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WO1993011314A1 - Methode permettant d'accroître au maximum la charge admissible d'ouvrages en optimalisant le recours aux pieces de renfort et aux elements de renfort similaires - Google Patents

Methode permettant d'accroître au maximum la charge admissible d'ouvrages en optimalisant le recours aux pieces de renfort et aux elements de renfort similaires Download PDF

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Publication number
WO1993011314A1
WO1993011314A1 PCT/SE1992/000840 SE9200840W WO9311314A1 WO 1993011314 A1 WO1993011314 A1 WO 1993011314A1 SE 9200840 W SE9200840 W SE 9200840W WO 9311314 A1 WO9311314 A1 WO 9311314A1
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WO
WIPO (PCT)
Prior art keywords
elements
supporting
reinforcement
shape
beams
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/SE1992/000840
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English (en)
Inventor
Lars Svensson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of WO1993011314A1 publication Critical patent/WO1993011314A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D22/00—Methods or apparatus for repairing or strengthening existing bridges ; Methods or apparatus for dismantling bridges
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B5/00—Floors; Floor construction with regard to insulation; Connections specially adapted therefor
    • E04B5/16—Load-carrying floor structures wholly or partly cast or similarly formed in situ
    • E04B5/17—Floor structures partly formed in situ
    • E04B5/23—Floor structures partly formed in situ with stiffening ribs or other beam-like formations wholly or partly prefabricated
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B5/00—Floors; Floor construction with regard to insulation; Connections specially adapted therefor
    • E04B5/43—Floor structures of extraordinary design; Features relating to the elastic stability; Floor structures specially designed for resting on columns only, e.g. mushroom floors
    • 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
    • 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
    • E04G23/00—Working measures on existing buildings
    • E04G23/02—Repairing, e.g. filling cracks; Restoring; Altering; Enlarging
    • E04G23/0218—Increasing or restoring the load-bearing capacity of building construction elements

