TAMWAVE 7: Analysis for a Cohesive Soil


With the analysis of the concrete pile in cohesionless soils complete, we turn to an example in cohesive soils.

The analysis procedure is exactly the same.  We will first discuss the differences between the two, then consider an example.

Differences with Piles in Cohesive Soils

  • The unit weight is in put as a saturated unit weight, and the specific gravity of the soil particles is different (but not by much.)
  • Once the simulated CPT data was abandoned, the “traditional” Tomlinson formula for the unit toe resistance, namely $latex q_t = N_c c $, where $latex N_c = 9 $, was chosen.
  • The ultimate resistance along the shaft is done using the formula of Kolk and van der Velde (1996).  This was used as a beta method, for compatibility with the method used for cohesionless soils.  Unless the ratio of the cohesion to the effective stress is constant, the…

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TAMWAVE 6: Results of Wave Equation Analysis


With the data entered for the wave equation analysis, we can now see the results.  There’s a lot of tabular data here but you need to read the notes between it to understand what the program is putting out.  If you are not familiar at all with the wave equation for piles, you need to review this as well.

General Output for Wave Equation Analysis
Time Step, msec 0.04024
Pile Weight, lbs. 15,000
Pile Stiffness, lb/ft 600,000
Pile Impedance, lb-sec/ft 57,937.5
L/c, msec 8.04688
Pile Toe Element Number 102
Length of Pile Segments, ft. 1
Hammer Manufacturer and Size VULCAN O16
Hammer Rated Striking Energy, ft-lbs 48750
Hammer Efficiency, percent 67
Length of Hammer Cushion Stack, in. 16.5
Soil Resistance to Driving (SRD) for detailed results only, kips 572.7
Percent at Toe 35.39
Toe Quake, in. 0.220
Toe Damping, sec/ft 0.07

For those familiar with the…

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TAMWAVE 5: Wave Equation Analysis, Overview and Initial Entry


With the static analysis complete, we turn to the wave equation analysis.  TAMWAVE (as with the previous version) was based indirectly on the TTI wave equation program.  Although the numerical method was not changed, many other aspects of the program were, and so we need to consider these.

Shaft and Toe Resistance

Most wave equation programs in commercial use still use the Smith model for shaft and toe resistance during impact.  Referencing specifically their use in inverse methods, Randolph (2003) makes the following comment:

Dynamic pile tests are arguably the most cost-effective of all pile-testing methods, although they rely on relatively sophisticated numerical modelling for back-analysis. Theoretical advances in modelling the dynamic pile-soil interaction have been available since the mid-1980s, but have been slow to be implemented by commercial codes, most of which still use the empirical parameters of the Smith (1960) model. In order to allow an appropriate…

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TAMWAVE 4: Shaft Resistance Profile, ALP and CLM2


With the basic parameters established, we can turn to the static analysis of the pile, both axial and lateral.

Shaft Resistance Profile

Shaft Segment Properties
Depth at Centre of Layer, feet Soil Shear Modulus, ksf Beta Quake,inches Maximum Load Transfer, ksf Spring Constant for Wall Shear, ksf/in Smith-Type Damping Constant, sec/ft Maximum Load Transfer During Driving (SRD), ksf
0.50 48.4 0.163 0.0022 0.009 4.03 45.394 0.009
1.50 83.9 0.163 0.0038 0.027 6.99 19.911 0.027
2.50 108.3 0.163 0.0050 0.045 9.02 13.572 0.045
3.50 128.1 0.163 0.0059 0.063 10.68 10.543 0.063
4.50 145.3 0.163 0.0067 0.081 12.11 8.730 0.081
5.50 160.6 0.164 0.0074 0.098 13.38 7.509 0.098
6.50 174.6 0.164 0.0080 0.116 14.55 6.623 0.116
7.50 187.6 0.164 0.0086 0.134 15.63 5.948 0.134
8.50 199.7 0.164 0.0091 0.152 16.64 5.414 0.152
9.50 211.1 0.164 0.0097 0.170 17.59 4.980 0.170
10.50 222.0 0.164 0.0102 0.188 18.50 4.618 0.188
11.50 232.3 0.164

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TAMWAVE 3: Basic Results of Pile Capacity Analysis


With the soil properties and lateral loads finalised, we can proceed to look at the program’s static results.  These are shown below.  We will concentrate on cohesionless soils in this post; a sample case with cohesive results will come later.

Pile Data
Pile Designation 12 In. Square
Pile Material Concrete
Penetration of Pile into the Soil, ft. 100
Basic “diameter” or size of the pile, ft. 1
Cross-sectional Area of the Pile, ft2 1.000
Pile Toe Area, ft2 1.000
Perimeter of the Pile, ft. 4.000
Soil Data
Type of Soil SW
Specific Gravity of Solids 2.65
Void Ratio 0.51
Dry Unit Weight, pcf 109.5
Saturated Unit Weight, pcf 130.5
Soil Internal Friction Angle phi, degrees 32
Cohesion c, psf
SPT N60, blows/foot 20
CPT qc, psf 211,600
Distance of Water Table from Soil Surface, ft. 50
Penetration of Pile into Water Table, ft. 50

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TAMWAVE 2: Modifying the Soil Properties


With the first step out of the way, we can proceed to the second: allowing the user to modify the properties of the soil.  This option must be used with care since it is easily possible to put together a set of soil properties that is physically unrealistic if not impossible.

