Eurocodes EC3 and EC5 compared with BS449, BS528 and BS5950
The following examples compare the load carrying capacities of various members when checked using SuperBeam (BS449/BS5268), ProSteel (BS5950) and EuroBeam (EC3/EC5). In each case member capacities are stated as dead+live, kN/m for beams and kN for columns. They have been calculated using equation 6.10b, i.e. factors of 1.25 (dead) and 1.5 (live), as against 1.4/1.6 in BS5950. With unrestrained steel beams, a C1 factor of 1.12 has been used.
In each case - glulam beams excepted - the highest member capacity is arrived at when using Eurocodes. Remember though - as David Brown of SCI has noted many times - that changing the code used does not make a member any stronger: what these figures show is that using Eurocodes allows higher loadings and/or the use of lighter sections by reducing what was presumably judged to be an unnecessarily high factor of safety.
|4m span restrained steel beam, 254x146x31 UB S275||15.8+15.8||18.0+18.0||19.6+19.6|
|Required S275 UB for load of 15.8+15.8||254x146x31||305x102x28||305x102x28|
|4m span unrestrained steel beam, 254x146x31 UB S275||9.4+9.4||10.1+10.1||14.4+14.4|
|4m span, lightest S275 UB for load of 9.4+9.4||254x146x31||254x146x31||203x133x30|
|5m span, lightest S275 UB for load of 20.0+20.0||457x191x67||356x171x67||406x178x54|
|Axially loaded steel column, 3m long, 152x152x23 UC S275||157.5+157.5||154.9+154.9||169.1+169.1|
|Cap connection column 5m long, bending about major axis, 203x133x25 UB S275||38.4+38.4||46.5+46.5||48.7+48.7|
|Solid C24 timber beam, 115x270, 5m span long term loading (bending)||8.5+8.5||N/A||10.5+10.5|
|C30 beam 115x270 as above||12.4+12.4||N/A||13.2+13.2|
|GL28c glulam beam 115x270 (6x45) as above||16.4+16.4||N/A||13.8+13.8|
|Note that when using BS5268, glulam is significantly stronger than solid timber; using EC5 the difference is minimal|
|GL28c glulam beam 115x450 (10x45) 8m span, otherwise as above||26.0+26.0||N/A||22.8+22.8|
E&OE: more examples to follow