Analysis of an Overlapping Bolted Connection of Steel Sheets with High Strength Bolts

Objective: Check the mode for calculating bolted connections

Task: Check an overlapping connection of 300х14 mm sheets with high strength bolts from steel grade С275 for a shear force.

Source: Moskalev N.S., Pronosin J.A. Steel Structures. Handbook / M.: ASV Publishing House, 2010. p. 101.

Compliance with the codes: SNiP II-23-81*, SP 16.13330, DBN B.2.6-163:2010.

Initial data file:

2.6.sav;
report — Kristall2.6.doc

Initial data:

N = 800 kN	Shear force;
Rbh = 945 MPa	Bolts from steel grade 30H3MF; Diameter of bolts 20 mm, diameter of holes 23 mm;
γc = 1; γb = 0,9	Service factors;
μ = 0,35	Method of cleaning the surfaces – steel brush;
γh = 1,06	Tightening control – by the nut rotation angle.

 

KRISTALL parameters:
Steel: C275

Importance factor	1
Service factor	1
Service factor  of members to be joined	1

Diameter of bolts 20 mm
Steel: 30H3MF
Clearance 3 mm
Method of cleaning the surfaces to be joined: Steel brush, two surfaces without preservation

Type:	Parameters:
	m = 1 n = 2 a = 60 mm b = 90 mm c = 30 mm t = 8 mm t0 = 14 mm

 

Internal forces and moments:

N = 800 kN
M = 0 kNm
Q = 0 kN

Manual calculation:

1. Design tension resistance of high strength bolts was calculated according to the following formula:

\[ R_{bh} =0,7R_{bun} =0,7\times 1350=945 \quad Н/мм^{2}=94,5 \quad kN/cm^{2}. \]

2. Design force which can be resisted by each plane of friction:

\[ Q_{bh} =\frac { R_{bh} A_{bn} \mu} {\gamma_{h} }=\frac {94,5\times 2,45\times0,35}{1,06}=76,447 \quad kN, \]

3. Required number of bolts:

\[ n\ge \frac{N}{Q_{bh} \kappa \gamma_{b} \gamma_{c} }=\frac{800}{76,447\times 2\times 0,9\times 1,0}=5,814. \]

Comparison of solutions:

Factor	Manual calculation	KRISTALL	Deviation from the manual calculation, %
Friction force limit	5,814/6 = 0,969	0,969	0,0