Also, if you have chosen a sand or clay, you have chosen the methodology you will use.  Adding cohesion to a sand or gravel, for example, will have no effect on the subsequent performance of the model.

Finally, depending upon the choice of a free or fixed head, you are given the option of entering lateral loads and/or moments for the pile head.  In this case we have opted to add a lateral load of 10 kips to the pile and no moment.  The default is zero for both load and moment; this will produce some coefficients but…

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TAMWAVE 1: Entering Basic Soil and Pile Properties


With a few preliminaries out of the way, we can proceed to discuss the new TAMWAVE routine, which can be found here.

What is TAMWAVE?

TAMWAVE stands for Texas A&M Wave Equation.  The TTI wave equation was developed at Texas A&M in the late 1960’s and early 1970’s, and was a successor to Smith’s original wave equation program.  In reality this is more than a wave equation program; it is a driven pile analyser which, in addition to the wave equation program, analyses the static performance of a driven pile for both axial and lateral loads.  It is not intended to be used on actual projects, but as an educational tool for students.  Most of the software in current use is expensive, and predecessors such as SPILE, WEAP87 or COM624 are hard to use (they’re DOS programs) or methodological obsolescence issues.  (With WEAP87, there are not as…

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Relating Hyperbolic and Elasto-Plastic Soil Stress-Strain Models

It is routine in soil mechanics to attempt to use continuum mechanics/theory of elasticity methods to analyse the stresses and strains/deflections in soil. We always do this with the caveat that soils are really not linear in their response to stress, be that stress axial, shear or a combination of the two. In the course […]

via Relating Hyperbolic and Elasto-Plastic Soil Stress-Strain Models — vulcanhammer.net

We’ve Moved At Last, But Took the Online Pile Routines Somewhere Else

After a summer of eclipses and hurricanes, we’re pleased to announce that vulcanhammer.info has finally moved to its new platform as of yesterday.  Click here and check out what we have to offer.  Most of the content has gone with the site; we’ve added many photographs and used the transition to correct many of the errors that have crept in during the ten years the site has been in existence.  (For regular visitors, thanks for your support over the years.)

Moving to WordPress gives us three key advances:

  1. Better integration with social media.
  2. Secure browsing.
  3. The ability for you to leave comments and questions for us.

One set of routines that didn’t come with it are our TAMWAVE wave equation analyser, along with our other active pages (such as the fixed end sheeting analyser and Mohr’s Circle triaxial calculator.)  WordPress doesn’t allow active content like that on their site; however, it’s still available at our auxiliary page.  You can click here to visit these.  Lord willing we’ll be adding and updating these, which have been very useful teaching tools.

Thanks again for your support.

Vulcan’s Centennial Celebration

1952-2aThe centennial celebration was one of the finest gala events — and certainly the best documented — that Vulcan ever put on. Following are some facts about the celebration:

  • The banquet took place on 31 January 1952. It was scheduled to coincide with the end of the AED (Associated Equipment Distributors) meeting in Chicago.
  • The celebration was held at the Sheraton Hotel, Grand Ballroom, Chicago, Illinois. It began at 6:00 pm, with cocktails, then the dinner, and after that the speeches.
  • Music for the event was provided by Shay Torrent, a well known organist for the Hammond Organ Company. Shay was a family friend of the Warringtons for many years. It was necessary to rent an organ with Leslie speaker for the occasion.
  • Each of the guests was furnished with complementary Old Gold cigarettes for the banquet. Smoking proved the undoing of the Warringtons, though: Chet Warrington died of emphysema nine years after the celebration, son Henry’s early retirement was forced in part by the same disease, as was his death at 69, and grandson Pem’s death at age 41 was also hastened by smoking.
  • Each of the guests was also given a leather portfolio as a momento of the occasion.
  • Just before the celebration, on 17 January 1952 there was a fire at the Vulcan plant.
  • The correspondence surrounding this event is a fascinating look at a world now gone. Here are some quotes from some of the guests, suppliers, Vulcan people, and others who participated in the event:
    • “We leave Washington on the Capital Limited at 5 o’clock Wednesday afternoon…and on our arrival in Chicago the next morning, we will take a taxi…Bob is talking about flying back, but the air service is too uncertain at this time of year…I think I’ll stick to the old B&O.”
    • “…Mr. Fleming would be very appreciative if you would reserve a room and bath for him at the Sheraton as he prefers to have a room to himself rather than share it.”
    • “I was your shipping clerk at Milwaukee and Clinton fifty years ago [1902] when Mr. [Henry] Warrington Sr. was alive…Mr. Wm. Warrington had charge of the machine shop. I’ll say men really worked in those days his work was his soul…I wish you another hundred years but won’t be able to be here as I am eighty years now.” (G.C. Lind, Oak Park, IL)
    • “Illness as a result of an epidemic in this and many other cities in Ohio have prevented me from acknowledging before this receipt of a fine leather document case…”

