Vulcan’s Blow Count Specifications

The durability and longevity of Vulcan pile hammer is something that is seldom replicated in just about any other manufactured product.  Since pile driving is self-destructive on the equipment, this is a remarkable achievement, but it should be tempered by the fact that it’s possible to render a Vulcan hammer inoperable by the way it’s used.  There are many things that can make this happen–inadequate or nonexistent hammer cushion material or lubrication to mention two–but the one thing that Vulcan decided to include in its warranty was the blow count specification.

Recording the blow count–the number of hammer blows per inch, foot or metre of pile advance–is virtually universal on pile driving jobs.  The dynamic formulae basically translated blow count into pile capacity.  While anyone familiar with pile dynamics understands that blow count is a crude measure of the response of a pile to impact, including a blow count specification is a good first measure of both the advance of the hammer and also how much energy is being returned to the hammer, which is a case of hammer damage.

BLOWCNT
Blow count-resistance graph, developed by Vulcan in the early 1990’s as part of its effort to educate state and federal agencies on the basics of pile driving. As the blow count increases, the amount of SRD (soil resistance to driving) increases, but at a progressively slower rate. This indicates that simply increasing the blow count is a “diminishing returns” proposition, destructive for hammer and pile alike.

High blow counts indicate that more and more of the energy was going back into the hammer rather than into the pile, thus increasing the danger of hammer damage.  They also indicate that pile top stresses increase with higher blow counts, as the movement of the pile to mitigate the maximum impact force decreases.  Thus high blow counts just to get the pile to tip elevation without considering changes in hammer or basic drivability considerations is a losing proposition.

Starting in the late 1970’s, Vulcan voided the warranty on its hammers if the blow count exceeded 120 blows/foot.  It’s interesting to note that Vulcan never made its specification in blows/inch.  This was true for its onshore hammers; however, for its offshore hammers it was forced by circumstance to increase the hammer refusal criterion as follows:

BLOW COUNT SPECIFICATION 1

Vulcan hammers are designed to withstand a continuous driving resistance of 120 blows/foot (400 blows/meter). In addition to this, Vulcan hammers will withstand refusal driving resistance of 300 blows/foot (1000 blows/meter) for five (5) consecutive feet (1500mm) of penetration. Any resistances experienced in excess of these are beyond rated capacity and will void the warranty. This definition is not an exclusive definition of excess of rated capacity and other criteria may apply.

1 Specification applies to all Vulcan offshore hammers, not just those listed in this catalog.

This was drawn from the API RP 2A specification, which was discussed relative to pile stick-up.  An elevated refusal blow count specification was justified by two things.  First, the offshore hammers were more robustly built than the Warrington-Vulcan hammers which made the company famous, as they were derived from the Super-Vulcan hammers.  Second, the remoteness of offshore job sites made high blow counts a necessity, as bringing a larger hammer to the job was frequently impractical.  (Improved methods of drivability predictability lessened the possibility of this happening.)

Blow count limiting warranty specifications are not an absolute method to prevent hammer abuse, but they’re a good start, and Vulcan used them to the advantage of itself, its end users and the owners of the projects where Vulcan hammers were used.

Driving Piles with Stub Leaders and a Template

The best known setup for pile driving equipment is a crane and a set of full-length (of the pile and hammer) leaders, attached to the crane in a variety of ways.  But another alternative is to use a “stub” leader, i.e., one that is very short, and a template to align, position and guide the pile.  This is traditionally associated with steel piling, so we’ll look at this first.

For these hammers the platform itself is the template, the piles are driven from the top through the legs.  Most conventional platforms had angled legs so the hammers almost invariably drove on a batter, which gave rise to the “stick-up” problem, more about that below.

But using stub leaders and a template isn’t restricted to steel piles; it has also been done on concrete piles, as can be seen below.

From a contractor’s standpoint, handing hammers in stub leaders requires a considerable level of skill from the crane operator, but the weight savings and ability to handle the hammer in difficult situations makes the use of stub leaders, when possible, a very attractive option.

