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our topic today is titled shear wall analysis made easy force transfer around openings calculator my name is Karen BT and I will serve as moderator for the session our speaker ELISA shooken and I both work for APA the engineered wood Association APA is a non-profit trade association representing manufacturers of a variety of common structural engineered wood products in addition to quality verification and product testing APA conducts research to improve engineered wood construction systems and educates users and specifiers on the products proper use and potential applications before we start today's webinar I need to cover some housekeeping details Elise's presentation will last about an hour to ensure that everyone can hear it clearly we have muted all participants we do encourage you to submit questions by typing them into the questions pane on the control panel on your screen we should have time to answer most questions but if we run short we'll be sure to post a Q&A summary on our website along with the recorded version of today's program we should have those posted in a week or so I'd also like to note that today's webinars approve for AIA and ICC continuing education credits about an hour after the conclusion of the webinar an email will be sent to each in tindy it will include a link where you can get customized AIA and ICC certificates of completion our presenter today is ELISA Hsu Qian engineered wood specialist for APA based in San Francisco California in her role she works with designers building officials and builders on various engineered wood products that are used in buildings today and consults on engineered wood use in construction applications Elise's consulting engineer background involves a wide variety of commercial residential and infrastructure projects she received her degree in architectural engineering with a minor in sustainable environments from Cal Poly in San Luis Obispo for those of you who are just joining us welcome to a piays webinar on the topic of shear wall analysis for force transfer around openings I will now turn the microphone and over to our speaker elisa Shakya you for that introduction Karen as Karen mentioned the topic of today's webinar is shear while analysis made easy the fourth transfer around opening calculator today's learning objectives include an overview of the tools development and a brief history of a pas sta o research the main benefits of the design tool including key features and design capabilities a demonstration of the tools operation and design input and finally we're going to highlight the design outputs and end products that the tool provides so at this point I'd like to take a quick break to launch our first of three poll questions about your occupation if you could please take a look at your screen and answer the poll question about your occupation if you are an engineer an architect a builder or contractor a code official or other I'll give you about 30 to 45 more seconds to fill in your responses if you could we have 15 more seconds to fill in your your occupation okay so based on the responses it seems like the majority of our attendees today are engineers of 80 percent 87 percent being engineers six percent are architects we have zero builders or contractors on the webinar today four percent our code officials and three percent or other so thank you very much for sharing your pool responses as we're looking at addressing shear wall design challenges a lot of the design examples you see tend to be as simple structures with uninterrupted to your wall however in real life this is rarely the case in today's wood frame construction engineers consistently see larger buildings combined with bigger and more numerous window and door openings this construction trend usually translates into reduced areas for lateral resistance throughout the structure there are several ways to address this challenge the American wood Council publication special design provisions for wind and seismic which from now on I will refer to as the spit with provides designers of three acceptable methods for designing which year walls to resist lateral forces the first method is individual full-height segmented rear walls which is the traditional design approach the second is perforated to your wall which is an empirical design method based on the percentage of full height wall segments that are adjacent to opening and the third is fourth transverse shear walls which is referred to in this webinar as force transfer around openings or spao these walls allow for the utilization of the full wall geometry including the sheathed areas above and below openings at this point we're going to look at each of this year well methods in a little more detail for segmented wood shear walls only full height segments are considered and the contribution of the wall sheathing above and below openings is ignored the total height of the wall is used to determine the pier aspect ratio or Heights of width ratio pulldown are typically needed at each end of each shear wall segment to resist overturning forces unless there is sufficient resisting dead load to counteract overturning so in the example shown on your screen here we see four fold down anchors and the base of each full height shear wall needs to be anchored to resist the base year as well in the 2015 bid with there were a few modifications to the aspect ratio adjustment factor which we will cover a little bit later on in today's presentation perforated shear walls account for openings using empirical adjustment factors and strapping around openings is not required however since it is an empirical method its use is limited to specific tested conditions and some imposed code restrictions make it less effective for perforated to your walls hold down bankers are only required at each end of the overall wall length the anchors at the base of full height piers are required to resist both uplift and shear in addition to anchor is among the total length of the shear wall that resists shear similar to the segmented shear walls the height Swiss ratio of perforated shell washer while piers is