NPO VNIIstroidormash: Soviet Construction Equipment Technology

On this site I have posted several articles on Soviet (and after that Russian) pile driving equipment, such as diesel hammers, concrete pile cutters, and vibratory and impact-vibration hammers. These are very specialised topics, even by construction industry standards; here I want to present some photos of more general interest to you heavy equipment fans. The Soviet Union was known for its commitment to heavy manufacturing and construction equipment like this is certainly a big part of that.

NPO VNIIstroidormash is the Soviet name for the Moscow-based institute which designed and tested the equipment shown below. The name means the All-Union Scientific Research Institute of Construction and Road-Building Machinery. It was put together in 1975, and survived past the end of the Soviet Union in 1991 as a share society, i.e., a privatised corporation. In addition to the pile driving equipment which got me involved with the organisation, it designed many other types of equipment, and the best way to show this follows, from their catalogue produced around 1986.

laser-levelled-bulldozer
DZ-110A-1 Bulldozer with laser-beam steering and control system. Surface-working accuracy +-5 cm at 10-400 mm distance from the laser source. Such a set-up is common today; at the time it was not.
laser-levelled-scraper
Similar, laser-levelled concept with a DZ-122A-13 motor grader.
eo-4125-excavator
EO-4125 excavator. The excavator is probably the single most versatile and important earth moving machine on a construction site. This one sported servo-controlled valves, which makes current excavators easier to use than their older counterparts.
excavator-with-special-attachment
Excavators are versatile in that things other than the usual bucket can be mounted on the boom. In this case, the MTP-71A excavator has an extended backhoe used for large swing radii and canal digging. It’s mounted on rubber tyres (the one above is on tracks) for softer soils; it’s also easier to transport on roads. To increase the effective counterweight it sports outriggers.
eo-3323-excavator
EO-3323 excavator, also mounted on tyres with outriggers. The red bucket on the end has a capacity of 0.75 cu.m.
12-5-ton-crane
Turning to cranes, this is a 12.5 (metric) ton hydraulic truck crane. Very useful for light lifting, they’re fairly common on construction sites and other places.
40-ton-truck-crane
40-ton truck crane, another versatile tool.

Our business used these often for the assembly of our larger hammers, but sometimes things didn’t go according to plan.

250-ton-crane
250-ton crane. For really heavy lifts, Vulcan could have used this for its biggest products. Cranes such as this were used in the early 1980’s for the modification of its biggest hammer.
vibration-roller
DM-476 vibration roller for compaction. These machines are not really intended for deep compaction of soils but surface smoothing, which is necessary when building roads and airfields.
grader
DZ-140 motor grader, used for final levelling of roadways before smoothing and paving. The blade is 4.8 m long.
skid-steer-loader
TO-31 skid steer loader, better known on American jobsites as a “Bobcat” after the popular American brand. Maybe they should have named this a “Siberian Tiger.”
bulldozer-ripper
A bulldozer-ripper. Most people connect bulldozers with moving soil, but this one is designed to break up rock for removal.
vniistroidormash-computer
Computer aided design, 1980’s style: VNIIstroidormash’s computer room.
vniistroidormash-library
VNIIstroidormash’s library.
vniistroidormash-female-cross-country-ski-team
VNIIstroidormash’s female ski team.

Vulcan first connected with the Institute in 1988, and our contacts continued for the next six years. Sometimes things got strange but we discovered an organisation that put out some very good designs for construction equipment. Unfortunately the Soviet manufacturing organisation was not up to proper quality control, especially in the civilian sector, and that weakness was one of those which ultimately brought the Soviet Union down.

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Half a Million Roubles. Is it Enough?

In early 1994 I went to Russia for the purpose of visiting a factory in Bryansk, which is located at the meeting point of Russia, Belarus and Ukraine. This was not a factory producing high tech military hardware, but something more prosaic but important for our modern world: diesel pile driving equipment, used in the construction of roads, bridges and buildings.

Below: a YouTube video of the inside of this plant.

soviet-diesel-hammer-exhibi
Soviet diesel pile drivers on display. Did our intelligence services mistake these for a new missile technology?

These were the days when the Russian Mafia reigned supreme, so we had to be careful. The plan was for me and my representative to cross Moscow via car and metro to the Moscow Kievskaya train station, board for a six hour “overnight” train trip to Bryansk, spend the day there, and return as we came to Moscow. Except for our plans for avoiding the criminal element, this wasn’t a very difficult trip.

