What It’s Like To Be An Engineering Intern – By Robert

I worked several summer internships while in college, and as an employer I find them to be mutually beneficial. Companies are able to complete tasks they haven’t had time for, and students gain valuable work experience. I have been lucky to have two very good engineering interns this summer. In the spirit of having interns do my work for me, I thought it appropriate to have Robert write a blog post this week. Robert will be finishing up his degree in Architectural Engineering from Cal Poly San Luis Obispo this winter. Here is what Robert wrote about what it’s like to be an engineering intern:

When Paul first asked me to write a blog post, I was a bit mystified for two reasons. First because of the fact that Paul even knew what a blog was, and second, it meant summing up everything I’ve done for the past few months into approximately 400 words. I guess the best way to go about this is to describe one of the projects that covers most of the other projects I’ve been working on in detail and finish by touching on some of the more unique ones.

My initial project was a comparative analysis of the current holdown line with that of a competitor product line. This involved finding and categorizing all the different loading options for each holdown, either by looking up the values in the catalog or finding and deciphering the ICC-ES report. This project was particularly interesting because it exposed me to the world of code reports, which, other than the references in the Simpson Strong-Tie catalog, I had never seen before. Along with the code reports, I was able to explore the library of test data that is either digital or on paper. After running a few hundred bolt, screw, and nail calculations and comparing them to the test data, I was able to produce a rather larger spreadsheet that cross-listed everything I had researched.

The result of the spreadsheet was to test one of the holdowns in a specially-designed steel fixture to determine the effect of boundary conditions on test results. For this I had to spend some time in the R&D lab to learn how exactly things were tested. Up until this point I had only seen the results of the testing; now I was able to actually see how different products were tested. After spending some time in the lab and witnessing some testing, I had a better idea of how to tackle the test fixture. Once I had designed the fixture (by that I mean after 10 or so revisions), it was sent to the Stockton, Calif. branch to get built.

With the fixture designed, my next process was to set up the test reports for all the testing that needed to get done. As this was my first time through this process, I had quite an interesting time figuring out how to work the database and have it save what I input. Doing the test write-ups probably took five times as long as necessary, but now when others ask me to do test write-ups, it takes me no time at all. Hopefully the fixture will get built in time for me to see the testing.

Along with doing more test write ups, I have had the grace of helping the Marketing Department with their Product Information Management (PIM) project, which by the reactions I get from most of the engineers over here, they are very glad I am the one working on it. I have also had the unique experience of digitizing the future and current maps of how products are designed, manufactured and sold. I’ve also been put on the front lines when it comes to testing our FRP (fiber reinforced polymer) products and cleaning rust from metal samples to determine their rust rate.

To sum up everything, it is nothing like I expected but definitely an experience I’ll remember.

