How Does a Strand Jack Work? - Bemco Jacking Systems Pvt. Ltd.

In the world of heavy lifting and precision-controlled movement, few technologies have revolutionized construction and engineering projects as much as the strand jack system. Whether you’re erecting a high-rise, moving a bridge section, or lifting an offshore oil platform component, strand jack work is the hidden powerhouse behind many of the world’s most complex lifting operations.

At Bemco Jacks, we specialize in advanced hydraulic lifting equipment, and our strand jack systems are engineered for precision, reliability, and safety—ensuring mission-critical tasks are completed with confidence.

So, how does a strand jack work exactly? In this guide, we’ll break down the mechanics, key components, real-world applications, and why this system is one of the most efficient tools for synchronized heavy lifting today.

What Are Strand Jacks?

A strand jack system is a type of hydraulic jack designed for lifting or pulling loads vertically, like the vertical strand jack by Bemco Jacks or horizontally using high-tensile steel cables known as “strands.” Unlike traditional jacks that rely on direct mechanical contact with the object, strand jacks work by gripping and moving the strand cables in a step-by-step, inchworm-like motion. This allows them to move extremely heavy loads with precision and control.

Originally developed in the 1970s for use in bridge construction and offshore platform installations, strand jack work has evolved significantly. Today, it plays a critical role in modular construction, plant relocation, shipbuilding, and megastructure assembly projects around the globe.

Key Components of a Strand Jack System

To understand how a strand jack works, you need to know its core components. Each part plays a crucial role in the lifting process:

1. Strand Cables

These are high-strength steel cables made of multiple wires wound together. Depending on the load, a single strand jack system may use multiple strands in parallel.

2. Hydraulic Jack (Cylinder Unit)

This is the core of the system. The hydraulic cylinder generates the lifting force. When pressurized, it pulls or pushes the strand cables in controlled steps.

3. Gripping Anchors (Wedge Mechanisms)

These are devices that “bite” into the strand to hold it in place. Each cylinder has two anchors:

One stationary (bottom anchor)
One movable with the hydraulic ram (top anchor)

The anchors grip the cable with steel wedges that engage during motion and disengage during return.

4. Control System

Advanced systems include programmable logic controllers (PLCs) or computer interfaces to allow synchronized movement of multiple jacks. This is vital in heavy lifting operations where multiple strand jack systems work together.

5. Hydraulic Power Pack (HPP)

This provides pressurized oil to the jack system. It controls flow, pressure, and sequencing of the lifting operation.

6. Support Structure or Frame

The jack is often housed in a steel frame or mounted onto a lifting gantry, depending on the application.

The Working Principle: How a Strand Jack Works

Think of a strand jack like a mechanical inchworm. It moves up a strand one grip at a time, ensuring smooth, controlled motion—even when lifting hundreds of tons.

Here’s a step-by-step look at how strand jack work:

Step 1: Initial Gripping

The bottom anchor grips the strand and holds it in place.
The top anchor is open at this stage.

Step 2: Hydraulic Extension

The hydraulic cylinder pushes the top anchor upward (or pulls downward in tensioning scenarios).
Since the bottom anchor is holding the strand, the jack moves up along the strand.

Step 3: Grip Transfer

Once extended, the top anchor closes to grip the strand.
The bottom anchor opens to release its hold.

Step 4: Retraction

The hydraulic cylinder retracts, pulling the strand through the open bottom anchor.
The load moves upward with this motion.

Step 5: Cycle Repeats

This up-and-down sequence of gripping and releasing repeats, gradually moving the load in small, precise steps.

This method allows for exceptional control over the load, which is crucial in sensitive or high-stakes lifting environments. It’s also why strand jack systems are preferred over cranes for certain applications, especially where space or structural constraints exist.

Advantages of a Strand Jack System

The widespread use of strand jack work in global construction and industrial sectors is no coincidence. Its advantages far exceed those of conventional lifting methods, especially when it comes to ultra-heavy, precisely controlled movements.

1. High Load Capacity

One strand jack can lift loads from 10 to 1,000+ tons. By combining jacks in a synchronized setup, entire bridge spans, modules, or offshore rigs can be lifted safely.

