Building regs.

[enyam]

Hi all,I've obtained building regs to knock down a couple of load bearing walls architect and structual engineer involved,but with a caveat added that they want more info regarding load bearing A,I'll add the drawings to show what I have.
The council and the engineer seem to be at odds and I'm in the middle.
Any thoughts?

Steel beams supporting new external wall to kitchen—maximum span = 3.60m

Same Loadings:
Beam ‘A’ - Section size: 2No. 203x133x30 UB Grade 43 – Maximum span 3.60m PL and UDL Load D= 206.8mm B=133.9mm t=6.4mm T=9.6mm Ix=2,900cm4 ry=3.17cm Zx=280cm3 Le/ry = 3.20x100.00/3.17 = 123 D/T = 21.50
Permissible bending stress pbc = 138.5N/mm2 (Table 3a) Actual bending stress fbc = 30.15 x 1000/280.0 = 107.7N/mm2 Therefore OK.
Maximum shear = 24.50x1000/(6.4x206.8) = 18.52N/mm2 Therefore OK.

Check unstiffened web capacity with load of 34.15 Bearing Pb = 210N/mm2 (Table 9) C1 = 40.0KN; C2 = 1.34KN/mm Buckling Pc – 146N/mm2 (Table 17a) C1 = 96.6KN; C2 = 0.934kN/mm R1 unstiffened web capacity, Pw = 33.2KN – no stiffening required R2 unstiffened web capacity, Pw = 33.2KN – no stiffening required

Total deflection = 28.3x1e8/205,000x2,900 = 4.8mm (L/631) Therefore OK.
Combined bearing and shear check (14.c): (fbc/ pbc) 2 + (fs/ps)2 = 0.605 at 2.00m Less than 1.25 = Therefore OK

Bearing details: 100mm end bearing with steels built into blockwork at both ends R1 (17.50KN unfactored): 15mm mild steel bearing plate, size 250x100mm = 1.18N/mm2

Steelwork bearing to garage – 600mmx100mmx420mm C30 concrete padstone

Beams to be bolted together ay 600mm centres

Beam ’B’ into garage—Section size: 2No. 178x102x19 UB grade 43 – Maximum span of 2.2m Maximum bending moment = 1.10metres from R1 Maximum SF = 33.39 at R1 Total deflection = 14.8x1e8/EI at 1.10 from R1 (E in N/mm2, 1 in cm4)

Steel calculation to BS449 Part 2 using S275 (Grade 43) steel UDL Loading only D= 177.8mm B=101.2mm t=4.8mm T=7.9mm Ix=1356cm4 ry=2.70cm Zx=153cm3 Le/ry = 3.40x100.00/2.70 = 126 D/T = 37.04 Permissible bending stress pbc = 130.1N/mm2 (Table 3a) Actual bending stress fbc = 10.49 x 1000/153.0 = 68.56/mm2 Therefore OK.
Maximum shear = 16.21x1000/(4.8x177.8) = 18.99N/mm2 Therefore OK.
R1 (17.50KN unfactored): 15mm ms bearing plate, size 250x100mm = 1.18N/mm2 R2 (17.50KN unfactored): Bolted to main steel above .

 

[John D v2.0]

Ask them what details they need and ask the se to provide them. Better still get the se to talk directly to the bco, but it depends what your contact with them says

 

[enyam]

Ask them what details they need and ask the se to provide them. Better still get the se to talk directly to the bco, but it depends what your contact with them says

Thanks for the reply all the caveat said was they want more details of adequate bearing of beam a in 2 storey section of dwelling,the council are mixed up here I think because above the beam is just the upstairs so only one storey,I'm trying to upload the drawing.Trouble is its got my name and address on it.

 

[enyam]

Here is the drawing.

 

[^woody^]

If you've paid an engineer, a proper engineer, then he should be debating things with the council inspector. Typically, an inspector can't argue with an engineer because the inspector is not qualified to do so. But, there is always the chance that the engineer is crap.

Your calculations are meaningless here and none can verify them.

 

[tony1851]

Looking at the beam layout, I would say the beam section sizes and padstones are perfectly OK. There are no loads specified, but if it's a normal two-storey house, those beams will be OK.
There may be a fiddly detail to connect the secondary beams to the main beam, unless one set is supported on top of the other

 

[Notch7]

The structural engineer I use, notes on his calcs that they should be accepted by the BCO and any queries should be referred back to him.

The SE's design will be underwritten by his PI insurance, so its important you interpret the spec correctly to be covered. The BCO may query the calcs but he has no jurisdiction other than confirm the SE is compliant.

Your drawing could do with clarification what the end bearing plates are and how the smaller steels connect to the main ones. Generally Ive found the SE specifies cleats which have 2 pairs of holes for bolts.. A cleat is a short section of angle iron, say 150 x 150 x 10 150mm long. In other words a super heavy duty angle bracket.

 

[enyam]

Thanks all,I'll get back to you when I hear anything.

 

[tony1851]

Your drawing could do with clarification what the end bearing plates are and how the smaller steels connect to the main ones. Generally Ive found the SE specifies cleats which have 2 pairs of holes for bolts.. A cleat is a short section of angle iron, say 150 x 150 x 10 150mm long. In other words a super heavy duty angle bracket.

How would an angle work, given that the clear depth between the flanges of the main beam would be less than the depth of the incoming beams?
If the bearing of the incoming beams was offset from the web of the main beam, the latter would need to be checked for torsion.