Tuesday, August 16, 2011

Tickets

Safety or Revenue?

Consider the "parking to close to a fire hydrant" or corner ticket for an answer. It it was for safety, the curb would be marked, so we were not guessing where the limit is at. There you simple answer. Revenue.

Photo Radar... Speed tax.

Interesting time we live in. The governments have become the highway men, robbing from the public traffic.

Other departments are just taxing to raise revenues for there wages. They produce little benefit. We live at a time of the acceleration of the decline of the western works try at democracy. Yes, I believe we have been in decline since about 1970. There is not a single date, as different parts or functions have different peaks. Communications, with the internet is changing the world fast.   

Monday, August 15, 2011

Bloody Big Trees

Once again, I have reviewed a residence that has undergone considerable damage from bloody big trees. This time, there was a new garage / storage library, attached to the house. Once again, I assume high plastic clay. There was an small existing garage that created uneven soil moisture (assumed). Floor slab movements since the first inspection indicate shallow highly non-uniform settlement. The entire garage on shallow piles, 12 feet, is also settling, more closed to the trees. This implies that the desiccated crust is thickening. The desiccated crust is the result of the first cycle since the deposit was deposited drying out. We are starting to see a lot of similar issues in that area. There is no easy solution, other than to construct on deep foundation, or no big trees.

The entire house is surrounded with massive spruce trees and little drainage. The major offending massive deciduous trees belong to the neighbor, and the City has several close by. Now what?

Friday, July 15, 2011

Beyond the scope

A client used one of our reports for application of work beyond the scope of the report, and the County used one line in the report as defense of a project, which it could not support. The client wants us to withdraw the restriction. Now what do we do?

First the report covered a building foundation and a slope stability of a critical portion of creek slope, but the no water features applied to the entire creek length through the property. The client build a storm water management facility, a holding pond, too close to the creek. It does not comply with Alberta Environment Guidelines in a number of areas.

We have not conducted analysis of the bank at that location. The client did not conduct any testing on the roadways; hence, they are not a good client.

So here is the essentials of the letter I provided.


As requested, we has reviewed geotechnical investigation at the above noted site.  The purpose was to examine our recommendations to disallow water features within 30 metres from the top of bank along the creek, for the purpose of allowing a storm water management facility (SWMF)  (storm water pond) at the top of bank at the south end.

First, any storm water pond must comply with Alberta Environment Guidelines for SWMFs. The proposed development is short in a number of ways, assuming the plan provided is the complete plan.

The report was conducted before any SWMF was proposed on any of the plans provided, and as a result, the SWMF was not considered. It is beyond the scope of the report, and the SWMF was designed and partly constructed without any geotechnical or enginnering input from us.

The water feature setbacks, for small slopes, are normally based on a soil dependent factor multiplied by the depth of the slope, and expressed as a distance from the top of the slope. For typical clay till, 6 to 8 times the depth of slope would be typical, in this case about 3 metres, producing a typical setback of 18 to 24 metres from the bottom of the toe. However, no testholes were conducted, and we are unsure if clay, clay till, of sand lenses are present at this location. No analysis has been conducted, and the required information has not been obtained. There is also a question of the point to measure from on the SWMF.

We expect that at this location, the 30 metre water feature restriction can be reduced, but without testholes, testing, and analysis, we are unable to logically provide an exact number at this location. In addition, there are inside pond slope issues and erosion issues that are not addressed in the plans provided to us.  A specific geotechnical investigation would be required to address the SWMF and the setback, along with redesign to comply with the current Alberta Environment guidelines. 

Monday, June 27, 2011

What / Who influenced my life

Who were the big influences in my life?

As I reach retirement, in this stage of semi-retirement, I have a bit of time to reflect, and answer for myself questions like who and what have been the influences, the turning points in my life?

My philosophy of life has in the early years was running from the farm, what now would be considered as an abusive environment, not toward anything. After escaping, I worked a few years, and one cold winter, decided to get a bit of education so that I would not need to work outside at a temperature of -54 F. I selected Civil Technology because I could qualify to enter the program, and afford it. The field I selected was soils, largely due to numerous jobs in it that year, and I did not like surveying or drafting, the other choices. The job I choose upon graduation was the first one offered (desperation). I did not even get an interview with the government, and they had lots of jobs that year (My English was not good enough).

