Abstract:
A casting guide and a method of making a concrete pile using the casting guide, the casting guide including a casting guide end plate, at least two lock rod forms including a first set of crosswise through-holes, and at least two lock socket forms including a second set of crosswise through-holes. The first and second sets of crosswise through-holes configured to removably receive a casting guide pin extending substantially across the casting guide end plate and interconnecting the crosswise through-holes the lock rod forms or lock socket forms when the casting guide is inside a casting chute.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a Divisional application of co-pending U.S. application Ser. No. 14/190,847, filed on Feb. 26, 2014, which is a divisional application of U.S. application Ser. No. 12/100,788, filed on Apr. 10, 2008, which is related to and claims priority to application Ser. No. 60/907,710, entitled “JOINT FOR REINFORCED CONCRETE PILE SECTIONS,” filed on Apr. 13, 2007, the contents of which are incorporated herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to joints for concrete piles, methods for making concrete pile joints, and methods for joining concrete piles using those joints. 
     2. Description of Related Art 
     The most common pile used in many parts of the world, such as in Scandinavian countries, is the pre-cast reinforced concrete pile. Because of manufacturing, structural, transportation, installation, and other limitations associated with concrete piles, the length of the piles is often limited to a pre-determined length. Depending on the situation, it is often necessary to join, or splice, two piles end-to-end at a construction site when an individual pile section is not long enough for a particular application. However, joining discrete concrete piles presents several difficult challenges, such as proper alignment of the pile sections, maintaining continuity of strength, mechanical performance, and other properties. Alignment is critical to prevent slippage, bending stresses, and other problems associated with pile splices. 
     A concern that is often associated with the use of mechanical splices for piles is the ability of the splice to transmit stress waves of the impact hammer from the upper segment of the pile to the lower segment. A splice with inadequate transmissivity of stress waves would hinder the ability to test the pile for integrity and capacity using the Pile Driving Analyzer (PDA), which is a widely used pile-testing tool in the United States. 
     A number of solutions have been proposed for splicing reinforced concrete piles. A common method of splicing piles is to provide the ends of the piles to be joined together with four longitudinal locator and locking pins with crosswise holes or grooves that are inserted into the corresponding recesses in the opposing pile ends after the piles have been placed on top of each other in order to be spliced. The pile splice is locked in position by driving locking pins or keys from the side through the crosswise holes or grooves positioned at the corresponding positions at the pile ends. This method of joining piles together has, however, proved to be complicated to manufacture, and it is difficult to make it fit accurately because of the variations in the dimensions of the joint end plates that cover the ends of the piles. 
     Additionally, a problem with all known pile splices is how to position the joint squarely on top of the pile in connection with casting because they can only be locked to the concrete casting chute at two corners (i.e., the top corners that are visible and accessible). This type of splice varies in detail. However, they all exhibit numerous drawbacks. First, the structure of known joints is complicated, expensive to manufacture and unreliable in service. Second, both the female lock socket and male lock rod must be made of solid steel by machining, which results in considerable wastage of raw material and makes the final product heavy and expensive. Additionally, the lock socket is a closed construction easily penetrated by water, which then freezes at sub-zero temperatures, meaning that pile splicing cannot be carried out under certain conditions. The removal of ice is highly complicated in pile-driving conditions at a construction site. Because of those problems, attempts have also been made to develop a range of joints for splicing reinforced concrete piles together. 
     U.S. Pat. No. 3,884,589 discloses an exemplary locking joint for concrete piles having joined sections. The facing end surfaces of the sections to be joined are made of metal and have outwardly projecting pins and/or openings arranged therein, the openings communicating with the pin receiving spaces to receive the pin from a next pile section. The pin receiving spaces have metal walls and each pin has a transverse hole therethrough to receive a wedge device to be inserted through the hole in the pin through a bore projecting through the side of the pile section into which the pin is inserted, thereby to hold the ends of the pile sections in firm abutting relationship as previously described. The locking joint is mainly characterized in that the wedge device is held in locking position in the bore and in the transversally extending hole through the pin by locking means located in the bore adjacent the side surface of the pile section and on the wedge device itself. 
     U.S. Pat. No. 5,032,041 discloses a joining device for concrete piles having a “through-going cavity” (9) that traverses the width of the concrete pile and that allows one to insert a wedge (13) to secure two concrete pile ends together. As shown in FIG. 9 of that patent, the wedge can be easily reversed by driving it back out of the key hole. 
     U.S. Pat. No. 4,009,550 discloses a concrete pile joint box that is square- or box-shaped, illustrating what many concrete pile joints look like today. 
