We wish everyone a very Merry Christmas
a very Happy New Year 2015!
Our own Ben Turner (future Dr. Turner!) was lead author on a report by the Pacific Earthquake Engineering Research Center (PEER) on liquefaction and lateral spreading effects on bridges. The report is titled “Evaluation of Collapse and Non-Collapse of Parallel Bridges Affected by Liquefaction and Lateral Spreading”. Ben’s coauthors are Dr. Scott J. Brandenberg and Dr. Jonathan P. Stewart of the Department of Civil and Environmental Engineering at UCLA. From the abstract:
The Pacific Earthquake Engineering Research Center and the California Department of Transportation have recently developed design guidelines for computing foundation demands during lateral spreading using equivalent static analysis (ESA) procedures. In this study, ESA procedures are applied to two parallel bridges that were damaged during the 2010 M 7.2 El Mayor-Cucapah earthquake in Baja California, Mexico. The bridges are both located approximately 15 km from the surface rupture of the fault on soft alluvial soil site conditions. Estimated median ground motions in the area in the absence of liquefaction triggering are peak ground accelerations = 0.27g and peak ground velocity = 38 cm/sec (RotD50 components). The bridges are structurally similar and both are supported on deep foundations, yet they performed differently during the earthquake. A span of the pile-supported railroad bridge collapsed, whereas the drilled-shaft-supported highway bridge suffered only moderate damage and remained in service following the earthquake. The ESA procedures applied to the structures using a consistent and repeatable framework for developing input parameters captured both the collapse of the railroad bridge and the performance of the highway bridge. Discussion is provided on selection of the geotechnical and structural modeling parameters as well as combining inertial demands with kinematic demands from lateral spreading.
This report is part of Ben’s work on his doctoral dissertation. You can download the report by clicking on the linked citation below.
Turner, B., Brandenberg, S.J. and Stewart, J.P. (2014). “Evaluation of Collapse and Non-Collapse of Parallel Bridges Affected by Liquefaction and Lateral Spreading”, PEER Report 2014/10, Pacific Earthquake Engineering Research Center, University of California, Berkley, August, 2014, 94pp.
DBA is on the design-build team that is replacing the Goethals Bridge for the Port Authority of New York and New Jersey (PANYNJ). We are not able to post much about the project or our involvement due to security agreements. However, the PANYNJ has a public website for the project (http://www.panynj.gov/bridges-tunnels/goethals-bridge-replacement.html) that has several webcams. As is the case with most big projects these days, the webcams are a common feature and show some great views of the project.
To give you an idea of what the project involves, here is a summary from the PANYNJ site:
The replacement bridge will be located directly south of the existing bridge and will provide:
- Three 12-foot-wide lanes in each direction replacing the current two narrow 10-foot-wide lanes
- A 12-foot-wide outer shoulder and a 5-foot-wide inner shoulder in each direction
- A 10-foot-wide sidewalk/bikeway along the northern edge of the New Jersey-bound roadway
- Improved safety conditions and performance reliability by meeting current geometric design, structural integrity, security and seismic standards, and reduces life-cycle cost
- A central corridor between the eastbound and westbound roadway decks, sufficient to accommodate potential transit service
- State-of-the-art smart bridge technology
The project also includes the demolition of the existing bridge upon completion of the replacement bridge.
You can learn more about the project at the same web site. There is also a site for the current bridge, including history of the construction, etc.
We have added a link to the NCHRP Report No. 697 Design Guidelines for Increasing Lateral Resistance of Bridge Pile Foundations. This report was published in 2011 and authored by Kyle Rollins, Pd.D., P.E. of Brigham Young University and our own Dan Brown. Dr. Rollins is a Professor in Geotechnical Engineering specializing in earthquake engineering and soil improvement.
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.
Be sure to browse all of the nifty reports and projects in geotechnical and foundation engineering at TRB here.
Also check out our Publications page regularly for new postings.
DBA is please to announce the addition of two new members: Robert M. Saunders, P.E. and Benjamin Turner, P.E.
Rob is a graduate of the University of Tennessee (BSCE and MSCE) with 11 years of experience. He began his career at S&ME working with our own Tim Siegel and for the last 8 years has been with GEOServices, LLC in Knoxville. He has a broad design background, specializing in analysis and design of earth retention systems and deep foundations. His experience with earth retention systems includes design and construction of soil nail walls, soldier pile walls, anchored systems, temporary shoring, and mechanically stabilized earth walls. His experience with deep foundation design includes lateral response analysis of deep foundations and design of deep foundation in karst geology. Rob has been involved with several major projects for private companies and public agencies including Foothills Parkway in Blount co., Tennessee, Interstate 240 expansion in Memphis, Tennessee, and Bridgeforth Stadium at James Madison University.
Rob will be located in Knoxville, Tennessee with Tim Siegel.
Ben is currently pursuing a 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.
Ben will be working part-time as he can while completing his Ph. D. and will join DBA full time after completing his studies, staying in the Los Angeles, California area.
Welcome to both Rob and Ben!
We’re almost done with an upgrade to our website. With more than 50% of our site traffic now coming from smartphones and tablets, we needed a responsive web design, i.e., one that provides “an optimal viewing experience—easy reading and navigation with a minimum of resizing, panning, and scrolling—across a wide range of devices (from mobile phones to desktop computer monitors that are used for video games as CSGO, with the best mouse cs go and other hardware).” So the site now detects the type and size of your device and reshapes its presentation of the content while keeping the visual design.
That visual design is new, too. We’re using the Twenty Fourteen theme by WordPress, in part because of its ‘magazine style’ presentation of blog content. At the top of the home page, we now feature six blog posts, each with a featured image or photo. Clicking on the title or the photo of any of those takes you to that blog post where a larger version of the photo and the complete content is displayed. If you are looking for black ops 2 hacks on call of duty game, visit iwantcheats.net for more information. Other blog posts that aren’t selected by us to be featured will appear in the usual reverse chronological order on the blog/home page.
Lastly, we’re now showing excerpts of all blog posts on the home page rather than the entire contents of each post as before. This allows you to more quickly scan the latest posts, while giving you enough of a glimpse of each one to help you decide whether it interests you enough to click on it.
If you notice any problems with the new site, we’d appreciate hearing from you via our Contact Us page.
Dr. Dan Brown has joined the DFI Educational Trust Board and the DFI Board of Trustees as treasurer, effective January 1, 2014. Dr. Brown is recognized as one of America’s leading authorities on the construction and design of deep foundations for transportation structures. After 22 years on the faculty at Auburn University, Dr. Brown remains active in deep foundation practice through his consulting firm, Dan Brown and Associates. He has been recognized with the DFI Distinguished Service Award, ASCE Martin Kapp Foundation Engineering Award and the ADSC Outstanding Service Award.
David Coleman of Underpinning & Foundation Skanska, has been elected to a second five-year term as Trustee (2014-2019), and Roger Healey of Goettle, was elected to second two-year term as At-Large Trustee (2014-2016).
The elected officers for the Board of Trustees in 2014 are:
Chair: David Coleman
Vice Chair: M. Byrl Williams
Treasurer: Dan Brown
Secretary: Dan Dragone
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.
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.”