Wishing a Merry Christmas and a Happy New Year to all!
Wishing a Merry Christmas and a Happy New Year to all!
The blogosphere, as the world of blogging is sometimes called, is always changing as blogs come and go. A new one focusing on geology education is geologydegree.org. This is a new blog intended to promote the study of geology. A recent post called Geology Online: 105 Websites That Rock included our very own blog as well as that of one of our good friends, GeoPrac.net by RockMan (aka Randy Post). While DBA (and others listed, including GeoPrac.net) are not strictly geological blogs or websites, what we do includes a lot of geology as we design foundations to bear in or on rock. Understanding the geology of a site is also important to understand the soils that are present above the bedrock. Take a look, especially if you have a young’un (that’s Southern for young one, or child) at home that may find geology or geotechnical engineering interesting.
Image source: lohud.com
The design-build team Tappan Zee Constructors that is building the Tappan Zee Bridge is installing the over 200-ft long steel pipe piles using a relatively simple concept to mitigate vibration impacts on fish – a bubble curtain. Such curtains have become more common as an approach to mitigate potential impacts (pardon the pun) on aquatic life when large piles are driven over water. The vibrations from the hammer impact on the pile during driving are reduced or dampened by a curtain of bubbles generated around the pile by compressed air. An item in the December 26th ASCE Smart Brief linked an article in The Journal News (White Plains, NY) highlighting the use of the curtain on the Tappan Zee project.
A rubber-looking sleeve covered the hammer where it met the pile, dampening some of the noise in the air. Underwater, however, it was a curtain of bubbles serving as the aquatic equivalent of earplugs for fish and other creatures in the Hudson River.
Aluminum rings are slid over the pilings like the rings on a shower curtain rod before any banging starts. Air pumped into the rings produces a sheath of bubbles in the water around the pile. The froth generated in the water is called a bubble curtain.
“Bubble curtains are designed to protect the fish in the area from the noise generated by the hammer impact below the water level,” said Walter Reichert, project manager for Tappan Zee Constructors. “This divides the water into basically two sections. It greatly reduces the sound waves.”
The Wisconsin DOT was set to request bids this week for repairs to the Leo Frigo Memorial Bridge on I-43 in Green Bay, with an anticipated start of construction on November 4th and reopening of the bridge on January 17th. The repair will consist of using drilled shafts installed adjacent to the existing piers with a post-tensioned extension of the pile cap to transfer the loads to the shafts. A schematic of the design from Wisconsin DOT (via Milwaukee Wisconsin Journal Sentinel)
Scot Becker, director of the Bureau of Structures and the state’s bridge engineer, said the fix will consist of installing four concrete shafts beneath five affected piers to take over support from corroded underground steel structures, called pilings. Then, the bridge itself will be jacked up 2 feet, and concrete and steel will be poured to keep the bridge in position.
The bridge, which spans the Fox River in Green Bay, has been closed since late September, after pilings became corroded and buckled under one of the piers, causing a 400-foot-long section of the bridge to sink 2 feet. Since then, it has drooped another half inch, and the state is monitoring the bridge for further movement.
An investigation concentrating mainly in the area from Quincy St. to the Fox River found that soil surrounding the pier contained industrial byproducts over wetlands, which caused the corrosion.
Temporary supports are already being installed by Lunda to shore up the sagging spans until the repairs can be completed.
The Green Bay Press Gazette has a page archiving all of their stories, videos, photos, etc. concerning this event.
Image: From GreenBayPressGazette.com
Early indications are that the settlement of the pier at the Leo Frigo Bridge in Green Bay, Wisconsin is the result of corrosion of the piling that supports the pier. Randy Post over at Geoprac.net has a post up with video and a link to this story in the Green Bay Gazette Press. From the story:
Corrosion of steel pilings below a support pier on the Leo Frigo Memorial Bridge in Green Bay caused Pier 22 to buckle last week, creating a long, deep dip in the bridge deck and forcing the bridge’s indefinite closure.
The 100-foot-long pilings under the pier were degraded from a combination of water and the composition of soil surrounding the bridge support, Wisconsin Department of Transportation officials said Thursday.
