Punching action that drives more piles

Another classic Vulcan ad, this one appeared in the 2 December 1926 edition of Engineering News-Record. It hits (sorry!) on one of Vulcan’s favourite themes, namely that of “heavy ram-short stroke,” which was Vulcan’s design philosophy for most of its existence (or at least until the 560.)

The ad explains the superiority of this concept in this way:

Where the velocity of the hammer at the moment of impact is too high or the ram too light, much of the force of the blow is absorbed within the pile. The driving force is spent before the inertia of the pile can be overcome and the pile begin to move.

To be honest I would explain this differently now. We should note that the “light ram-long stroke” hammers Vulcan was competing with at the time were mostly drop hammers, whose strokes were considerably longer than the Vulcan #1 and #0 series hammers. Especially with cushionless impact, the force at the pile head–and the pile head peak stress–increases with impact velocity. Higher pile stresses, although necessary to some degree to transmit the impact force to the soil, can result in energy dissipation due to plastic deformation, a phenomenon that can be easily seen with pile head brooming. This energy is turned into heat and does not make it to the soil or move the pile.

As far as concrete piles such as is shown in the ad are concerned, the situation is more complicated, but as a general rule it is still easier to control pile stresses with a lower ram velocity at impact. It’s also worth noting that Isaacs’ classic paper on wave propagation in concrete piles–with its analysis of pile damage at low blow counts–was five years in the future at the time of this ad.

Another interesting claim is that, with Vulcan hammers, “none has ever worn out.” Vulcan’s customer base was certainly working on disproving that claim. The oldest Vulcan hammer was a little less than forty years old at the time of the ad; we’ve documented hammers as old as 120 years still in use and in need of parts.

As was the case with other Vulcan ads of the era, the two dealers of Woodward Wight (New Orleans) and Harron, Rickard and McCone (San Francisco) are listed.