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San Francisco Millennium Tower Has Settled 16 Inches
Misrepresents actual foundation geometry. Photos show deep excavation to ne
New FHWA Soil Nail Manual Addresses LRFD, Hollow Bars
Good evening from Barcelona, Spain. I am witting to you because of I am le
Engineering Geologists vs Geological Engineers vs Geotechnic
Geological engineer from Spain (looking for job smiley geoengineer.martin@gmail
A Whole Lotta Shakin' Goin' On: Center for Geotechnical Mode
Randy, While the UC Davis lab is impressive I believe the USACE Centrifuge
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New method for settlement-based helical pile design PDF Print E-mail
Written by Randy Post   
Tuesday, 05 November 2013 16:36
Deep Excavation Helical Pile Settlement Approach

Dimitrios at Deep Excavation posted an article last month about a new settlement method for helical piles that he is developing with Michael Perlow. The method is already showing promising results according to the article. It will ultimately be built into Deep Excavation's HelixPile software for analysis and design of helical piles, maybe it's already in there. [Source: Check out more at Deep Excavation. Image: Deep Excavation]

 
Video: Stephen Wright gives 2013 H.B. Seed Lecture on Slope Stability Calculations PDF Print E-mail
Written by Randy Post   
Monday, 21 October 2013 08:27

The 2013 H. Bolton Seed Lecture at Geo-Congress 2013 was given by Prof. Stephen Wright of UT Austin, a living geo-legend and one of the world's foremost experts on slope stability. His lecture is destined to be a classic, and was recently released on the Geo-Institute's YouTube channel. If you are a geotechnical engineer, make it a point to set aside the time to watch this lecture!

 
Geoengineer.org launches GeoSoftware Database PDF Print E-mail
Written by Randy Post   
Monday, 21 October 2013 01:25
Geoengineer.org GeoSoftware Database

Geoengineer.org has launched a new GeoSoftware directory, sure to be the go-to resource for our industry. The complete revamp of their previous directory will allow software vendors to provide news and video related to their products, and allow visitors to provide ratings and submit questions to the geotechnical software vendors. [Source: Check out the new GeoSoftware database at Geoengineer.org. Image: Geoengineer.org]

 
Guide for Conducting Forensic Investigations of Highway Pavements PDF Print E-mail
Written by Randy Post   
Sunday, 29 September 2013 23:30

TRB Guide for Conducting Forensic Investigations of Highway Pavements

TRB's National Cooperative Highway Research Program Report 747: Guide for Conducting Forensic Investigations of Highway Pavements explores a process for conducting forensic investigations of pavements that is designed to help understand the reasons behind premature failures or exceptionally good performance. The process also allows for the collection of data for use in developing or calibrating performance-prediction models.

The report includes example forms and checklists for use during the conduct of an investigation. These forms can be modified to suit the particular requirements and procedures for the agency. The example forms are included with the print version of the report in CD-ROM format. [Source: Download the Report and/or CD ISO from TRB. Image: TRB]

Last Updated on Monday, 30 September 2013 06:35
 
Video: Humes Segmental Shafts for Vertical Caisson Construction PDF Print E-mail
Written by Randy Post   
Monday, 23 September 2013 06:05

Last Updated on Monday, 23 September 2013 06:05
 
ADSC Technical Library Catalog PDF Print E-mail
Written by Randy Post   
Monday, 29 July 2013 23:35
ADSC Technical Library Catalog

The Association of Drilled Shaft Contractors or ADSC has a catalog of their technical library available through their website. ADSC has countless useful publications for drilled shaft designers, most of them very reasonably priced for members and non-members. [Source: ADSC. Image: ADSC]

 
TECCO Full-Scale Tilt Test PDF Print E-mail
Written by Randy Post   
Tuesday, 23 July 2013 06:45

This is a pretty neat video of Geobrugg AG Tecco slope stabilization mesh. They created a full-scale test setup with their TECCO mesh product restraining some knd of gravelly backfill. Then they tilted the entire setup up to 85 degrees and the system held. 

