design of small building

8/9/2019 Design of Small Building

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General Requirements

Step one :

The Direcon of Ri bs and Loadi ng is Chos en .

Step Two ;

Over all slab thickness must be chosen .

Maximum value of thickness to stand against the deflecon i s used f romt he t abl e ( 3-2) of

dr. Samir Shihada Reinforcement Design Book .

Restraint Simply

supported

One end

connuous

Two end

connuous

Canlever

Minimum

thickness

L/16 L/18.5 L/21 L/8

From this table you can reach the worst case by measuring thru ribs and spans and

determine which kind of these in the table sasfy ever y one and by that you can obt ai n the

minimum thickness which sasfy the defleconr equi r ement s :

Aer I do the pr evi ous step I can deci de that the wo r st case is :

L= 445 cm and it is one end connuous ri b so far

The minimum thickness = 445/18.5 = 24.05 cm

take the minimum thickness = 25 cm

it will be divide as 17 cm the thickness of the block and 8 cm concrete .


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Weight of 5-m height wall = 1.55 ton /mr

From the previous informaon you can take the fol lowi ng res ul ts : Dead load of one way ribbed slab = 0.655 ton/m

2

Live load of residenal us es is = 0. 2 ton/ m2

Dead load of 20 cm thickness wall = 0.93 ton/mr

Design Of Ribs

Step six : Take a samples of Ribs , analysis and then Design for Shear and Flexure :

RIB (1)

Dead load = 0.52 0.655 = 0.3406 ton/mr.

Live load = 0.52 0.2 ton/mr

Take this values and enter it to CBEAM sowa r e pr ogr am and you wi ll take the fol lowi ng

S.F.D and B.M.D


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4 f 6 mm U-srrups per me t er is to be us ed to carry the shear for ce and as carri er to boom

flexur al rei nf or ceme nt .

2) Design RIB 1 for flexur al :

Design for the Tension Zone : Design as T- secon :

assume a


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1) Design of RIB 2 for shear :

As the previous rib 1 use the same procedure and u will find the fol lowi ng :

Use 4 f 6 mm @1m

2) Design of RIB 2 for flexur e :

Let a < 5 cm so C= 0.85(b)(a)(fc')

C = 0.85(200)(52)(a)

C= 8.849 a ton .

Mu = f Mn = f C (d-(a/2))

Mu= 1.39

So a2 43.61 a + 34.924 = 0

S 0 816 5


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Design Main Beams

First ; Summary of Procedure :

1) Design for flexur al :

Obtain the S.F.D & B.M.D from the CBM program by the informaon di scus sed before ( length cross secon assume d wi de assume d thi cknes s dead load and

Live load ) then draw and start analysis .

From the previous givens you can find that mu s t be > mi n (= 0. 0033) to us e it in

findi ng Asteel

. = ((0.85)(fc')/(fy))(1-(1-((2.61105 M)/(b(d2)(fc'))) then you can find the Asteel by the formula .

Asteel = bd aer thi s find t he numbe r of the sui t abl e diamet er and mak e c heck t hat the space

sasfy the ACI code (not les s than 2. 5 cm)

S = (b-(2dia srrup + 2dia bar))/(n 1)


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Main Beam (1) :

DL 2.498 2.4333LL 0.31 0.335


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a) Main Reinforcement :

Example Of First span posive Mo me nt zone: ( Mmax )+ve = 4.75 ton.m

Using fc' 200

fy 4200

Mmax +ve 4.75

Using h 25

b 60

Using main reinforcement 14 mm

Srrups 8 mm

So d = 19.5

+ve 0.005934 min 0.0033 use = 0.005934

So . As +ve 6.942219 = 4.512036 bars of 14 mm

Spacing Check

Using

no. of bars = 5 so .. space (S)= 10.45 cm

Example of negave mo me nt :

( Mmax) ve = 8.03 ton.m

Using fc' 200

f 4200


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b) Srrups :

Example of the first span findi ng of requi r ed s rrups : Vu = 7.98 tonsUsing fc' 200

fy 4200

Vu 4.953

So Vu/ 5.827059

Vc 8.769538

Vc 7.454108

Vs -2.94248

Now Make Dimension Check

find 2.1( f'c)(b)(d) 34.74722723

Vs -2.9424794 as long as (Vs) is the smallest so dimension is enough

you will use 1 srrups

Establish ZONES

( f'c)(b)(d) 16.54629868

Vs -2.94247947

if Vs < (fc')(b)(d) so take d

if Vs > (fc')(b)(d) so take d/2

So now use d / 1 = 19.5

N h


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Design of Columns

To find Pu the Comp r es si on for ce in any col umn you mu s t fol low the next two me t hods :

1) Area Method .

