Concrete can be continuously poured thanks to a revolutionary construction method called sliding formwork. With sliding formwork, as opposed to traditional methods, which involve pouring concrete in sections and letting it solidify before continuing, a series of forms move gradually upward as the concrete is poured. This provides strength and efficiency in the construction of tall buildings such as skyscrapers, chimneys, and silos.
This approach has special benefits for projects that call for repetitive and vertical structures. A hydraulic jacking system supports the sliding forms, ensuring their smooth and steady movement. Workers can continuously add concrete, steel reinforcements, and other materials as the forms rise. As a result, there are no joints in the monolithic structure, greatly increasing the construction’s durability.
Sliding formwork has several advantages, one of which is how quickly construction can be finished. Projects can proceed far more quickly than with conventional formwork techniques because there is no need to wait for portions of the concrete to cure before moving forward. This is a financially sensible option for major construction projects since it shortens the construction period and uses less labor and resources.
Sliding formwork is also renowned for its adaptability. It can be applied to many kinds of projects and in various environments. The versatility of sliding formwork makes it a popular option for many engineers and builders, regardless of the project—whether they’re building a high-rise structure or a cylindrical water tower. Better structural integrity and longevity are the results of its capacity to build sturdy, homogeneous structures with fewer joints and seams.
| Topic | Details |
| Definition | Sliding formwork is a method used in construction where the formwork moves upward as concrete is poured, allowing for continuous and efficient construction of vertical structures like towers and silos. |
| Advantages | Sliding formwork enables faster construction, reduces labor costs, and results in smoother surface finishes. It also minimizes joints, improving the structural integrity. |
Scope and design
Sliding formwork is designed with two rows of identical panels that can reach a height of 1.2 meters, supported by wooden beams. The structure can be raised evenly because the panel frame is attached to a metal frame that has jacks installed on it.
For sliding formwork, jacks can be:
- Manual. This is the cheapest option, however, manual jacks require frequent repairs. In addition, they are very inconvenient to use when building with your own hands.
- Hydraulic. Equipment of this type is much more common. Such systems work thanks to connected pumps, which allow the entire group of jacks to function at once.
- Electric. Such models are the most expensive, however, they are considered the most modern, due to their trouble-free operation and low weight. When using a jack, you will not have to put in much effort.
Even though using sliding formwork to help with concreting can save a lot of time during construction, installing a sliding frame is thought to be a fairly specific procedure. A design like this will only make sense if you are building:
- adjacent high-rise buildings;
- a single building, the height of which exceeds 25 m;
- silo;
- chimney;
- cooling tower;
- well.
Such technology is rarely used when building a private residential home by hand because it would be difficult to arrange windows and other openings, communications holes, and many other details. The standard fixed vertical formwork will be a better and easier choice in this situation.
It’s also important to consider the additional drawbacks and benefits of sliding formwork.
Pros and cons of sliding formwork
The following are some benefits of this design:
- high pace of work;
- construction costs are reduced by 15-20%;
- the ability to build complex structures with different geometries.
But these frames have a lot of drawbacks (with regard to private construction):
- it is difficult to install reinforcing frames inside the formwork;
- pouring the floors becomes more labor-intensive;
- since the pouring of the concrete mixture and the lifting of the frame must be carried out continuously, a whole construction team will be required;
- when pouring concrete in winter, additional costs will be required for heating the solution;
- if the technological process for installing the structure is not followed, the efficiency of using sliding formwork is greatly reduced;
- for this type of structure, it is necessary to use concrete of the highest quality and plasticizing additives;
- the formwork must be raised strictly vertically;
- in case of an error, the cost of eliminating defects will be very high.
You can make good use of the sliding frame if you intend to drill a well at the suburban site. In this instance, let’s examine formwork installation in more detail.
An innovative technique in construction known as sliding formwork makes it possible to pour concrete continuously and effectively for tall buildings, bridges, and silos. With this method, a moving form is poured into the concrete and is guided by a hydraulic jack system to rise steadily. When compared to conventional methods, the outcome is a seamless, robust, and smooth surface that requires a lot less time and labor during construction. Sliding formwork is a common option in contemporary construction because it is perfect for projects that require consistency and speed.
