A team from Northeastern University has a very interesting van used for quantitatively assessing pavement condition using a variety of sensors. They use cameras, laser profilers, accelerometers on axles, pressure sensors in the tires, microphones, and even ground penetrating radar. The researchers reportedly characterized pavement condition of 150 miles of road in 4 days in Beverly, Massachussets, a task that took public employees about 1 year the last time it was performed, in 2010. The cost of the survey was around $25,000. The technology is expected to be commercialized this month. [Source: The Boston Globe. Image: Boston Globe]
Not too much to say about this, but check out the photo. The entire westbound portion of US Highway 52 near the Ohio River was closed last week as a house-sized boulder and other rockfall debris landed on the roadway. Crews anticipated it would take several days to clear the material and reopen the road. [Source: WLWT News via USGS Landslide Events. Image: Kentucky Transportation Cabinet via WLWT]
SALT LAKE CITY, April 13, 2015 /PRNewswire/ -- Boart Longyear (www.BoartLongyear.com), the world's leading provider of integrated drilling services and drilling products, is proud to introduce the LS™250 MiniSonic™, a compact rig suitable for a wide variety of environmental, geotechnical, water and mining projects.
Capable of drilling to depths of up to 250 feet (78m) when used with 4.75 inch (121mm) casing, the wide 600mm rubber tracks provide low ground pressure (.28 bar/4psi) and make it perfect for jobs in the most sensitive and fragile terrains. Plus, its smaller footprint makes it appropriate for projects with small drill pads, environmentally sensitive areas or hard-to-reach sites and requires less support equipment – making it a low-cost solution for a variety of mining, environmental, geotechnical and infrastructure drilling projects.
[Editor] Click through for the rest of the press release from Boart Longyear. [/Editor]
Since March of 2003, the FHWA’s Geotechnical Engineering Circular Number 7 (GEC No. 7) has been the standard reference document for design and construction of soil nail retaining walls in roadway applications, and really in all applications. The FHWA has released an updated version of this manual as of February of 2015. This new version is still called GEC No. 7, but now titled “Soil Nail Walls Reference Manual.” You can download the document from the FHWA’s Geotechnical Engineering website.
I am still in the process of working through the manual, but one of the major changes is the addition of the implementation of the Load and Resistance Factor Design (LRFD) platform. This will have an implication on all future soil nail walls for roadway projects.
The manual also appears to have removed example problems solved using SNAILZ software (by CalTrans) in favor of the FHWA’s own Soil Nail Analysis Program (SNAP) 2 software. I guess we’re going to have to get familiar with that software as well. I’m strongly considering looking into SNAIL Plus by DeepExcav, a commercial product. I’ve seen demos before, and have been very impressed.
Finally, I was very curious to see what they would say about hollow bar soil nails. They review some of the work done in the last 5 years or so done by the FHWA and ADSC. If I understood correctly, it appears that they are saying that because of the uncertainties regarding damage to corrosion protection during installation, they are still not recommending hollow bar nails for roadway applications, except if the ground conditions are non-aggressive and if you use sacrificial steel. I suppose that at least opens the door to this technology for collapsing ground situations.
There was a significant slope failure at the Yeager Airport near Charleston, West Virginia last week. A 2005 project to create an Engineered Material Arresting System (EMAS) at the end of the runway required a massive reinforced soil structure fill slope over 200 feet high since the airport was constructed on top of a hill. According to a presentation published by the geogrid manufacturer, this project was the tallest known geosynthetic reinforced 1:1 fill slope in North America (as of 2010). The slope failure follows a period of significant snow melt and rainfall. It is a deep-seated failure, apparently a compound failure that cuts through the reinforcement based on one of the photos available in the Charleston Daily Mail article cited in the article at the Landslide Blog. I'm sure there will be much more information about this massive failure in the coming months.
