What’s New in the ACI 440.2R-17?

The wait is over. The ACI 440.2R-17 Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures is now available. The following post will highlight some of the major changes represented by this version of the document.

It’s been a long road and countless committee hours to get from the last version of ACI 440.2R-08 to this document. While there are multiple smaller changes throughout the document, the most notable update is the addition of Chapter 13 – Seismic Strengthening.


The new seismic chapter addresses the following FRP strengthening scenarios:

  • Section 13.3 – Confinement with FRP
    • This section includes all of the following: general considerations; plastic hinge region confinement; lap splice clamping; preventative buckling of flexural steel bars.
  • Section 13.4 – Flexural Strengthening
    • The flexural capacity of reinforced concrete beams and columns in expected plastic hinge regions can be enhanced using FRP only in cases where strengthening will transfer inelastic deformations from the strengthened region to other locations in the member or the structure that are able to handle the ensuing ductility demands.
  • Section 13.5 – Shear Strengthening
    • To enhance the seismic behavior of concrete members, FRP can be used to prevent brittle failures and promote the development of plastic hinges.
  • Section 13.6 – Beam-Column Joints
    • This section covers a great deal of recent research on the design and reinforcement of beam-column joints.
  • Section 13.7 – Strengthening Reinforced Concrete Shear Walls
    • This section provides many recommendations for FRP strengthening of R/C shear walls.

Simpson Strong-Tie Can Help

We recognize that specifying Simpson Strong-Tie® Composite Strengthening Systems™ (CSS) is unlike choosing any other product we offer. Leverage our expertise to help with your FRP strengthening designs. Our experienced technical representatives and licensed professional engineers provide complimentary design services and support – serving as your partner throughout the entire project cycle.

For complete information regarding specific products suitable to your unique situation or condition, please visit strongtie.com/css or call your local Simpson Strong-Tie RPS Specialist at (800) 999-5099.

Upcoming Free Webinar: Advanced FRP Design Principles

Join us live on July 25 for the second interactive webinar in the Simpson Strong-Tie FRP Best Practices Series: Advanced FRP Design Principles. In this webinar we will highlight some very important considerations during the FRP design processes. This will include topics such as the latest industry standards, proper use of material properties, and key governing limits when designing with FRP. Attendees will also have an opportunity to pose questions to our engineering team during the event. Continuing educations units will be offered for attending this webinar. 

Advanced FRP Design Principles

In this free webinar we will dive into some very important considerations including the latest industry standards, material properties and key governing limits when designing with FRP.


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!

How Are DECK-DRIVE™ DWP Screws Load-Rated?

Experiential learning — has it happened to you? Certainly it has, because experiential learning is learning derived from experience. It happens in everyday life, in engineering and in product development, too. For example, experience has taught us that after a product is launched, our customers will find applications for the product that were never expected or listed in the product brief. Also, experience has shown us that larger fasteners tend to be placed in applications that have greater structural and safety demands.

When the larger Deck-Drive™ DWP screws were manufactured, we decided that they should be marketed as “load-rated” screws because they were big enough to support physically large parts and would be expected to provide structural load resistance.

So what is a “load-rated” screw? To Simpson Strong-Tie, a load-rated screw is a threaded fastener that has controlled dimensions and physical properties, as well as validated connection properties.  Load-rated fasteners are also subject to the same quality inspection that would occur if they were undergoing an evaluation report.

The products in the focus of this blog are Deck-Drive DWP Wood stainless-steel tapping screws. They are made from stainless steel (Types 305 and 316) and are particularly interesting because they have a box thread design feature. What is a box thread and what are its benefits? A box thread is a thread that is square rather than round. It is formed by rolling (not a trivial tooling challenge) like a standard thread. The box thread is preferred for some applications in part because of the low torque required to install the screw; that is, the installation demand is low relative to standard threads of the same pitch (number of threads per inch). You can easily see the box thread by looking from the point of the screw toward the head. The square corners of the box thread rotate at a defined angle, giving the threaded length a twisted appearance. The box thread is also used on the Timber-Hex SS screws. See Figure 1 for an illustration.

Figure 1. Phone photo showing box thread on a DWP screw (No.12, 4 inches long). These screws have a flat head, and this size has a T-27, six-lobe drive recess.