Engineering Aspects of Stub Leaders

From the photos above, you can see that piles can be driven with stub leaders either plumb or on a batter.  Plumb piles are not much different with stub leaders than with conventional leaders: the key is to have the hammer straight and square on the pile, which means that the leader setup should be balanced to hang straight and side forces on the hammer be avoided.

With batter piles, since the offshore industry used them (and still does) intensively, the most complete specification for such piles is the American Petroleum Institute’s RP2A specification.  With stub leaders the pile basically supports the hammer during driving, and the hammer in turn loads the pile with both the impact loads and the static load of the hammer assembly, which in turn acts both parallel and perpendicular to the axis of the pile.  Basically there are two important engineering aspects to configuring driving batter piles with stub leaders on a template:

  1. Column buckling due to the weight of the hammer acting on the axis of the pile.
  2. Beam loading of the hammer due to the component of the weight which acts perpendicular to the axis of the pile.  This creates a cantilever beam with a maximum bending moment at the template.  Obviously the weight of the hammer assembly (along with the weight of the pile) will induce bending stresses.  These stresses are both tensile and compressive, and both are important to the structural integrity of the pile during driving.  The template must also be designed to handle the loads and moments on its structure.

With steel piling, the combined weights of hammer assembly and pile limit the permissible length of the “stick-up” of the pile.  Steel piles are easily spliced and added on to, so piles which are much longer than the stick-up can be drive.  (Piles which are much longer than practical lengths of conventional leaders can be driven as well.)  With concrete piles, these can be splices but there is less flexibility and less resistance to bending moment with splices, which limit the possibilities of driving these with stub leads on a batter.  (The ability or lack thereof of concrete to withstand bending stresses also complicates the situation.)

One more important point: the weight of the hammer assembly cannot generally be assumed to be at the pile head, but above it.  That’s why the center of gravity information is so important for offshore driving, which led to Vulcan tips such as this.

Stub leaders combined with templates is an attractive option for driving piles, but proper engineering and construction procedures must be followed for successful results.

 

Vulcan’s Most Famous Sheet Piling/Extractor Photo

The photo above, dating from 1949, shows a worker tightening the bolts on the connecting links of a Vulcan extractor to the top of a prepared sheet piling in preparation to impact the sheeting upwards and take it out.  This photo was used for many years in Vulcan literature, including Vulcan Bulletin 71B.  (Note: don’t try this now without a safety belt and other safety equipment for the worker!)

The project it was on was in familiar country to Vulcan: it was for the Calcasieu River Bridge between Westlake and Lake Charles, LA.  The owner was the State of Louisiana Department of Highways.  The contractors were Kansas City Bridge and Massman Construction, still a user of Vulcan and Conmaco equipment.

It’s also interesting because it’s similar to the “sheet pile setter” logo that Pile Buck has used for many years in its own logo and advertising.

Vulcan #1 Hammer in Ohio

Below are three photos taken of a Vulcan #1 hammer in Mentor, Ohio.  It’s in fixed leaders with a moonbeam-style spotter.  The hammer was made in Chicago, which means that it’s probably older than sixty years.  Thanks to Ken Foster for sharing these great photos.

Vulcan at the Circus: the 1200A Extractor

Vulcan had introduced its extractor line in the late 1920’s, after several design iterations.  They had proven successful; for example, they were used in the construction of the original Tennessee Valley Authority systems of locks and dams.  But, as is often the case with pile driving equipment, what contractors wanted could be summed up in one word: bigger.

In the extractor field, they got what they asked for: in 1954 Vulcan introduced the 1200A extractor, the largest in the and larger than any of the MKT “E” type extractors, their main competitor.  To debut the line Vulcan did something completely different with its literature: it used a circus theme to emphasize its large size.  You can see this below.

This may look silly today, but these days when we emphasize size, it’s completely different…when Vulcan came “down to earth” around the time it moved to Chattanooga, they put out this sheet, which shows all of the sizes and their specifications.

Mating Pipe Piles to Pipe Pile Caps

Pipe pile caps have been around as long as pipe piles, but mating them to a pile hammer via a pipe cap may be new to some users.  The diagram above (which, as you can see, dates from 1931) shows how this is done.

