US3631831A

US3631831A - Improvements in or relating to concrete structure

Info

Publication number: US3631831A
Application number: US773420A
Authority: US
Inventors: William Morley Sutherland
Original assignee: CERTIFIED CONCRETE Ltd
Current assignee: CERTIFIED CONCRETE Ltd
Priority date: 1967-11-06
Filing date: 1968-11-05
Publication date: 1972-01-04
Anticipated expiration: 1989-01-04
Also published as: GB1233778A

Abstract

The manufacture of a channel-shaped ferroconcrete unit in which a ferroconcrete bottom slab and two ferroconcrete side slabs having pretensioned tendons or passageways passing from the bottom slab to the remote edge of each side slab are arranged in channel formation with the tendons being stressed whereby suitable stress loads in the tendons are realized within the bottom slab and side slabs. The pretensioned tendons pass around radiused bends at each junction between the bottom slab and one of the side slabs.

Description

United States Patent 2,885,882 5/1959 Fulleretal William Morley Sutherland Auckland, New Zealand 773,420

Nov. 5, 1968 Jan. 4, 1972 Certified Concrete Limited Auckland, New Zealand Nov. 6, 1967 New Zealand Inventor Appl. No. Filed Patented Assignee Priority IMPROVEMENTS IN OR RELATING TO CONCRETE STRUCTURE 5 Claims, 19 Drawing Figs.

US. Cl 114/65 A, 52/227 Int. Cl B631) 11/04, B635 5/14 Field of Search I 14/65. 1

References Cited UNITED STATES PATENTS 179,306 6/1876 dI-Iemecourt... 52/227 X 2,042,113 5/1936 Marten 52/227 2,454,403 1 H1948 Palmieri I 14/65 2,903,875 9/1959 Bonatz et a1. 52/227 X 2,966,008 12/ 1960 Gerholm et al. 52/227 FOREIGN PATENTS 897,279 5/1944 France I 14/77 1,479,523 3/1967 France 52/230 Primary ExaminerAndrew H. Farrell Attorney-Holman & Stern ABSTRACT: The manufacture of a channel-shaped ferroconcrete unit in which a ferroconcrete bottom slab and two ferroconcrete side slabs having .pretensioned tendons or passageways passing from the bottom slab to the remote edge of each side slab are arranged in channel formation with the tendons being stressed whereby suitable stress loads in the tendons are realized within the bottom slab and side slabs. The pretensioned tendons pass around radiused bends at each junction between the bottom slab and one of the side slabs.

IMPROVEMENTS IN OR RELATING TO CONCRETE STRUCTURE This invention relates to concrete structures and particularly though not solely to concrete vessels such as barges, pontoons or ships. Previous constructions have necessitated a large amount of cast in situ work which is expensive as the molds are generally not suitable for a vessel of a different size or shape.

Therefore, it is an object of the present invention to provide a method of manufacturing concrete vessels and/or module units for ferroconcrete vessels and/or ferroconcrete vessels which go at least some distance towards overcoming the above-mentioned disadvantage and/or which will at least provide the public with a useful choice.

Accordingly, the invention consists in a method of manufacturing a channel-shaped ferroconcrete unit comprising the steps of making a ferroconcrete center slab in which tendons are pretensioned during manufacture and two ferroconcrete side slabs having said tendons or passageways therefor passing therethrough to the remote edge of each side slab, arranging said slabs in channel formation and stressing said tendons so that suitable stress loads in said tendons are obtained within said center slab and said side slabs, with said tendons passing around radiused bends at each junction between said center slab and one of said side slabs.

In a still further aspect the invention consists in a method of manufacturing a ferroconcrete vessel such as a barge, comprising the steps of placing ready for assembly a series of modular units each unit comprising a bottom slab having pretensioned tendons therein, corner beams and side slabs, passing tendons longitudinally through passageways in said side slabs and said comer beams, post tensioning the tensions therein, passing tendons longitudinally through passageways so that the modular units combine to form the vessel bottom sides and ends and tensioning and anchoring the tendons to form a monolithic vessel.

In a still further aspect the invention consists in a ferroconcrete structure comprising at least a center and two side slabs having tendons running therethrough, with the tendons being pretensioned in at least the center slab and the same tendons being subsequently post tensioned in the side slabs.

