7.1 Tension members: Single angles
The value of tension capacity Pt is given generally by equivalent tension area x py :
4.6.3.1
(i) For bolted sections,
Pt = (Ae – 0.5a2)py
(ii) For welded sections,
Pt = (Ag – 0.3a2)py
where:
4.6.1/3.4.3
| Ae |
is the effective net area of the angle |
| Ag |
is the gross area of the angle |
| py |
is the design strength of the angle |
| a2 |
is defined below. |
Note: A block shear check (BS 5959-1: 2000, Clause 6.2.4 and Figure 22) is also required for tension members. However, 'block shear' capacities have not been tabulated, as there are too many variables in the possible bolt arrangements.
4.6.1/3.4.3
The effective net area of the section Ae is given by:
| For bolted sections, |
Ae = ae1 + ae2 |
but |
≤ 1.2(an1 + an2) |
3.4.3
where:
| ae1 |
= Ke an1 |
but ≤ a1 |
| ae2 |
= Ke an2 |
but ≤ a2 |
| an1 |
= a1 – area of bolt holes in connected leg |
| an2 |
= a2 |
| Ag |
= Gross area of single angle |
| Ke |
= 1.2 for grade S275 |
| |
= 1.1 for grade S355 |
| a1 |
= Gross area of connected leg |
| |
= A x t |
if long leg connected |
| |
= B x t |
if short leg connected |
4.6.3.1
7.2 Compound tension members: Two angles
The values of tension capacity are based on the effective net area of the section, calculated as for single angles in Section 7.1.
The value of tension capacity Pt is given generally by equivalent tension area x py :
4.6.3.2 (a)
4.6.3.2 (b)
(i) For bolted sections,
| Pt = 2(Ae – 0.25a2)py |
For a gusset between the angles |
| Pt = 2(Ae – 0.5a2)py |
For a gusset on the back of the angles |
4.6.3.2 (a)
4.6.3.2 (b)
(ii) For welded sections,
| Pt = 2(Ag – 0.15a2)py |
For a gusset between the angles |
| Pt = 2(Ag – 0.3a2)py |
For a gusset on the back of the angles |
Symbols as defined in Section 7.1.
Note: A block shear check (BS 5950-1: 2000, Clause 6.2.4 and Figure 22) is also required for tension members. However, 'block shear' capacities have not been tabulated as there are too many variables in the possible bolt arrangements.
