We always look at the total cost and effectiveness of a project, where the work on-site is minimized. Compared to competing products, the SWT system is very fast to assemble and erect. The SWT composite beam, for instance, can be filled with concrete in a minute or less. The lack of need for temporary beam supports during erection of the floors is another advantage that saves our customers time and on-site costs.
Our composite products are also fire resistant up to R90 without any external protection, and the sound isolation properties are comparable to that of solid concrete.
The quick and easy erection of a steel frame,
combined with the fire resistance, strength and noise isolation
of a classical concrete construction.
Our composite products consists of hollow steel beams and columns which are cast with concrete at the same time as the floor slab joints. Little to no forming is necessary while casting, since the products are hollow and provides their own mold. This allows a quick and easy erection of the floors, with erection times comparable to simple steel frames.
The products are generally a lot slimmer than concrete constructions, and in the case of the SWT beam, even less obtrusive than conventional steel. At the same time, they retain many of the benefits of concrete, including fire resistance and excellent noise isolation.
The strength is far greater than steel-only products of comparable size. In fact, few products can match composite constructions in strength-to-size ratio, which means they are very suitable for solutions with long spans and large loads. As an example, a 500mm high SWT beam can have twice the strength of an HEA500, and more than three times the strength of an IPE500.
Our composite beams are so called slim-floor beams and are hidden in the floors, with only the supporting flange visible*. This allows for greater freedom when designing the interior of the building, compared to a solution where the slabs rest on top of the beams.
The beam consists of a steel U-profile which is welded to the lower flange. The upper flange is perforated to allow casting with concrete on site. Since the holes are in the top of the beam, the casting is very quick with no need to wait for air to escape; a beam can typically be filled in less than a minute.
The upper flange is strengthened by steel bars that are welded to the side of the perforations, and the excess steel from the perforated flange folds into the beam and acts as shear connectors. If constructive concrete is used on top of the floors, it is possible to achieve even greater composite action with the beam by inserting reinforcement into the open holes in the top during casting. A wider active composite section will allow for higher strength of the entire floor slab.
*In some cases, the SWT beam can be made higher than the floor thickness, which means that it will extend a bit below the floors. This way, we can produce beams with strength rivalling that of the most massive concrete beams.
The inside of the beam contains reinforcing steels, which strengthens the lower part of the beam in case of fire. Load bearing criterion R90 is usually achievable without any external protection.
The concrete-filled beam doesn’t contain any air pockets, which makes it a good sound insulator. This is supported by measurements** performed by “Stålbyggnadsinstitutet”, SBI.
**SBI rapport nr 160:1 “Ljudisolering i bjälklag bestående av stålbalk och håldäckselement” and SBI publikation nr 144 “Ljudisolering i bostadshus med stålstomme”.
The SWT composite column consists of a circular or square steel tube with a solid steel core in the center. Concrete is cast in the space between, after the beams and floor slabs are mounted. The concrete reaches the column through the SWT beam via a hole in the lower flange.
The tube works as a mold for concrete casting and provides a durable and smooth, paint friendly surface.
The steel core transfers vertical forces and increases the capacity of the column. It protrudes through the beam and creates a support stud in the next floor, assisting in placement of the next level of columns.
The top plate is used as support for the beams and concrete floor slabs. The forces are transferred via the top plate into the entire column (concrete and steel parts). The force component in the steel core is transferred through the entire construction by direct contact.
Standard outer dimensions: Ø159, Ø219, Ø273, Ø323, Ø406 and Ø508mm circular, and 150x150mm, 200x200mm, 250x250mm, 300x300mm square. The diameter of the steel core varies depending on tube and desired strength.
The column can be designed for load bearing criterion “R” in fire situations, up to R120 in some cases, assuming that the column is filled with concrete.
Steel products are the backbone of modern construction,
something that we at SWT are very good at.
We both design and manufacture what you need.
We provide steel products made of conventional profiles like HEA, IPE, UPE, round- and rectangular hollow sections and solid bars, among many others, and we modify them with stiffeners, connections and pre-cut holes, to ensure optimal performance and ease of assembly.
We also make custom products, both build-up welded beams and truss works, and folded steel profiles. Our cold formed profiles can be made with continuous lengths of up to 8m, and thickness up to 10mm*. An ideal usage is as loadbearing eaves beams for panel roofs on steel halls, or as our façade Z- and C-profiles.
All our steel products can be designed by us from scratch, but we also regularly manufacture on given dimensions, and even from finished shop drawings, when that is desired. If you’re unsure of what you need, give us a call!
*Possible thickness depends on the desired radius
Two types of folded façade beams exists, both of which are higher than the floor slabs. This means that they work as side molds for the floor casting. They are easy to assemble, and comes with either screw joints or welded joints.
The Z-profile is strengthened by a steel bar and is used for single-sided support of floor slabs. The beam is intended to be built into the wall, which helps during assembly of the floor slabs. The lower flange is sometimes visible after the walls have been assembled (depending on wall position and thickness), and may have to be protected to reach the desired load bearing criterion in fire.
The only thing changing in the picture below is the height; the material thickness and the width of the lower flange (slab support) is the same. Three heights are available: 250, 300 and 360mm.
The C-profile works in the same way as the Z-profile, with the only difference being that it disappears completely into the wall after assembly. The need for extra fire protection is therefore eliminated.
The only thing changing in the picture below is the height and material thickness; the width of the upper and lower flanges are the same. Three heights are available: 220, 260 and 300mm.
The column consists of a square or rectangular hollow section, and is used to carry the façade beam which is bolted or welded in to the support.
The length can be adjusted to one or several floors, and the column is made to fit inside the wall.
The desired fire resistance can be reached by covering the column with protective insulation materials, like rockwool panels or fire retardant paint.
SWT has developed a support ring to aid in the assembly through minimization of the need for on-site welding.
The support ring fits the round SWT’s composite columns, and consists of two halves which are clamped together using two M16 bolts. Two struts are fastened in the ring with M16 bolts, and are spread at a 90° angle to support the column in both directions.
The support rings can be reused on the next floor once the casting on the current floor is done. Therefore, the total amount needed corresponds to how large parts of each floor is erected in one go, before casting and moving on.