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 and goodies that are going to given at dinner and get ready to celebrate the new year!
A lot has changed from a year ago at the TH 53 Bridge sight near Virginia, Minnesota. This time last year, the design-phase test pile program was wrapping up with three Statnamic load tests and we had just completed our initial geologic field investigation. Since then, significant excavation, rockfall protection, and foundation work has been completed. During summer and fall of 2015, DBA worked closely with contractors Hoover Construction and Pacific Blasting to maintain rockfall protection throughout the East Abutment and Pier 1 (East Pier) excavation process. Official ground breaking occurred last November and foundation work started shortly after. A total of 32, 30-in micropile foundations have been installed by Veit Specialty Contracting and Kiewet Infrastructure has completed a temporary causeway across the massive Rouchleau Pit by placing over 300,000 cubic yards of fill.
With the foundations of both piers complete, and the pier towers are starting to rise up, where they will carry the bridge deck 200 ft above. The abutments are also taking shape with rock bearing concrete footings now poured on both sides of the pit. The only foundation work left is to install tieback anchors at the East Abutment, which will reduce the lateral loading of the tall piers.
In a little over a year, the bridge is scheduled to open to traffic. You can keep track of the progress through the project web cam.
Well, we are at it again. The first 5 months of 2016 have seen us add three new faces to the DBA team. So now, drum roll, please………
Ali Leib, E.I.
Ali was a summer intern at DBA in 2014 and 2015 and joined us full time as a staff engineer in February. She is a recent graduate of the University of Tennessee (Go Vols!) where she completed both her B.S. and M.S. in civil engineering. While completing her M.S., she was a teaching assistant in charge of grading lab reports for the structural and geotechnical undergraduate labs. She was also a research assistant under Dr. Dayakar Penumadu, resulting in her thesis: “Effect of Particle Morphology on the Deformation Behavior of Sand under Monotonic Loading Conditions.” Unlike most of the rest of us, Ali insists that she will notbe conforming to the (mostly) standard DBA hair style. Ali will work in our Knoxville, Tennessee office.
Mark Madgett, P.E.
Mark received a BS and MS degree in Civil Engineering at the University of Tennessee, while working on research for TDOT to improve pavement design methods. He has worked in both consulting and construction for the last 22 years, focusing primarily on deep foundations in the Southeastern US. As a consultant, Mark gained extensive field experience with deep foundation construction techniques and the impacts on design. In 2006, he began working for Seaboard Foundations, opening a green field office in Tri-Cities TN as the district manager. In his role as design engineer for Seaboard Foundations, Mark has implemented design-build techniques in many markets (energy, institutional, commercial, transportation, and healthcare) that vastly improved the constructability and reduced the costs of deep foundation systems for his clients. Mark will also work outr of our Knoxville, Tennessee office.
Ben Turner, Ph. D., P.E.
Ben recently completed his Ph.D. in geotechnical earthquake engineering at UCLA with an emphasis on the transfer of forces between the ground and foundation elements during seismic loading. Prior to starting at UCLA, he worked for two years for the Los Angeles office of Shannon & Wilson, Inc. Ben worked in both construction and geotechnical firms while attending school for his B.S. and M.S. degrees. His experience includes: design, construction, and load testing of deep foundations; geotechnical earthquake engineering including soil-structure interaction, seismic hazard analysis, site response, liquefaction triggering analysis and mitigation of liquefaction-induced ground failure; and, characterization of structural behavior of reinforced concrete foundations. Here are two of the publications resulting from his dissertation work:
The St Croix Crossing Bridge is an extradosed bridge, which is something of a cross between a segmental box girder and cable-stayed bridge. The scale of the massive concrete segments can be seen in the picture above in comparison to the barge the segments are sitting on and some of the equipment in the background.
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.
TH 53 Bridge, artistic rendering courtesy of MnDOT
The official groundbreaking for the Trunk Highway (TH) 53 Bridge and Relocation Project occurred last week at the project site in Virginia, Minnesota. The bridge, which is the main element of the project, will span the Rouchleau Iron Ore Mine Pit. The project is scheduled to be completed in a brisk two years in order to allow for mining where a section of TH 53 is currently located. Upon completion the 1,100-foot long bridge will be Minnesota’s highest, with the roadway sitting approximately 330 feet above the bottom of the floor of the Rouchleau Pit. Kiewit was selected as the general contractor for the project with Veit Specialty Contracting as the foundation contractor.
Foundation construction will start in late November or early December with the installation of 30-inch diameter micropile foundations for the western pier of the three span, steel plate girder bridge. Although the foundation work is just about to get started, DBA has been hard at work on the project for over a year. DBA first got involved as a consultant to MnDOT for the design-phase load test program conducted last fall. Since then, DBA was contracted as the geotechnical engineer of record for the project. Working with bridge designer Parsons, DBA designed the bridge foundations, an anchored abutment, and rockfall hazard mitigation systems for this geologically challenging site. DBA has also analyzed several soil and rock slopes to verify stability of the bridge and roadway.
