Thesis Paper on Longer Span Floor Beams System of Edge Supported Structures (Part 2)
Subject: Architecture | Topics:

CHAPTER VI

STRUCTURAL DESIGN OF TYPE-IIBUILDING

Introduction:

In this chapter, the four storied building is analyzed and designed by ultimate strength design (USD) method as per discussions made in Chapter III and references provided by Winter and Nilson (1997 & 2003). For space limitations, one set of design example is presented here in detail from each component of the building such as slab, floor beam, column, grade beam and footing. The cross-sectional dimensions along with reinforcement arrangement of the rest are shown in a tabular form. Finally full design of the stair case has been provided.

Analysis and design of building components

 Design of slab:

All slab panels are analyzed and designed by following the ‘ACI Moment Coefficient procedure’ (Appendix I). Typical floor plan and panel plan are given in Appendix VII and Appendix VIX respectively. Analysis and design of panel groups (S-1~S-3) are presented below.

Design data

Design procedure – ACI moment Co-efficient

Materials:

                                                     = 40 ksi

                                                    = 3 ksi

                                                     = 150 pcf

                                           = 120 pcf

Loadings:

                     F.F + Partition wall        = 30 psf

                     L.L                                 = 40 psf

Slab Panel S -1

Panel size                                            = 28′-2″×20′-6″

Beam width                                        = 12″

Clear span size                                    =27′-2″×19′-0″

Panel ratio,

Panel type                                           = Two-way slab (Case – 4)

1) Load calculation:

Slab thickness

Self weight of slab

Floor finish +P-wall                      = 30 psf.

Live load                                       = 40 psf.

Factored load = 1.2 WDL + 1.6 WLL

                        = 1.20 × (81.25+30) +1.6×40

                        = 197.5 psf

ll) Moment calculation:

 Support moment:  

Mid span moment:

lll) Check for d :

Maximum moment = 5775.09 lb-ft.

Check for d

lV) Reinforcement calculation:

A. Short direction steel

Steel for positive moment at mid span

< 200 psi

Use # 3 bar which area = 0.11

Spacing

Use # 3 @  alternate cranked bars.

Alternative bars should be cranked both at continuous and discontinuous edges.

Steel for negative moment at both supports

So provided 1# 3 bar extra top between two ckd. bars.

B. Long direction steel

Steel for positive moment at mid span

(+)ve MB = 1745.49 lb – ft

Spacing

Use # 3 @  alternate cranked bars.

Alternative bars should be cranked both at continuous and discontinuous edges.

Steel for negative moment at both supports

                     (-)ve MB = 2770.12 lb – ft

So provide 1-# 3 bar extra top between two ckd. bars.

Slab Panel S-2

Panel size                                            = 7′-0″×5′-8″

Beam width                                        = 12″

Clear span size                                    = 6′-0″×4′-8″

Panel ratio,

Panel type                                           = Two-way slab (Case – 2)

1) Load calculation:

Slab thickness

Self weight of slab

Floor finish +P-wall                      = 30 psf.

Live load                                       = 40 psf.

Factored load = 1.2 WDL + 1.6 WLL

                        = 1.20× (62.50+30) +1.6×40

                        = 175 psf

ll) Moment calculation:

 Support moment:

Mid span moment:

lll) Check for d:

Maximum moment = 371.31 lb-ft.

Check for d 4

                                

lV) Reinforcement calculation:

A. Short direction steel

Steel for positive moment at mid span

Use # 3 bar which area = 0.11

Spacing

Use # 3 @  alternate cranked bars.

Alternative bars should be cranked both at continuous and discontinuous edges.

Steel for negative moment at both supports

So provided 1 # 3 bar extra top in between two ckd. bars.

B. Long direction steel

Steel for positive moment at mid span

(+)ve MB = 105.02 lb – ft

Spacing

Use # 3 @  alternate cranked bars.

Steel for negative moment at both supports

-MB = 214.37 lb – ft

Crank to crank spacing

So provide 1-# 3 extra top between two ckd. bars.

Slab Panel S -3          

I) Check for one-way slab        

Panel size                                            = 7′-0″×15′-6″

Beam width                                        = 12″

Length, L=15′-0″ and width, w          =7′-0″

Panel ratio,

So the slab will be designed as one-way slab.

II) Calculation of slab thickness:

Minimum slab thickness

Thickness correction for

Corrected thickness, h = 3″×0.80 =2.40″

Slab thickness let, h =4″

Effective depth, d = 4 -1=3″

III) Moment calculation:

L L= 40 psf

Factored load =1.2×DL+1.6×LL = 1.2×80+1.6×40 =160 psf = 0.16 ksf

(+)ve moment at mid span   

(-)ve  moment at interior support

lV) Check for d:

Maximum design moment= 0.784 k-ft

V) Reinforcement calculation

A. Temperature & shrinkage steel.

Use # 3 bar as Temperature steel.

Use # 3 bar @ 13.50” c/c.

B. Main bar

(-)ve Moment at Interior support = 0.784 k-ft

(-)ve As  for Int. support = ρbd = 0.0023×12×3=0.083 in2/ft

(+)ve Moment at mid span = 0.56 k-ft.

We provided # 3 as main steel

Spacing at mid span =

So spacing at mid span =

A detail of slab reinforcement arrangement of all panels (S-1 ~ S-3) is given in Table 6.1 and Figure 6.1.

Bar arrangement, cut-off and bent up, bar spacing etc. are done as per discussions and ACI/BNBC Codes provisions presented in Chapter III.

