How Does Road Gantry Work?

Structure on which road signs are mounted For other uses, see Gantry (disambiguation).

A gantry (also known as a sign holder, road sign holder, sign structure or road sign structure) is a traffic sign assembly in which signs are mounted or railway signals are supported on an overhead support. They also often contain the apparatus for traffic monitoring systems and cameras, or open road tolling systems.

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Gantries are usually built on high-traffic roads or routes with several lanes, where signs posted on the side of the highway would be hard for drivers to see. Gantries may be cantilevered or one-sided on the left, right and center (sometimes referred to as a half-gantry or butterfly gantry), or they may be bridges with poles on each side. Similar gantries are used in railway signalling or to suspend overhead lines on multi-track lines.

Gantries are commonly used on urban highways in Canada to support overhead signs, with half-gantries used to place signs near exits where space does not permit having signs to the right side of the roadway. Gantries may also be used to hold cameras for toll road entrances/exits and to hold electronic information signs.

Across Canada, highway signage on gantries is generally green, with blue being used for various specific purposes. For example, on Ontario's 400 series highways, blue signs are used to indicate outer collector lanes, while the standard green signs are used for inner express lanes. Blue signs are also used to indicate Express Toll Routes (such as Ontario Highway 407). Overhead blue signs are also used to indicate roads going into airports.

The style of gantry used are mostly truss gantries. Older gantries have truss supports (round or box) and newer ones are now supported by cylindrical legs. In most jurisdictions in Canada, signs that are mounted on overhead gantries are installed perpendicular to the roadway. In Québec, however, signs are angled slightly face-down towards the roadway such that the sign face is directed towards the motorists below. In New Brunswick, the opposite is true: signs are angled slightly face-up to capture and reflect more sunlight towards the roadway.

Hong Kong's highways use a gantry crane type to support signs. The road signs are usually located on top and some have lights to indicate open or closed lanes.

Gantry signs are being installed at various locations around the trunk motorway network as increasing amounts of traffic mean that road signs at the side of the carriageway are frequently obscured by large goods vehicles. They may also consist of variable-message signs, and more recently Active Traffic Management, to close lanes due to accidents and for other reasons. They can also be used to specify temporary speed limits. Gantries in the United Kingdom display exit (junction) numbers, distances to junctions / exits (1 mile, 1/2 mile, 1/4 mile, 1/3 mile, 3/4 mile, 2/3 mile) and destinations reached, and if necessary what lane to use for them.

Gantry signs are used frequently in the U.S., particularly in urban areas where freeways have an exit every mile to fit in with the grid system. These half-gantries usually have the exit number and the road or street that can be reached. Gantries can also span the whole road, such as at major junctions.

• Truss or latticework designs

• Near Houten, Netherlands
• Gantry in the United Kingdom, with access for maintenance
• On the D.815 road in Turkey
• Super-span gantry near Dublin
• Near Malmö, Sweden

• T-shaped, butterfly or pedestal – signs are mounted onto a T-shaped structure

• Pedestal gantry sign in Georgia
• Butterfly gantry near Raubling, Germany
• On the Jakarta Outer Ring Road
• Gantries placed on either side of the carriageway on the A4 autoroute, France

• Tubular pipes – may be round or square in shape

• A tubular piped (monotube) gantry in California
• Cantilevered gantry in Doha, Qatar
• In Dubai
• Rear view of a gantry in Hungary, with access for maintenance
• Near Frankfurt Airport

• Other designs

• Terminal East gantry sign at Denver International Airport with an empty freeway during the pandemic.
• Older UK gantry, with concrete posts, near Ewloe, Wales

On railways, gantries span multiple railway tracks and carry either railway signals, overhead lines or both. A signal gantry is also used where to improve the visibility of multiple signals, for example around a sharp curve.[1]

• A gantry of British semaphore signals seen from the cab of a steam locomotive
• Gantry with old and new suspended equipment at Grivita railway station, Bucharest.
• Signal gantry in Glasgow Central Station
• Overhead line gantry in Denmark
• Railway overhead line electification gantry Church Road Tottenham London England
• Gantry at Gare Saint-Lazare
• Gantry of Sri Lanka semaphore signals

A gantry is a type of overhead crane designed with freestanding legs. These legs are mounted on wheels and allow the crane to traverse along a track or rail system. This mobility is what sets gantries apart from other cranes. It enables them to operate in various environments, from tight indoor spaces to expansive outdoor settings.

