Splicing of Precast Prestressed Concrete Piles Part I

SPLICING OF PRECAST PRESTRESSED CONCRETE PILES: PART I-REVIEW AND PERFORMANCE OF SPLICES

Robert N. Bruce, Jr., PhD Professor of Civil Engineering Tulane University New Orleans, Louisiana

David C. Hebert Research Assistant Civil Engineering Department Tulane University New Orleans, Louisiana

Effective splicing of prestressed concrete piles can reduce or eliminate many problems associated with the installation of long piles. Proper splicing methods eliminate the need to predict precise pile lengths, and allow extensions of piles when necessary. This report presents the results of an investigation into existing methods presently used in the splicing of prestressed concrete piles. The first part of this report constitutes a review and evaluation on splicing methods developed and used in several areas of the world. The second part of the report, to be published in the next issue of the PCI JOURNAL, describes actual tests and analyses of one of the splices described in this article.

70 Robert N. Bruce, Jr. David C. Hebert

This report represents the results of BACKGROUND an investigation into the present methods of splicing prestressed concrete pil- Effective pile splicing can reduce or ing, and the results of actual tests of eliminate many problems associated certain splices. Each splice included in with the installation of precast pre- the investigation was studied to deter- stressed concrete piles. Among these mine the performance of the spliced problems are the:' section compared to the unspliced con- 1. Need to forecast pile lengths ac- tinuous pile. curately, eliminating waste 2. Extension of piles cast short of the The overall effectiveness of a given length found to be necessary from field splice is dependent upon several fac- results tors. Those factors used in evaluating 3. Cost and difficulty of handling the splices examined in this investiga- and transporting long piles tion were as follows: size range, field 4. Tremendous weight of long piles, time for splicing, approximate cost of and splice, availability, construction usage, 5. Increased cracking incurred with structural integrity, and structural per- excessive handling of long piles. formance. Proper splicing of prestressed piling The data used in the evaluation of eliminates the need to predict the pre- the splices was generated by the auth- cise pile lengths and allows extensions ors for the most part. However, some of piles when necessary. Splicing en- of the data was furnished by the design- ables the use of shorter pile sections; ers and fabricators of a given splice. thereby reducing the weight and length The investigation was limited to of pile that is handled and reducing the those splices commonly used and was danger of cracking due to excessive limited to splices capable of being driv- handling. en by pile driving equipment.

PCI Journal/September-October 1974 71 Chargar, William, Chargar Corporation. ACKNOWLEDGMENTS Corley, W. C., Portland Cement Associa- tion. The work on the project was conducted Davisson, M. T., University of Illinois. by the Department of Civil Engineering Duclos, Louis, Barnard and Burk, Inc. of Tulane University for the Louisiana De- DeFeu A., Cement and Concrete Associa- partment of Highways and in cooperation tion. with the Federal Highway Administration. Edwards, Harry, Leap Associates Inc. On the part of the Louisiana Department Elliott, A. L., California Division of High- of Highways, the work was done under the ways. administrative direction of James W. Lyon, Fellenius, Bengt H., Torchinsky & Associ- Jr., research and development engineer; ates Ltd. Hollis B. Rushing, assistant research and Fuentes, Gabriel Jr., Fuentes Concrete development engineer; and Joseph E. Ross, Piles. concrete research engineer. In addition, Fukushima, Yoshikiyo, Nippon Concrete Sidney L. Poleynard, assistant director; Industries Co. Ltd. David S. Huval, bridge design engineer; Fuller, F. M., Raymond International, Inc. James C. Porter, head bridge designer; and Gerwick, Ben C. Jr., Consulting Engineer. Louis A. Garrido, assistant bridge design Goldberg, Donald, Goodkind & O'Dea, engineer, all contributed greatly to the in- Inc. vestigation. Guild, C. L., American Equipment Fabri- On the part of the Federal Highway Ad- cating Co. ministration, the work was supervised by Hanson, Walter E., Walter E. Hanson Mitchell D. Smith, division bridge engi- Company. neer; and Michael A. Cook, assistant di- Hedman, S., Akermans Verkstad AB. vision planning and research engineer. Henneberger, Wayne, Texas Highway De- The investigation was directed by Dr. partment. Robert N. Bruce, Jr., professor of civil en- Hirsch, T. L., Texas A & M University. gineering, as project investigator. Hunt, Hal W., Associated Pile & Fitting Appreciation is expressed to Prof. John Corporation. K. Mayer of the Tulane University Depart- Jenny, Daniel P., Prestressed Concrete In- ment of Civil Engineering for technical stitute. advice on numerous occasions. Kennedy, Robert H., Castcon, Inc. Gratitude is extended to the Prestressed Kokubu, Masatane, University of Tokyo. Concrete Products Company for time and Leonhardt, Fritz, Consulting Engineer. materials donated to the project. Lin, T. Y., University of California. Appreciation is expressed to the follow- Lyon, Ethyl V., Portland Cement Associa- ing individuals and organizations who have tion. contributed technical background informa- Makita, Hiroomi, Tokyu Concrete Industry tion and data to this investigation: Co., Ltd. Alberdi, T. Jr., Florida Department of Manson, John F., Dravo Corporation. Transportation. Marier, Gaston, Consulting Engineer. Anderson, Arthur R., Concrete Technology Moretto, 0., Bolognesi-Moretto Engineers. Corporation. Moses, Warren, Bayshore Concrete Prod- Andrews, D. A., The Concrete Society ucts Corporation. (England). Mouton, William J. Jr., Consulting Engi- Banks, Paul I., Hawaiian Dredging Com- neer. pany. McCalla, W. T., Hamilton Form Company, Blessey, Walter E., Tulane University. Inc. Brandon, N. R., Concrete Pipe Products Nordahl, Arne, Swedish Institute for Ma- Co. Inc. terials Testing. Broms, Bengt, Swedish Geotechnical Insti- O'Donnell, Keith 0., Department of the tute. Army. Brown, Thane E., Swan Wooster Engineer- Papayoti, G., Raymond International, Inc. ing Inc. Raamot, Tonis, Raamot Associates.

