US3380541A

US3380541A - Sonic method and apparatus for installing complex structures

Info

Publication number: US3380541A
Application number: US492553A
Authority: US
Inventors: Jr Albert G Bodine
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-10-04
Filing date: 1965-10-04
Publication date: 1968-04-30
Anticipated expiration: 1985-04-30
Also published as: GB1163268A; DE1634270A1; FR1500427A

Description

April 30, 1968 A. G. BODINE. JR 3 5 SONIC METHOD AND APPARATUS FOR INSTALLING COMPLEX STRUCTURES Filed Oct. 4, 1965 4 Sheets-Sheet 1 .j Q m/l/EA/roe ALBERT e. BQD\NE,JR. M [3 5* Y A77'ONE'Y April 30, 1968 A. G. BODINE, JR 3,389,541

SONIC METHOD AND APPARATUS FOR INSTALLING COMPLEX STRUCTURES Filed Oct. 4, 1965 4 Sheets-Sheet 2 55 INVENTDB ALBERT G. BODNE,JR.

April 30, 1968 A. G. BODINE, JR

SONIC METHOD AND APPARATUS FOR INSTALLING COMPLEX STRUCTURES 4 Sheets-Sheet 5 Filed Oct. 4, 1965 I I i,w-i a HAF //Vl/E/\/7'O2 ALBERT G. BODlNEJR. BY f April 30, 1968 A. G. BODINE. JR 3,

SONIC METHOD AND APPARATUS FOR INSTALLING COMPLEX STRUCTURES Filed Oct. 4, 1965 4 Sheets-Sheet 4 FIG. /2

INVENTOR. ALBERT G. BOD\NE.,J'R. 62\

BM BY 1?.2 W

A7TOE/VE Y United States Patent 3,380,541 SONIC METHOD AND APPARATUS FOR INSTALLING COMPLEX STRUCTURES Albert G. Bodine, Jr., 7877 Woodley Ave., Van Nuys, Calif. 91406 Filed Oct. 4, 1965, Ser. No. 492,553 18 Claims. (Cl. 175-19) ABSTRACT OF THE DISCLOSURE A method and apparatus is disclosed herein for driving prefabricated structures having a plurality of longitudinal support members or piles into the earth. Independently acting acoustical driving apparatus coupled t each support member generates elastic waves in the members causing them to be driven downwardly. For asymmetrical structures, a fixed bias Or balancing mass is afiixed to permit the generated standing wave to be isolated from the lateral superstructure. Coupling means are provided between the longitudinal supports and the lateral superstructure for eliminating parasitic vibrations and flexure therein.

Specification This invention relates to a method and apparatus for driving prefabricated structures into the earth such as are used for supporting buildings, bridges, or other structural elements, and which structures may be complex, or unsymmetrical and/or have multiple supporting appendages.

There has been disclosed in my Patent No. 2,975,846 entitled, Acoustic Method and Apparatus for Driving Piles, a sonic method and apparatus for driving piles into either land, underwater surfaces, or other media, employing sonic fluidizing effects. These piles are typically described as being constructed of steel, wood, concrete and they may be of various cross-sectional configurations, such as H-sections, corrugated, tubular, or of other columnar shapes. In any event, all of these structures are described in the aforementioned patent as being driven into the earth by means of an elastic wave generator acting on the pile to establish a standing wave vibration in the pile whereby it may be driven downwardly. In the examples given in the aforementioned patent, the pile is given a vibration in the sonic range which places the pile in resonance. When the pile is placed in resonance such as to have a standing wave placed therein, the pile vibrates as a free-free bar with a velocity antinode at each end, and usually a node at the midpoint. The pile in undergoing such standing wave action cyclically undergoes elastic elongations and contractions. This causes the lower end of the pile to activate the earth whereupon it will be more easily driven downwardly.

With the advent of modern and complex structures such as is used in building construction, bridges, elevated piers for mass transit systems and other complex structures, the use of the conventional pile driving equipment is usually precluded due to the complex physical nature of the structures. In addition, it is often necessary to install a structure having a plurality of downwardly extending longitudinal members or appendages. These structures when driven into the ground, and when placed into final position, frequently have a rather complex laterally extending superstructure supported thereon.

In the past, when such structures having multiple appendages for supporting a superstructure, were mounted in the ground, it was necessary that each pile element be individually installed by means of a pile driver and after the entire under structure was placed in final position, then the superstructure would either be lowered onto the under structure, which necessitated, rather large, cumbersome and expensive equipment, or the superstructure was constructed in situ.