The cross-section shows three diameters of pipe piles mating with a pipe cap.  Pipe caps typically have steps to mate with more than one size of pipe pile.  It’s also possible to drive pipe caps “flat face” (with no steps) but you lose the alignment assistance of the cap when you do.

The outer two pipes mate with “male steps,” those which face the inside diameter of the pipe.  It’s necessary thus to know the ID of the pile, which usually means the OD and the wall thickness.  A little clearance is allowed to make mating simpler and to take into account the fact that pipe pile isn’t always perfectly round (especially at the ends, where it gets bent.)

On the small onshore caps, the steps are typically straight.  On the offshore caps, Vulcan typically put in a draft angle to make stabbing the pile easier.

With caps with multiple steps, it’s possible for the steps to interfere with each other because the diameter of one step is too small to accommodate the OD of the pile below it.  To avoid this problem requires some layout before the cap is machined.

Male pipe caps can be used with wall thicknesses thinner than originally intended with the use of welded shims.

The inner pile mates with the “female” portion of the cap, i.e., the OD of the pile.  This eliminates the ID mating problem but requires a completely different cap design.

Some other information is shown below.

D100178
Vulcan’s choice of pipe cap design deserves some explanation. Below is a diagram of the three basic types of pipe caps in use, both during the heyday of Vulcan offshore hammers and now. Male Caps (left) were the standard Vulcan configuration. The cap is stepped for different pipe sizes and is fitted to the I.D. of the pipe. To align the leads and the pile (especially important with the batter piles common offshore) the pipes were passed through a stabbing bell (at the bottom) which itself was stepped to the O.D. of the piles. The arrangement was preferred with Vulcan’s customers (especially those in the Gulf of Mexico) because the cap is easy to modify and shim for different size piles and the stabbing bell is easy for the crane operator to thread the hammer assembly over the pile for driving. Female Caps (centre) was most common with the Menck hammers. All of the steps were mated to the O.D. of the cap. Although mating it to piles was more straightforward, since the maximum plate moment of the cap was in the centre, the thicker centreline of the male cap was an advantage. Flat Face Caps (right) were preferred by the diesel manufacturers such as Delmag (and later IHC and Pileco.) Since there are no alignment steps on the cap, all of the alignment takes place with the adjustable keys under the cap facing the O.D. of the pile. (It’s better to have two sets of keys than the one shown.) Although the cap is much simpler, the carrier required for the cap and keys can be complicated to produce.

Pulling Adapters for Vulcan Extractors

Vulcan pile extractors were largely designed to extract sheet piling.  The standard connection had two (2) or three (3) holes that needed to be burned into the sheeting.  While this provided a very durable connection, it was time consuming and is not really applicable to piling such as wood piling.

Above is a diagram, taken from Vulcan’s literature around 1960, showing various types of pulling adapters for piling other than sheeting.  In addition to these there were two other types of connections that were used on Vulcan extractors:

  1. The Heppenstall tongs, which were similar to the clamp used by the Nilens extractor.
  2. The Wood Pile Puller.

The Best Way to Celebrate Your 120th Birthday is With a New Slide Bar Part

On our Engineering at Vulcan page, we posted this general arrangement of the Vulcan #2 dated 1887.

2-Steam-Pile-Hammer-1887
The first extant layout of the Vulcan #2 Hammer, dated 9 February 1887. It’s probably the first extant layout of the Warrington-Vulcan hammer. Until about World War I, it was common practice for Vulcan to lay out the general arrangement and then the shop produce much of the hammer from just that drawing. It’s an indication of both the skill and the decision making ability of those actually producing the product, and also probably of the involvement of those doing the design work.

Little did we suspect that we’d need that drawing, but then these photos from Crofton Diving of Portsmouth, VA, arrived:

The hammer in question is Vulcan S/N 116, originally sold to the Florida East Coat Railroad (not far from the West Palm Beach facility) in 1897.  The distinctive “open” slide bar design was changed about that time to what is on virtually every Warrington-Vulcan and Super-Vulcan hammer made since.  Vulcan Foundation Equipment  was able to make the spare parts Crofton required from the original detail drawings.