Table 6.1: Details of slab reinforcement arrangement of all Panels (S-1~S-3

Panel

Length

(feet)

Moment  

(pound-feet)

Area of steel

inch (sq.)/ft

Spacing 

(inch c/c)

LA

LB

Negative

Positive

Negative

Positive

Negative

(Extra top in between crank)

Positive

(Main bar)

LA

LB

LA

LB

LA

LB

LA

LB

LA

LB

LA

LB

S-1

19

27.17

5775.09

2770.12

3279.68

1745.49

0.343

0.33

0.33

0.30

#3-1

#3-1

#3 @ 4″#3 @4″

S-2

6

14.91

784

—–

560

—–

0.083

0.062

0.072

#3-1

—–

#3 @ 12″

#3 @12″

S-3

5.67

6

371.31

214.37

183.28

105.02

0.24

0.21

0.10

0.21

#3 -1

#3-1

#3 @ 5.5″

#3 @ 5.5″

LA – Short direction

LB – Long directionDetails of slab reinforcement arrangement of all Panels

Design of floor beam:

All floor beams are analyzed and designed by following the ‘ACI Moment Coefficient procedure’ (Appendices I & XVI). Typical lay-out plan of all floor beams is given in Appendix-XI. Analysis and design of all beam groups (F. B – 1~F.B-6) are presented below.

Design data

Design procedure = ACI moment Co-efficient

Materials:

                                         =  60 ksi

= 3 ksi

= 150 pcf

= 120 pcf

Main wall thickness                = 5″

Floor beam F.B-1

Let depth of beam        =25″

Beam size                     =12″×25″

l) Load calculation:

Self weight of beam                 =

Main wall / Partition wall weight

Load coming from slabs

S-1                      DL      =111.25× 19′×0.5×0.81×2= 1712.13   lb / ft

Total dead load, DL      = 312.50+396+1712.13=2420.63 lb/ft

Live load, LL                = 40×19′-0″×0.5×0.81×2 = 615.60   lb / ft 

Factored load                 = 1.2DL+1.6LL = 1.2×2420.63+1.6×615.60 =3889.72 lb/ft

=3.89   k / ft

ll) Moment calculation & d check: 

(-) ve moment at Ext. support =

(+) ve moment at mid span =

(-) ve moment at Int. support =

T-beam check

For interior beam

center to center distance of the beam =20′-0″ =240″

will be the smallest of the above, = 81.5″

Let, a = slab thickness = 6.5″

And assume it is a singly beam.

So it is not a T-beam.

Considering double layers of steel, effective depth of the beam, d= 25″-4″= 21″

Check for‘d

Maximum Moment = 287.16 k-ft

lll) Reinforcement calculation:

(+)ve steel at mid span

(- )ve Steel at exterior support

(- )ve Steel at Interior support

IV) Stirrup design:
Shear at 1st Interior support,

Critical shear at d distance,

Concrete shear strength,

Allowable strength,

Since, <  , So stirrup is required.

Shear carried by stirrup =71.85-20.71=51.14 k

Floor beam F.B-2

Let, beam width          =12″

Depth of beam=

Take beam size                        = 12″×20″

l) Load calculation:

Self weight of beam F.B-2     =

All main wall weight

Load coming from slab, S-1 = 111.25×19′-0″×0.81/2 = 856.06   lb / ft

Total dead load, DL             = 250+416.5+856.06 = 1522.56 lb / ft

Live load from slab, S-1      = 40×19′-0″x0.81/2 = 307.80   lb / ft

Total factored load              = 1.2DL+1.6LL

= 1.2×1522.56+1.6×307.80 = 2319.55 lb-ft =2.32   k / ft

ll) Moment calculation: 

(-)ve moment at Ext. support =       =

(+)ve moment at mid span     =       =

(-)ve moment at Int. support  =       =

III) T-beam& d check:

T-beam check

Center to center beam distance=12+0.5×(19′-0″)×12=126″

will be the smallest of the above, =39.17″

Let, a= slab thickness = 6.5″ and assume it is a singly beam

So it is not a T-beam, and it will be designed as a singly beam

Effective depth of the beam, d =20-4 =16″ (considering double layer of steel)

Check for d

Maximum moment, =171.33 k-ft

lV) Reinforcement calculation:

(+)ve steel at mid span

(-)veSteel at Interior support

(-)ve Steel at exterior support

V) Stirrup design:
Shear at 1st Interior support,

Critical shear at ′d′ distance,

Concrete shear stress,

Allowable stress,

Since, <  , so stirrup is required.

Shear carried by stirrup =28.32-17.25=11.07 k

Floor beam F.B-3

Let, beam width   = 12″

Depth of beam     =15″

Size of beam        =12″×15″

l) Load calculation:

Self weight of beam F.B-3     =

All main wall weight

Load coming from slab, S-1 = 111.25×27′-2″×0.19/2 = 287.15   lb / ft

Total dead load, DL             = 187.50+437.50+287.15 = 912.15 lb / ft

Live load from slab, S-1      = 40×27′-2″×0.19/2 = 103.25   lb / ft

Total factored load              = 1.2DL+1.6LL

= 1.2×912.15+1.6×103.25= 1259.76 lb-ft =1.26   k / ft

ll) Moment calculation: 

(-)ve moment at Ext. support =       =

(+)ve moment at mid span     =       =

(-)ve moment at Int. support  =       =

III) T-beam& d check:

T-beam check

(Center to center beam distance) =12+0.5 × (27′-2″) ×12=175″

will be the smallest of the above, = 31″

Let, a = slab thickness = 6.5″

And assume it is a singly beam

So it is not a T-beam, it will be designed as a singly beam.

Now effective depth of the beam, d =15-2.5 = 12.5″ (considering one layer of steel).

Check for d

Maximum moment, =45.48 k-ft

lV) Reinforcement calculation:

(+)ve steel at mid span

(-)ve Steel at Interior support

(-)ve Steel at exterior support

V) Stirrup design:
Shear at 1st Interior support,

Critical shear at ′d′ distance,

Concrete shear stress,

Allowable stress,

Since, <  , so stirrup is required.