dependent on the ratio of the total height of the wall over the width of the pier the force transfer around opening or FPA o approach is mentioned in the code but the code does not give specific direction and only references a rational analysis approach based on principles of mechanics in FPA o shear walls the web structural panels transfer this year anchor bolt resists the fighting force at the base of the wall and the hole down which are only located at the ends of the total wall lengths resist overturning generally increased nailing in the vertical and horizontal directions as well as blocking and strapping our common methods used for reinforcement around openings the anchors at the base of the wall should be designed to resist the total shear force divided by the total length of the wall one major advantage of FTA o shear walls is that the heights with aspect ratio is dependent on the height of the opening adjacent to the pier allowing for reduced pier widths to repeat the aspect ratio requirements so at this point I'm going to take a second quick break to go over our second of three poll questions about how often you use force transfer and opening designs so if you can please indicate on the screen if you use it frequently or greater than 50 percent of your project at least once per job or about 0 to 25 percent of the time if you only use segmented or perforated to your walls or zero percent of the time or if this question doesn't apply to you because you don't design wood buildings so again lucky you about 20 more seconds to fill in your responses okay so if we take a look at the responses we can see that most of the attendees only use segmented or perforated shear walls with 43% responding with that zero percent response next we have 36% responding that they use fourth transfer around opening at least once per job 17% of attendees don't design wood building so this question doesn't apply to them and 4% used force transfer on openings frequently all right so thank you again for indicating your responses before I discuss a pas sta o testing I wanted to quickly highlight the adjustment factor changes I became effective in the 2015 bid with instead of applying the aspect ratio adjustment factor only for seismic design now all shear walls that have an aspect ratio greater than two to one that less than 3.5 to one shall be reduced by the adjustment in addition the reduction factor previously was the two times the pier width divided by the pier height but in 2015 a new aspect ratio factor was introduced and it is shown here 1.25 - 0.125 multiplied by the height of the pier divided by the pier with with this new adjustment factor one item to be cognizant of is the restriction of identical wall deflections for multiple shear walls in a line which is mentioned in FID with section four point three point three point four point one there is an exception to this requirement if you apply the old adjustment factor of 2 times the pier width divided by the height for the shear walls with the aspect ratio greater than two to one and less than three point five to one if you're interested in looking more into this requirement you can find more information in this vid with section shown at the top of your screen so now I'm going to review ApS research on FTA Oh shear wall before beginning the lab testing a PA went into the field as well as into design offices to see what was being designed and built based on a field survey in Southern California we found that for multifamily projects 40 to 90 percent of all she replications utilized some amount of ft AO in single-family structures 80% had at least one application on the front or back elevation and if you think about a typical home this makes sense typically you'll see larger openings on the front and back elevations so the need for ft AO was driven by those narrow height to width ratios based on the number and hat size of openings in 2009 a joint research project was conducted by APA the University of British Columbia and the USDA Forest Products lab in order to examine the internal forces generated in with structural panel wood frame to shear walls during a lateral event the goal was to look at the variations in walls with different code allowable heights of whit's ratios different sizes of openings and various levels of detailing the test result in conjunction with analytical computer-based models from the University of British Columbia were used to develop and enhance FTO design methodology and evaluate the accuracy of the calculated forces in the walls using historic FTO design methods in addition to recognizing what was done in the field APA wanted to compare the test results to the rational analysis techniques that are typically used by structural engineers and to identify the most accurate analysis method that match the testing data through APA study of design offices it was found that there are four main techniques that are most commonly used to project the force transfer around opening the dragster analogy cantilever beam analogy and the dieckmann technique the Thompson method is very similar to the deccan method and for the purpose of this webinar I've combined the two methods into one in our discussion so here I'll quickly review each of the techniques the dragster technique is a relatively simple rational analysis method that treats segments above and below the openings as drag stress this analogy assumes that the shear loads and the full height segments are collected and concentrated into the shaded segments above and below the opening for the cantilever beam analogy the wall is broken into segments and moments are sums about the wall ends to solve for the forces at the corners of the opening since the cantilever beam technique treats the forces above and below the openings as moment couples method is sensitive to the height of the sheaths area above and below the opening the dieckmann technique named for the California structural engineer who developed it assumes that the wall behaves as a monolith and internal forces are resolved by creating a series of Freebody diagram although the technique can be tedious for walls with multiple openings many engineering