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Box‑Girder‑Top Lattice‑Leg Gantry Crane
Box‑girder‑top lattice‑leg gantry crane (also named upper‑box lower‑truss hybrid gantry crane) is special hybrid‑structure rail‑mounted gantry crane. It combines closed box‑type main girder on top and open lattice‑truss support legs below.
Yangyumech hybrid gantry crane covers capacity from 5‑50 ton, span 7.5‑32 m. It integrates high torsional rigidity of box‑girder and excellent wind‑resistance & light‑weight merit of lattice truss legs. Reduce foundation bearing pressure, perfectly adapted for open‑air windy outdoor stockyards, steel‑material yards and precast‑component sites.
Description
Typical Application & Site Pre‑Conditions
Box‑girder‑top lattice‑leg hybrid gantry crane is widely used for open‑air windy‑condition sites:
‑ Steel‑material storage stockyard, steel‑profile handling
‑ Pre‑cast concrete component production yard
‑ Outdoor heavy‑equipment assembly, machinery storage yard
Important site‑pre‑condition:
1. Requires reinforced concrete rail‑foundation; thanks to lattice‑leg light‑weight feature, foundation bearing requirement can be reduced by 15‑20%.
2. For open‑air deployment, anemometer & wind‑speed interlock protection is mandatory, withstand gust up to Beaufort scale 8‑10.
3. Storm anchoring device must be equipped for long‑term outdoor idle‑state.
Mainly for outdoor rail‑mounted operation; ambient temperature:‑20℃ ~ +40℃.


Core Structural Composition
1. Upper closed box‑type main girder: Q355B high‑strength welded box beam, high torsional stiffness, deflection controlled ≤L/1000. Provide stable running track for trolley hoist, resist heavy‑load torsion and horizontal impact force.
2. Lower lattice‑truss gantry legs: Assembled by angle steel / channel‑steel via welding & bolt connection. Open‑web truss structure, low wind‑resistance coefficient ≤0.5, greatly cut self‑weight and foundation load.
3. Travelling end‑carriage & rail wheel group: Run on ground rail system, transfer crane total load to concrete foundation.
4. Hoist trolley unit: Equipped with wire‑rope hoist for material lifting task.
5. Electrical control system: Support basic contactor control or full VFD variable‑frequency upgrade.
Custom Purchasing Process
1. Submit inquiry: Provide rated lifting capacity, span, lifting height, cantilever over‑hang length, working‑duty(A3‑A6), outdoor site wind‑condition, hoist‑type, control‑mode, special‑environment requirements(coastal anti‑corrosion / explosion‑proof).
2. Custom technical drawing & quotation: Our engineering team delivers tailored layout drawing and formal quotation within 24 working hours.
3. Order confirmation: Confirm technical drawings, specifications, delivery cycle and commercial terms.
4. Production & strict‑quality‑inspection: Raw‑material inspection, welding UT non‑destructive‑test, dynamic‑static‑load factory‑acceptance‑test.
5. Seaworthy export‑packaging & ocean shipment; deliver full‑set export‑oriented certification documents.
6. After‑sales support: Installation‑guidance manual, remote‑technical‑service and long‑term spare‑parts supply.
Features
1. Unique hybrid structural solution: upper closed box‑girder + lower lattice‑truss legs. Combine high torsional stiffness of box‑beam and superior wind‑resistance of lattice‑truss support.
2. Q355B high‑strength steel box‑type main‑girder; torsional stiffness 40% higher than full‑truss main‑beam. Max deflection ≤L/1000 under full rated‑load, guarantee heavy‑load stable hoisting.
3. Lattice‑truss support‑leg adopts angle‑steel / channel‑steel welded triangular structure. Reduce total dead‑weight by 20‑30%, cut foundation bearing‑capacity requirement by 15‑20%, lower civil‑work investment.
4. Low wind‑resistance coefficient ≤0.5 for truss‑leg; can adapt open‑air site under Beaufort scale 8‑10 gust wind condition.
5. Wide parameter coverage: span 7.5‑32 m, lifting‑height 6‑24 m, support A3‑A6 multiple working‑duty grades.
6. Optional bilateral cantilever over‑hang design to enlarge effective material‑handling working zone.
7. Complete outdoor‑oriented safety‑protection suite: anemometer wind‑speed interlock, infrared anti‑collision, storm anchoring device for idle‑state anti‑overturning.
8. Modular component‑design, convenient for on‑site assembly, inspection and spare‑part replacement.
Technical Data
| Capacity | 1t | 2t | 3.5t | 5t | 10t | 16t | 20t |
|---|---|---|---|---|---|---|---|
| Span | 7.5-18m | 8-20m | 10-22m | 12-25m | 14-8m | 16-30m | 18-32m |
| Lifting height | 6-12m | 6-14m | 8-16m | 8-18m | 10-20m | 12-24m | |
| Work Duty | A3-A4 | A4 | A4-A5 | A5 | |||
| Lifting speed | 8/0.8m/min | 6/0.6m/min | 5/0.5m/min | 4/0.4m/min | |||
| Hoist Traveling Speed | 20-30m | 25-35m | |||||
| Crane Traveling Sprrd | 10-30m | 15-35m | 20-40m | 25-45m | 30-50m | ||
| Rail | P22 | P22-P28 | P28-P38 | P38-QU70 | QU70-QU80 | QU80-QU100 | QU100-QU120 |
Purchasing Process




