In an evolutionary scene, we engineers hunt with a pencil. We consulting engineers are the storehouse of designs, concepts, ideas, computing models, formulas, data, and some theories, and many approximations of the physical world as it was, which we pull off the shelf, add a bit of site specific data, adjust the model, turn the crank three times to the left, flick the accumulator switch, once to the right, put in a bit more data, or take some out, turn the crank a few more times, and come up with an answer (If you are old enough to remember the Curta Calculator). The final step is to communicate the answer to the client. Before this can happen, we must know what we are hunting for, and where to find it.
We had better know the answer in a general way at least, or what data we will need and where to get it before we take on the project. If it is reclamation, we had better know the cause of the original failure, and how to avoid it, or if we are dealing with time and wear, what the clients current and expectations are.
Traffic loads are increasing, not only in volume, but the governments have and are increasing legal loads. This has a tremendous impact on the cost of roads, at public expense. These legal loads come onto private property, and pavements must be thicker to support them. The equipment that loads and unloads them is large, more heavy pavements. The building that house them are large, heavier loads. Buildings in general are large, heavier, and the clients are only looking at dollars in most decisions now.
It has become a much more difficult struggle to operate a small firm. The specialization has made it difficult to find suitable replacement personnel. Burnout of senior people, myself in particular, is the issue.
Thursday, April 26, 2012
Sunday, April 8, 2012
Asphalt Pavements
How do we repair asphalt pavements that are in need of overlay and there is no money?
Well that is a hard question. Water is the main issue. Overlay patch anywhere that water stands after a shower. Truck dumped and grader leveled asphalt is the best solution, equivalent to a leveling course. Seal to prevent water ingress. Water softens the support and hastens failure.
Expect heavier overlays.
Cracking will continue at a faster rate. New cracks and old cracks growing in length and width will create additional issues, so annual sealing via spray chip seal is the best patching method, where water is draining.
It becomes repeat the truck dump patching and spray seal annually until the road/pavement has been evaluated, and a structural over lay has been applied.
Most of the roads that I have designed the pavement thickness on were constructed with less asphalt and gravel than I recommended. This reduces a 20 year design, that should be overlayed at 15 years, to something less. When the next government administration asks why it is failing at 10 years, all involved have mover on. Say la vie.
Well that is a hard question. Water is the main issue. Overlay patch anywhere that water stands after a shower. Truck dumped and grader leveled asphalt is the best solution, equivalent to a leveling course. Seal to prevent water ingress. Water softens the support and hastens failure.
Expect heavier overlays.
Cracking will continue at a faster rate. New cracks and old cracks growing in length and width will create additional issues, so annual sealing via spray chip seal is the best patching method, where water is draining.
It becomes repeat the truck dump patching and spray seal annually until the road/pavement has been evaluated, and a structural over lay has been applied.
Most of the roads that I have designed the pavement thickness on were constructed with less asphalt and gravel than I recommended. This reduces a 20 year design, that should be overlayed at 15 years, to something less. When the next government administration asks why it is failing at 10 years, all involved have mover on. Say la vie.
Sunday, February 12, 2012
High Bearing Values
High Bearing Values and ABC Geotechnical Schedules
Here is one response that can be placed in the cover letter that sets out the limits where the bearing values are a bit on the high side.
The bearing value provided in the geotechnical investigation report (GI) is higher than we would typically provide within that formation and area. There is no test data contained within the GI report support such a value based on conventional data conversion for typical construction. The value is acceptable for flexible construction.
We are therefore proceeding on the basis that we are accepting the bearing value at face value; however, differential movements may be excessive for some styles of construction and suitable for others. No information has been provided on the structure or performance expectations.
Here is one response that can be placed in the cover letter that sets out the limits where the bearing values are a bit on the high side.
The bearing value provided in the geotechnical investigation report (GI) is higher than we would typically provide within that formation and area. There is no test data contained within the GI report support such a value based on conventional data conversion for typical construction. The value is acceptable for flexible construction.
We are therefore proceeding on the basis that we are accepting the bearing value at face value; however, differential movements may be excessive for some styles of construction and suitable for others. No information has been provided on the structure or performance expectations.
Thursday, February 9, 2012
Insurance and Foundation Movement
In general, home insurance does not cover foundation movements. Some insurance may cover damage due to foundation movement. You fix your foundation (the big cost) they may cover the damage to interior (drywall patches, painting).