     U.S. Pat. No. 3,313,560 discloses a pre-tensioning wire anchoring system for concrete pre-compressed structures (concrete pipes are illustrated), and teaches using a flat socket member adapted to being placed at the end of a concrete form, the socket member having multiple spaced-apart through holes for insertion of a tensioning wire. 
     EP 1,288,382 discloses a joint for joining reinforced concrete pillars together, and requires that the projecting locking part have an annular groove, a connecting element that includes an annular groove, and a spring-like locking element which locks in the two grooves. 
     Prior art concrete piles use concrete anchor bars to provide a means to attach and/or align joints. However, anchor bars of that type are not suitable for precision component purposes. 
     It is not uncommon to observe wet, muddy, and icy conditions at construction sites where concrete piles are used. Because concrete piles are often placed directly on the ground before use at a site, the transverse holes for the locking pins often become clogged with debris, ice, mud, pebbles, etc. However, if a straight path is present to the other side, the debris can simply be pressed through. Ice is a particular concern for concrete piles, as mentioned above, because the spliced sections often become unstable. Therefore, pin-receiving tubes that extend straight through from one side of the pile to the other present a significant prevention in lost resources due to unusable or damages to concrete piles. The aforementioned prior art pile joints and methods of joining piles fail to address those, and other known problems associated with typical concrete piles. 
     BRIEF SUMMARY OF THE INVENTION 
     In view of the lack of suitable solutions to the aforementioned problems offered in the prior art, it should be apparent that there exists a need for a concrete pile joint that can be manufactured to high tolerance levels (preferably achieved through use of robotic manufacturing) at minimum cost that, when used to splice concrete pile sections, produces a highly reliable splice. The purpose of the present invention is to provide a simpler stiff pile splice for use in reinforced concrete piles by eliminating the drawbacks exhibited by known similar splices. More specifically, the invention seeks to provide a stiff pile splice with low cost of materials and labor in production. 
     Another purpose of the invention is to provide a pile splice with a locking system that is not loosened even by a large number of impacts. 
     An object of the invention is to provide a pile splicing solution to which locking structures may be threaded or welded, and to provide a locking joint that can be fixed to a concrete casting chute at all the four corners thanks to parallel crosswise holes extending all the way across the structure. 
     Another object of the invention is to provide a joint that allows for superior alignment of piles and multiple splicing scenarios for higher chance of success in driving piles. 
     Another object of the invention is to use robotic welding and machining equipment to ensure very tight tolerances so that splices are very tight at the joints. 
     Another object of the invention is to provide a splice with four corners of equal stress, because such a design results in excellent alignment of the pile sections. If the stress is uneven, then one could observe deflection between pile sections. If the splice is loose (not tight as compared to installation conditions), then it would “clutter” during installation (i.e., pile hammering). If splice is separated and if impacted, this would increase the risk that the pile will break. Also, without the excellent alignment provided by the present design, the pins can come loose or fall out altogether. 
     Briefly described, those and other objects and features of the present invention are accomplished, as embodied and fully described herein, by a joint for a concrete pile section having a first end plate for connecting to the concrete pile; a plurality of spaced apart lock rods attached to and extending substantially perpendicular to the first end plate; a plurality of spaced apart lock sockets attached to and extending substantially perpendicular to the first end plate, wherein each of the plurality of lock sockets has a cavity portion and axially-aligned crosswise through-holes on opposite walls of the cavity; and at least one pin-receiving member interconnected between the crosswise through-holes of at least two of the plurality of lock sockets, wherein the member extends substantially across the first end plate. 
     The joint includes a pin-receiving member that extends a distance into one of the crosswise through-holes. The pin-receiving member includes a first pin-receiving portion extending from a first peripheral edge of the first end plate into one of the crosswise through-holes; a second pin-receiving portion extending between two crosswise through-holes and substantially axially-aligned with the first pin-receiving portion; and a third pin-receiving portion extending from a second peripheral edge of the first end plate into one of the crosswise through-holes and substantially axially-aligned with the first and second pin-receiving portions. 
     The joint may further include a step edge formed circumferentially at the insertion opening of the at least two lock sockets where they attach to the first end plate. An anchoring device may be attached to at least one of the plurality of lock rods and at least one of the plurality of lock sockets, wherein the at least one anchoring device extends substantially perpendicular to the first end plate. The plurality of lock rods are preferably conical shaped. The plurality of lock rods includes an annular groove at a portion where the lock rods attach to the first end plate. A protective cap may be inserted into the cavity of the plurality of lock sockets. Another protective cap may be inserted into an end of the pin-receiving member. A protrusion may be attached to the protective cap for inserting into a recess. 