2) Recon Me t hod .

And take the biggest of them and design on it .

Now with examples you will understand how we can do this .

1) the Area Method :

Pu total= Pu1 + Pu 2 + Pu3

Pu 1 = Load came from the weight of the Panel .

Pu2 = the load that came from the weight of the beams .

Pu3 = the load that came from the load of the walls .

A) The load from the Panels :

It contains Dead load and Live Load .The Dead Load = 0.655 ton/m2.

The Live Load = 0.2 ton/m2

Now you must find the tot al ar ea of al l the Panel s and mu l ply i t by t he t his fact or 0.655 t o

find the servi ce dead load and by the factor of the live load 0. 2 to find t he t otal Live l oad .

Results :

Total Area of the Panel = 135.4522 m2

So


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The Final results :

Pu total = 255 tons (dead )

Pu total = 27.5 tons (live )Total area of the building = 204 m2

So

Dead load of 1 m2 of Panel = 1.25 tons

Live load of 1 m2 of Panel = 0.2 tons .

Now use these tow values to find the tot al we i ght on ever y col umn by mu l ply i t of the area

that the column have from the slabAnd you will find the fol lowi ng tabl e .

But before it I want to explain How can I have the Pu from the reacon Me t hod

2) Reacon Me t hod :

From the CBM program when you take the informaon for each poi nt you ought to obt ai n

the reacon at eac h suppor t to us e it her e .

Not that the reacon is a Factor ed Ser vi ce Load that you can us e it in the des i gn of the beam with all of easiness , but when you want to design the foong and the load in the col umn

came from the reacon me t hod you wa nt the Ser vi ce load to cal cul at e the ar ea of the

foong .

Here you must return to the CBM program and use it in findi ng the reacon by ent eri ng t he

final load onl y ( summa on of the dead l oad and t he l ive l oad ) wit hout any f act oraonand

find the reacon .


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Service Load from Area Factored Load from Reaction Pu

D.L ( ton/m2) L.L(ton/m2) D.L L.L Service DL+LL Factored load DL+LL Factored load Service Factored

1 4.2278 1.25 0.205882 5.28475 0.87042792 6.15517792 8.878377463 5.636 8.59 6.15517792 8.878377463

2 8.2263 1.25 0.205882 10.282875 1.693647097 11.9765221 17.27522506 15.926 22.78 15.926 22.78

3 6.8209 1.25 0.205882 8.526125 1.404300534 9.930425534 14.32388591 4.395 6.7 9.930425534 14.32388591

4 6.879 1.25 0.205882 8.59875 1.416262278 10.01501228 14.44589587 4.395 6.7 10.01501228 14.44589587

5 7.9375 1.25 0.205882 9.921875 1.634188375 11.55606338 16.66874524 15.926 22.78 15.926 22.78

6 4.2278 1.25 0.205882 5.28475 0.87042792 6.15517792 8.878377463 5.636 8.59 6.15517792 8.878377463

7 6.035 1.25 0.205882 7.54375 1.24249787 8.78624787 12.67349638 10.505 15.63 10.505 15.63

8 12.0338 1.25 0.205882 15.04225 2.477542812 17.51979281 25.27097278 21.624 31.16 21.624 31.16

9 9.8719 1.25 0.205882 12.339875 2.032446516 14.37232152 20.73098408 5.811 9.07 14.37232152 20.73098408

10 10.0181 1.25 0.205882 12.522625 2.062546464 14.58517146 21.03800399 5.811 9.07 14.58517146 21.03800399

11 11.8875 1.25 0.205882 14.859375 2.447422275 17.30679728 24.96374287 21.624 31.16 21.624 31.16

12 6.0869 1.25 0.205882 7.608625 1.253183146 8.861808146 12.78248635 10.505 15.63 10.505 15.63

13 11.8362 1.25 0.205882 14.79525 2.436860528 17.23211053 24.8560129 19.146 28.18 19.146 28.18

14 13.7875 1.25 0.205882 17.234375 2.838598075 20.07297308 28.95374173 19.79 31.26 19.79 31.26

