The foundation device provides for the creation of formwork. This is a molding structure into which a sand-cement mortar is poured. Usually it is built of wood, and recently the technology of expanded polystyrene frame, which performs the same function, but at a higher technical level, has begun to spread. In turn, metal formwork is far from the most practical solution for building a foundation, but in some cases it also justifies itself.
Technology Overview
Due to the complexity of installation and transportation measures, when organizing the construction of such a formwork, it is rarely used. Therefore, it is collected with the expectation of repeated use in the future. As for compatibility with different types of foundations, there are practically no restrictions - moreover, metal theoretically turns out to be a more universal option for setting the mold under concrete mortar than wood. In practice, metal formwork is used in the construction of columnar, pile, slab foundations, but the most popular is strip. In particular, such a foundation is used in the construction of low-rise residential buildings. Platforms for high-rise buildings are arranged mainly on slab foundations with a metal supporting structure.
Formwork material
It is not at all necessary to use high-strength alloys - like wood, sheet metal copes well with the holding function in relation to concrete pouring. Both steel and aluminum can be used. This choice will be determined to a greater extent by the type of formwork - removable or non-removable. In the first case, it is desirable to use steel elements, and in the second, there will not be much difference. Unless you have to consider the weight of the structure. The installation of heavy metal formwork for the foundation with subsequent dismantling does not make sense from the point of view of operational value. Another thing is that the features of the configuration of the bearing form may make it impossible to use aluminum and wood with polystyrene. Also, in addition to the metal base, the construction device will require fasteners, fittings and various kinds of clamps for the possible laying of communications.
Types of formwork designs
There are several options for the structural execution of a metal mold for the foundation. As a rule, small and large-panel constructions are distinguished, as well as a permutable model. In the first two cases, the shield acts as the main element of the assembly. In a small-panel formwork , a frame of complex geometry is formed, which makes it easy to integrate auxiliary functional parts for insulation, mounting inserts for grillage, etc. Large panels for metal formwork are involved in large-scale projects, where the requirements for the bearing capacity of the foundation frame come to the fore. As for the interchangeable system, thanks to the possibilities of changing the shape and configuration, it makes it possible to erect non-standard architectural structures.
Formwork
The main workflow is the layout of the skeleton formwork of the above shields. Usually steel elements 1.5-2 mm thick are taken. In the case of aluminum, the thickness increases to 5-6 mm. At this stage, it is important to form the main formwork body, which will then be laid in the place prepared for installation. Assembly is carried out using anchor joints, bolts, studs and a tube sleeve. Thanks to the latter, two shields are brought together with a distance of 30-50 cm being maintained. At the stage of manufacturing metal formwork, it is important to observe equal gaps between the shields along their entire length. It is in this free space that concrete will be poured. In order to strengthen the structure, you can use the side corner, welding the sides of two modules to it. This is done with respect to steel panels, and soft aluminum can be further strengthened by bolting, introducing transverse ties into the structure.
Design installation
Under the finished formwork, a trench 50-70 cm deep is created. The fabricated frame will be placed in it, but before that it is necessary to establish a reliable base. At the bottom is a thick metal platform, followed by reinforcement with frame beams. And already on this basis, the installation of metal formwork on a shield basis is carried out. At this stage, lateral struts are installed for reliable fixation of the shields, and in the upper part are mounted string wires - surface elements to hold the structure for the period of solidification of the mortar. It is very important to provide in the design and PVC pipes to create through holes for ventilation. Using the same devices, circuits for laying communications are arranged. They are fastened with clamps or welded hinges in the place where engineering contours pass. At the final stage, concrete is poured for the foundation. The polymerization time of the structure is an average of 15-20 days.
Technology advantages
Like all metal structures, against the background of wooden structures, such a formwork wins in strength and bearing capacity. If you use it in a non-removable design, then durability will also be added to the durability. In this criterion, it is possible to compare metal formwork with polystyrene, but the operational effect will be approximately the same. The fundamental difference is in size (steel panels are thinner and take up less space) and form factor (polystyrene is more diverse in output formats). If you touch on the issue of savings, then the metal will cost a little more expensive than wood, but much cheaper than plastic elements.
Cons of technology
It’s worth starting with organizational troubles, since in any case, delivery of the assembly in assembled or disassembled form will have to be carried out with the connection of special equipment. The same goes for installation. Large shields without special equipment or movable equipment cannot be installed. The installation of aluminum metal formwork is noticeably simplified, but this option has significant limitations in terms of the choice of ways of strengthening and joining with reinforcing elements. If necessary, both thick and thin rods can be welded to a steel shield surface, but in this case it will be necessary to use expensive welding of anodized aluminum, which is not always financially beneficial.
Conclusion
The use of metal for concrete pouring of the foundation is often justified when installing fixed formwork. In such a model, the dismantling of panel elements is not required and one can count on the long-term operation of a solid supporting base for the home. Only a more functional polystyrene can compete with this approach with lightweight modular units that can be installed without special mounting hardware. The removable metal formwork should be used in projects where it is planned to arrange a foundation of a large area. Especially in structurally complex systems, wood may not endure the loads that metal can handle. Further, when the flooded base gains sufficient strength and hardens, the boards can be safely removed. In the future, the operational properties of the structure will depend only on the quality of the concrete mix used.