     Briefly described, the objects and features of the present invention are also accomplished, as embodied and fully described herein, by a method for making a joint for a concrete pile, which includes the steps of: attaching to a first end plate a plurality of spaced apart lock rods extending substantially perpendicular to the end plate; attaching to the first end plate a plurality of spaced apart lock sockets extending substantially perpendicular to the first end plate, wherein each of the plurality of lock sockets has a cavity portion and axially-aligned crosswise through-holes on opposite walls of the cavity; attaching at least one pin-receiving member to the first end plate, wherein the pin-receiving member interconnects the crosswise through-holes of at least two of the plurality of lock sockets, and wherein the member extends substantially across the first end plate. The method further includes attaching the joint to a concrete pile, and splicing the pile joint with another pile joint by removably inserting a locking pin into the pin-receiving member, crimping an end of the pin-receiving member to secure the locking pin. 
     The concrete pile to which the joint is attached preferably includes a square base. The connecting ends of driven reinforced concrete piles feature box-like or plate-like parts to which the locking structures are attached by welding using robotic welding machines. This allows the splice to withstand forces acting on it from all directions. The tight tolerances are provided by precision machining and robotically welding components together. 
     In a concrete pile splice according to the present invention, the locking parts are provided with a suitable crosswise tube to permit the locking pin being driven into the tube-like tunnel of the locking joint to press the lock rod and lock socket firmly against each other; the lock sockets are interconnected with tube-like parts; the locking pin is round in cross-section; and the locking pin is capable of being driven into the tube-like tunnel from the side. The locking pin is preferably beveled at the tip, so that the small diameter at the tip starts insertion, and when fully inserted, the pin is in a double shear plane arrangement. It takes up to seven tons of jack pressure to remove the fully inserted pin. This type of splice is desirable and necessary in some application where, for example, five 50-ft piles are joined together and driven into soft material to form a footing. 
     By design, the dimensional characteristics of the present splice is such that the locking pins cause positive compression at the joint, which uniquely improves both the magnitude of the contact surface area and the degree of tightness of the contact area of the upper and lower pile segments. The results of PDA tests performed on piles joined with the present splice did not show warning signs that would be expected in the case of discontinuous piles. The presence of the splice was not discernable on the resultant force and velocity wave traces, which are typically displayed on the PDA computer screen during testing. However, further scrutiny of the measurements showed that when the force waves were broken up into upward-moving and downward-moving components, the presence of the splice was evident in the upward-moving wave component only. The magnitude of the effect of the presence of the splice on the wave trace was within the range of those observed for typical anomalies for similar piles. 
     The PDA Integrity Factor (β) of piles using the present invention was 100 percent. Generally, the β value of less than 80 percent would raise concern for potential lack of continuity (breakage) of a pile. A broken pile would have β values of significantly less than 80 percent. Correctly so, piles using the subject splice approached the state of continuum by virtue of the positive compression the joint afforded by the tight design of the locking pins, and as a result demonstrated β values of 100 percent. 
     The Case pile Wave Analysis Program (CAPWAP) evaluations of PDA records obtained on piles using the present invention provided near-perfect match of the measured and computed force curves, with reasonably good Match Quality of less than 3.0. Noteworthy, it is nearly impossible to perform a successful CAPWAP evaluation on PDA data from a broken pile. The corroborative extent of the capacities of the spliced pile based on the two methods (PDA and CAPWAP), along with measured excellent energy transmission through the splice, demonstrates the ability of the subject splice to foster continuum behavior of spliced piles. 
     The splice in accordance with the present invention offers a number of additional benefits. Thanks to simple construction, substantial savings are achieved in the cost of materials and labor. As a result, a non-loosening locked splice is accomplished even after a large number of impacts. At the same time, this construction prevents the problems caused by water freezing in the lock socket on the pile-driving site when piles are spliced. Additionally, the invention provides a locked splice that does not have to be anchored in the end plate using load-bearing welds. 
     In one embodiment of the invention, the locking pin is round with no shoulders and conical in shape at both ends, so that the cross section is identical with that of the crosswise holes substantially in the locking parts; the tube-like parts in the splice form a crosswise tunnel in the pile that serve as a casting formwork and as an access route for the locking pin: the crosswise tubes in the splice are positioned in the lock rod in such a way that they pre-tension the splice as a result of the deflection of the locking pin. The round, shoulderless locking pin may be conical at one end only. 
     In a second embodiment of the invention, the first piece to be joined includes a reinforced concrete pile with the connecting device at its end consisting of a round protrusion with a round through-hole such that the other piece to be joined is a rock point with connection point compatible with the splicing parts in terms of cross section; the connecting parts of the reinforced concrete pile and the rock points are interlocked with a locking pin supported on the joint placed eccentrically at the distance required for pre-tensioning. The locking pin can also be locked later by bending the wall of pin-receiving tube to prevent it from being dislodged. 