We are located in what was a glacial lake, which became a mud flat after the lake drained. Much of this area has high plastic soils. We have had a number of dryer years, the big tree now have roots through the desiccated crust, into the moister soils, drawing water from them, and in effect thickening the desiccated crust, with accompanied movements. Recent rains have created some surface swelling, with associated lateral pressures.
We can do an inspection of the damages and provide an opinion as to the probable cause(s). With residential construction, there are often additional problems to the foundation movements. Poor design, that the expected performance is not satisfactory, wrong construction, poor construction, incomplete construction, poor repairs, and may other problems exist. Inspections are conducted at a hourly rate, including travel time, inspection time, any research time digging through archives, and report writing time.
We can also conduct a geotechnical investigation to determine soil index parameters, or actual values, and an indication of the swelling potential a number of ways. The next step is typically a minimum four deep macro-core test holes, with moisture contents, Atterberg limits, remaining linear shrinkage to oven dry estimates, hand auger holes inside the structure, site surveying, house level survey, drafting of the collected data, and a engineering report. The current cost are typically $7000 to $15000.
We are located in what was a glacial lake, which became a mud flat after the lake drained. Much of this area has high plastic soils. We have had a number of dryer years, the big tree now have roots through the desiccated crust, into the moister soils, drawing water from them, and in effect thickening the desiccated crust, with accompanied movements. Recent rains have created some surface swelling, with associated lateral pressures.
We can do an inspection of the damages and provide an opinion as to the probable cause(s). With residential construction, there are often additional problems to the foundation movements. Poor design, that the expected performance is not satisfactory, wrong construction, poor construction, incomplete construction, poor repairs, and may other problems exist. Inspections are conducted at a hourly rate, including travel time, inspection time, any research time digging through archives, and report writing time.
We can also conduct a geotechnical investigation to determine soil index parameters, or actual values, and an indication of the swelling potential a number of ways. The next step is typically a minimum four deep macro-core test holes, with moisture contents, Atterberg limits, remaining linear shrinkage to oven dry estimates, hand auger holes inside the structure, site surveying, house level survey, drafting of the collected data, and a engineering report. The current cost are typically $7000 to $15000.
Tuesday, January 31, 2012
Out to Lunch
How should one handle the situation when the "authority having jurisdiction" is out to lunch on a particular topic?
We see this in the building code, in nutritional recommendations, in medical recommendations, and in the past religion, when it had real influence. One way is to write a book, do a blog, or a web site and publish it. The information is then out there, in the public domain, where people are free to chose to understand or not.
This is considered dissonance of some kind, in the past it might have been treason or heresy. Now it is rebellion, but what is the best solution?
We see this in the building code, in nutritional recommendations, in medical recommendations, and in the past religion, when it had real influence. One way is to write a book, do a blog, or a web site and publish it. The information is then out there, in the public domain, where people are free to chose to understand or not.
This is considered dissonance of some kind, in the past it might have been treason or heresy. Now it is rebellion, but what is the best solution?
Saturday, December 24, 2011
Some will understand
Buddha decided to teach what he had learned with the idea, "Some will understand".
Some of his "learning" was likely hunger induced hallucinations. Other were random good insights and summaries. Some are built on the tribal culture and religion of the time and location.
These are only my opinions on the various readings I have done.
Compassion and the elimination of suffering is the main concept. Buddha recognized that suffering is an inside job, a self induced feeling, and that that feeling can be nominalized by a series of concepts, beliefs, values, ways of thinking and actions. Various translations and repeated expressions create a range of ideas of what each component really says. The four Noble truths go something like this:
1. Life contains suffering, pain, impermanence, toxicity, loss, stress, vaguity, distress, depression, pain causing things. The pain is an internal mental object, not a physical reality except if it is our body, but even then, the pain is a mental object. The unsatisfactory quality of life which is targeted mental object, the sorrow and trouble, the never completely fulfilling. We always want more happiness, less pain. But this ‘wanting more’,the longing, is itself the problem, the craving, the desire for more. Buddhism does help the physical, but first, it removes the internal mental object in ourselves.
2. The second part is it is our cravings, our attachments, our selfish grasping after pleasure and avoiding pain that causes the problem. Our delusions of how life should be, our attachment to people, property, prestige, and money, our aversion to loss of people, property, prestige, and money, or simple attachment, delusions, aversions are the cause. Again, these are internal, mental objects. It is not necessarily the real loss, just the potential of loss. Many religions find it easier to have real poverty than deal with the mental potential of loss, or the issues that desire for these things can bring.
