Posted in Pile Driving Equipment

Pile Buck Ads 5: Vulcan 530 in Offshore Leaders

For the last of the “Pile Buck Ads,” a photo of the Vulcan 530 hammer is featured in offshore stub-type leaders.  The 530, introduced in 1978 for driving pipe piles offshore in the Gulf of Mexico, was and is used in a wide variety of pile driving projects.  In this case it’s shown to be driving concrete cylinder piles, which have become common on larger bridge projects in the last quarter century.

Posted in Academic Issues

My Rimsky-Korsakov Moment in Academia

In 1871, Nikolai Rimsky-Korsakov became a Professor of Practical Composition and Instrumentation at the St. Petersburg Conservatory.  In retrospect, given the music he composed, this is not extraordinary.  At the time, however, it was amazing.  He was still in active service in the Russian Navy.  More importantly, although he had had private music lessons and was very active with the “Five” (the group of Russian composers which gave Russian music its distinctive character,) he had never had any conservatory training!  He worked hard to make up for this, and in doing so departed from the rest of the “Five” in making conservatory training part of being a Russian composer.

Russia is a very specific country; many strange things happen there and wherever Russians go.   But maybe not as strange as we think: although I would never put myself in the rank of Rimsky-Korsakov in my own field, starting today I am a Lecturer in Mechanical Engineering at the University of Tennessee at Chattanooga.  For those of you who have followed this site for a long time, this will seem quite odd, especially considering that one of the centrepieces of this site is the geotechnical courses that I have taught for nearly twenty years.  My friend Jean-Louis Briaud, now President of the American Society of Civil Engineers, tried to encourage me with the fact that George Goble, who developed many of the tools we use in pile dynamics, started out as a mechanical engineer.  But in reality some explanation is in order.

My entry into this field was through the equipment route, specifically the Vulcan Iron Works.  That occasioned my first degree to be in Mechanical Engineering from Texas A&M University.  Impact (and later vibratory) pile driving equipment is an unusual type of equipment to design and build.  Basically it involves having a ram accelerate downwards due to gravity (with or without downward assist,) do this 30-120 times a minute, and stopped each time by deceleration which can be in the range of 150 g’s.  This eliminates many common solution techniques used for mechanical design problems.  Injected into an environment where service is frequently delayed and breakdown ruinous,  it makes for many exciting moments in business.

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The equipment, however, interacts with the pile which it is driving and the soil into which the pile is driven.  Understanding this is really important in the proper design of the equipment.  That realization came slowly but surely.  By the time my family’s time at Vulcan was coming to an end, I was in graduate school, which ultimately resulted in a MS Degree in Civil Engineering.  Before and during that time I presented several conference papers.  But by the time I received my degree, my future in the deep foundations industry was uncertain.

Although I had other activities in the following years, that uncertainty was ended by three events. The first was starting this website; to make an educational resource like this you have to have some understanding of what you’re disseminating. The second was my involvement with Pile Buck and the compilation of two books: Sheet Pile Design by Pile Buck and Pile Driving by Pile Buck.  The third was my teaching at the University of Tennessee at Chattanooga.  When my MS thesis committee chairman retired, I taught Soil Mechanics and Foundations for one academic year (2001-2) thanks to another committee member, Dr. Edwin P. Foster, the Civil Engineering department head, who evidently thought enough of my abilities to bring me on.

The University had other ideas; due to some complex budgetary issues, they could not see their way clear to have me teach these courses as an adjunct for most of the last decade.  It was not until 2009 that Ed Foster’s retirement and the concurrence of the current department head, Joseph Owino, meant that I was able to teach geotechnical courses at UTC on a consistent basis, something I have done ever since.

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Force Waves in PileIn 2011 I started my PhD in Computational Engineering, which is yet another engineering discipline.  But both advanced degrees had one thing in common: they concerned pile dynamics, and that brings us to the marriage of mechanical and geotechnical engineering.  It’s worth noting that E.A.L. Smith was Raymond’s Chief Mechanical Engineer, before George Goble came on the scene.  Pile dynamics in any form involves things moving and moving fast, and civil engineers in general don’t find this very congenial.  It’s an interdisciplinary field, one where mechanical engineers–and even equipment people–can make serious contributions.

