Archive for July 2011
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Steel Shots: Exploring Staggered Trusses
Posted by Tasha Weiss on July 29, 2011 at 9:30 AM.
You may have heard of a staggered truss system - it was developed in the 1960s at MIT and has been used in many multi-story residential projects nationwide - but can you define it? Shown in the above photo, the system consists of story-high trusses that span the entire width of the building. The trusses alternate from floor to floor with the long axis of one truss mid-span between the trusses on the floors immediately above and below. This system has proved to be an efficient structural solution that resists both gravity and lateral loads in the direction of the trusses. Photo: John Cross.
Nearly 50 architects, engineers, contractors, and other construction professionals discovered the steel staggered truss system up close during a recent seminar and site tour of The Ohio State University South High-Rise Residence Halls project in Columbus. You can view the presentation files and more photos from the event on AISC’s website at www.aisc.org/osu.
The system works in harmony with hollow-core precast concrete floor planks, allowing for the desired low floor-to-floor heights. The precast plank spans from the top chord of one truss to the bottom chord of the next, achieving large column free areas on each floor and provides a smooth floor and ceiling.
You’ll notice in the above photo that the only columns are found on the exterior of the structure and the entire ground level can be completely column-free, allowing for tremendous flexibility in room layout and architectural design elements. And fewer columns mean fewer foundations, resulting in reduced foundation costs and schedule.
Additionally, the construction schedule can often be compressed by using staggered truss. Because the steel trusses and precast planks are both off-site fabricated, there are fewer pieces to erect on-site, and the system goes up relatively fast. The dry system also allows for winter construction.
For additional information, see AISC’s Steel Design Guide No. 14, Staggered Truss Framing Systems. It is available as a free download for AISC members and for purchase by non-members at www.aisc.org/dg.
SteelDay Student Photo Contest
Posted by Tasha Weiss on July 28, 2011 at 9:11 AM.
Say “SteelDay!” (Click) In conjunction with this year’s SteelDay, AISC is again sponsoring a Student Photo Contest as one way to involve students in the industry’s largest educational and networking event. The contest is designed for students to capture photos that best pictorially celebrate the visual experience of steel and is open to any student currently enrolled in a graduate or undergraduate program at an accredited U.S. college or university.
To be eligible, students must submit a photograph and a completed application form, including a brief description of the photograph. The description can include information such as details regarding the photo subject, interesting elements in the photo and/or how this photo celebrates the visual experience of steel. There is no fee to enter, and the number of complete submissions per student is not limited.
Deadline for entries is Saturday, September 17, 2011. The winner will be announced on SteelDay (September 23) and the winning photos will be published in MSC. Check back here for a news post with the winning photos after they’re announced.
For more information and to download the full rules and application form, visit the AISC website at www.aisc.org/photocontest, where you can also view last year’s winning photos.
Supporting Domestic Steel and Domestic Jobs
Posted by Tasha Weiss on July 27, 2011 at 3:16 PM.
The National Steel Bridge Alliance recently issued detailed statements outlining its objections to a New York Times article, “Bridge Comes to San Francisco With A Made-In-China Label,” and related projects that plan to use federally provided funding to purchase foreign steel and off-shore fabrication. NSBA and AISC encourage the steel community to take action on this issue and contact their local representatives at www.aisc.org/action.
Read NSBA’s Letter to the Editor submission in response to the article, in the July edition of NSBA’s newsletter, here.
NSBA also recently issued a press release on Alaska Railroad Corporation’s (ARRC) similar abuse of federal funds for the $190 million Tanana River crossing project, which you can access here.
NSBA’s public statements have garnered significant feedback from those in the structural design and construction industry, supporting the organization’s efforts to use U.S. steel and labor on domestic projects.
For example, NSBA recently received a letter from Roumen V. Mladjov, S.E., P.E., Louie International. Here are some excerpts from his letter [Note: The letter expresses the views of the author and are not the words of NSBA]:
…The decision to contract the suspension part of the new East Span of the Bay Bridge to China was wrong and cannot be excused. There is a passage in the article that deserves more attention – ‘“I do not think the U.S. fabrication industry could put a project like this together,’ Brian A. Petersen, project director for American Bridge/Fluor Enterprises.” I do not know if Mr. Petersen has made this statement, but when The New York Times publishes it, it is a very big offense for the American steel industry and for all our great predecessors in bridge design and construction.
