About that “Warrington Method” For Vibratory Pile Drivability

Every now and then something comes up that you really didn't expect. That took place with a paper published this year cited "W.J. Lu, B. Li, J.F. Hou, X.W. Xu, H.F. Zou, L.M. Zhang, "Drivability of large diameter steel cylinders during hammer-group vibratory installation for the hong kong–zhuhai–macao bridge," Engineering (2022), doi: https://doi.org/10.1016/j.eng.2021.07.028." (You can … Continue reading About that “Warrington Method” For Vibratory Pile Drivability

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The Paper “Vibratory and Impact-Vibration Pile Driving Equipment” Cited

It's happened again: the paper "Vibratory and Impact-Vibration Pile Driving Equipment" has been cited by Mohammed Al-Amrani and M Ikhsan Setiawan in their paper "Prefabricated and Prestressed Bio-Concrete Piles: Case Study in North Jakarta." The abstract of their paper is here: In this research, we will talk about Prefabricated and Prestressed Concrete piles in general and … Continue reading The Paper “Vibratory and Impact-Vibration Pile Driving Equipment” Cited

Checking the Soviets: The Life of the Bearings

The last of our series on "Checking the Soviets" will deal with the roller bearings for the S-834. Roller bearings, be they spherical or cylindrical, are an important part of vibratory pile driving equipment, although for Vulcan's machines cylindrical bearings were the rule. The bearings (#4 in the diagram above) were GOST 5721-57 3614 bearings. … Continue reading Checking the Soviets: The Life of the Bearings

Checking the Soviets: The Long and The Short of It in Beam Analysis

In the last post Checking the Soviets: Determining the Bending Moment and Stress, and the Parallel Axis Theorem, we looked at a section which was represented to act as a beam. We learned that, if that's true, then the way to reduce stresses isn't just to add material, but to add it judiciously. In this section … Continue reading Checking the Soviets: The Long and The Short of It in Beam Analysis

Checking the Soviets: Determining the Bending Moment and Stress, and the Parallel Axis Theorem

In this section we'll discuss the bending moment of the section which connects the two rotors. It's worth noting that, from a vibratory operational standpoint, the two sets of rotors and eccentrics and self-synchonising, which means that, as they rotate, the amplitude of the vibrations synchronise the rotations. This was applied to vibratory equipment by … Continue reading Checking the Soviets: Determining the Bending Moment and Stress, and the Parallel Axis Theorem

Checking the Soviets: Determining the Bending of the Shaft

In our last post Checking the Soviets: The Strange Case of the Spring Constants we discovered some discrepancies in the design of the springs which, although essentially correct, were hard to explain given the information furnished. In this analysis an entirely different problem is encountered, one which is more familiar to practicing engineers. The problem at … Continue reading Checking the Soviets: Determining the Bending of the Shaft

Checking the Soviets: The Strange Case of the Spring Constants

Now that we have established the basic parameters, we need to move on to the spring constant calculations. Here we run into some things that frankly don't make a lot of sense, perhaps the reader can help to resolve the dilemmas. The original calculations are here. Let's start by looking again at the basic impact-vibration … Continue reading Checking the Soviets: The Strange Case of the Spring Constants

Checking the Soviets: Finding the Frequency and Establishing Basic Parameters

In our last post Checking the Soviets: A Tale of Two Cities we described the underlying institutions that designed and built impact-vibration equipment. Henceforth, based on this post we will refer to the two groups as the "Moscow" and "Leningrad" groups, to save the reader having to deal with the Cyrillic alphabet soup that Soviet institutions … Continue reading Checking the Soviets: Finding the Frequency and Establishing Basic Parameters

Checking the Soviets: A Tale of Two Cities

In our last post Checking the Soviets: Determining the Eccentric Moment, we looked at a specific calculation of the eccentric moment of an impact-vibration hammer. Before we get further into this topic, it would be good to pause and give some background on how the Soviets developed the impact-vibration hammer. Once it got out of its … Continue reading Checking the Soviets: A Tale of Two Cities

Checking the Soviets: Determining the Eccentric Moment

This is the first in an aperiodic series on design calculations for a piece of experimental Soviet construction equipment, in this case an S-834 impact-vibration hammer. A more complete history of these machines (a co-author was one of the designers) is here. We're going to compare the calculations originally done on these machines with what … Continue reading Checking the Soviets: Determining the Eccentric Moment