72 Severinsson, S., AB Scanpile. 13. Dowel Splice (USA) Sheppard, David A., Blakeslee Prestressed 14. Macalloy Splice (Great Britain) Concrete. 15. Mouton Splice (USA) Shideler, J. J., Portland Cement Associa- 16. Raymond Wedge Splice (USA) tion. 17. Pile Coupler Splice (USA) Siess, C. P., University of Illinois. Nilsson Splice (Sweden) Sjostrom, Orjan, Stabilator AB. 18. Stone, John, Belden Concrete Products 19. Wennstrom Splice (Sweden) Corporation. 20. Pogonowski Splice (USA) Talbot, W. J. Jr., Santa Fe-Pomeroy, Inc. Thorburn, J. Q., Logistics Limited. Description of Individual Splices Trueblood, C. B., Armco Steel Corporation. Thanks are expressed to John Dane III, The purpose of this section is to pro- Gerald W. Hanafy, Charles H. McGee, vide specific information concerning Robert J. Motchkavitz, and Daniel B. Nash, each individual splice. This information students in the Tulane University Depart- includes the origin, fabrication, con- ment of Civil Engineering. The manuscript struction, and use of the splice. Each was prepared by Mrs. Donna Pickens. of the above splices was analyzed and evaluated and compared in terms of several parameters. Basic considerations PILE SPLICES included size range, field time for splic- PRESENTLY IN USE ing, approximate cost, availability, and construction usage. Introductory Remarks The evaluation based on performance Twenty pile splices are discussed in data included driving performance; this section. Though each splice has compression, tension, and flexural re- unique and distinct characteristics, the sistance; fatigue; and corrosion resis- splices investigated could be catego- tance. The evaluation was based on ac- rized generally as follows: tual experimental data obtained from 1. Welded Splices tests on specific splices. Where no test 2. Bolted Splices data was available (as was the case with 3. Mechanical Locking Splices a few splices), theoretical analyses were 4. Connector Ring Splices made. 5. Wedge Splices The tests included driving tests un- 6. Sleeve Splices der variable conditions, extractions of 7. Dowel Splices piles, and flexural and shear testing of 8, Post-Tensioned Splices the full-sized extracted piles. Drawings Those specific splices that form the of each splice are provided to show the basis of this investigation included: basic concept of the splice, but are not 1. Marier Splice (Canada) intended to describe particular engi- 2. Herkules Splice (Sweden) neering details. 3. ABB Splice (Sweden) The data used to establish the evalu- 4. NCS Splice (Japan) ation of individual splices was fur- 5. Tokyu Splice (Japan) nished, for a considerable part, by fab- 6. Raymond Cylinder Splice (USA) ricators, designers, and proponents of a 7. Bolognesi-Moretto Splice (Ar- given splice. Most of the splices were gentina) proprietary, having one or more pat- 8. Japanese Bolted Splice (Japan) ents, United States or otherwise. The 9. Brunspile Connector Ring (USA) data furnished was generally favorable. 10. Anderson Splice (USA) Data reflecting unsatisfactory per- 11. Fuentes Splice (Puerto Rico) formance was difficult to obtain. A sta- 12. Hamilton Splice (USA) tus report of the investigation was pre-

PCI Journal/September-October 1974 73 sented to the 1973 Regional Meetings cumferentially into the splice to com- of the Committee on Bridges and Struc- plete it. The male cap is a tighter fit tures of the American Association of than the driving shoe because the pins State Highway Officials, in an attempt are not to be withdrawn. to uncover any problem areas with giv- The splice was patented in 1969 by en splices, or with splices in general. Gaston Marier of Princeville, Quebec.2 Although some general comments were The time required to complete the made by the bridge engineers present, splice is minimal. Reports indicate that no specific unsatisfactory performance the Marier splice has been successfully was reported. used in Canada. Herkules Splice The Herkules splice is a mechanical PILE SPLICES splice and is shown in Fig. 2. The splice INVESTIGATED is available for hexagonal, round, or square sectional shapes. It is presently Marier Splice used for reinforced concrete piling, but The Marier splice is a mechanical can be adapted for prestressed concrete splice and is shown in Fig. 1. Small piling as well. The manufacturers de- flexible pins are inserted circumferen- sign the spliced Herkules pile to devel- tially into the splice, locking the sec- op the same flexural capacity as that of tions together. Small tolerances must be the unspliced pile, and report that joint met in the fabrication of this splice as strength in compression and tension is exact fits of the locking pins are neces- designed to withstand all conditions of sary for good performance of the splice. hard or soft driving. The Marier splice requires anticipa- The Herkules splice requires prior tion in the preparation of the pile sec- preparation of the concrete piling. Steel tions. Male and female steel caps are male and female caps are cast into the cast into the ends of the piles. Holes in ends of the piles. The female cap is the caps allow prestressing strands to driven down with the bottom pile sec- pretension the piles. The prestressing tion. A special driving shoe is required strands are not mechanically connected to prevent damage to the female cap. to the pile caps. The cap is secured to The top pile section, with the male end the piling by use of dowel bars. The attached to it, is then stabbed into the number and length of dowels required female cap. to anchor the cap to the pile is depen- As shown in Fig. 2, the male cap has dent on the size of the pile and the a steel pin which protrudes at the tip. structural capacity of the pile section. This pin acts as a stabbing guide and The steel caps are circular in shape; aids in the alignment of the male and the piles need not be circular. The female caps during splicing operations. Marier splice has been successfully used The top section is rotated, locking the with octagonal piles. piles together mechanically. Two lock- The female section is driven in the ing pins are inserted into the splice, field with the use of a driving shoe. The maintaining the locked position. The shoe fits in the female end and is locked field time required to complete the to the bottom section with a locking splice is minimal and the procedure pin. When driving is completed, the simple. driving shoe is removed by pulling the The Herkules splice is manufactured locking pin from the bottom splice cap. by A. B. Scanpile, Gothenberg, Sweden. The top section is then set into position. The splice is patented and may be used Four flexible locking pins are driven cir- apart from the Herkules pile. A. B.

