * (4 * 1000)^0.5 /1000 * 188 * 36.0

Vc 34

40 unitless 4137 k

Vc 35

1717 k

Ao 4 √ f'c 02 ACI 11.12.2.1 (11-35) 6,786 * 4 * (4 * 1000)^0.5 * 0.85 /1000

Vc min

1717 k

Use minimum Vc for punching shear.

Фv Vu

0.85 unitless

strength reduction factor Ф Vc minimum 1459 k ult OK 290.0 < 1,459 k ultimate allowed

Figure 48-2 Shear punching in plan view.

αs

40 for interior columns 30 for edge columns 20 for corner columns

d

Figure 48-3 Shear cone dimensions in elevation view.

row 60

STIRRUP REINFORCING b1 60.0 in

width of critical section

s fy

stirrup / tie spacing < d/2 or 24" stirrup / tie yield strength

Av

4.0 in 40 ksi 0 in2 =0.31*10

Page 48 - 2

sum of area for all vertical bars to resist shear Note: Calculation for Av is done in the input cell. The actual calculation is copied to an adjacent cell and parked with the [space bar] to show the math.

21562345.xls row 70

Vs

0.0 k

Vu

1459.2 k-ult

Av Fy d /s ACI 11.5.6.2 0.00 * 40 * 36.0 /4.0

d

Ф (Vc minimum + Vs)

0.85 * (1,717 + 0.0) OK 290.0 required < 1,459.2 k ultimate allowed

d/2 Figure 48-4 Shear reinforcing through the shear cone.

INCLINED BAR REINFORCING f'c 4 ksi Vu reqd 290.0 k ult d 36.0 in Vc 1716.7 k ult Фv 0.85 unitless b1 α fy Av

Vs

60.0 in 60.0 degrees 1.047 radians 60 ksi 9.6 in2

498.8 k

but not greater than: bw 72.0 in Vs

Vs use Vu

491.8 k

Per ACI Commentary R11.12.3 In slabs 10" and thinner, shear reinforcement should be enclosed stirrups with a longitudinal bar at each corner.

width of critical section

row 90

angle of shear bars from the plane of beam/column reinforcing α > 30º stirrup / tie yield strength =0.6*12 sum of area for all bars to resist shear

longitudinal reinforcing

Av Fy sin α ACI 11.5.6.5 (11-17) 9.60 * 60 * sin 60.0 width of tributary beam 3 √ f'c bw d 3 * ( 4.00 * 1000)^0.5 * 72.0 * 36.00 /1000

d/2

d

491.8 k 1877.2 k-ult

Ф (Vc minimum + Vs)

0.85 * (1,717 + 491.8) OK 290.0 required < 1,877.2 k ultimate allowed

Figure 48-5 Inclined shear reinforcing. row 110

TORSION Torsion per ACI 11.6.3 Tu 1006286 in-lb/ft ult f'c

Page 48 - 3 =1174*1000*12 /14 ultimate torsional moment

4 ksi

Фtorsion

0.75 factor

Aoh

3456 in2

Acp

3456 in2

pcp

264 in

Column Strip 21562345.xls

row 120

36 For Nonprestressed members Torsional effects on bending and shear can be neglected when Tu Limit < Tu Tu Limit

row 130

Ф √ f'c (Acp2 / pcp) 2146025 in-lb ult TRUE logic OK Tu limit ≥ Tu required Torsion reinforcing not required

96

Figure 48-6 Beam torsion shear. Aoh

ρh

T1

0.007 unitless

0.013

=12*0.6/(24*42) ratio of horizontal shear reinforcing area to gross area of the vertical concrete section