3. the third is there is a solution to all this,
4. The solution is following the eight fold path to a peaceful serene state of mind.
Some of his "learning" was likely hunger induced hallucinations. Other were random good insights and summaries. Some are built on the tribal culture and religion of the time and location.
These are only my opinions on the various readings I have done.
Compassion and the elimination of suffering is the main concept. Buddha recognized that suffering is an inside job, a self induced feeling, and that that feeling can be nominalized by a series of concepts, beliefs, values, ways of thinking and actions. Various translations and repeated expressions create a range of ideas of what each component really says. The four Noble truths go something like this:
1. Life contains suffering, pain, impermanence, toxicity, loss, stress, vaguity, distress, depression, pain causing things. The pain is an internal mental object, not a physical reality except if it is our body, but even then, the pain is a mental object. The unsatisfactory quality of life which is targeted mental object, the sorrow and trouble, the never completely fulfilling. We always want more happiness, less pain. But this ‘wanting more’,the longing, is itself the problem, the craving, the desire for more. Buddhism does help the physical, but first, it removes the internal mental object in ourselves.
2. The second part is it is our cravings, our attachments, our selfish grasping after pleasure and avoiding pain that causes the problem. Our delusions of how life should be, our attachment to people, property, prestige, and money, our aversion to loss of people, property, prestige, and money, or simple attachment, delusions, aversions are the cause. Again, these are internal, mental objects. It is not necessarily the real loss, just the potential of loss. Many religions find it easier to have real poverty than deal with the mental potential of loss, or the issues that desire for these things can bring.
3. the third is there is a solution to all this,
4. The solution is following the eight fold path to a peaceful serene state of mind.
Tuesday, December 6, 2011
Surrogate Measurement vs Real Measurement
Surrogate Measurement vs Real Measurement is an issue in many things beside soils. The medical industry uses surrogate measurement for a lot of things.
Surrogate measurement is the concept of measuring something that generally relates to a desired property, that is difficult to measure. The swelling potential of soil is time consuming test, but the moisture content, liquid and plastic limits can be determined in a day. There is a direct relationship between the liquidity index and the swelling potential, so we determine the liquidity index and imply a swelling potential.
As long as that relationship between the liquidity index and swelling potential holds, we are in good shape. But add any one of a long and growing list, and we are out to lunch by a long shot. Gasoline, any petroleum, soap, or even organic staining, and the correlation is out. Now we must do the full consolation with swelling, to find one point. We may need a number of points, depending on the situation. Each point is 12 days at least, if a (the) consolidation frame is available.
We would need to do the test to even find out that the relationship does not hold for this sample.
Those time do not include any sampling time involved, nor sample quality issues.
Now what about the medical field. wtf. They use more surrogates than we do in engineering. If you are producing enough iodine in you urine, you are not short. 20 years of misery, and Oh, you are not absorbing enough iodine. wtf.
Oh well shit happens. The medical industry knows what it knows, which is considerable less than they indicate that they know. If they do not deliver results, they do not have a solution. Trying something may be the only true test of whether it will work or not.
Surrogate measurement is the concept of measuring something that generally relates to a desired property, that is difficult to measure. The swelling potential of soil is time consuming test, but the moisture content, liquid and plastic limits can be determined in a day. There is a direct relationship between the liquidity index and the swelling potential, so we determine the liquidity index and imply a swelling potential.
As long as that relationship between the liquidity index and swelling potential holds, we are in good shape. But add any one of a long and growing list, and we are out to lunch by a long shot. Gasoline, any petroleum, soap, or even organic staining, and the correlation is out. Now we must do the full consolation with swelling, to find one point. We may need a number of points, depending on the situation. Each point is 12 days at least, if a (the) consolidation frame is available.
We would need to do the test to even find out that the relationship does not hold for this sample.
Those time do not include any sampling time involved, nor sample quality issues.
Now what about the medical field. wtf. They use more surrogates than we do in engineering. If you are producing enough iodine in you urine, you are not short. 20 years of misery, and Oh, you are not absorbing enough iodine. wtf.
Oh well shit happens. The medical industry knows what it knows, which is considerable less than they indicate that they know. If they do not deliver results, they do not have a solution. Trying something may be the only true test of whether it will work or not.
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