Concrete Patents (Class 405/256)
  • Patent number: 5934835
    Abstract: A solid pre-cast prestressed concrete foundation pile and associated installation components having a single prestressing strand located on the longitudinal center axis of the pile, reinforced in the ends only with helix shaped wire reinforcement. The prestressing strand extends beyond the concrete face on the end to present an attachment point for a connection device used to transmit forces from a structure foundation and to accommodate the utilization of a unique, reusable cushion block and, where necessary a, particular internal splice device to form a continuous pile composed of multiple segments.The cushion block receives hammer blows applied to the top of the pile necessary to the driving (installation) process, affording protection to the pile top, the exposed strand and the internal splice device. The completed installation may include the optional attachment of the connection device (when required) after removal of the cushion block.
    Type: Grant
    Filed: January 2, 1997
    Date of Patent: August 10, 1999
    Inventors: Stephen K. Whitty, Jr., Henry R. Whitty
  • Patent number: 5931604
    Abstract: A reduced skin friction driven pile which reduces the downward frictional force applied to the pile by the settling of compressible soils surrounding the pile after the pile is driven, comprising a pile which may include a friction reduction coating located about a portion of the exterior of the pile which is expected to have soils settling relative to it. Additionally, a friction reduction collar may be placed at a location along the pile which will create a void between the soil and the portion of the pile above the collar when the pile is driven, so that soils may settle relative to the pile with the void providing reduced contact between the settling soils and the pile so that the downward force of settling soils is reduced.
    Type: Grant
    Filed: December 2, 1997
    Date of Patent: August 3, 1999
    Assignee: Foundation Technologies, Inc.
    Inventors: Frankie A. R. Queen, Jimmy D. Sailors
  • Patent number: 5909984
    Abstract: A pile forming system and method for forming a pile. The pile forming system comprises a top pile forming member, a bottom pile forming member, and an end plate assembled together to provide a complete pile form which can then be filled with concrete to form the pile. Additionally, the pile forming system incorporates a tip forming member which can be secured to one end of the pile form to form a sharp tip at one end of the pile facilitating driving the pile into a subsurface. Additional pairs of top and bottom pile forming members may be joined end to end to form longer piles. After the desired pile form is assembled, concrete is poured or pumped into the pile form through openings on the top surface of the pile form. Preferably, reinforcement bars or rebars which are coated with a non-permeable coating to prevent rust are placed in the pile form before the pouring of the concrete.
    Type: Grant
    Filed: February 15, 1997
    Date of Patent: June 8, 1999
    Inventor: Mike R. Matthews
  • Patent number: 5826387
    Abstract: An upright cylindrical pier foundation is constructed of cementitious material. The lower end of the foundation has a plate or circumferential ring fully embedded therein and long circumferentially spaced rods or bolts have their lower ends anchored relative to the ring. The upper ends of the long rods project up outwardly of the top of the foundation. The rods are shielded over substantially their entire length against bonding with the cementitious material to allow the rods, when heavily tensioned, to stretch within the cementitious material. A heavy flange, which may comprise the base flange of a tubular tower, is positioned downwardly upon the upper end of the foundation with the upper ends of the bolts projecting through holes provided therefor in the base flange.
    Type: Grant
    Filed: December 24, 1996
    Date of Patent: October 27, 1998
    Inventors: Allan P. Henderson, Miller B. Patrick
  • Patent number: 5797705
    Abstract: A tool for making holes in the ground comprises a ram tip and coupling for connecting to a drive device, such as a hydraulically or pneumatically actuated pile driving machine, or a vibrating pile driving machine. A method for making tubular foundations in the ground comprises coupling a ram tip to a drive device, selecting a location for making a hole, placing the ram tip thereat, setting the drive device into operation to drive the ram tip into the ground to form a hole, removing the ram tip out of the hole, partially filling the hole with concrete, re-inserting the ram tip into the hole before the concrete sets, setting the drive device into operation and then removing the ram tip, thereby obtaining a tubular foundation.