When we load rate a fastener, ICC-ES AC233 (Acceptance Criteria for Alternate Dowel-type Threaded Fasteners, 2015) is the guiding document. Essentially, we do everything that would be done if the product was going into an evaluation report. The testing uses representative products and is witnessed by a third party, and every test report is reviewed and stamped by a professional engineer. The DWP screws that are fully load rated are No. 12 and No. 14 that are three to six inches long. This means that we have evaluated by test the shear and tensile strengths, bending yield strength, head pull-through resistance, withdrawal resistance and certain logical lateral shear configurations of these models. The connection properties are developed in at least three species combinations of wood representing a range of specific gravities. Each cell in the connection load matrix is a reference allowable value based on a mean of at least 15 tests that is subject to a precision of five percent at a 75-percent confidence level. Table 1 is snipped from the prepublication spreadsheets.

While we were working on the No. 12 and No. 14 screws, we also realized that No. 10 DWP screws often require withdrawal loads because they are used in decks and docks to fasten the decking to the structural frame. You can see in Table 1 that the withdrawal loads were included for No. 10 DWP screws and the related properties, because uplift resistance is often engineered for those applications.

What is the test method for each property in the load table? See Table 2 for the test method used for each property and the related data for that property. The reference allowable shear loads shown in Table 1 represent more than 1,200 individual tests, and each test includes wood specific gravity, moisture content and continuous load-displacement data from start of test to past ultimate load.

Table 1. Reference allowable properties for the DWP load-rated screws.

Table 2. Test methods used to evaluate the properties of load-rated screws per ICC-ES AC233.

Load rating screws is a big job, and it creates an elevated continuous quality-monitoring obligation. However, our experience has taught us that the engineering community needs information and reference properties that can be relied on when specifying, and thus working with load-rated screws makes it possible to put your stamp on a design with confidence.

We look forward to hearing from you about load-rated fasteners, because we learn from you every time you contact us.

Design More with Our New Steel Deck Diaphragm Calculator App!

People are always innovating new things! There are always new tools, software, apps or, more recently, digital assistants to help us organize our life! Here’s something I want to share with you. Recently my family bought Google Home, and both my boys (ages 8 and 5) are constantly exploring it and testing its capabilities: “Hey, Google, play this music” or “Hey, Google, what time is it?” or “Hey, Google, repeat ‘Nathan is bad.’” While Google Home helps them with the former requests, it simply says, “I am still learning,” in response to commands like “repeat ‘Nathan is bad.’”  It’s funny to see them experiment and come up with creative ideas to use the tool. Many of us appreciate tools that help us be more organized or increase our efficiency or that are simply fun to use. Our new revised diaphragm calculator for designing metal decks is our attempt to help the engineering community get more done in less time.

So What Are the Updates and Revisions?

We have updated our design software to design per Canadian Standards like CSA136 and to design per Limit States Design. The app is so easy to use that you can design a steel deck diaphragm in minutes! The software designs steel decks for both shear and uplift forces acting on the deck and provides tables with diaphragm shear capacities for a given deck span using Simpson Strong-Tie deck fasteners that conform to Canadian codes and standards. These fasteners have an evaluation report, IAPMO UES ER-326, are recognized in SDI (Steel Deck Institute) DDM03 Appendix VII and IX and the CSSBI (Canadian Sheet Steel Building Institute) Design Manual and have FM approvals.

Overview of the App

When you open our diaphragm design software, Steel Deck Diaphragm Calculator, there is an option to “Select your Country.”  You can choose to design for US standards, in which case you select the USA option, or you can select Canada Imperial or Canada Metric, which are new additions. The app has three sections: (1) Optimized Solutions, (2) Diaphragm Capacity Tables and (3) Other Diaphragm Tables. All three options are available for the USA option. The Optimized Solutions help you to design a deck for any given shear and uplift. You can refer to our previous blog, Design Examples for Steel Deck Diaphragm Calculator Web App, for some examples on how to design steel decks using the Optimized Solutions selection. Diaphragm Capacity Tables are available to the USA and both Canada selections. Other Diaphragm Tables is available only to the USA selection.