Chet Warrington’s Keynote Speech
31 January 1952

Ladies and Gentlemen:

It is a unique occasion which brings us together this evening. In the inception, I desire on behalf of all of us of the Vulcan Iron Works, to thank all of you for responding so readily to our humble efforts to make this occasion one which all will remember with pleasure. I am indeed happy that I am in a position to call together such a body of outstanding men. The occasion is somewhat of a story of one man from England, who came to this country, then to Chicago in 1847, worked hard and built a successful industry. We have heard such stories many times before. The one about the Detroit mechanic who put a nation on wheels. One about the brooding genius from Milan, Ohio who heated carbon filaments with electricity to produce the most brilliant illumination man had known. One about two bicycle mechanics of Dayton who were obsessed with the idea that man could fly.

We read them in school books, reread them in newspapers and magazines. We got a bit bored with success. Where, doubters asked, had it gotten us. We forgot too readily that these stories were the very fabric of America, a living history of events which built a great nation. We forget that they made us materially wealthy — that they furnished the means with which to nourish a precious heritage of liberty. They and countless others, before and after them, inspired and inspiring the precepts and philosophy of a great and growing era of free enterprise.

Construction equipment is a desperately ordinary factor to us today. Yet its discovery is probably one of the greatest in history. When some forgotten ancient found a sudden need for constructing bridges, in order that the warring legions might readily cross, his conception of pile driving gave man an added means to then expand his activities to the through parts unknown. The Greeks knew of this as did the Romans — the product of this effort was expensive even then and reserved to Conquerors, Kings and Potentates. Not until modern industry came along, demonstrating the virtues of power products, among them the Warrington-Vulcan pile hammer did the construction equipment industry fully realize the potentials ahead. With full realization of these factors and the few years of previous experience, Henry Warrington decided to definitely cast his lot and future in and with Chicago, deciding this could be most effectively done through the organization of a family company. This was immediately done and continued as an individual enterprise until his three sons had reached an age to materially assist, at which time he transferred the Vulcan Iron Works to a corporation. His conception of such an organization included specific essential attributes of the then young corporation — Character — Personality — Philosophy. He believed traits of character to be the property of the company — not its current management. Management is a transitory body at best, occupying but a short decade or two, in the long life of any corporation. A single management’s influence there is at best intermittent. Personality and philosophy of the Vulcan Iron Works itself therefore have been developed on this premise through three generations — and now are being carried forward to and by the fourth generation. If you will momentarily accept this precept, I think I can best tell you about the character, personality and philosophy of the Founder — Henry Warrington.

Environment and heredity it is said work strong and lasting effect on all lives. Let me go back for but a moment to the time in which the Vulcan Iron Works was born.

The needs and wants of the then restless Chicagoicans, in the small trading post on the shores of Lake Michigan, created a demand for commerce and trade. As a result this infant city became a Mecca for thoughtful men of foresight. In the beginning profits of the Vulcan Iron Works came from general and marine requirements. There was a new era dawning for the West and all ambitious men who had staked their future in the stability and progress of Chicago appeared to be on the threshold of success — save for one thing — Fire (1871). The results and details of this catastrophe are a matter of record and history in the annals of Chicago. However, this discouraging, yet challenging environment, only increase the original conceptions of Henry Warrington whose single purpose was that of contributing to the then economic stability and progress of the community, and his own family as well. Adversity during the early years of one’s life builds qualities of strength and perseverance. Bold temperament and spirit, dominant influence over the organization inculcated in his three sons, William, George and James, who were to follow him, became influences that left an indelible mark on, and in the making of the Character and Philosophy of the Vulcan Iron Works. I would be remiss in not mentioning them here.

And so we arrive at the commemoration of a century of manufacturing here in Chicago producing pile driving equipment and accessories. We are humble in our position today as being the largest exclusive manufacturer of such in the world today. The small factory on Milwaukee Avenue with its twenty employees survived and grew because it produced a better product. Every business lasts and grows by serving. Through these one hundred years four generations of the Warrington family have and are serving. We have served our customers as specialists in the development and economical production of high efficiency construction equipment. As such specialists we have contributed our share through the years to the evolution of the modern pile driver and extractor.

One hundred years is a long time, both in the span of human lives and of business. Every, or any business, which reaches that age owes its accomplishments not merely to sound management, but to people, forces and circumstances that have made such vitality and growth possible.

We have in mind tonight —

  • OUR EMPLOYEES — whose team work and harmonious relationship with management are outstanding.
  • OUR CUSTOMERS — in the vast construction industry including over one hundred distributors of construction equipment in the United States as well as many overseas representatives.
  • OUR SUPPLIERS — from whom we buy materials, machine tools, and the thousand of other things we need to operate our plant and produce for our customers.
  • THE COMMUNITY — in which our plant is located, that provides the workers we must have in times of peace and war.
  • THE BLESSINGS — of the country in which we live. Only in America with its free economy, free society, and unmatched standards of living can there be industries like ours.

To these we make humble acknowledgment on our one hundred anniversary, and because of them, we look with confidence into the next century of our history.