Our Crane Certifications
Our cranes (overhead crane, gantry crane, jib crane and electric hoist) are fully certified to meet international and local manufacturing standards. We hold complete qualification documents to guarantee product safety and reliable quality for global buyers. Below are our key certifications:
- ISO 9001 Quality Management System Certificate
- ISO 45001 Occupational Health & Safety Management Certificate
- Special Equipment Type Test Certificate for Lifting Machinery
- Manufacturing License for Lifting Equipment
- Third‑party Independent Audit Certificates
- Complete Export‑Oriented Qualification Documents
Our Custom Visit
We welcome worldwide customers to visit our manufacturing workshop. You can check crane production processes, raw materials and finished products face‑to‑face with our engineering team.
- Customized Crane Solution Design
- Professional Technical Consultation & Quotation Support
- Production Tracking & Quality Supervision
- Overseas Shipping & Complete Document Service
- After‑sales Technical Support & Guidance


FAQs About Choosing the Right Gantry Crane and Supplier
In order to obtain accurate quotes for custom overhead cranes, providing the following core information will greatly improve efficiency:
1. Key specifications: including rated lifting weight (tons), span (i.e., track spacing, meters), and lifting height (meters), which is the basis of the design.
2. Use environment and working conditions: Explain the conditions of the installation site (such as indoor/outdoor, temperature, humidity) and work level (busy level), which determines the material selection and configuration level of the structure.
3. Specific configuration requirements: clarify the drive mode (such as frequency conversion control), brand preferences for electrical components, safety devices (such as overload limiters, anti-collision systems), and whether special functions such as remote control are required.
4. Installation and service: confirm the on-site power supply conditions (voltage, frequency), installation conditions, and specific expectations for delivery time, installation and commissioning, and after-sales service.
The more detailed the information provided, the more accurate and reliable the solutions and quotations obtained.
1. Span and lifting capacity: this is the foundation.The larger the span and the higher the rated lifting weight, the material and design costs of the main beam and structure will increase significantly, and the higher the price.
2. Working level and frequency of use: The working level (A1-A8) represents the busy level and load status of the crane.Cranes with frequent and heavy-duty use require more durable motors, gearboxes and structural parts, and the cost is naturally higher than that of lightweight and occasionally used equipment.
3. Structure and configuration: The double beam is more complex and stable than the single beam structure, and the price is higher.At the same time, the lifting height, operating speed, motor brand, control system (ordinary vs frequency conversion), and the level of safety devices (such as anti-swing, load monitoring) all directly affect the final quotation.
4. Degree of customization and brand service: completely standard models have lower costs.The customized design based on the workshop environment (such as explosion-proof and high temperature), special processes (such as metallurgical special), brand added value, and after-sales guarantee system will all be reflected in the price.
In simple terms, when buying a bridge crane, it is necessary to consider “how much, how frequently, what environment and what configuration”, which determine its core value and price.
Which crane to choose mainly depends on your specific needs. You can quickly judge from the following four core aspects:
-Single-beam bridge crane: it is suitable for conventional workshops with light and medium loads (usually ≤20 tons), medium span, and low frequency of use. It is the most economical and versatile choice.
-Double-girder bridge crane: used for heavy-duty, long-span, or high-work-level occasions (such as frequent hoisting, metallurgy, heavy-duty assembly). Its stability, durability, and safety are higher, but the cost is also increased accordingly.
-Free vertical crane (cantilever/column type): suitable for fixed working points and working conditions with limited rotation range, such as beside machine tools, maintenance areas, or production line stations, it can efficiently use corner space and be installed flexibly.
-Grab crane: It is specially used for the handling, loading, and unloading of bulk materials (such as grain, coal, sand, and gravel). The only reason to choose it is that you need to deal with such unpackaged loose materials.
In simple terms, you can filter according to this logic:
First, according to the lifting weight and span, choose between a single beam and a double beam.
If the scope of operation is highly concentrated and the space is limited, consider a free vertical.
If the handling object is bulk material, it points directly to the grab type.
Delivery times largely depend on whether the crane is standard or customized. Based on our experience, standard single-girder and double-girder cranes can be produced more quickly, while cranes with special spans, duty ratings, or environmental requirements naturally require additional engineering design time.
For each quotation, we provide an estimated production and delivery schedule based on your configuration and destination. Throughout the manufacturing process, our team maintains communication with the customer to ensure no unexpected issues arise before shipment.
Compared with many suppliers, Yangyumech mainly reflects the two differentiated advantages of high customization flexibility and clear international compliance when providing bridge cranes.
On the one hand, we focus on in-depth customized services. According to your specific needs, we can provide fully customized solutions on core parameters such as rated load capacity, span, and lifting height, and accept personalized requirements. This means that what you get is not a standard product, but exclusive equipment that accurately matches the working conditions of your workshop.
On the other hand, we attach importance to international standards and quality certification. Our products clearly meet the requirements of international certifications such as CE, which ensures that their safety and reliability can meet the mainstream standards of the international market, and provides you with additional quality confidence guarantees. Combined with our direct supply capabilities as a powerful factory, we can achieve better comprehensive value for you while obtaining compliant and customized products.
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