For example, if you are using the beam to span above bi-fold doors you may need to set a lower limit, or if the beam is going to be used as a structural ridge beam the variable load deflection should not normally exceed 10mm.Ħ.2) Total Variable and Permanent Load Deflection Limit Normally this is restricted to span/360, however there are exceptions. Limits, but you may need to change these. Our Calculator defaults to the recommended Limit for how much it can sag under Variable Loads – usually things that canĬhange, such as people or furniture – and under Permanent Loads, such as the The distribution of bending moments along the length of the beam affects it buckling capacity, C1 is a factor for the shape of the bending moment between points of lateral restraint, for a beam with only uniformly distributed loads along its full length C1 can be taken as 1.13, for more information see SCI Publication P360.Ī Deflection Limit is the maximum amount you allow the beam to sag. This is the most conservative, safe value and is recommended for general use. Recommended value from EN 1990:2002+A1 Eurocode – Basis of structural design (UK National annex) is 1.35 and our Calculator defaults to this. In the calculations all the permanent loads are multiplied by this safety factor to ensure a safe design. Permanent loads (also known as dead loads) are usually things that do not change, such as the weight of the floor or a wall. Recommended value from EN 1990:2002+A1 Eurocode – Basis of structural design (UK National annex) is 1.5 and our Calculator defaults to this. In the calculations all the imposed loads are multiplied by this safety factor to ensure a safe design. Imposed loads (also known as live loads) are usually things that can change, such as people or furniture. You can also enter a buckling length, for example where the ends of the beams are not fully restrained you can input a buckling length that is greater than the effective span, for more information on buckling lengths please refer to SCI Publication P360. If there is more than one restraint, you will need to add these as well. In this case, you should measure the dimension between the lateral restraint and the beam end and enter this dimension. If the beam is restrained at points along its length, for example where another beam is fixed at right angles to the beam along its length. If your beam is not going to be fully restrained and the beam is only restrained at its supports, you can select, ‘Unrestrained – the beam is only restrained at its support’. If you need to know more, please call 01332 410066 for help. It is only classedĪs fully restrained if it meets the requirements stated in SCI Publication P360, an exampleīeing where a steel beam is cast into a concrete floor. If you need to work out the point load from a beam which is going to be supported by another beam, please see our How to design a beam which is required to support another beam guide.Ĥ.1) You need to know if the beam is going to be Fully Restrained along its length. If the load on your beam is a Point Load, you will need to enter the dimension between the Point Load and the end of the beam, as well as its Permanent and Variable load. You do not need to add the weight of the steel beam itself, our calculator automatically does this. We also have a list of Standard permanent loadsįor commonly used items, such as clay tiles and rafters. "Sloping roof with an angle of up to 30 degrees or timber floor in a domestic dwelling" and then enter the Width or Height of the load (use "other" if you can't see an option that describes the nature of your load.)įor details on how to calculate the load widths, see our Examples Page and Diagrams showing how to calculate load widths. If you choose one of these types, you can select the Loading Details from the Dropdown Menu (e.g. Point Load is where there are localised loads at certain points along the beam.ģ.1) Uniformly Distributed Loads and Partial Uniformly Distributed Loads.Partial Uniformly Distributed Load is where the load is evenly distributed across part of the beam.Uniformly Distributed Load is where the load is evenly distributed across the full length of the beam.You need to know what type of load your beam will be supporting.
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