     With those and other objects, advantages and features of the invention that may become hereinafter apparent, the nature of the invention may be more clearly understood by reference to the following detailed description of the invention, the appended claims and to the several drawings attached herein. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a schematic drawing showing an axonometric view of the splicing ends of two reinforced concrete piles each with a compatible joint according to the present invention; 
         FIG. 2  is a schematic drawing showing a partial cross-sectional view of two compatible joints in a pre-connecting position according to the present invention; 
         FIG. 3  is a schematic drawing showing a partial cross-sectional view of the ends of two joined reinforced concrete piles with compatible joints interconnected according to the present invention; 
         FIG. 4  is a another schematic drawing showing a partial cross-sectional view of the ends of two joined reinforced concrete piles with compatible joints interconnected according to the present invention; 
         FIG. 5  is a schematic drawing showing a lateral cross-sectional view of the vertical section of the joints between two reinforced concrete piles in accordance with another embodiment of the present invention; 
         FIG. 6  is a schematic drawing showing a vertical cross-section of the joints in  FIG. 5  after they are interconnected. 
         FIG. 7  is a schematic drawing showing a partial cross-section of one part of the joint according to the present invention; 
         FIG. 8  is a schematic drawing showing a partial vertical cross-section of the reinforced concrete pile splice accordance to another embodiment of the present invention; 
         FIG. 9  is a schematic drawing showing a cross-section of one part of the joint according to the present invention; 
         FIG. 10  is a schematic drawing showing a lateral view of one embodiment of a pin according to a preferred embodiment of the present invention; 
         FIG. 11  is a another schematic drawing showing a partial cross-sectional lateral view of the joint according to the present invention; 
         FIG. 12  is a schematic drawing showing a section of a reinforced concrete pile at the joint end according to the present invention; 
         FIG. 13  is a schematic drawing showing a perspective view of a casting guide according to another embodiment of the present invention; 
         FIG. 14  is a schematic drawing showing a perspective view of the casting guide of  FIG. 13  and joint according to the present invention positioned together inside a casting chute prior to a concrete pour; 
         FIG. 15  is a schematic drawing showing a vertical partial cross-sectional elevation view of the casting guide, joint, and casting chute of  FIG. 14  according to the present invention; and 
         FIGS. 16 a  and 16 b    are schematic drawings showing a vertical elevation view of the casting guide pin according to one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Several preferred embodiments of the invention are described for illustrative purposes, it being understood that the invention may be embodied in other forms not specifically shown in the drawings. 
     Turning first to  FIG. 1 , shown therein is a schematic drawing of an axonometric view of the splicing ends of two reinforced concrete piles  1   a ,  1   b  each with a compatible joint according to the present invention. The two reinforced concrete piles  1   a ,  1   b  are to be joined together with the pile ends close to each other but still not touching. Piles  1   a ,  1   b  are primarily made of concrete, in addition to which they contain concrete reinforcement bars (“rebars”) (as best seen in  FIG. 14 ). 
       FIG. 1  shows the structure of the joints  2   a ,  2   b  of the reinforced concrete piles  1   a ,  1   b  in more detail. Each of the joints  2   a ,  2   b  includes an end plate  3   a ,  3   b , respectively, which may or may not include edges  12   a ,  12   b , as well as welded anchoring devices  4   a ,  4   b , lock rods  5   a ,  5   b , lock sockets  7   a ,  7   b , peripheral locator tubes  8   a ,  8   b , transverse locator tubes  9   a ,  9   b , and locking pins  10   a ,  10   b . The number of components shown in  FIG. 1  is for illustrative purposes only. A typical joint will include two lock rods  5  and two lock sockets  7  spaced apart at the corners of the end plate  3 . 
     As shown in  FIG. 1 , the joint  2   a  of the upper reinforced concrete pile  1   a  includes the end plate  3   a  featuring suitable holes  11   a  for the insertion of lock rods  5   a  and lock sockets  7   a  and forming, together with the edges  12   a  being slightly bent over, a box-like structure that is adapted to being positioned at the end of a rectangular or square concrete pile. The edges  12   a  may be created using a press, and are preferably about ⅜-inch in height around the entire periphery. They are non-structural components and are used for stiffness and casting. One of ordinary skill will appreciate that the end plates  3   a ,  3   b  of the present invention are not limited to being square- or box-shaped, but could encompass other shapes as well. Typical sizes for the end plate  3  are well known in the industry by those skilled in the art. 
     Fixed to the opposite sides (or corners) of the end plate  3   a , are the lock sockets  7   a , aligned with the holes  13   a  in the end plate  3   a , while fixed to the opposite sides (or corners), are the lock rods  5   a , each provided with a crosswise hole  6   a  in the protruding section. The inner surfaces of the protruding lock rods  5   a  extend through the end plate  3   a  to which the anchoring devices  4   a  are welded to provide bonding. In a preferred embodiment, the anchoring devices  4   a  are rebar. 
