ᐅ Structural calculations for wall openings: is the floor plan enough?
Created on: 25 Jan 2022 10:59
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Wilhelm2022
Hello everyone,
I would like to ask for your professional expertise regarding a structural question about my house. We want to remove a wall to create an opening. I have found an engineering firm that would calculate the structural requirements for me. However, the structural engineer said that the floor plan alone is sufficient to determine what kind of steel beam is needed. Is that possible? Isn’t it important to conduct an on-site inspection? Shouldn’t it be necessary to check the ceiling material and whether there are other walls above the one to be removed? I find it a bit strange that a simple floor plan, which is 50 years old, would be enough. I would appreciate your opinions. Thank you very much,
Wilhelm2022
I would like to ask for your professional expertise regarding a structural question about my house. We want to remove a wall to create an opening. I have found an engineering firm that would calculate the structural requirements for me. However, the structural engineer said that the floor plan alone is sufficient to determine what kind of steel beam is needed. Is that possible? Isn’t it important to conduct an on-site inspection? Shouldn’t it be necessary to check the ceiling material and whether there are other walls above the one to be removed? I find it a bit strange that a simple floor plan, which is 50 years old, would be enough. I would appreciate your opinions. Thank you very much,
Wilhelm2022
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Simon-18927 Jan 2022 13:44Hello,
regarding structural engineering, as a steel construction specialist, I can say that many safety factors must be considered. For example, there are bolted connections that are allowed to be loaded up to a maximum of 50%. The same applies to anchor checks. If an anchor is loaded over 90%, I choose the next larger size for my design. And why? During the shell construction phase, when the focus is primarily on structural integrity, it is still unknown what the client might do with the structure later on, such as making modifications or adding additional loads. The extra costs are minimal, while the increase in safety is significant.
Because the values used in structural calculations assume optimal conditions. Are these always present on site? Concrete without air or dirt inclusions, welds without slag inclusions and with optimal penetration depth...
As a tip, if the structural calculation specifies a profile, for example, HEA 240 with a width of 240mm (9.4 inches) and a height of 230mm (9.1 inches), and you find that profile too large as a single beam, the engineer can calculate two profiles placed side by side and bolted together. This might result in 2x HEA 140 profiles with a total width of 280mm (11 inches) but a height of only 133mm (5.2 inches). And just like that, you gain 100mm (4 inches) in height.
regarding structural engineering, as a steel construction specialist, I can say that many safety factors must be considered. For example, there are bolted connections that are allowed to be loaded up to a maximum of 50%. The same applies to anchor checks. If an anchor is loaded over 90%, I choose the next larger size for my design. And why? During the shell construction phase, when the focus is primarily on structural integrity, it is still unknown what the client might do with the structure later on, such as making modifications or adding additional loads. The extra costs are minimal, while the increase in safety is significant.
Because the values used in structural calculations assume optimal conditions. Are these always present on site? Concrete without air or dirt inclusions, welds without slag inclusions and with optimal penetration depth...
As a tip, if the structural calculation specifies a profile, for example, HEA 240 with a width of 240mm (9.4 inches) and a height of 230mm (9.1 inches), and you find that profile too large as a single beam, the engineer can calculate two profiles placed side by side and bolted together. This might result in 2x HEA 140 profiles with a total width of 280mm (11 inches) but a height of only 133mm (5.2 inches). And just like that, you gain 100mm (4 inches) in height.
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barfly66627 Jan 2022 13:55I would have the structural engineer come for an inspection before approving the construction work. It happened to me that the lintel was made with concrete (it was a fixed price, so the contractor tried to cut costs) and ended up being much too short (resting on half bricks) and undersized. Work was halted until the architect reviewed the situation. In the end, I had to have my contractor redo it with a steel beam at their own expense.
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Wilhelm20223 Feb 2022 15:15Hello everyone, thank you for your contributions. I have now received a calculation from the person who will also install the beam. He entered some data into a PC program (AEC software) and said he wants to install an HEB 140 beam. Actually, an HEB 120 would be sufficient, but he is choosing the larger one anyway. Unfortunately, I cannot understand these calculations at all. Could any of you professionals tell me if this makes sense, considering that the opening should be 2 meters (6.6 feet) wide and has to support a concrete ceiling? Could this be roughly correct? I’m really unsure… thanks and best regards
Do you have major concerns regarding the clearance height where a difference of 2-4cm (1-2 inches) would matter, or is there some flexibility?
A quick search for HEB beams shows a price difference of about €50 for a 3m (10 ft) length (HEB120 €175, HEB140 €220). I would only invest more time and discussion if those few centimeters make a significant difference.
A quick search for HEB beams shows a price difference of about €50 for a 3m (10 ft) length (HEB120 €175, HEB140 €220). I would only invest more time and discussion if those few centimeters make a significant difference.
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taschenonkel9 Feb 2022 19:50Don’t worry as long as there is no multi-story high-rise building resting on the HEB 140. It will hold. Such a steel beam is extremely strong. As long as you don’t create an opening 5m (16.4 ft) wide, the 140 beam will usually be sufficient. Even then, it would be enough with an additional support...
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Wilhelm202213 Feb 2022 01:16Sorry for my late reply. Thanks to all of you anyway. No, it doesn’t matter if it’s off by 2–4 cm (1–1.5 inches).
The breakthrough will be made next week; I’m curious to see if everything works out.
Have a great weekend,
Best regards
The breakthrough will be made next week; I’m curious to see if everything works out.
Have a great weekend,
Best regards
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