US3711935A - Method for introducing a prestress to a cylindrical concrete structure - Google Patents

Method for introducing a prestress to a cylindrical concrete structure Download PDF

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Publication number
US3711935A
US3711935A US00082581A US3711935DA US3711935A US 3711935 A US3711935 A US 3711935A US 00082581 A US00082581 A US 00082581A US 3711935D A US3711935D A US 3711935DA US 3711935 A US3711935 A US 3711935A
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United States
Prior art keywords
inclined faces
wedge members
members
circumferential direction
prestress
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Expired - Lifetime
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US00082581A
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English (en)
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K Hiraga
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TAISER KENSETSU KK
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TAISER KENSETSU KK
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    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
    • E04G21/12—Mounting of reinforcing inserts; Prestressing
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04H—BUILDINGS OR LIKE STRUCTURES FOR PARTICULAR PURPOSES; SWIMMING OR SPLASH BATHS OR POOLS; MASTS; FENCING; TENTS OR CANOPIES, IN GENERAL
    • E04H7/00—Construction or assembling of bulk storage containers employing civil engineering techniques in situ or off the site
    • E04H7/02—Containers for fluids or gases; Supports therefor
    • E04H7/18—Containers for fluids or gases; Supports therefor mainly of concrete, e.g. reinforced concrete, or other stone-like material
    • E04H7/20—Prestressed constructions
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49826—Assembling or joining
    • Y10T29/49863—Assembling or joining with prestressing of part
    • Y10T29/49874—Prestressing rod, filament or strand

