We need to use a universal column to support RSJ spanning 4.9 clear span. With the universal column in the centre of the span, should the RSJ be long enough to cover the whole length or shorter ones be used, joined at the universal column.
Universal columns
- Thread starter DIYDavies
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Hi,
If I am reading your post correctly you have a 4.9m span RSJ and will be supporting it in the middle by a column, thus creating two spans of 2.45m.
This being the case it would be cheaper to use a 4.9m span RSJ and then support this on a column with a cap plate to the top of the column but this means you have to man handle a 4.9m long RSJ. The easier to install option would be to use two RSJ's each of which has a connection into the side of the column. This would cost a little more though as most of the cost of steelwork is in fabricating the connections (two sections could also be supported on a column cap plate as well but the cap would need to be bigger).
Either way, you will need a Structural Engineer to design the RSJ's, column and connections for you.
I hope this helps you.
If I am reading your post correctly you have a 4.9m span RSJ and will be supporting it in the middle by a column, thus creating two spans of 2.45m.
This being the case it would be cheaper to use a 4.9m span RSJ and then support this on a column with a cap plate to the top of the column but this means you have to man handle a 4.9m long RSJ. The easier to install option would be to use two RSJ's each of which has a connection into the side of the column. This would cost a little more though as most of the cost of steelwork is in fabricating the connections (two sections could also be supported on a column cap plate as well but the cap would need to be bigger).
Either way, you will need a Structural Engineer to design the RSJ's, column and connections for you.
I hope this helps you.
Thank you so much for replying, as we have to order the steel in a few days. We understand that we need an engineer and are in the process of obtaining this advice
We are not worried about the cost or handling issue, we just want the best method of spanning the 4.9 metres and want to know if the universal column should be placed in the centre of an RSJ, putting a stress on the steel that could deflect movement to the ends of the RSJ. A relative has told us that RSJs should have the stress on the ends and that is why it is better to use two shorter ones and even better to rest the ends of them on a centre brick pier.
We are also aware that we will need two RSJs side by side, one for the inner blocks and outer blocks.
It's great to have a forum like this so that expert opinions can be sought once again many thanks for your reply
We are not worried about the cost or handling issue, we just want the best method of spanning the 4.9 metres and want to know if the universal column should be placed in the centre of an RSJ, putting a stress on the steel that could deflect movement to the ends of the RSJ. A relative has told us that RSJs should have the stress on the ends and that is why it is better to use two shorter ones and even better to rest the ends of them on a centre brick pier.
We are also aware that we will need two RSJs side by side, one for the inner blocks and outer blocks.
It's great to have a forum like this so that expert opinions can be sought once again many thanks for your reply
By the way it is the wife of the DIYer writing this blog, so sorry about the lack of technical vocabulary!
Just worried about the house falling down once the extension is built!
Just worried about the house falling down once the extension is built!
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All I can advise is what I would do. If it were me I would use one long piece of steel if it is possible to do so. The reason for this is that a continuous steel beam will in theory reduce the reactions slightly to the outer ends of the beam (presumably bearing on padstones on the masonry) and also the theoretical deflections of the beam will be reduced. This is because a continuous beam is less able to rotate at the column compared to formed connections, even if the rotations expected are very small.
In reality, either method is perfectly acceptable and will not change the beam size required.
One other thing. Being you mentioned a cavity wall and so I assume it is an external wall. The load in each leaf is likely to be different and so make sure the beams are sized accordingly to make the deflections of each similar. If the beams end up different sizes due to this it may very well be the shorter beams is the better option (connections into side of column) . Either way is can be difficult since the column is unlikely to be the same width as the wall (wall 300mm width, columns 150/200mm?). It may be better to use a universal beam section instead to give extra depth required. Some engineers will place a steel plate on top of the steel beam pair of the same size to try and share the load between the two.
I hope this helps!
In reality, either method is perfectly acceptable and will not change the beam size required.
One other thing. Being you mentioned a cavity wall and so I assume it is an external wall. The load in each leaf is likely to be different and so make sure the beams are sized accordingly to make the deflections of each similar. If the beams end up different sizes due to this it may very well be the shorter beams is the better option (connections into side of column) . Either way is can be difficult since the column is unlikely to be the same width as the wall (wall 300mm width, columns 150/200mm?). It may be better to use a universal beam section instead to give extra depth required. Some engineers will place a steel plate on top of the steel beam pair of the same size to try and share the load between the two.
I hope this helps!
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