The New East Span Bay Bridge (San Francisco-Oakland) is one of the worst projects in the country. It is not only the most expensive bridge in the world (the March 2011 report estimates the cost will reach $6.45 B), but is also one with the slowest construction. The current estimate is for completion at the end of 2013, or 12 years of construction.
In 1936 American Bridge Company built the original Bay Bridge (suspension spans, tunnel and east span) for three years and seven months, and today, in 2011, Caltrans needs 12 years to build one half of the easier part of the same bridge with all the benefits of the most advanced construction technology.
One of the secondary, but very dangerous, results from the Bay Bridge case is that engineers and builders are getting disinterested in working on bridges. Not only has a huge amount of money, time, human and equipment involvement been used for this bridge, but we have lost a golden opportunity to demonstrate to ourselves and to the world engineering community that Americans still are able and can build great bridges…
New Edition of Guide Spec for HPS Bridges
Posted by Tasha Weiss on July 27, 2011 at 9:45 AM.
The Steel Market Development Institute (SMDI) has published an update to the Guide Specification for Highway Bridge Fabrication with High Performance Steel. This third edition replaces the previous edition, which was published in 2003, and provides bridge owners, designers and fabricators with the latest recommended methodology to fabricate and weld structures using ASTM A709 or AASHTO M270, Grade HPS 70W (HPS 485W) steel.
“This new edition of the Guide Specification is based on continued research with high performance steel (HPS) fabrication and welding practices conducted under a cooperative agreement sponsored by the Federal Highway Administration, the U.S. Navy, and SMDI,” said Alex Wilson, chairman of SMDI’s Steel Bridge Task Force and manager, customer technical service at ArcelorMittal USA LLC.
The third edition of the Guide Specification for Highway Bridge Fabrication with High Performance Steel is available as a free download from the SMDI website at http://bit.ly/qqdgnc.
Equipment Leasing Rises Again
Posted by Tasha Weiss on July 26, 2011 at 8:49 AM.
The Equipment Leasing and Finance Association’s (ELFA) Monthly Leasing and Finance Index (MLFI-25), released today, shows overall new business volume for June was $7.3 billion, up 33% from volume of $5.5 billion in the same period in 2010. Compared with May volume, June volume increased by 30%. Year to date, new business volume is up 28.5% over last year.
The MLFI-25 reports economic activity for the $521 billion equipment finance sector and reflects the volume of commercial equipment financed in the U.S. Based on data reported by participating ELFA member equipment finance companies, the MLFI-25 is a barometer of the trends in U.S. capital equipment investment. Five components are included in the survey: new business volume (originations), aging of receivables, charge-offs, credit approval ratios, (approved vs. submitted) and headcount for the equipment finance business.
ELFA says the report complements the durable goods report and other economic indexes, including the Institute for Supply Management Index, which reports economic activity in the manufacturing sector. Together with the MLFI-25 these reports provide a complete view of the status of productive assets in the U.S. economy, specifically, equipment produced, acquired and financed.
To read the full ELFA press release, click here.
Reminder: Higgins Lectureship Nominations Due August 1
Posted by Tasha Weiss on July 25, 2011 at 8:40 AM.
Remember to submit your T.R. Higgins Lectureship Award nominations in the mail by the end of the week! They must be received by Monday, August 1. Each year the T.R. Higgins Lectureship Award recognizes an outstanding lecturer and author whose technical paper or papers, published during the eligibility period, are considered an outstanding contribution to the engineering literature on fabricated structural steel.
AISC encourages anyone involved with steel construction to submit nominations. Winners receive a framed certificate, which is presented at NASCC: The Steel Conference, and a $10,000 cash award.
For more detailed information from the AISC website, click here.
Hanging (From) Steel
Posted by Tom Klemens on July 22, 2011 at 9:18 AM.
