BMG Semi Gantry Crane

The BMG semi gantry crane is a double-girder gantry crane that mounts one end on an existing building column and runs the other on a ground rail, handling 5–320 tons across spans of 6–24 m. It suits heavy machinery manufacturing, steel service centres, and automotive component plants. Each unit carries CE certification under Machinery Directive 2006/42/EC and conforms to ISO 9001:2015.

What Is a Semi Gantry Crane?

A semi gantry crane uses one rigid leg on a ground-level rail and one end beam riding on an existing building column or wall bracket, supporting spans from 6 to 24 m without the full portal structure a standard gantry crane requires. As a result, civil foundation costs drop substantially compared to a conventional double-leg portal design.

The BMG model from Dafang uses a double-girder box-section main beam, engineered under FEM 1.001 (European Crane Classification Standard) and GB/T 14406, and verified by finite element analysis (FEA) to keep deflection within L/1000 under full rated load. The BMG series of gantry cranes are for work duty classes A5, A6 and A7, covering intermittent to intensive production cycles. Every unit ships with full documentation for CE and ISO compliance, which many procurement teams require before sign-off.

BMG Semi Gantry Cranes — Configuration Variants

Three span and duty configurations cover the majority of industrial applications:

Configuration	Span Range	Lifting Capacity	Duty Class	Typical Use Case
Standard BMG Gantry Crane	6–16 m	5–50 t	A5	Light manufacturing, warehousing
Medium-Duty BMG Gantry Crane	12–20 m	20–160 t	A5/A6	Steel fabrication, press shops
Heavy-Duty BMG Gantry Crane	16–24 m	80–320 t	A6/A7	Shipbuilding, heavy forgings

All configurations use an electric trolley hoisting mechanism. Control method and hook height are configurable per project.

What Are Engineering Features of BMG Gantry Cranes?

Six design decisions define the BMG crane's performance in demanding production environments:

• Double-girder box-section beams — fabricated from Q355B high-tensile structural steel (GB/T 1591), shot-blasted and epoxy-primed for corrosion resistance; service life exceeds 20 years under A5/A6 duty.
• FEA-verified structural integrity — deflection held within L/1000 per ISO 4301 structural class at 100% rated load; no derating required for span extremes.
• Inverter-controlled electric trolley — smooth start/stop at 1–10 m/min lift speed; bridge travel at 35–40 m/min with precise positioning to ±10 mm.
• Asymmetric leg design — one rigid ground leg, one building-mounted end beam; saves floor area and reduces civil works to a single ground rail foundation.
• Work duty classes A5, A6, and A7 — each class calibrated to daily operating hours and load spectrum per ISO 4301; correct class selection extends major component intervals.
• IP54 electrical enclosures — dust-tight and splash-proof as standard; suitable for outdoor and semi-open environments without additional weatherproofing.

Which Industry Do BMG Gantry Cranes Applied For?

The BMG semi gantry crane performs reliably across six industrial sectors:

• Heavy machinery manufacturing — assembly of press frames, machine tool structures, and fabricated steel components; A5/A6 duty handles single lifts to 160 t.
• Steel service centres — coil and plate handling with magnetic or C-hook attachments; continuous-cycle requirement makes A6 the standard specification.
• Automotive component plants — stamping die changes, body-in-white fixture transfer, and sub-assembly movement along production lines.
• Precast concrete yards — lifting of beams, columns, and bridge segments in open-air or semi-enclosed environments; hot-dip galvanised members resist weathering.
• Rail freight terminals — loading and unloading of out-of-gauge cargo; rubber-tired ground travel option available for ballast-free rail yard surfaces.
• Shipbuilding workshops — hull section transfer and equipment installation in dry docks; heavy-duty A7 specification supports round-the-clock production cycles.

Indicative Scenario

A steel fabrication workshop with a 22 m clear span, 7 m-centred existing columns, and a 50 t plate-lifting requirement specifies a 20 m span BMG crane, A6 duty class, with cab control. The single-sided ground rail reduces foundation concrete by approximately 40% versus a full portal design — a standard business case outcome.(Representative configuration, not a verified customer case.)