0.000

torsion reinforcement, in2 Acp

area enclosed by the outside perimeter of the concrete cross section, in2

pcp

outside perimeter of the concrete cross section, in

(Vu / bw d)2 (290 /(72.0 * 36.0) )^2

T2

area enclosed by the centerline of the closed

(Tu ρh / 1.7 Aoh2)2 (1,006,286 * 0.007 /(1.7 * 3,456^2) )^2

T required

0.11 k-in ult

√(Vu /bw d)2 + (Tu ρh / 1.7 Aoh2)2

T provided

0.99 k-in ult

Фv ( Vc / bw d + 8 √ f'c ) 0.85 * (1,716.7 /(72.0 * 36.0) + 8 * (4 * 1000)^0.5 /1000)

row 150

row 160

BEAM SHEAR V beam ratio beam Vu req'd f'c d bw

Page 48 - 4 230.0 k 1 unitless 230.0 k_ult 4 ksi 36 in 96 in

=460/2 column punching divided by 2 sides fluid + DL seismic

depth to reinforcing width of beam or tributary slab

Vc

437.2 k

Ф Vu allow

0.85 unitless strength reduction factor 371.6 k_ult 0.85 * 437.2 TRUE logic OK 371.6 > 230.0 k_ult required

s fy

6.0 in 40 ksi

2 √ f'c bw * d ACI 11.3.1.1 2 * (4 * 1000)^0.5 * 36.0 * 96 /1000

stirrup / tie spacing < d/2 or 24" stirrup / tie yield strength

Av

0.00 in2 =0.2*12

sum of area for all bars to resist shear

Av req'd

0.72 in2

50 * bw * s /fy ACI 11.5.5.2 50 * 96 * 6.0 /40.00 /1000

Vs

Vu allow

0.0 k

371.6 k-ult

Av Fy d /s ACI 11.5.6.2 0.00 * 40 * 36.0 /6.0 Ф (Vc + Vs) 0.85 * (437.2 + 0)

FOR MEMBERS SUBJECT TO SHEAR AND FLEXURE As 7.2 in2 area of tension reinforcing =0.6*12 ρw 0.0021 unitless density of tension reinforcing Mu 1174.0 k-ft ult factored ultimate moment limit

7.1

21562345.xls Figure 48-7 Beam shear elevation. Bar 10M 15M 20M 25M 30M 35M 45M

Area 0.12 0.27 0.49 0.76 1.1 1.49 2.47

55M 0 3 4 5 6 7 8 9 10 11 14 18

3.68 0 0.11 0.20 0.31 0.44 0.6 0.79 1.00 1.27 1.56 2.25 4.00

row 180

row 190

Vu d / Mu < 1.0

a b Vc

1.0 0.120 0.005 433.3 k

( 1.9 √f'c + 2500 ρw Vu d / Mu ) bw d ACI 11.3.2.1 1.9 * (4.0 * 1000)^0.5 /1000 2500 * 0.0021 * 1.0 /1000 (0.120 + 0.005) * 96.0 * 36.0

Vc limit

765.0 k

3.5 √ f'c bw * d

Vc

433.3 k

minimum( Vc limit, Vc )

Vu allow

Ф (Vc + Vs) 368.3 k-ult TRUE logic OK 368.3 > 230.0 k_ult required

row 200

ACI 11.3.2.1

row 210

PHOTOGRAPHS

Page 48 - 5

21562345.xls row 220

row 230

row 240

Figure 48-8 Weld stud application. row 250 Weld stud application requires a large generator. The welded end of the stud contains the weld material and flux. The white, porcelan ferrules contain the electric arc, flux, and weld material. After welding, the ferrule is broken off and discarded. You can visit the Nelson Weld Stud site at: http://www.nelsonstud.com row 260 For evaluation reports, go to the International Building Codes Evaluation Service website at: http://www.icbo.org/ICBO_ES/ On February 1, 2003, ICBO ES formally joined with the National Evaluation Service, BOCAI evaluation services, and SBCCI PST & ESI in the new ICC Evaluation Service, Inc. (ICC-ES). ICC-ES is a subsidiary of the International Code Council. The web site address will change in time.

Figure 48-9 The big, portable weld stud generator. row 270

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21562345.xls

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