Consulting Structural
Engineers
Splice Connection Design
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Structural calculations for steel beam splice connection design
We provide steel beam splices calculations to BS5950 or Eurocode 3 design codes, ensuring your splice connection complies with Building Regulation standards.
Our structural engineers will design your splice connection to suit your exact beam size and loading requirements and provide design calculations that are accepted by Building Control departments nationwide.
Fast service and detailed output
We supply as standard detailed connection drawings and installation instructions so fabricators know exactly what to make and installers know exactly how the connection should be fitted.
Our fast online service ensures a quick turnaround helping you to avoid delays and keep your project on schedule. You can also contact us for a quote.
Fast service and detailed output
We supply as standard detailed connection drawings and installation instructions so fabricators know exactly what to make and installers know exactly how the connection should be fitted.
Our fast online service ensures a quick turnaround helping you to avoid delays and keep your project on schedule. You can also contact us for a quote.
Why use a bolted splice connection?
Bolted splice connections are the quickest and easiest way for steel beams to be joined on site in a quality assured manner and avoid the fire risk and quality control difficulties of on-site welding.
Reducing long beams into shorter and more manageable sections is often necessary for ease of transport, safe handling or to facilitate installation, particularly when installing steelwork in loft conversions and existing buildings.
Which splice connection type?
A bolted splice connection can be formed using 'cover plate' splices or bolted 'end plate' splices (see images). Both are designed to transmit bending moment and shear forces across the joint, allowing a spliced beam to behave as a continuous member and each have their pros and cons - see box below for more technical information.
The size and thickness of steel plates, grade, diameter and quantity of bolts and weld specification (where relevant) vary depending on beam size and applied loads so it's important splices are designed to suit each application.
Cover Plate Splice Connection
End Plate Splice Connection
Hollobolt® Splice Connection
Splice Connection Technical Information:
Cover plate vs. End Plate splice:
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Cover plate splice connections typically allow a stronger and more rigid connection than end plate splices.
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End plate splice connections have the advantage of avoiding protruding plates and bolt heads, but are less rigid and cannot achieve the higher bending moment resistance of a cover plate splice.
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Typically end plate splices are less suited to beams that are not laterally restrained as they can reduce the minor axis stiffness of a beam and therefore reduce it's lateral torsional buckling capacity.
Splice Location
Splices are usually located at 1/3rd span to avoids sections of the beam experiencing high shear force (span ends) or high bending moments (mid-span). Splicing at mid-span should be avoided. The total number of splices in a beam should be kept to a minimum as each splice has the potential to increase deflection.
Bolts (Ordinary vs Pre-load/HSFG)
The tolerance gap around bolts when using standard size bolt holes in a cover plate splice connection can lead to unwanted joint slip and beam deflection. Preload bolts (often referred to as HSFG or 'High Srength Friction Grip bolts) are usually used to mitigate this. Fitting preload bolts is not complex, however there are specific installation details that should be followed, including the use of the correct bolts and nuts, hardened washers and direct tension indicating' (DTI) washers to ensure correct critical bolt tightness is achieved. Our splice designs include full guidance on bolt type and installation.
End plate splices will typically use standard structural (non-preload) bolts.
Splice limitations
There are limits to what bolted splices can achieve. In high load cases it may be necessary to increase the beam weight or size to make splicing feasible.
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'Full strength' bolted splices are typically not practical and, in reality, very rarely needed.
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Symmetrical 'open' sections (meaning I section beams) are preferred for splicing.
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Whilst channel (PFC) sections can be spliced, their asymmetry makes this inefficient and it is recommend to change to a symmetrical beam section if it has to be spliced (we can advise on this).
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Hollow tube sections (RHS (rectangular), SHS (square), CHS (circular) can be spliced, but be aware such splices require bulky flanges or specialised Hollo-Bolt® arrangements.