So we made our preparations. No US cash, no credit cards. I even switched my wedding band to my right hand. We were planning on travelling light, but we had to have some spending money. So, as we prepare to leave, my representative whips out a wad of Russian cash and asks me, “Half a million roubles. Is it enough?”

I was boggled by the question. Not even family trips with my mother to the Ritz-Carlton cost half a million. But here the currency had collapsed with communism; the exchange rate was about 1300 roubles to the US dollar. So we were only talking about US$385, which was a reasonable sum considering that much of our travel (especially by train) was subsidised by the government.

Some of you reading this live in a place where the currency is parcelled out with many zeroes. But it’s interesting to note that, to my knowledge, no currency started out that way. If we look at major currencies today, we see that all of them are either “substantial” in their value (dollar, euro, pound) or were at one time (yen, and of course the rouble itself.) But there is a greater lesson here.

If Islamicism has done one thing, it has put monotheism on the front page of the news, whether the secularists like it or not. (And they usually don’t.)  This is something, of course, that Islam has in common with Christianity and Judaism. But there are still many who believe that there are many gods. The most important representative of this is Hinduism, where literally millions of gods are resident and require worship of some kind.  Mormonism for its part is more worried about its adherents becoming gods rather than worshiping a polytheistic system of same.

Then, of course, we have secular systems of “gods” which do not have spiritual divinity but have divine importance to their adherents.  We think of people who are focused on their houses, their motor vehicles, their jobs, etc.  These are pursuits that can pull you in many directions, to say nothing of run your finances down.

The central problem with any system of belief that affirms the existence of more than one God is this: the more “gods” there are, the less meaningful the whole idea of deity becomes. Like the roubles we took to Bryansk, there may be many of them, but they’re not worth very much. Both Russian roubles and Mormon gods are the product of the same process: too many of each were “created” for the intended purpose. Religions such as New Age and Mormonism attempt to exalt humanity by debasing divinity, but they end up debasing both. As with currencies, we are better off with one God who is worth it all than many which are, individually and frequently as a group, worth very little. The promise of divinity doesn’t look all that good when seen in this light; it is a mirage that vanishes as we approach it.

quote:


Hear, O Israel: The LORD our God, the LORD is one. Love the LORD your God with all your heart and with all your soul and with all your strength. These commandments that I give you today are to be upon your hearts. Impress them on your children. Talk about them when you sit at home and when you walk along the road, when you lie down and when you get up. Tie them as symbols on your hands and bind them on your foreheads. Write them on the door frames of your houses and on your gates. (Deut 6:4-9 from New International Version)


Socialist states love to trumpet their own successes, real or just propaganda. The collapse of the rouble left just about everyone in the Russian Federation with more than a million roubles (about US$770 in early 1994) of net worth. So I declared to my representative, “Seventy years of socialism, and everyone’s a millionaire!”

His response: “It was their greatest achievement!”

For more information click here

Who’s this idiot? That’s me!

Our family business’ first trip to the then Soviet Union was an interesting experience. Our objective was to sell the Soviets (as they were called then) our offshore pile driving equipment for their offshore oil production work. Their idea was to get us to sell their diesel pile driving equipment and other Soviet technology in the U.S. (We eventually got there, but that’s another story altogether.

zagorsk1Needless to say, this was a recipe for confusion. One good thing that came out of it was our visit to the Monastery of Trinity-St. Sergius in Zagorsk, the administrative centre of the Russian Orthodox Church.

We did finally meet with the offshore oil people. It was strange too; when the babushka receptionist asked where we were from and we told them we were from the U.S., she jolted upward in her seat and exclaimed, “Oh, my God!” (this in an atheist state!)

Finally we had our closing meeting with our Soviet counterparts. This was during the age of perestroika, which simply means restructuring. This ministry was doing its own shuffle, so the chief negotiator unfurled the new organisation chart for the ministry. He spent a great deal of time going through everyone’s new title and position. Our agent got impatient with this presentation, so he thrust his finger at the centre of the chart and demanded, “Who’s this idiot?”

“That’s me!” the answer came back.