Most recently, some of us were on site to inspect some of the rockfall protection elements on the east side of the mine pit. Last week we spent two days climbing and repelling a on a portion of the eastern highwall, which is currently covered in rockfall protection drapery. The drapery was installed for the protection of workers excavating rock for the eastern bridge pier. The drapery was installed by Pacific Blasting in association with Hoover Construction. Some pictures from our drapery inspection visit are below.
For more information about the project, click here, and for our previous blog posts on this project, click here.
John and Paul provide some scale to this picture as they work their way down the drapery.
John concentrating as he inspects the drapery seam as he decends.
The Transportation Research Board (TRB) has released a synthesis report prepared by Dan and Robert on large diameter piles: NCHRP Synthesis 478, Design and Load Testing of Large Diameter Open-Ended Driven Piles. The report is a summary of the state of practice with regard to Large Diameter Open-Ended Piles (LDOEPs) in the transportation industry. We conducted a survey of state DOTs as well as interviews with private practitioners to summarize current practices as well as recommend best practices with regard to the selection, design, installation, and testing of LDOEPs. Several state DOTs are using LDOEPs more regularly where large foundation loads may exist and/or the piles are subject to significant unsupported length due to scour, liquefaction, or very weak surficial soils. Marine construction conditions also favor the use of these piles, particularly where pile bents might be employed to eliminate footings.
You can download a PDF of the report or purchase a hard copy at the link below.
DBA is currently working with structural designer Parsons to design what will be Minnesota’s tallest bridge. The bridge will span the currently inactive Rouchleau open pit iron ore mine near Virginia, Minnesota. MnDOT is moving the alignment of the existing Hwy 53 to make way for future mining in the area. DBA is the lead geotechnical designer on the project in addition to being contracted as MnDOT’s load test expert for the ongoing design phase load test program.
As part of our site investigation to gather information on rock fall and the site geology, five DBA engineers (John Turner, Paul Axtell, Tim Siegel, Nathan Glinksi, and David Graham) got up close and personal with the site by rappelling off the near vertical cut faces on either side of the Rouchleau pit! Traversing the over 200-ft tall cut faces of the nearly 2-billion year Biwabik Formation rock formation by rope and harness, we collected valuable geologic data. We also took some great pictures like the ones posted to our Google Photos account. In addition to the still pictures, we took some videos of a few rock fall tests, which are on our YouTube channel.
If you would like to know more about this interesting project on Minnesota’s Iron Range, you can check out our project summary sheet, visit MnDOT’s project page, or stay tuned to this blog for more updates. There is also an online article about the project that was recently published by Civil Engineering Magazine.
DBA has been working on an exciting new project currently under construction in downtown Sacramento, California: the new Sacramento Arena, known as the Entertainment and Sports Center (ESC). The ESC will be a multi-use, publicly owned indoor arena. The Sacramento Kings will be the primary tenant and the arena is expected to host other indoor sports and music concerts, as well. Once completed, the ESC will replace Sleep Train Arena as the home of the Kings. According to Kings Chairman Vivek Ranadive, the 17,500-seat arena will be “one of the most iconic structures on the planet … It’s going to put Sacramento on the world map.”
Turner Construction is the head of development for the new arena. Malcolm Drilling Company was awarded the contract to design and construct the foundation system. DBA worked closely with Malcolm to design Omega piles (a drilled and grouted displacement pile) to serve as the foundations for the new arena. The site presented unique design challenges, including liquefiable soil conditions and existing deep foundations from the demolished portion of the Downtown Plaza.
DBA’s design incorporates 18” and 24” Omega piles. An extensive site-specific load test program was performed to determine the axial resistances of the piles. Eight test piles were instrumented with strain gauges to measure the load distribution in the piles. Supplemental cone penetration testing was performed following load testing to better correlate the load test results with the subsurface conditions.
The piles were designed to resist ground motions from seismic events using site-specific ground curvature data developed by Pacific Engineering and Analysis. The piles were designed to resist the curvature at the anticipated pile section with only a single center reinforcing bar, eliminating the need to extend the entire cage to the bottom of the pile. This detail in the design is very important to ease the pile installation for the site conditions.
The final design incorporates a total of 952 piles to support the arena structure (346 18” dia. Piles and 606 24” dia. piles). The new arena is estimated to cost $477 million, with $255 million of that being funded by the City of Sacramento, it will even include the work of some of the top professional locksmith in the area to help secure the construction accesses from the ground up. The rest of the arena ($222 million) will be funded by the Sacramento Kings. Construction began October 29, 2014 and is planned to be completed by October of 2016.