The slipform construction method has undoubtedly become one of the most popular and commonly used construction techniques. Simply put, slipforming is a method in which concrete is poured into a formwork that is in a state of continuous motion. In nature and application, slipform can be considered similar to climbing form or jump form. What distinguishes the techniques is mainly how the formwork is moved. In climbing / jump form the formwork is regularly dismantled and re-assembled at the next casting position. In slipforming, on the other hand, the formwork is already moving while casting takes place.
Why use slipform?
Slipform is undoubtedly the fastest and most economical construction method available for high-rise concrete structures. The technique offers a construction rate of 4m-8m per 24h (about 5-7 times faster compared with conventional methods).
Slipform is also a very safe construction method since there is no need for continuous dismantling and re-assembly of formwork by crane during the construction phase– the complete set-up is assembled only once at ground level before “take-off”. During an entire construction project, this also saves a lot of time.
Benefits of slipforming
The main reason why the slipform technique has become commonplace in construction projects worldwide, is because of its numerous advantages. As mentioned, the construction speed with slipform is many times faster than other methods. Slipforming is also known for its high rate of output. However, the process requires careful planning and execution because there is little scope for change once the continuous concreting commences.
How does slipform construction work?
Ever since the first Hydraulically Controlled Slipform method was invented by Bygging-Uddemann in 1943 it has been based on the same basic principles; Hydraulic jacks – continuously lifting a complete formwork with work decks, 25-30mm at the time, 24 hours a day – climbing on embedded steel rods inside the curing concrete. As the concrete gradually cures, the slipform creates a seamless concrete structure in one pour from the bottom to the top.
With the experience from developing numerous of slipform solutions for a variety of concrete structures (silos, chimneys and other high rise towers) Bygging-Uddemann can even present tailor-made slipform set-ups solely for the construction of, for example, conical wind power towers as an answer to the demand for a fast, safe and economical solution for the growing wind power industry.
Our reputation is built on slipforming and we’re specialists in all types of traditional slipforming, gantry slipforming and conical slipforming. Contact us for slipform construction.
You can read more about the different slipforming types below.
The slipform technique is based on hydraulic slipform jacks. The slipform jack is continuously lifting a complete formwork with work decks and workers, 25-30mm at the time, 24 hours a day – climbing on embedded steel tubes inside the curing concrete. As the concrete gradually cures, the slipform creates a seamless concrete structure in one pour from the bottom to the top.
The slipform technique offers a construction rate of 4m-8m per 24h. It’s undoubtedly the fastest and most economical construction method available for high-rise concrete structures – about 5-7 times faster compared with conventional methods.
It depends on several factors. Where the project is located, how complex it is and if we need to manufacture new parts, or if they are already in stock. As a rough approximation, assume 5 to 10 weeks for the design and preparation of slipform equipment from our workshop. Shipping within Sweden is estimated at one week, to Europe 2-3 weeks, to the USA and the Middle East 5 weeks, and to Africa and East Asia takes about 7 weeks. The supplier normally commits to a delivery schedule for its commitment.
We usually deliver our equipment in standard containers (20ft or 40ft). When equipment is to be sent between different parts of the world, it is done by boat. Transport from port to location and back to port is normally handled by the customer. Delivery terms can be made by agreement between the parties.
It depends a lot on the size and complexity of the project – from a few days to several weeks. The customer can undertake to assemble the equipment, or if it is agreed, it is done under the guidance of our supervisors.
The slipform process is not disturbed by rain. Excess water is not actively mixed into the concrete. In wet climates and particularly exposed areas, the slipform rig can be covered by a lightweight roof construction supported by the slipform yoke.
Inspection and maintenance during slipforming takes place regularly. Cleaning of formpanels, checking the function of pumps, hoses and jacks. This is done by our supervisors if we have one on site.
In addition to this, the slipform result also needs to be checked. This is usually done using a laser measuring equipment. Please note that control and measurement of the slipform results is always the customer’s responsibility. The construction process can be facilitated by giving the slipform operator access to the measurement results. Then easy adjustments can be made to optimize the result.
Depending on the size of the project, the dismantling takes from a few days to a few weeks. You can calculate that a disassembly takes about half as long as the first assembly. We will provide guidance on how to proceed and if we have a supervisor on site, he or she, will lead the work.
This depends a lot on the size of the project. Each project requires at least one main supervisor and enough concrete workers, carpenters, and welders to keep up with production (so that the sliding speed will remain constant). We usually send an expert to supervise the assembly and the slipform process, while the main contractor delivers the work staff.