Upon completing my PhD in 2016, my first new teaching assignment was the Fluid Mechanics Laboratory.  This came as a shock to some, but things have worked out, and in any case an understanding of fluid mechanics is essential to geotechnical and mechanical engineer alike.  But ultimately, as so many things are in academia, the full-time appointment (which many have pestered me about since I got my PhD) came from the Mechanical Engineering department due to internal considerations of the College of Engineering and Computer Science.

In going through all of this there’s one trend to be noted that also ties this into Rimsky-Korsakov’s story: the growth of the importance of formal education in the construction industry.  In his case his conservatory experience didn’t endear him to some of his compositional colleagues, who were worried that European “formalism” would spoil the result.  When I came into the family business in the late 1970’s many of our customers had little if any formal education beyond high school.  Like some of the “Five” they accomplished great things.  Today however the educational level of the construction industry–offshore and onshore alike–has risen, and has changed the nature of customer relations in a positive way.

Unlike many I’m not the first in my family to go to college.  However, my people didn’t have a problem starting college: it was finishing it that was another story.  When I completed my first degree is was the first completion in my family in sixty four years!  The MS and PhD were without precedent, at least on my father’s side.  While I am a strong believer that we build on what has gone before, we need to go beyond that, and an education is a way of achieving that result.

I am grateful for UTC’s confidence in me and in particular that of the department head (and my PhD advisor) James C. Newman, III.  My teaching geotechnical courses will continue, as will my contributions to this site.  Stay tuned.

 

Posted in Pile Driving Equipment

Pile Buck Ads 4: Link Belt Diesel with a Mandrel

The fourth in our series on the ads which Pile Buck allowed vulcanhammer.net to run was this shot of a Link Belt 520 driving shell piles using the Vulcan Expanding Mandrel.   The mandrel’s history and shell piles in general are discussed here.

The Link Belt 520 is an interesting story in itself.  The diesel hammer was first developed in Germany by Delmag.  After World War II, the technology was seized as Alien Property and licensed to the Syntron concern.  They made two key changes to the diesel hammers.  The first was to use a true atomizing injection of the fuel (as opposed to the splash system common to most diesel hammers then and now) like a conventional diesel engine.  The second was to put a “bounce” chamber on top, basically a compressed air chamber to store energy on the upstroke, which was then put back into the ram during the downstroke.  This increased the blow rate and shortened the stroke.

The benefits of atomized injection were and are not clear; in some cases the Link Belt hammers were found to stop the ram before it struck the anvil, thus the hammer never impacted!  The bounce chamber mystified many engineers and inspectors in the day, but the concept was adopted by IHC for their hydraulic hammers in the 1980’s.

The Syntron hammer was sold to the crane manufacturer Link Belt, who in turn sold it to International Construction Equipment in the late 1970’s.  They still manufacture diesel hammers but they have changed the concept of the hammer somewhat since then.

You might not think that geotechnical engineering would have anything to do with the Apollo 11 mission that put the first humans on the surface of the moon, but you would be wrong. The landing pads of the lunar excursion module (LEM) had to act as footings on the surface of the moon. If they […]

via Geotechnical Engineering on the Moon? 50th Anniversary of Apollo 11 Landing — GeoPrac.net

Geotechnical Engineering on the Moon? 50th Anniversary of Apollo 11 Landing — GeoPrac.net

Posted in STADYN

STADYN Wave Equation Program 11: Application of the STADYN Program to Analyze Piles Driven Into Sand

The newest update for the STADYN research project is available:

Application of the STADYN Program to Analyze Piles Driven Into Sand

The abstract is as follows:

Abstract: The STADYN program was developed for the analysis of driven piles both during installation and in axial loading. Up until now the test cases used were in predominantly cohesive soils. In this paper, the expansion of the program’s use into predominantly cohesionless stratigraphies has required consideration of two important factors. The first is the difference between strain-softening in clays as opposed to sands, and additionally static vs. dynamic strain effects. This requires a review of the whole concept of the “magical radius” for pile elasticity. The second is the effect of dilatancy on the response of the pile to axial loading. Both of these are discussed in this paper, and test cases are presented to illustrate the application of the program to actual driven piles.

It can also be found on Researchgate.