Crane Systems: Single-Girder, Double-Girder and Gantry

Types of Crane Systems Available for Design & Fabrication

The selection of the appropriate crane system depends on load capacity, building span, available headroom, operating requirements, frequency of use, and the condition of the existing supporting structure.

Single-Girder Overhead Crane

A single-girder overhead crane uses one main bridge girder to support the hoisting system and is widely used in industrial halls, workshops, warehouses, and production lines.

Where load capacity, span, and operating conditions permit, a single-girder configuration can reduce structural weight and simplify fabrication and installation.

Typical applications of single-girder overhead cranes include:

• Industrial workshops

• Production halls

• Industrial warehouses

• Assembly lines

• Maintenance facilities

• Light- and medium-duty manufacturing plants

The section type and specifications of the main bridge girder are determined for each project based on structural calculations and actual operating conditions.

Double-Girder Overhead Crane

A double-girder overhead crane uses two parallel main girders to form the crane bridge.

This configuration is typically considered where higher load capacity, longer spans, heavier-duty service, or specific lifting-height requirements apply.

Double-girder overhead cranes are widely used in heavy industrial environments where equipment and heavy components must be handled frequently or continuously.

Typical applications include:

• Steel plants

• Machinery manufacturing facilities

• Cement plants

• Mining operations

• Oil and petrochemical facilities

• Heavy equipment production halls

• Structural steel fabrication workshops

• Heavy industrial production lines

The main girders, connections, and structural components of a double-girder crane are engineered according to the required capacity, span, and operating conditions of the project.

Gantry Crane

A gantry crane is suitable for applications where the building structure or overhead crane runway cannot be used, or where load handling is required in outdoor areas.

In this system, the crane bridge is supported by structural legs and travels along a defined runway.

Gantry cranes can be designed for applications such as:

• Factory yards

• Outdoor storage areas

• Heavy component production facilities

• Steel industry applications

• Equipment fabrication workshops

• Loading areas

• Outdoor assembly lines

• Handling of structural steel and industrial components

The overall dimensions, leg height, span, and load capacity of the gantry crane are engineered to suit the specific project conditions.

Engineering Design of Crane Systems

One of the most important stages in crane bridge design and fabrication is collecting accurate project information before structural calculations begin.

The following parameters should be evaluated during the design process:

Crane Load Capacity

Load capacity is one of the primary design parameters and directly affects bridge girder dimensions, structural weight, connections, and associated components.

Crane Span

The distance between the crane runways defines the bridge span. Longer spans generally require more detailed evaluation of girder strength, deflection, and overall structural stability.

Lifting Height

The required lifting height must be coordinated with the available building headroom, crane bridge elevation, and hoisting equipment.

Duty Class & Operating Conditions

A crane used occasionally in a workshop has different design requirements from a crane operating continuously on an industrial production line.

Existing Building & Structural Conditions

For projects within existing buildings, columns, crane runway girders, travel paths, roof clearance, and installation constraints must be evaluated before crane bridge design begins.

Travel Speed & Movement

Bridge travel, cross travel, and load-handling requirements can influence the technical specifications and overall design of the crane system.

Crane Systems: Fabrication and Installation at ASAECO

The delivery of an industrial crane bridge involves several engineering, fabrication, inspection, and installation stages.

1. Project Information Review

The required crane capacity, span, lifting height, installation location, operating requirements, and building conditions are reviewed at the initial stage.

2. Engineering & Structural Calculations

Once the initial project parameters are defined, the crane bridge structure and associated components are engineered according to actual project conditions.

3. Preparation of Fabrication Drawings

Fabrication and shop drawings are prepared, including details of the main girders, plates, stiffeners, diaphragms, and structural connections.

4. Factory Fabrication

Steel plates and components are prepared according to approved fabrication drawings, followed by cutting, fit-up, assembly, and welding.

5. Dimensional Inspection & Quality Control

Component dimensions, alignment, connections, and fabrication quality are inspected before delivery to the project site.

6. Surface Preparation & Coating

Surface preparation and the specified protective coating system are applied according to the environmental and project requirements.

7. Delivery to Site

After fabrication is completed, components are identified, marked, and transported to the project site for installation.

8. Installation & Final Alignment

The crane bridge is installed on site, followed by final checks of alignment, travel path, and coordination with the crane runway girders and rail system.