2. Compact Setup

Because it doesn’t require a large crane boom or extended space, strand jack systems are perfect for congested job sites or indoor installations.

3. Precision and Control

Advanced hydraulic controls enable millimeter-level accuracy—critical in nuclear facilities, aerospace assembly lines, and bridge segment placement. Our multi strand jack can also be used for multiple tasks with superior precision.

4. Horizontal & Vertical Operation

Strand jack systems aren’t limited to vertical lifts. They are also used for horizontal pulling in skid-shoe systems or heavy equipment relocation.

5. Safe and Synchronized Lifting

When operated with automated control systems, multiple jacks can lift complex structures evenly without risk of imbalance or overload.

6. Modular and Scalable

Need more power? Add more jacks. The system scales easily, which is great for dynamic lifting scenarios or when dealing with unpredictable weight distribution.

Common Applications Across Industries

From aerospace to oil rigs, strand jack work is a silent workhorse powering some of the world’s biggest builds. Here’s how different industries use it:

1. Construction

In the construction industry, the vertical strand jack by Bemco Jacks is used for lifting and positioning large pre-fabricated concrete segments, bridge spans, steel beams, or elevator cores. Strand jack systems are used in projects where cranes would be impractical or too costly.

2. Oil & Gas

Used for module lifting, deck mating, and jacket launching during offshore platform construction. Often paired with skid systems.

3. Power Plants & Infrastructure

Perfect for reactor vessel installation, turbine alignment, or transformer movement where precision and safety are critical.

4. Shipbuilding & Marine

In the shipbuilding industry, heavy component lifting is required during dry dock operations or transferring propulsion units and engine blocks.

5. Industrial Relocation

Moving entire factories or installing large machines using synchronized strand jack systems on skid tracks.

Advanced Control Systems in a Strand Jack System

In complex lift operations involving multiple jacks, coordination is critical. Manual operation can introduce inconsistencies, especially with loads weighing hundreds of tons. That’s why modern strand jack systems now incorporate intelligent control units to manage synchronization, pressure monitoring, and movement precision.

These automated control units, often managed via a central computer, allow operators to:

Program precise lifting heights and
Monitor individual jack pressures in real-
Set load limits for safety shutoff
Control up to 60+ jacks simultaneously in mega lifts

This high level of automation ensures uniform lifting, even when dealing with irregular or multi-point loads. It’s especially vital in projects where structures are sensitive to tilt or uneven stress distribution—like in the aerospace, nuclear, and shipbuilding industries.

Strand Jack vs. Other Lifting Methods

When planning heavy lifts in infrastructure, energy, or industrial projects, selecting the right lifting system can mean the difference between success and delay. Below is a comparison of strand jack systems with other common lifting methods, showcasing why they’re often the preferred solution for modern, complex lifts.

1. Strand Jacks vs. Hydraulic Gantries

Hydraulic gantries are often used in confined spaces, but they require heavy ground preparation and can be sensitive to uneven surfaces.

Precision: Strand jacks offer better synchronization across multiple points.
Mobility: Strand jack systems can be mounted on temporary structures, rooftops, or platforms with minimal space.
Control: With advanced software, strand jacks provide real-time load feedback, unlike manual gantry adjustments.

Winner: Strand jacks for jobs needing superior control and flexibility in tight or elevated locations.

2. Strand Jacks vs. Tower Cranes

Tower cranes are workhorses in vertical construction, but they face limitations with extreme loads or when lifting from below ground level (e.g., shafts, tunnels).

Load Capacity: Strand jacks can easily handle 1,000+ tons. Most tower cranes cannot.
Set-Up Time: Tower cranes need foundation work and a long assembly time. Strand jack systems can be installed faster in modular form.
Environment: Strand jacks are not wind-sensitive like cranes, making them ideal for marine or high-rise work.

Winner: Strand jacks for mega-projects or non-traditional lifting environments.

3. Strand Jacks vs. Crawler Cranes

Crawler cranes are powerful and mobile, but come with logistical challenges.

