Versione 2014.c

Code implementation and improvements in its application. CFE 2008 (Mexico) and NTC 2004 (Mexico)

• CFE 2008 (Mexico)
  Manual de Diseño de Obras Civiles. Diseño por Sismo
• NTC 2004 (Mexico)
  Normas Técnicas Complementarias para Diseño por Sismo
  

These codes were already implemented in CYPECAD and Metal 3D as of previous versions. Now, in the 2014.c version, CYPECAD offers two options to indicate the value of the Fundamental period of the structure (used to calculate the base shear):

• In accordance with the code (only way possible in previous versions)
• User specified (implemented in the 2014.c version)

More information can be found in the section on: “Seismic analysis. Fundamental period of the structure with user values for CFE 2008 and NTC 2004 Mexican design codes” in the new features of CYPECAD of this webpage.

Code implementation and improvements in its application. CIRSOC 103-2005 (Argentina)

Normas Argentinas para Construcción Sismorresistente. Parte II: Construcciones de Hormigón Armado.

This code was already implemented in CYPECAD as of the 2013.l version in order to be able to use the Reinforcement ductility criteria and the Capacity design criteria for seismic design which are to be used with the concrete code: CIRSOC 201-2005 (Reglamento Argentino de Estructuras de Hormigón).

Now, for the 2014.c version, the following checks have been included:

• Compliance with article 2.2.9.2
• For the capacity check of concrete columns, the design axial force specified in article 2.3.5 is used

Please recall that users do not select the CIRSOC 103-2005 code to be applied. The combination of the CIRSOC 201-2005 concrete code together with seismic code CIRSOC 103-1991 (current seismic code in force in Argentina) or together with seismic code CIRSOC 103-2008 (project seismic code which will substitute CIRSOC 103-1991) implies the reinforcement ductility criteria and capacity design criteria for seismic design of CIRSOC 103-2005 be applied.

Seismic analysis. Fundamental period of the structure with user values for CFE 2008 and NTC 2004 Mexican design codes

CYPECAD allows users to define the Fundamental period of the structure (used to calculate the base shear) in two ways:

• Based on the code (only way possible in previous versions)
• Specified by the user (implemented in the 2014.c version)

Either of the two options can be selected in the section Estimation of the fundamental period of the structure within the Code for the calculation of seismic loading dialogue box (General data ˃ Select “with seismic loading” from the “Loads” section ˃ select Mexico as the country and CFE 2008 or NTC 2004).

The value of the fundamental period of a building must be obtained based on the properties of its seismic resistance system, in the direction being considered, in accordance with structural dynamic principles. Alternatively, most seismic codes allow for the fundamental period to be estimated:

• Using empirical formulas provided within their articles
• Using other methods, as long as these are adequately sustained analytically or experimentally

The estimated fundamental period is applied in the calculation of the static shear at the base of the structure (base shear) which:

• Adjusts the dynamic results to minimum values prescribed in the code, if the dynamic method is applied
• Generate the distribution of the equivalent static lateral forces, if the static method is applied

Article 3.3.5.1 of the CFE 2008 code establishes the calculation of the base shear force by taking the bottom period limit of the plateau of the design spectrum (Ta) as the estimated fundamental period; and article 8.1 of the NTC-2004 code takes any period which coincides with the design spectrum plateau (Ta ≤ T ≤ Tb).

The indicated values are limits established in the codes that can be used in the absence of more precise data. If users have values of the fundamental period which are more adjusted to their structure (calculated using their methods or using software such as CYPECAD, which calculates the fundamental period of the structure in each direction – the values can be consulted after the analysis in the “Justification of seismic action report”: File ˃ Print job reports), they may specify them by selecting the Specified by the user option, located in the Code for the calculation of seismic loading dialogue box, as has been indicated previously.