What Structural Engineers Need to Know About the New OSHA Silica Dust Standards

This week’s post was written by Todd Hamilton, PE. ICI Field Engineer at Simpson Strong-Tie.

In March of 2016, the United States Department of Labor issued new OSHA standards on how crystalline silica dust should be handled in various workplaces including within the construction industry. The changes are intended to limit workers’ exposure to and inhalation of silica dust on the jobsite. These regulations will replace the current standard, which was issued in 1971. Compliance with the new rules will be required on construction jobsites starting September 23, 2017, and will be enforced through OSHA from that time forward.
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Q&A About Advanced FRP Strengthening Design Principles

Our thoughts go out to everyone affected by Hurricane Harvey and this disaster in Texas. To help with relief efforts we are donating $50,000 to the American Red Cross Disaster Relief Fund. Employees at our Houston warehouse are safe and the employees from our McKinney branch will be doing as much as they can to help with relief efforts.


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Meet the First Simpson Strong-Tie Engineering Excellence Fellow with Build Change

Introducing James P. Mwangi, Ph.D., P.E., S.E. – our first annual Simpson Strong-Tie Engineering Excellence Fellow with Build Change. James Mwangi will write a quarterly blog about his experience throughout the Fellowship.

I’m delighted to have been asked to contribute this post and feel honored to be the first-ever Simpson Strong-Tie Engineering Excellence Fellow with Build Change. It’s my hope that this post will inform you about my professional background, why I applied to the Fellowship and how I think the Fellowship can benefit people and the structures they live, work and go to school in.
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Revisiting Stainless-Steel Nail Calculations . . . .

This week’s post was written by Bob Leichti, Manager of Engineering for Fastening Systems.

Those of you who have been following the Simpson Strong-Tie SE Blog for a while may recall our 2013 blog post on the withdrawal resistance of stainless-steel nails. There have been several developments relating to that subject since that blog was posted, and we want to help you catch up.

First, the National Design Specification for Wood Construction (NDS) was revised in 2015. In the 2015-NDS revision, a new chapter 10, Cross-Laminated Timber, was created, moving Dowel-Type Fasteners from Chapter 11 to Chapter 12. Every place in the original blog post where there is a snip of the NDS, you will find the same information in NDS-2015 Chapter 12. Did you know that you can download a free, view-only copy of the NDS from the American Wood Council at awc.org?

Second, after we published our blog post about stainless-steel nail withdrawal, a journal paper was published about withdrawal resistance of stainless-steel nails. This paper has all the nitty-gritty related to withdrawal resistance and bending yield strength for smooth-shank stainless-steel nails: Ramer, D.R. and Zelinka, S.L. (2015). “Withdrawal Strength and Bending Yield Strength of Stainless Steel Nails,” Journal of Structural Engineering, American Society of Civil Engineers, Vol. 141, no. 5, 7 pp. (DOI: 10:1061/ASCE)ST.1943-541X.0001088).

Third, the NDS has been through another revision cycle and will soon have a 2018 copyright date. The chapter on dowel-type fasteners has some significant revisions that we will discuss in a blog post when the NDS-2018 is published later this year. SPOILER ALERT: NDS-2018 has a new withdrawal function for smooth-shank stainless steel nails.

Stay tuned!

The Cold-Formed Steel Construction Catalog is HOT off the press!

The SE Blog is taking some time off for the 4th of July holiday this week. However, we’ve just released the 2017 edition of our Connectors for Cold-Formed Steel Construction catalog – order a hard copy to be mailed to your office or download a PDF copy and start using it today!

Connectors For Cold-Formed Steel Construction

The C-CF-2017 is a 308-page catalog including specifications, load tables and installation illustrations for our cold-formed steel connectors and clips, helping you easily specify and install in commercial curtain-wall, mid-rise and residential construction.


