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(b)<br />
Use of the Tables:<br />
Strength Limit State - Select a section with the least mass from the Tables such that the maximum design<br />
loads W * L1 and W * L2 are greater than or equal to W L . It can be seen from Table D8.1-1(2)(A) that for a 100<br />
x 50 x 2.5 DuraGal RHS Grade C450L0, the maximum design loads are:<br />
W * L1 = 18.4 kN<br />
W * L2 = 220 kN<br />
∴ W * L = 18.4 kN (> 15.5 kN)<br />
Therefore, a 100 x 50 x 2.5 DuraGal RHS has adequate strength.<br />
Serviceability Limit State - From Table D8.1-1(1)(B) it can be seen that for a 150 x 50 x 2.5 DuraGal RHS<br />
Grade C450L0, the serviceability load is:<br />
W * S = 9.76 kN<br />
(> 8.90 kN)<br />
The most efficient and practical hollow <strong>sections</strong> for this application are RHS and SHS. The alternative<br />
<strong>sections</strong> which satisfy the above strength and serviceability limit states are listed below:<br />
150 x 50 x 2.5 DuraGal RHS Grade C450L0 mass per metre = 7.53 kg/m<br />
125 x 75 x 3.0 DuraGal RHS Grade C450L0 mass per metre = 8.96 kg/m<br />
100 x 100 x 5.0 DuraGal SHS Grade C450L0 mass per metre = 14.2kg/m<br />
Therefore, based on mass, select 150 x 50 x 2.5 DuraGal RHS Grade C450L0.<br />
2. A beam which is simply supported has a span of 6.0 metres with full lateral restraint. The beam is<br />
subjected to nominal central dead and short term live loads of 1.0 kN and 2.5 kN respectively.<br />
Design a suitable DuraGal RHS in Grade C450L0 steel with no limit on deflection.<br />
Solution:<br />
(i) Calculate equivalent uniformly distributed maximum design load for moment (W * EM )<br />
From Table D8.5 (W * EM ) associated with the central dead and live loads is:<br />
W * EM<br />
= 2P<br />
= 2 (1.25 x 1.0 + 1.5 x 2.5)<br />
= 10 kN<br />
(ii) Based on W * EM select the least mass section with an adequate maximum design load (W * L1 )<br />
based on design moment capacity.<br />
From Table D8.1-1(1)(A), a 100 x 50 x 2.5 DuraGal RHS Grade C450L0 has adequate<br />
maximum design load (W * L1 = 12.2 kN).<br />
(iii) Calculate equivalent uniformly distributed maximum design load for shear (W * EV ).<br />
From Table D8.5 the equivalent uniform moment load is:<br />
W * EV<br />
= P<br />
= 1.25 x 1.0 + 1.5 x 2.5<br />
= 5.0 kN<br />
DuraGal DESIGN CAPACITY TABLES<br />
DCTDHS/06<br />
D8-8 for STRUCTURAL STEEL HOLLOW SECTIONS MARCH 2002
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