Category Archives: Load Testing

DBA on successful St. Louis Bridge team

BridgeImage2009_MS STL mrb-logo

DBA is on the successful team that was awarded the contract for the new Mississippi River Bridge in St. Louis, Missouri.  The project is a joint project of MoDOT/IDOT with MoDOT being the lead agency.  HNTB is the lead bridge designer for the new cable-stayed bridge carrying I-70 over the river.  The bridge is one part of a larger project that also includes the Missouri North I-70 Interchange, the Illinois I-70 Connection, and the Illinois Tri-level Exchange.

From the project web site:

The $640 million Mississippi River Bridge project is proceeding through design, with construction scheduled to start in early 2010. The new Mississippi River Bridge is the first bridge built connecting downtown St. Louis and southwestern Illinois in more than 40 years. Currently, the only urban interstate bridge between Illinois and Missouri is the Poplar Street Bridge, known locally as the PSB. The PSB is one of two bridges in the United States that carry three interstates. By relocating one interstate (I-70) from the Poplar Street Bridge to the new Mississippi River Bridge, drivers will experience less congestion, fewer crashes and less unnecessary fuel use.

The new Mississippi River Bridge will be a 1,500 foot cable-stayed bridge across the Mississippi River between Metro East and St. Louis, Missouri. The bridge is two lanes in each direction, but is wide enough to be restriped for three lanes in each direction if traffic volumes warrant and additional funding is secured. In addition, the bridge project includes approaches on the Illinois and Missouri sides to get traffic to the bridge.

The wining contractor team is Massman/Traylor Brothers/Alberici Constructors.  DBA’s role was to help prepare an alternate concept for the drilled shaft foundation design which will include load test measurements.  We anticipate construction to begin in March with load test shaft.

An overview of the bridge is here.  The press release for the award of the main bridge is here.

logo-massman logo-traylor alberici

Characterization of Loess for Deep Foundations

loess map

 

I have added a recent paper that Dan and Steve contributed to concerning loess that is in the November, 2009 issue of the DFI Journal.  The paper describes the results of site investigation and laboratory tests at a site in Kansas with loess deposits.  The effectiveness of various correlations between field and laboratory tests and design properties are evaluated.  Steve is currently working on the follow-up paper that evaluates lateral load tests of drilled shafts at the site.

Parson, R.L., Johnson, R.M., Brown, D.A., Dapp, S.D., and Brennan, J.J., 2009. “Characterization of Loess for Deep Foundations”, DFI Journal Volume 3, No. 2, November 2009, Deep Foundations Institute, pp14-24.

Video: Lateral Load Test with Statnamic Device

One area of work we are frequently involved in is data analysis and evaluation of lateral load tests performed by the Statnamic testing device (learn more at the website of Applied Foundation Testing).  The mathematics involved in the data reduction can be quite formidable as you interpret the dynamic load-response to an equivalent static load-response.  Regardless of the math behind it, watching a test can be pretty cool.  It is a whole lot of work for a brief moment of load, but in some situations it can be more economical than a traditional load test. 

The video below is from a test on 170-foot long, 32-inch outside diameter steel pipe pile with 0.75"-inch wall thickness.  The pile was filled with concrete that included an instrumented rebar cage.

Enjoy!