How Heat Treating Helps Concrete Anchoring Products Meet Tougher Load Demands

Joel Houck is a senior R&D engineer for Simpson Strong-Tie’s Infrastructure-Commercial-Industrial (ICI) group based out of the new West Chicago, IL location. He has spent the last 17 years with Simpson developing new mechanical anchors and adhesive anchor components, as well as developing a lot of the lab equipment required to test these products. This experience has given him extensive knowledge and insight into the concrete anchor industry, especially when it comes to the proper function and performance of anchors. Joel is a professionally licensed mechanical engineer in the state of Illinois.

There’s a saying in Chicago, “If you don’t like the weather, just wait fifteen minutes.” That’s especially true in the spring, when temperatures can easily vary by over 50° from one day to the next. As the temperature plunges into the blustery 30s one evening following a sunny high in the 80s, I throw my jacket on over my T-shirt, and I’m reminded that large swings in temperature tend to bring about changes in behavior as well. This isn’t true just with people, but with many materials as well, and it brings to mind a thermal process called heat treating. This is a process that is used on some concrete anchoring products in order to make them stronger and more durable. You may have heard of this process without fully understanding what it is or why it’s useful. In this post, I will try to scratch the surface of the topic with a very basic overview of how heat treating is used to improve the performance of concrete anchors.

According to the ASM Handbook: Heat Treating, heat treatment is a process of heating and cooling a solid metal or alloy in such a way as to obtain desired conditions or properties.1 In practical terms, metals (usually steel in the case of most concrete anchors) are heat treated in order to improve their properties in some way over their base condition. When steel wire is formed into the complex shapes of anchors during the manufacturing process, the steel needs to be soft and formable; however, it is often beneficial to the performance of the final anchor product to be much harder and stronger than the base steel from which it’s formed. That’s where heat treating comes into play. By heating and cooling soft steel in a controlled manner, changes are made to the crystal structure of the steel in order to improve mechanical properties such as hardness, toughness, strength or wear resistance. Although the steel undergoes very complex microstructural changes during the heat treatment process, the end result is fairly straightforward – the once soft steel becomes harder and stronger as dictated by the heat treating process. As concrete anchors become more and more complex in order to meet the needs of building codes and designers, heat treating is becoming a more common and necessary component of high-strength anchors.

Figure 1. Steel microstructures: (a) soft steel example; (b) heat treated steel example.2

Depending on the desired results, there are many different types of heat treating processes that can be considered. The type of heat treatment and the parameters that are used can be customized for the steel type and the specific anchor application. There are several different types of heat treatments that are typically used for anchors. Two of the most common types are through hardening (also called neutral hardening) and surface hardening (also called case hardening).

Figure 2. Fasteners entering a heat treating furnace.3

Through hardening changes the mechanical properties (hardness, strength, ductility, etc.) of the steel without affecting its chemical composition. In order to alter the microstructure of the steel, it is heated in a furnace to a very high temperature, and then rapidly cooled, usually by submerging it in a liquid quench medium such as water or oil. This process will generally result in a very hard, but brittle material, so a secondary operation, called tempering, is employed after quenching. To temper steel, it is reheated to a lower temperature and then cooled in order to remove the stresses and brittleness created during the original quenching operation. Through hardening is useful where increased strength and toughness are required and surface wear isn’t a big concern, such as in our Crimp Drive® and split-drive anchors, setting tools for drop-in type anchors, high-strength all-thread-rod for adhesive anchors, and gas- or powder actuated fasteners. In order to effectively through harden an anchor, moderate levels of hardening elements must be present in the base steel, usually in the form of carbon. As the carbon content in the steel increases, so does the ability to harden it. The chemical composition of the steel along with the specific heat treating parameters will determine the level of hardness, strength and toughness of the final parts.

Surface hardening changes the hardness of the steel at the surface of the part by modifying the chemical composition of the steel at its surface only. This is done by altering the atmosphere in the heat treating furnace in order to get alloying elements, usually carbon, to diffuse into the surface of the steel. The increased carbon content increases the hardenability of the steel at the surface, but it can’t penetrate deeply into the steel, so a thin case forms around the surface of the steel with higher strength and hardness than the interior of the part. This creates parts that have high ductility throughout most of the interior, but that also have hard, wear-resistant surfaces. This type of heat treatment is useful in heavy-duty anchors where components of the anchors are sliding against each other during the setting process. It’s also useful in screw anchors, where the steel threads need to be very hard and wear resistant in order to cut into the concrete, but the ductility of the anchor must be maintained in order to avoid brittle failures in service. Just as with through hardening, there are many variations of surface hardening used in anchors, depending on the specific application.