Shear carried by stirrup = 16.60-12.32 = 4.28 k

Floor beam F.B-4

Let, beam width   = 12″

Depth of beam     = 15″

Size of beam        = 12″×15″

l) Load calculation:

Self weight of beam F.B-4     =

Self weight of 5″ wall

Load coming from slab, S-1   = 111.25×27′-2″×0.19/2 = 287.15   lb / ft

Load coming from slab, S-3   = 80×7/2 = 280 lb/ft

Total dead load, DL               = 187.50+437.50+287.15+280 = 1192.15 lb / ft

Live load from slab, S-1         = 40×27′-2″x0.19/2 = 103.25   lb / ft

Live load from slab, S-3         =40×7/2=140 lb/ft

Total live load, LL                 = (103.25+140.00) =243.24 lb/ft

Total factored load                 = 1.2DL+1.6LL

= 1.2×1192.15+1.6×243.24= 1819.76 lb-ft =1.82 k / ft

ll) Moment calculation: 

(-)ve moment at Ext. support =       =

(+)ve moment at mid span     =       =

(-)ve moment at Int. support  =       =

Maximum moment, = 65.70 k-ft

III) T-beam& d check:

T-beam check

(Center to center beam distance)=12+0.5×(27′-2″)×12=175″

will be the smallest of the above, =31″

Let, a=slab thickness=6.5″ and assume it is a singly beam

So it is not a T-beam, and it will be designed as a singly beam

Now effective depth of the beam, d=15-2.5=12.5″ (considering one layer of steel)

Check for d

Maximum moment, =65.70 k-ft

lll) Reinforcement calculation :

(+)ve steel at mid span

(-)veSteel at Interior support

(-)veSteel at exterior support

IV) Stirrup design:
Shear at 1st Interior support,

Critical shear at d distance,

Concrete shear stress,

Allowable stress,

Since, <  , So stirrup is required.

Shear carried by stirrup =23.86-12.32=11.54 k  

Floor beam F.B-5

Let, beam width   = 12″

Depth of beam     =12″

Size of beam        =12″×12″

Effective depth, d =12-2.5=9.5″

l) Load calculation:

Self weight of beam F.B-5     =

Self weight of  5″ wall

Load coming from slab, S-1 = 111.25×27′-2″×0.19/2 = 287.15   lb / ft

= (150+437.50+287.15) = 874.65 lb/ft

Live load from slab, S-1       = 40×27′-2″x0.19/2 = 103.25   lb / ft

Factored load (B to C)          = 1.2DL+1.6LL

=1.2×874.65+1.6×103.24=1214.76 lb/ft

Dead load slab, S-3               = 0.55/2×92.50×6′-0″ = 152.62 lb / ft

Live load from slab, S-3      = 0.55/2×40×6′-0″ = 66 lb / ft

Factored load                                   = 1.2DL+1.6LL

=1.2×152.62+1.6×66 = 288.74 lb/ft

Sub total load (A to B)        =1214.76+288.74=1503.50 lb/ft=1.50 k/ft

Concerted load at point “D”

Dead load from stair beam =

Dead load from stair          =

Dead load from slab, S-3   =118×3                                =354.00 lb/ft

= (375.00+279.30+354.00) = 3528.30 lb

Live load from stair           =

Live load from slab, S-3    =51.03×3′-0″           =153.09 lb

= (1999.50+153.09)=2152.59 lb

Factored load                                 = 1.2DL+1.6LL

= 1.2×3528.30+1.6×2152.59= 7678.10 lb =7.68   kip

ll) Moment calculation & d check: (moment calculation by GRAPS software}

(-)ve moment at Int. support = 49.63 k-ft

(-)ve moment at Ext. support  =39.32 k-ft

(+)ve moment at mid span     =37.35 k-ft

(-)ve moment at point   “B”    = 34.53 k-ft

Check for d

Maximum moment, =49.63 k-ft

Ill) Reinforcement calculation:

(+)ve steel at mid span

(-)veSteel at Interior support

(-)veSteel at exterior support

IV) Stirrup design:

:∑

and
Shear at 1st Interior support,

Critical shear at d distance,

Concrete shear stress,

Allowable shear stress,

Since, <  , So stirrup is required.

Shear carried by stirrup =27.05-9.38=11.54 k

Floor beam F.B-6

Let, beam width   = 12″

Depth of beam     = So taken beam depth=10″

Size of beam        =12″×10″

Effective depth, d =10-2.5=7.5″

l) Load calculation:

Self weight of beam    FB-6        =

Load coming from slab, S-2       =

All main wall weight                  =

Total dead load, DL                 

Live load from slab, S-2

Total factored load                      = 1.2DL+1.6LL

ll) Moment calculation & d check: 

(-)ve moment at both. Supports =       =

(+)ve moment at mid span     =       =

Check for d

Maximum moment, = 4.18 k-ft

lll) Reinforcement calculation:

(+)ve steel at mid span

(-)veSteel at both support

IV) Stirrup design:
Shear at 1st Interior support,

Critical shear at d distance,

Concrete shear stress,

Allowable shear stress,

Since, > , so stirrup is not required.

Use 2 legs # 3 @ 3.5″ c/c throughout the beam length.

Floor beam F.B -7(Stair beam)

Let, beam width   = 12″

Depth of beam     =10″

Size of beam        =12″×10″

Effective depth, d =10-2.5 = 7.5″

l) Load calculation:

Self weight of beam                    =

Load coming from slab, S-2       =

Load coming from stair,             =

Total dead load, DL                 

Live load from slab, S-2

Live load from stair

Total live load, LL

Total factored load                      = 1.2DL+1.6LL

ll) Moment calculation & d check: 

(-)ve moment at both. Supports =       =

(+)ve moment at mid span     =       =

Check for d

Maximum moment, =14 k-ft

lll) Reinforcement calculation:

(+)ve steel at mid span

(-)veSteel at both support

IV) Stirrup design:
Shear at 1st Interior support,

Critical shear at d distance,

Concrete shear stress,

Allowable shear stress,

Since, <  , So stirrup is required.

Shear carried by stirrup  =8.71-7.38=1.33 k

Details of sectional dimensions and reinforcement arrangement of all floor beams (FB -1 ~ FB-7) are given in Table 6.2 and Figure 6.2~6.6.

Bar arrangement, cut-off and bent up, bar spacing etc. are done as per discussions and ACI/BNBC Codes provisions presented in Chapter III.