     The lock rods  7   a  are interconnected by the peripheral locator tubes  8   a , and the transverse locator tube  9   a . Similarly, the lock sockets  7   b  are interconnected by the peripheral locator tube  8   b , and the transverse locator tube  9   b  welded to the joint  2   b  of the lower reinforced concrete pile  1   b . The lock sockets  7   b  have a base to which the anchoring devices  4   b  (here, again, rebar) have been welded to provide bonding to the splice. The anchoring devices may be arranged in single pieces or multiple pieces. The lock rods  5   b  have been attached to the opposite sides (or corners) of the end plate  3   b . The anchoring devices  4   b  are fixed to the lock rods  5   b  by welding or with threads. 
     The peripheral locator tubes  8   a , and the transverse locator tube  9   a , are generally coaxially aligned. The peripheral locator tubes  8   b , and the transverse locator tube  9   b , are also generally coaxially aligned. 
     Although not shown in  FIG. 1 , the lock rods  5   a ,  5   b  and lock sockets  7   a ,  7   b  can be placed on the same sides or at opposite corners of the respective end plates  3   a .  3   b.    
     As discussed previously, it is important to use economical materials in the manufacture of the joints  2   a ,  2   b . To make the least expensive end plates  3   a ,  3   b  as possible, they are essentially a non-structural component of the joints  2   a ,  2   b . Their main role is for alignment of the locking assemblies—the lock rods  5   a ,  5   b , and lock sockets  7   a .  7   b . However, lower cost end plates  3   a ,  3   b  tend to have worse tolerances across the surface. The goal is to ensure adequate eccentricity of the two (male to female) peripheral locator tubes  8   a ,  8   b  and transverse locator tubes  9   a ,  9   b  so as to accept the locking pins  10   a ,  10   b  and pull the mating joints together. The present invention achieves that goal, and results in a splice that efficiently transmits energy along the entire length of the spliced concrete pile, such as during pile driving, without damaging the pile. 
     The lock sockets  7   a ,  7   b  are toleranced by the step edge that is lathed for purpose of fitting onto the end and into the end plates  3   a ,  3   b . Because the lock sockets  7   a .  7   b  pass through the end plates  3   a ,  3   b , the lock sockets  7   a ,  7   b  can physically contact the male lock rods  5   a ,  5   b . This simple nuance reduces the cumulative tolerance path that eventually affects the range of eccentricity of the crosswise holes  6   a ,  6   b , and the peripheral and transverse locator tubes,  8   a ,  8   b ,  9   a ,  9   b . It is preferable that offsetting the crosswise holes  6   a ,  6   b  relative to the peripheral and transverse locator tubes  8   a ,  8   b ,  9   a ,  9   b  provides about a few hundredths of an inch eccentric offset or more, preferably about 2 millimeters. 
     Moreover, the lock sockets  7   a ,  7   b  use the end plates  3   a ,  3   b  as a placement constraint as well. With this pass-through approach to the lock socket  7   a ,  7   b  part of the device made possible by the peripheral and transverse locator tubes  8   a ,  8   b ,  9   a ,  9   b  extending across the entire width of the end plates  3   a ,  3   b , the device is capable of being manufactured to the same tolerance, i.e. not relying on quality of the end plates  3   a ,  3   b , but on the quality of the process steps used to weld the lock sockets  7   a ,  7   b , and lock rods  5   a ,  5   b , to the end plates  3   a ,  3   b.    
     Turning now to  FIG. 2 , shown therein is a schematic drawing of a partial cross-sectional view of two compatible joints  2   a ,  2   b  in a pre-connected or pre-spliced position according to the present invention. Extending through the end plate  3   a , there is attached to the upper pile a lock socket  7   a , to which the generally coaxially-aligned peripheral locator tube  8   a  and the transverse locator tube  9   a  are attached. Placed in the lock socket hole  23  of the lock socket  7   a , the peripheral locator tube  8   a  and the transverse locator tube  9   a  provide a dimension  18   a  that is suitably greater than the dimension  18   b , thereby providing the necessary pre-tensioning of the splice by the action of the deflection of the locking pin  10   a  when it is inserted into the peripheral locator tube  8   a  and the transverse locator tube  9   a  from the side of the pile  1   a.    