Gantries are adaptable tools and are valuable for indoor sites where the equipment is challenging to navigate around. Their design allows for seamless maneuvering of equipment in complex layouts, making them ideal for lifting and handling art pieces and industrial equipment. In outdoor applications, gantries are used for managing tasks such as unloading cargo from ships. This flexibility makes gantry cranes essential across diverse industries including manufacturing, shipping, construction, and logistics.

At Superior Rigging & Erecting Co., gantries play an integral role in our rigging processes. We specialize in using gantries for tasks that require more precision and careful handling for heavy-duty operations. Our decades of experience in this industry allow us to provide solutions that are effective and tailored to the unique needs of each project. Our use of gantries ensures efficiency and safety, demonstrating our commitment to delivering top-tier service in every endeavor. This blog post will focus on the advantages of using a gantry, its features, stand-out components, and how SRE uses these cranes in action.

Two Types of Gantries

Gantries are important pieces of equipment with various advantages. Their design and functionality offer a blend of strength, versatility, and precision, making them ideal for various applications. There are different types of gantries used in construction projects, each meeting the specific needs of the client. Some of the main types include the portable gantry crane, full gantry crane, bridge crane, and semi-gantry crane.

• Portable Gantry Crane: These cranes, known for their mobility and adaptability, are best suited for light to medium lifting. They are perfect for indoor and outdoor settings where a permanent installation is not needed.
• Semi-Gantry Crane: These gantries combine the design of an overhead bridge crane with a full gantry. These cranes have higher flexibility, with one side supported by an elevated runway and the other side traveling on a ground rail.

SRE’s Gantry Offerings

At Superior Rigging & Erecting Co., gantries are a huge advantage to our rigging operations. These machines allow us to be competitive in the jobs we complete for customers. Many customers have projects requiring heavy lifting in a tight space, and this is where our team comes in. Our expertise in operating the right gantry for each job sets us apart, ensuring efficiency and safety in each project.

Hongrui Manufacturing supply professional and honest service.

Our range of offerings includes:

• Spanco Gantry: These gantries are known for their reliability and versatility, and are typically used for outdoor applications and heavy-lifting projects.
• 1-ton Aluminum Gantry Crane: Aluminum gantries are lightweight and durable tools, offering mobility and ease of use.
• 2-ton and 5-ton Aluminum Gantries: These aluminum gantries are ideal for medium-duty tasks, combining strength with flexibility.
• 3-ton Steel Gantry: These are a sturdy option for more rigorous tasks.
• 2-ton Gantry: This is a versatile gantry that balances capacity and maneuverability for a wide range of applications.
• 400-ton Gantry (with Operator): This is a hydraulic crane that lifts 400 tons of weight. These are used for the most challenging projects and require a skilled professional for operation.

Components and Features of Gantries

As we explore more about gantries, it’s important to understand their components, the building blocks that determine the crane’s functionality, efficiency, and safety. A gantry includes several key components:

• Single and Double Girder: The main difference between girders is the crane’s load capacity and duration of work. Single girders are typically used for light to moderate loads and shorter periods of work, while double girder gantry cranes are best suited for medium to heavy loads and higher levels of work.
• Support Columns: These are the vertical structures that support the girders and the entire crane. They lift and transport heavy loads, providing stability for the crane to operate safely.
• Horizontal Beam: This component, often called the bridge, spans the width of the crane and is the main support for the load.
• Hoist Trolley: The hoist lifts and lowers the load, while the trolley moves the hoist along the horizontal beam. These components work together for precise positioning of the load.
• Wheels: Wheels provide mobility to the crane, allowing it to run across the track or rail system in a straight line.