“Planned obsolescence” wasn’t the Vulcan way in 1897 or afterwards, which is why a 120-year old product is still driving pile and being useful to the contractor.

DSCN2960
Crofton Diving at work: the Crofton I barge driving piles at a marina, Norfolk, VA, 2009.  The pile driving rig is using swinging leaders.

General Arrangements and Assemblies

d35373One of the typical information items Vulcan would send out would be the “general arrangement” (or assembly, to use the Raymond terminology) of a hammer, or a sub-assembly such as a capblock follower. These were also included in the offshore field service manuals. Sometimes they would feature the specifications of the hammer. They are useful for basic clearance and other dimensions or to understand the basic layout of the machine.

Some of these were put in data format. We feature for download some collections of these as follows:

  • Vulcan 020 Offshore Hammer Specification Sheet. Not a general arrangement per se, but a specification sheet (in US and SI units) along with parts of the general arrangement on the back. These were issued in the 1970’s and were very popular for many years.
  • Vulcan 040 Offshore Hammer Specification Sheet.
  • Vulcan Offshore Hammers
    • Auto-Jack Cable Tensioning Device for most Vulcan offshore hammers
    • Vulcan 535 Hammer, 54″ and 80″ Jaws (similar to the 530)
    • Vulcan 530/535 Capblock Follower Assembly (80″ Jaws)
    • Vulcan 560 Hammer
    • Vulcan 5110 Hammer
    • Vulcan 5100 Capblock Follower Assembly
  • Vulcan/Raymond Hammers
    • Vulcan 513 Hammer
    • Vulcan 515 Hammer
    • Vulcan 517 Hammer
    • Vulcan 525 Hammer
    • Vulcan/Raymond 60X Hammer, with and without Vari-Cycle II
  • Vulcan/Foster Vibratory Hammer. Vulcan manufactured L.B. Foster vibratory hammers during the 1990’s on a “private label” basis. These are the general assemblies for the 1050 and 4200.

Some of our general arrangements are in image format; we present some of them below.

We also have an extensive collection of these (including the specification sheets) in other “traditional formats.” If you would like to contact us about obtaining these, click here. We also have extensive information in our Vulcan Data Manual.

About Those Manhole Covers…

Vulcan-Bulletin-20Vulcan received inquiries from all over the world about its products.  One call Vulcan received until the end was about manhole covers.  Although Vulcan’s response was always the same (it didn’t make manhole covers) the fact was that at one time Vulcan did make these humble but ubiquitous products.

On both ends of the twentieth century Vulcan’s letterhead stated that it manufactured “Machinery for Public Improvements.” Although the pile driving equipment certainly fell into that category, it wasn’t the only product line meant for consumption by the public sector.  That included many of its custom products, including the bridge gears it produced for many bascule bridges in Chicago and other areas.  That also included the manhole covers, or more formally designated “Curbs and Covers: Manhole and Catch Basin.”

These items appeared in Vulcan’s general catalogues in the 1910’s and 1920’s.  Eventually when these gave way to the product bulletins of the late 1920’s and beyond, Vulcan produced one for the manhole covers, its Bulletin 20, issued in 1942 (cover shown here, bulletin can be downloaded here.)

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The key to this business was having your own foundry, and Vulcan’s went away in the late 1940’s.  Around that time the manhole covers went out of Vulcan’s offerings.  Unfortunately it took a long time for the word to get around, and Vulcan continued to get calls about these for the duration of the company’s operation.  Part of the problem was that there was (and is) more than one “Vulcan Iron Works.”  Vulcan was the god of the forge in Roman mythology; it was a common name for heavy manufacturing in the nineteenth century, an age of iron, steel and classical learning. At least one additional Vulcan Iron Works produced manhole covers, something that added meaning to the word “discovery” at litigation time.

Probably the vast majority of the manhole covers produced by the Vulcan Iron Works discussed by this web site are gone from their proper place.  (One that didn’t is at the top of the page.)  Had Vulcan been swum with the tide more than it did, it probably would have outsourced the manhole covers abroad.  But it didn’t, leaving one part of its product line well in its wake.