offices have developed spreadsheets or software based on this method a no limitation of the technique is that when the height above the opening is small the resolved shear forces become quite large resulting in the apparent overstressing of the wood structural panel sheathing so at this point I would like to take a moment to cover our third and final poll question if you currently use spao design methods which method do you use so if you could indicate on your screen if you typically use the dragstrip analogy the cantilever beam analogy the deeper method or the Thompson method I'll give us about 30 seconds to fill in your responses okay so now I'm going to close the poll all right so based on the responses we see that about 60% of attendees use the dragstrip analogy ten percent use the cantilever beam analogy twenty five percent use the deccan method and only about four percent currently use the Thompson method alright so thank you again for those poll responses to highlight the variations with the three analysis techniques I wanted to quickly review a design example of a simple wall configuration that you see on your screen in this example we have a two thousand pound shear force at the top of the wall with a two foot three inch width for the first wall peer and a four-foot width for the second peer our window opening is four feet wide by four feet tall and the wall is eight feet tall if we ran through each of the three analysis methods that we talked about the dragstrip analogy the Kin alehrer beam analogy and the dieckmann method we would find that the dragstrip analogy yields a maximum corner force of 493 pounds the cantilever beam technique resulted in a maximum corner force of two thousand five hundred and forty pounds and the dieckmann method resulted in a maximum corner force of nine hundred and eighty six pounds in the interest of time I've skipped over the calculation for each of these methods but if you'd like a copy I can forward you the fully worked out examples if you give me a send me an email after the presentation so as you can see with this wide range of results it begs the question if all of the analyses are correct if they're all incorrect or which one if any we should be using and if you'd like any more information about each of these analogy method you can find a more in-depth review of each of these methods at the references listed here part of what initiated this research was an article in wood design focus written in 2005 by Zeno Martin one a piays research engineer in that article Zeno discusses the dragster analogy in the cantilever beam analogy i Diekman then wrote back to Zeno Martin via the magazine and a closure response to the original article describing the dieckmann technique and the dieckmann technique is also very well described in the Briarwood design textbook the Thomson method is referenced in this yak design manuals which are available on the ICC website and one thing to know as well as in the latest the Ox design manual the Diekman technique is also shown in addition to the Thompson technique so let's take things into the lab and see what we found here is a picture of the typical setup in a piays laboratory based in Tacoma Washington you see that OSB was used for the wood structural panels so for the full height panels in addition to the sections above and below the opening we also have hold downs shown shown here that are replicating the flat strap at the corners of our opening and monitors are attached to the wall and a variety of places the walls were tested using cyclic loading the Curie basic loading protocol all of the walls and the test plan were built twelve feet long by eight feet tall we had 12 different raw configurations that were tested some with spao detailing and some without the wall nailing was Tenpenny common nails at 2 inches on center for all of the walls and we used 1530 seconds performance category structural one OSB so you maybe notice that these sheer wall panels and the fastening is fairly robust and these robust construction parameters were used to maximize the capacity of the heating so that the sta o design capacity would not be limited the OSB seasoning was also used to help dispel some opinions in the industry that plywood is superior to OS b so APA wanted to show that this method is applicable to both plywood and OSB sheathing so to keep things moving forward I am going to highlight only a few of the wall configurations that were tested if you'd like more in-depth information about all of the different law configurations the full research report is available on APA website so just quickly going through some of the wall configurations beginning with one on the upper left-hand corner of your screen you can see we have a 3.5 to one aspect ratio for our rock wall peers giving us 2 feet 3 inch pier lengths on either side choosing was only located on the full height segments with hold downs at each end of those full height piers so we are recreating a segmented rear wall with the wall 1 configuration while 2 is similar to wall one except that now we have sheathing provided above and below the opening similar to a perforated rear wall no strapping or blocking around the opening was provided for wall to wall number 4 shown on the bottom right hand corner of your screen was our first wall that had the full spao detailing wall 4 has the same geometry as well number 1 but now we also have sheathing above and below the openings and only one hold down at the left end and one at the right end of the wall we also have the strap at 8 strapping provided by the hole down on the exterior of the wall while 5 on the upper left-hand corner of your screen is a similar configuration to wall four with the full spao detailing except that now the opening size is increased with a smaller area of sheathing below the opening wall 6 on the upper right hand corner of your screen is similar to wall for as well but with one change when you think about a typical with structural panel the width is usually 4 feet so if you remember back to wall for each pier width with 2 feet 3 inches so in the wall 6 case the piers were installed with the full 4 foot width of the panel and