US3603141A - Devices for estimating the stress in concrete structures - Google Patents
Devices for estimating the stress in concrete structures Download PDFInfo
- Publication number
- US3603141A US3603141A US888306A US3603141DA US3603141A US 3603141 A US3603141 A US 3603141A US 888306 A US888306 A US 888306A US 3603141D A US3603141D A US 3603141DA US 3603141 A US3603141 A US 3603141A
- Authority
- US
- United States
- Prior art keywords
- concrete
- stress
- bore
- deflection
- estimating
- 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.)
- Expired - Lifetime
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Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C13/00—Pressure vessels; Containment vessels; Containment in general
- G21C13/02—Details
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
- G01B5/30—Measuring arrangements characterised by the use of mechanical techniques for measuring the deformation in a solid, e.g. mechanical strain gauge
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C17/00—Monitoring; Testing ; Maintaining
- G21C17/003—Remote inspection of vessels, e.g. pressure vessels
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Definitions
- a reinforced-concrete structure is provided with a bore extending into the concrete mass from one face and an annular member, whose deflection in terms of applied stress is known, set in the wall of the bore, the member having a linear dimension measurable from within the bore which is indicative ofthe deflection DEVICES FOR ESTIMATING THE STRESS IN CONCRETE STRUCTURES BACKGROUND OF THE INVENTION
- This invention relates to concrete structures which operate under stress.
- the invention chiefly relates to concrete pressure vessels which have been prestressed to eliminate, as far as is practicable, the formation of tensile stresses.
- the specification will describe the invention in terms of its application to prestressed-concrete pressure vessels.
- Prestressed-concrete pressure vessels are usually instrumented heavily, even when the particular design in not a novel one, with the object of obtaining information about stresses which develop in the wall under various mechanical and thermal loads and of monitoring the effectiveness of the prestressing system.
- As a result of this need to monitor stresses in massive concrete it has been common practice, hitherto, to use embedded strain gauges at various parts of the concrete from which, one can calculate the stress, knowing the modulus. The validity of this method depends upon the modulus remaining substantially constant. However it can be shown that this value varies widely during the life of the concrete. It is evident, therefore, that advantage is to be gained if the stress in the concrete be measured directly and if this measurement can be monitored while the pressure vessel is in use.
- a reinforced-concrete structure is provided with a bore extending into the concrete mass from one face thereof and an annular member set in the wall of the bore, an annular member whose deflection in terms of applied stress is known, the member having a linear dimension measurable from within the bore which is indicative of the deflection.
- FIG. I a medial cross section through a bore in a massive structure which forms part of a prestressed concrete pressure vessel
- FIG. 2 a cross section on the line IIlI of FIG. 1.
- the bore 1 extends through the concrete wall 2 being closed on the inner face of the vessel by the vessel liner 3 carrying the usual heat insulation 4.
- a collar 5 which has a number of stud fastenings for securing a closure plate not shown.
- the bore wall is lined throughout its length with a steel thimble 6. Attention is directed to two enlarged-diameter portions of the bore namely at axially spaced positions 7 and 8.
- annular member At each enlarged-diameter portion an annular member is set into the wall of the bore.
- the annular member comprises two resilient elliptical rings, 9, 10 fixed together in planes at right angles and whose deflection in terms of applied stress in known.
- the inner surface of each elliptical ring is shaped as a knife edge as at 9a, 10a, providing reference surfaces from which diametric measurements may be made to gain an indication of deflections of the rings and hence of the surrounding concrete.
- a number of hooks, as at 11 are welded to the periphery of the rings.
- the annular members may be assembled in a preformed thimble which is placed in position in preparation for concreting; as it is laid, cover plates fitted over the outer mouth of the thimble will ensure cleanliness of the interior until and after the concrete has set.
- cover plate is removed and a pair of precision calipers is inserted within the thimble into a position adjacent the annular member and the calipers expanded to measure the diametric distances between the knife edges.
- a dial gauge transducer or other measurement device may be set up within the thimble to measure any deflection of the annular members, and this may be trans mitted to a data logger, located at some central position, receiving similar information from bores at other positions in the structure. In this way the whole stress patterns in the concrete structure could be continuously monitored.
- single circular annular rings may be employed at each measuring point in place of the crossed elliptical rings described, with considerable simplification to the thimble unit and to the measuring device.
- a reinforced-concrete structure having a bore extending into the concrete mass from one face thereof and a member set into the bore wall comprising two rings lying in intersecting planes at right angles to one another, the rings being joined together where they intersect, the deflection of the member in terms of applied stress being known such that deflection measurements can provide a measure of stress within the concrete.
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- General Physics & Mathematics (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
- Reinforcement Elements For Buildings (AREA)
Abstract
A reinforced-concrete structure is provided with a bore extending into the concrete mass from one face and an annular member, whose deflection in terms of applied stress is known, set in the wall of the bore, the member having a linear dimension measurable from within the bore which is indicative of the deflection.
Description
United States Patent Inventor Alfred Norman Kinkead Winlrith, England Apple No. 888,306 Filed Dec. 29, 1969 Patented Sept. 7, 1971 Assignee United Kingdom Atomic Energy Authority London, England Priority Jan. 10, 1969 Great Britain 1731/69 DEVICES FOR ESTIMATING THE STRESS 1N CONCRETE STRUCTURES 1 Claim, 2 Drawing Figs.
