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Frequently
Asked Questions
What does
LatPro IBC do?
- LatPro IBC allows
the user to enter site information, building dimension and weight
inputs to simultaneously calculate wind and seismic loading for
light framed structures up to three stories.
The majority of the
building information is entered on a diaphragm by diaphragm basis.
The diaphragm loads are then assigned to gridlines by allocating
a portion of the diaphragm forces to specific gridlines. This
is done with a tributary width allocation and is assigned to a
gridline with easy to use, pull-down menus.
Once all of the diaphragm
forces have been assigned to gridlines, the user can easily specify
the shear walls, shear wall chord (edge) members, holdown connectors
and posts that are required to resist the gridline shear forces.
When defining the shear wall chord members, connectors, and posts
supporting shear walls above, the program has inputs for live
and dead loads in order to size the member based on the code defined
allowable stress design load combinations.
LatPro IBC also allows
the user to easily calculate component and cladding design pressures
by entering the effective area and selecting from the appropriate
type, zone and location for wall and roof members.
What analysis methods
does LatPro IBC use?
- LatPro IBC utilizes
the Equivalent Lateral Force method for seismic analysis and the
Analytical Method for All Heights for wind analysis.
Do I have to redraw the
structure in LatPro to analyze it?
- No, however, when
laying out gridlines to define diaphragm boundaries and shear
wall lines, the LatPro produces a graphical representation. This
is to visually help the user with data entry and avoid mistakes.
Can I run LatPro without
Excel?
- No, LatPro requires
Excel. All data entry is done in simple-to-understand graphical
windows. Excel runs in the background and is not apparent to the
user.
How
does LatPro model stacked shear walls?
- LatPro allows
the user to model stacked shear walls in order to transfer the
uplift and compression forces to the shear wall below by "linking"
it to a shear wall above.
How
do I enter data into LatPro? Do I have redraw the structure in LatPro
to analyze it?
- No, LatPro
does not require the user to redraw the structure to model it.
LatPro allows the designer to work directly off a set of prints
to layout diaphragms, grids, shear walls, posts, connectors, and
transfer shear wall uplift and compression forces to the foundation.
This method simplifies the analysis, reduces errors, and does
not require a complicated, time-consuming modeling process.
- By working
directly on a set of prints for the project, the engineer can
review any unusual conditions including out-of-plane or in-plane
offsets, unusual dead load tributary loading, unusual wall heights,
support below shear walls, etc. This method reduces errors inherent
in creating another drawing to create a model for lateral analysis,
which may not include unusual or critical information that is
shown on the design drawings.
Is
LatPro IBC compliant?
- Yes, LatPro IBC 2009
is 2009 IBC compliant and is also 2010 California
Building Code (CBC) Compliant.
What if I want
to use a different type of shear wall that is not in the default
shear wall schedule?
- There is a User-Defined
menu that allows the user to add site-built and pre-built shear
walls to the existing default schedule. These walls can be entered
right away or anytime while sizing a shear wall within a project.
Connectors and holdowns may also be added to the existing database
within the same User-Defined menu.
How do I model a shear
wall that straddles two diaphragms?
- LatPro IBC allows
the user to assign the forces from multiple diaphragms to a gridline.
The shear walls are then designed to resist the resulting gridline
force. For shear walls that straddle two diaphragms, tributary
area above the shear wall can be defined with different live and
dead loads for the two different diaphragms. The live and dead
load inputs are used with the ASD load combinations to size the
shear wall chord/edge member and the holdown connector.
Why do some of
the items in the story components window display items in red?
- This is to alert the
user that the entry is insufficient and needs to be corrected;
either the shear demand on the wall is greater than the capacity
or the deflection is too large for seismic drift limits. Any items
in red will also show up in the error check as an error.
After entering
all the building information and building design data, why are the
acting wind and acting shear wall values shown on the shear wall
tab as zero on some of the grid lines?
- On the Tributary Width
input window, if the check box for "Transfer directly into
concrete foundation wall" is checked, that specific tributary
width allocation force will not be include in the gridline force
to be resisted by shear walls. So, if this box is checked for
all allocations, the shear walls will have zero acting wind and
seismic force to resist.
The purpose of the
check box is to allow the user to model situations where floor
or roof diaphragms attach directly to a concrete foundation/retaining
walls, without a wood cripple wall in between. In these situations
the user is able to transfer the diaphragm forces directly into
the concrete foundation without having to resist the forces with
specified shear walls.
What does "Projected
Roof Area" mean in the define diaphragm input window?
- The projected roof
area is area that is seen on an elevation drawing. It is the same
as the total roof area (oriented towards the specified N, S, E,
or W direction) multiplied by the Sine of the roof slope.
What do I enter
for projected roof area in the define diaphragm input window if
a diaphragm ends on an interior wall?
- In this situation
the diaphragm edge that ends on an interior wall may have zero
projected roof area and zero exterior wall length inputs.
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