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General properties of the Joist floor slabs (generic concrete joists) module of CYPECAD
Using the Joist floor slabs (generic concrete joists), generic concrete joist floor slabs can be analysed and designed. This is very useful when the user does not know beforehand which type of joist floor slab will finally be used on site. Therefore, the results provided only display the forces in the joists. The user initially has to select whether the joist to be introduced will be a reinforced or prestressed joist so the deflection may be calculated adequately.
Definition of generic concrete joist floor slabs
The user defines the floor slab to be used by providing the following parameters:
- Geometry
- Compression layer thickness
- Form depth
- Rib spacing
- Rib width
- Longitudinal width
- Rib width increment
This increment is defined to take into account the thickness of partitions within the forms when calculating the stiffness and cracking moment required to obtain the deflection.
These partitions are taken into account, as do the main manufacturers of precast joists. If they are not considered (value 0), the deflection provided by the program for generic joists would always be greater to that provided with an equivalent reinforced or prestressed joist floor slab of a particular make.
The values of this rib width increment depend on the type of lightweight form. The following values are recommended:
- Concrete form: 3 cm
- Ceramic form: 0 cm
- Polystyrene form: 0 cm
- Removable form: 0 cm
- Design data
- Concrete volume
The program calculates the approximate volume of concrete per unit surface area bearing in mind the geometrical parameters that have been introduced, displaying the updated result for these parameters.
Nonetheless, if the user wishes to introduce a surface volume different to that proposed by the program, the value can be modified.
The user must take into account that the value displayed by the program, or that introduced by the user, corresponds to that of a floor slab consisting of single joists. If double or triple joists are to be used, the program calculates the corresponding volume depending on the geometry that has been introduced.
- Type of form
The user selects the material of the form (concrete, ceramic or polystyrene) and the program calculates the approximate surface weight of the floor slab, taking into account the geometrical parameter that have been introduced and the chosen material.
If the user wishes to provide a different value for the surface weight, it can be done by selecting a generic material for the form and indicating the desired value.
The user must take into account that the value displayed by the program, or that introduced by the user, corresponds to that of a floor slab consisting of single joists. If double or triple joists are to be used, the program calculates the corresponding volume depending on the geometry that has been introduced.
- Deflection check
In the Panel manager dialogue box, the user initially selects whether the joist floor slab is going to consist of reinforced joists or prestressed joists. Here, the user can change the type of joist floor slab from reinforced to prestressed and vice-versa. If the user changes to another type of joist, all the panels using this specific generic joist will change to this new type. The program will carry out the deflection check based on the approximate calculation of the cracked inertia of the joists. This approximation is carried out in a different manner depending on whether it is a reinforced joist or a prestressed joist.
In the case of reinforced joists, the program calculates the steel reinforcement required to resist the positive moment of the joist; and using this value, it calculates the approximate cracked inertia.
With prestressed joists, the previous approximation is not possible as the behaviour of this type of joists is completely different and the case can even arise there the cracked inertia is practically equal to the gross inertia, due to the effect of prestressing the joist. In this case, the program allows the user to introduce the value of the cracked inertia as a percentage of the gross inertia. After consulting manufacturer property tables, this value usually oscillates between 50% and 100%.
For both cases, the gross section of the joists are calculated based on the geometrical parameters that have been introduced and the assuming the constant rib widths, with slight increments at the intersection with the compression layer.
Library of generic concrete joist floor slabs
Users can save the data of the generic joist floor slabs they have created or received from other clients.
The program has a series of analysis options available with adequate default values which the user can configure (Minimum lengths of top reinforcement, minimum moments to cover with reinforcement, cover, rounding of bar lengths…)
After the analysis of a structure containing generic concrete joist floor slabs, the program displays the following results:
- Bending moments with an applied safety coefficient and shown per metre length
- Shear forces with applied safety coefficient and shown per metre length at support edges
- Top reinforcement
CYPECAD versions
CYPECAD is available in its unlimited version and also in two limited versions called LT30 and LT50, which contain the same tools and module acquisition possibilities, but have the following conditions:
CYPECAD LT50:
- Fifty columns
- Four floor groups (Floor group: floors which are the same and consecutive)
- Total of five floors
- Walls: one hundred linear metres
CYPECAD LT30:
- Thirty columns
- Four floor groups (Floor group: floors which are the same and consecutive)
- Total of five floors
- Walls: one hundred linear metres
Integrated 3D structures of CYPECAD (also LT50 and LT30) is not technically a module. To define these 3D structures in CYPECAD, users must also have the required permits to use CYPE 3D in their user license and, optionally, modules which are exclusive to CYPE 3D.
CYPECAD Modules
The following modules are those that can be acquired together with CYPECAD or CYPECAD LT:
- Steel columns
- Steel beams
- Joist floor slabs (generic concrete joists)
- Joist floor slabs (in-situ, precast and steel)
- Timber joist floor slabs
- Waffle slabs
- Flat slabs
- Punching shear verification (Also operates as an independent program)
- Composite slabs
- Hollow core slabs
- Post-tensioned concrete slabs for buildings
- Shear walls
- Reinforced concrete walls
- Plane stress walls
- Stairs
- Mat foundations and foundation beams
- Concrete block walls
- Interaction of the structure with the construction elements
- Automatic job introduction: DXF, DWG and CAD/BIM models
- Collective protection systems
Modules common to CYPECAD and CYPE 3D:
- Concrete columns
- Composite steel and concrete columns
- Concrete beams
- Timber sections
- Pile caps (includes strap and tie beams)
- Baseplates
- Footings (pad and strip) (includes strap and tie beams)
- Advanced design of surface foundations
- Fire resistance check
- Parallel analysis with two multiprocessors
- Parallel analysis with up to eight processors
- Joints I. Welded. Warehouses with rolled and welded steel I sections
- Joints II. Bolted. Warehouses with rolled and welded steel I sections
- Joints III. Welded. Building frames with rolled and welded steel I sections
- Joints IV. Bolted. Building frames with rolled and welded steel I sections
- Joints V. Flat trusses with hollow structural sections
- Export to Tekla
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