It doesn’t take being in a socialist organisation to make us feel that we’re “lost in the shuffle,” just another cog in the machine or just another “idiot” working in an structure that neither knows or cares whether we stay or leave. We get to the point where we look at ourselves and life in general in this way.

But that wasn’t God’s plan for us. We have a God who loves and cares for us, who created us and had a purpose for us from the beginning (“negative infinity,” as we say here.) Just because others who have their own purposes–if they have any clear objective at all–try to define us as part of their machine doesn’t mean that the God of the universe agrees with their assessment. He does not and neither should we. If we make him first in our lives, we will find his purpose for us and then we will never again be “this idiot.”

For more information click here.

He is Prepared to Sign Anything

Concrete Pile CutterOne of the most complicated transactions I have ever been involved in during my years at Vulcan was the purchase of the patent rights for a Russian concrete pile cutter (shown at left.) The patent had around a dozen inventors and two research institutes, spread out from Moscow to Vladivostok. The sheer logistics of getting everyone to agree to this, to say nothing of the financial considerations, made it a daunting task.

After six years of work on it we had actually made quite a lot of progress, but the Deputy Director General of the main research institute was trying to hold out for more money. Since the market for these things is pretty limited, we had to be careful.

At this point the Russian government sponsored a Russian technology exposition in Washington, DC, and the institute was one of the exhibitors. They sent their Director General; we thought it would be a good time to make some progress without the expense of another trip to Russia. So I went to Washington, was met by my translator, and we set out to have a meeting with the Director General.

On the way we stopped by the hotel room which the institute’s people were using as a headquarters. It was a mess; clothing and trash were piled everywhere, vodka bottles being the most prominent. Evidently these people were having quite a time during their trip to America.

We got to the exhibit hall and managed to pull the Director General aside for a meeting on the patent. In preparation for this meeting, I had prepared a “protocol” (we usually call it a “letter of intent” in the U.S.) which outlined what was for us an initial negotiating position. So I presented this and asked the Director General what he was prepared to sign to conclude this agreement.

At that, my translator looked me straight in the eye and said, “He is prepared to sign anything.” Needless to say, I wasn’t prepared for this; I was used to a lot more “horse trading” in negotiations, particularly with people outside the U.S. But sure enough, he was; he signed the protocol. Back in Moscow, his deputy was enraged at this, but there was nothing he could do; the negotiations were completed and we obtained the patent assignment.

We live in an age where people are said to be deceived by all kinds of “isms”: moral relativism, secular humanism, post-modernism, and the like. But having been in the real world for too long, I like to look at things a little differently. The problem with people today is that, after years of excessively rapid upward social mobility, blistering technological change, and relentless manipulation by those who own and operate the society, they are, like our Director General, prepared to sign anything, to go along with anything so long as their lives go on as they have, no matter what the long term cost is to themselves.

“For a time will come when people will not tolerate sound teaching. They will follow their own wishes, and, in their itching for novelty, procure themselves a crowd of teachers. They will turn a deaf ear to the Truth, and give their attention to legends instead.” (2 Tim 4:3-4) This is where we’re at, with the disintegrating families, eroding human rights, and the growing consumer debt which is turning a society of owners into a society of renters, at the whim of those who control the financial destiny of the nation. Christianity, which takes a definite stand on many issues, is looked on with hostility as a menace to the stability of this house of cards, proclaiming as it does an ultimate authority beyond the state.

But there’s always a payoff of some kind in the end. Our Russian inventors and institutes were paid off in U.S. dollars, a valuable commodity in Russia in those days. Those who sign with the rulers of this world have another payoff altogether: “The wages of Sin are Death, but the gift of God is Immortal Life, through union with Christ Jesus, our Lord.” (Romans 6:23) It’s your choice. Are you prepared to sign anything?

Visit to Zagorsk

In 1988, during Vulcan’s first trip to the then Soviet Union, my brother Pem and I were given the chance to visit the Monastery of Trinity-St. Sergius, which was the administrative centre of the Russian Orthodox Church. This is located in the town of Sergeiev Posad, which was called Zagorsk during Soviet times. The trip was arranged by our Russian business hosts (V/O Machinoexport) and our Russian agent at the time, A.A. Titov. The article below was written 20:15:01 4/20/1988 (the day of the visit) with a few corrections in the text and updates at the end.