Metal Deck Diaphragm Design Using Limit States Design (LSD)

When you select Canada for the country, you will have the option to select Diaphragm Capacity Tables as shown in the screen shot below. You can generate diaphragm shear tables by entering:

  1. Steel Deck Information: In this section, you select the type of the deck, the design method, the load type you would like the tables to be generated in and the deck thickness. You can enter uplift if you would like to design the deck for combined shear and tension, or leave the net uplift as zero if you are generating shear-only tables.
  2. Quik Drive Fastener Information: In this section, you input information about the structural and side-lap fasteners.

Click the Calculate button to generate the tables.

A PDF copy of the tables can be generated in either English or French.

This easy-to-use design software can be used by the designers, specifiers or erectors to generate the tables required. More information about our X series of screws (including XL and XM), tools and the required industry approvals for designing the profiled deck diaphragms can be found on our website at strongtie.com.

Please try out the app and let us know your comments and feedback so we can continue to improve our software to better serve your needs!


Why You Should Specify Stainless-Steel Screw Anchors When Designing for Corrosive Environments

Figure 1. Spalled concrete below a concrete bridge.

I was driving under a concrete bridge one nice clear day in Chicago, and I happened to look up to see rusted rebar exposed below a concrete bridge. My beautiful wife, who is not a structural engineer, turned to me and asked, “What happened to that bridge?” I explained that there are many reasons why spalling occurs below a bridge. One common reason is the expansion of steel when it rusts or corrodes.

This week’s blog will briefly explain the corrosion process and why concrete spalls when the embedded metals corrode. Corrosion may be defined as the degradation of a material as a reaction to its environment.1. As described in our previous SE Blog post, “Corrosion: The Issues, Code Requirements, Research and Solutions” dated January 3, 2013, corrosion of metallic surfaces is an electrochemical process. Because of moisture evaporation, concrete is a porous material. Water and oxygen molecules enter the pores of the concrete, and an electrochemical process occurs with the carbon-steel bar. The iron in the steel is oxidized, which then produces rust. A buildup of rust products at the surface of the carbon-steel bar exerts an expansive force on the concrete. Based on the amount of oxidation, the rust products of steel can occupy more than six times the volume of the original steel.2 Over time, further rust occurs and surface cracks will form. Eventually spalling will occur, exposing the rusted carbon steel bar. (See figure 1.)

Figure 2. Stages of corrosion.

Just as with reinforcing bars below a concrete bridge, cracking and spalling can occur when a carbon-steel anchor is used adjacent to a concrete edge. Simpson Strong-Tie® has many anchorage products that can be used in these conditions to prevent cracking. One specific product is the new stainless-steel Titen HD® screw anchor. This new innovative screw anchor is made up of Type 316 stainless steel. As seen in Figure 3, Type 316 stainless steel has a high level of resistance. This makes the stainless-steel Titen HD an excellent choice when it comes to an anchorage solution in corrosive environments. These environments include wastewater treatment plants, exterior handrails, exterior ledger attachments, stadium seating, central utility plants, and kitchens just to name a few.

Figure 3. Simpson Strong-Tie level of corrosion by material/coating.

Unlike expansion anchors, screw anchors require the leading threads to cut into predrilled holes. This can be easily achieved with hardened carbon-steel cutting threads. Stainless steel is not hard enough to cut into concrete. The new innovative stainless-steel Titen HD solves the problem by brazing heat-treated carbon-steel cutting threads to the surface of the stainless-steel tips of the screw anchor. (See figure 4.) These carbon-steel threads are hard enough to cut grooves into the surface of a predrilled hole, allowing the anchor to be installed with ease. The volume of the carbon-steel cutting threads is less than 1% of the stainless steel, reducing the buildup of rust that eventually spalls the concrete edge. Other stainless-steel screw anchor manufacturers in the market have a bi-metal product that attaches a full carbon-steel tip. This bi-metal screw anchors contain up to 18% carbon steel. Such a large amount of carbon steel can expand up to six times its volume when it corrodes and can spall the concrete when used adjacent to an edge.

Figure 4. Carbon-steel cutting threads.

Figure 5. Graphic representation of spalling in concrete adjacent to an edge.

When designing an anchorage solution for your next job in a corrosive environment, the stainless-steel Titen HD will provide the best resistance for corrosion, and also give the ability to drive these anchors into the concrete with ease. More information about the product can be obtained by visiting strongtie.com/thdss.