To obviate the many deficiencies of the prior art, one aspect of this invention is directed to a method and apparatus by means of which complex building structures may be prefabricated as a unit and installed in a single operation by simultaneously driving all of the supporting members into the earth. These complex structures may take the form of a plurality of longitudinally extending piles which are a part of a total system or a bent such as, for example, a bridge. Typically, these piles have mounted on the top thereof a superstructure which may take any number of configurations. To drive the entire supporting system into the ground, each of the longitudinal members or piles may, for example, have mounted thereon an independently operated acoustical driving apparatus.

Another important feature of this invention is a method and apparatus for driving longitudinal members or piles into the ground where the piles have attached thereto an asymmetrical structure. The structure is driven by acoustical driving apparatus and a fixed bias or balancing mass is applied to the structure to permit the desired standing wave to be imparted to the longitudinal member of members.

According to another embodiment of this invention, wherein a plurality of longitudinal members are to be driven into the earth and upon which a superstructure must be placed or driven, the superstructure is decoupled acoustically from the longitudinal member and, the longitudinal members are driven by sonic pile driving apparatus. Acordingly to this embodiment of the invention, each of the longitudinal members has mounted thereon an acoustical driving apparatus and the longitudinal members support a superstructure which is decoupled acoustically from each of the longitudinal members.

Another embodiment of this invention includes a method and apparatus for driving a plurality of longitudinal members upon which is attached a superstructure wherein means are provided at the velocity antinode 0f the superstructure which comprises a laterally extending mass means to provide damping so that the superstructure is dead as to flexural modes in the manner of a leaf spring.

In another embodiment of this invention, flexural modes of vibration are encountered when a plurality of longitudinal members are driven into the earth with laterally extending superstructure imposed thereon as prevented by providing internal damping of the superstructure. This can be accomplished by providing damping inlays or by changing the sonic characteristics of the material comprising the superstructure.

In another embodiment of this invention, wherein a longitudinal member with an offset laterally extending mass may be subject to fiexural modes of vibration which cause the laterally extending mass to bend or flap as the longitudinal member is placed in resonance is prevented by the provision of a balancing mass to compensate for the laterally extending superstructure.

In another embodiment of this invention, a member is driven into the earth by means of a pile driving apparatus and in which the direction of penetration of the member is provided for by utilizing a biasing means.

Still another embodiment of the invention, in which multi-legged pile structures are driven into the ground as a unit, involves a system concept as regards the sonic resonant circuit. Whereas conventional straight columnar piles represent a fairly simple linear dimensional element, having elementary resonance patterns, complex pile assemblies of the type to which the present invention applies may have many degrees of freedom in terms of acoustic resonance patterns. Therefore, particular care must be exercised in order to achieve an effective driving mode or pattern. If resonance of an assembly having several appendages is involved, wherein the appendages resonate somewhat in the manner of individual piles, then it is important that the resonant mode be one wherein the mutual attachment points are at regions of compatible acoustic impedance for the connected appendages.

By choosing a longitudinal mode having minimum coupling to lateral modes of lateral structure portions, unwanted vibration in the transverse or connecting portions of the structure will be suppressed. That is, in those complex structures having laterally extended members or portions of the basic structure, these lateral portions tend to develop flapping modes. These flapping modes can reach destructively high amplitudes if such flapping modes happen to occur at a frequency which is nearly the same as the resonant frequency of the chosen longitudinal mode for the main pile member which is being driven into the ground.

In accordance with the present invention the longitudinal appendage, that is, the main pile member, can usu' ally be driven by resonating it at a longitudinal overtone pattern. Moreover, these overtones occur as a series of higher modes. By selecting a mode for the longitudinal portion of the system which has a resonant frequency substantially differing from the resonant frequency of the undesired lateral mode, in the laterally extending portions of the complex structure, the amount of energy imparted to the lateral portions will be greatly reduced. This will obviate damage to the transverse or laterally extending portions of the structure.

It is therefore an object of this invention to provide a method and apparatus for applying a longitudinal mode of vibration to a complex structure which does not acoustically couple to undesired lateral modes.

It is also an object of this invention to provide a method and apparatus for driving into the earth complex structures characterized by a plurality of pile members by providing for each pile member an independently operated acoustical driving apparatus.

It is another object of this invention to provide a method and apparatus for driving asymmetrical building structures into the earth by providing a fixed bias such as a balancing mass to permit the creation of a desired standing wave in the struucture.

It is another object of this invention to provide a method and apparatus for acoustically decoupling the superstructure of a complex building structure from longitudin-al members which are driven into the earth or the like so as to eliminate spurious or parasitic vibrations in the superstructure which drains energy from the driving energy of the pile driving apparatus.

It is another object of the invention in which the fiexural mode of vibration in a superstructure upon a series of longitudinal members are eifectively dampened by means of internal dampening means.

It is another object of this invention to eliminate the fiexural mode of vibration, which is spurious or parasitic in a laterally extending superstructure upon a plurality of longitudinal members, by means of outside dampening.