Last Updated on Tuesday, 23 July 2013 06:45
 
AASHTO 2013 Standard Specs for Sampling and Testing PDF Print E-mail
Written by Randy Post   
Thursday, 11 July 2013 13:49
Standard Specifications for Transportation Materials and Methods of Sampling and Testing, 33rd Edition

AASHTO's Standard Specifications for Transportation Materials and Methods of Sampling and Testing, 33rd Edition and AASHTO Provisional Standards, 2013 Edition are now available for pre-order, delivery will start later this month. The 33rd Edition of the Materials Book contains 400 materials specifications and test methods commonly used in the construction of highway facilities, including 60 revised and 7 new specifications and test methods. The specifications have been developed and maintained by transportation departments through participation in AASHTO's Subcommittee on Materials. [Source: AASHTO Bookstore. Image: AASHTO]

 
Detection of Sinkholes or Anomalies Using Full Seismic Wave Fields PDF Print E-mail
Written by Randy Post   
Thursday, 11 July 2013 13:38

Michael McVay and Khiem Tran of the University of Florida have produced a report for the Florida DOT on the detection of sinkholes using full-field seismic waves. Here is the abstract:

This research presents an application of two-dimensional (2-D) time-domain waveform tomography for detection of embedded sinkholes and anomalies. The measured seismic surface wave fields were inverted using a full waveform inversion (FWI) technique, based on a finite-difference solution of 2-D elastic wave equations and Gauss–Newton inversion method. The key advantage of this approach was the ability to generate all possible wave propagation modes of seismic wave fields (body waves and Rayleigh waves) that were then compared with measured surface data to infer complex subsurface properties. Both the pressure wave (P-wave) and shear wave (S-wave) velocities were inverted independently and simultaneously. The FWI was applied to two synthetic and four real experimental data sets. The synthetic inversion results showed that the inversion was capable of detecting layering (e.g., strong over weak), and anomalies; in addition, the initial input velocity profile for the inversion was straightforward (i.e., linearly increasing with depth). The developed FWI algorithm could run on raw collected data with a minimum manual effort (no picking of first-arrival travel times). The inversion results of real data sets showed that the waveform analysis was able to delineate: 1) an embedded concrete culvert; 2) extent of multiple existing sinkholes/chimneys; and 3) a complex profile with an embedded void (unknown at time of data collection) and highly variable bedrock both laterally and vertically. Independent invasive testing (standard penetration test, SPT, and cone penetration testing, CPT) was conducted to verify the seismic test results. Finally, for the cases presented, the 2-D full waveform inversion was found computationally practical, i.e., the results were achieved in 2-4 hours of computer time on a standard laptop computer.
[Source: Download the report through the TRB]

 
Cellular Concrete: Filling the Void PDF Print E-mail
Written by Randy Post   
Monday, 08 July 2013 23:12
Cellular concrete being flowed into pipeline trench

An article in TBM magazine provides a nice overview of cellular concrete technology. I never knew this (although it makes sense) but the material was used primarily as a lightweight floor leveling product for high-rise construction when it first came to the US in the 1950s. The article finishes with an overview of why cellular concrete is well-suited for grouting applications associated with tunneling and pipeline work. [Source: Read the full article at Tunnel Business Magazine via Cell-Crete Newsletter. Image: Tunnel Boring Magazine]

 
Design Guidelines for Horizontal Drains Used for Slope Stabilization PDF Print E-mail
Written by Randy Post   
Sunday, 16 June 2013 23:37
Horizontal drains used for slope stabilization

The Washington State Department of Transportation has released a report that provides a reference for geotechnical engineers and hydrogeologists on designing horizontal drainage systems to improve slope stability. Here's the report abstract:

The presence of water is one of the most critical factors contributing to the instability of hillslopes. A common solution to stabilize hillslopes is installation of horizontal drains to decrease the elevation of the water table surface. Lowering the water table dries a large portion of the hillslope which increases the shear strength of the oil, thereby decreasing the probability of slope failure. The purpose of this manual is to provide a single comprehensive reference for geotechnical engineers and hydrogeologists on designing horizontal drainage systems to improve slope stability. Guidelines are provided for translational and rotational failure and consider fractured systems. Basics of hydrogeologic and geotechnical terminology, site characterization and conceptualization, groundwater modeling techniques and template projects help to guide the user with respect to identifying important parameters to drainage design. An iterative approach is presented for determining the minimum drain construction to lower water levels enough to keep the factor of safety (FOS) greater than 1.2.
[Source: Download the entire WSDOT Report by way of TRB. Image: WSDOT via TRB]

 
Using the Existing Pavement In-Place and Achieving Long Life PDF Print E-mail
Written by Randy Post   
Monday, 10 June 2013 23:56

Several types of concrete overlays

TRB's second Strategic Highway Research Program (SHRP 2) Renewal Project R23 has released a prepublication, non-edited version of a report titled Using the Existing Pavement In-Place and Achieving Long Life that describes a procedure for identifying when existing pavements can be used in place as part of the rehabilitation solution and the methods necessary to incorporate the original material into the new pavement structure while achieving long life.

In addition to the report, Renewal Project R23 also developed an interactive computer software program that helps users through the decision process. The software also provides all of the resource documentation related to the project. [Source: TRB. Image: TRB/SHRP2]

Last Updated on Tuesday, 11 June 2013 07:00
 
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