Overhead travelling cranes run at high level, most commonly 4,5 or 6 meters above ground. To support them and facilitate this, they need support steelwork or crane rails to run on. Crane steel work and rails, can come in various forms, here we will explain the most common used in the UK.
It can be a little daunting if you haven’t done this before, but we advise on the steel required everyday, and are here to help you.
The cheapest option is to support the horizontal crane running rails, via knee joints, on the building’s supporting uprights. This avoids you paying for columns as well, and labour to install them. You will need to ask yourself first and foremost, can the building structure support an overhead crane of the size and span you require? Also was the building designed to take a crane of the size you need? Buildings usually haven’t been designed with a crane in mind, as its cheaper that way. If this is the case then then free standing crane steelwork is for you.
Free Standing Crane Steelwork To British Standards and Eurocodes, EN 1090.
Correctly designed and calculated free standing gantry (FSG) crane steelwork is bolted directly onto the floor and is easily the most commonly used in the UK and across Europe. Most factories are built prior to the client moving in, or the crane being thought about. The builders will usually not include any calculations for the crane or its support steel work, only wind and snow loading to save money.
Bracing The Crane Steelwork. Portal, K-bracing or Tied Back Crane Steelwork.
Gantry cranes need support to stop them from the overturning moments imposed, or inertia when the hoist or crane travels.
The modern way, and our preferred method, is to brace the steel via portal columns. K-bracing can also be used or crane columns are sometimes tied into the buildings main frame, providing your structural engineer has agreed to it. The landlord may also have a say in this option.
In a portal bay we use 4 portal columns, 2 per side, facing each other. We situate these every 4 or 5 bays of free standing steel, often in the centre if the run of steel is 24 to 42 meters long. Usually a bay of support steel has a columns every 6 meters, but this can vary to suit your requirements. Longer bays, or pitches between supporting columns, help to miss obstructions in your workshop; such as fire doors.
Portal columns offer the least hindrance, and allow access under and through the crane supports, unlike K or X bracing’s. This allows fork lift trucks to pass between uprights unhindered, or exits, or work benches can be placed between the columns.
Crane K Bracing.
Some crane manufacturers still use K bracing, or X bracing, every few bays to limit movement or sway of a cranes structure. See below.
Tied Back Crane Columns.
The pictures below show an 8t SWL Demag crane tied to the building.
Crane Knee Joints, or Knee Brackets.
Knee joints are normally bolted to the building’s upright column portal frame. Please remember to leave enough room for the horizontal running rails, as well as the crane beam. We can advise on crane beam depths etc prior to an order being placed. More on gantry crane knee joints or track supports.
10 things to think about before ordering crane support steelwork.
- Can you attach the crane rails to the building frame.
- If free standing steel is required; how how deep is your concrete floor.
- What Safe Working Load crane do you require. How many kilos or tonnes will you be lifting.
- What span or width do you need the crane to be.
- What down shop length do you need, that is, how far do you want the crane to travel.
- If free standing steelwork is used is the floor strong enough to take the crane weight and the load added together, including the overturning moments/inertia imposed.
- What hook to floor height do you require.
- What height is the eaves at the lowest point.
- Will your landlord let you attach to the building.
- What pitches between columns do you need.
The part that goes wrong: Please note. If we are landing our crane onto your own rails, please remember the following:
- Ask your steel installation team to leave enough room for the horizontal down shop tracks as well as the crane beam.
- A minimum of 250mm should be left from the building upright to the centre line of the crane rails.
- Clients often think they have saved money only to find out their own steel erectors have “forgotten” to weld on the 50x50mm solid bar of S355 grade onto the tracks. Picture below.
- Lastly if you do the steel element yourself please ensure the span of the rails are parallel and within plus or minus 2mm.
If any of the above are not done correctly we will not be able to install your crane. if we supply the steel as well the above is our responsibility, why take the risk?
Ordering a crane and its support steel may seem daunting, but most of the questions above, we can help with on the telephone as we prepare your quotation. Exact measurements can be taken during a site survey if an order is placed. Our sales team are happy to help; please contact us here or telephone 01527 894 825 and ask to speak to a real person!
Overhead Traveling Cranes when traveling will create inertia that is imposed on the support steelworks. Inertia is the resistance of a physical object, to a change in its velocity, or speed. If you have received a quotation for a gantry crane and it does not include bracing of any sort be vary wary. If you would like to read about crane foundation bases, click here.