Design calculation of weight reduced concrete slabs

Since 2016, Heinze Cobiax Deutschland GmbH has been part of the Heinze Group, a group of leading companies from plastics technology which are active both nationally and internationally. Over the course expansion, Cobiax is now intensifying its service, amongst other things through the update and extension of the Cobiax software tool Quick & Light, which is available free of charge to download in the latest Version

Free design aid for ­structural calculations

Because a Cobiax voided slab is planned and designed in accor-dance with the standard and the general building approval in just the same way as a conventional reinforced concrete slab, complex verifications as a ribbed or waffle slab are rendered superfluous.

The Cobiax software tool Quick & Light offers the convenient possibility of simple determination and the inspection of the cross-section structure as well as the determination of the relevant Cobiax-specific input parameters, such as load reduction, stiffness factor and shear factor or the reduced shear resistance.

Using these values, the structural calculation of a Cobiax voided slab can be done with any structural calculation program. Supplementary to the reduction of dead weight, the stiffness factor and the shear factor, the concrete reduction through the plastic void formers and the reduced shear resistance of the Cobiax voided slab can be calculated using the software tool Quick & Light. In addition, the transfer of horizontal shear forces in the joint with reduced bonding area can be verified, as in practice, the concreting to protect against uplift of the void former modules takes place in two working steps. This is unnecessary in a design as semi-prefabricated element.

The software is available in the languages German, English and French and takes the following standards into account: EC2 (DE), EC2 (EN), SIA 262 and the ÖNORM (Austrian Standard) B4700.

During the course of updates, the “Slim-Line” product line has been replaced by the new “Slim-Line-Click” product line, and has been supplemented through additional void former sizes. With the “Slim-Line-Click” product line particularly slim line concrete slab constructions can be realized from a thickness of 20 cm. In this product line, void former modules for slab thicknesses up to 56 cm are offered. All relevant calculation parameters for this “Slim-Line-Click” product group are filed in the Release

Executed up to a R240 fire resistance duration

At the same time, the complete fire protection verification was revised and the database updated based on the new FEM calculations. The verification can take place in accordance with the general building approval or based on expert’s reports.

So that a Cobiax voided slab offers the identical safety level as a completely solid reinforced concrete slab in case of fire, the design concept and the software-supported calculation are based on the requirements laid down in the DIN EN 1992-1-2. For the verification of fire resistance, the temperature is determined in the statically-effective flexural reinforcement acc. DIN EN 1992-1-2, taking the cross-section geometry into account. This temperature may not be higher than the temperature of the reinforcement steel in a completely solid reinforced concrete slab with the same fire resistance duration. The new program version Quick & Light inspects the products, taking into account the cross-section geometries selected, to see whether the required fire resis-tance duration can be achieved.

In accordance with the general building approval, Cobiax voided slabs can be executed up to a R240 fire resistance duration.