Figure 3. Cross-section of surface hardened bar showing different hardness zones at the surface and in the interior.4

By using these two processes along with other heat treating processes, we are able to expand our ability to meet the higher demands placed on anchors in an industry that continues to evolve. As heat treating and steel chemistry continue to innovate, we will continue to use these developments to provide our customers with No-Equal concrete anchors that meet our high standard for performance and safety.

Mechanical Anchors

From complex infrastructure projects to do-it-yourself ventures, Simpson Strong-Tie offers a wide variety of anchoring products to meet virtually any need.


 

1 Lampman et al. (1997). ASM Handbook: Heat Treating. Materials Park, OH: ASM International.

2 “Microstructure of the AISI 4340 Steel.” Digital Image. Research Gate, n.d. Web. 14 June 2017 https://www.researchgate.net.

3 “Heat Treat Furnace.” Digital Image. ThomasNet Web Solutions, n.d. 14 June 2017 http://www.morganohare.com/heat-treating.html.

4 “Macrographs Showing Case Depth of Steels.” Digital Image. Science and Education Publishing Co. Ltd, n.d. 14 June 2017 http://pubs.sciepub.com.

Introduction to the Site-Built Shearwall Designer Web Application

Written by Brandon Chi, Engineering Manager, Lateral Systems at Simpson Strong-Tie.

Wood shearwalls are typically used as a lateral-force-resisting system to counter the effects of lateral loads. Wood shearwalls need to be designed for shear forces (using sheathing and nailing), overturning (using holdowns), sliding (using anchorage to concrete) and drift, to list some of the main dangers.  The Simpson Site-Built Shearwall Designer (SBSD) web app is a quick and easy tool to design a wood shearwall based on demand load, wall geometry and design parameters.

The web application provides two options for generating an engineered shearwall solution: (1) Solid Walls; and (2) Walls with Opening using the force-transfer-around opening (FTAO) method. Both options generate solutions that offer different combinations of sheathing, nailing, holdowns, end studs and number/type of shear anchors. The app can generate a PDF output for each of the possible solutions. Design files can be saved and reused for future projects.

App Overview

Design Input: 

Figure 1 shows the input screens for the “Solid Walls” and “Walls with Opening” designs with common wall parameters that are applicable to both design options. The user interface uses quick drop-down menu and input fields for the designer to select the different options and parameters. Unless otherwise noted, all the input loads are to be nominal (un-factored) design loads. The application will apply load combinations to determine the maximum demand forces for the shearwall design.

Figure 1A. Application Design Criteria Input. – Solid Wall
Figure 1B. Application Design Criteria Input. – Walls with Opening
Figure 1C. Application Design Criteria Input. – Common Wall Input Parameters

Figure 2 shows the allowable stress design (ASD) load combinations used for calculating the demand loads for the different components of the wood shearwall (i.e., holdown, compression post, sheathing and nailing design, etc.).

Figure 2. Load Combinations.

In addition to the lateral loads (wind and seismic) applied at the top of the wall and the wall’s own weight, uniform loads on top of the wall and concentrated point loads at the end posts can also be modeled. (See Figure 3.)

Figure 3. Addition Loads on the Wall.

Embedded anchor or embedded strap holdowns can be modeled by the app. (See Figure 4.) For the embedded strap option, additional input parameters are required since they will affect the allowable load of the selected strap holdown.

Figure 4. Holdown Design Options.

The Designer has the option to include additional sources of vertical displacement for drift calculation. (See Figure 5.)

Figure 5. Other Sources of Vertical Displacement Options.

