In the forward of the report, Andrew Lemer of TRB writes:
NCHRP Report 697: Design Guidelines for Increasing the Lateral Resistance of Highway- Bridge Pile Foundations by Improving Weak Soils presents design guidance for strengthening of soils to resist lateral forces on bridge pile foundations. Lateral loads may be produced by wave action, wind, seismic events, ship impact, or traffic. Strengthening of soil surrounding the upper portions of piles and pile groups—for example by compaction, replacement of native soil with granular material, or mixing of cement with soil—may be more cost-effective than driving additional piles and extending pile caps as ways to increase the bridge foundation’s capacity to resist lateral forces associated with these loads. This report presents computational methods for assessing soil-strengthening options using finite-element analysis of single piles and pile groups and a simplified approach employing commercially available software. The Additional resources and design guidelines will be helpful to designers responsible for bridge foundations likely to be exposed to significant lateral loads.
DBA has had the pleasure of working with T.Y. Lin and Slayden–Sundt JV in their effort to replace the Sellwood Bridge over the Willamette River in Multnomah County, Oregon, near Portland. Designed by Gustav Lindenthal, the existing Sellwood Bridge was constructed in 1925 to replace the Spokane Street Ferry, connecting the communities of Sellwood and West Portland. In response to budget issues at the time, the Sellwood Bridge design was scaled back to minimize costs. Fast forward to 2014 and the existing Sellwood Bridge is now the only four-span continuous truss highway bridge in Oregon and possibly the nation. The bridge is extremely narrow, two lanes, no shoulder or median, and one small 4-ft sidewalk. In addition to these shortcomings in design with respect to the modern age, the west end of the bridge was constructed on fill, and the hillside above the bridge is now slowly sliding toward the river. Ground movements have caused some of the girders to crack. Furthermore, the existing bridge was not designed to any seismic standards which present a major concern given the bridge’s location in the seismically active Pacific Northwest.
The new Sellwood Bridge will be a deck arch structure with three arches supporting the deck of the main river spans and is designed to the latest seismic standards. It will feature two 12-ft travel lanes, two-12 ft shared use sidewalks, and two 6.5-ft bike lane/emergency shoulders. Multnomah County is using the existing bridge truss on temporary pile foundations as a detour to save time and money during construction with minimal impact to traffic, people can always get quick loans without credit check process at any time if they have financial problems. According to www.cyclonebuildings.com, the original bridge truss was shifted on January 19, 2013. Complicating the move was the enormity of the bridge, an 1100-ft single truss weighing 3400 tons. In addition to the size and weight of the span, old age and its curved alignment added to the technical challenges. The impressive move took only 14 hours. The detour bridge is currently fully operational and will continue to carry traffic until the summer of 2015 when the new bridge is scheduled to open.
DBA played key roles in the design and construction of the main arch piers. As part of the VE Design, DBA assumed engineering responsibility for the 10-ft diameter drilled shafts supporting Piers 4, 5, and 6 (4 & 5 being in the river and 6 on the eastern shore). The lengths of these shafts ranged from 81 ft to 225 ft through a number of subsurface conditions which posed many challenges to construction. Subsurface conditions ranged from large loose cobbles/gravel (Catastrophic Flood Deposits) to cemented cobbles and gravel (Troutdale Formation), to very hard intact basalt bedrock. Due to the challenging geologic conditions and variability of these conditions across the site, DBA implemented an observational method in which the final shaft length determination was made on the basis of our on-site observations in relation to a set of predefined criteria. This approach provided the necessary flexibility to efficiently confront different subsurface conditions in a timely manner. Drilling subcontractor Malcolm Drilling successfully completed construction of the last of these shafts in mid-October 2013.
You can learn more about the bridge and the project at Multnomah County’s website, SellwoodBridge.org. The website has current field work updates, photo gallery, history of the project, and a live construction camera with daily, weekly, and monthly time-lapse videos. There is also a time-lapse of the moving of the old truss.
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.”
Work to begin lifting the sagging portions of the Leo Frigo Memorial Bridge on I-43 in Green Bay, Wisconsin is scheduled to begin Tuesday. According to the Green Bay Press Gazette, Zenith Tech Inc. is working on the repairs. It will be a BIG lift, indeed…..
Raising the troubled Leo Frigo Memorial Bridge back into place will be a task equivalent to hoisting an entire fleet of 747s into the air.
