How Are Tower Cranes Erected

How Are Tower Cranes Erected

Meta Description: Learn the step-by-step process of erecting tower cranes, from planning and site preparation to assembling components and adding sections on construction sites

Tower cranes are vital to many construction projects involving tall buildings and structures. While these cranes are common on construction sites, erecting them is pretty complex.

This article provides a detailed overview of the step-by-step process for tower crane erection. From planning and site preparation to assembling components and adding sections, we will explain each phase of erecting tower cranes.

Key Takeaways

• Tower crane erection is a complex process involving careful planning, assembly of components, and incremental height increases.
• A sturdy foundation and initial mast sections are critical to support the entire crane structure safely.
• The climbing frame and hydraulic jacks enable precise guidance of additional mast sections into place to extend the crane’s reach as needed.
• Components like the counterweights, slewing unit, and lifting assembly must be correctly installed to lift and maneuver loads safely during construction.
• Following each step in sequence while enforcing safety protocols is important for efficient and risk-free erection, climbing, and eventual dismantling of tower cranes on busy construction sites.

Understanding Tower Cranes Erection

Tower cranes are vital in many construction projects involving tall structures like buildings and bridges. Their primary function is to lift and lower materials and equipment during construction.

Tower cranes consist of a vertical mast or tower with lifting components attached. The mast supports the counterweight and jib, allowing the crane to lift heavy loads.

Planning for Tower Crane Erection

Proper planning is essential for safely and efficiently erecting tower cranes. Several factors must be considered during the planning stage, such as the intended construction project, load requirements, site conditions, and local regulations. A detailed plan ensures all necessary approvals and preparations are in place before assembly begins.

Site Preparation

One of the first steps in planning is evaluating the construction site to ensure it can adequately support a tower crane. The ground must be leveled, compacted, and stabilized if required. Perimeter protection like barricades and warning signs are also installed at this stage.

Concrete foundations are then poured with steel reinforcements to provide a sturdy base for the crane mast. Complex calculations determine the appropriate foundation design based on load and soil conditions.

Foundation Requirements

The concrete foundation is one of the most critical components in tower crane erection. It must support the immense weight of the fully assembled crane and any loads it lifts.

Based on soil conditions and estimated weights, complex calculations determine the foundation’s appropriate thickness, depth, and reinforcement. Proper drainage is also considered to prevent water accumulation that could weaken the foundation over time.

Permitting Process

Before the erection process begins, necessary permits and approvals must be obtained. This involves submitting structural plans and calculations to local authorities for review. Permits are required to assemble cranes according to building codes and safety standards.

The permitting process may require modifications to plans based on authority feedback. Only after all permits and sign-offs are received from relevant bodies can erect tower cranes formally commence.

Initial Assembly

After completing all planning and permitting, the next step is assembling the initial components of the tower crane on site. This stage lays the foundation for the whole erection process.

• Setting Up The Base and First Mast Section: Using mobile cranes, the first section of the mast is lifted and bolted onto the prepared concrete foundation. This forms the base for the entire crane structure. Anchor bolts securely fasten the mast section to transfer its immense weight loads to the foundation. Additional sections are stacked and bolted to assemble other components to achieve the desired initial height.
• Installing The Slewing Unit: At the top of the assembled mast, workers attach the slewing unit. This heavy-duty turntable allows the upper crane structure to rotate 360 degrees. It is the base for the lifting components and the operator’s cab. The slewing unit is precisely positioned and bolted into place to support the counterweights and jib.
• Attaching The Lifting Components: With the slewing unit installed, workers then lift and connect the counter jib and working jib. Steel tie rods securely join the opposing jibs. The cathead is assembled above to transfer load between the jibs and mast. This completes the initial lifting assembly, which will be used to raise additional mast sections.

Reaching Initial Height

Once the base components are assembled, the next step is raising the tower to its initial operating height. This allows it to function while additional sections are added later.

• Adding Mast Sections With Mobile Cranes: Mobile cranes lift subsequent mast sections into place. Workers carefully guide each section into position before securing it with bolts. This process is repeated until reaching the desired initial height for the crane.
• Securing Sections With Bolts: Every mast section added is firmly bolted to the one below it using heavy-duty fasteners. This bolted connection ensures each section can withstand tremendous lifting loads without movement. Precise alignment is critical, so weight is evenly distributed throughout the tower structure.

Enabling Height Increases

While initial height is achieved using mobile cranes, climbing raises the crane even higher for taller construction projects.

• Assembling The Climbing Frame: Workers first construct the climbing frame – a lattice structure that will climb the mast. It is temporarily fastened around the lower mast section.
• Lifting and Securing The Climbing Frame: A hydraulic jack lifts the entire climbing frame and attached mast sections. It is secured at the new height before the process repeats to add further sections. This continues until reaching the crane’s maximum operational height.

Continued Climbing

The climbing process enters the next phase of incrementally increasing the tower crane’s elevation at the job site.

• Inserting New Mast Sections: A new mast section is lifted with the climbing frame in position. It must be precisely guided to engage the climbing frame smoothly.
• Repeating The Climbing Cycle: Once secured, the hydraulic jack resumes lifting the assembly higher before locking it off. This cycle of lifting, inserting, and securing sections is repeated until the crane reaches its necessary height for the construction project.