It is still another object of this invention to compensate for a fiexural mode of vibration in an unbalanced longitudinal member having a laterally extending mass by providing a balancing mass to compensate for the flexural mode.

It is still another object of this invention to provide a method and structure for driving a member into the earth by providing a bias so as to change or predetermine the direction of penetration into the earth or the like.

Other objects and advantages of this invention will become apparent as this description proceeds taken in conjunction with the drawings, in which:

Summary of the invention Applicant has succeeded in achieving the aforemen tioned objects and in overcoming the disadvantages of the prior art by providing a method and apparatus for driving prefabricated structures having a plurality of support members into the earth. In the preferred embodi' ments, independently acting sonic generators are coupled to each support member and generate a standing wave vibration within the member thus permitting it to be driven downwardly. The vibration places the member in res0- nance with an antinode at each of its ends and causes cyclical elastic elongation and contradiction of the member. When the structure is asymmetrical, a bias is pro vided generally in the form of a balancing mass to reduce and/or eliminate any spurious or parasitic vibrations within the superstructure. Acoustical decoupling ap paratus are provided intermediate the sonic generator and the lateral superstructure so as to isolate the lateral superstructure from vibration and flexure.

FIGURE 1 is a side view of a plurality of longitudinal members and a superstructure thereon with a sonic driving apparatus for each longitudinal member;

FIGURE 2 is a side view of a plurality of longitudinal members having a superstructure and an asymmetrical mass with a sonic driving apparatus and a biasing mass for compensating the asymmetrical mass;

FIGURE 3 is a side view of a complex structure similar to FIGURE 2 but with an acoustical driving apparatus for each longitudinal member;

FIGURE 4 is a side view of a plurality of longitudinal members and a superstructure imposed thereon and which utilizes sonic driving apparatus and a decoupling mechanism;

FIGURE 5 is an electrical analogy to the acoustic system as shown in FIGURE 4;

FIGURE 6 is a view of a plurality of longitudinal members and a superstructure imposed thereon in which outside damping means are provided to increase damping of the laterally extending superstructure;

FIGURE 7 is a view of a structure including a plurality of longitudinal driven members and a laterally extending superstructure in which internal means are provided to increase damping in the laterally extending superstructure so as to reduce fiexural modes therein when the longitudinal members are in resonance. A closeup of the decoupling means of FIGURE 4 is included for clarity;

FIGURE 8 is an electrical analogy to the acoustic structure of both FIGURE 6 and FIGURE 7;

FIGURE 9 is a view of a longitudinal member on which a laterally extending member extends unsymmetrically and on which a balancing mass is utilized to compensate for the fiexural mode and in which biasing means are provided for changing the direction of penetration of the device;

FIGURE 10 is a front elevational view of a hornshaped structural member, showing the manner in which a sonic oscillator is attached thereto to accomplish the method of the invention;

FIGURE 11 is a cross sectional view taken along line 11-11 of FIGURE 10;

FIGURE 12 is a fragmentary view of an end portion of a structure of the type shown in FIGURE 6, and which illustrates outside damping means clamped to the superstructure;

FIGURE 13 is a cross sectional view taken along line 13-13 of FIGURE 12, showing the manner of installation of the outside damping means.

Normally, when complex building structures such as bridges, tramways, overpasses and other structures are constructed, the usual practice is to drive a plurality of piles and after they have been driven to mount thereon the superstructure. This necessitates either lifting the superstructure and placing it on the driven piles or constructing the superstructure in situ. Shown in FIGURE 1 is one way in which a complex building structure characterized by a superstructure and a plurality of pile members can be driven into the earth as a unit by the practice of this invention.

The structure to be driven into the earth 11 is shown generally at 1 and comprises a superstructure 3 and

longitudinal pile members

5, 7 and 9. Mounted on

pile members

5, 7 and 9 are

sonic wave generators

13, and 17. These sonic wave generators are clamped onto the longitudinal pile members in a manner such as disclosed in my U.S. Patent No. 2,972,380. The use of a separate sonic wave generator for each pile member is an important feature of this form of this invention since the resonant frequency characteristics of each pile member differs from that of the other pile members, particularly when the depth of penetration of each pile differs from the other piles. Each of the oscillators locks in at the resonant frequency of the pile on which it is mounted as more particularly described in US. patent application Ser. No. 496,468.

In FIGURE 2, a complex structure 21 is illustrated and includes a superstructure 23 and pile members 25, 27 and 29. Shown generally at 31 is a typical structural mass which renders complex structure 21 asymmetrical. This can create problems such as providing an undesirable reactance in a given direction as well as inducing undesirable parasitic lateral vibrations, and varying the frequency response characteristics of the structure. To compensate for this, a balancing mass or inductance 33 is provided which in an acoustical sense makes the total structure act as a T. Accordingly, the balancing of structure 21 permits oscillator 35 to impart to pile members 25, 27 and 29 standing waves without harmful effects contributed by an asymmetrical structure.

