CYPECAD

As of previous version, the anchorage length of the columns at the last floor and the splice length at other floors could be reduced. Now, with the 2014.d version, users can reduce the length of only bars that are in tension, in which case, a minimum resultant length for bars in tension has been established as Lb (basic anchorage length). This way, the anchorage lengths and splice lengths (if the reduction is also applied to floors below the last floor) will be more uniform.

To implement this new option, the “Reduction of anchorage lengths in columns” dialogue box now contains a new option: “Only for bars in tension”. This option can be activated separately for the last floor and for floors below the last floor.

In previous versions, users could only introduce one axial stiffness coefficient for all the reinforced concrete columns, shear walls and walls of the job. As of the 2014.d version, three generic axial stiffness coefficients exist which can have different values:

• Axial stiffness coefficient for columns
• Axial stiffness coefficient for shear walls
• Axial stiffness coefficient for walls (reinforced concrete walls and plane stress walls )
  
  

As well as the three generic axial stiffness coefficients, the 2014.d version of CYPECAD also allows for specific axial stiffness coefficients to be assigned to each column, shear wall, reinforced concrete wall or plane stress wall of the job.

An axial stiffness coefficient can be assigned to these elements with a different value at each span, following the process detailed below:

• For columns
  The individual axial stiffness coefficients are assigned to each column (Column Definition tab > Introduction > Columns, shear walls and starts > Axial stiffness coefficient > select a column > select “Column properties which differ from the general properties of the job” > Introduce the axial stiffness coefficients for each floor).
  
• For shear walls
  The axial stiffness coefficients for shear walls are assigned to each shear wall type, which implies that all the shear walls of the same type that are introduced will have the axial stiffness coefficients for that type (Column Definition tab > Introduction > Columns, shear walls and starts > Edit > select a shear wall > Define types > select “With different axial stiffness coefficient” > introduce the axial stiffness coefficients for each floor).
  
• For reinforced concrete walls and plane stress walls
  The axial stiffness coefficients for walls are assigned to each wall span that is introduced in a single introduction step (Beam Definition tab > Beams/Walls > Edit > select a wall span > select “With different axial stiffness coefficient” > introduce the axial stiffness coefficients for each floor).

CYPECAD now allows users to apply reduction coefficients to the concrete resistance for each column span that is selected. This is possible with codes which can use the advanced column editor.

These coefficients are defined using the Concrete resistance option (Column Definition tab > Introduction > Columns, shear walls and starts). A column is selected using the left mouse button, after which a dialogue box appears on-screen where users can:

• If the Job general data option is activated, user can:
  • View the type and general concrete reduction coefficients of the job
• If the option: Reduce the concrete resistance is activated, users can:
  • View the type and general concrete reduction coefficients of the job
  • Introduce concrete resistance reduction coefficients for each column span
  • Modify the concrete resistance reduction coefficient at the required spans

This allows users to define the design resistance of the concrete for each column span if any tests have been carried out indicating the concrete has a low resistance.

Using the “Copy” option of the “Columns, shear walls and starts” dialogue box (Column Definition tab > Introduction > Columns, shear walls and starts), the program allows for the properties of a selected column to be copied to another that has already been introduced. Amongst the properties that can be copied are the reduction coefficients of the column selected as the model column, if the Concrete resistance option is activated in the dialogue box that appears when the column is selected.

A new option has been implemented whereby users can define a different maximum aggregate size for each type of element: floor slabs, foundations, columns or walls (Job ˃ General data ˃ Aggregate properties in the reinforced concrete section).

Additionally, when the concrete EHE-08 (Spain) or ABNT NBR 6118 Projeto Junho 2013 (Brazil) codes are used, the nature of the aggregate can also be defined, with different values for floor slabs, foundations, columns or walls if users indicate it so. These design codes contain a correction coefficient of the longitudinal deformation module of the concrete, which depends on the nature of the aggregate used for its elaboration.

Using the EHE-08 code, the following aggregate nature types can be selected in accordance with that indicated in Table 39.6 (belonging to the comments of article “39.6. Módulo de deformación longitudinal del hormigón”):

• Cuarcita
• Arenisca
• Caliza normal
• Caliza densa
• Ofita basalto y otras rocas volcánicas - Poroso
• Ofita basalto y otras rocas volcánicas - Normal
• Granito y otras rocas plutónicas
• Diabasas
  

In the EHE-08 design code, the correction coefficient of the modulus of elasticity of the concrete is contained within the comments of the code, and so it is not obligatory for users to comply with it. When the nature of the aggregate is quartzite (cuarcita), the correction factor of the elasticity modulus has a value of 1, and this would be the option to be used if the reduction factor is not to be applied or, obviously, if this is the real nature of the aggregate that is used.