Design Calculations:

For hand-calculated design when the demand forces are determined, the holdown size and shear anchorage can be selected from tabulated values. Design for the sheathing/nailing and compression post is relatively straightforward as well; however, the shearwall drift calculation may take a bit more work. This is where the SBSD app comes in handy. Below are two sections on the shearwall drift and strap force calculations and assumptions used in the SBSD application. If you are interested, please contact Simpson Strong-Tie for other design assumptions used in designing the SBSD app.

Shearwall Deflection Calculations:

Equation 1 shows the shearwall deflection equation from the 2008 Edition of Wind & Seismic Special Design Provisions for Wind and Seismic (SDPWS).

The Δa value from the third term of the equation is the total vertical elongation of the wall holdown system from the applied shear in the shearwall. The third term accounts for the additional displacement from holdown displacement. For holdown deflection, the deflection value depends on the post size used with the holdown size. When hand-calculating shearwall drift, Designers may have to perform a couple of iterations to come to the final post and holdown size. The SBSD app accounts for the holdown displacement and the post size used for overturning force calculation.

For shearwall-with-opening deflection calculation, EQ-2 is used in the SBSD app.

The solid wall, ∆solid wall, term is calculated using EQ-1 above. For the window strip and wall pier deflection terms, the height “h” used in EQ-1 is taken as the height of the window opening. ∆a is the deflection from nail slip in the shearwall. For more information regarding shearwall deflection with opening, please refer to Example 1 in Volume 2 of the 2015 IBC SEAOC Structural/Seismic Design Manual.

Strap Force Calculations:

For the Wall with Opening design option, there are several methods (Drag Strut, Cantilever Beam, SEAOC/Tompson, Diekmann) to calculate the force transfer around the opening. In the SBSD app, the Diekmann technique is used to calculate the pier forces in the shearwall and the strap forces around the opening. When calculating the strap forces, the SBSD app assumes they are the same at the top and bottom of the opening. In addition, contribution of the gravity load only affects the overturning forces in the holdown and post design but not the wall pier forces or strap forces.

Design Output:

Once all design parameters are entered and calculated, a list of possible solutions (where available) will be shown. (See Figure 6.) Common parameters such as sheathing material and type, wood species, minimum lumber grade, etc., are shown first, followed by other design parameters. The user can filter the solutions by seismic drift or wind drift.

Figure 6. Onscreen Output.

The Designer can select the PDF button next to the desired solution to see a PDF design file on a separate screen. (See Figure 7.)  The PDF design file contains the detailed design criteria input by the Designer, calculated demand loads, shearwall material summary, and a design summary for holdown, sheathing, and compression post design. A detail summary for shearwall deflection is also shown, with each term of the shearwall deflection equation (EQ-1) separated. Shear anchorage and design assumption notes follow the design summary section. This PDF file can be saved and printed by the Designer.

Figure 7. Detailed PDF Output.

I hope you find the SBSD web app helpful for your day-to-day wood shearwall design needs. If you have any questions or comments, please leave them in the comments section below.

What Makes a Good Training Facility?

When it comes to choosing a training facility, there are many well-researched principles about what makes an environment conducive to improved adult learning.

While we try to hold all training events in facilities that meet most of these principles, (even when traveling to our customers or users means we have to conduct events in hotel meeting rooms) we prefer to host you at our own locations.

To this end, we invest a tremendous amount of time and resources to build and offer dedicated training facilities across the country. These facilities meet all the basic requirements for improved adult learning, but much more as well.

By having our own dedicated training facilities, we can provide learners with a much richer experience and contextually relevant displays.

These displays include partially deconstructed wall segments, foundations and roof systems that give learners a bigger picture of the applications being studied.

Many displays allow for hands-on installations and exercises that allow for improved comprehension of the product use and limitations. Even for the engineering community, who typically are limited to images from a catalog, the hands-on activities add great value. It’s always interesting to see the reaction that engineers have to actually seeing a system approach and having an opportunity to participate in learning that goes way beyond sitting and listening to a lecture.

Sometimes learners just need to see, feel or hold something in order to really understand a concept or product application. We make every effort to bring legitimate educational content to our workshops, supported by products that we hope will furnish solutions to your needs.

