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Steel Staircase Design

This document summarizes the design checks performed for a 250x75x25 lipped channel and 50x50-3mm thick square hollow section. Key checks included: - Verifying the bending moment, shear force, and deflection of the lipped channel meet requirements. - Checking the plastic shear and bending resistances of the 50x50 SHS are adequate for the calculated design loads. - Designing the bolt connection between the 50x50 SHS and a 38x63x4.5mm steel plate to resist the bending moment at the support. The connection was found to be adequate.

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Senthooran Mahendran
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614 views4 pages

Steel Staircase Design

This document summarizes the design checks performed for a 250x75x25 lipped channel and 50x50-3mm thick square hollow section. Key checks included: - Verifying the bending moment, shear force, and deflection of the lipped channel meet requirements. - Checking the plastic shear and bending resistances of the 50x50 SHS are adequate for the calculated design loads. - Designing the bolt connection between the 50x50 SHS and a 38x63x4.5mm steel plate to resist the bending moment at the support. The connection was found to be adequate.

Uploaded by

Senthooran Mahendran
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as XLSX, PDF, TXT or read online on Scribd
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REFERENCE DESCRIPTION REMARKS

DESIGN CHECK OF 250X75X25, 4.5mm THICK LIPPED CHANNEL

Dead load acting on lipped channel = 25x0.05x.25 = 0.32kNm


Design Dead load = 1.35x0.32 = 0.43kNm

SS EN 1991-1-
1-1 :2008 Imposed load acting on lipped channel = 4kN
Design Imposed load = 1.5x6 = 6kN
Design BM =
BM due to Dead load= PL2/8 = .14 kNm 2.54kNm
BM due to Imposed load = PL/4 = 2.4 kNm
Total bending moment = 2.54 kNm Design SF = 2.26kN

SHEAR RESISTANCE

6.2.6 (VEd/Vc,Rd) < 1.0

Vc,Rd = (Av(Fy/30.5)/M0
Av = 2x55x4.5 = 495mm2
Vc,Rd = (495x275/1.732)/1.0 = 78.59kN
Shear resistance is
(VEd/Vc,Rd) = 2.26/78.59 = 0.03 < 1.0 adequate

6.2.5 MOMENT RESISTANCE

(MEd/Mc,Rd) < 1.0


Mc,Rd = (Wpl,y *fy)/M0 = 23200x275/1.0Nmm = 6.38 kNm
Design moment resistance for class-4 member = 2.6kNm
REFERENCE DESCRIPTION REMARKS

Moment resistance
is adequate
MEd/Mc,Rd = 2.54/2.6 = 0.98 <1

VERTICAL DEFLECTION

w = (FL3)/(48EI)
w = (FL3)/(48EI) = (4x16003)/(48x210x126000)
w = 12.9 mm

Vertical deflection
span/120 = 1600/120 = 13.33mm > 12.9mm is acceptable

DESIGN OF 50x50-3mm THICK SQUARE HOLLOW SECTION

Horizontal SHS span L=1m


Vertical SHS length = 0.6m

HORIZONTAL SHS DESIGN


LOAD COMBINATION (ULS)
1.35gk +1.5 qk = 1.35x1.25 + 1.5x3 = 6.19 kN/m2
Fd = 6.19x0.8 = 4.95kN/m

DESIGN MOMENT AND SHEAR FORCE Max BM at


MY.Ed=(FdL2)/8 = 4.95x12/8 = 0.62kNm Mid Span
0.62 kNm

VEd = FdL/2 = 4.95x1/2 = 2.5kN Max SF =


2.5 kN

BS EN 1993-1- Plastic shear resistance Vpl,Rd= Av(fy/3 )/M0


.5

1 : 2005, 6.2.6
Av = Ah/(b+h) = 541x50/100 = 270mm 2
Vpl,Rd= 270(275/1.732)/1.0 = 42870N = 42.8kN
Vpl,Rd > VEd
Hence okay

BENDING RESISTANCE

BS EN 1993-1-
1 : 2005, 6.2.5 Mpl,Rd = Wplfy/M0
REFERENCE DESCRIPTION REMARKS
Mpl,Rd = 7790x275/1.0x10-6 = 2.14kNm
Mpl,Rd > My,Ed

VERTICAL SHS DESIGN


LOAD COMBINATION (ULS)
Design BM =
BM due to Dead load= PL2/12 = .1 kNm 1.3 kNm
BM due to Imposed load = PL/8 = 1.2 kNm
Total bending moment = 1.3 kNm Design SF = 2.26kN

BS EN 1993-1- Plastic shear resistance Vpl,Rd= Av(fy/3.5)/M0


1 : 2005, 6.2.6
Av = Ah/(b+h) = 541x50/100 = 270mm 2
Vpl,Rd= 270(275/1.732)/1.0 = 42870N = 42.8kN
Vpl,Rd > VEd
Hence okay

BENDING RESISTANCE
BS EN 1993-1-
1 : 2005, 6.2.5 Mpl,Rd = Wplfy/M0
Mpl,Rd = 7790x275/1.0x10-6 = 2.14kNm
Mpl,Rd > My,Ed

50X50-3mm SHS - FLOOR CONNECTION DESIGN


38X63X4.5mm Steel plate will be welded to the SHS

BM at the support = 1.3kNm

BOLT DETAILS
BS EN 1993 Tensile stress area of bolt = 36.6 mm 2
-1-8 : 2005 Diameter of holes = 10mm
Diameter of washer = 16mm
Yield strength = 680N/mm2
Ultimate strength = 800N/mm2

BS EN 1993 End distance = 1.2x10 = 12 mm


-1-8 : 2005
Table 3.3
REFERENCE DESCRIPTION REMARKS

BS EN 1993 BOLTS IN SHEAR


-1-8 : 2005 Fv,Rd = vfubA/M2
3.6.1 Fv,Rd =0.8x0.6x800x36.6x10-3/1.25 = 11.2 kN
Fv,Rd = 25.8 kN

BS EN 1993 PLATE IN BEARING


-1-8 : 2005 Fb,Rd = K1bfu,pdtp/M2
3.6.1 b = min(d;fu,b/fu,p;1.0) = min(38/(10x3) ; 800/430 ; 1.0)
b = 1
K1 = min (2.8e2/d - 1.7 ; 2.5) = (2.8x38/10-1.7 ; 2.5) = (8.94;2.5)
K1 = 2.5
Fb,Rd = 2.5x1x430x8x4.5/1.25 = 30.96 kN

TENSION ON BOLT
Therefore the
Tension force acting on bolt = 1.3 / (0.0315/2) = 20.64kN connection is able
20.64kN< 21.08 kN to take the design
load

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