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Jan. 21st, 2008 Edition - We're Back!!

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Shake Table Tests Prove Structures Can Be Seismically Sound With Less Steel Than Called for by Current California Code - San Diego, View CBS coverage of testing in Real Player  University of California, San Diego (UCSD) structural engineers have announced that a violent simulated reproduction of the Northridge earthquake shook a seven-story structure at the UCSD Jacobs School of Engineering's Englekirk Structural Engineering Center, and resulted in only minor cosmetic damage to the building.  The experiment, (Click to view Video 1 from angle in photo above) along with earlier shakes, was conducted to test a revolutionary new theory that mid-rise concrete apartment, condominium and hotel structures can be built to survive powerful earthquakes using less steel reinforcement than currently required by California building codes.

"Many people don't realize that excessive building strength can actually promote poor structural performance and non-structural damage during an earthquake," said Robert Englekirk, founder of the Englekirk Companies and a co-principal investigator of the project. "The structural engineering community wants to develop regional design procedures that allow for the development of more suitable buildings in Southern California."  UCSD structural engineers said the building held up as well as the theory. 

The test (click to view Video 2 of the southeast corner of the structure, links to more videos can be found at the bottom of the middle column) was conducted under tight safety precautions with the powerful mechanical jolts delivered by a 25 ft. by 40 ft. shake table. The experiment duplicated ground motions from the Jan. 17, 1994, Northridge earthquake that were recorded at the Olive View Hospital in Sylmar, CA.  The 275-ton, 65-foot-tall building was also tested on Nov. 22, 2005, with ground motions that were recorded during the Northridge earthquake farther from the epicenter, at a seven-story hotel in Van Nuys, CA. The November, 2005 test produced horizontal accelerations that were 30 percent of the force of gravity, and the Jan. 14 test simulated the earthquake closer to its epicenter, with horizontal accelerations of 82 percent of gravity.

"What we found is fairly simple; if we use an intelligent design strategy that reduces the demands required by the current California building standards, and use about half the reinforcing steel that's required, mid-rise buildings will survive powerful earthquakes with only minor damage," said Jose Restrepo, professor of structural engineering at the UCSD Jacobs School of Engineering Department of Structural Engineering and co-principal investigator of the project.  Prof. Restrepo likened the design to that of a car, where upon impact, a large amount of the force is dissipated at the bumper, prior to spreading through the car to the passenger area.  So to in this design, the intent was to have the brunt of the impact absorbed in an energy absorbing  “plastic hinge” located at the ground floor, causing a dissipation of the earthquake forces prior to their spreading throughout the building.  Restrepo said the performance of the seven-story building was even better than the sponsors of the project had expected. "The professional engineers we have talked to were thrilled," said Restrepo.

“I can’t tell you how satisfying it is to see the BauGrid Welded Reinforcement Grids (WRG) withstand such tremendous large tension and compression forces,” said Hanns U. Baumann, S.E., president of BauTech, Inc., which donated the WRG that were used as the confinement reinforcement in the walls of the 7-story test structure.  “This design is one that Bob Englekirk has espoused for some time, and I’m glad to see that Prof. Restrepo’s test program has done such an excellent job of showing that he was absolutely right.” said Baumann.   Baumann added that “Because of public safety concerns, it is quite important that design engineers understand that the WRG used in this structure is not the same as the much weaker Welded Wire Reinforcement (WWR).  WRG is manufactured with high strength welds at every location where the steel rods intersect, which provides the unique and valuable inter-cell confinement that was exhibited during the test.”

Restrepo said the seven-story building may be put through additional tests to provide further scientific confirmation that less reinforcing steel than currently required could improve the performance of mid-rise concrete buildings in densely populated and seismically active regions in California.

Sixty people were killed and 7,000 injured during the Northridge earthquake which left 20,000 homeless, and damaged more than 40,000 buildings in Los Angeles, Ventura, Orange, and San Bernardino Counties. The death toll and roughly $40 billion in property damage prompted professional structural engineers to call for more scientific testing of mid-rise residential buildings.