Many of our facilities include a plant tour and/or testing-facility tour as well. While these components don’t always align directly with the learning objectives, they do offer a chance for our guests to raise their energy levels and get a better understanding of that scale, capabilities, and commitment to quality that we bring to bear in our endeavor to help people build safer structures.

Additionally, we offer our facilities to customers, associations and industry organizations to use for their own meetings and training events. If you haven’t been to one of our workshops or visited one of our facilities, I highly encourage you to join the 35,000 plus who have over the last four years. You can find a complete list of workshops on our training home page. I expect that you’ll find it an educational and highly engaging experience that helps you build safer structures as well.

This blog post was written by Charlie Roesset, Director of Training for Simpson Strong-Tie.

Decrypting Cold-Formed Steel Connection Design

As published in STRUCTURE magazine, September 2016. Written by Randy Daudet, P.E., S.E., Product Manager at Simpson Strong-Tie.  Re-posted with permission. 

One of the world’s greatest unsolved mysteries of our time lies in a courtyard outside of the Central Intelligence Agency (CIA) headquarters in Langley, Virginia. It’s a sculpture called Kryptos, and although it’s been partially solved, it contains an inscription that has puzzled the most renowned cryptanalysts since being erected in 1990. Meanwhile, in another part of the DC Beltway about 15 miles to the southeast, another great mystery is being deciphered at the American and Iron Institute (AISI) headquarters. The mystery, structural behavior of cold-formed steel (CFS) clip angles, has puzzled engineers since the great George Winter helped AISI publish its first Specification in 1946. In particular, engineers have struggled with how thin-plate buckling behavior influences CFS clip angle strength under shear and compression loads. Additionally, there has been considerable debate within the AISI Specification Committee concerning anchor pull-over strength of CFS clip angles subject to tension.

cfs-clip-attachment

The primary problem has been the lack of test data to explain clip angle structural behavior. Even with modern Finite Element Analysis (FEA) tools, without test data to help establish initial deformations and boundary conditions, FEA models have proven inaccurate. Fortunately, joint funding provided by AISI, the Steel Framing Industry Association (SFIA), and the Steel Stud Manufactures Association (SSMA) has provided the much-needed testing that has culminated in AISI Research Report RP15-2, Load Bearing Clip Angle Design, that summarizes phase one of a multi-year research study. The report summarizes the structural behavior and preliminary design provisions for CFS load bearing clip angles and is based on testing that was carried out in 2014 and 2015 under the direction of Cheng Yu, Ph.D. at the University of North Texas. Yu’s team performed 33 tests for shear, 36 tests for compression, and 38 tests for pull-over due to tension. Clip angles ranged in thickness from 33 mils (20 ga.) to 97 mils (12 ga.), with leg dimensions that are common to the CFS framing industry. All of the test set-ups were designed so that clip angle failure would preclude fastener failure.

For shear, it was found that clips with smaller aspect ratios (L/B < 0.8) failed due to local buckling, while clips with larger aspect ratios failed due to lateral-torsional buckling. Shear test results were compared to the AISC Design Manual for coped beam flanges, but no correlation was found. Instead, a solution based on the Direct Strength Method (DSM) was employed that utilized FEA to develop a buckling coefficient for the standard critical elastic plate-buckling equation. Simplified methods were also developed to limit shear deformations to 1/8 inch. For compression, it was found that flexural buckling was the primary failure mode. Test results were compared to the gusset plate design provisions of AISI S214, North American Standard for Cold-Formed Steel Framing – Truss Design, and the axial compression member design provisions and web crippling design provisions of AISI S100, North American Specification for the Design of Cold-Formed Steel Structural Members, but no good agreement was found. Therefore, an alternate solution was developed that utilized column theory in conjunction with a Whitmore Section approach that yielded good agreement with test results. It was further found that using a buckling coefficient of 0.9 in the critical elastic buckling stress equation will produce conservative results. Finally, for pull-over due to tension, it was found that clip angle specimens exhibited significant deformation before pulling over the fastener heads (essentially the clip turns into a strap before pull-over occurs). However, regardless of this behavior, tested pull-over strength results were essentially half of AISI S100 pull-over equation E4.4.2-1.