I stayed at that job due to the lack of direction in my life, and parts of the job was interesting; I got to see much of Northern Alberta, a few days here and there, a few months here, a few months there. No fixity, drifting as directed, no real long range plan, in reaction to the construction industry, the whims of developers, the requirements of government, specifications, building codes, and occasionally because someone wanted or need information. Some of them actually listened to what we found and used the data we collected. Others did not. I thought I could do as well as they did. And I was still in the cold in the winters. It had become time to settle down. I needed roots. Entered engineering, not as the first choice, but as a potential career with decent prospects. I looked at psychology, or other soft sciences, but as Dick put it, after 6 years of study, you will likely be making less than you are now.

So off to Civil Engineering I went, graduated, and returned to my former employer. After a few years, I needed a change, and tried some peripheral areas of what I had been doing, and then went back. The crash caused by Trudeau's National energy program came and jobs engineering tried up. I tried, did bits and bites of this and that, but did not work steady for ten years. I took master level courses, and then I would get a job for a while. I ended up with the course work for more than a masters, but never got the requirements in time or did the thesis.  I considered moving to where the economy was better, but my parents were old and I felt tied to Alberta, to be close enough to help them occasionally. Trapped by guilt, duty, or the like; a source of resentment, and obligation, without any acknowledgement. Not a good situation. Then in the early 90's, the surplus of engineers was gone, and the economy had returned, but I no longer had the energy, the drive necessary to work the long hours that is required for the technical introvert with poorer English and a dislike of writing.

The psychological / philosophical influences can be simply listed, Dale Carnige, Norman Vincent Peal, Gabrante, Kay McKenzie Gold,  AA/OA, Engineering Management, Buddhist readings, and the Internet blogs. These all combined to form what I am today, a twisted work in progress.  The people that influence positively and negatively are numerous and as some remain active, I will not list then. For those that know, Harold, John and 'Wilson and Smith', change my life many ways. There was the girl that knew she was going to raise kids and sheep, that cause me to redirect my life toward something, rather than away from something.

Once I started down the canyon that my career was, there was no escape, just carrying on. When I got tired, I just drifted, and dealt with what came up. I took some detours, some dead ends, and many misdirects. Some were my own decisions, and some were bad information, fraud, deceit, and lies.

Along the way I realized that most people are motivated by there own values, usually greed or the pursuit of money, fame, not the good of humanity. They would do anything for money, or avoid failure. Fraud, theft, deceit, anything.

One of my former employers sold leased vehicles to a different leasing company and leased them back. He got some cash, but was paying two leases. He also stopped remitting the premiums to an insurance plan, and for a while paid the expenses, until it was discovered. He was COD most everywhere. Interesting times. Paychecks bounding, final expense claims not paid. Such fun. See you in hell, Billy.

Sunday, June 19, 2011

Frye and Swelling - Shrinking under buildings

Frye is a legal standard of evidence, the lowest of which is the opinion of an expert. That would be superseded by test data, and ultimately by proof.

With foundation movements, it is impossible to go back in time to monitor moisture change in the soil below a basement so absolute proof does not exist for a specific basement. It has been shown to occur in research.

A expert can look at a structure, in a area known to have high swelling soils, note the trees, perhaps some wetter areas near downspouts, and if there is a correlation with distance from a major tree and the amount of shrinkage, that is the floor points to a tree, it is likely that shrinkage is to blame. It it point up at a drain spout, or a source of water, swelling is likely.

Now to remove doubt, one step at a time. First to demonstrate the soil has swelling/shrinkage potential. There is a good correlation between Atterberg limits, a index test for classification, and swelling. That only tells us that the soil is capable of swelling or shrinking. Add some moisture tests, and we can know that it is within the normal range that shrinking and swelling occurs. When we have condition that is dryer at the tree, wetter away from the tree, for similar soil and strata, the data would suggest that the tree is drawing water from the soil. But all trees draw water from the soil, and most draw more adjacent to the tree than away. This can get altered where there is a drain spout at the tree. Ideally the best demonstration we ever get after the fact, is a high plastic soil, and higher moisture contents at the high points of the structure. A range of moisture can usually be established.