    Type: Grant
    Filed: October 15, 1996
    Date of Patent: August 25, 1998
    Assignee: Willibald Kellner
    Inventor: Willibald Kellner
  • Patent number: 5788419
    Abstract: A solid pre-cast prestressed concrete foundation pile and associated installation components having a single prestressing strand located on the longitudinal center axis of the pile, reinforced in the ends only with helix shaped wire reinforcement. The prestressing strand extends beyond the concrete face on the end to present an attachment point for a connection device used to transmit forces from a structure foundation and to accommodate the utilization of a unique, reusable cushion block and, where necessary a, particular internal splice device to form a continuous pile composed of multiple segments. The cushion block receives hammer blows applied to the top of the pile necessary to the driving (installation) process, affording protection to the pile top, the exposed strand and the internal splice device. The completed installation may include the optional attachment of the connection device (when required) after removal of the cushion block.
    Type: Grant
    Filed: August 14, 1995
    Date of Patent: August 4, 1998
    Inventors: Stephen K. Whitty, Jr., Henry R. Whitty
  • Patent number: 5772363
    Abstract: A pile remover has a first embodiment for removal of short pilings and a second embodiment for long pilings. Both embodiments include a pile-fitting tube with hydraulic cylinders at the top end of the tube that push downward to cause rocking cutters at the bottom end of the tube to pivot with sharpened ends moving inward to shear off the piling. Both embodiments are designed for use with a back hoe or a derrick. After a piling has been shearing, with the cutters still in cut position, the back hoe operator can lift the cut off piling and deposit it on a barge or other conveyance by reversing the cutter action and drooping the piling.
    Type: Grant
    Filed: December 5, 1996
    Date of Patent: June 30, 1998
    Inventor: John G. Larson
  • Patent number: 5582899
    Abstract: In order to cut soft concrete before it has completely hardened, or about 12 to 18 hours after finishing, a rotating cutting blade and its drive motor are mounted on a wheeled support platform. The blade extends through a slot in the platform, and also through a skid plate depending from the platform, in order to cut the concrete below the skid plate. The slot and the skid plate are sized to support the concrete as it is being cut and to inhibit cracking and chipping of the concrete during cutting. The slot preferably has as little space as possible between the sides of the slot and the adjacent sides of the cutting blade. An extendable handle allows the device to be used beyond the physical reach of the operator.
    Type: Grant
    Filed: July 2, 1993
    Date of Patent: December 10, 1996
    Inventors: Edward Chiuminatta, Alan R. Chiuminatta
  • Patent number: 5542785
    Abstract: A spacer (20) is mounted on a lateral rebar tie (13) of a reinforcement cage (11) of a poured concrete foundation support. The spacer (20) includes a pair of interlocking wheel members (21 and 22) which lock the wheel members (21 and 22) together in a mated interlocked relationship rotatably mounted about a lateral tie (13) of the reinforcement cage (11) to form the spacer (20). As the reinforcement cage (11) is inserted into an excavated shaft, the outer side wall (32) of the spacer (20) engages and rolls along the side wall thereof. The engagement of the side wall of the excavated shaft by the spacers (20) centers the reinforcement cage within the excavated shaft and maintains the reinforcement cage in its centered position as the excavated shaft is filled with concrete.
    Type: Grant
    Filed: September 28, 1993
    Date of Patent: August 6, 1996
    Assignee: Lowtech Corporation, Inc.
    Inventor: George T. Cloud
  • Patent number: 5533835
    Abstract: A railroad crossing signal foundation has upright guide rods (19) to which an upper frame member (14) and a lower frame member (15) are mounted. A concrete reinforcement gridwork (16,17) is supported on the lower frame. After erection in a ground hole, concrete is poured into the hole to a fill plane defined by the upper frame member (14) so as to embed the frame member and gridwork and a portion of the guide rods located below the fill plane.
    Type: Grant
    Filed: February 6, 1995
    Date of Patent: July 9, 1996
    Inventor: A. M. Angelette
  • Patent number: 5429455
    Abstract: An integral combination of column and pile for use in building structures in a sandy soil. The method of formation is to provide a ground situs of suitable depth and width formed preferably by an hydraulic-powered auger. The situs is then filled with a cementitious slurry. A reinforced precast concrete column is provided having reinforcing bars extending a substantial length out of its bottom. The exposed bars are inserted into the slurry until the column merges with the slurry. Upon the hardening of the slurry, the result is an integral column and pile set into the ground.