Thanks to AISI Research Report RP15-2, there is a clearer understanding of the CFS clip angle structural behavior mysteries that have puzzled engineers for many years. However, just as the CIA’s Kryptos remains only partially solved, some aspects of clip angle behavior remain a mystery. For instance, how are the test results influenced by the fastener pattern? All of the test data to date has used a single line of symmetrically placed screws. This is something that does not occur for many practical CFS framing situations and will need additional research. Another glaring research hole is the load versus deflection behavior of clip angles under tension. As briefly mentioned above, the existing pull-over testing has demonstrated that excessive deflections can be expected before pull-over actually occurs. Obviously, most practical situations will dictate a deflection limit of something like 1/8 inch or 1/4 inch, but today we don’t have the test data to develop a solution. Fortunately, AISI in conjunction with its CFS industry partners continues to fund research on CFS clip angle behavior that will answer these questions, and possibly many more.

Use Strong-Wall® Shearwall Selector to Design Shearwalls

This blog post was written by Travis Anderson.

Strong-Wall Shearwall Selector-Homepage

In time for spring and summer 2017 construction projects, Simpson Strong-Tie has launched the newest version of the Strong-Wall Shearwall Selector for use with engineered design. The latest release is an easy-to-use Web-based application (that’s right, no software to download) that has been updated to comply with the 2015 IBC and now provides solutions for all three Strong-Wall Shearwall types: the Steel Strong-Wall® shearwall (SSW), the Strong-Wall wood shearwall (WSW) and the wood Strong-wall shearwall (SW). If you are familiar with the Strong-Wall Shearwall Selector, you can begin using the web application immediately. For those of you who would like to know more about the web app, please read on.

The Strong-Wall Shearwall Selector was created to help the Designer select the appropriate shearwall solution for a given application in accordance with the latest building code requirements. By performing a technical analysis, the web app provides actual drift and uplift values for a wind or seismic design shear load.

The Strong-Wall analysis also considers simultaneous, vertically applied load. In cases of multiple walls in a line, the program performs a rigidity analysis and determines the actual distributed shear to each wall. When walls are stacked in a two-story configuration, the program evaluates cumulative overturning effects to ensure that the wall, anchor bolt and anchorage to the foundation are not overstressed.

The web app provides two modes for generating an engineered solution: Optimized In-Plane Shear or Manual In-Plane Shear. The Optimized mode lists several possible solutions for the selected criteria in the order of cost. The Manual mode evaluates any number or combination of walls for adequacy based on the selected criteria. The Designer has the option to generate an Anchorage Solution based on foundation type. Once a solution has been selected, the web app will generate a pdf output. Files can be saved and reused for future designs.

Input Variables Within the Two Solution Modes:

Job Name: Enables the Designer to provide a specific job name for a project.

Wall Name: Enables the Designer to provide a name for each wall line in a project.

Wall Type (Manual Only): Solutions are provided for the selected Strong-Wall panel type: SSW, WSW, SW

Application: Defines the proposed application (use) of the wall. The choices are for walls in a garage front, a standard wall on concrete, on a first-story wood-floor system, in a second-floor non-stacked application, in a two-story stacked application, or in a balloon-framed application. For the Steel Strong-Wall® (SSW) and Strong-Wall wood shearwall (WSW), garage front may be chosen with or without the portal kit. Higher shear capacities are available when the portal kit is used.

Cold-Formed Steel Construction (CFS): This option appears for “Garage Front,” “Standard Wall on Concrete,” “First-Story, Raised-Floor System” and “Two-Story Stacked” applications. If the check box is enabled, the program will provide the proper Steel Strong-Wall model for use in CFS construction.

1st Story Wall on Wood Floor (SW – Wood Strong-Wall Shearwall only): This check box only appears if a Two-Story Stacked application has been selected. If enabled, the program will then assume the lower story wall, in a stacked application, is installed on a wood floor.