There are odometer tests, where a "undisturbed" sample of soil is placed in a testing apparatus, the height measured, it is saturated, loaded, in steps over time, and allowed to swell, consolidate, rebound, and the results are analysed. But usually the soils in the field are not saturated to start with, so it tells more about the soil and its potential than what actually happened.

Now for the complication. Lacustrine deposits are varved, that is there is a variation in the clay/silt ratio with depth, often varying 40/60 to 60/40 in a few inches, or a foot vertically and be visually indistinguishable. The Atterberg limits, moisture content, hence the swelling potential, and the moisture holding capacity also vary. Comparing the moisture's without Atterberg limits on each sample is little better that an option mixed with some test data.

Now if we do four testhole, to 12 feet, with 12 samples per testhole, do moisture on all samples, limits on all samples, at about $100 each plus sampling, logging, field time, you have a nice bill, for a better suggestion of the possibility. Some of that data will be meaningless, or misleading, so what to do, we ignore some of the tests.  Suppose we do four testholes to 12 feet, a sample/foot , moisture on all, and say 4 limits on selected samples. Now we are introducing bias of the geotechnical engineer who is selecting the samples to conduct limits on, unless we say something like even testholes at foundation level, odd testholes at 1 foot below foundation level. Then it is biased by the person selecting the testhole order or locations.

The location must be selected to show the range, 2 in the dry areas, 2 in the wet areas. Ideally for a house, we would like two in the high area, two in the low area. This may mean 2 inside, and two out. To make matters worse we may may looking for 2 percent difference dryer hole to wetter hole, when over a few inches, the soil may vary 4 percent vertically in one testhole, so "proof" is not always obtained. The suggestion may be there in the data, or perhaps not. So now we can have a question as to what the data really shows.

One testhole in a area expected to be wet, at a downspout not near a tree, and one near a tree, not near a downspout, can be the best demonstration variability, with moistures every 1 foot, to 3 or 4 feet below the foundation may be advisable and a few limits just below the foundation level.

Now testholes on private property requires two liability wavers, one from the home owner and the insurance company we are working for must be willing to pick up the risk of a unknown utility strike. All known utilities can be located, both public and private, and avoided.  This assumes that locations are available and accessible.

Next is the other issue, the method. Inside is hand work. Coring through concrete floors is messy. Hand auguring below is tough work, and requires a skill that must be trained into people doing manual work, as well as myself to observe, and a junior engineer to sample and log the testholes. This all assumes that there are suitable locations to conduct testholes. Where the house is surrounded with trees, the outside testholes can be a issue also. Finding a "wet locations" that is clear of utilities is not always obvious, and close to the house. The front or rear lawn, well away from the house is often the only choice. Close to a tree, or within the same from the tree as the house is is often the best available choice for the "dry location".

Wednesday, June 15, 2011

Residential basement

Residential basements, as part 9 of the ABC allows them to be built are fragile.  They just break to easily, when anything heavy get near them. This is a problem for anyone working around these thing. They are just dangerous.
Vibration can produce lateral loads on them and fail them. They rapidly break with swelling clay or shrinking clay.

Tuesday, June 7, 2011

Vibration

Vibration Damage is a insurance issue, in that every time a home owners feels vibration from a construction project, the owner claims damage occurred. Frequently, the damage is obviously preexisting. But occasionally damage from vibration does occur. Any time a compaction roller gets closer than 25 feet to a residential concrete basement, built to just the minimum Alberta Building Code standards, the lateral forces are high enough to potentially cause damages. Drop weight concrete breakers and big back hoes which lift and drop concrete, pile driving operations, deep soil compaction, and well fracing all can cause damage.

Wet soils and vibration sensitive silts are particularly bad. Wet soils lateral pressures attenuation is low. Vibration sensitive silt can cause settlement at considerable distance.