Technical Parameters

Mode	BMG Semi Gantry Crane
Parameter	Specification
Load Capacity	5-320 ton
Span	6-24 meter
Max. Lifting Height	20 meter
Lifting mechanism	Electric Trolley
Lifting speed	1-10 m/min
Traveling Speed	35-40 m/min
Work Duty	A5, A6, A7  (per ISO 4301)
Control Method	Ground Pendant / Wireless Control / Operator Cab
Power Source	3-Phase 380V 50hz / Customizable
Structural Steel	Q355B (GB/T 1591) — box-section double girder
Surface Treatment	Shot-blast SA 2.5 + Epoxy primer + Topcoat
Electrical Protection	IP54 standard; IP65 available on request
Certification	CE (Machinery Directive 2006/42/EC) / ISO 9001:2015

Note: Lifting capacity, span, lifting height, duty class, and power supply are all configurable. Contact Dafang engineering for non-standard spans, lifting heights, or work duty requirements beyond A7.

Compliance & Quality Assurance

Every BMG semi gantry crane ships with a complete compliance documentation package. Applicable standards include:

• CE Declaration of Conformity — Machinery Directive 2006/42/EC
• ISO 9001:2015 — Quality Management System
• FEM 1.001 — European Standard for Crane Classification and Design
• GB/T 14406 — Chinese National Standard for General-Purpose Gantry Cranes
• ISO 4301 — Cranes: Classification (Duty Class A5–A7)
• AWS D1.1 / ISO 3834 — Structural Welding Qualification
• EN 13001 — Crane Safety — General Design Principles
• Load test certificate and factory acceptance report included with every unit

Why Choose Dafang for Your Semi Gantry Crane?

Henan Dafang Crane has manufactured overhead and gantry cranes for 19 years, supplying mobile gantry and bridge crane systems to clients in more than 30 countries across steel, automotive, logistics, and infrastructure sectors.

• Full in-house capability — structural fabrication, electrical assembly, and load testing all at one Henan production facility; no subcontracting of critical components.
• Custom engineering on every order — span, hook height, duty class, grab/magnet attachments, and explosion-proof specification all configurable without minimum order constraints.
• CE and ISO documentation included — the full compliance package ships with every crane; no additional certification fees for EU and most export markets.
• 19 years of BMG-specific production experience — field-proven joint designs, rail alignment systems, and end-carriage configurations reduce on-site commissioning time.

For technical enquiries, crane load capacity calculations, or a customized configuration proposal, please contact the Dafang engineering team directly.

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FAQ-5 Common Queations

What is the difference between a semi gantry crane and a full gantry crane?

A full gantry crane has ground-level legs on both sides and needs no building structure. A semi gantry crane uses the existing building on one side, cutting civil foundation costs while delivering the same rated capacity and span range.

Which work duty class should for a steel fabrication workshop?

A6 suits most steel fabrication lines with two-shift operation. However, if the crane runs continuously on a three-shift cycle with maximum loads, specify A7. Dafang provides a duty class calculation worksheet on request.

Can the BMG crane operate outdoors or in a semi-open yard?

Yes. With IP54 electrical enclosures, hot-dip galvanised or epoxy-coated structural members, and weatherproof motor housings, the BMG crane is ready for semi-open and fully outdoor duty. Wind load calculations are available for exposed sites.

What certification documentation is provided?

Each crane ships with CE Declaration of Conformity, ISO 9001 quality certificate, full load test report, weld inspection records, electrical schematic, operation and maintenance manual, and spare parts list — the standard documentation package required by most procurement and HSE departments.

How long does delivery take after order confirmation?

Standard production lead time is 30–45 days after drawing approval(6–20 m span, A5/A6 duty, pendant or remote control). Non-standard configurations (non-standard spans, A7 duty, or explosion-proof specification, or outdoor duty with wind load certification) may require 50–60 days. Site installation support is available.

Is the span or hook height adjustable after installation?

Both span and hook height are fixed at manufacture. Therefore, Dafang engineers review building geometry, process flow, and future capacity needs with the buyer during the quotation stage to confirm dimensions before fabrication begins.

About Dafang Crane

Henan Dafang Crane has designed and manufactured overhead and gantry cranes from its integrated Henan production base since 2006. The company supplies BMG semi gantry cranes, double girder overhead cranes, gantry cranes, electric hoists, and crane components to clients in more than 30 countries. Contact the Dafang engineering team for span calculations, duty class review, or a customised configuration proposal.