GB2209791A - Removal of forces in pre-tensioned or cost tensioned tendons in concrete prior to demolition - Google Patents

Removal of forces in pre-tensioned or cost tensioned tendons in concrete prior to demolition Download PDF

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Publication number
GB2209791A
GB2209791A GB8718928A GB8718928A GB2209791A GB 2209791 A GB2209791 A GB 2209791A GB 8718928 A GB8718928 A GB 8718928A GB 8718928 A GB8718928 A GB 8718928A GB 2209791 A GB2209791 A GB 2209791A
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GB
United Kingdom
Prior art keywords
demolition
tendons
tensioned
forces
explosives
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.)
Withdrawn
Application number
GB8718928A
Other versions
GB8718928D0 (en
Inventor
Robin John Tollast
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
Priority to GB8718928A priority Critical patent/GB2209791A/en
Publication of GB8718928D0 publication Critical patent/GB8718928D0/en
Publication of GB2209791A publication Critical patent/GB2209791A/en
Withdrawn legal-status Critical Current

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Classifications

    • EFIXED CONSTRUCTIONS
    • E04BUILDING
    • E04GSCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G23/00Working measures on existing buildings
    • E04G23/08Wrecking of buildings

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Mechanical Engineering (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Working Measures On Existing Buildindgs (AREA)

Abstract

When demolishing prestressed concrete structures consideration must be given to the large forces that exist in the steel tendons. Where the demolition is taking place remote from other buildings explosives may be used to destroy the structure. Where demolition is taking place within an urban environment explosives cannot be used. In the proposed method relaxation of the tensile forces is undertaken with the application of a voltage across the ends of the tendons. The heating of the tendons produces strain in the tendons which is of opposite sign to that caused by the original applied stressing. The demolition can than take place without the risk of dangerous release of prestressed forces. <IMAGE>

Description

REMOVAL OF FORCE IN THE CABLES OF A PRESTRESSED BESM ' Description of Invention The invention consists of a method whereby the existing tensile forces within prestressed or post-tensioned beams can be released prior to such units being demolished.
The effects of the electric current in the bars or cables will cause the force in the cable to be drastically reduced thereby enabling work to break up the beam being carried out in safety.
The currents in the cables or bars will heat them up thereby causing (1) Loss of strength in the cables (2) Loss of strain in the cables (3) Loss of bond with surrounding concrete.

Claims (1)

  1. CLAIM
    The procedure described is to enable the force in a pretensioned beam to be removed prior to demolition.
    Where existing beams are demolished in open country the use of explosives can be carried out. In the town situation however explosives are not permitted and the method described, it is claimed, will provide an answer.
    The demolition of post tensioned structures is in its infancy but there will be increasing member of such demolitions of this type of structure in the future.
GB8718928A 1987-08-11 1987-08-11 Removal of forces in pre-tensioned or cost tensioned tendons in concrete prior to demolition Withdrawn GB2209791A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8718928A GB2209791A (en) 1987-08-11 1987-08-11 Removal of forces in pre-tensioned or cost tensioned tendons in concrete prior to demolition

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8718928A GB2209791A (en) 1987-08-11 1987-08-11 Removal of forces in pre-tensioned or cost tensioned tendons in concrete prior to demolition

Publications (2)

Publication Number Publication Date
GB8718928D0 GB8718928D0 (en) 1987-09-16
GB2209791A true GB2209791A (en) 1989-05-24

Family

ID=10622090

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8718928A Withdrawn GB2209791A (en) 1987-08-11 1987-08-11 Removal of forces in pre-tensioned or cost tensioned tendons in concrete prior to demolition

Country Status (1)

Country Link
GB (1) GB2209791A (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1240185A (en) * 1967-10-21 1971-07-21 Fuji Motors Corp Improvements in demolition methods
GB1542885A (en) * 1977-06-24 1979-03-28 Redpath Dorman Long Ltd Electrical de-tensioning

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1240185A (en) * 1967-10-21 1971-07-21 Fuji Motors Corp Improvements in demolition methods
GB1542885A (en) * 1977-06-24 1979-03-28 Redpath Dorman Long Ltd Electrical de-tensioning

Also Published As

Publication number Publication date
GB8718928D0 (en) 1987-09-16

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)