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Staircase Word Sheet

This document summarizes the design calculations for a staircase. It includes calculations to determine the total dead and imposed loads, bending moment, required reinforcement, and deflection check. The key details are a 4.735m span staircase with 1600mm width, 275mm treads and 150mm risers. The required main reinforcement is T12 bars at 150mm c/c providing 754mm2/m. Secondary reinforcement of T10 bars at 200mm c/c providing 393mm2/m is also specified.

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James Aswa
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325 views2 pages

Staircase Word Sheet

This document summarizes the design calculations for a staircase. It includes calculations to determine the total dead and imposed loads, bending moment, required reinforcement, and deflection check. The key details are a 4.735m span staircase with 1600mm width, 275mm treads and 150mm risers. The required main reinforcement is T12 bars at 150mm c/c providing 754mm2/m. Secondary reinforcement of T10 bars at 200mm c/c providing 393mm2/m is also specified.

Uploaded by

James Aswa
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 DOCX, PDF, TXT or read online on Scribd
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REF EC2 CALCULATIONS REMARKS

STAIRCASE DESIGN
Durability and fire resistance
Nominal cover for mild conditions of exposure = 25mm Cover = 25mm
1hrs fire resistance
Characteristic cube strength of concrete fck = 25N/mm2
Tensile strength of steel fyk = 500N/mm2
fyv = 250N/mm2
Unit weight of concrete = 25kN/m3
Considering;
L=4.735m
 Span =4735m
 Width, b = 1600m
 Treads = 275
 Risers=150mm
 Waist = 200mm

d’=169mm

Slope length of stairs = √(1.82+3.1252) = 3.61m

Considering 200mm thick waist; and 12mm bar diameter


effective depth, d=200-25-12/2 =169mm
Considering 1m width of the stair

Weight of waist plus steps


={(0.2×3.61)+(0.275×1.8/2)}×25 = 24.24kN/ m width Total dead load Gk
Weight of landing = 0.2x1.61x25 =8.05kN/m width
= 39.39kN/m
Finishes = 1.50 x4.735 = 7.10kN/m width
width.
TOTAL Gk =39.39kN/m width
Total impose load
Imposed load = 3 x 4.735 = 14.205kN/m width. Qk = 11.70kN/m
width.
Ultimate load, N =1.35gk+1.5qk

=1.35(39.39) + 1.5(14.205) F =74.48kN/m


width.
= 74.48kN/m width

Moment, M= Fl/10 = (74.48×4.735)/10,


M = 35.27kN.m/m

4
Considering monolithic construction; width

=35.27kN.m/m width
K =0.049
Design for mid span reinforcement
6
M 35.27 x 10
K= = =0.049
f ck bd 25 x 1000 x 1692
2

z
d [
= 0.5+ (√ 0.25− 1.134
K
)]≤ 0.95 Provide T12@
Lever arm, z = 0.95d
150c/c As
Area of reinforcement =754mm2/m.

M 35.27 x 106
As= =
0.87 f yk Z 0.87 x 500 x 0.95 x 169
= 505mm2/m
Minimum area of reinforcement = 0.13%bd
= 0.0013x1000x169 = 220mm2/m
Provide T12@ 150c/c As =754mm2/m > As min.

Deflection check
Span-effective depth ratio at the center of the span where the
moment is maximum,
100 Asreq 100 x 505
= =0.3>0.13
bd 1000 x 169
From table 6.10, and figure 6.3, the basic span-effective depth
ratio for a simply supported span with ρreq = 0.3% is 25.
Depth acceptable
Allowing for the actual steel area provided,
Limiting span-effective depth ratio = 25xAs,prov/As,req Provide
= 25x754/505 = 37.33 T10@300c/c
Actual span effective depth ratio = 4735/169 = 28.02

Secondary Reinforcement, ≥ 0.2As,min = 0.2x 754 =151mm2/m


Provide T10 @ 200c/c As = 393mm2/m

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