When asked how soon new design procedures such as this could be incorporated into Southern California buildings, in that implementation of new ideas into building codes is a process that is notoriously slow moving, Englekirk stated that the current code already allows use of this “performance-based” design.  “The code allows engineers two ways to design structures.  There are prescriptive designs, as spelled out in the codes, and there are performance-based designs, where through the use of testing and proven scientific methods, it is shown that a design is safe.”

Continued next column

Yes, we're back, and we promise not to go away for such a long time again.  We will be updating on a regular basis again, and we hope that you'll join us as we try to make information about construction trends and innovation more available on the net.  Thanks to those of you who subscribed to our newsletter, even during the dormant period.  We'll be contacting you soon with lots of fresh construction news and innovations.  Do you have news and information you'd like to share?  Builders, academics, designers and contractors, what are you doing that's new and different?  Would it help the construction industry if information about your new research, products, or building methods were more widely distributed?  Let us help you spread the word!!  Tell us about it!!


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Shake Table Test, Continued

Full-scale tests of such large buildings have previously not been possible because of weight, space, and technical limitations of smaller indoor shake tables. UCSD's shake table can actually support a building roughly 10 times heavier than the seven-story structure it currently holds.

The $9 million shake table at the Jacobs School's Englekirk Center is one of 15 earthquake testing facilities in the National Science Foundation's Network for Earthquake Engineering Simulation. The UCSD-NEES shake table, the largest in the U.S. and the only outdoor shake table in the world, is ideally suited for testing tall, full-scale buildings.  Click here to take an animated tour of the facility.

Construction of the seven-story test building was led by Highrise Concrete Systems, Inc. of Dallas, TX, a company which specializes in the construction of multi-story concrete buildings using the latest formwork technology.  Additional financial support donated equipment and labor was provided by Tech, Inc.; Dywidag Systems International, USA;, Inc. (DSI); HILTI; Associated Ready Mix; California Field Ironworkers; Cemex: Concrete Steel Reinforcing Institute (CRSI); Douglas E. Barnhart, Inc.; Englekirk & Sabol, Inc.; Fontana, Grace, Hanson Aggregates; Morley Builders; Pacific Southwest Structures; Schuff Steel-Pacific Inc.; Southern California Ready Mix Concrete Association; the Portland Cement Association(PCA); and Carpenters/Contractors Cooperation Committee, a nonprofit labor and management group. 

The Englekirk Structural Engineering Center, part of UCSD's renowned Powell Structural Research Laboratories, is named in recognition of Robert and Natalie Englekirk's support of structural engineering research and education at UCSD Jacobs School of Engineering Department of Structural Engineering. Construction of the Englekirk Center and the earthquake research program there are supported by the Englekirk Center Industry Advisory Board, a group of 43 structural engineering firms and associations in Southern California. Patron members include Carpenters/Contractors Cooperation Committee, Englekirk Systems Development, Inc., and Highrise Concrete Systems, Inc. Other partners include: American Segmental Bridge Institute; Anderson Drilling; Baumann Engineering; Brandow & Johnston Associates; Burkett and Wong Engineers; Charles Pankow Builders, Ltd.; Clark Pacific; Douglas E. Barnhart, Inc.; Dywidag Systems International, USA, Inc. (DSI); Englekirk and Sabol Consulting Structural Engineers, Inc.; EsGil Corporation; GEOCON; Gordon Forward; HILTI; Hope Engineering, Inc.; John A. Martin and Associates; Josephson Werdowatz & Associates Incorporated; JVI, Inc.; KPFF Consulting Engineers; Matt Construction Corporation; Morley Builders; Nabih Youssef and Associates; Oak Creek Energy Systems; Occidental Petroleum Corporation; Pacific Southwest Structures; PCL Construction Services, Inc.; Portland Cement Association; Precast/Prestressed Concrete Manufacturers Association of California (PCMAC); Saiful/Bouquet Consulting Structural Engineers, Inc.; Schuff Steel-Pacific, Inc.; Structural Engineering Association of Southern California (SEAOSC); Simon Wong Engineering, Simpson Manufacturing Co., Inc.; Smith-Emery Company; Stedman & Dyson Structural Engineers; The Eli & Edythe L. Broad Foundation; Twining Laboratories; UC San Diego Design and Construction; Verco Manufacturing Co.; Weidlinger Associates, Inc.; and the Structural Engineering Association of San Diego (SEAOSD).