In FIGURE 3, a modification of the structure of FIG- URE 2 is shown. The complex structure 41 has a superstructure 43,

longitudinal members

45, 47, 49, 51 and 53 and a structural mass 55 which renders structure 41 asymmetrical. To render structure 41 symmetrical, mass 57 is attached to structure 41. In a manner similar to FIGURE 1,

individual oscillators

59, 61, 63, and 67 are provided.

By the use of a sonic generator for each pile member, the total complex system can be driven as one unit rather than individually. The individual units have the advantage not only of being able to transmit the driving force directly to the pile but also of being able to lock in at the pile frequency independently of the other pile members. In conjunction with this, the use of the balancing or fixed bias allows the formation of the desired standing waves in the longitudinal members.

Under certain conditions, the superstructure or laterally extending portions create problems in the driving of the structure due to vibrations in the lateral portions. FIG- URE 4 illustrates one way to obviate these ditliculties.

Acoustically speaking, these laterally extending portions such as shown by 2 in FIGURE 4 are ordinarily acoustically coupled to each of the

columns

4, 6 and 8. The superstructure 2 tends to be acoustically driven to a substantial degree by sonic action in each of the

main columns

4, 6 and 8. When such a structure is to be driven, the high frequency which is generated in the

longitudinal members

4, 6 and 8 tend to elicit an active acoustic response in the laterally extending portions of superstructure 2. This occurs even though the laterally extending portions may be of considerable less longitudinal dimension than th main column. The reason for this is that the laterally extending portions, because of their physical orientation relative to the main column, are subjected to a flexural mode of elastic vibration even though the

longitudinal members

4, 6 and 8 are longitudinally excited. What occurs is that the laterally extending portions of the superstructure 2 tend to bend when the main column elongates and contracts much as a lateral appendage in the manner of a birds wing. This phenomena is particularly undesirable if the flexural mode frequency response of the lateral portion is anywhere near the driving operating frequency of the longitudinal mode of each of the

main columns

4, 6 and 8. It is to obviate this flexural mode to which this embodiment is directed as represented in FIGURE 4. For example, when the laterally extending portion of superstructure 2 is energized by the acoustic driving apparatus, much energy is Wasted. In addition, the danger exists that the superstructure and/or one of the longitudinal columns may be damaged or destroyed.

Shown schematically at 10, 12 and 14 are sonic pile driver apparatus which may be constructed in the manner disclosed in U.S. Patent No. 2,972,380. These sonic pile driving apparatus are clamped such as taught by US. Patent No. 2,972,380 onto the

longitudinal members

4, 6 and 8, respectively, so as to impart a standing wave in each of the longitudinal members on which the sonic pile driving apparatus is attached.

Without the decoupling means, according to this embodiment of the invention, when the sonic pile driving apparatus 10, 12 and 14 are actuated, a longitudinal standing wave is created in each of the

longitudinal members

4, 6 and 8 such that a velocity antinode is created at the bottom of each pile whereby, as described in US. Patent No. 2,960,314 each of the longitudinal members are driven into the earth. However, when thesuperstructure 2 is attached to the longitudinal members during driving, much of the energy which normally would be transferred to the

longitudinal members

4, 6 and 8 is wasted by dissipation in vibrating superstructure 2. To obviate this condition, a decoupling apparatus is provided above each of the oscillators 10, 12 and 14 and more particularly shown as 16, 18 and 20. This decoupling may take any form but in its simplest embodiment merely comprises a sleeve 22 (see FIGURE 7) which may be attached to each of the

columns

4, 6 and 8 as by welding, bolts or the like. The superstructure is then merely loaded on each of the

longitudinal members

4, 6 and 8 such that gravity alone creates support holding the superstructure 2 on the longitudinal members. The net result of this construction is that a joint is provided which is adequate for large compressional loading but does not transmit the total cyclic sonic action or more particularly the negative phase of each cycle. This results (utilizing an electrical analogy) in an acoustic rectifier or decoupler and therefore a poor transmitter of sonic energy.

The electrical analogy of the structure shown in FIG- URE 4 is illustrated in FIGURE 5.

It is convenient in explaining the acoustic nature of the sonic pile driving apparatus of this invention to compare it with an electrical system. This comparison is a natural one as this type of analogy is well known to those versed in the art and is described for example in Dynamical Analogies by Harry F. Olson, published in 1943 by D. Van Nostrand Co., N.Y., and in Chapter 2 of Sonics by Hueter & Bolt, published in 1955 by John Wiley & Son.