Definitions

  • This invention relates to a method for by optimization of the degree of utilization of reinforcement and the like load carrying elements such as flanges of supporting beams maximize the load carrying capacity of structures where on utilization of conventional reinforcement systems the load carrying ability would be insufficient if not the amount of reinforcement and consequently the volume of the structure was allowed to increase in an undesirable amount.
  • structures may be mentioned decks, framing of joists, entry and exit ramps, drive bridges preferably in new production and preferably existing bridges, quays, viaducts and the like where the load carrying capacity because of changed conditions have become insufficient.
  • Calculations of the reinforcement for say a vault or a floor structure are normally based on so called slack reinforcement, i.e. that the reinforcement is put in and connected together into a continuous system but it is left passive and is not put under tension. After the casting of the concrete, the concrete and the reinforcement will cooperate and form a monolitic body. If in some cases the demands on a floor structure are higher than usual, the reinforcement is increased, sometimes there are reasons to arrange underslung stiffenings but reinforcement is normally achieved by addition, the bigger the load, the bigger amount of reinforcement and, consequently, a more voluminous structure, greater dead weight and also increased stress acting against the foundations or the like.
  • bridges are strengthened by tension cables added giving a tension force in its most stiff directions, that is longitudinally relatively to the said unit to be put under tension.
  • Such strengthening can also include casting of a supplementary structure to a concrete bridge or adding to steel lattice work supplementing strengthening plates.
  • One aspect of this invention is to on new production by using or utilizing the qualities of the reinforcement and/or strengthening material make it possible to use those up to an optimum in order to get less voluminous casting constructions but retaining or increasing the carrying ability and this without essentially increasing the bias on adjoining structural details.
  • Another aspect with this invention is to make it possible to by a minimum of work effort and material make it possible to strengthen existing bridges, quays, floors and the like where present structures already have been made use of to full extent.
  • This invention is based on the idea of adding to a structure or a system of structures in order to strengthen or increase the supporting ability, strengthening elements without incurring true statical cooperation and in such a way that the strengthening element not directly participates in supporting load, i.e. with minimum activity.
  • a preferred embodiment may be used preferably weak or slender beams or girders of high tensile strength steel which are put under tension transversally towards the object which is to be or is the basic structure, alternatively supported by stable abutments or other stationary supports .
  • Beams or girders put under tension in such a way do not participate in supporting loads, but stay with essentially constant distribution of tensions. The risk for fatigue stress in the material is thereby eliminated.
  • one or more beams or structures or similar elements which are put under tension between stationary supports and loaded system biassed thereby with equally heavy force needed to bring about the deformation in this case straighten the beams or the like from their unbiassed position to final tension position at the supporting structure.
  • Figures 3a, 3b and 4 schematically illustrate the method on strengthening a frame girder bridge shown as it is before and after a strengthening work
  • FIG. 5 schematically and in a side view, shows a bridge arranged with strengthenings according to "the invention
  • Figure 6 is a cross section through the bridge according to Figure 5 along the line A-A in Figure 5,
  • Figure 7 is a cross section through the bridge according to Figure 5 along the cross girder and the line B-B,
  • Figures 8, 9, 10 and 11 schematically and in a broken-out cross section show the edge portions of a bridge deck and ho a pre-bent beam is clamped and mounted in place.
  • Steel materials available today as well as other available materials can thanks to an improved material control and more secure methods on manufacturing and the determination of tensile strength be loaded far higher than earlier known materials and up towards figures close to a point of maximum load or breaking point.
  • the material will thus be loaded, normally under large deformation, up to a remote or far limit of inherent elasticity but on this side of the limit where yielding portending fracturing or'rupturing occurs. As statical cooperation is avoided this can be done without risk for fatigue. This applies especially to so called high tensile steel which may be permanently loaded up to deformation limit without resulting in any load variation.
  • One of the basic thoughts behind this invention is to utilize the passive action of added or subsequently added elements and allow those to excert a counterforce or back pressure brought to by bias existing or intended loaded or supporting elements and act in a direction opposite to the load loading the structure without having the added elements biassed by further loads other than marginal ones under payload or working load.
  • Figures 1 and 2 show schematically a mould device 1 or casting a concrete floor to be strenthen by using the method according to this invention.
  • a form work arranged in an ordinary way on ledgers carried by posts 2 there is a essentially conventional reinforcement 3.
  • slender high tensile steel beams 5 in advance bent are carried by appropriate end abutments 4 and the beams are intended to be loaded or tightened by means of drawing device 6 so that they take up an approximately straight position, whereon the far limit of the inherent elasticity may be approached.
  • drawing devices anchored at a structure below or the like the beams are kept in their straight position during the mounting of completing reinforcement and the casting of the concrete into the form.
  • the drawing device will be slackended and removed as well as the form work and the posts wherein, the force necessary to keep the beams straight and pressed down instead is given by the reinforced concrete casting itself. Without real cooperation with the reinforced concrete casting the beams will bias the same with an upward force corresponding to the force necessary to deform, i.e. bend the beams down to straight position. It is also possible to adjust this biassing force so that the beams essentially support the whole weight of the concrete floor, which in turn in this case will be biassed by moving added loads only.
  • FIG. 3a Another application is at existing constructions and in Figures 3a, 3b and 4 a bridge of frame girder type is designated 10.
  • the bridge is presumed to carry a load of 20 tons, whereas the desired requirement on carrying ability according to the new norms is 35 tons. Insufficient load carrying capacity of that extent, today normally results in demolition of the existing bridge and the building of a new built one. Thanks to this invention the existing bridge may be strengthen in a simple and far less expensive way.
  • Figure 3b is shown from the one side a strengthening girder 12 which together with one or more such ones is intended to be mounted at the bridge 10 in order to increase its load carrying capacity.
  • the girder 12 like the girders 5 above is in its non-mounted position faintly curved but the surfaces 13 arranged along the underside of the bridge and against which the girder is to be mounted is straight or level .
  • the girder 12 and further such girders fit against surfaces 13 they have to be straightened out and this is preferably done by means of drawing devices attached at the ends of the girders and arranged to pull the same upwardly. By doing this the girders will be charged with a load corresponding to the force by means of which they subsequently will bias the bridge.
  • the girders 12 are so constructed and dimensioned that for the straightening out of the same from the curved shape a force of predeterminable value is needed and the combined forces biassing the beams are to correspond with the necessary increase of load carrying capacity.
  • Frame girder bridges of the kind illustrated in Figures 5, 6 and 7 are very common along the roads and such bridges the building of which started more than 50 years ago do not have the load carrying capacity necessary today. Bridges of the kind just mentioned can by means of the method according to this invention in a simple way be strengthened well up to the figures relevant today and this while the traffic on the bridge may be allowed to continue during the works without being disturbed to any mentionable exten .
  • a couple of slender high tensile girders 12 which in unbiassed position have an upwardly bent shape but which after mounting followed by pressing down of the curved shape will be straight.
  • the mounting is facilitated if the ends of the girders are allowed to rest against spacer bodies 15 while between the middle portion of the girders and the corresponding portion of the bridge there are inserted so called flat jacks 16, i.e. jacks with a minimum height which after the pressing down of the girders and straightening out of the same may be left in the structure filled with concrete in order to together with conventional pads or spacers 15, keep the girders in intended positions relatively to the bridge.
  • Figures 5-7 show the girders in mounted position, i.e. straightened out, and Figure 6 illustrates how the girders engage the under side of the bridge between the longitudinal beams while Figure 7 illustrates how recesses 17 have been arranged in existing casted lateral beams T or the beams 12.
  • the recesses 17 may be refilled with concrete after the mounting of the girders.
  • bridges include monolitic concrete structures with or without underslung stiffening beams resting on appropriate abutments and have either along the edges arranged stiffeners or abutments along the edges alternatively and abutments along the edges and stiffening girders further inwardly.
  • the slender added components may be initially straight and be deformed during their mounting.

