Category Archives: Miscellaneous

Bridge Construction, Bridge Foundations, Drilled Shafts, Foundation Design, Instrumentation, Miscellaneous, Slope Stability

Instrumentation at US 231 bridge and Slide

(Written by Andy Boeckmann – DBA)

After successful design and construction of the US 231 emergency slide repair in Lacey’s Spring, Alabama, DBA shifted gears to install a state-of-the-art monitoring system for the project. The monitoring system allows DBA and ALDOT to remotely detect any movement of the drilled shafts, changes in groundwater levels, and movement of the slope, itself.

The monitoring system includes ShapeAccelArray (SAAV) devices to measure displacement profiles with depth. SAAVs, which are manufactured by Measurand, consist of a chain of rigid segments, each 1.5-ft long and about 1-inch diameter. DBA installed 27 SAAV devices at US 231. Each of the 24 drilled shafts has one SAAV, which DBA installed in a 1-inch conduit welded to the drilled shaft reinforcement and emerging from the top of the grade beams connecting the shafts. The other three SAAVs are “free-field” SAAVs, installed in the soil between bridge bents. DBA worked with ALDOT’s drill crews to install the free-field SAAVs.

ALODT drill crew installing a free-field SAAV under the Northbound bridge.

 

Completed free-field and foundation instruments at Bent NB4.

 

DBA also worked with the ALDOT drill crews to install vibrating wire piezometer devices at six locations across the site. Each location includes two piezometers, one in the soil and one just below the top of rock. The piezometers were installed using the fully-grouted method. The piezometers measure pore pressure, which DBA uses to interpret groundwater conditions at the site.

 

Datalogger atop a vibrating wire piezometer.

 

All of the instruments are connected wirelessly to two central hubs that collect the data. The hubs are solar powered.  One of the hubs is equipped with a cellular modem that facilitates remote collection of the data.  RST Instruments manufactures the monitoring equipment as well as the vibrating wire piezometers.

Housing for SAAV devices installed in drilled shafts.

 

R-star hub and solar panel mounted to SB Bent 6.

 

Inside of data collection hub.

 

Results of the monitoring program indicate the foundation system is performing as designed. The US 231 structure has passed its first wet season with flying colors. Despite several periods of heavy rain that resulted in localized slope movement, the drilled shafts have shown only very small movement, typically less than 0.05 inch. The movement shown in the shafts indicates they are resisting loading from the slope movement, but with plenty of reserve capacity. The monitoring system has successfully captured realistic results from all instruments, including the drilled shaft and free-field SAAVs and piezometers.

Piezometer data shows strong correlation between rainfall and increases in groundwater levels.
Example of SAAV drilled shaft displacement. Shaft displacements are very small, typically less than the stated accuracy of the SAAV devices.

The monitoring system is more than just bells and whistles: it is an integral part of DBA’s design philosophy for the US 231 project. DBA engineers were able to implement the innovative strategy of drilled shafts through an active landslide because we knew performance of the foundation system would be actively monitored. This strategy represents a modern take on the observational method, which has represented best geotechnical engineering practice since the profession originated. DBA will also use results of the monitoring program to inform future designs, consistent with our commitment to using state of the art to improve the state of practice.

To read more in detail about the design and construction of the bridge foundations, we published an article i nthe April 2021 issue of Foundation Drilling Magazine:

Thompson, W.R. and Dapp, S.D. (2021). “Innovative Landslide Solution”, Foundation Drilling, Vol XLII, No. 3April 2021, pp51-62.

Bridge Construction, Bridge Foundations, Drilled Piles, Drilled Shafts, Foundation Design, Micropiles, Miscellaneous, Rockfall Hazard, Slope Stability

Two Major Bridges in Minnesota Open to Traffic

St. Crox Crossing Extradosed Bridge; photo courtesy of MnDOT

Two DBA bridge projects in Minnesota opened to traffic recently.  The St. Croix Crossing near Stillwater and the Highway 53 Relocation in Virginia.  Both projects are milestones for MnDOT.  The St. Croix Crossing is the first extradosed bridge in the Midwest and only the second extradosed bridge in the United States.  The new Highway 53 Bridge is the tallest bridge in Minnesota.

Following a ribbon cutting and dedication ceremony on the morning of Wednesday, August 2nd, the St. Croix Crossing saw its first traffic later that evening and has already alleviated traffic congestion  in downtown Stillwater,  as intended.  The interstate project was also heralded as a noteworthy example of government cooperation by The Wall Street Journal.

After officially breaking ground just shy of two years ago,  the new Highway 53 bridge opened to traffic on September 15th.  A dedication ceremony was held underneath the bridge that morning with Minnesota Lt. Gov. Tina Smith and Congressman Rick Nolan in attendance.  In  anticipation of the new bridge, the iron range quad cities of Virginia, Eveleth, Gilbert, and Mountain Iron held a four-day, multi-event festive, Bridge Daze, in August.

Hwy 53 Bridge Across The Rouchleau Pit; photo courtesy of OxBlue construction cameras

Miscellaneous

Merry Christmas and Happy 2017 from DBA!

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Wishing a Merry Christmas while wrapping our gifts and storing them in our Tippcontainere so nobody can get to them. And also a Happy New Year to all, especially the ones reading this post! Hopefully everyone can spend time with all of their families and loved ones to have a special evening this year, enjoy all the food, especially the allfitrecipes soup, and goodies that are going to given at dinner and get ready to celebrate the new year!

Miscellaneous

Websites That ROCK!

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, although most of the childs these days just like to play LOL.

Miscellaneous

Happy 2014 from DBA!

Here is to a very Happy New Year from all of us at DBA!  May the world of geotechnical and foundation engineering be full of fun surprises and challenging work for everyone!

 

P.S. We hope you had a very Merry Christmas season as well! (Images courtesy of the World Wide Web).

MerryXmas

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Bridge Construction, Bridge Foundations, Driven Piles, Miscellaneous

Bubble Curtain for Driving Piles at Tappan Zee

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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.”

Check out the article for some neat pictures and a cool video about the process (with hammer sounds!).  Here is a small picture gallery from lohud.com.

Bridge Foundations, Drilled Shafts, Foundation Testing, Miscellaneous

Leo Frigo Bridge–Repair Design

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.

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Bridge Foundations, Foundation Testing, Miscellaneous

Leo Frigo Bridge–Corroded Piling

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.

Bridge Foundations, Miscellaneous

Leo Frigo Memorial Bridge, Wisconsin–Foundation Failure???

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.

The Green Bay Press Gazette has this article with some video.  There is also an article noting that a petroleum pipeline is near the subject pier.

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.