National Driller has a nice interview with the 2015 Terzaghi Lecturer, Donald Bruce, President of Geosystems. Bruce, best known for his expertise in grouting, will deliver his Terzaghi Lecture at this week's IFCEE conference in San Antonio. [Source: Read the interview at National Driller. Image: National Driller]
Advanced Construction Technology Services (ACTS) has contracts for geotechnical work for 3 lines of the proposed subway in Doha, Qatar. They have completed investigations for approximately 95 km of line and 51 stations and are currently working on the recommendations for track designers. The contract for the these services is worth approximately $1.37 million. [Source: Trade Arabia. Image: Trade Arabia]
EarthScience Information Systems (ESCIS) is pleased to announce the release of the Shoalhaven City Council Aqua Data website, a branding of the ESdat Public Portal.
Aqua Data is a web-portal providing greatly enhanced community access to the results of water quality monitoring completed by Shoalhaven City Council (SCC). Aqua Data is the public interface of a detailed system designed to streamline the way SCC manage and share environmental data.
Aqua Data is accessed via a link on the Shoalhaven City Council web site directing users to the Aqua Data home page
[Editor]Click through for the rest of the press release and a link to go check out the Aqua Data interface! [/Editor]
WSDOT reported that Bertha has slowly began moving again. It must tunnel through 20 feet of unreinforced concrete with its broken seal to break through into the rescue shaft. Once that happens, the repairs to her cutterhead can commence. The Seattle Tunnel Partners predict Bertha will overheat, as she did before stopping for repairs. If that occurs, they will stop tunneling to wait for the machine to cool before continuing. STP crews also chipped away at a Bertha-sized cut-out in the access shaft to make for a cleaner breakthrough. See video below. [Source: WSDOT and WSDOT YouTube Channel. Image: YouTube]
National Driller magazine recently republished a paper by authors from GRL Engineers Inc. and Pile Dynamics Inc. (PDI) describing a demonstration project for the Texas Department of Transportation involving thermal integrity profiling (TIP) of soil nails. TIP involves using the thermal energy created by curing concrete to determine the shape of a grout or concrete body and the position of reinforcement within a grouted or concreted hole. It has been used successfully for QC of drilled shafts and auger cast piles. It can be performed in open access ports by lowering a thermal probe down the hole, or by attaching thermal wire cables to the reinforcement with sensors spaced every 6 inches. This study used the thermal wire cables attached to two soil nail bars grouted into 6 inch diameter holes. The first nail had no deliberate defects, the second had two intentional soil inclusions attached to the bar prior to grouting. The TIP successfully identified the anomalies and it appears that the method shows potential for QC of the shape and diameter of a grout body around a soil nail. [Source: Read the article at National Driller. Image: National Driller]
The Alaskan Way Viaduct tunneling project was in the news late last year when settlement of the Viaduct was reported during the dewatering efforts for the Bertha TBM rescue shaft. A recent post by WSDOT makes it clear that the settlement of the viaduct has been a problem for many years before the start of construction. The most recent round of monitoring by WSDOT began in 2001 after the completion of repairs to the the Viaduct following the Nisqually Earthquake. By 2006, a total of 4 3/4 inches of settlement had been recorded at one location. It appears that the rate of settlement is on the order of about 1/8 inch to 1/4 inch per year. I am sure the dewatering around the access pit didn't help the problem, but it looks like it didn't create it by itself either. This information just underscores the importance of the tunnel project to replace this aging structure. [Source: WSDOT Alaskan Way Viaduct. Image: WSDOT and STP via KPLU]
Redditch 30th Jan 2015 - The new release of HoleBASE SI includes ‘scheduling tools’ that allow engineers to electronically schedule geotechnical or environmental testing. This major breakthrough is likely to transform the way consultants and laboratories communicate with each other over the coming months.
The new improvements also provide a glimpse of how well integrated customers and laboratories can be with the first UK wide implementation of a web service connection to ALcontrol’s @mis online laboratory data management system. . This unique development allows customers to schedule testing directly into the @mis system using data and tools inside of HoleBASE SI and then be notified within HoleBASE SI when the testing is completed.
[Editor] Click through for the rest of the press release from GeoPrac Sponsor, Keynetix [/Editor]