15 13.5027 1.25 0.205882 16.878375 2.779962881 19.65833788 28.3556619 19.375 30.73 19.375 30.73

16 13.5269 1.25 0.205882 16.908625 2.784945226 19.69357023 28.40648188 20.443 31.26 20.443 31.26

17 12.0643 1.25 0.205882 15.080375 2.483822213 17.56419721 25.33502276 19.228 28.18 19.228 28.18

18 8.4662 1.25 0.205882 10.58275 1.743038188 12.32578819 17.77901492 17.014 21.044 17.014 21.044

19 9.7825 1.25 0.205882 12.228125 2.014040665 14.24216567 20.54324413 13.842 23.639 13.842 23.639

20 9.5028 1.25 0.205882 11.8785 1.95645547 13.83495547 19.9558743 15.636 23.258 15.636 23.258

21 9.5969 1.25 0.205882 11.996125 1.975828966 13.97195397 20.15348424 13.842 23.639 13.842 23.639

22 8.4662 1.25 0.205882 10.58275 1.743038188 12.32578819 17.77901492 17.014 21.044 17.014 21.044


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Finding the suitable cross sections of the columns :

no Pu slab no Pu acuall fc' fy g Ag required C1 C2 C2 accrual Ag accuall As1 As2 As max Using no. of bars accuall no of bars

1 8.8783775 5 44.3919 250 4200 0.01 314.101 20 15.70505 40 800 3.141 4 4 12 3.5368 6

2 22.78 5 113.9 250 4200 0.01 805.915 20 40.29576 50 1000 8.059 5 8.06 12 7.1259 8

3 14.323886 5 71.6194 250 4200 0.01 506.753 20 25.33766 50 1000 5.068 5 5.07 12 4.4807 6

4 14.445896 5 72.2295 250 4200 0.01 511.07 20 25.55348 50 1000 5.111 5 5.11 12 4.5188 6

5 22.78 5 113.9 250 4200 0.01 805.915 20 40.29576 50 1000 8.059 5 8.06 12 7.1259 8

6 8.8783775 5 44.3919 250 4200 0.01 314.101 20 15.70505 40 800 3.141 4 4 12 3.5368 6

7 15.63 5 78.15 250 4200 0.01 552.961 20 27.64806 50 1000 5.53 5 5.53 12 4.8893 6

8 31.16 5 155.8 250 4200 0.01 1102.38 25 44.09538 50 1250 11.02 6.25 11 14 7.1612 8

9 20.730984 5 103.655 250 4200 0.01 733.425 20 36.67124 50 1000 7.334 5 7.33 12 6.4849 8

10 21.038004 5 105.19 250 4200 0.01 744.287 20 37.21433 50 1000 7.443 5 7.44 12 6.5809 8

11 31.16 5 155.8 250 4200 0.01 1102.38 25 44.09538 50 1250 11.02 6.25 11 14 7.1612 8

12 15.63 5 78.15 250 4200 0.01 552.961 20 27.64806 50 1000 5.53 5 5.53 12 4.8893 6

13 28.18 5 140.9 250 4200 0.01 996.957 25 39.8783 50 1250 9.97 6.25 9.97 12 8.815 8

14 31.26 5 156.3 250 4200 0.01 1105.92 25 44.23689 50 1250 11.06 6.25 11.1 14 7.1842 8

15 30.73 5 153.65 250 4200 0.01 1087.17 25 43.48687 50 1250 10.87 6.25 10.9 14 7.0624 8

16 31.26 5 156.3 250 4200 0.01 1105.92 25 44.23689 50 1250 11.06 6.25 11.1 14 7.1842 8

17 28.18 5 140.9 250 4200 0.01 996.957 25 39.8783 50 1250 9.97 6.25 9.97 14 6.4764 8

18 21.044 5 105.22 250 4200 0.01 744.499 20 37.22493 50 1000 7.445 5 7.44 12 6.5828 8

19 23.639 5 118.195 250 4200 0.01 836.305 20 41.81526 50 1000 8.363 5 8.36 12 7.3946 8

20 23.258 5 116.29 250 4200 0.01 822.826 20 41.1413 50 1000 8.228 5 8.23 12 7.2754 8

21 23.639 5 118.195 250 4200 0.01 836.305 20 41.81526 50 1000 8.363 5 8.36 12 7.3946 8

22 21.044 5 105.22 250 4200 0.01 744.499 20 37.22493 50 1000 7.445 5 7.44 12 6.5828 8