In any mechanical system in which an acoustical vibration is present, there is friction, elastic stiffness reactance (compliance) and mass which correspond to the electrical components of resistance, capacitance and inductance. The analogy is summarized as follows:

Each of the

longitudinal members

4, 6 and 8 may be compared to the electrical system as shown in FIGURE 5 within dashed

lines

4a, 6a and 8a. In each of these longitudinal elements there are the various elastic stiffnes reactance (or compliance) of the pile which corresponds to capacitance 24. For purposes of clarity, the characteristics of circuits 6a and 8a are similar to circuit 4a. The friction between the oscillator, which is shown as a sine wave generator 26, and pile 4 is analogized as resistance 28. Internal dampening of the pile is compared to resistance 30 while the interface friction between the pile and the earth is shown at 32. The bottom reaction of the pile and the earth is shown at 34 while the lumped inductance 36 corresponds to the velocity antinodes (or mass) of the mechanical system. The corresponding electrical analogies shown generally as 6a and 8a correspond to longitudinal elements 6 and 8 in the same manner as 4 and 4a.

The superstructure resistance, capacitance and inductance analogy which corresponds to the similar elements for impedance of

longitudinal members

4, 6 and 8 is illustrated generally within the dotted lines as 40. The damping, hysteresis and other frictional losses is shown as a lumped resistor 40a, the stiffness as capacitance 40b and the velocity as inductance 400.

Thus it can be seen that there is impedance in the superstructure 2 which can drain energy from each of the oscillators which is accordingly dissipated and not used to drive the piles into the earth. Therefore, it is incumbent to reduce this drain of energy. In this particular case, the drain of energy is substantially prevented by providing a rectifier or decoupler in the mechanical system which corresponds to a rectifier in the electrical system. This is accomplished, as shown in FIGURE 4, by providing means to prevent the tension phase of the sonic waves from traveling from the longitudinal members to the lateral members to prevent flexural modes from being created in the laterally extending superstructure. By providing a break between the

longitudinal members

4, 6 and 8 and the superstructure, a decoupling or rectifying action occurs. This is analogous to the electrical system in which rectifiers shown generally as 42, 44 and 46 between the sine Wave generators and impedance 49 are provided.

Thus, it can be seen that by the simple provision of decoupling means between the laterally extending superstructure and the longitudinal members to be driven into the ground, harmful flexural modes and vibrations in the superstructure can be substantially eliminated. The sonic energy from the driving apparatus can therefore be transmitted to the longitudinal members without dissipation through the laterally extending superstructure.

Shown in FIGURE 6 is another means and method by which the flexural modes of vibration transmitted to a superstructure attached and integral with a plurality of longitudinal members is illustrated. S0, 52, 54 and 56 are illustrative of longitudinal pile members which are to be driven into the earth and upon which is attached or integral therewith a superstructure 58. To prevent the lateral or fiexural modes of vibration from becoming harmful, the embodiment of FIGURE 6 is directed. Mounted on superstructure 58 is an oscillator indicated generally at 60. Oscillator 60 includes two oscillator prime mover or

engine elements

62 and 64 mounted on a common base 66 which are attached to vibrating members 68 and 70 by means of shafts '72 and 74, respectively. Said vibrating members, or oscillators, can be of the type shown in my Patent No. 2,960,314. With this arrangement, the rotating shafts cause the rotating weights in oscillators 68 and 70 to transmit sonic vibrations to the total structure in a longitudinal direction (vertical).

When oscillator

prime movers

62 and 64 are activated, vibrating elements 68 and 70 transmit longitudinal vibrations to the pile members 50, S2, 54 and 56. However, as mentioned with reference to FIGURE 4, lateral or parasitic vibrations are transmitted to laterally extending superstructure 58 which is dissipated therein and therefore dissipating energy which ideally should be directed to the longitudinal elements. Base 66 is clamped to laterally extending superstructure 58 by clamps 66a and 66b while clamps 68a and 70a hold supporting structures 68b and 70b. If desired, bar 71 and clamp 73 can be utilized.

Assuming that when the longitudinal members are driven into the earth lateral vibrations occur in laterally extending portion 58, a plurality of velocity antinodes and nodes will occur in the latter. These are schematically represented above superstructure 58 and include nodes 80, velocity antinodes 82 and

nodes

84, 86, 88 and 90. Likewise, velocity antinodes will be represented at 82, 92, 94 and 96. It is to suppress these velocity antinodes to which this embodiment of the invention is directed. This is accomplished by placing, for example at the velocity antinodes, a container 98 filled with lead shot, sand, junk iron, or the like. This has the effect of providing a dissipation within the container by the particles rubbing against each other as well as providing a mass to suppress the velocity antinode. In other words, these containers filled with loose material act as an impactabsorption type of acoustic damping.