Background

zagorsk1Christianity was first introduced to Russia from Byzantium (Greek Orthodox) between 860 and 867. At this time Kiev — south of the Chernobyl site — was the capital of Russia. In 957 the regent Olga was baptised in Constantinople; her grandson Vladimir made Christianity the state religion in 988. This is being celebrated this year as the 1000th anniversary of the “Baptism of Russia” and extensive celebrations are being made plans for as a result.

The Russian Orthodox Church is an Orthodox Church, and until 1448 was subordinate to the Greek Orthodox Church in Constantinople. At this time, as the Byzantine Empire was coming to an end with its conquest by the Ottoman Turks, the Russian church took the step of electing its own leader; in 1589 this leader, now residing in Moscow, took the title of Patriarch, making him in theory the equal of the Patriarch in Constantinople and also of the Pope in Rome.

In 1721 the Russian Tsar Peter the Great abolished the Patriarchate and replaced same with the Holy Synod to run the Orthodox Church. This was a council, with its head — a lay official — appointed by the Tsar. This effectively made the Orthodox Church a department of the government, a position it found itself in until the Tsar was overthrown in 1917.

With that overthrow the Church re-established the Patriarchate, but now the greater threat came of course from the Communists, who, following Marx, believe that religion of all kinds is the “opiate of the people” to dull their revolutionary drive, and which will wither away under the advance of “scientific” socialism such as their claims to be. The church’s property was nationalized and many of its clergy was jailed and killed, and parts of the church made themselves into a pro-Soviet type of church, a process that has been repeated with the Catholic Church in Nicaragua. Matters became especially desperate under Stalin, who attempted to destroy all opposition through liquidation in his purges in the 1930’s.

Matters were at their nadir when the Second World War broke out, and when the Germans invaded the Soviet Union the demoralization of the nation was so complete that Hitler nearly succeeded in conquering the country. In its desperation Stalin’s war effort turned to the Orthodox Church and other Christian groups to help with the war effort, to revitalize the people for the war effort. This they did, and in return the Soviet government has granted the Orthodox Church and some other Christian groups limited freedom of existence and activity. The Orthodox Church today runs a precarious balance today; on the one hand it attempts to carry on its liturgical and spiritual activities to nurture the flock in the Orthodox faith, on the other it must to secure its existence meet Soviet regulation and to assist the Soviet government in various activities, such as the promotion of the peace movement in the West, which is a major project of the Soviet regime today.

Outline of the Trip

zagorsk2 Arrived about 1130 with Pem, Alex Titov, and Alexander Tikhanov and assistant Natasha from V/O Machinoexport. Were greeted at Monastery office.

We were first given tour by Father Alexander of several of the churches in the compound. Zagorsk is the administrative centre of the Russian Orthodox Church, founded by St. Sergius in 1337. The Orthodox complex is within the town itself, being a walled fortress, a format dictated by military considerations in past times, similar in concept to missions in our own Southwest such as the Alamo. The last time it was used for military purposes was against a siege by the Poles in the 15th century. These churches, such as the Trinity Cathedral (which contains St. Sergius’ relics), the Dormition Cathedral, the Church of the Holy Spirit, were very impressive. When not in liturgical use, these churches are the site for all kinds of devotions, such as prayers, adorations, and Bible reading, and, in the case of Trinity Cathedral, singing which has an ethereal quality beyond words to describe. Then we returned to office where we signed the guest register, and I wrote congratulations to them for the 1000th anniversary of what they call the “Baptism of Russia”.

After this, we were given tour of the seminary museum by a seminarian. This contains historical articles of the Orthodox church of all kinds and a special section on the life and work of the Patriarch Alexis, who helped bring the Orthodox Church back to life after its near extinction by Stalin. There was a scale model of a large cathedral in Moscow built to commemorate the victory over Napoleon in 1812. Titov asked what happened to it and the seminarian replied “What happened to thousands of other churches in Russia? There is a swimming pool where that one was.”

