Civil Engineering - RCC Structures Design - Discussion
Discussion Forum : RCC Structures Design - Section 4 (Q.No. 41)
41.
For M 150 grade concrete (1:2:4) the moment of resistance factor is
Discussion:
23 comments Page 2 of 3.
Tirupathi said:
7 years ago
M/I=f/y=E/R.
Use M/I=f/y.
M=f/y*I.
f=15.
I=a4/12 (bd3/12) here b&d both are same b&d=a.
Y bcz cube is square.
y=a/2.
As per standard dimension of the concrete cube for testing, compression is 150mm=a.
M=15*150*150*150*150*2/12*150=8.4375=8.5
Consider fck is 15 full strength.
Use M/I=f/y.
M=f/y*I.
f=15.
I=a4/12 (bd3/12) here b&d both are same b&d=a.
Y bcz cube is square.
y=a/2.
As per standard dimension of the concrete cube for testing, compression is 150mm=a.
M=15*150*150*150*150*2/12*150=8.4375=8.5
Consider fck is 15 full strength.
Pawan said:
6 years ago
Thanks @Tirupathi.
Sandip das said:
6 years ago
As per IS code 456- 2000 R is the moment of the resistance factor, does not depend on dimensions, it's called design constant, the value of R for M15;
1. mild steel =0.867.
2. Fe 415=0.65.
3. Fe 500=0.58.
1. mild steel =0.867.
2. Fe 415=0.65.
3. Fe 500=0.58.
Vishal said:
6 years ago
0.87 is the correct answer.
(1)
Jayaraj said:
6 years ago
Mur = Q.bd^2
= 0.148 fck bd^2. For Fe250
Q = 0.148x15 = 2.22.
Why this is not correct?
= 0.148 fck bd^2. For Fe250
Q = 0.148x15 = 2.22.
Why this is not correct?
Sushil Jaiswal said:
5 years ago
No, it is not right because MOR factor can get only SP-16 graph which is given in IS456:1998 and value is in table 70 (8.5 N/sqm).
Sachin Singh said:
5 years ago
WSM mtd Mr = Qbd2.
M150 Xc= 0.39d, z=0.87d.
MOR = bx sigma z/2 = b* 0.39d* 50* .87d/2.
MOR= 8.5bd2.
σ = 50 kg/cm2.
M150 Xc= 0.39d, z=0.87d.
MOR = bx sigma z/2 = b* 0.39d* 50* .87d/2.
MOR= 8.5bd2.
σ = 50 kg/cm2.
Raihan said:
5 years ago
0.87 is the correct answer.
(2)
Jay said:
4 years ago
0.7 X √(150) = 8.57.
(1)
Vinod kumar yadav said:
4 years ago
Resistance factor = 0.7 * √(fck).
0.7 * √{150) = 8.5.
0.7 * √{150) = 8.5.
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