Check the story drifts due to static and dynamic loads in a spreadsheet
format table.
"Story Shear Force Ratio" in "Model/Building/Control
Data" must be checked for this function, which is checked as
the Default.
The types of story drifts, which can be checked in Story Drift Table,
are as follows:
1. Maximum Drift
2. Drift at the Center
of Mass
3. Average Drift of Vertical
Elements at each floor
4. Drift of Selected Node
Line, which passes through a node selected by user vertically
5. Average Drift of Extreme
Nodes Lines
6. Shear Weighted Average
Drift of Vertical Elements
When "Story Shear Force Ratio>Consider Story Module" is
checked in the "Model/Building/Control
Data", accurate shear forces can be obtained for the story having
the overlapping Module.
When Modules are defined in Results > Result Tables > Story >
Define Module, the Module data is displayed
in the first column of the table.
When the ratios exceed the allowable limit, they appear in red and Irregular
is printed in the Remark.
Table Tool in MIDAS/Gen offers a variety of powerful built-in functions.
Refer to the following items for detail directions:
Data
manipulation (Add, delete, modify data, etc.)
Copy/Paste
data using clipboard
Supplementary
Table functions
Table
Sorting
Table
format setting
Auto-fit
column width
Graph
printing
Supplementary
functions by Table types
Node/Element
Table
Results
Table
From the Main
Menu select Results
> Result Tables > Story > Story Drift.
Select Result Tables
> Story > Story Drift in the Tables tab of the
Tree Menu.
From Records Activation Dialog, select the
load cases for which story drifts will be calculated.
Note
Refer to Results Table of
"Usage of Table Tool"
for the usage of Records Activation Dialog.
Record
Activation dialog box
Refer to Usage
of Table Tool and check the following data:
When Modules are not defined
Drift(X):
Story drift in GCS X-direction (Click lower left tab)
Drift(Y):
Story drift in GCS Y-direction (Click lower left tab)
Drift(Combined):
Combined story drift of both GCS X, Y-directions (Click lower left tab)
Load Case:
Unit load case/combination
Story:
Story ID
Story Height:
Story Height
P-Delta
Incremental Factor(ad): When P-Delta analysis is performed, the
incremental factor becomes 1.0 irrespective of calculation results.
Note For a story drift
used for calculating the P-Delta Incremental Factor (ad), the "Maximum
Drift of All Vertical Elements"is used. (Story drift as per "Story
Drift Calculation Method" is not used in calculating the P-Delta
Incremental Factor (ad) since the values are different depending upon
the method used.)
Allowable Story Drift Ratio
1. Maximum Drifts of All
Vertical Elements
Maximum drifts are produced for each story.
Node:
Node numbers corresponding to the maximum story drifts at each story level
Story Drift:
Incremental lateral displacement over two consecutive story levels
Modified
Drift: Incremental factor for P-Delta effect * Deflection Amplification
Factor * Story Drift * Scale Factor / Importance Factor
Story Drift
Ratio: Modified Drift / Story height
Remark:
Acceptance of story drift ratio relative to the allowable story drift
ratio
2. Drift at the Center
of Mass
Difference in lateral displacements at the
centers of mass at top and bottom ends is produced.
Drift Factor
(Maximum / Current): Maximum story drift / Story drift at center
of mass
Refer to Maximum
Drift for the remainder.
3. Average Drift of Vertical
Elements
Average story drift at a corresponding story
is produced.
Drift Factor
(Maximum / Current): Maximum story drift / Drift at the selected
node line
Refer to Maximum
Drift for the remainder.
Note
The items 3, 4, 5 & 6 are produced by right-clicking the mouse on the
table followed by selecting specific items in 'Select Calculation Method'.
4. Drift of a Vertical
Line on Selected Node
Story drifts at a user selected node and
the nodes, which are located on the vertical line passing the selected
node, are produced.
Drift Factor
(Maximum / Current): Maximum story drift / Story drift at user-selected
node
Refer to Maximum
Drift for the remainder.
5. Average Drift of Vertical
Lines on Selected Nodes
Average story drifts of building column lines
selected by the user are produced. The
column lines here should be selected at the extremities of the building
plan.
Drift Factor
(Maximum / Current): Maximum story drift / Average story drift
of the building plan extremities
Refer to Maximum
Drift for the remainder.
Context
Menu (Select Calculation Method)
Story
Drift Calculation Method dialog box
6. Shear Weighted
Average Drift of Vertical Elements
Shear forces in the vertical members are
reflected into the story drifts.
The shear weighted average drift is produced
only when the 'Story Shear Force Ratio of Member' option is applied in
Model>Building>Control data.
Story Drift:
: member shear force at story
: horizontal displacement
of each story member
Drift Factor
(Maximum / Current): Maximum story drift / shear weighted average
story drift
Refer to Maximum
Drift for the remainder.
7. Context Menu
The user provides the data for calculating
modified story drifts and P-Delta incremental factors. These
are required values for generating the table. When
Table is invoked, the set Story Drift Parameters window is executed first.
Context Menu
(Set Story Drift Parameters)
Set
Story Drift Parameters dialog box
Modify
Beta dialog box
Response Modification
Coefficient
Deflection Amplification
Factor
Importance Factor
Scale Factor:
Cm, Scale-up Factor
Vertical
Load Combination: Define a vertical load condition to consider
the P-Delta effect.