  1. Corrosion Technology Laboratory (https://corrosion.ksc.nasa.gov/corr_fundamentals.htm).
  2. Galvanized Rebar (http://www.concreteconstruction.net/how-to/repair/galvanized-rebar_o).

Stainless-Steel Titen HD®

The Next Era of Stainless-Steel Screw Anchor For Concrete and Masonry.

What Makes a Good Training Facility?

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

When it comes to training, 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.

Code Update: Revisions Finalized for the 2018 IRC

This blog post continues our series on the final results of the 2016 ICC Group B Code Change Hearings. This post will focus on approved changes to the International Residential Code (IRC) that are of a structural nature. The changes outlined here will be contained in the 2018 IRC, which is expected to be published in the fall of this year.

In Chapter 3, the seismic design category / short-period design spectral response acceleration maps will be updated to match the new USGS/NEHRP Seismic Maps. These new maps are based on the worst case assumption for Site Class. Significantly, a new set of maps will be provided in Figure 301.2(3) “Alternate Seismic Design Categories”. These are permitted to be used when the “soil conditions are determined by the building official to be Site Class A, B or D.” See page 29 of the linked document for the new maps and a good explanation of the changes that will be occurring in various parts of the country. In addition, the ICC Building Code Action Committee authored a reorganization of the seismic provisions of Chapter 3 to try to reduce confusion.

Another change in Chapter 3 will clarify that guards are only required on those portions of walking surfaces that are located more than 30 inches above grade, not along the entire surface. To bring consistency with the IBC, another change will require that staples in treated wood be made of stainless steel.

A broad group of parties interested in deck safety, known as the Deck Code Coalition, submitted 17 different code changes with revisions to Section R507 on decks. Of those, 12 were approved, making significant changes to that section. The various approved changes included the following: a complete re-write of that section; new/clarified requirements for deck materials, including wood, fasteners and connectors; clarified requirements for vertical and lateral connections of the deck to the supporting structure; new requirements for sizes of deck footings and specification that deck footings must extend below the frost line, with certain exceptions; clarification for deck board material, including an allowance for alternative decking materials and fastening methods; adding new columns to the deck joist span table that show the maximum cantilever for joists; adding the allowance for 8×8 deck posts, to allow notching for the support of a three-ply beam; and clarification of the deck-post-to-footing connection.

In Chapter 6, a new table permitting 11ʹ- and 12ʹ- long studs was added. In the 2015 IRC, load-bearing studs were limited to 10 feet in length. A new high-capacity nail, the RSRS (Roof Sheathing Ring Shank) nail was added as an option for fastening roof sheathing. This nail will become more widely used once the higher roof component and cladding forces from ASCE 7-16 are adopted. The rim board header detail that was added for the 2015 IRC was corrected to show that hangers are required in all cases when the joists occur over the wall opening.

There were several changes made to the Wall Bracing Section, R602.10. The use of the 2.0 increase factor was clarified for use when the horizontal joints in braced wall panel sheathing are not blocked. Narrow methods were added to the column headings for the wind and seismic bracing amount tables, to make them consistent, and the methods for adding different bracing were clarified. When using bracing method PFH, the builder can omit the nailing of the sheathing to the framing behind the strap-type holdown. Finally, offering some relief for high-seismic areas where brick veneer is used, an allowance was added to permit a limited amount of brick veneer to be present on the second floor without triggering the use of the BV-WSP bracing method.

In Chapter 8, the requirements for a “stick-framed” roof system were completely re-written to make such systems easier to use.

A couple of significant changes were made to the prescriptive requirements for cold-formed steel framing. The requirements for the anchorage of cold-formed steel walls were revised, and the wind requirements for cold-formed steel framing were changed to match the new AISI S230 prescriptive standard.

Finally, it may be helpful to mention some of the proposed changes that were not adopted. While the new ASCE 7-16 was adopted as the IRC reference standard for loads as part of the Administrative changes, several changes to the IRC to make it consistent with ASCE 7-16 were not approved. A change to update the IRC wind speed maps, roof component and cladding pressures, component and cladding roof zones, and revise the remainder of wind-based requirements to match ASCE 7-16 was not approved. Similarly, a proposal to increase the live load on decks, from 1.0 to 1.5 times the occupancy served, was denied.