In a still further aspect the invention consists in a ferroconcrete module unit for the hull of a vessel such as a barge comprising a bottom slab having a plurality of stressing tendons running from one edge to the opposite edge, two comer beams, one edge of each of which engages an edge of said bottom slab which has said tendons passing therethrough, each said comer slab having said tendons passed therethrough so that the tendons enter said one edge engaged with said bottom slab and leaves by an edge which is at an angle thereto and two side slabs, one edge of each of which engages one of said comer slabs on the edge at which said tendons leave the opposite edges of said side slabs having tendon anchorages thereon, said tendons passing through said side slabs, and said tendons being post tensioned in said side slabs and said comer beams to tie the slabs together to form a prestressed channelshaped unit.

In a still further aspect the invention consists in a hull of a vessel comprising a plurality of ferroconcrete module units as above set forth assembled end to end and having a bow and a stern unit, the units having pretensioned tendons passing longitudinally of the slabs forming the units in passageways provided therein, and said tendons being tensioned and anchored to form a monolithic concrete vessel.

In a still further aspect the invention consists in a ferroconcrete vessel such as a barge comprising a series of shaped modular units, each unit comprising a bottom slab, comer beams and said bottom slab, said slabs having transverse pretensioned tendons passing through passageways in said comer beams in the form of radiused bends, and through passageways in said side slabs and being posttensioned therein, further pretensioned tendons passing longitudinally of said vessel so that said modular units combine to form the vessel bottom sides and ends and said tendons being tensioned and anchored to form a monolithic vessel.

One preferred form of the invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is an exploded view of a ferroconcrete structure according to the invention in the form of a barge,

FIG. 2 is a plan view of an assembled barge,

FIG. 3 is a typical cross section of the barge shown in FIG.

FIG. 4 is a plan view of a main bottom slab,

FIG. 5 is a part side view of FIG. 4,

FIG. 6 is a plan view of a main side slab,

FIG. 7 is a side view of FIG. 6,

FIG. 8 is a part plan view of a bottom comer beam,

. 9 is a end view of FIG. 8,

. I0 is a plan view of an anchor cap beam I l is an enlarged end view of FIG. 10,

. 12 is a plan view of a diaphragm slab,

. 13 is a plan view of a deck slab,

. 14 is an end elevation of the barge,

. 15 is an enlarged view of a bottom corner joint,

. 16 is a detail of the top joint,

17 is a part side view of the bow or stem of the barge, 18 is a section taken along the line A-A of FIG. 14, and

FIG. 19 is a section taken along the line BB of FIG. 14.

Referring to the drawings, a structure is shown made up of a series of U- or channel-shaped units, with each unit in turn being assembled from slabs and beams and the units being further assembled to form a vessel, specifically a barge.

Thus for each of the main units referenced 1 to 4 in FIG. 1, there is provided a bottom slab 5, two-side slabs 6 separated from and connected to the bottom slab by two-bottom corner beams 7, a deck slab 8 and two-anchor cap beams 9, and these elements are shown assembled in FIG. 14. The dimensions of these elements transverse to the length of the barge, determined by the design characteristics of the barge but the other dimensions for example, the dimension 11 in FIG. 4 is selected by the designer so that when assembled, as seen in FIG. 2, the units will mate one against the other to provide the assembled barge.

The bottom slabs 5 have transverse tendons 12 at say l-foot spacings which are pretensioned and cast in the slab. In addition longitudinal tendon ducts 13 are provided at say 2-foot intervals with the cross section being thickened in the area of the tendons as shown at 14 in FIG. 5. The tendons 12 are extended beyond the sides 15 of the slab 5 by a suitable length as to enable them to be passed through and extend beyond the assembled comer beams 7 and side slabs 6 as will be later mentioned. Reinforcing mesh, such as 6-6-l0 HRC mesh, is used as secondary reinforcing in the bottom slabs 5, side slabs 6 and deck slabs 8. The side slabs 6 have tendon ducts 16, the spacing of which corresponds with the spacing of the tendons 12 in the bottom slab. A tendon duct I7 is provided in a thickened area 18 having a secondary reinforcing 19.

The corner beams 7 have radiused tendon ducts 20 in which the spacings and positions thereof correspond to those of the tendons l2 and ducts l6 and stirruped secondary reinforcing 21 (e.g., 6-6-6 I-IRC mesh) is provided as shown. A tendon duct 22 extends longitudinally of the beam.

Rabbets

23 and 23a are provided to receive the

edges

24 and 25 of a side slab 6 and a bottom slab 5 respectively (FIG. 15).