    Type: Grant
    Filed: June 28, 1993
    Date of Patent: July 4, 1995
    Assignee: State Paving Corporation
    Inventor: Michael C. Bone
  • Patent number: 5423634
    Abstract: A hydraulic composition comprising (a) a cement composition prepared by subjecting size-adjusted cement having its particle size distribution adjusted to have a 50% pass particle diameter of from 2 to 7 .mu.m and a ratio of a 90% pass particle diameter to a 10% pass particle diameter of from 25 to 40 to a water-spraying treatment to increase the loss on ignition thereof by 0.5 to 2.0% by weight and (b) a water reducing agent; and a process for producing a concrete pile by using a mixture of the hydraulic composition and from 18 to 25% by weight of water based on the hydraulic composition. A mortar or concrete mixture of the hydraulic composition exhibits sufficient fluidity and provides a hardened product having a greatly improved compressive strength. The concrete pile produced by using the hydraulic composition has a compressive strength of 800 kgf/cm.sup.2 or higher at one day age.
    Type: Grant
    Filed: March 19, 1993
    Date of Patent: June 13, 1995
    Assignee: Nihok Cement Company, Ltd.
    Inventors: Kotaro Fujita, Kazuto Yoshimori, Tomoyuki Sugaya, Yukinori Yamazaki, Takashi Suzuki, Satoshi Tanaka, Takahisa Okamoto
  • Patent number: 5320453
    Abstract: A method of driving a sectional hollow concrete pile comprises applying a direct driving force to the upper end of a first pile section and driving it into the ground. Thereafter, a second similar pile section is applied to the top of the first driven pile section and the composite sectional pile is driven to the required depth. Further, similar sections may be applied one on top of the other and the composite pile thereby formed after the application of each further pile section is driven to the required depth.
    Type: Grant
    Filed: April 6, 1992
    Date of Patent: June 14, 1994
    Assignee: Roger Bullivant of Texas, Inc.
    Inventor: Roger A. Bullivant
  • Patent number: 5320452
    Abstract: A cast-in-place concrete pile essentially consists of a lower concrete layer having fibers intermixed therein and an upper concrete layer having reinforcing elements. The lower portions of the reinforcing elements are embedded in the lower concrete layer to increase the bonding strength between the lower and upper concrete layers. The cast-in-place concrete pile of the present invention is constructed according to the following method. That is, an excavated hole is firstly formed in the ground. The reinforcing elements are placed at the upper side of the excavated hole, and then concrete including the fibers is cast into the excavated hole until the lower portions of the reinforcing elements are embedded in thus cast concrete, so that the lower concrete layer is formed. Continuously, concrete is cast onto the lower concrete layer in the excavated hole to form the upper concrete layer.
    Type: Grant
    Filed: December 29, 1992
    Date of Patent: June 14, 1994
    Assignee: Kabushiki Kaisha Ask Kenkyusho
    Inventor: Mitsuhiro Kunito
  • Patent number: 5304015
    Abstract: A pile grabbing apparatus comprising a steel I-beam of appropriate length supporting two claw assemblies. The claw assemblies are each driven by two hydraulic cylinders to grab and hold a concrete pile. A pair of steel support plates are welded onto the I-beam and with a "quick coupler", the I-beam is attached to the arm of a mobile excavating apparatus, such as a dirt excavator. The hydraulic cylinders are connected to hydraulic hoses and controlled by a control module. The operator at the control module may manipulate the claw assemblies to open and close.
    Type: Grant
    Filed: February 17, 1993
    Date of Patent: April 19, 1994
    Inventor: Roy N. Sonomura
  • Patent number: 5234288
    Abstract: An integral combination of column and pile for use in building structures in a sandy soil. The method of formation is to provide a ground situs of suitable depth and width formed preferably by an hydraulic-powered auger. The situs is then filled with a cementitious slurry. A reinforced precast concrete column is provided having reinforcing bars extending a substantial length out of its bottom. The exposed bars are inserted into the slurry until the column merges with the slurry. Upon the hardening of the slurry, the result is an integral column and pile set into the ground.
    Type: Grant
    Filed: August 29, 1991
    Date of Patent: August 10, 1993
    Assignee: State Paving Corporation
    Inventor: Michael C. Bone
  • Patent number: 5228806
    Abstract: A gravity pile for platform foundations is described which comprises a series of pile sections made from two concentric tubes the annular space between which is filled with an elevated specific weight composition such as mortar or hematite. Individual pile sections can be joined together by means of tubular connecting rings welded to the ends of the sections and welded or screwed to each other. The uppermost section of the pile may be provided by a tubular support ring provided with a peripheral load bearing flange for simple direct contact support of the template designed to receive the tethers of the platform. A process is also described for installing the pile in which the pile penetrates the sea bed under its own weight and penetration is then complements by conventional undersea pile driving or preferably by jetting the interior of the pile using the drilling string of the rig. Further weight may be provide by adding cement to the interior of the pile using the same drilling line.