– Robert

What It's Like To Be An Engineering Intern – By Robert

I worked several summer internships while in college, and as an employer I find them to be mutually beneficial. Companies are able to complete tasks they haven’t had time for, and students gain valuable work experience. I have been lucky to have two very good engineering interns this summer. In the spirit of having interns do my work for me, I thought it appropriate to have Robert write a blog post this week. Robert will be finishing up his degree in Architectural Engineering from Cal Poly San Luis Obispo this winter. Here is what Robert wrote about what it’s like to be an engineering intern:
When Paul first asked me to write a blog post, I was a bit mystified for two reasons. First because of the fact that Paul even knew what a blog was, and second, it meant summing up everything I’ve done for the past few months into approximately 400 words. I guess the best way to go about this is to describe one of the projects that covers most of the other projects I’ve been working on in detail and finish by touching on some of the more unique ones.
My initial project was a comparative analysis of the current holdown line with that of a competitor product line. This involved finding and categorizing all the different loading options for each holdown, either by looking up the values in the catalog or finding and deciphering the ICC-ES report. This project was particularly interesting because it exposed me to the world of code reports, which, other than the references in the Simpson Strong-Tie catalog, I had never seen before. Along with the code reports, I was able to explore the library of test data that is either digital or on paper. After running a few hundred bolt, screw, and nail calculations and comparing them to the test data, I was able to produce a rather larger spreadsheet that cross-listed everything I had researched.
The result of the spreadsheet was to test one of the holdowns in a specially-designed steel fixture to determine the effect of boundary conditions on test results. For this I had to spend some time in the R&D lab to learn how exactly things were tested. Up until this point I had only seen the results of the testing; now I was able to actually see how different products were tested. After spending some time in the lab and witnessing some testing, I had a better idea of how to tackle the test fixture. Once I had designed the fixture (by that I mean after 10 or so revisions), it was sent to the Stockton, Calif. branch to get built.
With the fixture designed, my next process was to set up the test reports for all the testing that needed to get done. As this was my first time through this process, I had quite an interesting time figuring out how to work the database and have it save what I input. Doing the test write-ups probably took five times as long as necessary, but now when others ask me to do test write-ups, it takes me no time at all. Hopefully the fixture will get built in time for me to see the testing.
Along with doing more test write ups, I have had the grace of helping the Marketing Department with their Product Information Management (PIM) project, which by the reactions I get from most of the engineers over here, they are very glad I am the one working on it. I have also had the unique experience of digitizing the future and current maps of how products are designed, manufactured and sold. I’ve also been put on the front lines when it comes to testing our FRP (fiber reinforced polymer) products and cleaning rust from metal samples to determine their rust rate.
To sum up everything, it is nothing like I expected but definitely an experience I’ll remember.
– Robert

3, 2, 1. . .Countdown to Earthquake!

Guest blogger Jeff Ellis, engineering manager
Guest blogger Jeff Ellis, engineering manager

This week, I’d like to introduce Jeff Ellis as a guest blogger for the Structural Engineering Blog. Jeff is the Manager of Codes, Standards and Special Projects for Simpson Strong-Tie. Jeff will be posting occasionally on topics that are relevant to our work, especially related to cold-formed steel (CFS) construction. Here is Jeff’s post:

When was the last time you knew an earthquake was coming and witnessed its effects on a building without feeling any shaking yourself? Since the mid- to late ‘90’s, several uni-axial and tri-axial shake tables have been built and used to better understand whole building performance under actual earthquake ground motion in order to improve code requirements and, in some cases, develop performance-based design methods.

Performance-based design methods enable the owner to choose, and the engineer to design, for a specific type of desired building performance, such as collapse prevention or immediate occupancy following the maximum considered earthquake, rather than just following prescriptive code requirements.

For light-frame construction, Simpson Strong-Tie conducted shake table testing of our Wood Strong-Wall® Shearwall at the University of British Columbia in the late 90’s, CUREE ran shake table tests at UC San Diego and University of British Columbia in the early 2000’s, and the NEESWood project ran shake table tests at University at Buffalo in 2006 and E-Defense in Japan in 2009.

Shake table testing generally uses one or two earthquake records while the FEMA P-695 seismic force-resisting system design coefficient and factor analysis procedure requires several archetypical buildings for a given material or system type to be evaluated using 22 pre-defined earthquake ground motions. Therefore, after developing computer models that best match component and shake table testing, further analysis using additional earthquake records is performed to determine the adequacy of a seismic force-resisting system design procedure and its response modification coefficient and factors.

A few weeks ago, I attended the AISI Committee on Specification (COS) and Committee on Framing Standards (COFS) meetings held in Buffalo, New York. Committee members could watch the CFS-NEES full scale tri-axial shake table testing of a two-story cold-formed steel framed office building at the University at Buffalo Structural Engineering and Earthquake Simulation Laboratory. The University at Buffalo CFS-NEES portion of the project began in April and will go through August.

The purpose of CFS-NEES is to improve the understanding of overall system performance of CFS framed buildings in order to develop performance-based design methodology for the seismic force-resisting elements of these buildings, as well as continuing to improve the design and detailing requirements for CFS-framed seismic force-resisting systems.

