My Section size is 175 x 8 Flange and 1000 x 10 Web of Fy= 345 Mpa.
The unsupported length about x and y is 1.5m. Lz is 25m.
Capacity as per STAAD is 953.62 kNm doesnt match with manual value.
But STAAD Output report, the value is 953.623 kNm which is laterally supported beam capacity as per Cl 8.2.1.2. Is this issue with Current update 6?
Please find the Manual Calculation for the beam considered for design. I had used IS 800: 2007
formula for Mcr calculation. Eventhough with formula mentioned in STAAD Example, there is a meagre variation in Mcr value.
Please find the STAAD Editor attached below. Beam ID Considered for design is 9
I run the file in below mentioned version.
STAAD.Pro CONNECT Edition * * Version 22.06.00.138
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STAAD SPACESTART JOB INFORMATIONENGINEER DATE 30-Jul-21END JOB INFORMATIONINPUT WIDTH 79UNIT METER KNJOINT COORDINATES5 0 10 0; 6 25 10 0; 7 0 24 0; 8 25 24 0; 9 50 10 0; 10 50 24 0; 11 75 10 0;12 75 24 0; 13 100 10 0; 14 100 24 0;MEMBER INCIDENCES7 5 7; 8 6 8; 9 7 8; 10 9 10; 11 8 10; 12 11 12; 13 10 12; 14 13 14; 15 12 14;DEFINE MATERIAL STARTISOTROPIC STEELE 2.1e+08POISSON 0.3DENSITY 76.8195ALPHA 1.2e-05DAMP 0.03G 7.88462e+07TYPE STEELSTRENGTH RY 1.5 RT 1.2END DEFINE MATERIALMEMBER PROPERTY9 11 13 15 TAPERED 1.016 0.01 1.016 0.175 0.0087 8 10 12 14 TAPERED 0.95 0.012 0.95 0.5 0.025CONSTANTSBETA 90 MEMB 7 8 10 12 14MATERIAL STEEL ALLSUPPORTS5 6 9 11 13 FIXED BUT MZLOAD 1 LOADTYPE None TITLE DLSELFWEIGHT Y -1 MEMBER LOAD9 11 13 15 UNI GY -1.6LOAD 2 LOADTYPE None TITLE COLLMEMBER LOAD9 11 13 15 UNI GY -5.69 11 13 15 UNI GY -8LOAD 3 LOADTYPE None TITLE LIVEMEMBER LOAD9 11 13 15 UNI GY -6LOAD COMB 4 COMBINATION LOAD CASE 41 1.5 2 1.5 3 1.5 PERFORM ANALYSIS PRINT ALLLOAD LIST 4PARAMETER 1CODE IS800 LSDBEAM 1 ALLFYLD 345000 ALLFU 450000 ALLLAT 0 MEMB 9 11 13 15LX 1.5 MEMB 9 11 13 15LY 1.5 MEMB 9 11 13 15MAIN 180 ALLSTP 2 ALLTRACK 2 ALLCHECK CODE ALLFINISH
Please calculate Mcr with this equation
Here is the calculation for major axis bending capacity (Member 15)
In the value of Design Lambda Lt= Sqrt(1.2 Zez*fy/Mcr) = 0.611 in my calculation.
But while using Zey in above formula, instead of Zez we are able to get the value of 0.1017 which is less than 0.4, which eliminates LTb clause check.
Is using Zey in the formula while calculating major axis moment capacity is correct?
In the example attached in STAAD Help,
They are using Zez only.
Please refer the below example. There also they are referring Zez while calculating major axis moment capacity.
communities.bentley.com/.../80730
I apologies, I have done one mistake in the calculation, please allow me some time to check
Hi,
We rechecked our calculations, there is a clause in IS 800:2007 given below.
As per the Cl 8.2.1.1 a, We got bending moment capacity about major axis considering flanges alone as 439.1 kNm. On checking the same model with Update 2, the moment capacity is 438.7 kNm but in update 6 the moment capacity is 953.6 kNm. Please clarify.
Further, the shear capacity along minor axis as per manual calculation is 507 kN but as per Update 6 & Update 2, it is 258.5 kN.
Please Clarify Bending capacity and Minor axis shear capacity.