Areas surrounding the access pit being excavated to rescue the stalled Bertha TBM have experienced settlement as much as 1 to almost 1.5 inches according to a draft figure released by WSDOT on December 11, 2014. The aging and seismically deficient Viaduct itself has experienced 1 inch of settlement as well. Structural engineers have inspected it as well as numerous buildings in the area and have not found structural damage. The settlement is thought to be related to the dewatering associated with the access pit construction. The excavation was within 3 feet of the bottom when the settlement issues were first announced on December 5, and WSDOT has since allowed the contractor to complete the excavation. [Source: Read more information in the update provided by the WSDOT Alaskan Way Viaduct Replacement Project team. Image: WSDOT]
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San Francisco Millennium Tower Has Settled 16 Inches
The residential high-rise Millennium Tower in San Francisco has settled a total of 16 inches since opening, 2 inches deferentially. A spokesman for the tower owner blames the settlement on the excavation next door for the Transbay Transit Center, a $2.4 billion dollar project being constructed 60 feet underground.
However, the Transbay Joint Powers Authority (Transbay) hired geotechnical firm Arup in 2010. Their initial report indicated that the tower had already settled 10 inches by the time excavation began for the Transit center. Arup seems to have been tasked with design, installation, and perhaps monitoring of a geotechnical monitoring program, some information on the scope is available in a 2012 presentation given by Arup available on the Transbay website.
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Deleware Forced to Redesign Unfinished Bridge Because of Consolidation Issues
[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.