Author: Arthur S. Koenig, P.E., 1991
Sponsor: Expansive Clay Research Institute - ECRI Publication #001

ABSTRACT
Many forensic engineers perform foundation distress studies on residential structures. One of the first tasks of such investigations is to make judgements concerning how much movement the foundation has experienced. It is commonly accepted that residential foundations can be placed out of level, and that in some cases, this may account for some, if not all, of the elevation differences measured during the examinations. For example, engineer's have been overheard saying something along the lines of, "I looked at a foundation that was 2 inches out of level, but it was probably constructed that way."

This paper explores and answers the question raised by such remarks; namely the question of how much "out of level" are newly constructed foundations. The paper presents the statistical results of a study to measure the relative elevations of points at the middle and perimeter of residential foundations within several weeks of initial placement.

The study indicates that residential foundations are actually placed within a much narrower band of error than commonly thought. The paper provides data allowing performance judgements to be supported by facts rather than speculation.

Keywords: foundations, structural engineering, geotechnical engineering, forensic, elevations, relative elevations, floor flatness, foundation distress, statistics, water level, engineering, homebuilder, residence

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Author: Arthur S. Koenig, P.E., 1991
Sponsor: Expansive Clay Research Institute - ECRI Publication #002

ABSTRACT
This paper presents an analysis of floor slab deflection data on 148 distressed residential dwelling foundations prior to their repair by underpinning. The intent of the study was to determine just how "bad" foundation distress had to get before homeowners' felt that problems needed correction, i.e., that there was a structural "failure" needing correction. The indicator of distress studied was that of maximum deflection from high to low point on the distressed slab.

Keywords: foundations, structural engineering, geotechnical engineering, forensic, elevations, relative elevations, floor flatness, foundation distress, statistics, water level, engineering, homebuilder, residence, underpinning, economics

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ABSTRACT
Foundations constructed over expansive clays can experience substantial heaving movement related to moisture content changes in the soils brought about by leaking water or sewer lines.

Due to the introduction of new technology that is able to conveniently obtain high quality continuous Shelby tube samples from underneath foundations, information is being collected that forms a data base for evaluation of the moisture and physical property characteristics of such wetted soils.

This paper presents the general difference characteristics that have manifested themselves upon analysis of soils from underneath foundations that have water leaks, or "free water" zones and those that don't. The data gathered thus far indicates that there is a definite and measurable moisture wave front associated with "leak wetted" soils. It also indicates that a key indicator of free-water wetted soil is the value of soil-moisture and its relation to the soil plastic limit. Soils under slabs with leaks, or observed ground water intrusion, have moisture contents that are at or above the Plastic Limit. The water leak cases studied presented moistures approximately 2 to 3 points above the PL. Ground water intrusion cases had moistures in the ground water zone of 5 to 8 points above the PL. Areas of soils affected by tree roots, as known from roots in the samples, had moistures that were approximately 2-3 points below the PL in the high moisture zones and 5-9 points below the PL in the low moisture zones. Investigation of structures not having water leaks or free-water indicates that the moisture content under the central portions of a foundation should normally be expected to have a high of "at or slightly below" the PL.

Comparison of the two soils moisture scenarios of leakage vs. no leakage indicates that the Moisture Index, defined as the ratio of MC/PL, is a good criteria for evaluation of abnormal wetness. Water leak or otherwise free water wetted soils appear to have MI's of above 1. Normal soils appear to have MI's generally less than 1.

Keywords: foundations, structural engineering, geotechnical engineering, forensic, elevations, relative elevations, floor flatness, foundation distress, statistics, water level, engineering, homebuilder, residence, moisture index, plumbing leakage, soil samples, shelby tube, GeoSampler

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Author: Arthur S. Koenig, P.E., 1991

ABSTRACT
Sampling equipment has recently been developed that makes possible the gathering of good quality, continuous Shelby tube samples and performing of penetration testing from within confined or environmentally sensitive spaces such as commonly occur in buildings.

The procedure is relatively easy and results in a much more meaningful and useful data than that derived from borings from outside, or that derived from talking auger or impact samples from within. This paper discusses the general features of the newly developed equipment and presents some typical scenarios, derived from actual case studies, outlining its use and benefits.

Keywords: foundations, structural engineering, geotechnical engineering, forensic, elevations, relative elevations, floor flatness, foundation distress, statistics, water level, engineering, homebuilder, residence, GeoSampler, soil sampling, soil samples, shelby tube, MDI Labs, xGEL Data Systems, LLC, ECRI

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Author: Arthur S Koenig, PE
Sponsor: Expansive Clay Research Institute (ECRI)

ABSTRACT
This paper discusses the "above the horizon" and the "behind the scenes", structure and operation of the Texas Insurance Claims Market in the years 1994-2003, and gives yearly hole counts, $ revenue, and $ expense numbers for one of the leading providers of drilling and testing and reporting for this foundation claims market.