the opening with vodka out of it this is sometimes done in the field and we wanted to see how this configuration compared with our testing to see if having that c-shape panel help to transfer the load around the opening so please just keep this wall succe configuration in mind for later on in the presentation since we will circle back to the C shape panel so again skipping forward to wall 12 well 12 with our last configuration and provided us with some great information for going around multiple openings and asymmetric peers so on the lower right hand of your screen you can see we have different peer links for each full-height wall segment with hole down jet hold downs at each end of the wall and strapping located at the corners of both opening and wall 12 was the focus of our testing and subsequent fko resources since these types of wall configurations hadn't really been studied before so you may have noticed that the whole domes were located at the corner of the opening to transfer the tension forces around the openings on the exterior of the walls that we tested these whole domes were used for ease of replication and monitoring in the lab environment we did additional testing with flat straps shown here for the wall 13 configuration to show that the flat strapping gives the same results as the hold on anchors that we used in our testing so what information was obtained through testing a PA monitored many different aspects of the sheer walls including full down forces and anchor bolt forces forces to collect this information we've studied hysteretic plots of the applied load versus the displacement of the walls and the applied load versus drop forces as well as various cyclic parameters of the wall so now we are going to fast forward to our results so I know this slide is overwhelming with a lot of numbers shown so I wanted to take this opportunity to remind you that this information and the webinar will be available for your reference on the APA website after the presentation so looking more closely at this chart we see a comparison of the measured strap forces and the predicted strap forces per the four design methodologies we discussed earlier when you're looking at this chart the color coding is important we're not going to go through each number in detail but I wanted to point out the areas highlighted in yellow and green you can see each of the wall configurations we tested identified on the left the chart compares measured strap forces that were collected during the test which you see in the first two column in comparisons to common analysis techniques that are used to design ft AO shear walls again you can see that we have the drag stretch technique can I leave her beam technique the dieckmann technique and the Thompson technique comparing the measured strap forces versus what was estimated by each of the analysis techniques for each wall configuration we were then able to study how the analysis results compared to the actual response in the lab so looking first at the yellow color coding it indicates areas or items that were underestimated so if the analysis resulted in strap forces less than what was measured in the lab those numbers are identified by yellow if what was estimated by analysis was overestimated by greater than 300 percent over the response in the lab those results have a green color coding so just glancing at this table we can see quickly that although the direct strut technique is relatively easy to use and simple to follow the results are unconservative for most of the wall configurations that we tested on the other hand we can see that the cantilever beam technique is primarily green particularly on the top force or the force above the opening so when we compare our analysis results what was measured we see that the cantilever beam technique is ultra conservative so this becomes an issue when we try to install an ax system that is not only effective but also efficient that leaves us with the dieckmann or the Thompson technique while these techniques aren't the most straightforward to use the main takeaway is that these methods really are the most accurate when compared with the wall configurations that APA tested one thing I just wanted to point out again on wall succe which again is the C shaped panel configuration was that this is the only wall where the drag strut technique was not only accurate but more accurate than the other techniques because it was within that 100 to 300 percent accuracy this is because the panel was actually working to transfer some of that tension force around the opening which made it more closely resemble what was estimated per the drag stret technique so the C shaped panel does provide us with some design assistance and is something to consider moving forward so I'd like to take a moment to look more closely at some of the local responses of our tested wall configurations the response curve shown here show a comparison of walls 1 & 2 for the applied load versus displacement for the segmented walls which is represented by the blue line and the perforated walls which is represented by the red line so when you compare the two you can observe that the red line has an increased stiffness versus the blue line so again our perforated your walls will have an increased stiffness over our segmented to your wall looking at the wall for configuration which again includes the spao detailing we have relatively narrow piers with a deep fill for this configuration I wanted to highlight the response curves of the strap forces versus the applied load each of the 4 colored lines shown plotted corresponds with the four strap locations of the window corner in this case the bottom-left corner saw the largest draft forces and then when we look at comparing wall for with wall five which again has increased opening size from Lahore you can see that the strap forces increased as the opening size increases when you compare well floor to wall five side-by-side you see that the enlarged opening causes an increase in strap forces and a decrease in stiffness you can see here that the maximum strap force for wall for was just over eight thousand pounds whereas the maximum strap