ETABS – 12 Occupancy Loads using Shell Uniform Load Sets: Watch & Learn

ETABS – 12 Occupancy Loads using Shell Uniform Load Sets: Watch & Learn


This tutorial will show how to define and apply floor loads based on occupancy using the shell uniform load sets command shell uniform load sets allow multiple
types of loads such as dead and live to be
assigned in a single operation this means that
you can create occupancy specific load assignments for
example you could create one load set for office
space in a building and another load set for warehouse or
storage space for this example we will assume that we
are developing two load sets for a multi-story
residential building one to represent the load within the
residences and one for the load on the corridors we will isolate a single story so that
it will be easier to explain how we define and assign the shell uniform load sets we start with just the beam and column
framing onto which we will add the floor slab in this case we will draw a total up three floor objects the first floor object represents a
corridor the next two floor objects represent residential space so that we can see the different area
objects better we will highlight the corridor as previously stated we will define one load set for the
residences and one for the corridor these load sets
will contain three types of loads dead superimposed dead and live reviewing the load patterns we see that
the three patterns have been defined the dead load pattern with a self
weight multiplier of one the live load pattern and a superimposed dead load pattern that will be used for miscellaneous
loads like mechanical and plumbing now we define the shell
uniform load sets clicking the Add button we will name our first load set residential the first load pattern we
will add will be dead and it will consist of only the
self-weight so no additional load will be defined
the next load pattern used will be the superimposed dead and for the residential space we will
use 10 pounds per square foot the last
pattern in the set will be live and we will set the load
to 40 pounds per square foot the next load set added will be for
the corridor again the dead pattern will be added
with only the self-weight the superimposed dead pattern will have a load of 30 pounds per
square foot and the live load will use a load of 100 pounds per square foot we next select the slab objects that
support the residences and go to the Assign shell loads uniform load sets command here we select residential and click the Apply button note that residential is now displayed on the
plan with the form still open select the interior floor object which
is the corridor and highlight corridor and then click apply all of the floor loads have now been
applied now lets verify the loads first we display the dead load no
additional loads are shown since this pattern is for self-weight only the superimposed dead load shows 30 pounds per square foot along
the corridor and 10 for the residences and the live load shows 100 in the corridor and 40 in the
residences all of which are as expected a right click
on the different floor objects confirms that the appropriate load sets have been assigned now we will run the analysis switching to a 3d view and displaying
the moment in the slab we can step through the results for each
of the three load cases dead sdead and live note that the moments appear
symmetrical for the dead case but unsymmetrical for both the sdead and live cases as expected due to the
different loading along the corridor thus we were able to
apply three different load patterns a dead
load a superimposed dead load and a live load to each floor object with
a single assignment of a load set now we will see how easy it is to alter
the applied floor loads we will unlock the model and return to the
define shell uniform load sets command let’s say that for some reason we wish to add a
load value of 20 pounds per square foot to the dead pattern for the residences if we return to the display of loads we see that the dead load pattern now
shows a 20 pounds per square foot load at each of the residences thus once the load sets have been assigned it
is a trivial process to revise the applied loads to the floors by simply altering the
load set we can change the load on every floor
object to which it is assigned this is obviously a very powerful
capability when dealing with multi-story buildings or buildings with complex floor loading
layouts where reselecting floor objects and
reassigning the loads can be a time-consuming task this
concludes this tutorial on defining and assigning
shell uniform load sets

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