Tag Archives: Old Friends June 2012

I had a really excellent time last week attending the Dispute Resolution Board Foundation conference and training in Seattle. The DRBF (http://www.drb.org/) is a small, sincere organization  that promotes dispute avoidance and resolution on construction projects using the proven Dispute Resolution Board (DRB) method. Having participated in much larger, formal, and bureaucratic standards organizations, the DRBF conference was refreshing in their pragmatic approach to accomplishing the group’s mission. Training was provided by founding members, the attendee were a veritable “who’s who” of construction in the Pacific Northwest, and the excellent interactive format made the training quite effective.

At 47 years old, and with 24 years professional experience, I was the second-youngest person attending the meeting (one of the founding members brought his son,. an accomplished construction manager.) The group has recognized a need for younger members and is in the early stages, it seems, of taking action toa ssure that the organization manes a successful transition when the founding members are ready to reduce their involvement.

As an added bonus, a neighbor of ours back in Lake Oswego was there for part of the conference. Two goals for our move back to the Mainland were to reconnect with a broader professional community, so I could attend events like the DRBF conference, and to reconnect with old friends. It was particularly satisfying that both happened at the same event.


Longtime collaborator Steve Mumma called the other day looking for geotechnical support on an interesting impact barrier project.  Steve manages Geobrugg North America’s Security Division, though we know him from when he was an extremely helpful resource for rockfall protection projects.  It’s always great to hear from old friends, and old friends with interesting geomechanical problems are the best.

Geobrugg is supplying the debris barrier for a new Formula 1 racetrack near Austin, TX. You’ve all seen these: wire mesh and horizontal cables supported by poles that catch pieces and parts of crashing F-1 cars moving as fast as 240 kph. The picture above, which I borrowed from the project website, shows the fence in the background. Performance expectations for such a barrier are quite different than for most structures: huge deformations and partial collapse are a necessary part of proper barrier function. The direction and magnitude of forces transmitted by the yielding, collapsing posts into their foundations change wildly during the incident, further complicating the geotechnical design.

It is widely known that conventional geotechnical computations underestimate dynamic foundation capacity, although this fact seems not to be very well understood by most practicing geotechnical engineers. The difference between theoretical and actual foundation capacity has its roots in the simple Mohr-Coulomb constitutive model intrinsic in most  geotechnical computations. Assuming linear elastic behavior up to the instant of failure excludes energy consumed by volumetric strain as the failure condition develops. Behavior that would never be allowed to occur on a conventional footing is actually an important attribute of dynamic loading on a properly functioning debris barrier.

We did a couple of days worth of computations, enough to get the correct outcome based on technical merit, without having to resort to uncommon constitutive models that would have led, inexorably, to time domain numerical modeling.  While that type of work is like candy to the crew here at Atlas, it wasn’t necessary to achieve a positive outcome for the Formula 1 racetrack project.  We are grateful for the chance to reconnect with Steve, for the confidence that Geobrugg North America placed in Atlas Geotechnical when faced with an unexpected issue, and for the chance to do challenging work in support of interesting infrastructure projects.


Atlas Geotechnical is very pleased to be part of the research team that the California Strong Motion Instrumentation Program (CSMIP) selected for a 2012 Data Interpretation Project focussed on the behavior of port structures during long duration seismic shaking.  The award is mainly because Dr. Steve Dickenson is our team’s principal investigator. Steve has long been a recognized leader in port seismic design, and his practical approach to validating the numerical model used by the engineers at Halcrow  was likely the winning feature of our proposal.

A research project like this is an excellent example of the diversity that Atlas Geotechnical has been working to achieve. In addition to the chance to work with Steve and with Halcrow, this project offers a chance to meet the port engineers at Oakland, Los Angeles, and Long Beach, and also to present to the CSMIP committee a couple of times in the course of completing the research. The work kicks off in early July with visits to the ports to collect reports and as-built data.