Strong-Wall Shearwall Selector-Input Variables

Design Criteria:

The design criteria may now be selected. Drop-down menus provide options for Applicable Building Code, load type, concrete strength, wall height, wall geometry and floor depth (if applicable). Entry fields may be used to indicate shear- and axial-loading information. The following applies once the appropriate design criteria have been input: If Optimized In-Plane Shear has been selected, the possible solutions are displayed in the Strong-Wall Panel Solutions list. If Manual In-Plane Shear has been selected, a list of available walls will be displayed in the Strong-Wall Panel Solutions list, any of which may then be selected and added to the desired Solution.

Strong-Wall Shearwall Selector-Design Criteria

Code: Wall solutions are provided in accordance with the requirements of the 2015 and 2012 International Building Code (IBC). Code reports may be found here.

Load Type: This criterion defines whether the input shear load is due to wind or seismic forces. The Designer must input the controlling load. The appropriate seismic “R” values are provided for the selected code.

Concrete Strength: Concrete strength may be selected based on specific project conditions. Default concrete strengths of 2500 psi, 3000 psi, 3500 psi, 4000 psi and 4500 psi are provided in the drop-down menu. Note that for shearwall selection purposes, concrete strengths are only applicable to Steel Strong-Wall® (SSW) and Strong-Wall wood shearwall (WSW). In some cases, lower anchorage forces may be obtained with a higher concrete strength. The concrete strength is also used for determining the anchorage tension capacity.

Wall Height: Select the nominal wall height. Actual wall heights are shown under the “H” column of the Solution(s).

Shear Load: Input the total Allowable Stress Design (ASD) design (demand) shear load along the wall line. Include all appropriate load factors on the shear load prior to input for the load combination under consideration. For Two-Story Stacked applications, input the story shear at each level and the program will evaluate the first-story walls for the total shear.

Floor-Joist Depth: This option appears only with first-story raised-floor systems and two-story

stacked applications. Floor-joist depth affects the capacity of Steel Strong-Wall panels installed on wood floors. Floor-joist depth is also considered in the cumulative overturning evaluation of two-story stacked wood or steel walls.

Header Thickness: This option appears only when “Garage Front” applications and wall heights of 7′ or 8′ with a header on top are selected. This option is used to select the proper Wood Strong-Wall panel model (thickness) based on the nominal header thickness of 4″ or 6″.

Header Type: This option only appears when “Header Thickness” of 4″ is selected. It then provides an option to select a solid or double-ply header. Values for the wood Strong-Wall panels will slightly decrease if the double-ply header option is selected. Steel Strong-Wall panels with multi-ply headers are limited to wind designs and SDC A-C.  .

Maximum Number of Wall Segments per Wall Line (Optimized mode only): Here the maximum number of available wall segments along a particular wall line is specified. The program enables the Designer to select a maximum of four wall segments per wall line (3 segments maximum for garage fronts.) For more wall segments per wall line, use the Manual mode.

Fill Each Segment (Optimized mode only): If this checkbox is disabled, then the minimum number of Strong-Wall shearwalls that can serve as solutions is provided up to the “Max # of Wall Segments” previously specified. If this checkbox is enabled, then the “Max # of Wall Segments” will always be used and filled with Strong-Wall shearwalls.

Segment Number, Maximum Width, Axial (lb.) (Optimized mode only): For each wall segment along a wall line, the maximum desired width of that segment and the axial load on that particular segment may be specified. The axial load is the total vertical upward or downward load assumed to act on the entire panel width. Include all appropriate load factors on the axial load prior to input for the load combination under consideration. A positive axial load reduces the actual uplift of the panel, while a negative axial load increases the actual uplift of the panel. The combined effect of the vertical axial load and overturning force is considered in the Steel Strong-Wall® (SSW) and Strong-Wall wood shearwall (WSW) solutions. The combined effect of the vertical axial load and overturning on the wood Strong-Wall (SW) shall be evaluated by the Designer so as not to exceed the “C4” and “T1” allowable vertical loads. Download an excerpt from our catalog for more information.