The deck slabs 8 are made in a similar manner to the bottom slabs 5 with tendon ducts 26 but with the transverse prestressing tendons 27 pretensioned and the ends sealed in the slab. Ducts 28 are provided near the edges spaced and positioned to correspond with the ducts 16 of the side slabs 6. The anchor cap beams 9 have anchoring depressions 29 connecting with ducts 30 spaced and positioned to correspond with the ducts l6 and tendons I2 and secondary reinforcing 31 is provided as shown.

A modular unit of the barge is assembled as seen in FIGS. 14 and 15 by threading tendons 12 of a bottom slab 5 through ducts in two-corner beams 7, ducts to in two-side slabs 6, ducts 28 in a deck slab 8, and ducts 30 in two-anchor cap beams 9. An epoxy glue is applied to mating surfaces to provide some increase in strength and to provide waterproofing at these points.

The tendons 12 are then post tensioned and it has been found that a suitable tension can be obtained in the side slabs (despite the radiused portion of the tendons in the comer beam).

The foregoing describes the assembly of a typical unit such as the units 2 and 3, FIG. 1. In

units

1 and 4 there is some variation in the bottom corner beams and bottom and deck slabs to provide for bow and stem units. Thus, the bottom slabs 32 of

units

1 and 4 each have an enlarged end 33 provided with extra secondary reinforcing 34. Similarly, the bottom slab 35 of a bow or stem unit has an enlarged end 36 and extra reinforcing 37,

ducts

38 and 39 corresponding in spacing and positions with the ducts 13. The ducts 39 terminate in tensioning anchorages shown diagrammatically at 40 in a bow or stem beam 41 shown in FIG. 18. It will be apparent that the bow and stem are symmetrical.

The side slabs 42 for the bow and stem are suitably shaped, and the bottom comer beams 43 and 44 have ends 45 and 46 shaped as shown.

The bow and stem elements are assembled into units by post-tensioning tendons extending from the bottom slab and through bottom comer beams, side slabs, deck slabs and anchor cap beams as above described in connection with the main units.

The units 1 to 4 and the bow and stem units are then assembled to form a complete barge. Diaphragms 47 (FIG. 12) are made as slabs having prestressing tendons 48 and 6-6-1 HRC mesh secondary reinforcing, three of these diaphragms are positioned between units 1 to 4 as shown, the diaphragms have

tendon ducts

49 and 50 corresponding in position and spacing to ducts l3 and 26 and

ducts

51 and 52 corresponding to

ducts

22 and 17. These diaphragms give transverse stiflening to the barge. Longitudinal post-tensioning tendons are passed through the appropriate ducts in the bottom side and deck slabs and through the ducts in the bottom comer blocks. These tendons are tensioned, and tendons 53 through the bottom slabs are clamped at the anchorages 40. Tendons 54 through the deck slabs are anchored at 55. The tendons through the bottom comer blocks may be anchored at junction 56 between the unit 4 and bow or stem unit 57 and again at 58 or the tendons may be run from bow to stem as will the bottom tendons if desired. Epoxy glue is used between mating concrete surfaces as with the unit construction.

Thus, the elements are associated into a monolithic structure, with the use of the curved ducts 20 in the comer beams 7 enabling the major anchorages to be placed above the waterline.

Clearly, the invention may be modified in many difierent ways. The slabs need not be flat so that vessels other than barges may be assembled from a series of prefabricated slabs or panels. The diaphragm and deck slabs may have apertures therein for hatches or bulkhead doors. The corner beams may be dispensed with and the radiused bend of the tendon passageways provided either in a side slab or a bottom slab or partly in each, or the comer beams may be formed in situ after positioning the side panels at an angle to the bottom panel but before post tensioning is effected.

in alternative methods of constructions a substantially planar base portion is cast at the same time as side portions around pretensioned tendons running through all three units. In the side portions, the tendons are sheathed to prevent bonding as in a normal process of pretensioning. Secondary mesh reinforcing may also be included in the slabs. After detensioning and demolding, the side portions can either by removed from the tendons or carried with the base portion to the site as a whole by means of suitable handling equipment. At the assembly site the side portions are set up in the shape required with a jointing gap left between such portions and the base portion. The tendons, which are now exposed at the comers, are radiused and sheathed with suitable radiused molds between which are ultimately cast concrete comer portions. A deck portion bridges the two side portions and the tendons pass through suitable holes lying in transverse planes in the deck portion. The comer portions are cast in place and the unit is post-tensioned by nonnal jacking at the deck and then grouted. Alternatively, the tendons can be anchored at the deck and a gap left in the comer portions when they are being cast, with the gap being filled with suitable material under pressure after it has been suitably boxed.