Safety Features

Safety is the most important factor in the operation of gantries. Modern cranes have several safety features to ensure smooth operations. Overload protection is one feature that prevents the lifting of loads beyond the crane’s capacity. Emergency stop systems are a feature allowing for immediate shutdown in hazardous situations. Anti-collision devices help prevent accidental collisions with other cranes or nearby structures. Lastly, warning alarms alert personnel during crane operations, ensuring everyone is aware of the crane’s movement. At SRE, we make these safety features a top priority in all our operations, ensuring a secure environment for our team and clients.

Materials Used in Construction

The construction materials used with a gantry influence its performance and suitability for different environments. Two common materials used are stainless steel and aluminum. Stainless steel is known for its strength and corrosion resistance. This material is often used in heavy-duty construction projects, especially those operating in harsh conditions. On the other hand, aluminum is ideal for lighter gantries. Aluminum offers portability and flexibility, making it the best choice for indoor and outdoor tasks. With an understanding of the gantry structure and features, one appreciates its capabilities. SRE ensures that every aspect of a gantry’s operation aligns with the highest standards of efficiency and safety.

How Gantry Cranes Work – From Load to Lift

Gantries are more than just towering structures in industrial environments; they are dynamic machines that transform the concept of lifting and moving heavy loads.

The operation of an adjustable gantry crane begins with the accurate positioning of the crane over the load. This process is crucial because it determines the efficiency and safety of the lift. Once the crane is in position, the hoist lowers and hooks to the load with secure rigging. The load’s weight, height, and dimensions are important factors at this stage. They ensure the crane operates smoothly and the load is balanced correctly.

The crane operator then uses a hook device to lift and balance the load. The trolley maneuvers it along the horizontal beam, transporting it to its destination. This movement requires an understanding of the crane’s mechanics and an awareness of the surrounding environment, ensuring a clear path to avoid any obstacles.

The Crane Operator’s Role and Safety Precautions

Crane operators are responsible for controlling the crane and ensuring the safety of the load, the crane, and the workers. This responsibility requires adhering to all safety precautions, such as verifying the load capacity, ensuring correct rigging practices, and communicating with ground personnel. Additional pieces of equipment are used to support the operator’s efforts. These include emergency stop systems and warning alarms, ensuring the smooth operation of the crane.

Gantries in Action

In the construction industry, gantries are solutions that bring efficiency and safety to complex tasks. When considering a gantry crane for your next project, it’s essential to consider various factors to ensure the crane fits into your specific needs.

Understanding the work area is crucial. The size, shape, and conditions of the space where the gantry operates determine the type of crane suitable for the task. Whether it’s a tight indoor space or an open outdoor area, it’s essential to select a crane with the right dimensions and mobility. Another important factor is the adjustable height of the crane. Different projects require different lifting heights and load sizes. From small loads to large, heavy materials, the crane must be capable of lifting the item safely and effectively.

Superior Rigging and Erecting Co.’s Reliable Services

At SRE, we demonstrate our expertise through various projects across the Southeast. One notable example of our gantries is with Aspen Aerogels. We transported nine air handling units, each weighing 12,000 lbs, into a facility with restricted access. We faced several challenges with handling this project, but it demonstrated our ability to adapt to challenging constraints. We utilized our gantry system to successfully deliver on this complex rigging project.

We understand the importance of choosing and operating the right gantry for your project, which is why our team is here to assist you in selecting the right equipment for your needs. It’s important to note that we don’t offer bare rentals. Our gantries include experienced operators, ensuring each task is completed with the utmost safety and expertise. This approach not only guarantees the efficient completion of your project but also ensures adherence to quality and safety standards. If you’re searching for a premium gantry service provider, contact SRE today to learn more!

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For more information, please visit Road Gantry.