74 Scanpile reports 30 million ft of Her- 4. The splice is manufactured in con- kules piles have been used with the junction with the NCS prestressed con- Herkules splice over the past 10 years .3 crete piles. These piles are prestressed by the pretensioning method. The pre- ABB Splice stressing strands are tensioned; then the The ABB splice, shown in Fig. 3, is a piles are centrifugally spun. mechanical splice. It is used primarily The NCS splice consists of two steel for square piling but may also be used caps cast into the ends of the sections with round, hexagonal, octagonal, or to be spliced. The caps are connected hollow cross sections. The ABB splice to the pile tips in two ways. First, the is used on conventionally reinforced pil- caps have dowel bars attached to an- ing, but it can be adapted to prestressed chor the cap to the pile. The number concrete piles. and length of the dowels is a function The upper and lower pile sections are of the pile dimension and strength. Sec- identical. The splice consists of lock- ondly, the prestressing strands are me- blocks welded to the reinforcing rods chanically fastened to the steel cap by and cast with the piles. Reports indicate use of a buttonhead. The buttonhead that the reinforcing rods are not weak- can be seen in Fig. 4 at the tip of the ened by the weld, and the joint is at pile section. This procedure is unique least as strong as the reinforcement. in that the full prestress of the pile is The block is coated with a corrosive carried into the end of the pile section. protective material to insure long life of The bottom section is driven down, the pile. and the top section is properly aligned A special driving shoe is required to on it. The sections are then welded to- protect the protruding joint block dur- gether with a groove weld. Nippon ing driving. The top section is aligned Concrete Systems has developed three properly and lowered into the bottom methods of welding the joint: (1) hand pile section. The splice is completed by operated, (2) semi-automatic, or (3) full- driving special locking pins into the automatic joint welding. Corrosion is joint blocks, which remain in place. accounted for by increasing the size of When in position, the locking pins ex- the groove weld. ert stresses in the joint blocks which The Nippon Concrete Industries re- draw together the ends of the pile sec- ports excellent performance of the tions. The face of the splice is pre- splice. 5 The company has constructed a stressed to some extent. The time re- plant in Everett, Washington, for the quired to complete the splice is mini- manufacture of the NCS piles and mal, and the procedure is simple. splices. Acceptance and usage of the The ABB splice is manufactured and NCS splice is anticipated in the Pacific patented by the Stabilator firm of Swe- Northwest. den.4 According to reports, the ABB and Herkules splices cover the need of Tokyu Splice pile joints on the Scandinavian and The Tokyu splice is a welded splice Western European markets. Stabilator used in conjunction with piles pre- reports the strength and rigidity of their stressed with steel bars instead of joint is equal to that of a continuous strands. Seventy percent of the bars are pile. low carbon steel hardened by high fre- quency electricity; the remaining 30 NCS Splice percent are high carbon steel bars hard- The Nippon Concrete Systems (NCS) ened by drawing. This splice is shown splice is a welded splice shown in Fig. in Fig. 5.

PCI Journal/September-October 1974 75 The splice itself consists of male and strands through the cast holes in the pil- female steel caps cast into the piles. The ing and the steel splice cap. The strands male and female caps are fitted through are stretched and grouted to apply the the prestressing bars. These bars are prestress to the pile. The prestressing threaded at the ends, enabling bolts to cables are not intended to anchor the fasten the cap to the end of the pile se- cap to the pile. curely. The tightening of the bolts is, in In the field, the bottom section is effect, carrying the prestressing to the driven with the aid of a special driving tips of the pile, similar to the NCS shoe. The shoe fits over the splice cap splice. The male cap has stabilizing and is tack welded to allow driving of guides to help align the two sections the bottom section without damage to during construction. the splice. After the bottom section is The bottom section is driven in the driven, the driving shoe is removed and field with the aid of a special driving the two sections are then butt-welded shoe to protect the splice. The top sec- together. If stability problems exist, tion is stabbed into the bottom section leads are used to aid the alignment pro- and positioned. Fig. 5 shows how the cedures. Tests of the splice indicate to- stabbing guides are helpful during stab- tal time required to complete the splice bing and alignment of the sections. The to be 11/z hours. splice is completed by butt welding the The cast steel driving splice was de- pieces together. signed by Walter E. Blessey for Ray- The Tokyu welded splice is manufac- mond Concrete Pile Co., with Shell Oil tured and patented by the Tokyu Con- Company as cosponsor. As a result of crete Industry Co., of Tokyo, Japan, tests performed at Tulane University, and it is used in conjunction with their the dowel bars were lengthened from prestressed concrete piles. The splice 18 to 36 in. can be used on various sizes of cylinder piles. It is reported that the Tokyu Bolognesi-Moretto Splice splice develops the full bending The Bolognesi-Moretto splice is a strength of the unspliced section s Tests welded splice illustrated in Fig. 7. It is reported indicate that the temperatures presently used in the splicing of rein- reached during the welding of the forced concrete piles and is included in splice are not detrimental to the con- the investigation because of its adapta- crete or the prestressing bars. bility to prestressed piles. Raymond Cylinder Pile Splice The lower pile section is cast with a The Raymond cylinder pile splice is 1 -in, plate anchored to the pile tip by a welded splice, as shown in Fig. 6. The means of dowels. Four steel angles are inability to handle long sections of pre- welded to the plate and extended in stressed cylinder piling on land in- varying lengths into the pile. The splice duced development of this splice. is unique in that the dowels are angles The cylinder pile splice consists of rather than bars. two steel ring caps which are cast into The top pile section is cast in much the ends of the spun concrete piles. The the same manner; however, the base steel caps are connected directly to the plate in the top section is somewhat piling by use of dowel bars threaded smaller in size than the bottom plate. into the cap. The cap is designed with This enables the two plates to be weld- openings to allow the post-tensioning of ed together by a fillet weld. Fig. 7 the pile. shows the alignment of the plates and The post-tensioning is performed by the fillet weld required to make the the threading of the prestressing splice.