The project team includes professors and students from Johns Hopkins University with principal investigator Professor Ben Schafer, Bucknell University, McGill University, and the University of North Texas as well as an engineer from Devco Engineering. The project includes a 12-person Industry Advisory Board made up of AISI representatives, design engineers, and manufacturers.

The two-story building, shown in Figure 1, is 23 feet wide by 50 feet long with a first and second story height of nine feet. It’s framed with six inch wide by 54 mil (16 ga) studs (600S162-54) at the first story and 43 mil (18 ga) studs at the second story, spaced at 16 inches on center and having bridging at midheight. The roof joists are 1200S200-54 and the floor joists are 1200S250-97 at 24 inches on center and are framed into a ledger attached to the side of the wall studs, shown in Figure 2.

CFS-NEES two-story building on University at Buffalo's shake tables.
Figure 1: CFS-NEES two-story building on University at Buffalo’s shake tables.
Interior view.
Figure 2: Interior view.

The floor and roof diaphragms and the two-story stacked CFS framed shear walls, unsymmetrically placed and located only at the building perimeter, are sheathed on their exterior with OSB structural wood sheathing, shown in Figure 3. The other non-shear walls are also sheathed on their exterior with OSB structural wood sheathing to fur them out for the application of DensGlass® fiberglass mat gypsum exterior sheathing. The interior walls and ceilings have gypsum board finishes.

Close up and corner view.
Figure 3: Close up and corner view.

Additional weight was added to the second floor and roof, shown in Figure 4, to ensure the building had a similar mass (approximately 77,500 pounds) depending on the structural sheathing and finish materials added during the various testing phases. Additional mass and framing was added to the roof to simulate a mechanical unit and framing to support it and the second floor contains two openings: a back stairway (14.5 ft. x 3 ft.) and an opening to the first floor (8 ft. x 10 ft.) that will also include a stairway. For design purposes, the project location is in Orange County in southern California at 33.8 degrees latitude and 117.86 degrees longitude.

Additional mass added to building. Image credit: Johns Hopkins.
Figure 4: Additional mass added to building. Image credit: Johns Hopkins University.

The various shake table test phases include shake table testing:

(1) with only the CFS framed roof and floor diaphragms and shear walls sheathed, as shown in Figure 5, destructively tested and removed,

Phase 1 testing with shear walls as only sheathed walls. Image credit: Johns Hopkins University.
Figure 5: Phase 1 testing with shear walls as only sheathed walls. Image credit: Johns Hopkins University.

(2a) building rebuilt same as in Phase 1,

(2b) same as 2a and with exterior non-shear walls sheathed added,

(2c) same as 2b and with the interior of the exterior walls sheathed with gypsum board added as shown in Figure 6,

Figure 6: Prepping for Phase 3 testing with interior finishes added. Image credit: Johns Hopkins University.
Figure 6: Prepping for Phase 3 testing with interior finishes added. Image credit: Johns Hopkins University.

(2d) same as 2c with foundation floor system for which to build interior walls upon, gypsum board installed on interior walls and ceilings and timber stairs added, and

(2e) same as 2d with the exterior walls sheathed with DensGlass® over the wood structural sheathing added.

The primary earthquake records for this testing are 100% of the 1994 Northridge Earthquake Canoga Park record (1.0g 0.2 second Spectral Response Acceleration)  to simulate the Design Basis Earthquake (DBE) and 100% of the Northridge Earthquake Rinaldi record (1.5g 0.2 second Spectral Response Acceleration)  to simulate the Maximum Considered Earthquake (MCE).

The purpose of the nondestructive shake table tests is to investigate the difference in building behavior with different materials and components added before it’s damaged. Phase 1 tested the building to 100% of the Canoga Park record and the building was removed and re-built for the next phases. Most of Phase 2 tests were to 44% of the Canoga Park record, as this was the strongest nondestructive testing for this record and building, but Phase 2e will be tested to 44% and 100% of Canoga Park followed by 100% of the Rinaldi earthquake record.Our group witnessed the Phase 2b testing to 44% of the Canoga Park earthquake record.

