PROJECT: DUBAI MALL FASHION AVENUE EXTENSION

LOCATION: DUBAI, UAE

SUBJECT: GRC SCREEN

I

FIG. 1 ELEVATION

FIG. 2 SECTION FIG. 3 FRONT VIEW

2024 mm

1680

3236

II GIVEN DATA

GRC UNIT WEIGHT = 2000 kg/m

MODULUS OF ELASTICITY (E) = 6895 MPa

FOR THE SCREEN

GRC THICKNESS = 35 mm

LENGTH = 2024 mm

WIND PRESSURE = Wp = 2.19 kPa

TRIBUTARY AREA = 1680x 2024= 3400320 mm

3.400 m

LESS AREA OF OPENINGS = 2094411 mm

2.094 m

NET EFFECTIVE AREA Ag = 1.306 m

NET AREA FACTOR = 1.31/3.40 0.384

FOR THE SECTION OF THE SCREEN

two size of the screen section

N. Axis35 35

N. Axis

c = 18.33

ave b = 35 ave b = 25

see at section bb

COMPUTE THE M.I. (I) OF SECTION

Width of the panel = 1300 mm

Effective width after reduction of the openings

= 806 mm

Effective moment of Inertia

= 806 x 353

12

= 2,879,771 mm4

35 35

Wp = -3.16 kPa

-3160 Pa Trib. B = 1.68 M

Effective wind pressure = Wp x Net area factor

= 3.16 x 0.384

= -1.214 kPa

Wind load per unit length = -2.04

= 2.04 kN/m

ASSUME AS A BEAM

2024

V = w L/2 2064.48 N

192560

M =wL 835,701.5 M = wL

10 10

max M = 835,702 N-mm

BENDING

fb = M c

I

835701.504 x 18.33

2,879,771

fb = 5.32 N/mm

FOR ALLOWABLE BENDING STRESS OR FLEXURAL = 900 psi

6.2 N/mm

fb IS LESS THAN ALLOWABLE, HENCE OK

SHEAR

fv = V

A

fv = 2064.48 A = (35 x 35)x2 + (25 x 35) x 7

8575 8575 mm

fv = 0.241 N/mm OK

FOR ALLOWABLE SHEAR STRESS= 400 Psi

2.758 N/mm

fv IS LESS THAN ALLOWABLE, HENCE OK

DEFLECTION

Max. Deflection = wl4

384 EI

= 4.49 mm

Allowable Deflection = span/200

= 10.12 mm

Maximum deflection is less than allowable. HENCE OK

CHECK FOR THE MIDDLE SUPPORT STEEL BRACKET

TRIBUTARY AREA = 1520 x 976

AT = 1483520 mm

LESS OPENINGS = 851224

Ag = 632296 mm

WT. = 720 N

COMPUTE FOR THE WEIGHT OF THE SCREEN AND BORDER AS PER TRIBUTARY AREA

SCREEN : BORDER

VOL = Ag x THK VOL = Ag x HEIGHT BUT Ag = 50x95x2

632296 x 35 9500 x 1520 9500

22130360 mm 14440000 mm

0.02213036 m 0.01444 m

TOT VOL= 0.03657036 M

WEIGHT OF GRC = VOLUME x UNIT WEIGHT

0.03657036 x 2000

WT. = 73.14072 kg x 9.81

717.51 N

say WT. = 720 N

CHECK FOR THE SHEAR ON THE BOLT

fv = P USE 10 mm BOLT

A A = 78.54 mm

720

78.54

fv = 9.17 N/mm OK

ALLOWABLE Fv = 0.4Fy = 0.4(275)= 110 N/mm SAFE

CHECK FOR THE BENDING ON THE ANGLE ( 50x50x6mm )

M

FOR THE SECTION OF ANGLE 50x50x6mm A1

y1 Y

a1 y2

a2

COMPUTE FOR THE CENTROID

A1 = 50 x 6 = 300 mm A2

A2 = 44 x 6 = 264 mm

Atot = 564 mm

y1 = 3 mm a1= Y- y1= 11.70

y2 = 28 mm a2= y2- Y= 13.30

BY AREA MOMENT METHOD

Atot ( Y ) = A1y1 + A2y2

564 Y = 300(3) + 264(28)

Y = 14.70

COMPUTE FOR THE I(MOMENT OF INERTIA)

I = bh + Aa

12

I1 = 50 (6) + 300(11.7)

12

I1 = 41981.93753 mm4

I2 = 6 (44) + 264(13.3)

12

89276.01992 mm4

I total = 131257.9574 mm4

FOR BENDING

fb = M c WHERE :

I M = 720(139)

100080 x 14.7 100080 N-mm

131257.9574 c = Y = 14.70 mm

fb = 11.21 N/mm OK

ALLOW. Fb = 0.66 Fy = 0.66(275) = 181.5 N/mm

FOR DEFLECTION

def = P L WHERE :def = P L WHERE :

3 E I P = WT. = 720 N

L = 139 mm

720( 139) E = 200000 N/mm

3(200000) 131258

def = 0.025 mm OK, LESS THAN THE ALLOWABLE. SAFE!

ALLOW DEFLECTION = L / 240 = 0.58 mm

NOTE : FOR THE OTHER STEEL BRACKET SUPPORT, USE THE PREVIOUS DESIGN :