Gantry crane (single and double girder, rail-mounted)

01

Size rated load, span, lifting height and duty group

OSHA's overhead and gantry crane rule (29 CFR 1910.179) defines a gantry crane as similar to an overhead crane except that the bridge carrying the trolley is rigidly supported on two or more legs running on fixed rails or other runway; a cantilever gantry crane has girders that extend beyond the runway on one or both sides. It defines span as the horizontal distance centre to centre of runway rails, and rated load as the maximum load the crane or hoist is designed and built for by the manufacturer and shown on its nameplate. [1]

Dafang lists double girder gantry cranes with capacities up to 800 t, spans up to 100 m, cantilevers of 5–15 m, duty groups A3–A7 and a working environment of −25 °C to +50 °C at up to 95% relative humidity, for indoor and outdoor use. It describes four support legs joining the main beam to ground beams, adding travel bogies to reduce wheel load when capacity or span is large, and truss-type girders for open areas with strong wind. Its single girder gantry cranes reach 50 t and 50 m span. [2]

Editorial note: give the supplier your expected lifts per hour and typical load against rated load, not only the maximum load, so that the duty group quoted can be checked against your use.

Weihua's brochure for its A-type double girder gantry crane of 5–50 t, of the European-standard type, describes box girders with the trolley rail offset over one web, a compact trolley with hard-tooth-face reducers, rolled pulleys and a welded drum, and travel drives using three-in-one geared motors with frequency control for smooth starting and braking. It lists 65Mn forged travel wheels for wear resistance and names lower self-weight and wheel load as aims, with anti-sway, vertical lifting, remote, and automatic or semi-automatic control as options. [3]

Editorial note: frequency-controlled travel and anti-sway are options in that range, not standard; if loads must be placed precisely or the crane runs long outdoor runways, list them in the enquiry and ask for the speeds and ramp times they give. [3]

Give the supplier the rated load and any second hoist, span and cantilevers, lifting height above and below rail, hook approach, travel length and rail details, speeds, duty group or load spectrum, indoor or outdoor use and design wind, power supply and feed method (cable reel, festoon, conductor), control (pendant, radio, cab), and the standard and inspection body required.

02

Specify wind protection, limit switches, brakes and load testing

Under 1910.179, outdoor storage bridges must have automatic rail clamps and a wind-indicating device that gives a visible or audible alarm to the bridge operator at a predetermined wind velocity; where clamps act on the rail heads, weld beads or flash must be ground off. The rated load must be plainly marked on each side of the crane, with each hoist's rating legible from the ground. [1]

The rule requires an overtravel limit switch in the hoisting direction on electric travelling cranes, defines bumpers as energy-absorbing devices at the end of travel and stops as travel-limiting devices, and requires hoist holding brakes of at least 125% of full-load hoisting torque with non-mechanical control braking, or 100% with mechanical control braking or for each of two brakes. Inspections are classed as frequent (daily to monthly) and periodic (1 to 12 months), and rated load test loads must not exceed 125% of rated load unless the manufacturer recommends otherwise, with reports kept on file. [1]

Dafang lists overload, travel and height limit switches and a hook safety latch as standard safety devices on its double girder gantry cranes. [2]

Editorial calculation: for a 20 t rated load (assumed), the OSHA ceiling for test load is 1.25 × 20 = 25 t; agree the actual test load, the procedure and who witnesses it before the crane ships.

UK law adds examination intervals that a gantry crane order should anticipate. Regulation 9 of the Lifting Operations and Lifting Equipment Regulations 1998 requires a thorough examination before lifting equipment is first put into service, unless it is new and comes with an EC declaration of conformity made not more than 12 months earlier; where safety depends on installation conditions, a thorough examination after installation and again after assembly at any new site or location. Equipment exposed to deterioration that could lead to danger must then be thoroughly examined at least every 12 months, or every 6 months for equipment that lifts persons and for lifting accessories, or under an examination scheme, and after any exceptional circumstances that could jeopardise its safety. Equipment may not leave one employer's undertaking, or be used in another's, without physical evidence of its last thorough examination. [4]

Editorial calculation: over a 10-year service period, a 12-month cycle means at least 10 periodic thorough examinations for the crane itself and at least 20 for each lifting accessory on a 6-month cycle, plus one after installation and one after each relocation where safety depends on installation conditions. [4]

03

Compare what suppliers offer

Suppliers linked to this page list gantry cranes; each card links to the page reviewed.

The suppliers reviewed list single and double girder, semi and European-style gantry cranes, and gantry crane parts; ask each for capacity, span and duty group, design wind speed, wheel loads and rail size, safety devices and the load test report.

04

Trace the crane components

This is a functional reference built from the sources cited; it is not one maker's design.

05

Fill the specification fields with values for your site

A gantry crane quotation needs values for your loads and site. The table explains each field, gives published values where a reviewed source states them, and says what to obtain from the supplier.

06

Send the load, span and site data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Load: [rated; second hoist; spectrum]
Geometry: [span; cantilevers; lifting height; travel]
Duty: [group; lifts per hour]
Site: [indoor or outdoor; design wind; temperature]
Rails: [rail; foundation; wheel load limit]
Power and control: [voltage; feed; pendant or radio]
Compliance: [standard; load test; inspection]

See manufacturer records Send an enquiry through CNFX