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Shearwalls requires that all structure blocks have the same height for each level and that all walls on one level have the same height. This means that the diaphragm is at the same height throughout the structure and that split-level conditions are not possible. There is no specific guidance in codes and standards on how to analyze split-level conditions. If you want to provide general design procedures for this condition, please contact WoodWorks Technical support. If you want to account for the strength and stiffness of different wall heights it is recommended to make a model of the structure based on the lowest or tallest wall height, and then create separate single wall project files as shown in tutorial 1 ( CDN, U.S.) for the walls that have a different height.

Features which allowed for this capability have been removed from shearwalls until a new feature which would allow the input of proprietary shear resisting elements can be incorporated into the program.

Currently, it is not possible to model or design skewed walls with the Shearwalls program. There is an existing feature request to include skewed walls in the program.

This sort of condition can occur in lofts or in the foyer of a 2 storey structure. Shearwalls assumes that the structure will consist of platform frame construction and the diaphragm is continuous throughout the storey. To handle these situations, it is recommended to create two project files. For example, in the case of a 2 storey structure, with an open foyer that has a 2 storey wall at the front of the structure, one project file would consist of a 2 storey building that could be used to design all the single storey walls in the structure. In the locations where the 2 storey walls occurs, you could specify 1 storey shearwalls for the purpose of attracting loads. Then using the loads from the first project file, a single wall project file could be created as shown in tutorial 1 ( CDN, U.S.) for the walls that span 2 storeys. The results from both project files could be compared to determine the appropriate design.

Roof blocks have two purposes in the software. They are used to create roof weight(s) that contribute to the total weight of the structure which is used to generate the seismic loads, and based on their shapes, roof blocks are also used to generate lateral wind loads for the purpose of designing the main wind lateral force resisting system. Shearwalls does not automatically generate wind uplift loads. Taking time to draw complex roofs with many hips and valleys that would require 8 or more roof blocks is time consuming and may not be necessary for structural analysis. Instead, the complex roof could be simplified to fewer roof blocks which generically model the shape of the roof. For an example an discussion of a complex roof where this would be applicable.

In WoodWorks^® Shearwalls, when you click the “Generate Loads on selected levels” button on the “Generate Loads” form, a log file detailing the load calculations is created. The log file will automatically become available at the top of the Shearwalls menu. The log file is also automatically saved under the same name of the project file (with extension .log) in the same folder. Before the analysis is run, the log file includes information on how both the wind and seismic loads were generated. A summary of the site specific wind and seismic parameters, list of equations and resulting calculations are provided. If seismic loads have been generated, once the analysis of the model is run, the log file will update to include the torsional analysis results for the seismic loads.

The seismic redundancy factor takes into account structural redundancy in the lateral force resisting system, and is used to modify any forces induced by horizontal earthquake loads as described in Section 12.3.4 of the ASCE 7-10. In general, this factor applies to buildings that are much longer than they are wide, or have very short shear resisting elements along the shearlines. The input for rho in the East-West and North-South building directions is located in the Site information view, with the choices of selecting calculated, 1.0 or 1.3. Users have the option of allowing shearwalls to calculate the redundancy factors or they can circumvent the calculation and select 1.0 (Seismic Design Categories A, B, and C – 12.3.4.1) or 1.3 (Seismic Design Categories D, E and F – 12.3.4.2), based on their own calculations. Note that the program does not consider overstrength factors, as these are not required for light frame construction (ie. Clause 12.3.4.1.5 is not checked by the software). See the help files for further details on how the software calculates the seismic redundancy factor.

Structure blocks are used to quickly establish the exterior perimeter of the structure. Multiple structure blocks are meant to be utilized when there are portions of a structure which vary in height (ie. Two storey house attached to a one storey garage). It is not necessary to draw the structure blocks to match the roof shape as it is possible to draw as many roof blocks as desired once in roof block view.
Using multiple structure blocks is not necessary and can over complicate a model. It may be possible to achieve the correct shape of the structure once in walls view by splitting and shifting exterior walls. Split walls by tracing another wall on top of an existing one, then move the wall by clicking on the segment, then holding the shift key to move the wall segment.
The method for splitting and moving walls is shown in US Shearwalls tutorial 2  and in CDN Shearwalls tutorial 2. Tutorial 11 in the user guide provides further discussion and demonstration of when and how to utilize structure blocks.

Click Settings/Design, under local building code capacity modification, it is possible to adjust the plywood sheathing shear strengths. The default values are 1.0, but can be modified to conform to local conditions. For example, Los Angeles Building Code mandates or at one time mandated a 75% reduction in shear capacities for seismic design. If the factor is still in effect, users should save or enter “0.75”as their default local building code modification factor for seismic loads. Similarly, there are counties in the Southeast USA that require a reduction in shear strength for high wind loads. Users in these areas should check their local building codes and apply the factor if the locally mandated shear strength differ from those published in the IBC or SDPWS.

WoodWorks® Shearwalls allows users to specify the maximum plan or elevation offset for walls to be considered on the same shearline. These settings are found under Maximum Shearline Offset in the Settings, Design tab. The maximum plan offset is dependent on the specified plan offset and elevation joist depth. By default, Maximum Plan Offset in the plan is set as 0.5 ft (0.15m) and the Elevation offset is set as 1 joist depth, to account for errors while drawing walls. The above values are recommended to provide tolerance for the automatic shearline generation routine. However, the software allows the user to change the default values at their discretion For example, the CWC Engineering Guide for Wood Frame Construction, which provides guidance on the design of light-frame wood structures which meet the requirements of a Part 9 prescriptively design structures, allows for a maximum shearwall plan offset of 4 joist depths, up to a maximum of 1.2 m ( 2014 Engineering Guide for Wood Frame Construction Part B Figure 10.1.5). Similarly, in the US, the Wood Frame Construction Manual allows shearwall plan offsets up to 4 feet ( WFCM 2015 Clause 2.1.3.3.c.). The maximum shearline offset feature can be utilized to match similar requirements when modelling a structure.

This is a known issue with the Shearwalls program. When printing the design results, Shearwalls reduces the number of pages compared to the number of pages listed and displayed in the Results view. To avoid the issue, it is recommend to print the Results to a pdf, then print the desired pages.