       FIG. 2  also shows the relative dimensions of the joints  1   a ,  1   b  indicated by alphanumeric symbols  15   a  and  15   b , which are measured from the adjoining surfaces of the respective piles  1   a ,  1   b .  FIG. 2  shows that the dimension  15   a  in the lock socket  7   a , and the dimension  15   b  in the lock rod  5   b , can be machined highly accurately to the required size in order to ensure adequate tightness of the splice. This provides optimum tightness because the dimension  15   a , in a preferred embodiment of the invention, is a few tenths of a millimeter greater than the dimension  15   b , forcing the locking pin  10   a  to deflect when it is inserted and the two piles are joined together, which creates a very tight splice that is difficult to detect using traditional dynamic pile testing techniques, as previously described. The dimensions  15   a ,  15   b  are important for the proper in-service performance of the lock socket  7   a  and the lock rod  5   b . The actual dimensions  15   a ,  15   b  for specific applications can be ascertained by experimentation. 
       FIG. 2  also shows that the splicing half  2   a  of the upper pile  1   a  includes a protective cap  16  and a protective cap  17  to prevent the ingress of concrete into the locking means during casting. The protective cap  17  features a protrusion  17   a , which makes it possible to bend the wall of the tube  8   a  so as to prevent the locking pin  10   a  from being dislodged when the pile  1   a  is driven into the ground. 
     The peripheral locator tube  8   a  and the transverse locator tube  9   a  form a crosswise tunnel  19   a  extending across the pile  1   a . As a result, a casting tool may be used to position the joint  2   a  squarely perpendicular relative to the longitudinal direction of the pile  1   a  (i.e., no bending along the length of the end plate  3   a ). Additionally,  FIG. 2  shows that the lock rod  5   b  contains a groove  14  sized to the dimension  15   b  from the centre line of the crosswise hole  6   b.    
     Turning now to  FIG. 3 , shown therein is a schematic drawing of a partial cross-sectional view of the ends of two joined reinforced concrete piles  1   a ,  1   b  (i.e., a splice) with the compatible joints  2   a ,  2   b  interconnected according to the present invention using two locking pins  10   b  in their final inserted position. The lengths of the two locking pins  10   b  is selected so as to ensure that both can be driven into the final positions shown while preventing the other pin from being dislodged. This can be accomplished if the total lengths of the two pins is less than the combined length of the peripheral locator tubes  8   a  and the transverse locator tube  9   a    FIG. 3  also shows that any variation in the thickness tolerances of the end plates  3   a ,  3   b  does not affect the tensioning of the splice. The splice is designed so that the end plates  3   a ,  3   b  only serve as a locator for the lock socket  7   a  and lock rod  5   b . Additionally,  FIG. 3  shows that the lock rod  5   b  has a conical head  5   c.    
       FIG. 4  is a schematic drawing of a partial cross-sectional view of the ends of two joined reinforced concrete piles  1   a ,  1   b  with compatible joints  2   a ,  2   b  interconnected according to the present invention using the locking pin  10   b  secured by bending the wall  20  of the peripheral locator tube  8   a  in order to prevent the locking pin  10   b  from being dislodged. The wall  20  of the peripheral locator tube  8   a  is inserted into position using a suitable tool (e.g., hammer) by making use of the groove  21  when the piles  1   a ,  1   b  are spliced.  FIG. 4  shows that the lock socket  7   a  includes a cavity  22  of a size that accepts the lock rod  5   b . Additionally,  FIG. 4  shows that the lock socket  7   a  can also be made of a tube with the required crosswise hole for connecting or fixing the peripheral locator tube  8   a  and the transverse locator tube  9   a.    
     Turning now to  FIG. 5 , shown therein is a schematic drawing of a lateral cross-sectional view of the vertical section of the joints  2   a ,  2   b  between two reinforced concrete piles  1   a ,  1   b  in accordance with a another embodiment of the present invention, in which the lock rod  5   a  is positioned in the lock socket  7   b  of the concrete pile  1   b  such that the crosswise hole  6   a  of the lock rod  5   a , and the crosswise tunnel  19   a  extending through the lock socket  7   b , have an eccentric disposition relative to each other. 
       FIG. 6  is a schematic drawing of a vertical cross-section of the joints  2   a ,  2   b  in  FIG. 5  interconnected such that the locking pin  10  is driven through the crosswise tunnel  19   a  of the transverse locator tube  9   a  that extends through the lock socket  7   b  and the crosswise hole  6   b  of the lock rod  5   a . The locking pin  10  is preferably made from a more malleable steel than the components into which it is inserted. The eccentricity of the through-openings causes the more malleable locking pin  10  to cold-form and deflect as shown (exaggerated for emphasis) a few hundredths of an inch or more. The shouldered or tapered end of the pin facilitates entry into the transverse locator tube  9  even as the pin is being deflected upward as it traverses through the crosswise hole  6  of the lock rod  5 . Because of the deflection in the locking pin  10  in the splice, the concrete piles  1   a ,  1   b  are pre-tensioned, making the splice very strong and resistant to lateral and longitudinal movement of the spliced pile sections. 
