ETABS – 09 Shear Wall Design and Optimization: Watch & Learn

This tutorial will discuss the types of
shear wall design available in ETABS as well as
describe the capability that exists to optimize shear walls for drift we will start by illustrating the three
types of shear wall design in ETABS first is
the simplified compression and tension design which designs planar
walls next is the uniform reinforcing approach which can design or check 3d walls using uniform reinforcing patterns this is the default design and last is
the general reinforcing option which can design or check 3d walls
using arbitrary reinforcing patterns defined in the section designer program the shear wall we will design is one
story tall and 10 inches thick however before a wall
can be designed it must be assigned a pier label select the wall and go to the Assign shell pier label command and assign a label in this case p1 we can now run the analysis with the analysis complete we are ready
to start the design select the wall and go to the design
shear wall design command next go to the Assign pier sections
command and here’s where we select which of the
three types of wall designs to assign we will start with the simplified
compression and tension approach with the wall still selected go back to the design menu and select
the View revise overwrites command here we verify our design parameters note that T and C is selected and that
the wall is 10 inches thick and if we wanted to we could define edge
members using the DB dimensions for both the left and right sides at the
bottom and top we are now ready to start the
design the required longitudinal reinforcing is displayed on the wall a right-click brings up a detailed design sheet
showing flexural shear and boundary check information select the wall once more and again go back to the assign
pier sections command but this time select the uniform
reinforcing option in the form you can specify the
distributed uniform reinforcing and the end bars as well as whether the
wall should be checked or designed we will select the checked
option if we select the wall and go back to the view revise pier
overwrites command this time the form displays uniform
reinforcing as the type the reinforcing we selected and that it is a check next we re-run the design check command and the total longitudinal reinforcing
specified is shown a right click brings up detailed
information on the check including the demand capacity ratios if we wanted to display the DC ratios on
the model we can do so using the display design info command next we will use the general reinforcing option however prior to
assigning this type we must define the section using section
designer this is done through the define general
pier sections command we will add a new pier section but we will base it on the existing p1 wall pier geometry click on the
section designer button to edit or modify the section including
right clicking on the reinforcing to bring up a form where we can change the
size and spacing as needed when the changes are complete click on
the OK button now we can assign the section designer
section to the wall by selecting the wall and going to the assign pier
sections command and choosing the general reinforcing
option highlight the section we defined for both
the bottom and top and make sure that the check option
is selected if we go back to the view pier
overwrites command note how the form has changed to reflect
our current design choices once again start the check of the wall
the total longitudinal steel is shown a right click displays the
design form including the demand capacity ratios as a last step select the wall and change from check to design for the general reinforcing
choice start the design again and now that the program is doing design
rather than checking it displays the required longitudinal reinforcing rather than the
reinforcing that was specified in the section
designer one other powerful feature that ETABS offers when
designing shear walls is the ability to select the thinnest
wall section that satisfies lateral drift
requirements the section is picked from an auto
select sections list that the user creates similar to what is
done in steel and concrete frame design we
start by going to the define section properties wall sections command here we have previously defined 7 wall
sections ranging in thickness from six inches
thick to 18 inches thick clicking the Add new property button we will name this property auto select and choose a property type of auto select list when this property type
is selected the Modify show auto select list button
becomes active clicking on this button we will add our seven wall sections to the auto
select list note that our starting section is the median property which in this
case is wall 4 which is 12 inches thick next we select
the wall and assign the auto select property
just defined note that wall 4 the median section is
shown on the display next we will set the lateral drift
target by going to the design set lateral displacement targets command here we set the maximum displacement at
the top of the wall to 1 inch for our lateral load case we are now ready to run the analysis and once the analysis is complete we can
move on to design a check of our pier overwrites shows that design using uniform
reinforcing has been selected which is the default and typically what
should be used with auto select lists we can now click the Start design
command and after it is finished a right-click shows that the median
section the 12 inch thick wall has been used for the first cycle of analysis and design a check of the
displacement shows an X translation of 0.57 inches significantly below our
target of 1 inch and therefore a thinner
section can be used the section thickness will not be
adjusted until we rerun the analysis after running the second analysis the
wall section has been updated it now uses wall 2 as shown in the
display wall 2 is our second thinnest section
eight inches thick we will now rerun the design and the required longitudinal steel for
section wall 2 is displayed a check of the displacement shows that the X translation has
increased to 0.86 inches using the thinner section this is
still below our maximum of one-inch and thus is an acceptable section this
concludes this watch and learn on shear wall design.

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