Slipform Construction Along with the Segment Erector is Indicating a New Direction in Modern Infrastructure Development
The construction industry has changed dramatically over the past few decades due to the advancements in technology and equipment available to accomplish the work. The introduction of these new technologies and the introduction of new forms of construction have dramatically increased the efficiency, safety, and overall quality of all structures built within this industry. The combination of slipform construction with the segment erector has revolutionized the way in which large-scale infrastructure projects are built (e.g., bridges, roads, sky rails, silos, chimneys, and tall buildings). These two technologies are allowing for more precise, less-time consuming, and more economical ways to construct these types of structures.
This article will cover basic principles of slipform construction, the function and use of segment erectors, and how these technologies influence modern infrastructure development projects.
What Is the Definition of Slipform Construction?
The definition of slipform construction is to perform the repetitive task of casting concrete continuously. In other words, it is the use of a certain method of moving the form upwards (or horizontally) at a pre-determined rate of speed during the casting of or curing of the concrete; therefore continuous and uninterrupted progress is being made. Traditional formwork systems require significant time to assemble and disassemble each form before commencing the next casting operation; where as the slipform construction process eliminates this interruption thus resulting in a considerable amount of time saved on project timelines.
Slipform construction methods are predominantly used for structures that will be constructed with a uniform cross-section, i.e.:
High-rise building cores
Bridge Piers and Pylons
Cooling Towers
Silos and Storage Tanks
Chimneys and Towers
Therefore, the formwork is mechanically “slipped” up by means of hydraulic jacking systems so that the structure is continuously lifted up without any connection joints.
Advantages of Slipform Construction
The benefits of slipform construction are numerous and ideal for large-scale repetitive buildings:
1. Speed of Construction
By pouring a continuous strip of concrete, slipform construction allows for no delays in construction due to waiting for materials to arrive before starting again, which helps speed up the overall process compared to traditional methods.
2. Increased Strength of Completed Structures
With no cold joints created from multiple pours, finished structures are much stronger and durable than if constructed using traditional methods.
3. Cost-Effective Construction Method
While the setup costs for slipform construction may be higher, the lower number of labour hours and reduced time to complete the project will result in overall reduced project costs.
4. Consistency of Quality
All slipform structures can expect a consistent quality of finish and dimensional accuracy due to controlled pouring and curing processes throughout each pour in the finished structure.
5. Reduced Dependence on Crane Use
Most slipform systems are self-climbing, which means there is significantly less reliance on heavy lifting equipment.
The Use of Slipform Construction in Infrastructure Projects
Slipform construction has become an alternative to conventional construction methods for infrastructure projects that require vertical or linear continuity. In bridge construction for example, slipform is regularly used for the construction of medium to tall piers and pylons. Industrial projects — such as silos and chimneys — also utilize slipform technology for joint-free, seamless, and structurally strong systems.
Combined with precast construction techniques, slipform systems are a critical component of modern day bridge and metro construction projects (especially when a segment erector is being used).
The purpose of a segment erector is to assist with assembling and erecting precast concrete segments. Precast concrete segments are produced off-site in a controlled factory environment and delivered to a construction site for assembly. For example, a segment erector is necessary for constructing metro rail viaducts, flyover and elevated highways, long span bridges, and many types of urban infrastructure projects.
A segment erector provides high precision when positioning heavy precast concrete segments; it is also designed to provide both safety and efficiency during the construction process.
Segment erectors can either operate from above (with an overhead launching gantry) or below (via an underslung system). They will lift, align, and install precast segments into their designated position according to drawings. Once the precast segments have been aligned and placed, they are temporarily held in place until being posttensioned or permanently fixed upon completion of the installation. A modern segment erector will typically have:
- very sophisticated hydraulic systems
- precise controls for aligning the precast segments
- safety devices to lock the precast segments into place
- a very large capacity for supporting heavy precast concrete segments.
Therefore, segment erectors are the most critical piece of equipment for projects where millimeter accuracy is required for the placement of pre-cast concrete segments.
Advantages of Implementing a Segment Erector
1. Improved Safety at Construction Sites
By reducing manual handling and working at height, segment erectors increase the level of safety
2. Increased Construction Efficiency and Speed
They are able to build segments quickly which is important for projects that are time sensitive in nature within the urban environment.
3. Precise Construction
The segments are accurately placed in position to help ensure structural integrity and reduce re-work.
4. Minimal Disruption to Traffic Flow
Erection can often occur above existing roadways or rail lines, so erection of the segments will have minimal impact on the surrounding congested urban environment.
Slipform Construction and Segment Erector are Complementary Construction Methods
While slipform construction and segment erector systems are used for different purposes, they are frequently used to work together to form larger infrastructure projects.
Slipform construction typically is used to create cast-in-situ continuous vertical or linear structures such as piers or cores.
Segment erectors are typically used for precast segmental construction, which is particularly well suited for the construction of superstructures such as bridge decks or metro viaducts.
In an instance where there is a metro line or bridge project, slipform construction may be used to create piers and pylons, and a segment erector will be used to place the precast deck segments. This hybrid construction process allows for maximum speed, quality, and cost-effectiveness.
Sustainable construction methods align with modern construction techniques including slipform and segment erectors. Slipform construction creates minimal waste through improved concrete usage while precast segmental construction mitigates pollution and noise through minimized jobsite activity.
Pre-manufactured segments provide improved quality control, lower carbon footprint and material efficiency (compared to conventional methods) which supports sustainable building and infrastructure criteria.
Future Perspective
As the demand for fast-growing urban infrastructure along with smarter cities and larger transport networks increases, the use of slipform and segment erectors will continue to increase to meet the challenge. In addition, technology advances in automation, digital monitoring, and AI-assisted control will enhance the safety, performance, and accuracy of these methods.
Construction firms and developers that utilise these technologies will benefit from a competitive advantage by completing projects more quickly, safer and at a higher level of quality.
Final Thoughts
The Segment Erector and slipform construction methods are two of the key backbones of the current state of infrastructure development. While slipform construction allows for the creation of uninterrupted, continuous concrete structures when combined with segment erector technology, it allows for the highly productive installation of precast concrete segments. The two construction techniques together provide a compelling combination capable of meeting the challenges of today’s increasingly complex, large-scale construction projects.
As demand for infrastructure continues to grow, these advanced construction methods will be instrumental in providing the framework for efficient, durable and sustainable built environments.