76 The bottom section is driven down to the two sections together in preparation a splicing position. The top section is set for additional driving. Reports indicate on the bottom plate and aligned. The that the tightening of the bolts pre- two plates are then welded together stresses the face of the splice to some with a fillet weld. An epoxy cover pro- extent.9 tection is spread over the weld and The bolted splice is made in Japan splice area. This is done to protect the and can be used for various sizes of splice from corrosion. Driving is then piling. Nippon Concrete Industries, Co., resumed. Ltd., produces the bolted splice in con- Bolognesi-Moretto Consulting Engi- junction with its precast reinforced con- neers of Buenos Aires, Argentina, de- crete piles. Consideration should be giv- signed and patented the splice. Reports en to corrosive effects, since the steel in indicate the the splice can be completed the splice is exposed. within 30 to 40 minutes.8 Drawings il- lustrate the splice used for 15-in. square Brunspile Connector Ring reinforced concrete piles. Test data as The Brunspile connector ring is a to the performance of this splice were wedge splice used to join prestressed not available at the time of this report. concrete piles. 10 Prior preparation of the Brunspile consists of casting a round Japanese Bolted Splice steel ferrule at the end of the pile. Small The Japanese bolted splice is shown tolerances must be met in the fabrica- in Fig. 8. It is presently used in the tion of the connector ring. A good fit of splicing of reinforced concrete piling. the ring to the steel ferrules is necessary It is included in this study because of for the proper performance of the its adaptability to prestressed concrete splice. piling. The principle of the bolted splice The Brunspile connector ring acts as is simple, but the details are relatively a wedging sleeve, as shown in Fig. 9. In elaborate. the field, the bottom pile section is driv- Preparations for the bolted splice in- en down, leaving the steel ferrule ex- volve the casting of two steel pieces into posed. The wedge connector is then the ends of the piling. Both pieces are tapped onto the steel ferrule. A 1-in. fastened to the ten reinforcing bars of impact plate is placed between the pile the piling. The bottom splice piece also sections within the connector ring. The has ten dowel bars attached which top pile section is guided into the seat- serve as additional anchorage for the ed connector ring. At this point, driving splice. The upper splice section has is begun. Initial blows of the pile driver eight dowel bars which provide addi- wedge the sections together, complet- tional anchorage to the pile section. ing the splice. Eight bolts, which are extensions of The Brunspile connector ring is dis- the eight dowel bars, protrude from the tributed by the Associated Pile and Fit- splice section. ting Corporation and Belden Concrete The field work involves the driving of Products Co., Inc. Both the Brunspile the bottom pile section in place. Tests and the Brunspile connector ring are performed on this splice emphasize the covered by United States patents. The care necessary in choosing a cushion connector ring has been used extensive- material and in driving the pile sections. ly and satisfactorily by Associated Pile The top pile is guided into place over and Fitting Corporation with steel pipe the lower section. The eight bolts act piles. Its use has not been as extensive as stabbing guides during splicing. The with prestressed concrete piles. The eight bolts are then fastened, locking connector ring was not designed as a

PCI Journal/September-October 1974 77 tension splice for prestressed concrete to splice 10-in. diameter reinforced con- piles. crete piles. Modifications in the splice could enable the Fuentes splice to be Anderson Splice used on prestressed concrete piles. The Anderson splice is a sleeve splice The Fuentes sleeve splice does re- developed for prestressed concrete quire prior preparation of the concrete piles. The steel sleeve is made to fit piles. A steel band is first welded to the tightly around the pile, as shown in Fig. pile reinforcement. The weld is made 10. Fabrication requires small toleranc- 18-in, from the splice on both the bot- es to assure the tight fit of the sleeve on tom and top pile sections. The amount the piles. The friction between the piles of welding required to connect the band and the sleeve is required for proper to the pile reinforcement is dependent alignment and performance of the pil- on the tensile forces expected in the ing. It can be fabricated for various pile. sizes and shapes of piling, with the The steel band is cast with the pile, thickness of the sleeve as a function of exposing its outer surface. A thin steel the diameter of the pile. The pile itself sleeve is then placed on the bottom sec- requires no special preparation for splic- tion and welded to the steel band. This ing. completes the prior preparation neces- The installation of this splice in the sary in the splice. field is simple. First, the steel sleeve is The bottom pile section is driven driven over the head of the bottom pile. with a special mandrel. This mandrel A plywood pad, cut to the shape of the protects the sleeve section that is to re- piling, is placed between the bottom ceive the male end of the next pile sec- and top pile sections. This acts as a tion. The top pile is inserted into the cushion during driving. sleeve, and the sleeve is welded to the The top pile is driven into the sleeve top pile. The only work required in the with a tight fit. If this is not possible, field to make the splice is the welding two halves of the sleeve may be weld- of the sleeve to the top pile section. ed together over the pile. If the splice Driving is then resumed. must develop tension, it is reported that The Fuentes sleeve splice is used in epoxy resin can be injected into the conjunction with the Fuentes Concrete space between the piles and the splice Pile. It was developed by Gabriel Fuen- sleeve. The friction between the piles tes, Jr., of Puerto Rico. 12 The pile and and the sleeve is not enough to develop splice are patented in the United States significant tensile forces. and abroad. Shorter pile sections can be The Anderson sleeve splice was de- handled more easily and do not require veloped by Dr. A. R. Anderson of Ta- large pile driving rigs. coma, Washington. It has been used by state agencies and various architects Hamilton Form Company Splice and engineers in the state of Hawaii. The Hamilton Form Company splice, Approximately 120,000 ft of prestressed shown in Fig. 12, is a sleeve splice. It concrete piles have been driven on state was designed specifically for 36-in, out- and private projects in Hawaii in the side diameter cylinder piles with 4-in. last 5 years with the use of the Ander- thick walls. son sleeve splice." Unlike most other splices, no prior preparation of the piles is necessary. Fuentes Splice The splice consists of two semi-circular The Fuentes splice is a sleeve splice, sleeve sections 8 ft in length. Small steel as shown in Fig. 11. It is presently used extensions are secured to the sleeves by

78 the welding of gusset plates. These ex- holes may be cast with the pile or tensions are used to receive the bolts drilled in the field if necessary. The top which clamp the semi-circular sections section is cast with the dowel bars in together. This arrangement is shown the end of the pile, as shown in the fig- clearly in Fig. 12. ure. The number and length of dowel In the field, the lower pile section is bars is dependent on the pile size and driven in a normal procedure. The top structural capacity. section is lowered into position and then The bottom section is driven with no properly aligned. The sleeve sections special consideration. The top section, are positioned around the joint. Bolts with the dowels protruding from the are threaded through the holes and are end, is guided and set in position over tightened with torque wrenches. Time the bottom section. The dowels act as required to complete the splice is one stabbing guides. Once in position, a thin hour to ninety minutes. sheet metal form is placed around the The Hamilton Form Company of splice. The cementing material is then Fort Worth, Texas, designed the splice poured, filling the holes of the bottom for the piles of the McBride Bridge in section and the small space between the British Columbia, Canada. The original piles. The form can be removed after design called for a 1/4-in, thick sleeve, 15 minutes and driving resumed. but this was increased to 3/s in. at the The splice is not patented. It has request of the British Columbia Depart- been used in New York14 and Florida.15 ment of Highways. The piles were driven in —30 F temperatures. Macalloy Splice Reports point out the fact that the The Macalloy splice is a post-ten- pile withstood an axial pull of 550 kips sioned splice,ls applied to prestressed and was tested in flexure until visible and reinforced concrete piling. Macal- cracking of the pile occurred. 13 A pat- loy prestressing bars are coupled con- ent was never applied for, so the splice tinuously across the joint, fully pre- is public domain. stressing it. Preparation is extensive. The lower Cement-Dowel Splice section is cast with 1 1/z-in. grouting The cement-dowel splice is shown in ducts to contain the Macalloy bars and Fig. 13. A variation of this splice is the with holes at the pile ends to receive epoxy-dowel splice. The concept of the the dowels from the top section. The splice is simple. The choice of materials bars are anchored to the bottom section used to anchor the dowels to the pilings by a sleeve at the ends of the bars, and is of prime importance. Some materials they extend out from the top of the pile. are effective in anchoring the dowels, The top section is cast with 1%-in. but require an excessive setting time, grouting ducts and high-tensile strength therein disrupting driving. Other ma- dowels. Macalloy bars are then thread- terials set quickly but are ineffective in ed through these ducts. Details of the anchoring the dowels or withstanding splice are shown in Fig. 14. driving forces. A special driving helmet is needed to The cement-dowel splice in this in- protect the protruding Macalloy bars in vestigation was made using Florok Plas- the bottom section. After driving the ticized Cement, manufactured by the bottom section, the top section is posi- Chargar Corporation of Hamden, Con- tioned over the bottom; and threaded necticut. Macalloy bars are then screwed into The bottom section of the splice has mechanical couplers. A jointing com- holes which receive the dowels. These pound is spread over the head of the