    Type: Grant
    Filed: May 17, 1991
    Date of Patent: July 20, 1993
    Assignee: Petroleo Brasileiro S.A.-Petrobras
    Inventors: Cipriano J. De Medieros, Jr., Luiz H. Hassui
  • Patent number: 5188485
    Abstract: A foundation pile of reinforced, preferably prestressed concrete having external screw threads and an interior cavity for the engagement of the driver rod applying the torque, at least two flat steel bars being fastened axially parallel in the pile wall to approximately equal angular spacing, and extending by about half of their width freely into the cavity serving for the engagement of the driver rod.
    Type: Grant
    Filed: June 18, 1991
    Date of Patent: February 23, 1993
    Assignee: Pfleiderer Verkehrstechnik GmbH
    Inventors: Richard F. Forster, Friedemann A. Rudersdorf
  • Patent number: 4919572
    Abstract: Concrete fender pile having prestressing members (19, 20) of elongated, high-strength fiber composite elements (21) with a low modulus of elasticity which, during a ramming impact (p), permit a large elastic deflection of the fender pile (14) and are insensitive to aggressive environmental effects.
    Type: Grant
    Filed: September 12, 1988
    Date of Patent: April 24, 1990
    Assignee: Strabag Bau-AG
    Inventor: Jurgen Bergfelder
  • Patent number: 4911581
    Abstract: An apparatus for screwing a concrete pile (10) into ground comprises a rotary drive (26, 40, 42) and a linear drive (46, 48) both acting on the pile. An angle indicator (58) is associated to the rotary drive (26, 40, 42) and a linear position indicator cooperates with the linear drive (46, 48). A control unit (60) receives the output signals of the angle indicator (58) and the linear position indicator (56) and provides control signals to the rotary drive (26, 40, 42) and the linear drive (42, 48) corresponding to the pitch of the helical rib (16) formed on the concrete pile (10).
    Type: Grant
    Filed: May 20, 1987
    Date of Patent: March 27, 1990
    Assignee: Delmag Maschinenfabrik Reinhold Dornfeld GmbH & Co
    Inventor: Magnus Mauch
  • Patent number: 4906141
    Abstract: The present invention concerns a method of anchoring a prefabricated pile into the ground as well as a pile for carrying out this method. The prefabricated pile (P) comprises essentially at its lower portion a recess (1) containing a bladder (2) connected to a source of material under pressure through the agency of a pile-line (3) extending along the axis of the pile, so that, when the bladder (2) is inflated, a radial deformation of the lower portion of the pile is provided to thus supply the latter with a base. The pile according to this invention is useful for any kind of works and presents an increased strength against tensile and compressive stresses.
    Type: Grant
    Filed: March 18, 1988
    Date of Patent: March 6, 1990
    Assignee: Companie Internationale des Pieux Armes Frankinoul
    Inventor: Rainer Massarsch
  • Patent number: 4900193
    Abstract: A splicing device for concrete structural members includes two mating connectors positioned in axial alignment adjacent to each other that are interlocked by a key inserted through a keyway provided in the sidewalls of the connectors. Prestressing strands in the structural members to be spliced are fastened to the connectors by inserting them into axial holes located in the ends opposite the mating ends of the connectors, and thereafter wedging the strands within frustum-shaped cavities forming part of the holes, by means of frustum-shaped segments, or feathers, forced against the elements within the cavities. Apparatus and a method for installing the splicing device is also described.