View CBS coverage of testing in Real Player

Video of base cracking

Video of bottom cracking

Video of corner cracking

Video of first floor movement

Video of desk on first floor

Video of perpendicular view of testing (Video 1, above left)

Video of southeast view of testing (Video 2, above left)

World of Concrete Underway  by Bill Coburn

Jan. 21, 2008

The World of Concrete kicked off on Sunday with a tour of the Hoover Dam bypass, and today dozens of seminars were conducted with the intent of educating attendees on the latest news in concrete construction and technology.  The World of Concrete uses more than 900,000 square feet to inform its attendees about 1600 exhibiting companies or organizations from 22 nations.  The World of Concrete is being held in Las Vegas, at the Las Vegas Convention Center, and while figures are not yet available on the number of people coming to this year's event, I'm told that in excess of 91,000 people were registered for last year's event.  I am on-site in Vegas, and will be updating the website with reports over the next few days.  If you can fit it into your schedule, drop what you're doing and head to Vegas, this is by far the most comprehensive look at concrete anywhere in the world today. In addition to the training seminars and trade exhibits, there are ACI certification courses and trade demonstrations, including decorative concrete contests, bricklaying contests, and trucking/equipment driving skill demonstrations.  If you can't make it this year, plan ahead.   Next year's event is scheduled for Feb. 2nd through 6, 2009.


San Francisco’s 590-ft Skyscraper Lifts Seismic Design's Stature

 Performance-based concrete job breaks per-floor speed record on West Coast


By Nadine M. Post for ENR in San Francisco

Structural engineer Ron Klemencic had extra reasons for gratitude during the 2005 Thanksgiving season. After hitting his head against the wall on and off for more than three  years, he finally received stamps of approval for the first two performance-based seismic design high-rises in earthquake prone San Francisco. PSD can cost less, improve design and ease construction.

Word about the 38- and 43-story Infinity towers came the last week of November, followed by news about the 64-story One Rincon Hill (ORH) in early December. “I was elated both times,” says Klemencic, president of Magnusson Klemencic Associates, Seattle. “It was two years of blood sweat and tears on [the Infinity] before we even initiated Rincon Hill.” That review took a year, twice the norm for San Francisco towers.

The city’s approval marked the beginning of the end of a logjam in big California cities for performance seismic design (PSD) of buildings taller than 240 ft. “People are going to be doing this left-handed at 100 mph in five years thanks to Ron...,” predicts one prominent San Francisco architect who declines to be identified...Read the whole story


Former ACI Director Joins American Society of Concrete Contractors

Jan. 2, 2008

Ward R. Malisch has joined the American Society of Concrete Contractors (ASCC) as technical director.  He was senior managing director of the American Concrete Institute (ACI), a position from which he recently retired. 

Malisch previously was editor of Concrete Construction magazine for nearly 15 years, the director of construction information services for the Portland Cement Association, and ACI's managing director of enginering.  He taught at several universities for nearly 20 years.

Malisch received his B.S., M.S., and Ph.D. degrees in civil engineering from the University of Illinois.

In addition to his other duties at ACI, Malisch answered concrete contractors' questions via the ASCC technical hotline, and wrote the organization's Troubleshooting Newsletter.  He has been a member of the ASCC Board of Directors since 2001 and is a former chair of the ASCC Education and Training Committee.  He assisted n producing ASCC's 26 Position Statements that offer practical answers to situations commonly faced by concrete contractors.

As technical director, Malisch will continue to answer the hotline and produce the Troubleshooting Newsletter.  His duties will also include reviewing construction related ACI documents, writing technical articles and papers, coordinating research projects, providing contractor input on technical matters to other organizations, and developing programs for the technical education of contractors.

The ASCC is a non-profit organization dedicated to enhancing the capabilities of those who build with concrete, and to providing them a unified voice in the construction industry.  Members include concrete contracting firms, manufacturers, suppliers and others interested in the concrete industry, such as architects, specifiers and distributors.  There are approximately 575 member companies in the United States and five foreign countries.  For more information on the ASCC, visit the website at or call (314) 962-0210.


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