Using the ABNT NBR 6118 Projeto Junho 2013 code, the following aggregate natures can be selected as indicated in article “8.2.8. Módulo de elasticidade”:

• Basalto
• Diabásio
• Granito
• Gnaisse
• Calcário
• Arenito
  

Using the ABNT NBR 6118 Projeto Junho 2013 code, when a value of 1 is assigned to the correction coefficient of the modulus of elasticity of the concrete, it belongs to aggregates with “Granito” and “Gnaisse” natures.

CYPECAD, as of previous versions, takes into account the capacity design criteria of concrete beams and columns, for specific codes when undertaking the seismic analysis of the structure .

The geometric and mechanical properties of the columns and beams are automatically contemplated with the capacity checks (as of previous versions) as are, optionally, the properties of the floor slabs bearing on beams reaching a column (as of the 2014.d version).

To define the geometric and mechanical properties of the floor slabs, with regards to the capacity checks for concrete beams and columns, a new option has been implemented in the program: Assign data for the capacity check (Beam Definition tab > Beams/Walls).

The aforementioned option will only be visible if a seismic analysis is carried out with a design code which has the capacity check implemented for CYPECAD .

When this option is activated, a dialogue box appears where users can define the following data:

• Effective width (1)
• Effective width (2)
• Effective depth (3)
• Mechanical steel area of the top reinforcement
• Mechanical steel area of the bottom reinforcement

Users can assign them freely to any side or end of beams reaching columns. This way, slabs which have different geometric or mechanical properties at either side of the beam, or beams which only have the floor slab on one side can be contemplated.

To identify each of the sides and ends of the beam to which the data has been assigned for the capacity checks, the program displays small magenta triangles at these zones, which are displayed when the option Assign data for capacity check is selected. The triangles will be displayed in green at zones where the properties of the slab have not been assigned, in which case, the dimensions and steel areas of the slab will not intervene in the capacity checks for the concrete beams and columns.

When either of these codes is used in CYPECAD (NSR-10 (Columbia) and NC 46:1999 (Cuba)), there are two options to indicate the value of the Fundamental period of the structure (used to calculate the base shear):

• Based on the code (only possibility in previous versions)
• Specified by the user (implemented in the 2014.d version)

Both options can be selected in the Estimation of the fundamental period of the structure section in the Code for the calculation of seismic loading dialogue box (Job ˃ General data ˃ select “With seismic loading” in the “Loads” section ˃ select Columbia or Cuba as the country and the NSR-10 or NC 46:1999 codes respectively).

The value of the fundamental period of a building must be obtained based on the properties of its seismic resistant system, in the direction under consideration, in accordance with structural dynamics principles. Alternatively, most seismic codes have other procedures to estimate the fundamental period:

• In accordance with empirical formulas provided in their articles
• In accordance with other methods, as long as they are adequately sustained analytically or experimentally

The estimated fundamental period is applied in the static shear analysis at the base of the structure (base shear) to adjust the dynamic results to the minimum values prescribed in the codes, when the dynamic method is applied, and to generate the equivalent static lateral forces when the static method is applied.

The values indicated by the codes are limits that can be applied in the absence of more precise data. If users have fundamental period values, which are more adjusted to their structure (calculated using other methods or with software tools such as CYPECAD, which calculate the fundamental period of the structure in both directions – the values can be consulted after the analysis in the “Justification of seismic action” report: File ˃ Print > Job report) they can specify them using the option Specified by the user located in the Code for the calculation of seismic loading dialogue box.

The 2014.d version of CYPECAD includes the reinforcement ductility criteria and the capacity design criteria when they are combined in the same analysis with the Eurocode 2 concrete codes: Eurocode 2 (EU), Eurocode 2 (France), Eurocode 2 (Portugal) with their corresponding seismic codes.

More information on the combined use of these concrete and seismic design codes can be found in the Eurocode 2 (EU, France and Portugal) section on this webpage.

The 2014.d version of CYPECAD allows users to use the advanced beam editor with the Eurocode 2 concrete codes (Eurocode 2 (EU), Eurocode 2 (France – which includes the National Application Document for France), Eurocode 2 (Portugal – which includes the National Application Document for Portugal)) combined with their corresponding seismic codes.

The ductility reinforcement criteria and capacity design criteria are also included and are indicated in the seismic codes that are compatible with Eurocode 2 (EU), Eurocode 2 (France) and Eurocode 2 (Portugal) as is indicated in section: “Eurocode 2 (EU, France and Portugal)” on this webpage, where more information can be found on the combined used of these concrete and seismic codes.