Define Beta:
Design Shear Force/Shear Capacity at a story in question, which can be
defined by the user for each story
Note
All the items other than Response
Modification Coefficient are applied
only for IBC 2000 and KBC 2005.
When Modules
are defined
The Module column is generated only when
the Modules are defined. Story drifts are calculated as per the following
Note.
Drift(X):
Story drift in GCS X-direction (Click lower left tab)
Drift(Y):
Story drift in GCS Y-direction (Click lower left tab)
Drift(Combined):
Combined story drift of both GCS X, Y-directions (Click lower left tab)
Note
Method of calculating Story Drift for each Module
Module Example
1. Story drifts for the
top floors of each Module are not generated.
2. Maximum Drift of All
Vertical Elements
Drift at 4F of A_Module (left) is the maximum
of story drifts for all the vertical elements at 4F (differences between
the displacements at 4F and 5F). Drift at 4F of B_Module (right) is the
maximum of story drifts for all the vertical members at 4F (differences
between the displacements at 4F and 6F). Drift at 4F of C_Module (base)
is not generated.
3. Drift at the Center
of Mass
1) For a
story assigned with Story Diaphragm:
The drift at 4F of A_Module (left) is the
difference between the displacement at a point on 4F, which is generated
when the Diaphragm Center (Mass Center) of 5F is projected on 4F, and
the displacement at Mass Center of 5F. The drift at 4F of B_Module (right)
is similarly calculated. A projected point on 4F is assumed to be included
in the Diaphragm of 4F when calculating the displacement.
2) For a
story without Story Diaphragm:
Average story drifts of vertical elements
are used. To consider the case when specific wall elements are divided
into smaller elements, first obtain the average drifts for each area and
then obtain an average of all the average drifts.
Ex) When 5F is assigned with a diaphragm
and 4F not assigned with a diaphragm (slab is modeled by using plate elements),
the drift is the difference between the displacement at diaphragm center
of 5F and the average displacement of vertical elements at 4F.
P-Delta
Incremental Factor(ad): When P-Delta analysis is performed, the
incremental factor becomes 1.0 irrespective of calculation results.
Note
For a story drift used for
calculating the P-Delta Incremental Factor (ad), the Maximum Drift
of All Vertical Elements is used. (Story drift as per Story
Drift Calculation Method is not used in calculating the P-Delta
Incremental Factor (ad) since the values are different depending upon
the method used.)
Allowable Story Drift Ratio
1. Maximum Drifts of All
Vertical Elements
Maximum drifts are produced for each story.
Node:
Node numbers corresponding to the maximum story drifts at each story level
Story Drift:
Incremental lateral displacement over two consecutive story levels
Modified
Drift: Incremental factor for P-Delta effect * Deflection Amplification
Factor * Story Drift * Scale Factor / Importance Factor
Story Drift
Ratio: Modified Drift / Story height
Remark:
Acceptance of story drift ratio relative to the allowable story drift
ratio
2. Drift at the Center
of Mass
Difference in lateral displacements at the
centers of mass at top and bottom ends is produced.
Drift Factor
(Maximum / Current): Maximum story drift / Story drift at center
of mass
Refer to Maximum
Drift for the remainder.
3. Average Drift of Vertical
Elements
Average story drift at a corresponding story
is produced.
Drift Factor
(Maximum / Current): Maximum story drift / Drift at the selected
node line
Refer to Maximum
Drift for the remainder.
Note
The items 3, 4, 5 & 6 are produced by right-clicking the mouse on the
table followed by selecting specific items in 'Select Calculation Method'.
Story drifts at a user selected node and
the nodes, which are located on the vertical line passing the selected
node, are produced.
Drift Factor
(Maximum / Current): Maximum story drift / Story drift at user-selected
node
Refer to Maximum
Drift for the remainder.
5. Average Drift of Vertical
Lines on Selected Nodes
Average story drifts of building column lines
selected by the user are produced. The
column lines here should be selected at the extremities of the building
plan.
Drift Factor
(Maximum / Current): Maximum story drift / Average story drift
of the building plan extremities
Refer to Maximum
Drift for the remainder.
Context
Menu (Select Calculation Method)
Story
Drift Calculation Method dialog box
6. Shear Weighted Average
Drift of Vertical Elements
Shear forces in the vertical members are
reflected into the story drifts.
The shear weighted average drift is produced
only when the 'Story Shear Force Ratio of Member' option is applied in
Model>Building>Control
data.
Story Drift:
: member shear force at story
: horizontal displacement
of each story member
Drift Factor
(Maximum / Current): Maximum story drift / shear weighted average
story drift
Refer to Maximum
Drift for the remainder.
7. Context Menu
The user provides the data for calculating
modified story drifts and P-Delta incremental factors. These
are required values for generating the table. When
Table is invoked, the set Story Drift Parameters window is executed first.
Context
Menu (Set Story Drift Parameters)
Set
Story Drift Parameters dialog box
Modify
Beta dialog box
Response Modification
Coefficient
Deflection Amplification
Factor
Importance Factor
Scale Factor:
Cm, Scale-up Factor
Vertical
Load Combination: Define a vertical load condition to consider
the P-Delta effect.
Note
All the items other than Response Modification Coefficient are applied
only for IBC 2000 and KBC 2005.