Making formwork for a well
A well’s frame can be constructed by you or you can rent a pre-made form.
The following scheme is used to make half rings for do-it-yourself sliding formwork.
If required, the earthworks can be reduced by 20% by making the inner ring 10 cm smaller.
It is preferable to use metal sheets with a thickness of 1-1.5 mm for such a design; if you use a thinner material (like 0.8 mm), the formwork won’t be sturdy enough. Excessively thick sheets (greater than 1.5 mm) will consequently cause the structure to ponder greatly.
Practical! In order to prevent the concrete mortar from being "caught," fasteners should not be inside. It is preferable to remove all fasteners.
Bars about 20 mm thick must be installed between the semicircle sheets to keep them from moving when the formwork is released. Additionally, the following needs to be ready:
- 12 "distance" bars about 9.5 cm long (they will be located between the outer and inner walls of the structure).
- 2 crosses (as in the picture below), with which you can give the formwork the correct cylindrical shape. To make a cross, just connect two boards with a cross and fasten them with a bolt.
You ought to obtain such a structure as a result.
Installation of formwork for a well
The best time to drill a well is thought to be between August and October, when the groundwater table falls.
Prior to putting in the formwork and pouring the concrete, you must get ready:
- Bottom filter. To do this, you need to fill the bottom of the well with a layer of sand and crushed stone (the thickness depends on the groundwater level and terrain features).
- A section for pumping equipment (if it is supposed).
- A layer of waterproofing made of roofing felt or ordinary thick film.
Additionally, the frames are affixed at the well’s base, where the jacks are secured.
The following technology will be used to install the formwork:
- Assemble the formwork and lower it into the pit.
- Install the upper and lower crosspieces.
- Place 6 "spacer" bars between the outer and inner walls (top and bottom).
- Adjust the formwork by plumb line so that it is in a vertical position.
- Mix cement M 400 (or higher) and sand in a ratio of 1:4, add water and crushed stone so that the solution is mixed with difficulty.
- Install longitudinal and transverse reinforcement in the formwork (you can use steel rods or ordinary wire).
- Pour a layer of concrete about 30 cm high and compact it with bayonets.
- Remove the spacer bars.
- Wait until the walls of the first tier gain initial strength, and begin to raise the formwork structure by 2.5 cm every 10 minutes.
Thus you can create a reasonably quick well with the aid of movable formwork.
Practical! There are those who suggest installing a "concrete knife" beneath the well’s first ring. The diameter of the knife should be marginally greater than the ring itself. This makes the process of lowering completed rings easier. But installing a "knife" is extremely difficult, requires more excavation work, and increases the chance that the well’s walls will start to veer vertically.
Other objects can be concretized in a similar way.
In the construction industry, sliding formwork is a revolutionary technique that makes it possible to pour concrete continuously and efficiently to build tall structures. When building silos, high-rise buildings, bridges, or other vertical structures where traditional formwork might be too time-consuming or impractical, this technique is crucial.
The capacity of sliding formwork to save time and lower labor costs is one of its main benefits. It does away with the necessity of several steps for assembling and disassembling forms by permitting a continuous and uninterrupted pour. This guarantees a more even and consistent finish on the concrete surface in addition to accelerating the construction process.
Sliding formwork also improves safety on building sites. Accident risk lowers when fewer workers are required for form setting and removal. A safer working environment is also promoted by the sliding formwork equipment’s design, which offers workers stable and secure platforms.
Sliding formwork can have a more complicated initial setup that takes skilled labor, but the long-term advantages make the investment worthwhile. Sliding formwork is an essential technique in modern construction due to its capacity to ensure higher quality outcomes, improve efficiency, and streamline construction processes.
In conclusion, sliding formwork is a major development in building technology. It gives builders of tall structures a quicker, safer, and more affordable option by permitting continuous concrete pours. Sliding formwork will probably become more crucial in forming our cities’ skylines as the construction sector develops further.