Definitions

  • ABSTRACT A method for introducing a prestress to a cylindrical concrete structure is disclosed, which is characterized by the steps of providing a desired number of step portions or notched portions having outer peripheral inclined faces, the thickness of which vary gradually either in the direction of generating lines of the cylinder structure or in the circumferential direction thereof, respectively.
  • the inclined faces extend either along the circumferential direction or along the direction of the generating lines on the outer I peripheral surface of the cylindrical structure.
  • Wedge members are slidably disposed on the respective inclined faces and also jacks are provided for sliding the wedge members.
  • Tensioning members are wound around the outer peripheral surfaces of the wedge members along the circumferential direction.
  • the tensioning members wound around the outer periphery of the inclined faces in the circumferential direction are tensioned by operating the jacks to cause the respective wedge members to slide along the inclined faces; whereby a prestress is introduced to the cylindrical concrete structure.
  • the present invention relates to a method for introducing a prestress to a huge cylindrical structure such as, for example, a pressured vessel of atomic piles or the like, a water tank, a water tower, etc.
  • One of the principal objects of the present invention is to provide an improved method for insuring the introduction of a desired prestress to a cylindrical concrete structure by means of a simple operation.
  • Another principal object of the present invention is to provide an improved method for introducing a desired prestress to a cylindrical concrete structure by making use of a very small jacking force.
  • Still another principal object of the present invention is to provide an improved method accompanied with little loss of tension in the tensioning members for introducing a prestress to a cylindrical concrete structure.
  • Yet another principal object of the present invention is to provide an improved method wherein the tensioning members for introducing a prestress to a cylindrical concrete structure are not apt to be subjected to a deteriorative effect due to the temperature and/or the radiation rays within said structure.
  • the method of the present invention is characterized by the steps of providing a desired number of step portions or notched portions having outer peripheral inclined faces, the thickness of which vary gradually either in the direction of generating lines or in the circumferential direction, respectively of the cylindrical structure, and which extend along either the circumferential direction on along the direction of the generating lines on the outer peripheral surface of the cylindrical structure.
  • Wedge members are slidably disposed on the respective inclined faces also jacks also are positioned for sliding the wedge members.
  • Tensioning members are wound around the outer peripheral surfaces of the wedge members along the circumferential direction. The tensioning members are stretched around the outer periphery of the inclined faces in the circumferential direction, by operating the jacks to cause the respective wedge members to slide along the inclined faces; whereby a prestress may be introduced into the cylindrical concrete structure.
  • the outer peripheral surfaces of the desired number of step portions or notched portions provided either along the circumferential direction or along the direction of generating lines on the outer periphery of the cylindrical concrete structure to which a prestress is to be introduced are formed of inclined faces, where the thickness varies gradually either in the direction of generating lines or in the circumferential direction, respectively, of said structure; and since after the tensioning members for introducing a prestress have been circularly wound around the outer peripheral surfaces of the wedge members slidably provided on the inclined faces, the wedge members are caused to slide along the inclined faces by means of the jacks.
  • the peripheral lengths of the circular tensioning members are caused to increase, resulting in stretching in the circumferential direction of the tensioning members; whereby the stretching force may be introduced as a compression prestress to the cylindrical concrete structure via the wedge members,
  • the tensioning members upon stretching tensioning members for introducing a prestress to a cylindrical concrete structure, it is only necessary to displace the wedge members on which the tensioning members are wound by means of the jacks without directly stretching the tensioning members by making use of jacks, so that a desired large prestress can be introduced into the cylindrical concrete struc ture with an extremely small jacking force, and also a large stretching force is not required in the step of winding the tensioning members around the wedge members but instead the necessary work can be carried out simply. Still further, since the tensioning members make contact only with the outer peripheral surfaces of the wedge members and are in a free state, there occurs no loss of stretching force due to frictional resistance upon stretching the tensioning members.
  • the tensioning members do not penetrate through the inside of the wall member of the cylindrical concrete structure but are positioned along the outer peripheral surface of the wall member, the arrangement of the tensioning members does not prevent the construction work for the concrete body of the structure and does not lower the efficiency of construction. Also since the strain of the tensioning members can be directly measured, the control of the tension may be carried out securely, refastening of the tensioning members may be readily achieved if necessary.
  • the tensioning members are less apt to be subjected to a deteriorative effect of its internal temperature and/or radiation rays than in the case of positioning within the wall member.
  • FIGS. 1 and 2 are perspective view, and a partial enlarged longitudinal cross-section view, respectively, of a cylindrical concrete structure to which the present invention is applicable,
  • FIG. 3 is a partial longitudinal cross-section elevation view showing a working state according to one preferred embodiment of the present invention
  • FIG. 4 is a longitudinal cross-section view showing a working state at the upper end portion of the structure
  • FIG. 5 is a longitudinal cross-section view showing a working state according to another preferred embodiment of the present invention.
  • FIGS. 6 and 7 are a transverse cross-section view showing a working state according to still another preferred embodiment of the present invention, and a perspective view of a cylindrical structure to which the same method is applicable, respectively,
  • FIG. 8 is a longitudinal cross-section view showing a working state according to yet another preferred embodiment of the present invention.
  • FIGS. 9 and 10 are longitudinal cross-section view showing a working state according to still another preferred embodiment of the present invention, and a partial perspective view of a cylindrical concrete structure to which the same method is applicable, respectively,
  • FIGS. 11 and 12 are a transverse cross-section view and a partial enlarged transverse cross-section view
  • FIG. 13 is a perspective view of a cylindrical concrete structure to which the method illustrated in FIGS. 11 and 12 is applicable.
  • FIGS. 1 and 2 illustrate a cylindrical concrete structure (A) to which the method according to the present invention is applicable.
  • a cylindrical body (1) having a thickness a and a radius r are provided on the outer peripheral surface of a cylindrical body (1) having a thickness a and a radius r.
  • the outer peripheral inclined faces (2a) of the respective steps (2) are inclined in the direction of generating lines with a gradient of desired angle with respect to the vertical surface, and the lower end faces (2b) are formed at right angles with the inclined faces (2a) of the next succeeding step portion (2).
  • the gradient angle 0 of said step portions (2) is selected depending upon the coefficient of friction of the wedge members as described later, the capability of the jacks, and the radius of said structure.
  • the length b in the direction of generating lines of each step portion (2) is selected so that it may become equal to the sum of the lengths of the jack and the wedge member along each inclined face, the stroke of the jack, and an appropriate additional length, and also so that the length c of the lower end face of the step portion (2) may become longer than a dimension necessary to accommodate the jack.
  • step portion (2') directed oppositely to step portions (2) is provided.
  • wedge member (3) is mounted on the inclined face of a first step portion (2) slidably in the upward and downward direction. Between the lower end face (2b) of the step portion (2) just above the first step portion (2) and the upper end face of the wedge member (3) in parallel to said face (2b) is interposed a hydraulic jack (4), which is fixedly secured to the lower end face (2b).
  • a jack (4) is interposed between a pair of wedge members (3), (3) mounted respectively on the oppositely directed inclined faces (2a) and (2a) of the opposed step portions (2'), (2) and wound with the tensioning members (5), respectively, as shown in FIG. 4.
  • Both wedge members (3), (3) are simultaneously cause to slide in the upward and downward directions by jack (4) to impose a stretching force to the respective tensioning members (5), whereby a compression prestress may be introduced to the body (1) via the wedge members (3), (3).
  • tensioning members (5) are covered with protective mortar, and thereby the entire process has been completed.
  • FIG. 5 illustrates the case where the outer peripheral wall face (2) of the cylindrical concrete structure (A) is provided so that the outer diameter may gradually increase while going towards the bottom over the entire length in the direction of generating lines, in which case the wedge members (3) wound with annular tensioning members (5) are mounted adjacent to each other in the vertical direction, these wedge members (3) being adapted to be shifted downwardly along the outer peripheral wall surface (2) by means ofjack devices to impose a stretching force to tensioning members (5).
  • FIG. 6 shows the case where the subject method has been applied to a cylindrical concrete structure (A) such as shown in FIG. 7, in which the step portions extending in the direction of generating lines of the structure are disposed at predetermined intervals along the circumferential direction thereof. Since the operation therefor is substantially the same as the preceding embodiments, a more detailed description will be omitted. In the figure, equivalent components to those of the preceding embodiments are given the same references.
  • FIG. 8 shows the case where the method according to the present invention has been applied to a large thick cylindrical concrete structure, in which case after the innermost first layer body (1A) has been constructed similarly to the preceding embodiments and a compression prestress has been introduced thereto, a
  • second layer body (113) is constructed on its outer periphery and a prestress is introduced thereto similarly to the preceding embodiments. Subsequently similar operations may be repeated to construct a cylindrical concrete structure having a desired large thickness and having a uniform prestress introduced thereto.
  • equivalent components to those of the preceding components are given the same references.
  • FIGS. 9 and 10 show another embodiment of the present invention, in which among the step portions (2) provided on the outer peripheral surface of the body (1), but the positions of the step portions (2) in the columns adjacent to each other in the circumferential direction are staggered to each other in the direction of generating lines of the structure.
  • This structure is useful for shortening the intervals between adjacent tensioning members (5) in the vertical direction.
  • equivalent components to those of the preceding embodiments are given the same references.
  • FIGS. 11-13 show still another embodiment of the present invention.
  • notched portions (12) having a V-shaped crosssection and extending in the direct on of generating lines of the structure at predetermined intervals along the circumferential direction.
  • wedge members (13), (13) On the laterally opposed inclined faces (12a), (12b) of respective notched portions (12) are slidably provided wedge members (13), (13) respectively.
  • a jack (14) is interposed between the wedge members, and annular tensioning members (15) are wound around the outer periphery of the respective wedge members (13).
  • the tensioning members (15) are stretched by actuating jack (14) to cause both wedge members (13), (13) to slide along the inclined faces (12a), (12b) in directions opposite to each other, whereby a compression prestress may be introduced to the body (11) via the wedge members (13).
  • a method for introducing a prestress to a cylindrical concrete structure comprising the steps of providing a plurality of step portions having outer peripheral inclined faces around the periphery of said cylindrical concrete structure; positioning wedge members slidably on said inclined faces; positioning jacks for sliding said wedge members along said inclined faces; winding tensioning members around the outer peripheral surfaces of said wedge members along the circumferential direction of said structure; and stretching said tensioning members in said circumferential direction by operating said jacks to cause said wedge members to slide along said inclined faces; thereby introducing a prestress into said cylindrical concrete structure.
  • step portions are provided to extend circumferentially of said structure and to have the thickness thereof vary in the longitudinal direction of said structure.
  • step portions are provided to extend in the longitudinal direction of said structure and to have the thickness thereof vary in the circumferential direction of said structure.
  • step portions are provided to have the thickness thereof vary in the longitudinal direction of said structure, step portions adjacent in the circumferential direction of said structure being staggered in said longitudinal direction.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)
  • Reinforcement Elements For Buildings (AREA)
US00082581A 1970-09-15 1970-10-21 Method for introducing a prestress to a cylindrical concrete structure Expired - Lifetime US3711935A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3928104A (en) * 1972-05-19 1975-12-23 Stelmo Limited Method of making concrete pipes
US20140144916A1 (en) * 2011-04-20 2014-05-29 Concept Enviroment Services Pty Ltd Storage tank