PCI Journal/September-October 1974 79 bottom pile and into the holes which and the splice is complete. Field time receive the dowels, taking care to keep required to complete the splice is mini- the grouting ducts clear. The top sec- mal and the procedure is simple. tion is lowered and seated. The Mouton splice was developed by The Macalloy bars are stressed with William J. Mouton, Jr., and patented in hydraulic jacks, post-tensioning the pil- 1972.18 It may be employed with vari- ing. The bars are wedged and driving ous shapes of piling and is presently resumed. Top sections of 40 ft and piles used in conjunction with the Tri-Pile, a up to 185 ft in length have been suc- triangular prestressed concrete pile cessfully installed with this splice. which is patented. The Macalloy splice is patented and is used in Great Britain.17 The structur- Raymond Wedge Splice al capacities of the spliced section are The Raymond wedge splice is a com- virtually the same as those of an un- bination sleeve and wedge splice. It is spliced section. Tests of the Macalloy illustrated in Fig. 16. The splice is simi- splice indicate that this method of splic- lar to a "mortise and tenon" splice19 and ing is practical. is used with prestressed concrete piles. Preparation of the piles for this splice Mouton Splice is necessary. The end of the bottom pile The Mouton splice is a combination section is cast with a pipe sleeve. The splice. It is illustrated in Fig. 15. It is top section is also cast with a pipe completed by wedging a pin connector sleeve, but this sleeve is constructed dif- into connector sleeves which are cast ferently. A portion of the sleeve is im- into the ends of the pile sections. The bedded in the tip of the pile, while the pin connector is mechanically wedged end of the sleeve is not filled with con- into position when the splice is made. crete. This sleeve has square holes cut The connector sleeve is cast into the out for the insertion of the steel wedges end of the pile along with a cast iron during splicing. Fig. 16 shows the con- head. A %-in, layer of insulation ma- struction of the pile tips clearly. terial surrounds the connector sleeve. The lower section is driven into po- This allows the pin to expand and sition for the splice to be made. The wedge itself into position without crush- top pile section is lifted into position. ing the concrete surrounding the sleeve. The pipe sleeve of the top section is Reports indicate that the fabrication lowered over the smaller pipe sleeve of and casting of the connector sleeves is the bottom section. After proper align- critical for proper performance of the ment, steel wedges are driven through splice. the holes of the outer sleeve. This pro- In the field, the bottom section is duces a tight fit between the pipe driven down and the top section set into sleeves. Once in position, the wedges position over the driven pile. The pin are welded in place to prevent move- connector is placed within the connec- ment during driving. tor sleeves of the pile sections. The top This splice was developed and pa- pile is then rotated for proper align- tented by Raymond International, Inc., ment with the bottom section. As the which has used the splice with 16%-in. top section is lowered onto the lower octagonal prestressed piles. 20 This section, the wedges in the tips of the splice can be adapted for use with other pin connector are activated and expand sizes and shapes of prestressed concrete transversely. The wedging action is piles. Prestressed concrete piles 175 ft complete when the sections are touch- long were successfully spliced in Seat- ing. The pin connector is now wedged, tle, Washington, using this splice.

80 Pile Coupler Splice ized in the cost of production of the fit- The Pile Coupler Splice shown in tings. Fig. 17 was developed and tested in The portions of the fitting which ac- 1974, and consists of a steel split ring complish the interlocking are provided connector which is used to join two with undercut edges which engage each lengths of prestressed concrete piling. other by means of a sliding ability. Prior preparation of the Pile Coupler The jointing plates are provided with Splice includes the casting and anchor- recesses which, in interlocked position, ing of steel plates into the ends of the are so located that they face each other sections to be connected. Studs are used for the purpose of forming a channel to anchor the splice plates. into which a locking bar is placed to The tension band split ring connector lock the two sections together. can be in one piece, or it can be fabri- The Nilsson Splice is capable of de- cated in two pieces. The connecting veloping the strength of the prestressed band is C-shaped and fits into grooves concrete pile, provided that it is prop- in the steel plates. A good fit of the con- erly anchored to the pile section by necting band to the steel plates is nec- means of the steel sleeve shown in the essary for the proper performance of figure. The field time required to make the splice. the splice is approximately 20 minutes. In the field, the bottom pile section The splice is shown for circular piles, is driven, leaving the steel plate ex- but can be adapted for piles of other posed. The top pile section is guided cross section configurations. onto the bottom section by a dowel, and the connecting band is fitted to the bot- Wennstrom Splice tom and top pile sections. The connec- The Wennstrom Splice is a wedge tor band is then closed with a double splice which was invented by Elof Al- beveled weld. got Wennstrom of Orebro, Sweden, and The Pile Coupler Splice was devel- is schematically illustrated in Fig. 19. oped and tested by Marine Concrete Opposing steel plates are anchored Structures, Inc.; and a United States into the pile section to be spliced. These patent has been applied for. Tests indi- steel plates are provided with register- cate that the splice, if properly an- ing grooves which extend inwardly chored, is effective in developing the from the edges of the steel plate mem- strength of the prestressed concrete bers and are of dovetailed cross section. pile. The grooves are designed to accomo- date the locking wedges shown, which are of double dovetail configuration in Nilsson Splice cross section. At their inner ends, the The Nilsson Splice was developed wedges have projections which cooper- and patented by Jan Nilsson and Sten ate with curved recesses at the inner Nilsson, and is illustrated schematically ends of the grooves. As a result, the in Fig. 18. It consists of two steel plates wedges when driven into the grooves which are mutually similar and comple- will be reliably anchored to the plate- mentary to each other in such a manner shaped members. that each one of the plates can be fitted It is reported that the driven wedges and engaged to the corresponding plate are so anchored that there is no possi- on the end of the other pile section. bility of the wedges coming loose and Since the two fittings forming the joint sliding out. are mutually alike, the jointing work is The analysis of this splice indicates simplified, and economies can be real- that it is effective in developing the