forest for wall five was around ten thousand pounds when looking at the global response we found that there was a correlation between opening size and strap forces we saw that strap the wall five had a reduce stiffness is a larger opening than wall for but both wall four and well five demonstrated increased stiffness and strength over the wall configurations that did not include fko detailing APA found that larger openings resulted in both lower stiffness and lower strength overall from the testing we saw that the relatively brittle nature of the perforated shear walls with the testing often resulting in sheathing tearing there was also a concentration of forces in the areas that is highlighted or in pink or red on your screen which drives this year type and nailing the variable stiffness between peers adjacent to the opening and the areas below the opening caused significant damage in the areas highlighted in blue and this was due to a banging effect of the variable stiffnesses so looking back again at that c-shape panel configuration that we discussed with wall six we found that the C shape around the ends of the openings did reduce the amount of strapping required using a c-shaped panel you may be able to eliminate strapping based on the strap forces that are calculated but special care should be taken in the wall detailing if this is going to be utilized as time APA hasn't done any additional analysis on the contribution of the c-shaped panel but that is something that could be done for per your own rational analysis so I'd like to touch on one last topic before reviewing our testing conclusions as APA has been hearing our FTA o information we've been receiving a lot of questions about if the straps need to be continuous above and below the openings as we saw in the previous slide we may not even need straps at all if a c-shape panel is used to resolve the corner forces but when straps are provided what is the required length of strapping so the speed with section four point three point five point two addresses collection requirements and this refers to full length horizontal elements such as top plays of your walls or drag stress that are acting as a continuous collector or a diaphragm boundary element that collects the diaphragm hears and transfer them into the line of lateral resistance the difference between your collectors and the strapping above and below the openings is that the strapping does not resist shear load instead the strap forces are dependent on the calculated internal tension and compression forces of the wall at the corners of the opening therefore the straps would only need to be long enough to allow for the development of the tension load so here are our conclusions and looking at the twelve wall configurations that we tested we found that the walls of the full spao detailing resulted in a better global response the stiffness of the wall increased as well as the strength for an F ko shear wall in comparison to just a segmented or perforated approach when looking at the for rational analysis methods we recognize that the drag stretch technique was consistently unconservative the cantilever beam technique with ultra-conservative and the dieckmann and thompson methods both provided reasonable agreement with the measured strap forces moving forward with these results the hope was to provide better guidance for engineers by validating the techniques currently in use and developing new tools to facilitate SEO shear wall design before I move on to the advances that have taken place since the testing was completed I wanted to note that there is a report located on APA website which covers the research and results in more detail if you'd like more information you can find the report by searching force transfer or form M 410 on APA publication cap of the website so looking back at wall 12 once again this configuration has the full spao detailing with multiple openings and asymmetric pier width we only have hold down at each end of the wall with sheathing and strapping and blocking provided above and below the opening moving forward the question became how do we provide an accurate analysis method for more complex wall configuration the information from a pH testing and results were condensed into a theok or structural engineers Association of California white paper for the 2015 convention preceding Tom Staggs one of AP AIDS research engineers and Tacoma and Karen Beebe who is our moderator for today's webinar wrote a paper titled advancements and forced transfer around opening for web frame structure wall this paper really focuses on wall 12 and was the basis for APA new technical note on design for force transfer around opening which we will discuss shortly after initial testing determined that the dieckmann technique was the most accurate analysis method to estimate the forces in the shear wall a use this approach as a base to expand the methodology to incorporate multiple openings and asymmetric peers this methodology is based on the following key design assumptions the first is that the unit shear is equivalent above and below the openings the corner forces are based on the unit shear above and below the openings and only the wall periods adjacent to that specific opening and the tributary length of the opening is the basis for calculating the shear to each wall pier this tributary length is the ratio of the length of the pier multiplied by the length of the opening it is adjacent to then divided by the sum of the lengths of the pier plus the length of the pier on the other side of that specific opening the deepen method also assumes that the here to each wall pier is the total shear divided by the length of the wall multiplied by the sum of Sapir lengths plus the tributary width of the adjacent opening then divided by the pier lengths the unit shear and the corner zones is equal to subtracting the corner forces from the panel resistance and the panel resistance is equal to the shear of the pier multiplied by the pier of length so one of the best parts of the deep end method is that the final conceptual key is that once this segment years have been calculated the design can then be checked