Experts have calculated that the sagging section of Green Bay’s distressed bridge weighs more than 3 million pounds, or about 1,600 tons.
Zenith Tech crews are expected to spend several days using hydraulic jacks to boost the Leo Frigo back into position — a process that will go slow, by design.
Starting with the northbound lanes, Zenith Tech will insert 10 hydraulic jacks beneath the bridge deck and operate them all simultaneously to raise the platform. Each jack will be exerting enough pressure to support 183,000 pounds, although Dreher said their capacity is 50 percent greater than that — just in case it is needed.
Dreher said the jacks will be calibrated carefully to operate in perfect unison, so there is no risk of the bridge deck leaning one way or the other as it is elevated.
“You can’t just go in there and start jacking away,” he said. “It definitely takes some coordination and good communication.
A very challenging and interesting repair project. Kudos to the Wisconsin DOT and all involved in getting the repairs done quickly.
As reported by the Minneapolis Star Tribune, Case Foundation recently finished constructing 40 drilled shafts at the St Croix River Crossing Project. Since early June, Case has been working at a feverish pace to construct the drilled shaft foundations for the new extradosed bridge between Minnesota and Wisconsin. As of November 8th, all of the drilled shafts are officially complete. General contractor Kramer is working to finish the pier footings and support tower bases by early 2014. Soon, the joint venture of Lunda and Ames will begin construction of the $380 million bridge superstructure.
As MnDOT’s foundation consultant for the project, DBA has been on site during much of the foundation construction over the past five months. Some pictures taken during this time, along with several pictures from MnDOT are available for viewing on our Picasa Page. More pictures and information can be found on the project website and Facebook Page, and the project can be viewed live via webcam. Previous DBA blog posts about the main project and the predesign load test program can be found here.
DBA is pleased to wrap up its role on the St Croix Crossing Project with a very positive outlook. The drilled shaft construction proceeded on schedule and as planned without unexpected challenges, and our strong client relationships with MnDOT continued to grow stronger. It was also nice to see familar faces from Case, Braun Intertec, and Parsons Transportation Group, many of whom we worked with us at Hastings. We very much look forward to working with these partners again in the future!
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.
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.
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.
History was made on Sept. 7, 2013when state and local officials cut the ribbon on the new Hurricane Deck Bridge during a ceremony held in the center of the new structure. The bridge officially opened to traffic in the late evening on Monday, Sept. 9. The original bridge is now closed and will be prepared for demolition during the remainder of 2013. Final demolition will take place in the spring of 2014.
Cover Image of the Hastings Mississippi River Arch Bridge
The featured article in the July/August 2013 issue of Deep Foundations, the magazine of the Deep Foundations Institute, is coauthored by Dan, Paul, and Rich Lamb, P.E., of the Minnesota Department of Transportation (MnDOT). The article summarizes how load testing has been used successfully as part of the foundation design process by DBA and MnDOT on five major bridge projects along the Mississippi and St. Croix Rivers during the last 10 years and the lessons learned from these successive projects. The featured bridge projects include two major design-build projects, the emergency replacement of the I-35W St. Anthony Falls Bridge (2007) and the Hastings Mississippi River Arch Bridge (2011). The other traditional design-bid-build projects include the I-494 Wakota Mississippi River Bridge, the U.S. Hwy 52 Lafayette Mississippi River Bridge, and the St Croix River Bridge. As is often the case, each of these projects presented unique geological and hydrogeological challenges to foundation design – despite the projects all being within 30 miles of each other – including thick layers of highly organic compressible soils overlying bedrock, layers of cobbles and boulders, artesian groundwater conditions, and bedrock ranging from weak weathered sandstone to very hard dolostone. These varying conditions resulted in the use and testing of a variety of foundations. Load testing “with a purpose” has proven to be an integral part of the design and construction process on these projects, as the load tests were not simply for verification of a design but provided valuable information used to optimize the designs and provide quality assurance of the construction practices.
Please read the full article here or in a copy of Deep Foundations, a bi-monthly magazine published by the Deep Foundations Institute. DFI is an international technical association of firms and individuals involved in the deep foundations and related industry. More information about DFI and how to become a member can be found at www.dfi.org.
Also see our Projects Page for more about some of these projects and our other major projects.
Specialists in Deep Foundation Design, Construction, and Testing and Slope Stability Problems