We then went to the seminary office, where we were greeted warmly by Father Vladamir Kucherjavy, Assistant Rector of the seminary, who then fed us snack. He gave us description of the work of the seminary, and in the process told that full course in seminary was a four year course followed by two year course, similar to our own BA/MA system; however, some went directly to the field after the first four years. This reminded me of our church’s internship program, so I asked Father Kucherjavy if the two were alike. He said yes, and then asked what church I belonged to. I told him that I belonged to the Church of God, that it was started in 1886, that it was the oldest Pentecostal church in North America, but that Russian Orthodox people had had the Pentecostal experience earlier. His first question was whether we were a member of the National Council of Churches or not, and I replied that we were not. I then explained that I knew about the Orthodox people because the founder of the FGBMFI, Demos Shakarian, an Armenian, had had grandparents and parents brought to it by these believers coming to Turkey from Russia. He then reminded us that this year was the 1000th anniversary; I replied that I was appreciative of this event. He said that they were more than that; they were working hard to make the actual celebration a reality this summer, including having to rebuild the seminary’s church after a disastrous fire two years ago. Having seen the restoration, I said that I was impressed with the speed of the work. He said, in effect, that I didn’t know the half of it! He went on to describe his travels in the U.S., which he makes mostly for Soviet sponsored peace groups. We then finished our session and he wished us good bye. I told him that I would tell those officials and such in our church of my visit, as I live in the denominational headquarters city and attend church with these people.

Note: the “large cathedral” was of course the Cathedral of Christ the Saviour, dynamited in 1931 under Stalin. It was in fact rebuilt during the 1990’s, which I discuss in my Easter piece Rising From the Pool. I did present this account to Church of God officials; the church eventually established a legal presence in Russia which it has to the present day.

Soviet S-834 Impact-Vibration Hammer: Calculations, Part II

The introduction to this series is hereThe first installment of the calculations is here.

Calculations of Main Details (Strength
Calculations)

Strength calculations assume that the inertial forces during impact are 150 times those of the weight.

Rotor Shaft

We checked the rotor shaft strength in the optimal mode, i.e., when the impacting force direction formed a 90° angle with the direction of the blow. To simplify calculations consider that the forces act at one point. In the vertical place the shaft is loaded with impact inertia forces from the shaft weight and parts which are located on it.

where Q1 = inertial force from eccentric weight(s) and part of the shaft ahead of the eccentric.
Q2 = inertial force from the part of the shaft under the bearing.
Q3 = inertial force from the rotor weight and the middle part of the shaft.

A diagram of the shaft assembly is shown below.

Figure-1

A diagram of the beam forces in the vertical plane is shown below.

Figure-2

A diagram of the beam forces in the horizontal plane is shown below.

Figure-3

The forces which act on the shaft in the horizontal plane arise from the vibrating forces of the eccentrics.

The reactions in the vertical plane are

The reactions in the horizontal plane are

The bending moment in the vertical plane in section A-A is

In section C-C it is

In section B-B it is

The bending moment in the horizontal plane in Sections A-A and C-C is

and for Section B-B

The sum of bending moments in Section A-A is

In Section B-B they are

and in Section C-C they are

The bending tension is calculated in the same way at all points.

For Section A-A

For Section B-B,

and Section C-C,

The tension in this section will be much less because the calculations do not take into account the force from the rotor shaft. Calculation of the shaft deflection will be done in Part C.

The calculations consider that the shaft is of uniform diameter, equal to 62 mm. In the vertical plane the deflection is equal to

where kg-cm
= axial inertial moment of cross-section of the shaft

E = spring modulus of shaft material = 2,000,000 kg/cm²

The deflection in the horizontal plane is equal to

The total deflection from horizontal and vertical moments is

In reality deflections will be smaller because we did not take into account the rotor forces.

Determination of Tensions in Vibrator Casing

The casing is subjected to loading tensions when the vibrator impacts on the pile cap. As the ram is located in the centre of the casing the critical sections are two perpendicular sections which are located at the planes of symmetry of the vibrator.

Let us determine the moment of resistance of the section which is shown in the drawing of bending tensions in this section, shown below.

Figure-4

This section is weakened by a hole for the ram but this weakness is compensated for by the local boss. So we do not take into account the hole and its boss.

The moment of inertia for the section relative to axis X-X is determined as

where = sum of inertial moments of the separate elements.
= sum of multiplication of squared distances from the mass centre of element ot the axis X-X by the area of the element.

The moment of resistance for this section is

The distance between the axes of the electric motors is mm. So the bending moment is equal to

The bending tension is equal to

Let us determine the bending tensions in the section perpendicular to the axis of the rotors. The section is shown in the drawing below.