It appears that the suspect piers are in an area of fill, the composition of which may be contributing to the corrosion of the piles:
The investigation is focused on the area from the Fox River east to North Quincy Street on the east side of the bridge, where fill materials like foundry sand and organic materials are part of the soil profile.
“We’ve encountered all kinds of different things,” Buchholz said about soil samples in that area.
In addition to investigating the cause of the settlement of the pier, the bridge has been inspected by the Wisconsin DOT and is not in danger of collapse. As a precaution, the bridge remains closed during the investigation.
Picture Source: nbcchicago.com
While several of the DBA staff were at the DFI 38th Annual Conference on Deep Foundations last week, we received texts and calls from colleagues wondering if we had been called about the apparent foundation failure at the Leo Frigo Memorial Bridge in Green Bay, Wisconsin. As of now, DBA has not been asked to be involved with the evaluation. The Wisconsin DOT is currently investigating. Our friend, Randy Post over at Geoprac.net has a post on the event, including a CNN video report that also recounts some other more dramatic bridge failures that were NOT due to foundation failures.
This bridge was built in 1980 and the “failure” is limited to a single pier that has subsided or settled a couple of feet in a rather sudden manner.
Actual failures of a foundation are rare, so if this is such a case, this will make a very interesting case history once the cause is determined. Stay tuned for more developments.
The GeoWorld professional network is pleased to announce the development of their latest innovative online tool: The Geo-Technical Forums! The new forums were a request by a number of individuals and committees of ISSMGE and have some features that aim to satisfy professional needs for communication about technical topics within the geo-community. This launch comes just a few weeks after the GeoWorld community voted the Technical Forums, as their most needed online tool for geoprofessionals.
The staff of Geoengineer.org has spent months working on the development of these new forums, which constitute at the same time a major upgrade of the forums previously available on Geoengineer.org. They are now live and available to the 3,000 GeoWorld members! If you are not yet on GeoWorld- The Professional Online Networking Tool for Geoprofessionals, you can sign up for free in just a few minutes here: www.mygeoworld.info
An advantage GeoWorld has (that will continue to grow) is that it focuses solely on the geoprofessions as opposed to general business or other broader categories.
I admit that I have not yet spent a lot of time on forums of any sort, but many people find them to be a useful tool to exchange information, professionally network, and make contacts in the industry. Perhaps I’ll find or make the time to cruise around them soon and report back.
Image Source: Star Telegram.com
Very carefully, of course! (You knew that was coming!)
DBA has had the pleasure of consulting with Sundt Construction on their effort to replace the West 7th Street Bridge over the Trinity River in Fort Worth, Texas. Our role has been to provide geotechnical consulting for the heavy lifts of the arches, as well as a VE design on a secant wall.
West 7th Street is a major artery into downtown Fort Worth. From the City of Fort Worth:
The aging Seventh Street Bridge, a popular east-west thoroughfare that connects downtown to the Cultural District, is due to be reconstructed.
The original span was built in 1913 and was expanded in 1953 when the Trinity River was rerouted and the surrounding levees were built. Although the bridge has been determined safe to use, beams, girders and the deck of the 1913 section are deteriorating.
To reduce the impact of closing the bridge, Sundt has installed new drilled shaft foundations on either side of the existing bridge. The twelve, 163-foot long, 300-ton concrete arches were fabricated off-site on the west side of the river. Large trailer dollies with 120 wheels move the arches from the yard to the site. Large cranes from Burkhalter (heavy lift and transport specialist) pick the arches from the dollies on the existing bridge and set them on the new foundations. The bridge is closed or partially closed during each lift. Once all of the arches are in place, the bridge will be closed to demolish the existing structure and build the new deck between the pairs of arches. The compete closure is supposed to last only 150 days.
Here is a time lapse video of the first arch being set:
The first arches were set over the weekend of May 11-12. Here are some links to video and articles:
TxDOT West 7th Street Bridge You Tube Channel – includes time lapse of first arch.
Bonus: For all of those that love “big boys with big toys” , make sure and check out the Burkhalter web site.