Space Constraints: Crawler cranes need wide access paths and staging areas. Strand jacks have a compact footprint.
Terrain Requirements: Cranes require ground stability. Strand jacks can be deployed on customized support structures, even on unstable surfaces.
Transport & Setup: Crawler cranes are costly to transport and assemble, especially across rough terrain.

Winner: Strand jacks for remote, elevated, or space-restricted environments.

Why Choose Bemco Jacks?

When precision, power, and performance matter, Bemco Jacks is the name engineers, contractors, and heavy-lift specialists trust worldwide. With multiple decades of expertise in hydraulic systems and lifting technologies, Bemco Jacks has set the benchmark for reliability and innovation — especially in the design and deployment of strand jack systems.

1. Proven Legacy in High-Stakes Lifting

Bemco Jacks isn’t just a supplier, it’s a problem-solver. From oil rigs and bridges to power plants and high-rise construction, Bemco Jacks’s systems have been integral to some of the most demanding lifts across industries. Our products are designed, manufactured, and tested in-house to ensure optimal safety and performance under the toughest conditions.

If you’re looking to understand how a strand jack works, you won’t just find the equipment here, you’ll find decades of insight that translates into real-world success.

2. Engineered for Precision and Control

At the heart of our offering is our cutting-edge strand jack system, engineered for synchronized multi-point lifting and millimeter-level precision. Each jack is built using high-grade materials, equipped with intelligent hydraulic control units, and tested for fail-safe operation. Whether it’s vertical lifting, heavy sliding, or incremental launching, Bemco Jacks’ systems are designed to adapt.

3. End-to-End Support and Training

Choosing Bemco Jacks means more than acquiring top-tier equipment — it means gaining a long-term partner. We offer:

Supervision and commissioning
Operator training and technical support
Maintenance services and spare part availability
Remote diagnostics and troubleshooting for modern systems

Our commitment to safety, uptime, and knowledge-sharing ensures your team is always prepared and your project stays on track.

Conclusion

The evolution of strand jack work has transformed the way industries handle ultra-heavy and high-risk lifts. From lifting massive bridge segments to aligning nuclear reactor cores, strand jack systems offer unmatched control, scalability, and safety.

In 2025 and beyond, as infrastructure projects grow in complexity and sustainability becomes a key concern, the demand for intelligent, space-efficient lifting solutions is only set to rise. That’s where Bemco Jacks steps in.

As one of India’s leading manufacturers of hydraulic jacks and lifting systems, Bemco Jacks offers industry-grade strand jack systems built to perform under pressure—literally. Our systems are designed with modularity, reliability, and operator safety in mind, making them ideal for construction, oil & gas, railways, shipping, and more.

Whether you’re involved in a modular high-rise, an offshore platform, or a railway bridge upgrade, knowing how a strand jack works—and having the right equipment partner—can make or break your project’s success. Contact us today to equip yourself with the best jacks on the market.

So the next time you’re looking at an architectural marvel or industrial megastructure, remember: there’s a good chance a strand jack system was behind the lift.

FAQs

1. How safe are strand jack systems?

Extremely safe when operated by trained professionals using certified equipment. Modern systems include fail-safe hydraulic controls and real-time monitoring to prevent imbalance or overload.

2. Can strand jacks be used for horizontal movement?

Yes. While commonly used for vertical lifting, strand jack are also used in horizontal pulling or skidding systems to move large equipment, especially in industrial relocations.

3. What kind of maintenance is required?

Routine hydraulic system checks, strand inspection, wedge replacement, and software diagnostics are essential. High-quality systems like those from Bemco Jacks are built for longevity with minimal wear and tear.

4. Are strand jacks better than cranes?

Not necessarily better, but different. Cranes are ideal for dynamic, overhead movement. Strand jack work excels when you need synchronized, slow, heavy, and extremely precise motion, especially in confined or indoor spaces.

5. Where can I buy or rent a strand jack system in India?

Bemco Jacks is a leading manufacturer and supplier of high-quality strand jack systems tailored for multiple industries, including construction, shipping, railways, and oil & gas.