    Type: Grant
    Filed: February 16, 1989
    Date of Patent: February 13, 1990
    Assignee: The Foundation Equipment Corporation
    Inventor: Alan G. MacKinnon
  • Patent number: 4862576
    Abstract: A method for restressing and locking HHL anchor, comprising a bearing plate placed between a gripping wedge and ground, a bearing shell is mounted over and connects with a jack, a load cell and a nut in series, a jack rod is inserted within the jack and has its lower end threaded inside for engaging with the gripping wedge and then determines the tension of the strands, characterized by providing a tension rod with a lower threaded end outside engaging with the bore of gripping wedge and a upper polygonal convexity fitted with a polygonal concavity of an extension rod having a upper polygonal end and inserted within the upper portion of the jack, operating the jack and jack rod for forcing the gripping wedge upwards for restressing said tension strands, and then, while maintaining the wedge in the restressed position, using a wrench for turning the extension rod as well as the tension rod downwards until the end of the tension rod touches the surface of the bearing plate for obtaining 100% restressing of the
    Type: Grant
    Filed: August 30, 1988
    Date of Patent: September 5, 1989
    Inventor: Hsi H. Lu
  • Patent number: 4708530
    Abstract: A concrete foundation pile and a device for driving the pile into the ground. The pile is provided with an outer surface having a screw thread element extending over a considerable part thereof, and a cavity extending from an opposite end of the pile forming an internal engaging surface extending over the part of the pile over which the screw thread element extends. A rotational driving force is transferred over said internal engaging surface substantially along the full length over which the screw thread element extends.
    Type: Grant
    Filed: October 14, 1986
    Date of Patent: November 24, 1987
    Inventor: Pieter Faber
  • Patent number: 4627769
    Abstract: A concrete foundation pile has a concrete body with reinforcing bars, a steel anchorage plate, a steel capping plate and a removable reinforcing bar which is anchored to the anchorage plate and whose end is located in a recess in the cappling plate. The reinforcing bar can be releasably coupled to the bar of an aligned pile to tension the composite pile formed from a plurality of aligned piles. The capping plate takes hammer blows applied to the upper end of the pile and the upper end of the bar is protected in the recess. The reinforcement is densest immediately below the anchorage plate and steel capping plate.
    Type: Grant
    Filed: December 22, 1980
    Date of Patent: December 9, 1986
    Inventor: Paul Lee
  • Patent number: 4605340
    Abstract: A pile splice includes two splice plates, each having a dove-tail shaped groove aligned with the groove in the abutting plate. Slip cams are disposed in the channel, defined by the grooves, for outward movement to draw the plates together. Drive wedges are driven between the slip cams to drive them outwardly to draw and hold the plates together and to form a massive, strong pile splice. Wedge forces are distributed to increase clamping forces. Headed reinforcing bars are securely held in the splice plates by plastic bushings to facilitate splice plate alignment and pile casting. Methods are provided.
    Type: Grant
    Filed: March 28, 1984
    Date of Patent: August 12, 1986
    Inventor: Karl Stephan
  • Patent number: 4604003
    Abstract: A method and apparatus for retensioning the development length of strands of an elongated prestressed concrete member is provided in which the ends of the strands are exposed, a metallic plate having tapered holes therein is placed over the ends of the strands, retaining wedges are inserted into the tapered holes of the plate to grip the ends of the strands, and a predetermined amount of tension is applied to the strand and maintained in the strand by the retaining wedges. A jack is provided to apply the tension to the strand. The prestressed concrete members such as piling, may be spliced together by using the apparatus on adjoining ends of piling.
    Type: Grant
    Filed: June 27, 1985
    Date of Patent: August 5, 1986
    Inventors: Ronald A. Francoeur, Verne L. Schellhorn
  • Patent number: 4588327
    Abstract: A precast concrete pile which includes a tapered end with alternating enlarged cross-sections and contracted cross-sections through its length. The concrete pile is driven into the ground together with a soil solidifying supply pipe and a cement slurry supply pipe. The pile footing in the ground is formed with concrete formations around the contracted sections, thereby increasing the bearing capacity of the pile footing.
    Type: Grant
    Filed: February 28, 1984
    Date of Patent: May 13, 1986
    Inventor: Juei J. Lin
  • Patent number: 4543015
    Abstract: A new pile is disclosed which includes a pile shaft and wedge-forming means of castable material spaced upward of the tip of the pile shaft and proximate thereto. The wedge-forming means cooperates with the portion of the pile beneath it, during driving, to cause the formation of a wedge of soil. The thus-formed soil wedge is in contact with other soil and the resulting soil-soil interface has enhanced pile supporting characteristics.
    Type: Grant
    Filed: September 14, 1983
    Date of Patent: September 24, 1985
    Inventor: William E. Kruse
  • Patent number: 4504174
    Abstract: The present invention relates to elongated elements of concrete pre-stressed by tensioned reinforcements adherent to this concrete. Each element comprises a box capping its end to which the reinforcements are fixed and which is provided with a flange allowing tensioning of the reinforcements and the possible assembly of two elements end to end. The invention is applicable to all structures formed by elements pre-stressed by adherent reinforcements, and in particular to driven-in piles.
