Monday, December 10, 2012
Posted by Alistair Steele
There's a troubling contradiction in that B.M. Ross report on the Highway 174 sink hole. (See what happens when you release important documents late on a Friday? Journalists who were forced to rush their stories and limit their questions to "high level" have the whole weekend to go back for a second look at the details.)
Among the consultant's findings:
- Based on the August, 2011 CCTV video alone, "it would not be possible to determine when the pipe might collapse."
- "...the video image does not indicate well that almost two square metres of material had disappeared from the side of the pipe."
- The video showed the pipe was still "circular...considering the condition of the pipe an emergency was not warranted" despite the severe corrosion that was clearly visible on the video.
B.M Ross describes the pipe as a "soil metal structure," which is to say the soil and the pipe act as two, interdependent parts of the same machine. The forces created by the loads above the pipe (such as road surface and traffic) are transferred to the surrounding soil. The stability of the entire structure depends on something called "ring compression," or the way the circular pipe interacts with the soil around it. "Loss of soil results in loss of stability. When combined with the loss of pipe strength through corrosion, there is definite potential for failure."
Anyone who's seen the CCTV footage has also seen the large voids in the clay behind the holes in the pipe. In fact, B.M. Ross suggests by the time the collapse occurred one year after the video was taken, those voids were even larger: "Following the failure, one of the Contractor's personnel who was working in the structure commented that the eroded pockets behind the pipe appeared to be larger than indicated by the image in the 2011 CCTV inspection."
B.M Ross draws the following conclusions:
- "Consideration should have been given to ensuring that the soil erosion outside the pipe was not a concern and that further erosion did not occur,"
- "The significance of the deterioration in terms of the structural integrity of the pipe was not known. The potential for soil erosion to continue and further weaken the structure was apparently not understood.
- "Those who viewed the video did not appreciate the importance of protecting the native soil on the exterior of the pipe from erosion."
- "We believe that individuals with experience in design and/or inspection of larger steel structures would have reacted differently."
So here we have a video which was reviewed by staff in three different offices the very day it was recorded. They clearly recognized there was an issue, because the very next day the City changed the work order from a routine headwall replacement to a complete re-lining. (Why it took the contractor a little over a year to get started is another question that deserved to be asked -- and answered -- last week.) But did they recognize the right issue? It seems none of the City's professionals understood what I found out showing the video to the first engineering professor who would talk to me: Soil erosion leads to structural failure, sooner rather than later.
So while B.M. Ross notes on one hand that the timing of the collapse couldn't have been predicted by looking at those rusted gaps, he also concludes "although those who saw the CCTV video recognized the need for rehabilitation, they did not translate what they observed into potential instability that needed to be immediately investigated further and acted on." So it's not so much what that video didn't show; it's what was shown, but wasn't seen.
Friday, December 7, 2012
Posted by Alistair Steele
I don't know whether Dalton McGuinty made an honest error, or intentionally embellished the truth when he said this about Ottawa's LRT mega-project earlier this week:
"About 80 per cent of the jobs generated from the project will be local. That's about 20-thousand jobs."
There's quite a bit wrong with that statement. First, other officials, including the mayor, claimed later that 80 per cent of the jobs will be local. Not that 80 per cent of the job equals 20-thousand. But there was more than a mere mathematical mix-up in the premier's statement. Here's the City's official explanation of that 20-thousand figure:
"This number, which was originally presented in the 2009 LRT Business case, was generated using a Statistics Canada input-output multiplier formula relating to the transportation sector for the investment proposed for the OLRT/Confederation Line project. The output provided estimates of the direct and indirect employment impacts of the capital investment in Ottawa.
Rideau Transit Group has provided a more detailed accounting of direct job estimates. It is anticipated that the construction of the Confederation Line will generate over 3,200 direct person-years of trades' employment in the Ottawa area. Skills employed will encompass the full spectrum of construction trades including road building, civil works, tunnelling, track work, and bridge work; structural, architectural, electrical and mechanical work. Expertise in systems and communications will also be required. Highly skilled technical staff will be hired, leading to an additional 700 person years of employment in Ottawa. Also, 375 person-years of engineering employment will be created. As referenced above, these direct jobs will create a multiplier effect in the local economy which is anticipated to generate over 20,000 people years of employment in indirect or induced impact over the construction period."
So it's not really 20-thousand new jobs, is it? It's 20-thousand "person-years." That's the same as one year of employment each for 20-thousand people. Or longer-term jobs -- maybe even full-time, permanent ones -- for far fewer folks. That seems to be the vision for some of the 200 or so skilled workers who will assemble the trains at that new "Centre for Excellence" on Belfast Road. Rideau Transit Group says the plan is to turn them into maintenance workers after the Confederation Line is finished. There's a couple thousand "person-years" right there, measured over time.
In fact, very few of those LRT-related jobs will be long-term ones. Rail office boss John Jensen says some will last the duration of the project; others will be short-term contracts. Even those will only make up a fraction of the overall employment gain: As the Rideau Transit Group confirms, only about four-thousand "person years" will be aportioned to tradespeople, skilled technicians and engineers. As fast as Ottawa's universities and Colleges can churn those professionals out, there remains a shortage of them here. So a good many of the local jobs -- that 80 per cent we're being promised -- will likely be those that are indirectly related to the project, the 15- or 16-thousand "person years" of work for parts suppliers and service industry workers.
As Carleton University professor Ian Lee points out, politicians love to throw around big employment numbers. But while locals will undoubtedly benefit from this massive project, Lee says the real economic benefit for the city isn't in short-term employment, but in the long term, in ways that are harder to sell from behind a podium.