Project Job Ref.

REV.LAW RENCE AND MRS THERESA ETTU PROJECT 07

HAMZ CONZULT
15 kagha street Section Sheet no./rev.
PANEL 13 1
Calc. by Date Chk'd by Date App'd by Date
AMADI 3/5/2016 ENGR. ETTU ENGR

RC SLAB DESIGN (BS8110:PART1:1997)

TEDDS calculation version 1.0.03

TWO WAY SPANNING SLAB DEFINITION - RESTRAINED

; Overall depth of slab; h = 150 mm
Outer sagging steel
; Cover to outer tension reinforcement resisting sagging; c sag = 25 mm
; Trial bar diameter; D tryx = 12 mm
Depth to outer tension steel (resisting sagging)
d x = h - c sag - D tryx/2 = 119 mm
Inner sagging steel
; Trial bar diameter; D tryy = 12 mm
Depth to inner tension steel (resisting sagging)
d y = h - c sag - D tryx - D tryy/2 = 107 mm
Outer hogging steel
; Cover to outer tension reinforcement resisting hogging; c hog = 25 mm
; Trial bar diameter; D tryxhog = 12 mm
Depth to outer tension steel (resisting hogging)
d xhog = h - c hog - D tryxhog /2 = 119 mm
Inner hogging steel
; Trial bar diameter; D tryyhog = 12 mm
Depth to inner tension steel (resisting hogging)
d yhog = h - c hog - D tryxhog - D tryyhog /2 = 107 mm
Materials
; Characteristic strength of reinforcement; fy = 410 N/mm 2
; Characteristic strength of concrete; f cu = 25 N/mm 2

Asyhog N om inal 1 m w idth Asxhog

h dx
h dxhog

Asy Nom inal 1 m w idth Asx

Shorter Span

Asyhog Asxhog

h dy
h dyhog

Asy (sagging m om ents) Asx (hogging m om ents)

Longer Span

Two-way spanning slab

(restrained)
 Project Job Ref.
REV.LAW RENCE AND MRS THERESA ETTU PROJECT 07
HAMZ CONZULT
15 kagha street Section Sheet no./rev.
PANEL 13 2
Calc. by Date Chk'd by Date App'd by Date
AMADI 3/5/2016 ENGR. ETTU ENGR

RESTRAINED 2 WAY SPANNING (CL 3.5.3)

MAXIMUM DESIGN MOMENTS

; Length of shorter side of slab; lx = 3.185 m
; Length of longer side of slab; ly = 6.675 m
; Design ultimate load per unit area; n s = 13.0 kN/m 2

; Edge condition shorter side (1); Edge 1 = "C"

; Edge condition other shorter side (2); Edge 2 = "C"
; Edge condition longer side (3); Edge 3 = "C"
; Edge condition other longer side (4); Edge 4 = "C"
Number of discontinuous edges
Nd = 0
Moment coefficients
sy = (24 + 2N d + 1.5N d2 ) / 1000 =0.024
1 = if(Edge 1 == "C", 4/3 sy,0) = 0.032
2 = if(Edge 2 == "C", 4/3 sy,0) = 0.032

= 2/9 [3 - (18) lx /ly (( sy + 1) + ( sy + 2 ))] = 0.454

3x = if(Edge 3 == "C", 4/3,0) = 1.333
4x = if(Edge 4 == "C", 4/3,0) = 1.333
sx = / [(1+ 3x )0.5 + (1+ 4x) 0.5 ]2 = 0.049
3 = 3x sx = 0.065
4 = 4x sx = 0.065

Maximum span moments per unit width - restrained slabs

m sx = sx n s l x2 = 6.4 kNm/m
m sy = sy n s l x2 =3.2 kNm/m
Maximum support moments per unit width - restrained slabs
m sxhog = max( 3 , 4 ) n s lx2 = 8.5 kNm/m
m syhog = max( 1 , 2 ) n s lx2 =4.2 kNm/m

CONCRETE SLAB DESIGN SAGGING OUTER LAYER OF STEEL (CL 3.5.4)

; Design sagging moment (per m width of slab); m sx = 6.4 kNm/m
; Moment Redistribution Factor; bx = 1.0
Area of reinforcement required
;; K x = abs(m sx) / ( d x 2 f cu ) = 0.018
K'x = min (0.156 , (0.402 ( bx - 0.4)) - (0.18 ( bx - 0.4) 2 )) = 0.156
Outer compression steel not required to resist sagging
Slab requiring outer tension steel only - bars (sagging)
 Project Job Ref.
REV.LAW RENCE AND MRS THERESA ETTU PROJECT 07
HAMZ CONZULT
15 kagha street Section Sheet no./rev.
PANEL 13 3
Calc. by Date Chk'd by Date App'd by Date
AMADI 3/5/2016 ENGR. ETTU ENGR