by summing this years vertically along each line the first and last line should equal hold on force and the rest should sum to zero so this is a quick way to go back and check your work at the end to know if you've done your math correctly testing data was also used to analyze the overall deflection of the sjo wall system which verifies that the sheathing below the openings aided and resisting the overall deflection of the wall the wall deflection assumption is that the total deflection of the FTA o shear wall is equivalent to the average deflection of each wall pier in both the positive and negative directions the wall pier height also varies depending on the deflection direction and amount of Shaving below the opening so for example you can see in the images shown starting with the upper left-hand image that the positive deflection of wall pier 1 is determined using the height measured from the bottom of the opening to the top of the wall due to the resistance of the wall sheathing below the opening where as you can see in the bottom right-hand corner that the negative deflection of wall pier 1 is determined using the full wall height to attain the most accurate fastener deformation variable the basis of the testing was completed using the four term deflection equation from the 2015 International Building Code or IBC equation 23 to the three term deflection equation provided in the food Wiz which is equation 4.3 - one can also be used but the deflection calculations must be consistent throughout your design in the time after a ph testing was completed the information gathered from the results were used to develop a couple design resources to facilitate sko shear wall design all of these design resources are located for download on the APA website at WWE pa Widow RG / FPA oh one thing to note when downloading these resources from a piays website is that you need to register and create an account before accessing the tool which we will cover at the end of today's webinar two of the resources I wanted to highlight in today's webinar include a piays technical note design for force transfer around openings and a PA force transfer around opening calculator both of these resources were released in January 2018 and are available for download at the webpage shown or APA way org slash FTA oh the technical note design for force transfer around openings also known as forum T five five five presents a rational analysis for applying ft AO to walls of asymmetric piers and multiple opening this publication was developed based on a piays results from the wold club configuration from the testing that we were discussed previously the technical note provides a design example of an FTA Osher wall with two window openings historically sta o design examples have been completed showing symmetric wall peers around a single opening the design example in the technical note was intended to illustrate a more practical application of spao for walls with multiple openings and a symmetric wall pier widths as a companion to the technical note APA also developed an excel-based forced transfer around opening calculator this calculator is a tool for engineers to use and analyzing shear walls with up to three openings and is based on the design methodology developed by Diekman I listed the calculation outputs here which we will cover in more depth later on I am now going to walk through some of the features of the tool the first tab on the spreadsheet is for instructions and definitions this tab provides definitions of the variables and inputs needed for the shear wall and deflection calculation the design example tab of the spreadsheet shows how the design example from FTA Oh technical note can be solved using the calculator using the spreadsheet in conjunction with the tech note users can work through how to properly insert the design parameters into the calculators input cells and follow along with the design process the calculator is divided into three worksheets one for shear walls with one opening sure well this - opening and share walls with three openings to use the calculator users insert the required information into the orange input cells indicated here by the red arrows some of the parameters required for the shear wall design include the applied lateral force the dimensions of the full height wall pairs and the dimensions of the sheathing above and below each opening based on these inputs the calculator then automatically determines the overall height and length of the wall one thing I wanted to point out here is a limitation of the calculator in which it assumes that all of the openings have the same height if your shear wall has multiple openings of varying Heights you would need to use the worst-case scenario or the largest opening when inputting your opening dimensions using the dimensions for the shear wall layout the calculator is then automatically determines the wall pier aspect ratios indicated here by the area box in red if the aspect ratio is greater than the two-two-one height to width limit the calculator determines the required adjustment factor and adjust the required shaping capacity accordingly as you can see in this example all of the peers meet the aspect ratio requirements so that no adjustment factor needs to be applied this highlights one of the advantages of using sta o2 to design shear walls where you only need to consider the height of the adjacent opening when determining the Heights with ratios so limiting the cases where you would need to apply it that dress adjustment factor based on the lateral here and wall configurations the calculator then follows the conceptual keys that we developed from the dieckmann method in order to analyze the shear wall both the spreadsheet and the technical note list the design steps shown here but you can follow along with the calculators analysis process so some of the key steps that I wanted to highlight include step one which determines the hold on forces step for the strap forces and step two step six and step nine check the maximum shear for your panel design as mentioned previously one of the advantages of the defend method is the assurance from being able to