       FIG. 7  is a schematic drawing of a partial cross-section of one part of the joint  2   b  according to the present invention. The structure of the lock socket  7  of the reinforced concrete pile  1   b  consists of the sleeve  25  and is attached to the hole  11  in the end plate  3 . Preferably, use is made of the piece  24  detached from the end plate  3  for making the hole  11  by welding it to serve as a base for the lock socket  7  A peripheral notch  26  is provided in the side of the sleeve  25 , forming a shoulder and making it possible to position the sleeve  25  in the hole  11  accurately flush with the surface of the end plate  3 . This ensures that the holes  27  of the sleeve  25  are positioned with great accuracy to achieve the preferred eccentricity of the various through-openings described above. 
       FIG. 8  is a schematic drawing of a partial vertical cross-section of the concrete pile splice accordance to another embodiment of the present invention in which the splicing method involves anchoring devices  4  (rebar, in this case) welded, from the side, with welds  28  to the structures of the joints  2   a ,  2   b  ( FIG. 1 ). The welds  28  ensure a strong bond for the anchoring devices  4   a ,  4   b . There may be one, two, three, etc., rebars per socket; it is the overall cross sectional amount of steel as compared to the pile that is the important consideration is determining the number of rebars. 
       FIG. 9  is a schematic drawing of a cross-section of one part of the joint  1   a  according to the present invention, in which the notch  26  is provided in the end plate  3   a  to prevent the water contained in the concrete from leaking into interior spaces within the joint  2   a , causing potential damage. 
       FIG. 10  is a schematic drawing of a lateral view of one embodiment of a locking pin  10  according to the present invention. The locking pin  10  may have a textured surface  29  provided at the surface (or part of the surface) of the locking pin  10  to further enhance the retention of the locking pin  10  when it is inserted. 
       FIG. 11  is a schematic drawing of a partial cross-sectional lateral view of a splice according to the present invention, in which a retaining spring  30  is provided at the edge of the peripheral locator tube  8   a  and partially inside the crosswise tunnel  19   a  extending through the lock socket  7   a  to further improve the retention of the locking pin  10  when it is inserted. 
       FIG. 12  is a schematic drawing of a section of a concrete pile  1   a  at the joint  2   a  according to the present invention, looking at the side of the joint  2   a  that is in contact with the end of the reinforced concrete pile. As shown in the figure, cable through-holes  31  are provided on the end plate  3   a  for accepting pre-tensioning or pre-stressing cables  47  (as best seen in  FIG. 14 ) that run through the length of the concrete piles. 
       FIG. 13  is a schematic drawing of a perspective view of a casting guide  40  according to another embodiment of the present invention. The casting guide  40  includes two lock socket forms  41  extending in one direction from the casting guide plate  45 , and two lock rod forms  43  extending in the opposite direction from the casting guide plate  45 . The two lock socket forms  41  include axially-aligned through-holes  46  into which a casting guide pin  42  is inserted to pin the joint (not shown) at four corners. Also shown are a plurality of cable through-holes  46   a , some of which correspond to the through-holes  31  on the end plate  3   a . At least the bottom two corners of the casting guide plate  45  are preferably rounded. 
       FIG. 14  is a schematic drawing showing a perspective view of the casting guide  40  of  FIG. 13  positioned inside a casting chute  50  according to the present invention along with joints  2   a ,  2   b  as previously described. During manufacture of the piles  1   a ,  1   b , the end plates  3   a ,  3   b  may be positioned inside and attached to the casting chute  50  at all four corners of the joints  2   a ,  2   b  during casting of the concrete piles  1   a ,  1   b , using the casting guide  40 . The use of the casting guide pin  42  to align the casting guide plate  45  and also reach the bottom corners of the joints  2   a ,  2   b  during casting to allow pinning at four corners is a more secure and reliable means of attaching compared to attaching at less than four points. This technique allows one to manufacture every joint  2   a ,  2   b  to the same tolerance. 
       FIG. 15  is a schematic drawing showing a vertical partial cross-sectional elevation view of the casting guide  40  and the joint  2   a  according to the present invention in their respective positions in the casting chute  50 . The end plate  3   a  of the joint  2   a  is shown securely attached next to the casting guide plate  45  so that the end plate  3   a  nearly touches the bottom of the casting chute  50 . While the bottom edge of the casting guide plate  45  may rest upon the bottom of the casting chute  50  when the concrete is poured, it is preferred that the end plate  3   a  be above the bottom of the casting chute  50  by about one-eighth of an inch or so, as shown by G 1 . Similarly, the top of the end plate  3   a  is slightly below the top of the casting guide plate  45  and the top of the casting chute  50  by about one-sixteenth or one-eighth of an inch or so, as shown by G 2 . The casting guide holes should match the holes on the end plate  3   a . The face of the casting guide  40  should basically match the cross-sectional shape of the casting chute, which can vary along its length. Generally, the face of the casting guide  40  has tapered or chamfered walls with rounded corners at the bottom. 
