settlement – Page 4 – GeoPrac.net

Geofoam used on Pacific Street Bridge Project in Omaha, Nebraska

Geofoam Offers Performance and Efficiency, Streamlining Nebraska Traffic

August 25, 2009 Nico Sutmoller 3

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]

[…]

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

May 7, 2009 rockman Comments Off

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.

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

October 31, 2008 rockman Comments Off

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

February 25, 2008 Wolfgang Fritz 2

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]

[…]

Deleware Forced to Redesign Unfinished Bridge Because of Consolidation Issues

January 25, 2008 rockman Comments Off

[Update 2/10/08] Updated the name of the bridge. [/Update]

DelDOT is putting the new Indian River Bridge over out to bid. The current bridge is said to be in danger of failing between 2008 and 2012 according to the Army Corps of Engineers, seems to be related to scour. From what I hear, the tidal currents at that inlet being spanned over are tremendous, with water velocities on the order of 35 mph.

In 2005, Mactec, a geotechnical firm, provided a geotechnical report and associated recommendations to DelDOT for how to construct the 45-ft high approach embankments for a 1,400-ft long bridge in light of a 60-ft clay layer (sounds like pre-loading). However, the embankments are not settling as Mactec predicted (not sure if its more or less, probably less meaning slower) and are "shifting laterally" (squeezing?) so the DOT is going with a longer bridge to span the problem soil. More after the break.

[…]

Jefferson Memorial’s Signs of Sinking Raise Fresh Alarms

July 15, 2007 rockman Comments Off

The National Park Service is carefully monitoring a settlement problem at the Jefferson Memorial in Washington D.C. The geotechnical problem area is a seawall that borders the Memorial’s plaza that seems to be settling away from the plaza. Read on for more info. [Photo by esev]

[…]