 Details of sectional dimensions and reinforcement arrangement of all floor beams (FB -1 ~ FB-7)

Floor beam

group

Floor beam

size

Moment

(kip-ft)

Area of steel req.

(sq. inch)

Quantity of bars

Stirrups

 (spacing, c/c)

At Ext.

M-ve

At Mid

M+ve

At Int.

M-ve

At Ext.

As-ve

At mid

As+ve

At Int.

M-ve

Main bars

Extra top

Use 2 Legs “U”

#3 bar

F.B-1

12’’25″

179.48

205.11

287.11

2.016

2.268

3.528

At Ext. suppt: 4 # 5+2# 6

@ 4.0″c/c

At mid span  : 4 # 6+2# 5

@ 4.0″c/c

At Int. suppt.: 4 # 5+2# 6

2- # 7

@ 4.0″c/c

F.B-2

12”20″

170.04

122.33

171.26

1.44

1.536

2.30

At Ext. suppt: 5 # 5

@ 8.5″c/c

At mid span  : 5 # 5

@ 8.5″c/c

At Int. suppt.: 5 # 5

1- # 8

@ 8.5″c/c

F.B-3

12”15″

28.42

32.49

45.48

0.495

0.672

0.90

At Ext. suppt: 2 #5

@ 6.0″c/c

At mid span  : 2 # 6

@ 6.0″c/c

At Int. suppt.: 2# 5

1- # 5

@ 6.0″c/c

F.B-4

12”12″

41.06

32.49

65.70

0.60

0.75

1.275

At Ext. suppt: 2 # 5

@ 6.0″c/c

At mid span : 2# 6+1# 5

@ 6.0″c/c

At Int. suppt.: 3 # 5

2- # 5

@ 6.0″c/c

F.B-5

12”12″

39.32

37.35

49.63

1.2

1.08

1.31

At Ext. suppt: 2 # 5

@ 6.0″c/c

At mid span  : 2# 6+1# 5

@ 6.0″c/c

At Int. suppt.: 3 # 5

2- # 5

@ 6.0″c/c

F.B-6

12”10″

4.18

2.88

4.18

0.297

0.297

0.297

At Int. suppt.: 2 #5

@ 3.5″c/c

At mid span.: 2 #5

@ 3.5″c/c

At Int. suppt.:2 #5

@ 3.5″c/c

F.B-7

(Stair beam)

12”10″

14.00

9.00

14.00

0.46

0.297

0.46

At Int. suppt.: 2 #5

@ 3.5″c/c

At mid span.: 2 #5

@ 3.5″c/c

At Int. suppt.:2 #5

@ 3.5″c/c

Details of slab reinforcement arrangement of all Panels

CHAPTER VII 

ESTIMATION & COST ANALYSYS 

General:

This chapter gives detailed estimation of volume of concrete and steel which are done separately both for Type-I and Type-II Structures. Finally, cost analyses are completed according to “schedule of rate for civil works”, 12th edition, Public Works Department (PWD).

 Estimate of volume of concrete for Type-I structure.

Volumes of concrete works for different structural elements of the structure are estimated as below (A~F):

A. Volume of concrete of footings

 Footing base:

F-1                               = 4 x 59 x 69 x 1799                           = 170.00 cft

F-2                               = 10 x 69 x 79 x 2099                         = 701.40 cft

F-3                               = 4 x 89 x 99 x 2299                           = 527.04 cft

Volume of concrete of all footing bases                                 = 1398.44 cft

 Pedestal columns:

C-1                              = 4 x 1399 x 1399 x 39-799                = 16.81 cft

C-2                              = 10 x 1399 x 1599 x 39-499              = 45.09 cft

C-3                              = 4 x 1399 x 1799 x 39-999                = 19.46 cft

Volume of concrete of all pedestal columns                           = 181.36 cft

Total volume of concrete of all footings                                 = 1579.80 cft

B. Volume of concrete of grade beams

GB-1                           = 6 x 409 x 1099 x 1299                     = 200.00 cft

GB-2                           = 3 x 649 x 1099 x 1099                     = 132.27 cft

Volume of concrete of all grade beams                                  = 332.27 cft

C. Volume of concrete of columns

C-1                              = 4 x 1099 x 1099 x 89-899                = 24.08 cft

C-2                              = 10 x 1099 x 1299 x 89-899              = 72.25 cft

C-3                              = 4 x 1299 x 1499 x 89-899                = 40.45 cft

Volume of concrete of all columns                                         = 136.78 cft

D. Volume of concrete of floor beams

F.B-1 & F.B-3             = 4 x 409 x 1299 x 1199                     = 146.66  cft

F.B-2                           = 2 x 409 x 1299 x 1399                     =    86.67 cft

F.B-4 & F.B-5             = 3 x 649 x 1299 x799                        = 111.36  cft

Volume of concrete of all floor beams                                   = 344.69 cft

E. Volume of concrete of slabs

S-1                               = 2 x 149 x 229 x 599                         = 252.56 cft

S-2                               = 2 x 149 x 229 x 599                         = 252.56 cft

S-3                               = 2 x 149 x 189 x 599                         = 202.64 cft

S-4                               = 2 x 149 x 189 x 599                         = 202.64 cft

S-5                               = 89 x 189 x 599                                 =   59.04 cft

+ 89 x 99-699 x 599                            =   31.16 cft

Volume of concrete of all slabs                                              = 1000.6 cft

F. Volume of concrete of stair

Waist slab                    = 2 x 129-699 x 39-999 x 699            = 46.88 cft

Tread & Rise               = 2 x 0.5 x 1099 x 6’ x 39-999           = 14.04 cft

Volume of concrete of stair                                                    = 60.92 cft

Total volume of concrete (A to F) for ground floor           = 3455.06 cft

Total volume of concrete for typical floor                          = 1542.99 cft

 Estimate of volume of steel for Type-I structure.