PCI Journal/September-October 1974 81 strength of the prestressed pile, if the Each splice in this report was ana- splice plates are properly anchored. The lyzed to determine its structural capac- time required to make the splice is ap- ity as compared to that of the unspliced proximately 20 minutes. pile. The piles are evaluated as structural members, even though the piles are Pogonowski Splice just one part of a soil-structure interac- The Pogonowski Splice illustrated in tion. Capacities of pile-supported struc- Fig. 20 was invented by No C. Pogo- tures are often governed by soil condi- nowski, Paul D. Carmichael, and Ed- tions, and not by the structural capaci- ward E. Bodor. The patent assigns the ties of the piles. splice to Texaco Inc. The comparative strengths of the This mechanical locking splice was spliced and unspliced sections were designed to be particularly adapted for measured in terms of compression, ten- use in offshore or similar applications, sion, and flexure. The efficiency of any where a hostile environment or a se- particular splice was computed to be vere corrosion problem is a pertinent the strength of the spliced section com- factor. The pile comprises an elongated pared to the strength of the unspliced member formed essentially of a series section; and is represented as a per- of concrete pile sections. centage. The strength of the spliced A metallic cap carried at each pile section was considered to be the section end is adapted to engage and be strength of the splice in compression, fixed to a corresponding cap on the next or in tension, or in flexure. The strength succeeding pile end thus forming a rig- of the unspliced section was considered id connection between the two sections. to be the strength of the section in com- The metal joint thus formed between pression, or in tension; or the strength the concrete sections is then isolated at which flexural cracking occurred. from its surroundings by means of an Piles are usually designed to prevent enclosing barrier formed on the pile to undesirable cracking. Those splice sys- protect the joint from corrosion. tems, in which cracking of the fully prestressed pile sections occurred before The splice is especially applicable to distress in the splice, were considered prestressed concrete cylinder piles. to be 100 percent effective in developing the cracking load for the spliced pile. ANALYSIS OF SPLICES Individual costs of the splices are not dealt with directly in this report, but in- There is a variation of the behavior formation supplied by this investigation of the various splices under field con- will give some indication as to the rela- ditions. Some may fail directly in the tive costs involved. Knowledge of the joint, while in other cases failure results preparation of piles, the availability of from bond failure of the dowels anchor- the piles, field time required for the ing the splice to the piles. Lack of abil- splice, and fabrication of the splice are ity to anchor and develop the dowels all beneficial in determining costs. A de- causes the latter problem. In some in- tailed account of the actual costs in- stances, failure occurs completely out- curred in the utilization of each splice side of the spliced region. Splice sys- was beyond the scope of this investiga- tems that develop strengths greater tion. than the piles themselves are usually costly. (Text continued on p. 93)

82 U n n u I u II ^^ II II II u II II II II II II

tr — II —^ II II II II II II II II cC

I II II II II ii II II II II c0 II II II II II II I.a II II II AI II II II ^^ II it II II U u U

SOURCE OF INFORMATION

GASTON MARIER P.O. BOX 549 PRINCEVILLE QUEBEC, CANADA

00 W FIG. I MARIER SPLICE 00

ri _ U a^°srr

^kEr{kz

rr.

?sy

3i II

it _.... rr II

SOURCE OF INFORMATION SOURCE OF INFORMATION STABILAIOR AB NIPPON CONCRETE INDUSTRIES CO., LTD. BOX 46 SUMITOMO SHINBASHI BUILDING BROMMA 1 8-3 SHINBASHI 1-CHOME SWEDEN MINATO-KU, TOKYO, JAPAN

FIG. 3 ABB SPLICE FIG. 4 NCS SPLICE ti

0 O

SOURCE OF INFORMATION SOURCE OF INFORMATION

TOKYO CONCRETE INDUSTRY CO. LTD. WALTER S. BLESSPY TANSIKE - TOKYO BUILDING TULA.NH UNIVERSITY NO. 1-1-14, AKASAKA, NIil ORLLANS DIINATO-KU, TOKYO, JAPAN LOUISIANA

C I FIG. S TOKYU SPLICI I FIG. G RAY IONll CYLINDER PILH SPLICE 00 0

SOURCE OF INFORMATION SOURCE OF INFORMATION

BOLOGNESI-MORETTO NIPPON CONCRETE INDUSTRIES CO., LTD. LUIS SAENZ PENA 250 SUMITOMO SHINBASHI BUILDING BUENOS AIRES 8-3 SHINBASHI 1-CHOME ARGENTINA MINATO-KU, TOKYO, JAPAN

FIG. 7 BOLOGNESI-MORETTO SPLICE O ti ! ;: C F

l I

III

SOURCE OF INFORMATION BELDEN CONCRETE PRODUCTS, INC. P.O. BOX 607 METAIRIE LOUISIANA

00 I FIG. 9 BRUNSPILE CONNECTOR RING 00 Co

SOURCE OF INFORMATION

HAMILTON FORM COMPANY, INC. P.O. BOX 13466 FORT WORTH TEXAS

FIG. 12 HAMILTON FORM COMPANY SPLICE c)b ti I

SOIJRCE OF INFORMATION SOURCEOF INFORMATION THE CONCRETE SOCIETY SOUTHERN BLOCK F PIPE CORPORATION CORPORATION TERMINAL HOUSE P.O. BOX 1778 GROSVENOR GARDENS NORFOLK LONDON, ENGLAND Ij VIRGINIA

c I FIG. 13 CEMENT-DOWEL SPLICE I PIG. 14 MACALLOY SPLICE II II I II II II II II 11 II 11 II I I ^ II II I i II II I I II II I I II I I II II I II II I II II I i II II_ I I II

I^I A I I II II 1 I II II I I II II I I II II I I II II I I A I 1 II r i r,n 1 e^In II" II SOURCE OF INFORMATION II a II SOURCE OF INFORMATION