In a different method, the pretensioned tendons are bonded in each unit and the joint between therebetween is boxed and sealed and the tendons are stressed in that region by means of resin introduced under pressure inside the boxing.

In the deck, base and side portions, longitudinal ribs are provided having longitudinal ducts therein. A plurality of units are placed end to end and tendons running through these ducts are post tensioned to compress the units together. The longitudinal tendons also run through longitudinal ducts in suitable end units. The longitudinal stressing can be done in combinations of temporary, permanent or a variety of lengths.

The joint between adjacent units is rebated and in these rebates transverse stifleners may be positioned if extra strength is required. There may be two horizontal stiffeners, with one stiffener being adjacent the base and the other adjacent the deck. These stiffeners are held apart by means of steel or other type posts. Two vertical stiffeners bear against the ends of the horizontal stiffeners and are thus held in place. The stiffeners may be cast with openings therein to lighten the stiffeners and to provide access ways.

It will thus be seen that a high degree of standardization has been achieved for almost any shape or size of barge. The base and deck panels may be cast in any widths and the side panels in widths commensurate with the drafi of the vessel. The bow and stem units are identical and are used for vessels of any length having the beam and draft for which the bow and stem units have been designed. Because there is stressing in both transverse and longitudinal directions, a high degree of strength is obtained and a monolithic construction is achieved by use of stressing only.

Where unusual sections are required, e.g., bow and stem sections having double compound curves, ferrocement structures used either with or without pretensioned tendons therethrough may be used, with such structures being manufactured according to current techniques.

What I claim is:

l. A method of manufacturing a channel-shaped ferroconcrete unit, comprising the steps of forming a ferroconcrete center slab in which pretensioned tendons are positioned, forming two-ferro concrete side slabs through which said pretensioned tendons pass to the remote side of each side slab, arranging the slabs in channel formation and post tensioning the tendons in the side slabs so that suitable stress loads in the tendons are obtained within the center slab and the side slabs, passing said tendons around radiused bends at each junction between the center slab and one of the side slabs, and positioning corner beams between the side slabs and the center slab and positioning the radiused bends in the comer beams.

2. A method of manufacturing a ferroconcrete vessel such as a barge, comprising the steps of placing ready for assembly a series of modular units each including a bottom slab having pretensioned tendons therein, comer beams and side slabs, passing said pretensioned tendons through passageways in the side slabs and comer beams, post tensioning the tendons therein, passing pretensioned tendons longitudinally through passageways so that the modular units are combined to define the vessel bottom sides and ends, and tensioning and anchoring the longitudinal tendons to provide a monolithic vessel.

side slabs cooper-able with said center slab and through which said tendons pass, said tendons in said side slabs being post tensioned and said tendons in said side slabs being post tensioned by a suitable settable material applied under pressure to the gaps between the slabs.

5. The ferroconcrete structure as claimed in claim 4 in which said suitable settable material is selected from a cement grout and an epoxy resin.

Claims

1. A method of manufacturing a channel-shaped ferroconcrete unit, comprising the steps of forming a ferroconcrete center slab in which pretensioned tendons are positioned, forming two-ferro concrete side slabs through which said pretensioned tendons pass to the remote side of each side slab, arranging the slabs in channel formation and post tensioning the tendons in the side slabs so that suitable stress loads in the tendons are obtained within the center slab and the side slabs, passing said tendons around radiused bends at each junction between the center slab and one of the side slabs, and positioning corner beams between the side slabs and the center slab and positioning the radiused bends in the corner beams.

2. A method of manufacturing a ferroconcrete vessel such as a barge, comprising the steps of placing ready for assembly a series of modular units each including a bottom slab having pretensioned tendons therein, corner beams and side slabs, passing said pretensioned tendons through passageways in the side slabs and corner beams, post tensioning the tendons therein, passing pretensioned tendons longitudinally through passageways so that the modular units are combined to define the vessel bottom sides and ends, and tensioning and anchoring the longitudinal tendons to provide a monolithic vessel.

3. The method as claimed in claim 2 comprising mounting prestressed ferroconcrete deck slabs on at least some of the units through which post tensioned longitudinal and pretensioned transverse tendons pass, interposing diaphragm slabs between some units, fixing transverse stern and bow beams and anchoring at least some of the longitudinal tendons to such beams.

4. A ferroconcrete structure comprising at least a center slab, pretensioned tendons positioned in said center slab, two-side slabs cooperable with said center slab and through which said tendons pass, said tendons in said side slabs being post tensioned and said tendons in said side slabs being post tensioned by a suitable settable material applied under pressure to the gaps between the slabs.