Axial Load 1st Story (Manual mode only): See discussion above on axial load. The axial load selected is initially applied on all Available Wall solutions. As walls are selected using the “Add” button, the axial load remains constant. If it is desired that each wall have a different axial load, then input the corresponding axial load value for the first wall and click on “Add Solution” to send it to the Selected Solution. Then enter the new axial load value for the next wall and continue this process until all the product selections are complete.

Maximum Wall Segment Width: This optional input limits the Available Strong-Wall Panels to the maximum width specified.

Available Wall(s) (Manual mode only): Based on the input Design Criteria, all Available Strong-Wall Panels and their allowable loads are listed as an option for selection. The Available Strong-Wall list is independent of the input shear load and instead represents a list whereby any quantity or combination of walls can be selected to resist the shear load.

Solution(s) and Output :

 Possible Solution(s) (Optimized mode only): Up to four possible solutions may be displayed and are designated as Sol # (solution number) in the order of relative cost (lowest to highest material cost).

Selected Solution (Manual mode only):

Add Another Solution: Click on the “Add” button to select wall from Available Wall(s) list, which enters it into the Selected Solution list. You may also double-click on an Available Wall to add it to the Selected Solution.

Clear: Click on the “Clear Selected Solutions” button to entirely remove all previously selected walls in the Selected Solution.

Generate PDF: This button creates a .pdf summary of the wall solution. Under Optimized mode, the output solution is created for the Sol# (solution number) that is highlighted. Under Manual mode, the Output is created for all walls shown in the selected solution list.

Design Anchorage: This option appears at the bottom of the page. If desired, enable the check box next to “Design Anchorage” and select Foundation Type. Anchorage design solutions will then be included in the PDF output.

Notes for Designer: Special notes related to the input variables are displayed in this window during the input process. When the Manual In-Plane Shear tab is selected, the Notes for Designer will indicate whether the Selected Solution is adequate to resist the applied design loads.

Strong-Wall Shearwall Selector-SolutionsStrong-Wall Shearwall Selector-Solution Output

Anchorage Solutions and Output:

 The Designer will have the option to generate an Anchorage Solution appended to the Strong-Wall shearwall solution. If desired, Select Foundation Type, then enable the check box next to Design Anchorage, and the .pdf file will be generated with the anchorage solution on subsequent pages. The designer can choose anchorage solutions based on foundation type for all shearwalls. The two foundation types are slab-on-grade and stemwall and are selected from a drop-down menu. Within each foundation type, the Designer can choose a specific footing type as follows:

Slab-on-Grade Footing Types: Garage curb, slab edge, brick ledge and interior.

Stemwall Footing Types: Garage front and perimeter.

Anchorage solutions are provided based on the shearwall solution(s) selected and the following design criteria: application, load type, actual uplift and concrete strength.

Anchor Bolt: Two anchor bolt solutions are available for the wood Strong-Wall®. They are the PAB7 and the SSTB, both of which are ASTM F1554 Gr. 36 material. The Steel Strong-Wall® uses a single anchor type, SSWAB, which may be either ASTM F1554 Gr. 36 or ASTM A449 (high-strength) material depending on the actual uplift. The Strong-Wall wood shearwall uses a single anchor type, WSW-AB, which may be either ASTM F1554 Gr. 36 or ASTM A449 (high-strength) material depending on the actual anchor tension.

Concrete Service Condition: This criterion refers to whether the concrete is determined to be cracked or uncracked based on analysis at service loads. See ACI 318 for the different reduction factors associated with cracked and uncracked concrete.

Strong-Wall Shearwall Selector-Anchorage Strong-Wall Shearwall Selector-Anchorage Output

The anchorage design .pdf output summarizes all applicable design details including the footing type, minimum footing dimensions, anchor bolt and shear anchorage. The Designer is responsible for foundation design (size and reinforcement) to resist overturning, soil pressure, etc.

Product Information:  Select for more product and application information.

Upload a Saved File: Designer can upload any previously used solution.

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Strong-Wall Shearwall Selector-Info Save Issue

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