Figure-5

To simplify the calculations consider the section of the casing is symmetrical and consists of two circles and two rectangles.

The inertial moment is equal to

The moment of resistance equals to

Let us now determine the bending moment considering that the load from the weight along the axis parallel to the rotor axis is distributed uniformly.

Figure-6

The bending tension is equal to

Spring Deflection Calculation

The maximum force for which spring deflection is required is P = 1000 kgf. The number of spring N = 2. The maximum deformation of the springs is f = 200 mm. The load for each spring is

As the springs are operating in relatively easy (not hard) conditions we can consider the permissible tension equal to 5500 kgf/cm². So the permissible tension per 1 kgf of load is equal to

The necessary spring stiffness is equal to

So we choose the spring with the following specifications:

Average Diameter

Wire Diameter

Hardness of One (1) Turn

Number of Working Turns

Npad = 14.5

Total Number of Turns

N = 21.5

Tension per 1 kgf of Load

A = 11.18

Hardness of the whole spring

So the spring we have chosen meets all of the requirements.

Determination of the Geometrical Configuration of the Eccentrics

Consider that the balanced part of the eccentrics (I and II; see diagram below) cancel each other.

Figure-7

So the coordinate of the center of mass of the rest of the eccentric (in the shape of a sector of a circle) is determined by the equation

The weight of the unbalanced part of the eccentric for a 1 cm thickness is equal to 1.7 kg. The eccentric moment of this eccentric is

The dynamic force of the eccentric is

The angular speed is rad/sec. The necessary eccentric moment of the eccentric is

The necessary total thickness of the eccentrics is

As during the determination of the eccentric moment it was increased a little, consider the thickness of the eccentrics equal to 80 mm.

This configuration of the eccentrics which we have come up with gives us an increase of its weight in comparison with the weight which is necessary to provide the required eccentric moment. So decreasing the moment of the rotary parts makes it easy to operate the motors.

Sizing the Bearings

The rotor shafts are mounted to spherical, double-row roller bearings No 3614 which have a coefficient of workability C = 330,000. The rotor weight Gb = 25 kgf. The eccentric weight is Gg = 28 kgf.

For the calculation of dynamic loads consider that the accelerations during impact are equal to 150 times the free weight.

As the shaft is symmetrical, each bearing is subjected to half the dynamic load

The shaft rotates at n = 950 RPM. Consider a factor of safety Kd = 1.5 and a dynamic load coefficient Kk = 1. The durability of the bearing “h” is determined as

Therefore, for 950 RPM, h = 160 hours.

 

Soviet S-834 Impact-Vibration Hammer: Calculations, Part I

The introduction to this series is here.

Moscow, 1963

Head of the Vibrating Machine Department L. Petrunkin
Head of Vibration Machine Construction: I. Friedman
Compiler: V. Morgailo and Krakinovskii

Specification

The impact-vibration hammer is intended for driving heavy sheet piles up to 30 cm in diameter as well as concrete piles 25 cm square up to a depth of 6 m for bridge supports and foundations.

Parameter

Value

Power N, kW

9

Blows per Minute Z

475

Revolutions per Minute

950

Ram mass

,
kg

650

Force F, kgf

5000

Determination of Velocity and Energy per Blow

Impact velocity is determined:

where = fraction of natural frequency (without limiter) to force
frequency

i = fraction of the number of revolutions to the number of impacts
R’= coefficient of velocity recovering (assume R’=0.12)

In our case

therefore

rad/sec

kgf-sec²/m

Energy of blow is determined as

Power necessary to make impacts is

Impact-Vibration Hammer Springs

So that the impact-vibration hammer operates in the optimal mode while the gap is equal to zero, the spring suspension stiffness should meet the equation

where = stiffening coefficient = 1.1 to 1.3, assume 1.2

Stiffness Distribution and Maximum Deformations
of Upper and Lower Springs

The upper springs are necessary to provide positive gaps, so their stiffness should be minimal to provide undisplaced operation the springs in the whole range of gap adjustment. Therefore

where Cb = stiffness of the upper springs
A = number of vibrations of the ram

a = maximum positive gap when the hammer is able to operate without danger of transferring into the impactless mode. When there is no limiter it is equal to the amplitude of vibrations

Assume a = 0.8.

where = coefficient which depends upon i and R’. Hammer coefficient of
velocity recovery may be increased up to R’ = 0.2. In this case = 7.1.