To envision this in an electrical circuit analogy, referonce is made to FIGURE 8. Thus, each of the

longitudinal pile elements

50, 52 and 54 are represented in the electrical circuit as 100, 102 and 104. The circuit for member 56 is similar and is omitted here for clarity. Each of these circuits contain the inductance, capacitance and resistance as aforementioned with reference to FIG- URE 5. The sonic driving apparatus 60 is shown as a sine wave generator 108 and the inductance of the laterally extending superstructure 58 is illustrated at 110. To change the frequency response of the laterally extending portion, at least one container of sand, shot, junk iron, etc. 98, may be provided as represented in dotted lines in the electrical circuit as two circuits 112 and 114. The capacitance 116 in electrical circuit 11 can be com pared to the compliance of the lead shot, sand, junk iron or the like, while the dissipation within the container caused by the constituent particles therein rubbing and randomly impacting against each other is the resistance 118. While two electrical circuits are illustrated in matching the impedance, it is understood that a plurality of these boxes or containers can be utilized and while only one is illustrated in FIGURE 6 and two of them in FIGURE 8, any number of these can be provided to dampen the velocity antinodes.

In FIGURE 7, another way of tuning out the impedance of the superstructure is shown. This can be accomplished in a variety of ways and if desired instead of providing a loose mass or container material at the velocity antinodes, dampening can be accomplished by using a material or inlay in the superstructure as illustrated at 120. This can be a reinforcing material which not only aids in dampening the spurious or parasitic lateral vibrations in the superstructure but acts as a reinforcing member in static loading as well. While a plurality of these are shown at 120, 122, 124 and 126, it is to be understood that any combination of one or more of these inlays can be provided to suppress lateral vibrations. Another manner of providing internal damping is to provide a low Q aggregate 127 in the member such as, for example, in concrete structures. This has the effect of reducing the response level of the lateral portion. This is accomplished by making the lateral portions of the structural material acoustically dead which, when expressed in other words, means that it has high internal damping.

It may be noted that the factor Q" is described as the ratio of energy stored in the system to the energy dissipated per cycle. In other words, with a high Q factor, the sonic system can store a high level sonic energy to which a constant input and output of energy is respectively added and subtracted. Circuit-wise this Q factor is numerically the ratio of inductive reactance to resistance. The high Q system is dynamically active giving considerable cyclic motion where such motion is needed. Since excessive motion is undesirable in the lateral portions of the structure, for ordinary type of construction, and motion, ideally speaking, should be transmitted primarily to the longitudinal members, it is sometimes desirable that the Q factor be controlled for the laterally extending superstructure. Accordingly, by providing internal damping through the use of inlays, or by providing a difierent aggregate in the material comprising the laterally extending portion, this Q factor can be substantially reduced, thus not robbing the total system of the energy necessary to drive the longitudinal members into the earth.

With reference to FIGURES l2 and 13, there is shown still another embodiment of a lateral wave damper for suppression spurious lateral modes of vibration. This lateral wave damper comprises rail member 147 which extends along the upper surface of the complex structure 58. This complex structure 58 is the same structure as shown in FIGURE 6, and the portion shown in FIGURES 12 and 13 may, for example, be the left end portion of the structure as viewed in FIGURE 6.

Clamps

148 and 149 are secured to, and depend from, rail member 147 on either side of structure 58. The lower ends of

clamps

149 and 148 are provided with apertures through which extends bolt 151.

Tapered washers

152 and 153 are carried on bolt 151 and urge shim 154 upwardly against the lower abutting surface of structure 58. Nut 159 is threadily attached to bolt 151 and when tightened will force tapered

washers

152 and 153 towards each other.

The above-described lateral wave damper resembles a splint which is clamped to the lateral portion of complex structure 158 and applies a damping function, much like the leaf in a leaf spring.

Referring to FIGURE 9, another means of driving a longitudinal member having a superstructure which does not lend itself to the ordinary apparatus heretofore used is shown. The longitudinal member to be driven into the ground is illustrated at 130. This longitudinal member has a laterally extending structural extension 132 which renders the system as a whole, unbalanced. Shown schematically at 134 is an oscillator or vibration causing member which transmits sonic vibrations to longitudinal member 130 in the manner heretofore described. However, in this case as in the previously discussed examples, laterally extending vibrations or flexural nodes can occur in the laterally extending portion 132, and also be carried into member 130, thus robbing the total system of energy. To counteract this, this embodiment includes a balancing mass 136 which is temporarily attached to the upper end of the structure 130 so as to counteract for the unsymmetrical portion 132. Also shown in this embodiment are biasing

means

140 and 142 so that if the structure is desired to be driven into the earth at an angle, or to a closely determined location, either one of the biasing

forces

140 and 142 may be activated by

winches

144 and 146 so as to direct the longitudinal member 130 into the ground at any desired later position or angle including horizontal.