       FIG. 15  also shows the preferred trapezoidal cross-sectional shape of the casting chute  50 , which provides a space at the top of the mold to allow the finished concrete pile  1   a  to be easily slid out of the casting chute  50 . 
       FIG. 15  further shows two of several cable through-holes  31  which allow for the pre-tensioned or pre-stress cables to pass through the end plate  3   a  and the casting guide plate  45 . 
       FIGS. 16 a  and 16 b    are schematic drawings showing vertical front and side elevation views, respectively, of the casting guide pin  42  according to one embodiment of the invention. The casting guide pin  42  is preferably cylindrical-shaped with one side milled flat to form a flat face  42   a . The dimension A exists in the lateral direction. The dimension A-a shows the extent to which the side of the casting guide pin  42  has been milled flat relative to its original size to form the flat face  42   a.    
     The shape of the casting guide pin  42  is such that it easily passes through the male-female overlap region where the eccentricity exists between of the through-openings (as best seen in  FIG. 6 ). During casting, there may be four casting guide pins  42  at each joint, two on each side of the casting guide, holding, respectively, two joints. Once inserted, the casting guide pin  42  is rotated, as illustrated in  FIG. 15 , to securely lock the casting guide plate  45  and end plate  3   a  together before the concrete pour. Because the casting guide pin  42  reaches across the end plate  3   a , only two casting guide pins  42  are needed for each joint  2   a , as described above. Among other things, this arrangement improves the longitudinal alignment of components during casting. 
     The sides and bottom of the casting chute  50  and the casting guide plates  45  are oiled prior to use. The casting guide  40  is positioned in an arbitrary location inside the casting chute  50  with the two rounded corners on the bottom of the casting chute  50 . The location of the casting guide  40  is selected based on a desired length of the pile sections  1   a ,  1   b . The joint  2   a  is attached to one side of the casting guide  40 , and the joint  2   b  is attached to the other side of the casting guide  40 . The casting guide pins  42  are inserted to lock the joints  2   a ,  2   b  to the casting guide  40  by turning the casting guide pins  42  by hand. When the casting guide pin  42  is turned, the pin approaches the dimension A in the longitudinal direction of the pile  1   a , and held in that position by friction. This presses the joints  2   a ,  2   b  against their respective sides of the casting guide  40 . 
     Next, the prestressing cables  47  are pulled through the cable through-holes on the casting guide  40  and the cable through-holes  31  on the end plates  3   a .  3   b  and attached at their respective ends to a hydraulic press which anchors and positions the cables inside the casting chute  50 . A suitable load-locking fastener (not shown) may be attached to the cables where they pass between the two casting guide plates  45  to prevent unwanted movement. 
     Next, ductility or spiral wire  48  is pulled up and secured at the proper spacing to satisfy code requirements. Once the joints  1   a ,  1   b , casting guide  40 , rebar, prestressing cables  47 , and spiral wire  48  are in place, the concrete is poured, vibrated to remove air and to ensure a firm attachment of the joints  2   a ,  2   b  to the respective ends of the piles  1   a ,  1   b . The exposed top of the concrete is finished, and then the piles  1   a ,  1   b  are allowed to cure inside the casting chute  50 . Once the concrete is cured, the prestressing cables may be cut inside the casting guide  40 , and any remaining cable material may be grinded down to the level of the end plates  3   a ,  3   b.    
     Before installing the piles  1   a ,  1   b , the protective caps  16 ,  17  should be removed, which were installed after the piles  1   a ,  1   b  had cured to prevent dirt and concrete from plugging the openings, and to prevent water from entering the locking components of the joints  2   a ,  2   b  and freezing. A driving plate (not shown) is placed over the joint  2   a  so that the driving rig does not damage the joint  2   a  during hammering. Once the pile  1   a  has been hammered into place, but with about four feet extending above the its final position, the mating pile  1   b  is lowered so that the joint  2   b  is parallel with the joint  2   a  and the respective lock rods  5   a ,  5   b  align with the lock sockets  7   a ,  7   b . Four locking pins  10  are then driven into place using a hammer or sledge, each pin inserted into its own peripheral locator tube  8 . 
     Although certain presently preferred embodiments of the disclosed invention have been specifically described herein, it will be apparent to those skilled in the art to which the invention pertains that variations and modifications of the various embodiments shown and described herein may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention be limited only to the extent required by the appended claims and the applicable rules of law.