For calculation purposes let us assume A = 5.5. Now substitute the values into the formula

The bottom spring stiffness is then equal to

Now let us determine the maximum deformations. For upper and lower springs,

where b = negative gap. It is considered equal to “a” (maximum positive gap)

Assume .

Because of design considerations use four (4) upper and four (4) lower springs. The stiffness of one upper spring is

and the stiffness of one lower spring is

The material for the spring is “60 Sg” steel. The permissible tension in this steel is kgf/cm².

Upper Springs

Tension per kgf of load is

According to the table of S.I. Lukowsky choose the spring as follows:

The stiffness of one turn and the number of working turns is

Assume turns. For this spring,. The actual tensions in the spring are as follows:

(Units should be kgf/sq.cm.)

and the total number of turns is

The full free height of the spring is

The distance between the support surfaces while the gap is equal to zero is

Lower Springs

According to the table the closest value A = 4.24 corresponds to the spring with dimensions

The stiffness of one turn is equal to . The number of working turns is

Assume 10 turns.

The total number of turns is

The spring height in free position equals to

 

Soviet S-834 Impact-Vibration Hammer: Overview

With this we begin a series of posts on the S-834 impact-vibration hammer, which the VNIIstroidormash institute in Moscow designed and produced in the early 1960’s.  With the revived interest in Soviet and Russian technology, it’s a detailed look at how Soviet equipment designers came up with an equipment configuration.  But it’s also a close-up view of how heavy machinery in general and pile driving equipment in particular is designed.

The impact-vibration hammer was a long-time interest for Soviet construction machinery institutes from 1954 to 1970.  An overview of the history of this type of equipment in the Soviet Union is here.  Since vibratory pile driving equipment was first developed in the Soviet Union, it’s also interesting to look at the entire subject; that overview is here.

The series is in three parts:

General View of the S-834 Hammer

The specifications for the S-834 are here.  What follows is an overview of the hammer itself and its general construction.  We apologise for the poor quality of the scans.

A general view of the machine. The impacting ram (1) is driven by eccentric weights and a motor within, which both lift it and force it down to impact. The hammer frame (2) receives the pile from below through a centre hole, which makes it possible for (1) to impact the pile. The motion of (1) is governed by the upper and lower springs (3). The compression on those springs is adjusted by (4), (5) and (6).
A cutaway view of the impacting ram. Basically the centre shaft (3) is driven by the electric motor (2), which in turn rotates the eccentrics (9). The force is transmitted from the eccentrics to the body (1) via the bearings (4) and the bearing housings (5). Electrical power is fed to the motor at the electrical connections (12). Once the entire assembly reached the impact point, impact force is transmitted to the pile at the ram point (10).
The ram point’s force is transmitted through the anvil (5) to a wood cushion (1), which in turn transmits the force to the pile, whose head is inserted through the tapered receptacle (2). The size of the receptacle can be adjusted with (3). The leader guides (6) are used for the leaders, which are (in typical Soviet and European fashion) behind the hammer.
Another variation of the anvil assembly.
This shows how the pile is drawn up into the leaders. The pile is attached to the bottom of the frame using a sling. This was common practice in the Soviet Union and is also done elsewhere. The alternative is to use a separate pile line. If the equipment is configured properly, this can work well.

Design Calculations for the S-834

In the posts that follow, the design calculations for the S-834 will be presented.  In looking at the work of Soviet designers, it was tempting to revise the calculations.  For one thing, although the metric system was introduced with the Russian Revolution, their implementation of the system is not really the “SI” system taught today, especially with the use of the kilogram-force.  (That’s also true with many other Continental countries such as Germany and France.)  For another, Russian technical prose can be very cryptic.

In the end, it was decided to reproduce the calculations pretty much “as they are,” with a minimum of revision.  We apologise for the inconsistent sizing of the equations.  Most of the transcription of this information was done in the 1990’s in Microsoft Word, and its conversion to HTML (for this format) in LibreOffice made the equations graphics (a good thing) but inconsistently sized the images (a bad thing.)  This is one reason why we’ve migrated to LaTex for our newer technical productions online.