II^1 WILLIAM J. MOUTON, JR. RAYMOND INTERNATIONAL INC. ,IY ° `I 2113 CLEARY AVENUE P.O. BOX 22718 If II \ METAIRIE HOUSTON LOUISIANA TEXAS

FIG. 15 MOUTON SPLICE FIG. 16 RAYMOND WEDGE SPLICE u n n II II II II I! II II II II II_ R fT fT Ef II II II II T I! !I II II II II II I! II II1I III! II II II tt tt II II II II li II II II II li tl II II

II II

ES I II II II II II II ^^ I u n n II Il 11 ES II II II n II II II II II II II I! II n N n! I I I n II II - II II II II I! II II II II II II u u u

SOURCE OF INFO RMATION SOURCE OF INFORMATION

MARINE CONCRETE STRUCTURES, INC. STEN B. NILSSON P.O. BOX 607 1 BRITTSOMMARGATAN METAIRIL CUTEBORG LOUISIANA SWEDEN

PILE COUPLER SPLICE I-N FIG. 17 FIG. 18 NILSSON SPLICE to

SOURCE OF INFORMATION SOURCE OF INFORMATION

BLOT A. WENNSTROM IVO C. POGONOWSKI OREBRO HOUSTON SWEDEN TEXAS

FIG. 19 WENNSTROM SPLICE FIG. 20 POGONOWSKI SPLICE SUMMARY OF CONCLUSIONS AND SPLICES RECOMMENDATIONS

Table 1 contains information on each Marier Splice splice. The sources of the information Care and precision in the fabrication are varied. Most of the data was gath- of the male and female caps and the ered from general correspondence with locking pins are necessary for proper the manufacturer or designer of the performance of the splice. Any slight splice. Data on the strength of the variation in the tolerances may result splices was obtained in three ways: in the failure of the splice. The use of from tests conducted during this inves- the splice must be anticipated so the caps may be cast with the piles. tigation; from experience and tests conducted by others; and from theoretical and analytical studies. Herkules Splice This has been found to be an effec- Information gathered on the splices tive method of splicing reinforced con- studied during this investigation was for crete piles. It is felt that only minor the most part favorable. There was lit- modifications would be necessary to tle difficulty in obtaining favorable re- adapt the Herkules splice to prestressed sults. Unfavorable results, however, concrete piles. Anticipation of the use were not as readily available and were of this splice is necessary because the difficult to obtain. male and female caps cannot be in- With reference to those splices listed stalled in the field. in Table 1, all are patented with three exceptions. Those splices not patented ABB Splice include the: The ABB splice can be used with various shapes of piles. It can be adapt- —Anderson Splice ed to prestressed concrete piles. The —Hamilton Form Splice steel caps cast in the ends of the pile —Cement Dowel Splice sections are symmetrical, thus eliminat- Prior preparation is required for all ing any confusion in identifying the sec- splices with two exceptions. Those tions. Extensive use of the splice in splices not requiring advance prepara- Western Europe is an indication of this tion of the pile sections include the An- effective splicing technique. derson Splice and Hamilton Form Splice. Other data is as tabulated. NCS Splice It is of importance to note that the Analysis and extensive tests of this strengths indicated for individual splic- splice point out the excellent perfor- es are dependent on close control and mance of the splice. The buttonhead process is important in carrying the full proper procedures in making the splice. prestress into the splice region. The Careless workmanship or improper field construction of a plant in Everett, procedures can result in significant de- Washington, should make the NCS pile viations from the strength levels indi- and splice a competitive one in the Pa- cated. cific Northwest. Modern welding tech- niques reduce the time normally required by hand welding.

PCI Journal/September-October 1974 93 TABLE 1. SUMMARY OF SPLICES

Strength Approximate Approximate Name of Splice Type Origin Size Range, Field Time, Percent Percent Percent in. (cm) min. Compressive Tensile Flexural Cracking

Marier Mechanical Canada 10-13 (25-33) 30 100 100 100 Herkules Mechanical Sweden 10-20 (25-51) 20 100 10000 100 ABB Mechanical Sweden 10-12 (25-30) 20 100 100 100 NCS Welded Japan 12-47 (30-119) 60 100 100 100 Tokyu Welded Japan 12-47 (30-119) 60 100 100 100 Raymond Cylinder Welded USA 36-54 (91-137) 90 100 100 100 Bolognesi-Moretto Welded Argentina Varied 60 100 55 100 Japanese Bolted Bolted Japan Varied 30 100 90 90 Brunsplice Connector ring USA 12-14 (30-36) 20 100 20 50 Anderson Sleeve USA Varied 20 100 0 100 Fuentes Welded sleeve Puerto Rico 10-12 (25-30) 30 100 100 100 Hamilton Form Sleeve USA Varied 90 100 75 100 Cement Dowel Dowel USA Varied 45 100 40 65 Macalloy Post-tensioned England Varied 120 100 100 100

Mouton Combination USA 10-14 (25-36) 20 100 40 100 Raymond Wedge Welded wedge USA Varied 40 100 100 100 Thorburn — Scotland No information available on this splice Pile Coupler Connector ring USA 12-54 (30-137) 20 100 100 100 Nilsson Mechanical Sweden Varied 20 100 100 100 Wennstrom Wedge Sweden Varied 20 100 100 100 Pogonowski Mechanical USA Varied 20 100 100 100

and based on data furnished by proponent Calculated Observed Tokyu Splice in the piles. It is felt that the high level of field control necessary for the effec- Tests performed in Japan indicate tive performance of this splice is not that the Tokyu splice is effective in splicing prestressed concrete cylinder easily obtained. piles. Temperatures due to welding do not heat the concrete as greatly as the Anderson Splice NCS splice. It is significant that pre- One advantage of the Anderson stressing bars rather than strands are splice is that no preparation of the piles used with the splice because some test is necessary prior to splicing. Waste of failures have occurred where these bars splice sections cast with piles is elimi- were threaded at the tips of the bars at nated. Piles may be extended easily the splice cap. when splicing was not anticipated. The splice can be constructed to fit a variety Raymond Cylinder Pile Splice of pile shapes and sizes. The weakness of the splice is in the tensile capacity of This pile splice was effective in splic- the connection. Extra steps must be taking cylinder piles, but not to the same en to develop significant tensile re- extent as the NCS or Tokyu splices. Ex- sistance in the pile. The splice is not tensive preparations were necessary to patented. splice the piles. A driving shoe was tack welded to the bottom section, increasing the splicing time somewhat. The Fuentes Splice weakness of the splice was in the dow- This splice has been used successfully els and not in the weld. in Puerto Rico for splicing reinforced concrete piles. Present design of the splice restricts the use of the splice to Bolognesi-Moretto Splice circular piles. Adapting the splice tech- Analysis of the Bolognesi-Moretto nique to prestressed concrete piles may splice reveals one possible weakness. It require some alterations in the splice is felt that the dowels attached to the concept. Presently, the tensile capacity plates and the weld connecting the of the splice is obtained by welding the plates may cause warping of the plate splice collars to the reinforcing bars. and damage the splice. An eccentricity This would be undesirable with the use is present in the splice. Without further of prestressing strands. test data available, it is difficult to determine actual strength levels. Hamilton Form Company Splice It is felt that cost and time of fabrica- Japanese Bolted Splice tion for this splice make it impractical It is felt that this splice is susceptible for mass production. However, job con- to corrosion because of the large area siderations, such as structural perfor- of exposed steel. Some protective coat- mance and integrity, may warrant the ing should be used to insure long life of use of the Hamilton splice in some the splice and safe performance of the cases. A patent was not applied for, so splice. the use of the splice is not restricted.

