8/12/2019 2 Design of Beam Ledges 23052014

1/2

Sheet :

Cont'd :

fc' =

fy =

=

x + x

== x + x =

1) =

Lb = mm wb = mm Ab = cm2 =

= = =

= = > =

=

2)

The reaction is considered at outer third point of bearing pad.

d =

a) cover =

a = lb*(2/3) + 25 mm = mm d' =

= mm

Vu = +

= x+

x =

b)

Assume mm cover and mm bar stirrups.

af = a + cover + bar stps/2 = mm

:. Effective width flexure = Ewf = Wb + 5af = mm

3)

Pnb = (0.85fc'Ab) where =

= > Vu =

4)

for fc = 30 mpa Vn (max) = min( 800 * ew * d' , 0.2 *fc' * ew * d' ) = kn

:. Vn = > Vu =

5)

Avf = Vu / ( * fy * ) = mm2 / per effective width of Ew. = mm = mm2 / m

where =

6) Check for punching shear

Vups = 4 * * fc^0.5 * ( Wb + 2Lb + 2de ) * de where Wb = mm =

= kn > Vu = Lb = mm

de = mm (assumed)

7)

Nu = max ( 0.2Vu , T ) = kn

An = Nu / fy = mm2 / per effective width of mm = mm2 / m

8)

Mu = Vu * af + Nu * (d - de) = kn.m find Af using conventional flexural design methods. For beam ledges

Af = mu / fy jd = mm = mm2 / m use jd = 0.8 and

= 0.85.

9)

As = max ( 2 * Avf / 3 + An , Af + An, As(min) ) = mm2 / m As (min) = 0.04 * ( fc / fy ) * b *de

= mm2 / m

10) Ah = 0.5 ( As - An ) = mm2 / m

try mm dia bar ar = mm2 = use @ c/c

PrepBy:ABQuadri-AbqConsultants-9959010210-em-abquadri@yahoo.com-12-2-826/2RoyalResidency,BesidesAmbatalkies,Mehdipatnam,Hyderabad-India.500028-www.abqconsultants.com

12 113 max spacing Smax 279 mm 12 125 ok

Determine primary tension reinforcement :- As

948

556 (11.9.5)

Determine Shear reinforcement :- Ah 405 (reinforcement within 2/3 d and close top As)

Determine flexural reinforcement : - Af

74.92

1168 mm2 / per effective width of Ew. = 1442 810

190

Determine reinforcement to resist direct tension (Nu) : - An

69

199 1442 138

400 0.85

346.79 346.32 kn ok 200

Determine Shear friction reinforcement.

710 1033 687

1.4 (11.7.4.1) (11.7.4.3)

(9.3.2.4)

Check effective ledge section for maximum nominal shear transfer strength Vn

1083

920.45 kn 346.32 kn ok (11.9.3.2.1)

208

1442

Check concrete bearing strength.

0.7 (10.17.1)

1428.00 kn 346 kn ok

100 346 kn

For flexure : critical section is at c/l of hanger r/f (Av)

40 20

1.4 * Pdl 1.7 * Pll

1.4 126 1.7

158 ( 9.2.1) 190 mm

Effective width = Ew = Wb + 4a 1033

Determine Shear Span and effective widths for both shear and flexure

Depth

230 mm

For shear friction 40 mm

T 65 kn

Bearing Capacity of plate 385.84 kn 225.94 kn ok

Allowable Bearing Capacity 700 psi 4.823 mpa Total Pdl 126 kn

Pll 100 kn

Beam reactions (service load)

Check Bearing pad size : sw of ledge 5.942 kn

200 400 800 Pdl 120 kn

kn

Total dead load + live load (ultimate) 1.4 126 1.7 100 346 kn

Total dead load + live load (service) 1.0 126 1.0 100 226

Calculation sheet

Design of Beam Ledge as per ACI 318M

95

note : enter data in blue cells only. 30 mpa

Pdl Pll410 mpa

Verified by : Revision Notes :

Project :

Subject :

Prepared by : Date :Job No. :

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8/12/2019 2 Design of Beam Ledges 23052014

2/2

Sheet :

Cont'd :

11) As = mm2 / m

try mm dia bar ar = mm2 max spacing Smax = mm use @ c/c

12) Av = Vu * s / ( * fy * S ) = mm2 For s = c/c and S = c/c

For serviceability : Av = ( V / 0.5 * fy ) * ( s / ( Wb + 3 * af )) = mm2 (governs) :. Av = mm2

s = stirrup spacing

S = Support Spacing

use @ c/c

Bw- beam width

Bearing pad

x x

Main Reinforcement

Horizontal Reinforcement

Vertical Reinforcement

Reactions on Main Beam due to Ledge load

=

Kn

Kn.m

Kn

Kn.m

1033

max

PrepBy:ABQuadri-AbqConsultants-9959010210-em-abquadri@yahoo.com-12-2-826/2RoyalResidency,BesidesAmbatalkies,Mehdipatnam,Hyderabad-India.500028-www.abqconsultants.com

M (dl+ll - ultimate) = 95

V (dl+ll - service ) = 226

M (dl+ll - service) = 62

V (dl+ll - ult ima te ) = 346

12 @ 100

Beam Ledge dimension and reinforcement datails

230 Bw -width of beam

125 c/c

250 min

125 125

230

12 @ 125

Thickness of bearing pad as per

manufacturers recommendations.

200 L 400 W t

20 @

note : suffic ient stirrups for c ombined shear and torsion must be provided for

global effects in the ledge beam :

Final Ledge reinforcement 20 125 ok

Check required area of hanger reinforcement : 83 125 1500

157 157

Calculation sheet

Determine final size and spacing of ledge reinforcement 948

16 201 212 16 125 ok

Verified by : Revision Notes :

Project :

Subject :

Prepared by : Date :Job No. :