The Flying Dutchman attraction at the Mall of America offers an excellent view from 56 ft above the main floor of the Nickelodeon Universe theme park.
If you happen to be including a visit to the Mall of America near Minneapolis in your summer (or future) travel plans, be sure to set aside a few minutes to tackle the Flying Dutchman, especially if the kids are with you. Tucked in the corner of the mall’s enclosed theme park, Nickelodeon Universe, this climbing adventure experience gives you a first-hand look at what it’s like to be tied off to steel framing six stories up.
For a very reasonable fee (about $6, if that’s all you choose to do) participants don a full-body harness and climb to the top of the steel framework. Then, fully tethered, they go back and forth across cables, beams and other tenuous crossings as they work their way back down to terra firma.
Although this attraction has a pirate ship theme — hence its name, the Flying Dutchman — it provides a good approximation of what it’s like to navigate steel framework before the rest of the structure is in place. It claims to be the tallest Sky Trail ropes course in the world, challenging guests to climb 56 feet above Nickelodeon Universe.
Incidentally, the track for the sliding tether anchorage makes for some pretty fancy connections. Click the photo to see one close up.
Engineering Journal Q1 Now Online
Posted by Tom Klemens on July 21, 2011 at 1:11 PM.
AISC members are reminded that the First Quarter 2011 issue of Engineering Journal is now available online in digital edition format. Members can view, print, and share the current issue online by clicking here.
Papers in Engineering Journal Q1 include:
- “Analysis and Design of Steel Slit Panel Frames (SSPFs) for Seismic Areas,” by Gustavo Cortes and Judy Liu.
- “A Simple Stepped-Column Buckling Model and Computer Algorithm,” by Jorge Vasquez and Rafael Riddell.
- “Fillet Weld Design for Rectangular HSS Connections,” by Jeffrey A. Packer and Min Sun.
- “Plastic Moment of Intermediate Horizontal Boundary Elements of Steel Plate Shear Walls,” by Bing Qu and Michel Bruneau.
The complete collection of Engineering Journal articles is searchable at www.aisc.org/ej. Downloads of current and past articles in PDF format are free to AISC members and ePubs subscribers; just make sure you are logged into the AISC website before searching. Non-members will be directed to the AISC Bookstore to purchase article downloads.
Online Voting Open for 2011 Tekla BIM Awards
Posted by Tasha Weiss on July 20, 2011 at 11:09 AM.
Vote for your favorite 3D model projects around the country! Online voting for this year’s Tekla North American BIM Awards is open to the public until Thursday, July 28. The awards program is divided into three categories: BIM, steel, and concrete. See and vote for projects by clicking on the Tekla BIM Awards website here.
Project entries vary from airports to concert halls, sculptures, stadiums and more. Your votes will decide the finalists, and the winners will be chosen by a jury of leading BIM experts inside and outside Tekla. The winners will be announced and awarded on Aug 12 at the Tekla North American User Meeting 2011 in Las Vegas. All winners in the North American program will be automatically entered into the Tekla Global BIM Awards competition.
Complete program information is available on the Tekla website by clicking here.
To view the 2010 entries, including winners, start here.
Free Electronic Resource Available on Reducing Risks of Earthquake Damage
Posted by Tasha Weiss on July 19, 2011 at 10:09 AM.
The Applied Technology Council (ATC) and the Federal Emergency Management Agency (FEMA) introduce a free electronic document for use by non-engineers titled, “FEMA E-74, Reducing the Risks of Nonstructural Earthquake Damage; A Practical Guide, Fourth Edition.”
This guide explains the sources of earthquake damage that can occur in nonstructural components and provides information on effective methods for reducing risk associated with nonstructural earthquake damage. It is a valuable resource particularly for building owners, facility managers, maintenance personnel, store or office managers, corporate or agency department heads, and homeowners.
The electronic document and a table of contents can be found on FEMA’s website, here. Download the PDF from the FEMA Library.
AISC recently released a free electronic document, “Facts for Steel Buildings Number 3: Earthquakes and Seismic Design,” the newest installment in the Facts series. Download the PDF from AISC’s website. For more information on this publication visit our previous news post, here.