Thus in operation, when oscillator 134 is activated so as to transmit sonic vibration to the longitudinal member 130, the member will be driven into the ground. When it is desired to tilt the longitudinal member 130 in any desired direction, bias is applied by either 140 or 142 through

winches

144 and 146, depending upon the desired direction of penetration, to cause the longitudinal member 130 to enter at a desired angle during the sonic vibration while the earth is fluidized.

Looking now at FIGURE 10, there is shown a type of complex structure 161 in which the longitudinal appendage has a horn-shaped configuration. That is, the downwardly extending portion of the structure has a circular cross-section something like a golf tee. With which such a hornshaped structural member it is possible to generate a longitudinal wave system, wherein the entire structure is subjected only to a longitudinal wave pattern. Because of its greater mass, the upper portion of this horn-shaped structure tends to vibrate at a reduced aptitude. This upper portion would present a relatively high impedance to the driving oscillator. Therefore, it is usually desirable with structures of this type to secure the sonic oscillator 162 to the more slender portion of the structure so that the oscillator 162 will be coupled at a lower impedance region, where the amplitude can be of substantial magnitude. That is, by coupling the oscillator to a low impedance region, substantial acoustical energy will be obtained from the oscillator 162. The manner in which oscillator 162 is clamped to structure 161 is also shown in FIGURE 13. It is important to note, in connection with this embodiment of the invention, that due to the gradual taper of the structural member 161, all of its vibration will be longitudinal, thus greatly minimizing the tendency for undesired fiapping modes to occur in the upper region of the structure.

Referring further to the above discussion concerning the desirability of controlling or limiting the elastic vibration of the laterally extending member, it should be noted that such limitation is very often largely a function of the limitations of the material and construction of such lateral member. It has been found that if the lateral member, such as superstructure 58, is made of high-strength material, without stress raisers such as sharp notches or gross surface imperfections, it can actually be driven to substantial elastic vibration amplitude without suffering harm therefrom. Moreover, if a fairly high-Q material is used, the vibration of the lateral system is not deleterious to the energy of the system.

In some instances it has been found that, with proper control, these lateral vibrations can be effectively utilized, with important advantages accruing. For example, it is possible to deliberately generate a wave pattern in a lateral member (superstructure 58) such as by use of the oscillator 60, so that this wave pattern is effective to drive a plurality of earth penetration units from a single or concentrated source. Under these conditions, the superstructure 58 can function as an intermediate wave transmission system, or it can be the primary system in which the elastic vibrations are generated. In the latter case the depending pile units, or earth penetration members, may vibrate primarily as lumped constants, without necessarily having wave patterns or resonance within their individual dimensions.

It is of course desirable that superstructure 58 be fairly robust in size if it is to be a major wave transmission line. This, however, is usually fairly easy to provide. Accordingly, this invention can be practiced by deliberately employing a lateral vibration system. In aid of this function, it is desirable to proportion the lateral member and the vertical member so that their impedances are fairly well matched where the longitudinal members couple into the lateral member. This gives optimum power transfer. For example, if the longitudinal members are intended to have a longitudinal wave system, then one desirable arrangement is a fairly low impedance at the connection wherein the upper end of each vertical member is a longitudinal antinode, and the adjacent region of the lateral member is an antinode for a lateral wave of the same frequency.

Thus it can be seen by the various embodiments described in this application, that by the use of sonics, complex structures can be driven into the earth. In this manner much of the conventional intermediate fabrication steps of erecting all of the longitudinal members and then constructing a superstructure on top of them can be eliminated by sonically driving, and locating, and thus installing complex structures as a unit. In the various embodiments described, the undesirable laterally extending parasitic vibrations, when they occur, are substantially controlled and precluded such that a waste of energy is not present and the energy produced by the oscillating generator can be transmitted directly to the longitudinal members and the driving expedited.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to preferred embodiments, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated and in their operation may be made by those skilled in the art, without departing from the spirit of the invention; therefore,

it is intended that the invention be limited only as indicated by the scope of the following claims.

What is claimed is:

1. The method of driving into a medium a complex structure characterized by a plurality of longitudinal pile members and an asymmetrical mass comprising:

providing a bias to said complex structure to counteract the effect of said asymmetrical mass whereby said structure is substantially symmetrical;

generating longitudinal resonant elastic vibrations in said longitudinal members wherein the vibrations imparted to each of said longitudinal members is generated independently of the vibrations generated in the other longitudinal members; and

discontinuing said vibrations when said structure has reached the desired position.