check your work at the end the spreadsheet includes an area that sums the vertical shear along each line so that users can check their work this summary table shown from the spreadsheet shows that the calculation for lines 1 and 6 equals the hold on forces and then intermediate water lines shown on the right hand side of your screen sum to 0 this brings us to the design summary section which includes the maximum shear force to determine the required caving capacity the required horizontal strap force for the tension straps above and below the openings and the maximum hold on forced 4 of uplift resistance so if light yellow boxes shown on your screen highlight the design summary output provided by the calculator sko calculator also determines the shear wall deflection so after you enter project specific parameters including the sheathing material with n post information fastener and hold on information the spreadsheet will then calculate the overall wall deflection using that methodology that we discussed earlier with the positive and negative deflection the deflection is calculated determining the average of the positive and negative deflection values for each peer using the 4 term deflection equation from the 2015 IBC as well as the three term deflection equation from sections 4.3 - one of the spit with so again the calculator provides both of these deflection calculations and you would need to keep those deflections calculations consistent with either the four term or three term equation as you're working through your design analysis process for your entire shear wall system the calculator final design output includes the spao shear wall analysis with the full design equations shown a summary of the final design requirements and the total calculated deflection the analysis results but on two three pages and can be printed directly from Excel or saved as a PDF file to be included in the final calculation package one thing to note is that the spreadsheet can be used for multi storey shear walls but you will have to work through the calculator story by story and consider the cumulative effect of horizontal shear and overturning as you move from story to story in conclusion the spao tool is intended to help engineers design for challenging law configurations by taking full advantage of shading above and below opening and increasing design flexibility to allow for larger window openings at this point I'd also like to highlight some of the benefits of using sta shear walls as I already mentioned structural engineers gain the design assurance from being able to check their work at the end of this year while analysis to make sure that the sum of the vertical lines at the end as well equals the hold on force and the some of the intermediate vertical lines equals zero even though we walked through a lot of conceptual Keys design tools like the FBO calculator by APA just release can be programmed to facilitate and simplify the design process taking advantage of the sheathing around opening gives the architect greater flexibility for narrow wall piers as you're able to determine the heights with ratio that's simply based on the height of the opening of the pier is next to instead of the full height of the wall and as our heights of our walls increased to 90 10 C and Beyond it can really help that we are able to use that reduced height when determining if our wall meets the heights with ratio requirements there is also an advantage when you're building envelope has an uninterrupted plane when we look at durable designs and minimizing moisture intrusion having a continuous using is going to aid in that continuous drainage plane as well as minimize air infiltration one that EPA's most powerful tools is our website and all of the resources that I mentioned today can be downloaded from the website with a free registration the link shown here APA would org slash FPA o will take you directly to our FTA web page where you can access the technical note and the calculator or you can always visit our main page at WWE pa would you are G so at this time I'm going to turn it back over to Karen who has been monitoring questions throughout the session if you have any questions please type them into the panel on your screen I've also listed my contact information if you have any questions after the webinar or if you need help accessing the design resources that we cover today Thank You Elise our first question and our first couple of questions are more housekeeping items so I'll go ahead and answer those for you the first question that came in are the slides for the webinar available for downloading and as I mentioned before we will have a recording of the webinar available on our web page in about a week or so you can also reach out to a lease or to our help desk directly if you're looking for a PDF of the slides for your use another question is what spreadsheet software does the calculator work on and this is a tool that's built for Excel another question lease is there a minimum height required for the areas above and below the openings a good question so there are no minimums that must be applied for the height above or below opening the only limitation is being able to effectively resolve the forces in those narrow sections as the height above and below opening decreases which can become challenging as those areas get smaller and smaller thank you and can you use the FT AO calculator at door openings yeah I received this question a lot but since a PA calculator is based on the diekmen method doorways must be omitted from the line of resistance this is because if you remember back to the first design assumption that we covered for the D Quinn method the shear wall above and below the openings is assumed to be equal so there must be sheathing provided below the openings great and is there a minimum allowable width for the full height Spears the spit was currently list a minimum pier width of 24 inches but APA has been testing to justify a minimum period sit down to 18 inches provided that the aspect ratio of the pier is 3.5 to 1 or less there is some information that covers this minimum pier which in the T forms t-55 5 or the technical