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2505652C2 (ru) * 2010-03-22 2014-01-27 Сергей Львович Ситников Способ сооружения железобетонной оболочки и оболочка

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2597084A (en) * 1948-01-13 1952-05-20 Huddleston Julian Method of molding prestressed concrete structures
US3278128A (en) * 1963-01-16 1966-10-11 American Pipe & Constr Co Method of prestressing concrete pipe
US3353859A (en) * 1965-03-23 1967-11-21 Preload Co Open end structure having a positively engaged closure
US3552940A (en) * 1967-03-07 1971-01-05 Taylor Woodrow Const Ltd Circumferential stressing of concrete pressure vessels
US3568379A (en) * 1967-12-11 1971-03-09 Atomenergi Ab Prestressed concrete pressure vessel

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2597084A (en) * 1948-01-13 1952-05-20 Huddleston Julian Method of molding prestressed concrete structures
US3278128A (en) * 1963-01-16 1966-10-11 American Pipe & Constr Co Method of prestressing concrete pipe
US3353859A (en) * 1965-03-23 1967-11-21 Preload Co Open end structure having a positively engaged closure
US3552940A (en) * 1967-03-07 1971-01-05 Taylor Woodrow Const Ltd Circumferential stressing of concrete pressure vessels
US3568379A (en) * 1967-12-11 1971-03-09 Atomenergi Ab Prestressed concrete pressure vessel

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3928104A (en) * 1972-05-19 1975-12-23 Stelmo Limited Method of making concrete pipes
US20140144916A1 (en) * 2011-04-20 2014-05-29 Concept Enviroment Services Pty Ltd Storage tank

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Publication number Publication date
GB1305629A (enrdf_load_stackoverflow) 1973-02-07

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