I spent a very pleasant Saturday morning with the GeoStabilization crew as they wrapped up shotcreting the face of their Lower San Antonio Road landslide repair while I ran the nail capacity performance test. The site is surprisingly far east to still be in Santa Clara County, past Lick Observatory by almost an hour on a beautifully scenic winding road. The test setup is pretty simple, as you can see above, and the loads are modest enough that simple cribbing on soil provides enough reaction force. We’re really enjoying this on-call collaboration with GSI and I’m angling for a way that I can cover the next testing assignment.
Category Archives: Geohazards
This morning the Corps of Engineer’s was finally overwhelmed and lost control of the flow rates out of Addicks and Barker Dams, losing the last controls over theBuffalo Bayou water level as it flows through the middle of downtown Houston. Dams are the most useful and also the most dangerous infrastructure in any community, and losing control of the outflow rate represents a significant escalation in the flood severity. Flood level management is an intricate dance of competing compromises, where retaining water behind the dam makes flooding worse upstream and releasing water makes things more severe downstream. The US Army Corps of Engineers does an excellent job navigating these difficult choices, and the disaster is always worse when the Corps loses their ability to influence the drainage patterns. Hopefully the impacted areas downstream have already been evacuated, and the rising waters spread slowly enough that first responders can help people out of harms way.
The focus of the regional emergency response system is, quite correctly, on assuring people’s safety and well being. Our work at Atlas includes participating in emergency planning efforts and also incident recovery efforts, but the actual emergency management is not part of our core expertise. For now we watch and wait, and hope that the available resources and management are enough to protect the people who are in harms way.
There’s a possibility that engineers at Atlas may assist with damage assessment and field-engineered repairs at flooded petroleum facilities along the Gulf coast. Until the flooding abates, though, there’s little that we can do besides monitor the situation and make plans for a rapid and efficient deployment. When the rain stops and the waters recede, that’s when it’ll be time for the engineers to go to work restoring safe conditions at dams, highways and bridges, industrial facilities, and other essential elements that make Houston a thriving metropolis.
I’ve had a very productive week here on Majuro, the principal island in the Republic of the Marshall Islands. Our longtime collaborator Lyon Associates invited us to join their team for a Sea Grant project focused on developing a suite of best practices for shoreline protection around the Marshalls, where land uses range from dense urban in downtown Uliga to rural in Laura, at the other end of the long island.
Really, this is a capacity building exercise focused on increasing efficiency and reliability of small-scale projects implemented by homeowners, who are getting specialty advice from contractors and regulators about appropriate and affordable shoreline protection. There are a lot of stakeholders with different interests and a huge range of site and wave loading conditions, the perfect conditions for high-quality consulting. It’s gratifying to be working on such an important project.
I’ve been struck by how much of urban Majuro is already protected by well-built shoreline protection. Keeping tide and waves out of dwellings and off of city streets is plainly an important priority that lays claim to a significant fraction of limited local resources. And while many lots have stabilized shoreline, some have not yet been addressed. From infill seawalls (below) to increased setbacks and soft beach-sand berms, we’re hopeful that we can develop a useful set of best practices that facilitate safe and comfortable life on this low-lying atoll.
A lot of you have heard me hold forth about how unpredictable events wield disproportionate influence over our lives, especially our careers. The circumstances that led to Atlas Geotechnical’s founding are a classic example of working really hard to be in the right place at the right time for an unpredictable opportunity.
We experienced another unlikely coincidence this past weekend with the occurrence of a M5.8 earthquake northeast of Oklahoma City. This is another incident thought to be caused by injecting produced water into deep formations, changing the state of stress and causing the earth’s crust to make slight adjustments, shifts that we experience as earthquakes.
The coincidence is that for the past month Atlas has been working (through our good friends at PEMY Consulting) on installing an accelerograph at a petroleum facility 50 km south of the epicenter. The accelerograph was just ordered last week, so we didn’t get any data from the event, but even without measurements the earthquake assured our client that their monitoring and preparedness efforts are valuable. It’s gratifying to be helping a client address a risk that actually occurs in the course of the project, especially when there’s no actual damage.
The project also includes developing a procedure for responding to earthquakes systemwide, including performing inspections to assure that (typically older) equipment was not displaced by the shaking. The earthquake probably caused peak ground accelerations of 6% to 8% of gravity at our accelerograph site, not enough to cause any real risk of damage but certainly enough for the control room staff to feel the shaking and to understand the need for a prompt visual inspection.
It seems that earthquake risk management is becoming more important in areas that were not previously known for seismicity. And through a combination of good luck and engineering enthusiasm, Atlas is again ideally positioned to help our good customers address this new (to them) operational risk.