The paper also discusses the overall financial impact and discloses the yearly $ revenues that were paid to the various contract laboratories in the San Antonio, Houston, and Dallas market, and shows the substantial financial impacts of this work. It proposes a revision to the existing models of engineering business operations and concludes that ecosystem partnering is a tool that yields great benefit to all parties.

Keywords: foundations, structural engineering, geotechnical engineering, forensic, elevations, relative elevations, floor flatness, foundation distress, statistics, water level, engineering, homebuilder, residence

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Author: Arthur S Koenig, PE
MDI Labs, Inc.
3130 Mindoro
San Antonio, TX 78217

Sponsor: ECRI - Expansive Clay Research Organization
ECRI Publication # 006
©4/14/2009

ABSTRACT
Cylinder-shaped plugs of expansive soil were tested to determine the weight, diameter, and length changes that occurred as drying of the samples occurred. These plugs, referred to as miniplugs, were air-dried at room temperature until the weight change of the plugs reached an apparent asymptote. As drying occurred, the samples underwent weight, diameter, and length changes. Apparent from the data was that not only were the miniplugs losing volume, but also that air was intruding into the samples even at moisture levels above the shrinkage limit. Five new soils engineering terms are presented, Moisture Elasticity, Moisture Inelasticity, Ideal Moisture Elasticity, Non-Ideal Moisture Elasticity, and Air Intrusion Ratio. Also presented is data concerning the weight and volume changes that occurred upon re-humidification of the samples.

Keywords: expansive clay, geotechnical engineering, shrinkage limit, ASTM, moisture elasticity, moisture inelasticity, ideal moisture elasticity, non-ideal moisture elasticity, air intrusion ratio, miniplug

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Author: Arthur S Koenig, PE
MDI Labs, Inc.
3130 Mindoro
San Antonio, TX 78217

Sponsor: ECRI - Expansive Clay Research Organization
ECRI Publication # 006
©4/05/2009

ABSTRACT
This paper traces the development of the xGEL LabMate Software platform and shows its evolution from the production process optimization strategies used by MDI Labs, Inc, and GeoLog, Inc during the 1991-2003 Texas insurance claims market dealing with structural damage due to expansive soils. The paper calls on engineering management to take a systems view of their business and points out that production process optimization, notably in field and lab operations, can dramatically change the firm's profit position. The paper also infers that the operation of the engineering firm can be made smoother by understanding on the part of the engineering staff that there is a host of production that occurs prior to their own production activities.

Keywords: production process optimization, automatic data capture, software design, geotechnical engineering, software architecture, production systems engineering, engineering business practice, new technology, process improvement, business management, psychology, project delivery systems, gINT, lab expense, lab testing, profitability, xGEL, xGEL LabMate

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Author: Arthur S Koenig, PE
MDI Labs, Inc.
3130 Mindoro
San Antonio, TX 78217

Sponsor: ECRI - Expansive Clay Research Organization
ECRI Publication # 007
©9/15/2009

ABSTRACT
This is a webinar presentation concerning the work processes that occur in the traditional geotechnical testing lab, the things that result in wasted time for the lab personnel. It is a supplement/companion to the paper Production Process Optimization - A New Way to Think About Business and is suitable for both engineering management & laboratory staff and meets the requirement for continuing education in some locales. If you view the presentation and want a confirmation, give us as call and we can see how to arrange sending you a confirmation.

Keywords: -

Production Process Optimization in the Geotechnical Lab (Webinar) (39 min)

Author: Arthur S Koenig, PE
MDI Labs, Inc.
3130 Mindoro
San Antonio, TX 78217

Sponsor: ECRI - Expansive Clay Research Organization
ECRI Publication # 008

ABSTRACT
A study was performed to determine the impact of "canning" on the calculated and reported index properties of a soil. Canning is the procedure where, instead of placement of a test specimen in a tare can and then immediately weighing it and recording the weight on the testing form, the specimen is placed in the tare can, covered with the can's lid, and then set aside to be weighed in later as part of a batch process that comprises weighing in of all the other samples that have been canned.

The results show that there is no difference of engineering significance in the calculated or the reported index properties for canned samples, even for times as long as 6 hours of delay between canning and weigh-in of the samples. This result is important because canning and batch processing of samples is much more efficient than the current weighing methods used in the geotechnical laboratory. A recommendation is made that the ASTM procedures for Moisture Content, and Atterberg Limits, be modified to include canning and delayed weigh-in as alternate methods included in the Mc, LL, & PL test procedures.