To investigate damage, the building is shaken with what’s called two sets of “white noise” tests in each of the three directions (two horizontal and vertical) prior to the primary test and then shaken again after the primary test to determine what, if any, differences occurred, such as the building period. These white noise tests are random excitations with average peak ground accelerations of 0.05g and 0.1g and are intended to excite a wide range of frequencies to characterize the complete frequency response of the structure.

For Phase 1, the building period was 0.32 seconds before the test and 0.56 seconds after and the damping was approximately 4% before and 18% after. In Phase 2, the addition of OSB furring sheathing decreased the building period from 0.32 to 0.2 seconds and building damping increased by approximately 3% in the long direction (period and damping values similar in the short direction) and the maximum story drift in Phase 1 and 2a tests was 1.9 inches from floor to floor.

In Phase 2d with the gypsum board finishes on the interior of the exterior walls and ceilings, the period decreased to 0.17 seconds and the damping increased by about 3%. Load cells were added to the shear wall hold-downs. Some hold-downs in some of the shear walls were in tension at the same time versus our typical simplified component level assumptions of a compression-tension couple.

Also visit the CFS-NEES Blog by Kara Peterman, Johns Hopkins University graduate student for more information on the project.

– Jeff

2012 Autodesk University

Autodesk University is an annual conference focused on keeping the design community up to date on the latest innovations, trends and technologies in design, drafting and visualization. Last year, Autodesk University was held in Las Vegas the week after Thanksgiving. Sadly, events always seem to conspire to prevent me from going to Vegas, but Simpson Strong-Tie was well represented by Frank Ding, our Engineering Analysis & Technical Computing Manager.

Frank received his Bachelors and Masters degrees in Manufacturing Engineering from Beijing University of Aeronautics and Astronautics, and has a Ph.D in Mechanical Engineering from Washington State University. Frank joined Simpson Strong-Tie in 2004 to head up our Finite Element Modeling efforts. Frank now manages all of our technical computing efforts, which includes keeping up with the latest developments that can assist us in our R&D efforts. So with introductions complete, I’ll let Frank tell you about his Autodesk University experience:

It was an exciting time attending my first Autodesk University in 2012. I have been to so many technical conferences during my professional career, but this one was quite different in scale, and the sheer size of it just blew me away. There were more than 8,000 attendees from 102 countries, more than 750 classes offered, and 163 exhibitors. I was impressed by the organization of such a large event, along with the online and mobile apps provided to help attendees manage their conference schedules.

My past impression of Autodesk was only limited to AutoCAD for 2D modeling. Now it has more than 40 SKU’s of different design software for use in the architecture, engineering, construction, manufacturing, media and entertainment industries.

Highlights of the conference, from my perspective, include:

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Is Your New Hire Ready For The Working World?

Cal Poly students attend a Simpson Strong-Tie workshop (May 2012)

It’s that time of year again: newly graduated college students are entering the workforce.  For the student, it’s an anxious time. They are often wondering how and if four plus years of college has effectively prepared them for the real working world. For the potential employer, it can be a gamble. They have decided to take a chance on someone who likely does not have any professional work experience, but expect production from day one. On a recent visit to Cal Poly San Luis Obispo, my colleague Scott Fischer got a firsthand view of what students are doing to prepare for a career.

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Code Development: The ASTM Process

I spent a few days last week traveling to attend the Spring ASTM International meetings held in Phoenix, AZ. When I was working as a building designer, I always used ASTM standards in my project specifications or testing and special inspection requirements on a job. But I did not know how these ASTM standards were developed, nor did I know that I could participate in the process.

ASTM standards are voluntary in the sense that ASTM does not require their use. However, since ASTM standards are referenced in building codes and design standards that are adopted by states and local jurisdictions, compliance with those standards is required. So it might be useful for structural engineers to know a little bit about how these standards are created.

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