Brunspile Connector Ring Macalloy Splice This splice has performed well in Though this splice develops struc- various load tests. It is felt, however, tural capacities virtually the same as that it is not a tension splice, and should those of an unspliced section, it is felt not be used where tension is expected that the Macalloy splice is time-con-

PCI Journal/September-October 1974 95 suming and expensive. Judgment on the should result. It is essential, of course, part of the engineer is necessary to de- that the locking bar remain in position termine whether the structural effec- and not become dislodged. tiveness of the splice is more importance than the cost and time aspects. Wennstrom Splice The effective performance of this Mouton Splice splice depends among other things on The fabrication and placing of the the wedges being reliably anchored to connector sleeves is critical to the per- the plate-shaped members. Proper formance of the splice because the con- alignment of the pile sections is re- nector pin is the only piece which keeps quired in order to make the splice. The the sections together. The location of wedges must be protected against de- the connector pin in the center of the terioration, corrosion, or dislodging; for piles hinders the development of the the splice would be lost without the full flexural capacity of the pile section wedges. because of the reduced lever arm. Rigid field control is necessary for the effec- Pogonowski Splice tive performance of this splice. It is felt that the complexities of this splice demand constant attention and Raymond Wedge Splice rigorous control in the field. The em- The wedges used in this splice are bedding material, introduced in a liquid necessary for the completion and per- state into the void spaces in this splice, formance of the splice. Installation of must be properly placed if effective cor- these wedges in the field is critical. The rosion control is to be accomplished, for fit of the sleeves is not as critical with the hostile environment anticipated. the use of the wedges.

Pile Coupler Splice REFERENCES The effective performance of this splice depends on a proper fit of the 1. Britt, G. B., "Rapid Extension of connecting band to the steel plates, and Reinforced and Prestressed Con- proper anchorage of the steel plates into crete Piles," Concrete (London), the prestressed concrete pile. It is de- Vol. 5, No. 1, January 1971. sirable that the finished splice be flush 2. Marier, Gaston, "Concrete Pile with the longitudinal surfaces of the Construction," U.S. Patent No. pile. It is felt that this splice can be 3,422,630, January 21, 1969. utilized effectively and economically, 3. Severensson, S., AB Scanpile, Let- but that more experience in the field is ter to Robert N. Bruce, Jr., July 6, required. 1972. 4. Stabilator AB, "The ABB Pile Joint for High Bending Strength," No. Nilsson Splice 624.155, Bromma, Sweden, June As with other splices utilizing steel 15, 1969. plates, it is imperative that the plates be 5. Research Committee for the Struc- properly anchored into the concrete for ture of Joints of Concrete Piles, effective performance of the splice. The "The Test Research on the Struc- interlocking principle requires proper ture of Joints of Precast Concrete tolerances and good field alignment, but Piles," Reference No. 1/72, Tokyo, once accomplished, an effective splice Japan, April, 1968.

96 6. Tokyu Concrete Industry Co., Ltd., Company, Inc., Letter to Robert N. "Experimental Study on Structural Bruce, Jr., August 16, 1972. Characteristics of Joint for Tokyu 14. Goldberg, Donald, Goodkind & Systems PC Pile," Tokyo, Japan, O'Dea, Inc., Letter to Robert N. 1968. Bruce, Jr., July 25, 1972. 15 Alberdi, T., State of Florida De- 7. Bruce, Robert N., Jr., "Cast Steel Driving Splice for 36-in. O.D. Cy- partment of Transportation, Letter linder Pile," Metairie, Louisiana, to Gerald Hanafy, December 1, August, 1958. 1971. 1.6 Britt, G. B., "Rapid Extension of 8. Moretto, 0., Bolognesi-Moretto Reinforced and Prestressed Con- Consulting Engineers, Letter to crete Piles," Concrete (London), Robert N. Bruce, Jr., June 8, 1973. Vol. 5, No. 1, January 1971. 9. Research Committee for the Struc- 17 Andrews, D. A., The Concrete So- ture of Joints of Concrete Piles, ciety, Letter to Robert N. Bruce, "The Test Research on the Struc- Jr., November 13, 1972. ture of Joints of Precast Concrete 18. Mouton, William J. Jr., "Sectional Piles," Reference No. 1/72, Tokyo, Pile and Coupling Means," U.S. Japan, April, 1968. Patent No. 3,651,653, March 28, 10. Belden Concrete Products Corpora- 1972. tion, "Brunspile," U.S. Patent No. 19. Fuller, F. M., Raymond Interna- 2,983-104, Metairie, Louisiana. tional, Inc., Letter to Gerald Hana- 11. Banks, Paul I., Hawaiian Dredging fy, November 29, 1971. and Construction Company, Letter 20 Alley, E. W., "Long Prestressed to Robert N. Bruce, Jr., July 13, Piles," Civil Engineering—ASCE, 1972. Vol. 40, No. 4, April 1970. 12. Fuentes, "Fuentes Concrete Pile," 21. ACI Committee 543, "Recommen- U.S. Patent No. 2,698,519 and dations for Design, Manufacture, others, Bayamon, Puerto Rico, and Installation of Concrete Piles," 1970. ACI Journal, Proceedings Vol. 70, 13. McCalla, W. T., Hamilton Form No. 8, August 1973.

Discussion of this paper is invited. Please forward your discussion to PCI Headquarters by February 1, 1975, to permit publication in the March-April 1975, PCI JOURNAL.

PCI Journal/September-October 1974 97