D8.A.7 Seismic Detailing per Section 12
Seismic detailing of steel members per portions of Section 12 of IS 800-2007 can be performed by STAAD.Pro for LSD design.
The program will check seismic detailing requirements when the design parameter
SEISMIC
(design detailing for earthquake load) has been specified as 1.
It is also recommended that an IS 1893 seismic load definition is included in the
model.
- 1.2×DL + 0.5×LL + 2.5×EL
- 1.2×DL + 0.5×LL - 2.5×EL
- 0.9×DL + 2.5×EL
- 0.9×DL - 2.5×EL
LOAD LIST
may be used.
Otherwise, the checks for Section 12 will be done for all load cases and
combinations.Among the various seismic criteria present in the section 12 of IS800:2007 only
compression and tension strength and slenderness are considered as a failure criterion.
Detailed output of the seismic checks are provided only for TRACK 2
output. Other TRACK
options will only report a seismic provision if it
is the critical clause for member checks.
Limitations
As the design checks are performed on analytical members (rather than physical
members), there are no means by which to ensure provisions of Cl. 12.5.1.2 (i.e.,
the strong column, weak beam
design philosophy) are met. That is left to the
engineer. Similarly, code checks which require comparison of one member's strength
to another are not possible in design checks under STAAD.Pro.
Applicable Code Sections
- 12.2.1 - the R values are derived from the specified frame type. If this differs from the R values manually specified in the seismic load definition, a warning is presented in the output. If the assigned R in the local Z and local Y differs, the program will consider the minimum R.
- 12.2.3 - the IS 800 load combinations should be manually added or included from automatically generated load combinations
- 12.3 - the frame type is specified by use of the
SSY
andSSZ
parameters - 12.5.1.1
- Ordinary concentrically braced frames
- 12.7.1.1 - limits the use of OCBFs in seismic zones IV and V, as well as in seismic zone III when the importance factor is greater than one
- 12.7.1.2 - the bracing type used in the model should be
consistent with the
SSY
andSSZ
parameters specified. Members used as bracing should also be specified using theIMM
parameter. - 12.7.2.1
- 12.7.2.2
- 12.7.2.4
- 12.7.2.6
- Special concentrically braced frames
- 12.8.1.1
- 12.8.1.2 - the bracing type used in the model should be
consistent with the
SSY
andSSZ
parameters specified. Members used as bracing should also be specified using theIMM
parameter. - 12.8.2.1
- 12.8.2.2
- 12.8.2.3
- 12.8.2.5
- 12.8.2.7
- 12.8.4.1
- 12.10.1.1 - Ordinary moment frames shall not be used in seismic zones IV and V, as well as in seismic zone III when the importance factor is greater than one
- Special moment frames
- 12.11.1 - checks the material grades assigned (i.e, the
FYLD
andFU
parameter values assigned) are equal to or higher than grade E250B. - 12.11.1.1
- 12.11.3.1
- 12.11.1 - checks the material grades assigned (i.e, the