Once the IRC is published, it will be time to start a new code change cycle once again, with Group A code changes due January 8, 2018. The schedule for the next cycle is already posted here.

What changes would you like to see for the 2021 codes?

Sneak Peek: Our New and Improved Deck Design Guide

One of the ways I get through winter every year is by looking forward to the weekend in March when we set our clocks ahead and “spring forward” into Daylight Savings time. Some people don’t like this change because of the lost hour of sleep, but to me it means the weather shouldn’t be cold for much longer.

The coming of spring means getting to walk to the car in daylight at the end of the workday. It also means getting the garden started for the year and spending more time outside in general.

Of course, I’m not alone in being happy to see winter go.

In the residential world, the phenomenon of “deck season” coincides with this time of year.  Homeowners with decks are getting ready for summer by giving their decks a cleaning and looking them over for any needed maintenance. Now’s the time that new or replacement decks are being planned and built to be enjoyed for the rest of the year.


It’s no coincidence, then, that our deck-code guide has been updated again in time for warmer weather. The Deck Connection and Fastening Guide goes detail by detail (ledger connection, joist-to-beam connection, beam-to-post connection, etc.) through a typical deck and identifies the relevant building-code requirements (2012 and 2015 IRC/IBC) and connection options.

Our deck-code guide can be a helpful reference to an engineer who is just getting acquainted with decks, and can also bring you up to speed on revisions to the IRC that can necessitate engineering changes to even a relatively simple residential deck. Multilevel decks, guardrail details, ledger details and foundation challenges are all examples of things a deck builder could call you for assistance with.

For more information on resources available to engineers on deck design, feel free to consult my previous blog article, Wood-framed Deck Design Resources for Engineers.

The Deck Connection and Fastening Guide


This guide provides instructions on how to recognize defects and deficiencies in existing decks, and guidance for building a strong, safe, long-lasting new or renovated deck structures.

For more deck-related blog posts, check out the links below:

5 Steps to a Successful Soft-Story Retrofit

Last year, I gave a presentation at the annual National Council of Structural Engineers Associations (NCSEA) Summit in Orlando, Florida, titled “Becoming a Trusted Advisor: Communication and Selling Skills for Structural Engineers.” As this was a summit for the leaders of the structural engineers associations from across the country, I wasn’t sure how many people would find it valuable to spend their time learning about a very nontechnical topic. To my surprise and delight, the seminar ended up being standing-room only, and I was able to field some great questions from the audience about how they could improve their selling and communication skills. In the many conversations I had with the conference attendees after my presentation, the common theme was that engineers felt they needed more soft-skills training in order to better serve their clients. The problem, however, was finding the time to do so when faced with the daily grind of design work.

Structural Engineers In a Training for Seismic Retrofits

Presenting at the NCSEA Summit, I’m the tiny person in upper left hand corner.

When I started my first job as a design engineer at a structural engineering consulting firm straight out of school, I was very focused on improving and expanding my technical expertise. Whenever possible, I would attend building-code seminars, design reviews and new product solution presentations, all in an effort to learn more about structural engineering. What I found as I progressed through my career, however, was that no matter how much I learned or how hardworking I was, it didn’t really matter if I couldn’t successfully convey my knowledge or ideas to the person who really mattered most: the client.

Contractors discussing building plans with an engineer.

Contractors discussing building plans with an engineer.

How can an engineer be most effective in explaining a proposed action or solution to a client? You have to be able to effectively sell your idea by understanding the needs of your client as well as any reasons for hesitation. The importance of effective communication and persuasion is probably intuitive to anyone who’s been on the sales side of the business, but not something that occurs naturally to data-driven folks like engineers. As a result of recent legislation in California, however, structural engineers are starting to be inundated with questions from a group of folks who have suddenly found themselves responsible for seismically upgrading their properties: apartment building owners in San Francisco and Los Angeles.

Imagine for a moment that you are a building owner who has received a soft-story retrofit notice under the City of Los Angeles’ Ordinance 183893; you have zero knowledge of structural engineering or what this term “soft-story” even means. Who will be your trusted advisor to help you sort it out? The City of Los Angeles Department of Building and Safety (LADBS) has put together a helpful mandatory ordinance website that explains the programs and also offers an FAQ for building owners that lets them know the first step in the process: hire an engineer or architect licensed in the state of California to evaluate the building.

