Lafarge North America recently made history in Calgary, Alberta, with the Glenmore/Legsby footbridge.  Weighing 100 tonnes and completing a span of 53 meters, the Glenmore/Legsby project has the distinction of being the largest ultra-high performance pour completed in the world.  This is the second footbridge made of Lafarge’s Ductal® in North America.  The six-stage capital project included a road widening, a bridge replacement, a new pedestrian overpass, and the creation of a pedestrian/bicycle pathway.

The Glenmore/Legsby pedestrian overpass crosses eight lanes with a single span, 53-meter post-tensioned bridge. It consists of two cantilevered high-performance concrete abutments and a drop-in T-Section Ductal girder with an arch. The girder measures 33.6 meters long, 3.6 meters wide and is only 1.1 meters deep at mid-span. The beam was post-tensioned with two bundles of strands and glass fiber reinforced plastic bars (GFRP) as an extra safety precaution.

The use of Ductal precast enabled an installation that limited traffic disruption on Glenmore, the second busiest artery in Calgary. Lafarge produced the footbridge component in-house and was able to erect the superstructure between midnight and 7:00 a.m. on a Saturday.

In addition, Ductal was used for a public art project by Violet Costello and Bob Thomasson. Colorful fish measuring 15 feet in length and five feet in height adorn a precast high-performance concrete retaining wall that lines the Glenmore corridor.

Cohos Evamy designed the innovative footbridge that officially opened June 9, 2007.
Photo courtesy of City of Calgary

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PCA’s spring forecast had anticipated a 20.5 percent decline from 2006 levels resulting in a 4.5 percent drag.  Single-family housing accounted for nearly 25 percent of U.S. cement consumption in 2005.

High inventory levels are playing an important role in the slow recovery of the single-family housing market.  Sullivan estimates that the current inventory of 4.1 million homes represents an eight-month supply, compared to the desired five-month supply.  Because home sales are diminishing, the correction process most likely will continue until the fourth quarter of 2008.
Contact Ed Sullivan

PCA recognized by American Red Cross
The American Red Cross of Greater Chicago honored PCA with the Stuart Wesbury Award for Community Partnership on June 19 its annual Board meeting.  PCA was lauded for their support as a founding member of the Safe Home Illinois initiative.

Safe Home Illinois, jointly sponsored by the Red Cross and the Illinois Emergency Management Agency, educates government officials, industry professionals and the public on building products and techniques that can mitigate tornado and wind storm damage.  Established in early 2006, the Safe Home Illinois partners have held a number of mitigation seminars and events in the Chicago area, in addition to recently constructing a precast concrete Fortified…for safer living® home in the suburb of Aurora, Ill.

PCA has been an active participant of the program including instructing at several seminars. Other Safe Home Illinois partners receiving a Wesbury Award were Simpson Strong-Tie and PCI members Dukane Precast and Pre-Stress Engineering Corporation. 

After the meeting, the Red Cross Board members witnessed a visually impressive “tornado cannon” demonstration in an adjacent parking lot, that illustrated the impact resistance of concrete wall systems as compared to traditional wood-framed construction.  The Chicago Fox News affiliate was also on hand to cover the event.
For more information on the Safe Home Illinois program, visit www.safehomeillinois.org

Fall Committee Meetings Slated for September
PCA's Fall Committee Meetings are scheduled for September 10-12, 2007, at Chicago's InterContinental Hotel. Most committees of the Market Promotion Council and Research and Technical Council will meet.

The cutoff for hotel reservations is August 13; program registrations are due by August 31.
Contact Jan Farnsworth
Visit www.cement.org for a preliminary schedule and online registration

First Comprehensive Set of Model Code Changes Adopted Based on NIST WTC Study Recommendations
Several model code changes consistent with the NIST WTC investigation recommendations will be incorporated into the 2007 supplement to the International Code Council’s (ICC) International Building Code (IBC).  

Model code changes of interest to the cement and concrete industries that are now required by the IBC—including those approved at the ICC final action hearings in Rochester, N.Y., during May 21-26, 2007—are:

• An additional exit stairway for buildings more than 420 feet in height.
• A minimum of one fire service access elevator for buildings more than 120 feet in height.
• Increased bond strength for fireproofing (nearly three times greater than currently required for buildings 75-420 feet in height and seven times greater for buildings more than 420 feet in height).
• Field installation requirements for fireproofing to ensure that:
  • installation complies with the manufacturer's instructions;
  • the substrates (surfaces being fireproofed) are clean and free of any condition that prevents adhesion;
  • testing is conducted to demonstrate that required adhesion is maintained for primed, painted or encapsulated steel surfaces; and
  • the finished condition of the installed fireproofing, upon complete drying or curing, does not exhibit cracks, voids, spalls, delamination or any exposure of the substrate.
• Special field inspections of fireproofing.
• Increasing by one hour the fire-resistance rating of structural components and assemblies in buildings 420 feet and higher.
• Explicit adoption of the "structural frame" approach to fire resistance ratings that requires all members of the primary structural frame to have the higher fire resistance rating commonly required for columns.

Two more model code changes will be considered for the next edition of the IBC in 2009.   If adopted, the first new model code provision would recommend that structures be designed to mitigate disproportionate progressive collapse and ensure, for the first time, minimum structural integrity and robustness requirements for structures as complete systems.

The second proposed code change would require the use of a nationally accepted standard for conducting wind tunnel tests routinely used for determining wind loads in the design of tall buildings.  A nationally accepted standard for estimating wind loads and their effects on tall buildings based on wind tunnel testing remains to be developed.

Additionally, a model code change proposal that was not accepted into the IBC, but is being revised using feedback from ICC members, addresses enhancing the functional integrity and survivability of exit stairway wall enclosures for buildings greater than 420 feet in height.  It would require wall surfaces to possess a minimum level of structural robustness through an ability to withstand a sudden increase in pressure.
Contact David Bilow
For information on PCA Code activities, contact Steve Szoke
For more information on the NIST WTC recommendations, visit http://wtc.nist.gov.

Holcim Awards Competition Now Open
The second Holcim Awards competition to promote sustainable construction worldwide is now open. The Holcim Awards are an international competition for projects that embody approaches to meet the present-day needs for housing and infrastructure without compromising the ability of future generations to meet their own needs in times to come.

Entries in the competition can be submitted until February 29, 2008. The prize money for the five regional competitions and the global awards totals $2 million.

The Awards are open to anyone involved with projects in the area of sustainable construction – architects, planners, engineers, or project owners. All building projects are eligible for the competition if construction had not started before June 1 of this year. The first phase of the competition will select regional winners in 2008 that will automatically qualify for the global competition to be held in 2009.

In addition to construction projects at an advanced stage of design, the Awards competition seeks visions and ideas at a conceptual level. This special category is open for professionals younger than 35 years of age.

Notable Comments

"Hurdle is improving communications on the design team between M&E, structural engineer, and architects. Synergy among the design team members can identify excellent opportunities for sustainable design development, application, and implementation for buildings."

"Passive designs will be one element of a many faceted approach to energy conservation."

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