Geotech leaders: Dots Oyenuga of ASC and his lifetime in tunneling
In the second of a new series of interviews with some of the world’s leading lights in tunnel monitoring, we speak to Dots Oyenuga, founder and owner of tunnel monitoring specialist Analysis & Solutions Consultants.
Dots Oyenuga’s passion for engineering stems from a train journey in France. Riding the high-speed TGV, he was struck by the train’s ability to hurtle along the track so smoothly that even a filled cup would not spill a drop. That day set him on the path to becoming one of the foremost metro engineering specialists in the world.
After taking a Masters’ Degree at George Washington University in the US, he earned a doctorate in geotechnical engineering from the Institut National Polytechnique de Lorraine in France. In the 1980s, he did his doctoral research on deep foundations and the relationship between steel piles and sand. Oyenuga founded Analysis & Solutions Consultants (ASC) in 2001.
This California-based design and construction consulting firm has provided tunnel monitoring support for all kinds of tunnelling projects, with a particular focus on infrastructure and transportation, ever since. Currently, ASC is providing tunnel monitoring services on three enormous urban tunnelling projects, with a total budget of more than USD$3.8 billion, on the Los Angeles Metro’s Purple Line extension into Beverly Hills.
Oyenuga says winning those three contracts in a row is one of his proudest achievements. But it has not all been plain sailing. When Nigeria-born Oyenuga entered the field 40 years ago, engineers were mostly white and male. Even today, data from the National Science Foundation shows only 4.3% of engineers identify as black. As a result, Oyenuga has had to overcome the prejudice faced by many people of colour in the industry.
We were honoured to speak to him about his long and successful career, delve into his pioneering experience in tunnel construction monitoring and gain some insights into the challenges of tunnelling.
What inspired you to specialize in tunnel monitoring, and where has that path led you?
What are the main challenges you face in tunnel monitoring projects these days?
What have been the benefits of bringing wireless technologies to the tunnel monitoring?
What trends do you see developing in wireless tunnel monitoring technologies?
Which tunnel monitoring project has impressed you most in all your years in the industry, and why?
What inspired you to specialise in tunnel monitoring, and where has that path led you?
Dots Oyenuga: I lived in France for five years. When I first took the TGV, which is the French high-speed train, I was impressed because I had a full glass of water on my table that didn’t spill, despite the train going close to 200 miles an hour. I thought that was a great feat of engineering, like the French subway tunnels and metro systems which I was also exposed to.
Ever since then, I’ve enjoyed working on tunnels. And I’ve been involved in close to 20 tunnelling projects, including—in the Bay Area—the Dublin Pleasanton extensions and the Transbay Tube Seismic Retrofit project. I also worked on the H-3 tunnels in Hawaii. I wrote the road tunnel design guidelines for the Federal Highway Administration, which is now used worldwide for the design of tunnels and also sold around the world by the US Department of Commerce.
I decided to go into structural and geotechnical instrumentation because the landscape for engineering design was choked up by larger firms. Only the crumbs were left. Instrumentation was pretty much virgin territory, so I staked my claim there and started my company about 20 years ago. We specialized in monitoring tunnel construction, providing all the tools necessary.
We are the first in the US to use an integrated, automated wireless data acquisition system to monitor urban tunnel construction projects. We dispense with all the legacy systems. Everything is automated, everything is wireless. And we’ve had a lot of success with it. We’re currently monitoring 10 miles of tunnel construction in Los Angeles in real time. We have close to 10,000 sensors that we maintain for that task. That number will probably increase to around 17,000. That’s quite a bit of monitoring.
We’re also providing critical surveys for about 700 buildings, and real-time construction noise and vibration monitoring and control. It’s quite a task and we’re very fortunate to be in this position.
What are the main challenges you face in tunnel construction monitoring projects these days?
It depends on the delivery methods that are being utilized. In design-bid-build scenarios, where the project documents are put out to bid as opposed to when the bid goes out early in the design, the contractor is responsible for finalizing the design and constructing the project. Also, you could have a progressive design build, in which the owner of the project works with the contractor and they jointly come up with the final documents. Then the contractor will go ahead with the construction.
Everything is locked up in that scenario, and there’s no change allowed. The contractor is invested in the design process early. There’s also the situation where you might have the underground environment as a separate contract from the tunnel. We sometimes have a lot of potential stakeholders that we interface with, including in the city, the county, commercial property owners and residential property owners.
Because we interface with all these stakeholders, in most instances we prefer to use wireless technology. We integrate automated data acquisition systems in the wireless system. The installation of monitors and monitoring of the tunnelling has to be done with minimal disruption. As a result, we prefer to have wireless systems to avoid having to lay lots of cables that would disrupt traffic.
What have been the benefits of bringing wireless technologies to tunnel construction monitoring?
The main benefit is dispensing with cabling as much as possible. In some instances, we still have cables, but it’s minimal, so we don’t break up the roadway, disrupt the flow of traffic and block pedestrians’ right of way. It’s been very helpful from that perspective, but I think the industry is slow to adopt technology. Other industries have embraced technology like automation, but our industry is still lagging in this regards.
I think that’s primarily because of the litigious nature of contracting and the industry in the US.
What trends do you see developing in wireless tunnel construction monitoring technologies?
Right now, we’re focused on the micro level, in the sense that we have all these little sensors and we monitor all the sensors using data loggers. But I think automated data collection will grow. So, we could have fewer sensors and have them move from one point to another and collect data that way. I think another change is using the macro level as opposed to micro level.
There’s technology out there called InSAR [interferometric synthetic-aperture radar] where we can use satellites and come up with pre-existing trends and settlement patterns prior to construction. During construction, we can measure at a macro level, and then zero in on more problematic areas and take more detailed measurements from legacy systems. I think that’s probably where we’re headed with this.
You could have settlement maps long before we start to contemplate having construction in those areas. Anyone involved in construction could dial up historic data and use those trends to map movements.
Which tunnel construction monitoring project has impressed you most in all your years in the industry, and why?
I think it probably will be the projects that we have in Los Angeles. These are really signature projects. We’re constructing a subway system to Beverly Hills and other critical infrastructure, and we went under the 405 Freeway, where we had continuous mining. We’ve brought a lot of technologies to bear on that. We’re doing reflector-less monitoring where we’re not putting prism targets on structures but, instead, we monitor remotely.
We’re pushing the envelope and coming up with new applications for technologies—and it’s been a lot of fun, and a real boost to our confidence. I think we ultimately want to become the best organization for instrumentation in the US for tunnel construction. And I think we’re pretty much on our way.
Renaissance man Dots Oyenuga is living proof of the value of diversity in geotechnical engineering and instrumentation. Using wireless remote monitoring technologies, his experience and knowledge are helping to safeguard the progress of some of the most important subsurface projects in North America.