Selection of Spread Footings on Soils to Support Highway Bridge Structures
Available Resources

New FHWA Manual on Spread Footings for Highway Structures

Selection of Spread Footings on Soils to Support Highway Bridge Structures Hot on the heals of the revised MSE Wall Manual, the FHWA has released another manual, this one on Spread Footings. Selection of Spread Footings on Soils to Support Highway Bridge Structures was authored by Naresh C. Samtani, PE, PhD, Edward A Nowatzki, PE, PhD and Dennis R. Mertz, PE, PhD. So what is this manual all about? I think the foreword by Scott Anderson, PE, PhD of the FHWA Resource Center says it best:


Geologic Hazards

City of Chilliwack, British Columbia to Pay $18M for Up to 42 Homes On Landslide

chilliwack_bc_landslide_neighborhood The Chilliwack Times reports that the City of Chilliwack will pay 80% of the assessed home value for up to 42 homes in an Eastern Hillside subdivision that are located on a slow moving landslide. The issue was first noticed in 2001 and several homes have had significant damage, but most are currently undamaged. The City denies any responsibility, but it’s legal counsel recommended a settlement. (Photo by Paul J. Henderson, Chilliwack Times)

Normally the geotechnical engineer for the subdivision would be held accountable. But apparently the slip surface is located 30-m below grade, much deeper than borings for a typical investigation for a subdivision. I wonder if there were any geologists consulted? Click through for a Google map view of the area and you can do your own armchair photogeology quarterbacking! Your heart does go out to the people losing their homes, they had no idea. But it could be worse, they could be in La Jolla and be getting squat.


Geofoam used on Pacific Street Bridge Project in Omaha, Nebraska

Geofoam Offers Performance and Efficiency, Streamlining Nebraska Traffic

Geofoam used on Pacific Street Bridge Project in Omaha, Nebraska[Editor] Geofoam is a great tool to have in your geotechnical toolbox. It can be used to reduce vertical loads to control settlement or to reduce lateral loads on bridge abutments or other structures. The Pacific Street Bridge Project in Omaha, Nebraska is one project that used geofoam for both of these purposes. In this article, author Nico Sutmoller, Geofoam Specialist with Insulfoam, LLC describes this excellent case study in the application of geofoam to meet the project objectives and provide aditional efficiencies during the construction phase. Nico, thanks for sharing with us! [/Editor]


Project Related

Voids Open as a Result of Tunneling Under Seattle’s Beacon Hill

image The Seattle Times (hat tip to ASCE SmartBrief) has reported that seven voids have been discovered above the Beacon Hill Tunnel with one opening up at the ground surface. The tunnel is being constructed by Sound Transit, the area’s transportation agency as part of a roughly $2.6 billion (yep, billion) light-rail project connecting downtown Seattle with the University of Washington and SEA-TAC airport. The voids were a result of running sand pockets in the otherwise stable clay units that were encountered by the tunnel boring machine or TBM. These voids migrated up like a chimney with one reaching the surface, almost 160-ft above the tunnel. This void was apparently 21-ft deep and opened up in a resident’s front yard and could have easily swallowed her up as she noticed it while gardening. The other voids were discovered at a depth of 20- to 65-ft below the ground surface. More after the break. (Illustration from Seattle Times)


Bump at the end of a bridge approach slab.
Journal Article Reviews

Scary: Things that go bump…at the end of the bridge

Bump at the end of a bridge approach slab.[Update 2008-11-03] The Link to the Journal’s homepage requires you to purchase the article. Too bad. Try the CDOT report instead I guess. [/Update]

First off, sorry for the cheesy Halloween tie-in. The other day I read an interesting paper in the Journal of the Transportation Research Record, No. 2045, of the Transportation Research Board (TRB).  The paper was titled: “Evaluation and Recommendations for Flowfill, and Mechanically Stabilized Earth Bridge Approaches.” I’ll post the full citation below. (Photo from FHWA NHI Soils and Foundation Course Slides, NHI Course No. 132012)

The authors describe the standard of practice for Colorado DOT (CDOT) projects for the last 16 years with regard to the construction of bridge approaches in an attempt to eliminate the problem with the “bump at the end of the bridge”. They discuss some of the common reasons for problems with approaches, and some possible solutions. Click through for more.



German town sinking after drilling operations

The historic town of Staufen in southwestern Germany on the western edge of the Black Forest is experiencing some rather unexpected downward movement these days. Several buildings, some of them historic, are experiencing cracking and distress and are still sinking at a rate of approximately 1mm per week. Investigations are underway, but everything seems to point towards drilling operations for geothermal energy which were conducted last fall. [Editor] More after the break…[/Editor]