Landscapes

  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Bridges Or Land Bridges (AREA)

Abstract

Méthode permettant d'accroître la charge admissible d'une structure de soutien en optimalisant le recours aux éléments de renfort ajoutés à cette structure. La méthode consiste à ajouter à une telle structure, en plus des moyens existants ou calculés permettant d'obtenir une coopération entre les éléments de la structure, un ou plusieurs éléments de soutien de formes allongées, par exemple des poutres (5, 12), qui, avant et pendant le montage, sont chargées jusqu'à déformation et reliées à la structure dans cette position.
PCT/SE1992/000840 1991-12-04 1992-12-04 Methode permettant d'accroître au maximum la charge admissible d'ouvrages en optimalisant le recours aux pieces de renfort et aux elements de renfort similaires Ceased WO1993011314A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI915726 1991-12-04
FI915726A FI915726L (fi) 1991-12-04 1991-12-04 Saett att genom optimering av utnyttjandegraden hos armering och liknande foerstaerkningselement maximera baerfoermaogan hos konstruktioner

Publications (1)

Publication Number Publication Date
WO1993011314A1 true WO1993011314A1 (fr) 1993-06-10

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1992/000840 Ceased WO1993011314A1 (fr) 1991-12-04 1992-12-04 Methode permettant d'accroître au maximum la charge admissible d'ouvrages en optimalisant le recours aux pieces de renfort et aux elements de renfort similaires

Country Status (3)

Country Link
AU (1) AU3121193A (fr)
FI (1) FI915726L (fr)
WO (1) WO1993011314A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101022249B1 (ko) * 2010-08-23 2011-03-21 (주)미래기술단 견고한 설치구조를 갖는 면벽식 라멘교 및 그 시공방법

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2822068A (en) * 1953-03-18 1958-02-04 Hendrix Hubert Lee Beam structures and method of applying tension thereto to reverse the stress therein
US4607470A (en) * 1985-01-28 1986-08-26 Concrete Systems, Inc. Pre-stressed construction element
US4704830A (en) * 1986-02-06 1987-11-10 Magadini Charles R Increasing the load carrying capacity of beams

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2822068A (en) * 1953-03-18 1958-02-04 Hendrix Hubert Lee Beam structures and method of applying tension thereto to reverse the stress therein
US4607470A (en) * 1985-01-28 1986-08-26 Concrete Systems, Inc. Pre-stressed construction element
US4704830A (en) * 1986-02-06 1987-11-10 Magadini Charles R Increasing the load carrying capacity of beams

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
DERWENT'S ABSTRACT, No. 83-837702/49, week 8349; & SU,A,994 657 (KAZAN ENG CONS), 12 February 1983. *
DERWENT'S ABSTRACT, No. 87-176620/25, week 8725; & SU,A,1 268 701 (KAZAN ENG CON INST), 7 November 1986. *
DERWENT'S ABSTRACT, No. 89-276657/38, week 8938; & SU,A,1 465 519 (MIN CON NORTH WEST), 15 March 1989. *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101022249B1 (ko) * 2010-08-23 2011-03-21 (주)미래기술단 견고한 설치구조를 갖는 면벽식 라멘교 및 그 시공방법

Also Published As

Publication number Publication date
AU3121193A (en) 1993-06-28
FI915726A7 (fi) 1993-06-05
FI915726L (fi) 1993-06-05
FI915726A0 (fi) 1991-12-04

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