note on designing for forced transfer around opening so if you have questions about that or want to reference the minimums here which you can look to that document as well thank you and a couple of people asked the same question worded a few different ways but the strapping around the openings can get in the way of window installation what is a solution yeah that's a great question also so one solution that several people have been using is to install the strapping on the inside of the wall so it doesn't matter which side of the wall the strapping isn't on it can be installed on the outside or the exterior side as we've have shown in our examples or it can be installed on the inside of the stud but if just dropping is installed on the interior side specialist detailing is required the blocking should be the full depth of the wall says so that this trap can be installed to the blocking with the fasteners that are required by the strapping manufacturer also the nailing pattern from the exterior sheathing into the blocking should be the same nailing as what was specified by the strap manufacturer as well okay what force do you use to design the Anchorage along the base of the shear wall so the required Anchorage along the base of a fko shear wall would be equal to the horizontal shear force divided by the total length of the shear wall and a related question and let me see here does the spreadsheet differentiate between designing shear walls for seismic or wind yeah so as far as the number reported for the design summary and kind of working through the calculations the calculator does does not differentiate between seismic or wind forces or allowable stress design or lrfd as long as the designer has applied all of their adjustments prior to entering the values into the calculator it will provide the mathematical solution to the forces for each output so all of the factors would have to be completed by the designer prior to entering them into the spreadsheet or alternatively the designer could use unadjusted to your values and then receive the nominal output for the requirements and then they would have to design their shear wall design summary values accordingly and another related question for design purposes are the values being taken as allowable stress design or lrfd so the the calculator does not differentiate between allowable ASD or lrfd so again the the designer would have to factor their values independent of using the calculator either before the calculator values our input or after their design summary values our output through the design summary how should we interpret results for large openings when shear and Corner zones become negative yeah that's what another really good question so in theory of the the forces generated in the corner can be negative the calculation of the unit shear in the corner zones is simply another way to close out the solution and make it make sure it works so there isn't really exactly a real-world application but all this means is that the assumed direction of this years in the corner was not correct so this would happen when the pier is relatively narrow the window opening is relatively tall and to hold on horses are not large and do we need to check the bottom plate for compression so the bottom plate would need to be checked for compression independent of the calculator the calculator does not check this so yeah the similar question was also related to checking for the the wooden posts and another question was asking about the nails and spacing for the applied forces on the panels is this something that regulator does so the calculator does not check the n post capacity this spreadsheet only includes and post information for the deflection calculations and the required sheathing capacity is shown so that you or the designer can and specified that the sheathing thickness and nailing is adequate to account for those required sheathing capacities but the calculator does not check to make sure that the sheathing design is sufficient thank you and then it's the shear and piers of an FTL wall the design shear for nailing or is it the highest year perhaps above or below the openings the design shear the calculator check shears in all of the areas of the wall so above and below openings and adjacent openings and take those maximum shear forces to determine the required sheathing capacity and I think we have time for one more here how do you handle walls with more than three openings so unfortunately the APA calculator was only generated four walls up to three openings and so if you are designing a wall with more than three openings then you would need to adapt the information from the calculator and develop your own spreadsheet to account for more opening great Thank You Elise so powerful tool for everyone to be able to download I want to also remind everyone on the line that if you have any technical questions on any topic related to the use of engineered wood products don't hesitate to contact the APA help desk as shown on the slide as well before we conclude I'd like to touch on three quick things related to a short survey CEUs in upcoming webinars we'd really appreciate receiving your feedback via the survey that you will receive shortly so please take a minute and fill that out also don't forget to download the aia or ICC certificate of completion from the links and the follow-up email that will be sent to you an hour after the webinar ends and finally make sure that you are signed up to receive our APA update newsletter so that you will be notified of our next webinar as well as future webinars and updates to APA publications and standards to receive it all you need to do starting from the homepage of our website is to click on sign in in the upper right hand corner of the page in the menu that drops down simply select register from there you will need to let us know what you specifically like to receive which in this case the APA update newsletter as mentioned earlier a recording of today's webinar and answers to the questions that were asked will be posted at APA would RG in a week or two and with that I'd like to thank you all for attending have a great day you