Volumes of steel for different structural elements of the structure are estimated as below (A~F):

  1. A.    Volume of steel of footings

I. Footing base:

Group

No’s  of footing

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

F-1

4

10

5.5

220

#5

0.482

106.04

F-2

10

14

6.5

910

#5

0.482

438.62

F-3

4

21

8.5

714

#5

0.482

344.14

 

 

 

 

Long direction: 

Group

No’s  of  footing

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

F-1

4

9

4.5

162

#5

0.482

78.08

F-2

10

12

5.5

660

#5

0.482

318.12

F-3

4

18

7.5

540

#5

0.482

260.28

 

 

 

 

Short direction:     

Main bars

Group

No’s  of column

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

C-1

4

4

6.5

104

#5

0.482

50.12

C-2

10

4

6.5

260

#5

0.482

125.32

C-3

4

8

6.5

208

#5

0.482

100.25

Tie bars

Group

No’s  of column

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

C-1

4

4

3.83

61.28

#3

0.189

11.58

C-2

10

4

4.16

166.4

#3

0.189

31.45

C-3

4

4

4.5

72

#3

0.189

13.61

Volume of steel of all pedestal columns (main bars + ties) = 332.33 kg

Total volume of steel of all footings                                    = 1877.61 kg

B. Volume of steel of grade beams

Main steel:

Group

No’s  of beam

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

GB-1

6

4

66.5

1596

#5

0.482

769.27

GB-2

3

4

42.5

510

#5

0.482

245.82

 

 

 

Extra top bars:

Group

No’s  of beam

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

GB-1

6

1

11

66

#5

0.482

31.81

 

 

 

Stirrups:

Group

No’s  of beam

No’s  of bar

Length of bar

(ft)

RFT

 

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

GB-1

6

127

3.16

2408

#3

0.189

455.17

GB-2

3

155

2.83

1316

#3

0.189

248.74

 

 

 

Volume of steel of all grade beams = 1750.81 kg

C. Volume of steel of columns

Main bars:

Group

No’s  of column

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

C-1

4

4

12

192

#5

0.482

92.54

C-2

10

4

12

480

#5

0.482

231.36

C-3

4

6

12

288

#6

0.753

216.86

Tie bars:

Group

No’s  of column

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

C-1

4

11

2.83

124.52

#3

0.189

23.53

C-2

10

11

3.41

375.1

#3

0.189

70.90

C-3

4

11

3.83

168.52

#3

0.189

31.85

Volume of steel of all columns = 667.04 kg

D. Volume of steel of floor beams

Main bars:

Group

No’s  of beam

No’s  of bar

Length of bar

(ft)

RFT

 

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

F.B-1

F.B-3

4

4

42.5

680

#6

0.753

512.04

F.B-2

2

4

42.5

340

#7

0.908

308.72

F.B-4

F.B-5

3

4

66.5

798

#5

0.482

384.63

Extra top bars:

Group

No’s  of beam

No’s  of bar

Length of bar

(ft)

RFT

 

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

F.B-1

F.B-3

4

2

6

48

#5

0.482

23.13

4

2

11

88

#7

0.908

79.90

4

2

11

88

#6

0.753

66.26

F.B-2

2

2

6

24

#5

0.482

11.56

2

2

11

44

#8

1.173

51.61

2

2

11

44

#6

0.753

33.13

F.B-4

F.B-5

3

4

4

48

#5

0.482

23.13

Stirrups:

Group

No’s  of beam

No’s  of bar

Length of bar

(ft)

RFT

 

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

F.B-1

F.B-3

4

68

4.16

1131.5

#3

0.189

213.88

F.B-2

2

80

4.5

720

#3

0.189

136.09

F.B-4

F.B-5

3

122

3.5

1281

#3

0.189

242.14

Volume of steel of all floor beams = 2086.22 kg

E. Volume of steel of slab

Long direction:

Type of bars

Length of bar

(ft)

RFT

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

Straight bar

2 x 16 x 42’+ 5 x 22’

1454

#3

0.189

275.81

Cranked bar

2 x 16 x 44’+ 4 x 23’

1500

#3

0.189

283.50

Extra  bar

2 x 16 x 22’+ 5 x 17’

789

#3

0.189

149.12

 

 

 

 

Short direction:

Type of bars

Length of bar

(ft)

RFT

Size of bar

Wt. of bar

(kg/ft)

Volume of steel

(kg)

Straight bar

2 x 23 x 30’+ 14 x 7’

1478

#3

0.189

279.34

Cranked bar

2 x 23 x 32’+ 13 x 7’

1563

#3

0.189

295.41

Extra bar

2 x 23 x 16.5’

+ 21 x 4’

843

#3

0.189

159.33

 

 

 

 

Volume of steel of all slabs = 1442.51 kg

F. Volume of steel of stair

Type of bars

Length of bar

(ft)

RFT

Size of bar

Wt. of Bar

(kg/ft)

Volume of steel

(kg)

Straight bar

8 x 19’

152

#3

0.189

28.73

Cranked bar

7 x 20’

140

#3

0.189

26.46

Extra bar

8 x (2 x 2’- 6”+10’)

120

#3

0.189

22.68

Temperature bar

17 x 7’

119

#3

0.189

22.49

 

Volume of steel of stair = 100.36 kgground floor      = 7924.55 kg

Total volume of steel for typical floor                     = 4296.13 kg

Estimate of volume of concrete for Type-II structure:

Volumes of concrete works for different structural elements of the structure are estimated as below (A~F):

A. Volume of concrete of footings

I. Footing base:

F-1                   = 4 × 6′-6″ × 69-6″×1′-3″                               =211.25  cft

F-2                   = 2 × 89-3″×89-3″ ×1′-9″                               = 238.21 cft

F-3                   = 2 ×69-6″×69-6″×1′-6″                                 =126.75  cft

F-4                  = 2 ×69-6″×69-6″ ×1′-6″                                 =126.75  cft

F-5                  =1×179-0″×109-3″×1′-10″                              = 318.87 cft

Volume of concrete of all footing bases                                 = 1021.83 cft

ll. Pedestal columns:

C-1                  = 4×1399×1399×39-999                                 = 17.60 cft

C-2                  = 2×1699× 1699× 39-399                               = 11.50 cft

C-3                  = 2 ×1399 ×1399× 39-699                             = 8.22  cft

C-4                  = 2 ×1399 × 1399 × 39-699                            = 8.22  cft

C-5                  = 2×1899×1899 × 39-699                               = 15.75 cft

Volume of concrete of all pedestal columns                           =61.29 cft

Total volume of concrete of all footings                                 = 1083.12 cft

B. Volume of concrete of grade beams:

GB-1             =1× (56′-0″×0′-1099×1′-3″                               =58.10   cft

GB-2             = 2×56′-9″×0′-10″×1′-3″                                  =117.76 cft

GB-3             = 2×37′-7″×0′-10″×1′-0″                                  =62.38   cft

GB-2             = 2×37′-3″×0′-10″×1′-0″                                  =61.83   cft

Volume of concrete of all grade beams                                  = 300.49 cft

C. Volume of concrete of columns:

C-1                  = 4×0′-10″×0′-10″×109-099                           = 27.56 cft

C-2                  = 2×1′-1″×1′-1″ ×109-099                              = 23.32 cft

C-3                  = 2×0′-10″×0′-10″ ×109-099                          = 13.78 cft

C-4                  = 2×0′-10″×0′-10″ ×109-099                          = 13.78 cft

C-5                  = 2×1′-3″×1′-3″ ×109-099                              = 31.25 cft

Volume of concrete of all columns                                         = 109.69 cft

D. Volume of concrete of floor beams:

F.B-1            = 2×27′-2″×1′-0″×29-199                                 = 113.02 cft

F.B-2             = 4×27′-2″×1′-0″×19-899                                 = 181.49 cft

F.B-3             = 4×19′-0″×1′-0″×19-399                                  =95.00   cft

F.B-4             = 2×19′-0″×1′-0″×19-399                                 =47.50    cft

F.B-5             = 2×19′-0″×1′-0″×19-399                                 =47.50    cft

F.B-6             = 1×6′-0″×1′-0″×09-1099                                 =4.98      cft

Stair beam     = 1×6′-0″×1′-0″×09-1099                                 =4.98     cft

Volume of concrete of all floor beams                                   =494.47 cft 

E. Volume of concrete of slabs:

S-1                   = 4×27′-2″×19′-0″×                                = 1118.50 cft

S-2                   = 1×6′-0″×4′-8″×                                      = 11.67    cft

S-3                   = 1×14′-6″×6′-0″×                                                = 29.00    cft

Volume of concrete of all slabs                                               = 1159.17 cft

F. Volume of concrete of stair:

Waist slab                    = 2×9′-0″×3′-9″×                          = 28.12 cft

Landing                       =2×9′-0″×3′-9″×                           = 18.75 cft

Tread & Rise               = 2 ×0.5×1099×6″× 39-999×10          = 15.56 cft

Volume of concrete of stair                                                    = 62.43 cft

Total volume of concrete (A to F) for ground floor           =3209.37 cft

 

Total volume of concrete for typical floor                          =1825.76 cft

 Estimate of volume of steel for Type-II structure:

Volumes of steel for different structural elements of the structure are estimated as below (A~F):

B.     Volume of steel of footings:

I. Footing base:

Group

No’s of footing

No’s of bar

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

F-1

4

11×2

6.25

550

#5

0.482

265.10

F-2

2

21×2

8.5

714

#5

0.482

344.15

F-3

2

14×2

6.5

364

#5

0.482

175.45

F-4

2

14×2

6.5

364

#5

0.482

175.45

F-5

1

21

16.5

346.50

#6

0.753

260.91

 

41

9.75

399.75

#5

0.482

192.67

 

 

 

 

 

Both directions

Volume of steel of all footing bases =1445.36 kg

ll. Pedestal columns:

Main bars

Group

No’s of column

No’s of bar

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

C-1

4

4

6.5

104

#5

0.482

50.12

C-2

2

6

6.5

78

#5

0.482

37.59

C-3

2

4

6.5

52

#5

0.482

25.06

C-4

2

4

6.5

52

#5

0.482

25.06

C-5

2

4

6.5

52

#5

0.482

25.06

 

2

4

6.5

52

#8

1.176

61.15

Tie bars:

Group

No’s of column

No’s of bar

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

C-1

4

6

2.83

67.92

#3

0.189

12.84

C-2

2

6

3.83

9.96

#3

0.189

1.88

C-3

2

6

2.83

33.96

#3

0.189

6.418

C-4

2

6

2.83

33.96

#3

0.189

6.418

C-5

2

4

4.5

36

#3

0.189

6.804

Volume of steel of all pedestal columns (main bars + ties) = 258.42 kg

Total volume of steel of all footings                                  = 1703.78 kg

B. Volume of steel of grade beams

Main steel:

Group

No’s of column

No’s of bar

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

GB-1

1

4

66.5

226

#5

0.482

128.21

GB-2

2

4

66.5

532

#5

0.482

256.42

GB-3

2

4

42.5

340

#5

0.482

163.88

GB-4

2

4

42.5

340

#5

0.482

163.88

 

 

 

 

Extra top bars:

Group

No’s  of column

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

GB-1

3

2

12.25

73.5

#5

0.482

35.43

GB-2

3

2

12.25

73.5

#5

0.482

35.43

GB-3

4

1

13.91

55.64

#6

0.753

    41.89

GB-4

4

1

13.91

55.64

#6

0.753

    41.89

 

 

 

 

Stirrups:

Group

No’s  of column

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

GB-1

1

117

3.33

389.61

#3

0.189

43.64

GB-2

2

117

3.33

779.22

#3

0.189

147.27

GB-3

2

98

2.83

554.68

#3

0.189

104.83

GB-4

2

98

2.83

554.68

#3

0.189

104.83

 

 

 

 

Volume of steel of all grade beams = 1297.09 kg

C. Volume of steel of columns

Main bars:

Group

No’s of column

No’s of bar

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

C-1

4

4

12

192

#5

0.482

 92.54

C-2

2

6

12

144

#5

0.482

 69.40

C-3

2

4

12

96

#5

0.482

 46.27

C-4

2

4

12

96

#5

0.482

 46.27

C-5

2

4

12

96

#5

0.482

 46.27

 

2

4

12

96

#8

1.176

 112.89

Tie bars:

Group

No’s  of column

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

C-1

4

11

2.83

124.52

#3

0.189

23.53

C-2

2

11

3.83

84.26

#3

0.189

15.92

C-3

2

11

2.83

124.52

#3

0.189

23.53

C-4

2

11

2.83

124.52

#3

0.189

23.53

C-5

2

11

4.5

99

#3

0.189

18.71

Volume of steel of all columns = 518.87 kg

D. Volume of steel of floor beams

Main bars:

Group

No’s  of column

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

F.B-1

 

2

4

30.67

245.36

#5

0.481

118.02

 

2

4

30.67

245.36

#6

0.753

184.75

F.B-2

4

4

30.68

490.88

#5

0.481

236.11

 

4

3

30.68

368.16

#6

0.753

277.22

F.B-3

2

4

42.50

340

#5

0.481

163.54

F.B-4

2

2

21.25

85

#6

0.753

64.00

 

2

      2

21.25

85

#5

0.481

40.88

F.B-5

2

4

21.25

170

#5

0.481

81.77

 

2

1

21.25

42.50

#6

0.753

32.00

F.B-6

1

4

9

36

#5

0.481

17.32

S. Beam

1

4

9

36

#5

0.481

17.32

Extra top bars:

Group

No’s of column

No’s of bar

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

F.B-1

 

1

4

8′-10″×2

35.32

#7

0.908

32.07

F.B-2

 

4

1

6′-6″

26.00

#7

0.908

23.61

F.B-3

2

1

10′-0″

20.00

#6

0.753

15.06

F.B-4

2

2

5′-9″

23.00

#6

0.753

17.32

F.B-5

2

2

5′-9″

23.00

#6

0.753

17.32

 

2

1

5′-9″

   11.83

#6

0.753

8.91

Stirrups:

Group

No’s  of column

No’s  of bar

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

F.B-1

1

82

5.6

918.40

#3

0.189

173.57

F.B-2

4

39

4.67

728.52

#3

0.189

137.69

F.B-3

4

38

    3.83  582.16

#3

0.189

110.02

F.B-4

2

38

   3.83 291.08

#3

0.189

55.01

F.B-5

2

38

  3.33 253.08

#3

0.189

47.83

F.B-6

1

21

      3.00  63

#3

0.189

11.91

S. Beam

1

21

      3.00  63

#3

0.189

11.91

Volume of steel of all floor beams = 1874.00 kg

E. Volume of steel of slab

Long direction:

Type of bars

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

Straight bar

 4× 29× 28′- 11″

3353.56

#3

0.189

633.82

Ckd bar 4× 28× 35′- 4″

3956.96

#3

0.189

747.86

Extra top bar

 4× 7′-7″×28   848.96

#3

0.189

160.45S

Extra top bar

(23+23+10+10)×8′-10″582.78

#3

0.189

110.14

Straight bar

16×6′-9″108.00

#3

0.189

10.41

Ckd bar

17×7′-1″120.36

#3

0.189

22.74

Extra top bar

 8×6′-9″54.00

#3

0.189

10.21

Extra top bar

 9×7′-1″49.56

#3

0.189

9.37

 

 

 

 

 

 

Short direction:

Type of bars

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

Straight bar

      2×41× 40′- 9″

3341.50

#3

0.189

631.54

Ckd bar

2×40× 41′- 10″

3346.40

#3

0.189

632.46

Extra top bar

      2×41× 10′- 0″

2410.00

#3

0.189

455.49

Extra top bar

      2×2× 5′- 8″

22.68

#3

0.189

4.28

Binder

      8× 16′- 3″

130.00

#3

0.189

24.57

Straight bar

      7× 6′- 8″

46.69

#3

0.189

8.82

Ckd bar

      6× 7′- 3″

43.50

#3

0.189

8.22

Extra top bar

      6× 5′- 6″

33.00

#3

0.189

6.23

Extra top bar

      6× 4′- 9″

28.50

#3

0.189

5.39

 

 

 

 

 

 

Volume of steel of all slabs = 3459.26 kg

F. Volume of steel of stair

Type of bars

Length of bar

(ft)

RFT

Size of bar

Weight of bar

(kg/ft)

Volume of steel

(kg)

Straight bar

  4×2×19′- 0″

152

#3

0.189

28.73

Ckd bar

3×2×20′- 0″

120

#3

0.189

22.68

Extra top bar

4×4×9′- 6″

152

#3

0.189

28.73

Binder

26×3′- 6″

91

#3

0.189

17.20

 

Volume of steel of stair =97.34 kg

Total volume (A to F) of steel for ground floor      =8950.34 kg

Total volume of steel for typical floor                     = 5949.47 kg

Cost analysis of volume of concrete & steel for Type-I structure

This cost analyses, shown in Table 7.1, are completed according to “schedule of rate for civil works”, 12th edition, Public Works Department.

Table 7.1: Cost analysis of volume of concrete & steel for Type-I structure.

Sl. No.

Short Description

Unit

Total

Rate in Taka

Amount in Taka

I

Concrete works

 

 

 

 

A.

Foundation (Footing)
Concrete

cft

1398.44

213.30

298287.25

B.

Grade beam
Concrete

cft

332.27

213.30

70873.19

C.

Pedestal column, column.
Concrete
i.   Below PL level and in Ground Floor

cft

181.36

215.80

39137.49

ii.   Ground Floor

cft

136.78

219.30

29995.85

iii.  1st Floor

cft

136.78

222.80

30474.58

iv.  2nd Floor

cft

136.78

226.30

30953.31

v.  3rd Floor

cft

136.78

229.80

31432.04

D.

