The International Information Center for Structural Engineers

Wednesday, 30 July 2014 10:52

UPDATE: Bertha’s Repair Further Delayed

Repairing the tunnel-boring Bertha hit more delays this past week when it was announced the deep access pit that is being built to reach the front side of Bertha would be delayed by a month. Crews need more time to grind and chisel through concrete so the 120-foot deep vault in front of Bertha will be completed in August instead of July as originally planned. Chris Dixon, project director for Seattle Tunnel Partners, believes Bertha will still be fully repaired by March because the repairs had a two-month cushion added to the schedule. While Seattle Tunnel Partners is confident that the machine will be ready to complete the remaining 8,200 feet of tunneling needed for the Alaska Way Viaduct Replacement Tunnel project on time, Washington Department of Transportation is not as optimistic.

Monday, 28 July 2014 10:44

I-35W Bridge Beginning to Age

Seven years after the Minneapolis I-35W bridge collapse occurred, the replacement bridge is starting to age. Bridge inspectors recently found cracks in concrete girders, a clogged drainage hole, and rust above the bridge’s piers. The new I-35W bridge over the Mississippi River was built in 2008 after the after the old bridge fell into the river on August 1, 2007. The collapse killed 13 people and injured 145. Improperly designed gusset plates were ultimately determined to be the reason for the collapse. Federal regulators also discovered that the gusset plates were not given proper attention during inspections. 

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Thursday, 24 July 2014 10:46

South Korea’s Tallest Skyscraper Opens

South Korea’s tallest building, the Northeast Asia Trade Tower (NEATT), has finally opened after being completed nearly three years ago. American firm Kohn Pedersen and Fox designed the tower and New York developer Gale International worked with South Korean steel company Posco Engineering and Construction to build the structure. The skyscraper is part of the $35 billion Songdo International Business District that was built from scratch starting eight years ago. The 1000-foot, $614 million skyscraper was completed in 2011, but its interior was not finished due to financial difficulties during the recession. After a three year delay, the NEATT is finally opening its doors to the public.

Workers began drilling piles for the Tappan Zee Bridge in March. Since then, equipment has slowly accumulated on the Hudson River in New York to help build the bridge. Perhaps the most impressive piece of equipment arrived last week though when a barge-mounted concrete production factory arrived on site. The barge is one of a pair that will make 300,000 cubic yards of concrete for the new bridge span. The two barges are expected to reduce costs throughout the length of the project and also will likely make the project run smoother as the concrete will not need to be transported to the site. Workers will not have to worry about the concrete getting delayed due to traffic or road hazards. Had the decision been made to make the bridge’s concrete at a regular production factory, the Tappan Zee bridge project would have added 30,000 trucks to the road to transport the concrete throughout the duration of the project. The 60 foot by 200 foot barge is capable of producing 125 cubic yards of concrete per hour and can test the concrete in a laboratory located on the barge.

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The Kentucky Department of Transportation has been trying to build a new bridge on I-69 over the Ohio River for many years. The bridge would link Henderson, Kentucky and Evansville, Indiana. When the bridge was first being discussed a decade ago, a $1.4 billion price tag was the popular estimate for the bridge’s cost. This cost estimate proved prohibitive for any discussion of building the bridge as taxpayers felt it was going to be far too expensive to complete the project.  Now, however, a Henderson-Evansville I-69 advocacy group is presenting a modified vision of the project that would lower the cost to $800 million.

Researchers from the Fraunhofer Institute for Non-Destructive Testing IZFP in Saarbrucken, Germany have been working on building robots that can inspect buildings for damage. The current prototype, which made its first inspection in 2011, significantly reduces the amount of time needed to inspect, compared to having a human carry out the inspection, and also does not interfere with the usage of the building. Germany has put a strong focus over the past few years on inspecting many of the country’s concrete buildings. Most of these structures were built in the years following World War II and have begun to deteriorate over the last 60 years due to heavy loading and inclement weather. The current standard of using test engineers to inspect buildings with their naked eye is both time consuming and not completely accurate. It can also require special equipment such as cranes and helicopters to inspect parts of structures that are difficult to reach.

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The first of several claims related to the Panama Canal’s $1.6 billion in cost overruns will begin arbitration in Miami next week. The first dispute to be heard by the arbitration court will be a $180 million claim over the cost of draining an area to create work space near the Pacific locks of the 50-mile (80-km) long canal. The project’s contract states that if a disagreement between two parties arises during any part of the project, the two sides must first analyze the other side’s claim and then head to an adjudication board. In the event that these two measures cannot bring an agreed upon solution, the dispute would then head to arbitration.