Keywords: canning, ASTM, Plastic Limit, Liquid Limit, Atterberg limit testing, production process optimization, automatic data capture, geotechnical, production systems engineering, engineering business practice, new technology, process improvement, business management, psychology, project delivery systems, lab expense, lab testing, profitability

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Author: Arthur S Koenig, PE
MDI Labs, Inc.
3130 Mindoro
San Antonio, TX 78217

Sponsor: ECRI - Expansive Clay Research Organization
ECRI Publication # 009
©10/15/2009

ABSTRACT
A study was performed to determine the impact of differing oven drying times on LL and PL samples. Many labs leave their samples in the oven overnight and do weigh-backs in the mornings. When asked about this, lab personnel indicate that this is because the samples " .... need time to be dried sufficiently."

In this study 2 PL specimens and 4 LL specimens were prepared and weighed prior to being put into the drying oven. They were then weighed hourly over the next 5 to 8 hrs respectively. The results show that approximately 99% of the PL weight loss occurs in the first hour of drying, with the specimen being sufficiently dry such that use of the 1 hour weight make no difference of engineering significance in the PL or the AL computations or reported result. Similar results were found for the LL samples with the drying time to no difference of engineering significance being 4 hrs.

Keywords: Soil testing, ASTM, Plastic Limit, Liquid Limit, Atterberg limit testing, production process optimization, geotechnical, production systems engineering, engineering business practice, process improvement, business management, project delivery systems, lab expense, lab testing, profitability

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Author: Arthur S Koenig, PE
MDI Labs, Inc.
3130 Mindoro
San Antonio, TX 78217

Sponsor: ECRI - Expansive Clay Research Organization
ECRI Publication # 010
©12/04/2009

ABSTRACT
ECRI Publication #008, Time Delay Effect on Atterberg Limit Values Due to "Canning" 10/01/2009 presented the results of a study undertaken to determine the impact of "canning" on the calculated and reported index properties of a soil. Canning is the procedure where, instead of placement of a test specimen in a tare can and then immediately weighing it and recording the weight on the testing form, the specimen is placed in the tare can, covered with the can's lid, and then set aside to be weighed in later as part of a batch process that comprises weighing in of all the other samples that have been canned.

Although it was concluded that canning with delayed weigh-in has little effect of engineering significance, due to the small size of the initial sample set, a recommendation was made that additional samples be tested to expand the data set. This Supplement presents the data and results of that additional work.

The results of this supplemental work also show that there is no difference of engineering significance in the calculated or the reported index properties for canned samples, even for times as long as several days of delay between canning and weigh-in of the samples. This result is important because canning and batch processing of samples is much more efficient than the current weighing methods used in the geotechnical laboratory.

Repeated is the recommendation that the procedures for Moisture Content (ASTM Test Method D 2216) , and Atterberg Limits (ASTM Test Method D 4318) , be modified to include canning and delayed weigh-in as alternate methods included in the Mc, LL, & PL test procedures.

In an interesting twist (common in research projects) the study data indicates that there may be an age effect associated with the LL test, for the data showed that soil specimens that had aged several weeks prior to the ECRI study testing had a slightly higher LL than specimens that had not similarly aged.

Keywords: ECRI, canning, ASTM, Plastic Limit, Liquid Limit, Atterberg limit testing, production process optimization, geotechnical, production systems engineering, process improvement, business management, lab testing, aging

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Author: Kenneth E. Tand, PE
Sponsor: Kenneth E. Tand & Associates, Houston Texas

ABSTRACT (by ECRI Staff)
The paper is a technical presentation given to a group of builders, developers, engineers and others in 2001. The effects of trees are inferred from several distress investigations done by the author. Several items of research interest are that the author concludes that tree roots extend deeper that what many believe, and presents his observation of fine roots found in a soil sample taken from 19 feet below grade. A novel approach to investigative understanding and technique is presented where amount of movement of the base of drilled shafts (and amount of movement of soils below those shaft�s bases) can be inferred based on differences in relative deflection between the apparently relatively stable and distress-free areas of the slab, the perimeter areas of the slab where distress is seen, and the size of the void between the slab under side and the underlying fill. The author indicates, through case study and engineering inference, that drilled piers likely need to be founded deeper than the 8-10 feet that Houston Texas designers typically consider as deep enough for light commercial construction so as to reasonably reduce movement potential.

Keywords: foundations, structural engineering, geotechnical engineering, forensic, elevations, relative elevations, floor flatness, foundation distress, statistics, water level, engineering, homebuilder, trees, tree roots, soil samples, shelby tube, drilled piers

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