The long anticipated update to FHWA GEC 10 Drilled Shafts: Construction Procedures and Design Methods has finally been released by FHWA, The same team that authored the major update in 2010 that shifted design from ASD to LRFD also completed this update: Dr. Dan Brown, P.E., D.GE, and Dr. John Turner, P.E., D.GE of DBA, Dr. Erik Loehr, P.E. of the University of Missouri and DBA, and Mr. Ray Castelli, P.E. of WSP.
This version is an update of the 2010 publication. A complete list of changes made since 2010 is in the opening chapter. Some of the revisions include:
streamlining materials covered in other GEC publications (for example, site investigation and lateral loading) to focus on aspects particular or unique to drilled shafts;
updates to reflect the evolution of construction procedures, tooling, materials, drilling fluids, and concrete placement;
updated design equations for axial loading, particularly for earthquake loading;
Construction of drilled shafts continues as the superstructure begins to emerge over the skyline between Elizabeth, NJ and Staten Island, NY. The new bridge will be a dual-span 1,983-ft long cable-stayed bridge with approach spans of over 2,500 ft on each side. The bridge is supported on over 200 drilled shaft foundations ranging in diameter from 4.5 ft to 10 ft and socketed into Passaic Formation siltstone.
The GBR is a Public-Private Partnership (P3) that represents a major milestone for the PANYNJ in its distinguished history of bridge building in the greater New York City metropolitan area. The existing Goethals Bridge along with the Outerbridge Crossing and the Bayonne Bridge comprise the three Port Authority bridges connecting Staten Island with New Jersey. The Goethals Bridge and the Outerbridge Crossing are cantilever truss structures and both opened on the same day in 1928. They were designed by J.A.L. Waddell under the supervision of the eminent engineer Othmar H. Ammann (1879-1965), who was the designer of many other iconic bridges in the NY City area including the Bayonne Bridge (1931), the George Washington Bridge (1931), and the Verrazano Narrows Bridge (1964). The designer of record for the replacement Goethals Bridge is Parsons Corporation, which is the successor firm of Robinson & Steinman, whose principal David B. Steinman was also a notable NY area bridge designer and a contemporary and rival of O.H. Ammann.
Each main pylon tower of the GBR is supported on a group of six 9-ft diameter drilled shafts and each anchor pier is supported by two 10-ft diameter shafts. Approach piers are two-column bents with each column supported on a rock-socketed drilled shaft.
DBA is the foundation design engineer of record and this project provides an example of how rock-socketed drilled shafts can provide a reliable and cost-effective means of supporting a major bridge by taking advantage of the high resistances that can be achieved. Key factors involved in taking advantage of rock sockets for this project were: (1) load testing to demonstrate high axial resistances (>30 ksf side resistance and >300 ksf base resistance), (2) utilization of all relevant construction QC/QA tools to ensure that rock sockets are constructed in a manner that is consistent with construction of the load-tested shafts that provide the basis of the design, (3) close collaboration between all members of the design-build team, and (4) adequate subsurface characterization, especially a thorough characterization of rock characteristics and their effect on socket resistances. Load testing for this project demonstrates that side and base resistances can be used in combination to design rock socketed shafts for axial loading. This approach avoids the use of unnecessarily deep sockets, thereby minimizing the associated construction risks and costs.
Last spring, DBA conducted a construction phase load test program for a U.S. Army Corps of Engineers floodwall improvement project along the Missouri River in Kansas City, Kansas. Located on property owned and maintained by the Kansas City Board of Public Utilities (BPU), the BPU floodwall was slated for structural improvements including a series of buttresses founded on 24-in drilled shafts. As part of the project contract a load test program performed under the direction of a qualified P.E. and D.GE was required. General contractor L.G. Barcus & Sons, Inc., secured our Paul Axtell, P.E., D.GE as the qualified load test expert. DBA teamed up with load testing subcontractor Applied Foundation Testing, Inc., to perform the static load tests.
The load test program requirements included three test shafts, a statically loaded axial test shaft, a statically loaded lateral test shaft, and a combined statically loaded axial and lateral test shaft. The required combined lateral and axial test shaft provided some unique challenges with respect to applying the loads and collecting data. As can be seen in the picture above, the axial load was applied using dead weights.
We have added selected pictures from this unique project to our web albums, which can be viewed here.
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.
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.
Earlier this week, officials from the Minnesota and Wisconsin departments of transportation (MnDOT and WisDOT) met for an official groundbreaking ceremony on the projected $629 million bridge and highway project that will connect Oak Park Heights, Minnesota, to St. Joseph, Wisconsin, just south of Stillwater, Minnesota, as highlighted in yesterday’s edition of The Minneapolis St. Paul Business Journal. The new bridge will replace the 80-year-old Stillwater Lift Bridge and relieve traffic congestion in nearby Stillwater.