Simpson Strong-Tie Structural Engineer Annie Kao at a jobsite.

Checking out some soft story buildings in Los Angeles. The Los Angeles Times has a great map tool.

I’ve had the opportunity to be the first point of contact for a building owner after they received a mandatory notice, because it turns out some relatives own an apartment building with soft-story tuck-under parking. Panicked by the notice, they called me looking to understand why they were being forced to retrofit a building that “never had any problems in the past.” They were worried they would lose rent money due to tenants needing to relocate, worried about how to meet the requirements of the ordinance and, most importantly, worried about how much it was going to cost them. What they really wanted was a simple, straightforward answer to their questions, and I did my best to explain the necessity behind retrofitting these vulnerable buildings and give an estimated time frame and cost that I had learned from attending the first Los Angeles Retrofit Resource Fair in April 2016. With close to 18,000 buildings in the cities of San Francisco and Los Angeles alone that have been classified as “soft-story,” this equates to quite a number of building owners who will have similar questions and be searching for answers.

To help provide an additional resource, Simpson Strong-Tie will be hosting a webinar for building owners in the Los Angeles area who have received a mandatory soft-story retrofit notice. Jeff Ellis and I will be covering “5 Steps to a Successful Retrofit” and helping to set a clear project path for building owners. The five steps that Simpson Strong-Tie will be recommending are:

  1. Understanding the Seismic Retrofit Mandate
  2. Partnering with Design Professionals
  3. Submitting Building Plans with the Right Retrofit Product Solutions
  4. Communicating with Your Building Tenants
  5. Completing Your Soft-Story Retrofit

We encourage you to invite any clients or potential clients to attend this informative webinar, which will lay the foundation for great communication between the two of you. As part of the webinar, we will be asking the building owners for their comments, questions and feedback so we can better understand what information they need to make informed decisions, and we will be sure to share these with the structural engineering community in a future post. By working together to support better communication and understanding among all stakeholders in retrofit projects, we will be well on our way to creating stronger and more resilient communities!

For additional information or articles of interest, there are several resources available:

Building Code Update: 2018 IBC to Reference ASCE 7-16

In early December, ICC posted the preliminary results of the Group B Online Governmental Consensus Vote, which included structural changes to the IBC, IEBC and IRC. ICC reports that there were more than 162,000 votes cast by eligible Voting Members during the three-week online voting period.

One subject of interest to building Designers, builders and some building-material suppliers was the disposition of a group of code changes that adopted ASCE 7-16 as the reference standard on loads for the IBC and IRC, and changed other parts of the IBC and IRC to reflect that.

The most controversial part of adopting the new ASCE 7-16 standard was its increase in roof component and cladding loads. The higher pressure coefficients in some cases raised the concern that the cost of roofing, roofing materials and roof repairs would be increased. Other items that raised some opposition were the new chapter on tsunami loads and the increase in deck and balcony live loads from 40 psf to 60 psf.

Despite these concerns, ICC members voted to approve the code change that adopted ASCE 7-16 as the reference for loads in the 2018 IBC, IRC and IEBC.

Along with that specific change, several other related changes were approved to correlate the IBC with adoption of ASCE 7-16. These included changes to Section 1604, General Design Requirements; adding in a new Section 1615 on Tsunami Design Requirements; modifications to Section 1613 so that seismic design requirements match ASCE 7-16; and deletion of Section 1609.6, Alternate All-Heights Method for wind design. On this last item, the argument was that since ASCE 7 now includes a simplified wind load design method, a competing method is not needed in the IBC.

Interestingly, a change to remove Strength Design and Allowable Stress Design load combinations from the IBC, which was approved by the IBC Structural Committee, was overturned and denied by the ICC Member voters. So those will remain in the IBC.

For the IRC, even though ASCE 7-16 will be shown as the referenced load standard, most changes to the actual code language relating to the new standard were denied. Items that were specifically denied included adoption of ASCE 7-16 wind speed maps, adoption of ASCE 7-16 roof pressure loading, and adoption of the new higher deck and balcony live loads. So the result is that the IBC and IRC will again be inconsistent with each other regarding wind design. On the other hand, the new USGS/NEHRP Seismic Design Maps were approved.

Future Code Corner articles will address other changes approved for the 2018 IBC and IRC.