    Type: Grant
    Filed: January 4, 1983
    Date of Patent: March 12, 1985
    Assignee: Freyssinet International (STUP)
    Inventor: Pierre Barthel
  • Patent number: 4349298
    Abstract: A new pile is disclosed which includes a pile shaft and wedge-forming means of castable material spaced upward of the tip of the pile shaft and proximate thereto. The wedge-forming means cooperates with the portion of the pile beneath it, during driving, to cause the formation of a wedge of soil. The thus-formed soil wedge is in contact with other soil and the resulting soil-soil interface has enhanced pile supporting characteristics.
    Type: Grant
    Filed: January 24, 1980
    Date of Patent: September 14, 1982
    Inventor: William E. Kruse
  • Patent number: 4327703
    Abstract: A method of preparing the upper end of a concrete column containing elongated reinforcing elements for connection to a cast-in-place beam supported by the column. The method comprises the steps of determining the elevation at which the column is to engage the beam, severing the column a distance above said elevation, axially core drilling the column to said elevation, scoring the outside of the column at the elevation by use of an abrasive saw, crushing the shell of the column about the area previously core-drilled to fracture the concrete and free the elongated reinforcing elements, and finally bending the elongated reinforcing elements into a position in which they tie into the cast-in-place beam structure to be supported by the column.
    Type: Grant
    Filed: February 8, 1980
    Date of Patent: May 4, 1982
    Inventor: Allen L. Destree
  • Patent number: 4317643
    Abstract: This invention relates to a reinforced concrete pile having a plurality of steel reinforcing cables and at least one ferrous metal alloy electrically conductive rod per cable which permits severing by oxygen cutting or electric arc welding.
    Type: Grant
    Filed: November 14, 1979
    Date of Patent: March 2, 1982
    Inventor: Donald S. Miller
  • Patent number: 4239105
    Abstract: A multi-compartment capsule having a longitudinally extending tubular inner compartment for containing a catalyst and a longitudinally extending tubular outer compartment around the inner compartment for containing a resin composition. The longitudinally extending tubular inner and outer compartments are formed by a single-ply film strip of polyester material to which are welded along opposite longitudinal edges two-ply strips having a first ply of polyester material welded to the polyester film strip of the single-ply strip and a second ply of polyethylene material. The composite sheet made up of the single-ply strip and two-ply strips is folded upon itself along one two-ply marginal edge to form the tubular inner compartment so that the polyethylene ply material at the composite strip edge contacts such ply material when folded and is welded thereto.
    Type: Grant
    Filed: August 2, 1979
    Date of Patent: December 16, 1980
    Assignee: General Electric Company
    Inventor: Peter T. Gilbert
  • Patent number: 4239419
    Abstract: A reinforced concrete threaded pile provides a generally conically shaped tapered concrete pile member which is provided with a metallic reinforcement core for carrying the torsional and tensile forces created in the pile during its insertion. A metallic head is provided at, for example, the upper portion of the pile, which provides a point for the connection of a sufficient torsional driving force thereto for insertion of the pile. The head member can be metallic, and is substantially integrally connected to the reinforcement core, so that the torsional forces can be developed through the head and the reinforcement core such that torsional and tensile forces are not carried by the concrete to a degree which would cause a failure of the concrete by cracking. The concrete body is provided with an outer surface of spiral threads which has a relatively minor thread pitch that provides for relatively easy insertion of the pile into the desired soil medium and is mechanically compatible therewith.
    Type: Grant
    Filed: October 27, 1977
    Date of Patent: December 16, 1980
    Inventor: William F. Gillen, Jr.
  • Patent number: H402
    Abstract: A high-energy-absorbing prestressed concrete fender pile, and fendering sem using a plurality of such piles, constructed from high-strength concrete prestressed with longitudinal tensioned strands only partially prestressed such that the longitudinal strands remian elastic to provide high remaining material strength for absorbing high energy impact prior to reaching the yield strength of the strands; the longitudinal tensioned strands are wrapped with an outer spiral wire reinforcement, and the longitudinal strands are preferably stressed to remain elastic until the concrete reches a capacity of 0.003 inch/inch compression strain.
    Type: Grant
    Filed: April 23, 1987
    Date of Patent: January 5, 1988
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Robert W. Julian, Robert F. Mast, Joseph R. Schlechten, George E. Warren, Manfred H. Zinserling