written 5.8 years ago by |
and embedded in concrete of 200mm thick RCC skab. The parapet wall of 230mm thickness and 1.2m in height is provided on all peripheral beams
used calculation
For given Slab pane
ly/lex=5/3=1.666$\lt$ 2
hence is it is two way slab
The load is transfer as shown in fig
dead load+live load
self weight is Rcc slab=0.15$\times$25=375kbN/m$^{2}$
uve load=4kn/m$^{2}$
Total floor load=7.75kn/m$^{2}$
Tributary area of slab to transfer load =1/2$\times4\times$=10m$^{2}$
floor load on beam B$_{3}$ per m run
=$\frac{7.75\times 10}{5}$=15.5mm
load of brick wall perm run =0.15$\times3.50\times$20=10.5kN/m
Total load per m run on Beam B$_{3}$
15.5+15.5=26kN/m
Assuming self weight of beam=$\frac{Total \ imposed \ load}{300}=\frac{26 \times 4.6}{3.20}$ =0.398 say 0.75$\times $ kN/m
self weight =0.75kN/m
Total working load in Beam B$_{3}$=28+0.75=26.75kN/m
wl/2=66.875
VB=66.875kN
loading on B1
point load on the center of beam AB=66..875km end reaction of beam B1 wall load on Beam B1=10.5kN/m
Total imposed load w=66.825+(10.5$\times$5)=119.325 kN
self weight =$\frac{115.375\times 1}{300}$=0.397 say 0.75kN/m
Total load on Beam B$_{1}$=10..5+0.75=11.25kN
loading on B1 as shown
max Bm=m=$\frac{66.875\times 5}{2}+\frac{11.25\times 5^{2}}{8}$=202.33kN.m
factored shear force Vd=1.5$\times 61.562=$92.343kN
Factored BbM=Md=1.5$\times 202.33$=303.495 kN.m
Assuming plastic section
(Zp)req=Md/fy/$\gamma$ ms=$\frac{303.495}{250/1.1}$=1.33
(Zp)req=1.32
(Ze)req=$\frac{1.33\times 1000}{1.14}$=1.166m$^{3}$
section ISLB 450
check for shear Vdr=$\frac{fy\times tw\times g}{\gamma mo\times \sqrt{3}}$=$\frac{250\times8.6\times 450}{1.1 \times \sqrt{3}}$=507.80kM $\gt$ Vd also Vd/Vdr $\lt$ 0.6 =0.18$\lt$0.6
sallwable =L/300=500/300=16.66mm
$\int$max=$\frac{5wl^{4}}{384 eI}=\frac{5\times 7.75\times 5000^{4}}{384\times 2\times 10^{5}\times275.36\times 10^{6}}$
$\int$max=11.45 mm
AS $\int$ max $\lt \int allowable$