;; z x = min (( 0.95 d x ),(d x (0.5+0.25-K x /0.9)))) = 113 mm

Neutral axis depth; xx = (d x - z x ) / 0.45 = 13 mm
Area of tension steel required
;;; A sx_req = abs(m sx ) / (1/ ms fy z x ) = 159 mm 2/m
Tension steel
;;Provide 12 dia bars @ 150 centres; outer tension steel resisting sagging
A sx_prov = A sx = 754 mm 2 /m
Area of outer tension steel provided sufficient to resist sagging

Concrete Slab Design - Sagging - Inner layer of steel (cl. 3.5.4)

; Design sagging moment (per m width of slab); m sy = 3.2 kNm/m
; Moment Redistribution Factor; by = 1.0
Area of reinforcement required
;; K y = abs(m sy) / ( d y2 fcu ) = 0.011
K'y = min (0.156 , (0.402 ( by - 0.4)) - (0.18 ( by - 0.4)2 )) = 0.156
Inner compression
steel not required to
resist sagging
Slab requiring inner tension steel only - bars (sagging)
;; z y = min (( 0.95 d y),(d y(0.5+0.25-K y/0.9)))) = 102 mm
Neutral axis depth; xy = (d y - z y) / 0.45 = 12 mm
Area of tension steel required
;;; A sy_req = abs(m sy) / (1/ms fy z y) = 87 mm 2 /m
Tension steel
;;Provide 12 dia bars @ 150 centres; inner tension steel resisting sagging
A sy_prov = A sy = 754 mm 2 /m
Area of inner tension steel provided sufficient to resist sagging

CONCRETE SLAB DESIGN HOGGING OUTER LAYER OF STEEL (CL 3.5.4)

; Design hogging moment (per m width of slab); m sxhog = 8.5 kNm/m
; Moment Redistribution Factor; bx = 1.0
Area of reinforcement required
;; K xhog = abs(m sxhog ) / ( d xhog 2 fcu ) = 0.024
K'x = min (0.156 , (0.402 ( bx - 0.4)) - (0.18 ( bx - 0.4) 2 )) = 0.156
Outer compression steel not required to resist hogging
Slab requiring outer tension steel only - bars (hogging)
;; z xhog = min (( 0.95 d xhog ),(d xhog (0.5+0.25-K xhog /0.9)))) = 113 mm
Neutral axis depth; xxhog = (d xhog - z xhog ) / 0.45 = 13 mm
Area of tension steel required
;;; A sxhog_req = abs(m sxhog) / (1/ ms f y z xhog ) = 212 mm 2 /m
Tension steel
;;Provide 12 dia bars @ 200 centres; outer tension steel resisting hogging
 Project Job Ref.
REV.LAW RENCE AND MRS THERESA ETTU PROJECT 07
HAMZ CONZULT
15 kagha street Section Sheet no./rev.
PANEL 13 4
Calc. by Date Chk'd by Date App'd by Date
AMADI 3/5/2016 ENGR. ETTU ENGR

A sxhog_prov = A sxhog = 565 mm 2/m

Area of outer tension steel provided sufficient to resist hogging

Concrete Slab Design - hogging - Inner layer of steel (cl. 3.5.4)