DBA has been retained by MnDOT as the lead geotechnical consultant and foundation designer for the extradosed river bridge. Last summer, DBA aided MnDOT in the design and oversight of a load test program described in my blog post, “DBA Wraps Up Load Test Program and Proceeds with Design on St. Croix Bridge.” Following final design, which took place over the fall and winter, construction of the foundations will begin next week with the installation of a technique shaft. DBA will participate in construction as well, providing construction observation and review of the technique shaft and at least one shaft at each of the five production piers. Edward Kraemer & Sons, Inc. of Plain, Wisconsin, has been selected as the general contractor for the foundation contract with sub-contractor Case Foundation Company of Chicago, Illinois, performing the drilling. The extradosed bridge will feature five main river towers, each resting on two footings supported by a 4-shaft group of 8.5-foot drilled shafts, socketed 25-feet or more into sandstone bedrock.
I hope to have some more updates soon with some pictures following my upcoming site visits to observe the construction operations. In the mean time, you can stay updated by visiting the MnDOT project page and watching the “action” live via the construction webcam.
Note: Okay – I’ll admit – I also do a blog for the Geo-Institute Deep Foundations Committee. as such, there are often things that I feel should be posted at both – to get the widest possible audience! So, if you have already been over there, this post will look very familiar. It is much easier to reuse a post written by yourself. – Robert
As a continuing effort to implement the LRFD design methodology for deep foundations in Louisiana, this report will present the reliability-based analyses for the calibration of the resistance factor for LRFD design of axially loaded drilled shafts using Brown et al. method (2010 FHWA design method). Twenty-six drilled shaft tests collected from previous research (LTRC Final Report 449) and eight new drilled shaft tests were selected for statistical reliability analysis; the predictions of total, side, and tip resistance versus settlement behavior of drilled shafts were established from soil borings using both 1999 FHWA design method (O’Neill and Reese method) and 2010 FHWA design method (Brown et al. method). The measured drilled shaft axial nominal resistance was determined from either the Osterberg cell (O-cell) test or the conventional top-down static load test.
It may not have been intended as such, but we will “claim” this large rock core on the Mississippi River as a “geotechnical monument”. At the site of the new I-70 crossing over the Mississippi River in St. Louis, one of the 11-foot diameter limestone rock cores retrieved from one of the rock sockets drilled for the bridge foundations has been placed on the river bank along with a sign. Our own David Graham stopped by and had some pictures taken when on a personal trip their last year. So, the next time you are in St. Louis, look for the big hunk of rock on the west bank (St. Louis side) near the new bridge north of the Arch.
Lateral Statnamic test, picture by David Graham of DBA, click here for a YouTube video
DBA has been selected by MnDOT as a geotechnical and load testing consultant for the design phase load test program and foundation design of a new bridge crossing the the St. Croix River near Oak Park Heights and Stillwater, Minnesota. The new bridge will carry State Highway 36 across the St. Croix River between Minnesota and Wisconsin. Currently, Highway 36 is carried on an 80-year old two-lane vertical lift bridge in downtown Stillwater. The new bridge will divert the heavy through traffic away from the historic downtown center and reduce travel time for commuters. The iconic lift bridge will be converted to a pedestrian and bicycle only structure.
Work began this summer on the load test program which consisted of one 8-foot test shaft, two 24-inch driven steel pipe piles, and two 42-inch driven steel pipe piles, all installed in the St. Croix River along the alignment of the new bridge. Local contractor Carl Bolander & Sons Co. was selected as the general contractor for the load testing program. Bolander self-performed the installation of the test piles and sub-contracted the construction of the test shaft to Case Foundation Company, of Chicago, Illinois. Axial load testing of the test shaft was performed by Loadtest, Inc., of Gainesville, Florida, using Osterberg Cells (O-cells). Dynamic testing of the driven piles using the pile driving analyzer (PDA) was performed by local geotechnical consultant Braun Intertec. Axial testing of the driven piles and lateral testing of the shaft and one of each size pile was performed using the Statnamic Device by Applied Foundation Testing, Inc. (AFT), of Jacksonville, Florida. DBA provided pre-test recommendations, assisted MnDOT in construction oversight, provided analysis and review of the test results, and made design recommendations based on the test results.
Following the successful load test program, DBA is working with MnDOT’s structural design consultants for the project, HDR, Inc. and Buckland & Taylor Ltd. to optimize the bridge design. Already, the design team has been able to lengthen the bridge spans and eliminate a river pier as a result of the load test results, as was recently reported by Minnesota Public Radio (MPR). Also, because the total number of drilled shafts required to support the main pier towers has been reduced, construction on the foundations will been moved up to 2013 rather than the original estimated start date in 2014, also reported by MPR.