As with much of the Soviet material on vibration and impact-vibration pile driving, I am indebted to VNIIstroidormash’s L.V. Erofeev for the material itself and V.A. Nifontov for its translation.

The Valve Loss Study

All fluid flow in Vulcan hammers is regulated and directed by a valve.  For most Vulcan hammers (the California series being a notable exception, the #5 is another) the valve is a Corliss type valve modified from those used in steam engines.  Simple and reliable, it, like any other valve, is subject to losses as the air or steam passes through it.  These are reflected in the mechanical efficiency of the hammer.

The losses due to air or steam flowing through the valve are generally not the most significant source of energy losses in a pile hammer.  In the late 1970’s and early 1980’s, with the increase in sheer size of the hammers, these losses became of more concern.  It was necessary to at least attempt to quantify these losses instead of using a “standard” back pressure value.

In May 1979 Vulcan contacted the Georgia Institute of Technology in Atlanta about using a Vulcan #1 series valve (like used in the #1, 06, etc.) in a test to determine the losses of air flowing through these valves.  At this point a major problem was encountered: the air flow required to properly test the valve was too large for Georgia Tech’s equipment.  Reaching out to Lockheed didn’t help either; they couldn’t do it.  At this point Vulcan came up with an alternative: use the DGH-100 valve, which was a Corliss valve albeit much smaller, for the test.  Making things easier was the fact that the DGH-100 used a small aluminium valve chest, which made the valve mounting simpler.

This proved feasible and Vulcan received a proposal from Brady R. Daniel at Georgia Tech for these tests.  The valve was tested in two “configurations”:

Configuration A Valve Orientation
Configuration “A” is the valve orientation which allows the inlet fluid to pass around the “back side” of the valve and into the cylinder. For single-acting hammers, this is the lower side of the piston, and takes place during the upstroke. For differential-acting hammers, this is the upper side of the piston, and takes place during the top part of the upstroke and during the downstroke.
Configuration B Valve Position
Configuration “B” is the valve orientation which allows the inlet fluid to pass through the “slot” in the valve and out of the cylinder into the atmosphere. For single-acting hammers, this is the lower side of the piston, and takes place during the top of the upstroke and during the downstroke. For differential-acting hammers, this is the upper side of the piston, and takes place during the early part of the upstroke.
Configuration A Test Setup
The test setup for Configuration A.
Configuration B Test Setup
The test setup for Configuration B.
General Arrangement of Valve and Test Apparatus
Test Arrangement for Configuration A
Test Arrangement for Configuration B

The tests were run and the report was presented in October 1980.  The immediate results were as follows:

  1. The report showed that the valve could be modelled essentially as a sharp-edge orifice.  In the context of incompressible fluids, this is explained here.
  2. A numerical method was developed to analyse the hammer cycle, as opposed to the closed-form solutions that had been used since the beginning of Vulcan pile hammers.  This led to some design changes, and was also adapted for the Single-Compound hammer design.

The report also contained some suggestions for “streamlining” the design of the valve.  These were not adopted, and the reason should be noted.

With the Corliss type valve, the Valve Port 1 is continuously pressurised, and this in turn forces the valve against the valve chest (or liner in the case of most newer Vulcan hammers.)  With proper lubricant this seals the valve and further sealing (rings, seals, etc.)  are unnecessary.  This is a major reason why Vulcan hammers are as reliable as they are under the dire circumstances many operate.  But that comes with a price.  As with any design, there are trade-offs, and in this case the simplicity of the valve is traded off for efficiency.  The simplest way to deal with this is to properly size the valve, and this was the main reason for the Valve Loss Study.

The Valve Loss Study is an interesting example of design analysis (others are here) which even an old product line like Vulcan’s can benefit from.

Back in the Saddle at the Deep Foundations Institute

dfi

Vulcan Iron Works was involved in its industry in a number of ways other than simply selling and renting its product.  One of these was its years in the Deep Foundations Institute.  Although Vulcan was not a charter member of the organisation, it joined very shortly after its beginning and was active during the 1980’s and early 1990’s, until about a year before the merger with Cari Capital.  This webmaster was the Program Chairman for the 1992 DFI Annual Meeting in New Orleans.

So it is with pleasure that I have joined the DFI once again, continuing another tradition of the “Old Vulcan.”  My thanks to Theresa Engler, DFI’s Executive Director, who helped make this a reality.