; Design hogging moment (per m width of slab); m syhog = 4.2 kNm/m
; Moment Redistribution Factor; by = 1.0
Area of reinforcement required
;; K yhog = abs(m syhog ) / ( d yhog 2 fcu ) = 0.015
K'y = min (0.156 , (0.402 ( by - 0.4)) - (0.18 ( by - 0.4)2 )) = 0.156
Inner compression
steel not required to
resist hogging
Slab requiring inner tension steel only - bars (hogging)
;; z yhog = min (( 0.95 d yhog ),(d yhog (0.5+0.25-K yhog /0.9)))) = 102 mm
Neutral axis depth; xyhog = (d yhog - z yhog ) / 0.45 = 12 mm
Area of tension steel required
;;; A syhog_req = abs(m syhog ) / (1/ ms f y z yhog ) = 116 mm 2 /m
Tension steel
;;Provide 12 dia bars @ 200 centres; inner tension steel resisting hogging
A syhog_prov = A syhog = 565 mm 2/m
Area of inner tension steel provided sufficient to resist hogging
Check min and max areas of steel resisting sagging
;Total area of concrete; A c = h = 150000 mm 2/m
; Minimum % reinforcement; k = 0.13 %
A st_min = k A c = 195 mm 2 /m
A st_max = 4 % A c = 6000 mm 2 /m
Steel defined:
; Outer steel resisting sagging; A sx_prov = 754 mm 2 /m
Area of outer steel provided (sagging) OK
2
; Inner steel resisting sagging; A sy_prov = 754 mm /m
Area of inner steel provided (sagging) OK
Check min and max areas of steel resisting hogging
;Total area of concrete; A c = h = 150000 mm 2/m
; Minimum % reinforcement; k = 0.13 %
A st_min = k A c = 195 mm 2 /m
A st_max = 4 % A c = 6000 mm 2 /m
Steel defined:
; Outer steel resisting hogging; A sxhog_prov = 565 mm 2 /m
Area of outer steel provided (hogging) OK
2
; Inner steel resisting hogging ; A syhog_prov = 565 mm /m
Area of inner steel provided (hogging) OK
 Project Job Ref.
REV.LAW RENCE AND MRS THERESA ETTU PROJECT 07
HAMZ CONZULT
15 kagha street Section Sheet no./rev.
PANEL 13 5
Calc. by Date Chk'd by Date App'd by Date
AMADI 3/5/2016 ENGR. ETTU ENGR

CONCRETE SLAB DEFLECTION CHECK (CL 3.5.7)

; Slab span length; lx = 3.185 m
; Design ultimate moment in shorter span per m width; m sx = 6 kNm/m
; Depth to outer tension steel; d x = 119 mm
Tension steel
; Area of outer tension reinforcement provided; A sx_prov = 754 mm 2 /m
; Area of tension reinforcement required; A sx_req = 159 mm 2 /m
; Moment Redistribution Factor; bx = 1.00
Modification Factors
;Basic span / effective depth ratio (Table 3.9); ratio span_depth = 20
The modification factor for spans in excess of 10m (ref. cl 3.4.6.4) has not been included.
;fs = 2 fy A sx_req / (3 A sx_prov bx ) = 57.7 N/mm 2
factortens = min ( 2 , 0.55 + ( 477 N/mm 2 - fs ) / ( 120 ( 0.9 N/mm 2 + m sx / d x 2 ))) = 2.000
Calculate Maximum Span
This is a simplified approach and further attention should be given where special circumstances exist. Refer to clauses
3.4.6.4 and 3.4.6.7.
Maximum span; l max = ratio span_depth factor tens d x = 4.76 m
Check the actual beam span
Actual span/depth ratio; l x / d x = 26.76
Span depth limit; ratio span_depth factor tens = 40.00
Span/Depth ratio check satisfied

CHECK OF NOMINAL COVER (SAGGING) (BS8110:PT 1, TABLE 3.4)

; Slab thickness; h = 150 mm
; Effective depth to bottom outer tension reinforcement; d x = 119.0 mm

; Diameter of tension reinforcement; D x = 12 mm

; Diameter of links; L diax = 0 mm
Cover to outer tension reinforcement
c tenx = h - d x - D x / 2 = 25.0 mm
Nominal cover to links steel
c nomx = c tenx - L diax = 25.0 mm
Permissable minimum nominal cover to all reinforcement (Table 3.4)
; c min = 25 mm
Cover over steel resisting sagging OK

CHECK OF NOMINAL COVER (HOGGING) (BS8110:PT 1, TABLE 3.4)

; Slab thickness; h = 150 mm
; Effective depth to bottom outer tension reinforcement; d xhog = 119.0 mm
 Project Job Ref.
REV.LAW RENCE AND MRS THERESA ETTU PROJECT 07
HAMZ CONZULT
15 kagha street Section Sheet no./rev.
PANEL 13 6
Calc. by Date Chk'd by Date App'd by Date
AMADI 3/5/2016 ENGR. ETTU ENGR

; Diameter of tension reinforcement; D xhog = 12 mm

; Diameter of links; L diaxhog = 0 mm
Cover to outer tension reinforcement
c tenxhog = h - d xhog - D xhog / 2 = 25.0 mm
Nominal cover to links steel
c nomxhog = c tenxhog - L diaxhog = 25.0 mm
Permissable minimum nominal cover to all reinforcement (Table 3.4)
; c min = 25 mm
Cover OK over steel resisting hogging
;