2. The method of driving into a medium a complex structure characterized by a superstructure and a plurality of longitudinal pile members attached thereto comprising:

generating a longitudinal resonant elastic vibration in each of said pile members, said vibrations being independent of the vibrations generated in said other pile members; and

3. An apparatus for driving a structure characterized by a plurality of longitudinal members having an asymmetrical mass attached thereto which comprises:

at least one sonic oscillator operable at a longitudinal resonant frequency of said members and wherein each of said longitudinal members has a sonic oscillator mounted thereon; and

a balancing bias corresponding to said asymmetrical mass, whereby said structure is substantially symmetrical to permit a resonant standing wave to be imparted to said longitudinal members.

4. An apparatus for driving a complex structure char acterized by a superstructure and a plurality of pile members attached thereto comprising:

a plurality of sonic oscillators operable at the longitudinal resonant frequency of said pile members, each of said pile members having mounted thereon one of said sonic oscillators.

5. The method of driving into a medium complex structural elements characterized by a longitudinal member with an unbalanced laterally extending mass which comprises:

providing a balancing laterally extending mass on said longitudinal member opposite said unbalanced mass;

bringing one end of said element into engagement with the earth;

generating a longitudinal resonant elastic vibration in said member; and

discontinuing said vibration when said member has penetrated to the desired depth.

6. The method of driving into a medium complex structural elements characterized by a longitudinal member with a laterally extending mass which comprises:

providing an acoustic rectifier between said longitudinal member and said laterally extending mass;

bringing one end of said element into engagement with the earth;

generating a longitudinal resonant elastic vibration in said longitudinal member; and

discontinuing said vibration when said member has penetrated to the desired depth, whereby transmission of vibrational energy to said laterally extending mass is substantially prevented.

7. The method of driving into a medium complex structural elements characterized by at least one longitudinally extending member having a laterally extending mass, said mass being adapted to be excited to a fiexural mode of elastic vibration when said longitudinal member is excited longitudinally by vibration which comprises:

providing at least one vibration damper for said laterally extending mass whereby the frequency response level of said laterally extending mass is at a substantially different level from that of said longitudinally extending member;

discontinuing said vibration when said member has penetrated to the desired depth, whereby generation of resonant flexural modes of vibration in said laterally extending mass is substantially prevented.

8. The method according to claim 7 in which said vibration damper comprises a container containing a mass of loose material whereby high internal friction is provided.

9. The method according to claim 7 in which said vibration damper is located within said laterally extending mass and is adapted to provide high internal friction.

10. The method according to claim 7 in which there are a plurality of longitudinally extending members.

11. The method according to claim 7 wherein said laterally extending mass is constructed of a material which has high internal damping.

12. An apparatus for driving a longitudinal member having an asymmetrical laterally extending mass which comprises:

a sonic oscillator operable at a longitudinal resonant elastic frequency of said longitudinal member; and

a balancing mass corresponding to said asymmetrical laterally extending mass attached to said longitudinal member, whereby said longitudinal member is balanced.

13. In a structure having a plurality of longitudinal members adapted to be driven into the ground and a laterally extending superstructure thereon, that improvement which comprises:

at least one sonic oscillator adapted to transmit cyclical sonic longitudinal resonant frequencies to said longitudinal members and coupled to said longitudinal members; and

a decoupling attachment between each of the longitudinal members and said superstructure, said decoupling attachment being adapted to prevent sonic vibrations from being transmitted from said longitudinal members to said superstructure during onehalf of each cycle.

14. In an apparatus for driving a plurality of longitudinal members into the earth and a laterally extending superstructure thereon, that improvement which comprises:

at least one sonic oscillator adapted to transmit longitudinal cyclical sonic resonant frequencies to said longitudinal members and lateral frequencies to said superstructure to produce velocity antinodes in said superstructure; and

a mass having internal friction located at said velocity antinodes whereby said velocity antinodes in said superstructure are suppressed.

15. In an apparatus according to claim 14 in which said mass comprises a container with loose particles located therein.

16. In an apparatus for driving a plurality of longitudinal members having a superstructure thereon into the earth, that improvement which comprises:

damping means located within said superstructure at said velocity antinodes whereby said velocity antinodes are suppressed.

17. The method of driving into the earth a longitudinal member which comprises:

bringing one end of said member into engagement with the earth;

generating a longitudinal resonant elastic vibration in said member;

applying a lateral bias to said member whereby the direction ofpenetration of said member is changed; and

discontinuing said vibration and said bias when said member is at the desired depth and orientation.

18. The method of driving a complex structure into the earth, said structure being characterized by a plurality of longitudinal pile members having a plurality of laterally extending interconnecting portions, the steps comprising:

generating longitudinal elastic vibrations in each of said longitudinal pile members at an overtone of the resonant frequency of corresponding ones of said pile References Cited UNITED STATES PATENTS Bodine 17556 X Bodine 175-49 Muller 17519 X Muller 17519 X Bodine 17556 X Taylor 61-53.5

CHARLES E. OCONNELL, Primary Examiner. R. E. FAVREAU, Assistant Examiner.