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Dividing all Columns in Groups :

groups from to Column no. Pu representative column

Service Factored

1 40 60 1 66.155178 8.878377

12 60 80 3 4 7 12 10.505 15.63 7

3 80 100

4 100 120 2 5 9 10 18 19 20 21 22 13.842 23.639 19

5 120 140 13 17 19.146 28.18 13

6 140 160 8 11 14 15 16 20.443 31.26 14

The final result is :

group 1 1 20 40 6 12

group 2 7 20 50 6 12

group 3 19 20 50 8 12

group 4 13 25 50 8 12

group 5 14 25 50 8 14


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Example :

Footing for Group (1)

Pu service Column dimension

Footing no. fc' fy DL LL q all (net) C1 C2 H Area (m2) B L L

1 250 4200 30.775 17.72 20 40 30 1.7367381 1.35 1.286473 1.35Df 1.2

soil 1.7

Y conc 2.5 Pu factored qult (net) d

q gross 20 44.3913 24.35736626 12 21.3

Check footing thickness for punching shear Check footing thickness for beam shear

Vu bo bc as Vc is the Largest of Vc long direction short direction

38.2247699 205.2 2 40 73.254251 73.2542505 112.666 62.26611296 Vu Vc Vu Vc

73.25425054 11.903445 20.48227 8.6152 20.48227

as long as Vc > Vu so thickness is enough

Long Direction steel Mu As min As min As no.

3.709551 0.001625708 4.67472226 0.0018 7.29 7.29 12 6.445775

Short Direction steel Mu As min As min As no.

5.435879 0.002400965 6.90397379 0.0018 7.29 7.29 12 6.445775


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Example:

Footing for Group (4):

Pu survice Column dimention


1 250 4200 95.73 17.6 25 50 45 5.4392045 2.35 2.314555 2.35

Df 1.2soil 1.7

Y conc 2.5 Pu factored qult (net) d

q gross 20 140.9 25.51380715 12 36.3



127.402711 295.2 2 40 179.5969 179.596905 310.644 152.6573691 Vu Vc Vu Vc

179.5969048 41.190766 60.76301 33.69609 60.76301



25.65055 0.002237202 19.0844475 0.0018 19.035 19.08445 14 12.39749


33.05154 0.002902209 24.7572965 0.0018 19.035 24.7573 14 16.08264


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Example for Groub (5-b) :

Pu survice Column dimention


1 250 4200 98.95 17.56 25 50 50 5.6349658 1.8 3.130537 3.15

Df 1.2

soil 1.7Y conc 2.5 Pu factored qult (net) d

q gross 20 156.95 27.68077601 12 41.3



140.1943 315.2 2 40 218.17859 218.17859 394.964 185.4518012 Vu Vc Vu Vc

218.1785897 31.564389 92.66706 45.44076 52.95261



43.73736 0.003913728 29.0946555 0.0018 16.2 29.09466 18 11.43348


26.18558 0.001303961 16.9638763 0.0018 28.35 28.35 18 11.14085

All Results with clear drawings is shown in the Map Eppendix


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22

18

1920

21


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A A112,L=2m

212,L=7.5m

112,L=1.5m

212,L=4.5m

2218

1920

21

C3C3C3

C3C3


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6 mm mesh @25 cm6 mm stirrups@25 cm 112


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B4B4 B4

B4 B4

B7B8

B8B8B7

B2B2

B4

22

18

1920

21

314314314314214

114 214

312

212

212

212

212


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414314214

214

314

114414

414414

114214

414

114

B1

B2

B3


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201918

2221

20 10.55m

18-19-21-22 10.75m


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Beams

B1

B2

B3

B4

Dimentions

W id th H ie gh t

2560

2580

2580

2560

B OT TO M R EI NF . T O P R EI NF . S TI RR UP S AT END

O F SP AN O F SP AN

IN THEMIDDLE

214

414

414

214

414

414

414

314

114

214

114

214

414

414

214

18@15

18@15

18@15

18@15 18@20

18@20

18@20

18@20


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2120

19

1822

F3F3F3

F3F3


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F1

F2

F3

F4 F5


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2019

182221

GB2GB2 GB2

GB2

Ground Beam

GB (1-2-3-4)

Dimentions Bottom Reinf. StirrupsType

Width Height

Top Reinf.

All Beam Mid SupportAll beam

212 212212 212 58 @ 20 cm

All Beam

25 50

design of small building

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