Beam:
Concrete
i.   Ground Floor

cft

344.69

213.30

73522.38

ii.  1st Floor

cft

344.69

216.80

74728.79

iii.  2nd Floor

cft

344.69

220.30

75935.21

iv.  3rd Floor

cft

344.69

223.80

77141.62

E.

Roof slab etc.
Concrete
i.   Ground Floor

cft

1000.60

213.30

213427.98

ii.  1st Floor

cft

1000.60

216.80

216930.08

iii.  2nd Floor

cft

1000.60

220.30

220432.18

iv.  3rd Floor

cft

1000.60

223.80

223934.28

F.

Stair case, slab & steps etc.
Concrete
i.   Ground Floor

cft

60.92

220.00

13402.40

ii.  1st Floor

cft

60.92

223.50

13615.62

iii.  2nd Floor

cft

60.92

227.00

13828.84

iv.  3rd Floor

cft

60.92

230.50

14042.06

II

Steel works

a.

60 grade deformed
i.   Ground Floor

Qtl.

64.82

11371.00

737068.22

ii.  1st Floor

Qtl.

28.54

11396.00

325241.84

iii.  2nd Floor

Qtl.

28.54

11421.00

325955.34

iv.  3rd Floor

Qtl.

28.54

11446.00

326668.84

b.

40 grade deformed bar
i.   Ground Floor Slab

Qtl.

14.43

8699.00

125526.57

ii.  1st Floor  Slab

Qtl.

14.43

8724.00

125887.32

iii.  2nd Floor  Slab

Qtl.

14.43

8749.00

126248.07

iv.  3rd Floor Slab

Qtl.

14.43

8774.00

126608.82

Grand Total (I+II)

TK

               39,59,720.16

 Cost analysis of volume of concrete & steel for Type-II structure:

This cost analyses, shown in Table 7.2, are completed according to “schedule of rate for civil works”, 12th edition, Public Works Department.

Table 7.2: Cost Analysis of volume of concrete & steel for Type-II structure

Sl. No.

Short Description

Unit

Total

Rate in Taka

Amount in Taka

I

Concrete works

 

 

 

 

A.

Foundation (Footing)
Concrete

cft

1021.83

213.30

217956.34

B.

Grade beam
Concrete

cft

300.49

213.30

64,094.52

C.

Pedestal column, column.
Concrete
i.   Below PL level

cft

61.29

215.80

38,071.44

ii.   Ground Floor

cft

109.69

219.30

24,055.02

iii.  1st Floor

cft

109.69

222.80

24,351.18

iv.  2nd Floor

cft

109.69

226.30

24,822.85

v.  3rd Floor

cft

109.69

229.80

25,119.01

D.

Beam:
Concrete
i.   Ground Floor

cft

494.47

213.30

1,05,470.45

ii.  1st Floor

cft

494.47

216.80

1,07,201.10

iii.  2nd Floor

cft

494.47

220.30

1,08,931.74

iv.  3rd Floor

cft

494.47

223.80

1,10,662.38

E.

Roof slab etc.
Concrete
i.   Ground Floor

cft

1159.17

213.30

2,47,250.96

ii.  1st Floor

cft

1159.17

216.80

2,51,308.06

iii.  2nd Floor

cft

1159.17

220.30

2,55,305.00

iv.  3rd Floor

cft

1159.17

223.80

2,59,422.24

F.

Stair case, slab & steps etc.
Concrete
i.   Ground Floor

cft

62.93

220.00

13,734.60

ii.  1st Floor

cft

62.93

223.50

13,953.10

iii.  2nd Floor

cft

62.93

227.00

14,171.61

iv.  3rd Floor

cft

62.93

230.50

14,390.11

II

Steel works

a.

60 grade deformed
i.   Ground Floor

Qtl.

54.91

11371.00

624381.61

ii.  1st Floor

Qtl.

22.95

11396.00

2,61,538.20

iii.  2nd Floor

Qtl.

22.95

11421.00

2,62,111.95
iv.  3rd Floor

Qtl.

22.95

11446.00

2,62,685.70

b.

40 grade deformed bar
i.   Ground Floor Slab

Qtl.

34.59

8699.00

3,00,898.41

ii.  1st Floor  Slab

Qtl.

34.59

8724.00

3,01,763.16

iii.  2nd Floor  Slab

Qtl.

34.59

8749.00

3,02,627.91

iv.  3rd Floor Slab

Qtl.

34.59

8774.00

3,03,492.66

Grand Total (I +II)

TK.

                 4539831.31

CHAPTER IX 

CONCLUSIONS & RECOMMENDATIONS

 Recommendations:

Based on the objectives, scopes and limitations of the study (stated in Chapter I) as well as discussions and conclusions that made on the obtained results, few recommendations can be proposed for further studies:

  • This study was conducted for beam supported slab only. Other types of slab (such as flat or flat slab etc.) may be considered.
  • ACI Moment Coefficient procedure was followed during analysis and design of slabs. Any other procedure (such as Direct Design or Equivalent Frame Method etc.) can be followed for comparison.
  • Structural analysis software can be used.
  • This study was conducted based on low rise concept, further analyses considering high rise design criteria can be performed.
  • Same study can be conducted considering commercial buildings instead of residential one.

 Conclusions:

After performing estimation, cost analyses and comparison for the specified four storied residential structure as well as discussions made earlier chapters, following information are obtained:

  • The total volume of Concrete required in Type-II is 1.11 times higher than Type-I structure.
  • The total volume of Steel (60 grade) required in Type-II is 1.24 times lower than Type-I structure.
  • The total volume of Steel (40 grade) required in Type-II is 2.40 times higher than Type-I structure.
  • The total costing for concrete and steel works required in Type-II is 1.15 times higher than Type-I structure.

Thesis Paper On Longer Span Floor Beams System Of Edge Supported Structures(part 1)

Thesis Paper On Longer Span Floor Beams System Of Edge Supported Structures(part 2)

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