' U.S. Cl 73/88 E Int. Cl G01b 5/30 Field of Search 73/88 R, 88
E, 88.5 R, 141 A;33/1 H, 147 1) [56} References Cited UNlTED STATES PATENTS 1,670,981 5/1928 Perkins et a1. 73/88 EX 2,898,761 8/1959 Hast 73/88 E 3,132,319 5/1964 Brooks, Jr. 73/885 R X 3,273,382 9/1966 Fonash 73/885 R 3,447,367 6/1969 Taylor 73/885 R FORElGN PATENTS 226,589 6/1959 Australia 73/88 E 151,797 10/1955 Sweden 73/88 E Primary Examiner-Char1es A. Ruehl AttorneyLarson, Taylor & Hinds ABSTRACT: A reinforced-concrete structure is provided with a bore extending into the concrete mass from one face and an annular member, whose deflection in terms of applied stress is known, set in the wall of the bore, the member having a linear dimension measurable from within the bore which is indicative ofthe deflection DEVICES FOR ESTIMATING THE STRESS IN CONCRETE STRUCTURES BACKGROUND OF THE INVENTION This invention relates to concrete structures which operate under stress. The invention chiefly relates to concrete pressure vessels which have been prestressed to eliminate, as far as is practicable, the formation of tensile stresses. The specification will describe the invention in terms of its application to prestressed-concrete pressure vessels.
Prestressed-concrete pressure vessels are usually instrumented heavily, even when the particular design in not a novel one, with the object of obtaining information about stresses which develop in the wall under various mechanical and thermal loads and of monitoring the effectiveness of the prestressing system. As a result of this need to monitor stresses in massive concrete it has been common practice, hitherto, to use embedded strain gauges at various parts of the concrete from which, one can calculate the stress, knowing the modulus. The validity of this method depends upon the modulus remaining substantially constant. However it can be shown that this value varies widely during the life of the concrete. It is evident, therefore, that advantage is to be gained if the stress in the concrete be measured directly and if this measurement can be monitored while the pressure vessel is in use.
SUMMARY OF THE INVENTION According to the invention a reinforced-concrete structure is provided with a bore extending into the concrete mass from one face thereof and an annular member set in the wall of the bore, an annular member whose deflection in terms of applied stress is known, the member having a linear dimension measurable from within the bore which is indicative of the deflection. a
DESCRIPTION OF THE DRAWING In order that the invention may be better understood a practical application thereof will now be described with reference to the accompanying drawing which shows in FIG. I a medial cross section through a bore in a massive structure which forms part of a prestressed concrete pressure vessel;
FIG. 2 a cross section on the line IIlI of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT The bore 1 extends through the concrete wall 2 being closed on the inner face of the vessel by the vessel liner 3 carrying the usual heat insulation 4. At the outer face of the wall there is a collar 5 which has a number of stud fastenings for securing a closure plate not shown. The bore wall is lined throughout its length with a steel thimble 6. Attention is directed to two enlarged-diameter portions of the bore namely at axially spaced positions 7 and 8.
At each enlarged-diameter portion an annular member is set into the wall of the bore. The annular member comprises two resilient elliptical rings, 9, 10 fixed together in planes at right angles and whose deflection in terms of applied stress in known. The inner surface of each elliptical ring is shaped as a knife edge as at 9a, 10a, providing reference surfaces from which diametric measurements may be made to gain an indication of deflections of the rings and hence of the surrounding concrete. To key each ring to the concrete a number of hooks, as at 11 are welded to the periphery of the rings. The annular members may be assembled in a preformed thimble which is placed in position in preparation for concreting; as it is laid, cover plates fitted over the outer mouth of the thimble will ensure cleanliness of the interior until and after the concrete has set. When it is required to check the stress in the concrete, the cover plate is removed and a pair of precision calipers is inserted within the thimble into a position adjacent the annular member and the calipers expanded to measure the diametric distances between the knife edges. These measurements are compared with those taken in the as manufactured condition and any difference can be used to determine stresses (in planes at right angles) to which the annular members and hence the concrete has been subjected, due allowance for temperature differences being made in the calculation.
If desired, a dial gauge transducer or other measurement device may be set up within the thimble to measure any deflection of the annular members, and this may be trans mitted to a data logger, located at some central position, receiving similar information from bores at other positions in the structure. In this way the whole stress patterns in the concrete structure could be continuously monitored.
In cases where stresses are known to remain essentially normal to the axis of the thimble, single circular annular rings may be employed at each measuring point in place of the crossed elliptical rings described, with considerable simplification to the thimble unit and to the measuring device.
I claim:
l. A reinforced-concrete structure having a bore extending into the concrete mass from one face thereof and a member set into the bore wall comprising two rings lying in intersecting planes at right angles to one another, the rings being joined together where they intersect, the deflection of the member in terms of applied stress being known such that deflection measurements can provide a measure of stress within the concrete.
Claims (1)
1. A reinforced-concrete structure having a bore extending into the concrete mass from one face thereof and a member set into the bore wall comprising two rings lying in intersecting planes at right angles to one another, the rings being joined together where they intersect, the deflection of the member in terms of applied stress being known such that deflection measurements can provide a measure of stress within the concrete.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB173169 | 1969-01-10 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3603141A true US3603141A (en) | 1971-09-07 |
Family
ID=9727009
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US888306A Expired - Lifetime US3603141A (en) | 1969-01-10 | 1969-12-29 | Devices for estimating the stress in concrete structures |
Country Status (8)
Country | Link |
---|---|
US (1) | US3603141A (en) |
BE (1) | BE744065A (en) |
CH (1) | CH516140A (en) |
DE (1) | DE1965814A1 (en) |
FR (1) | FR2028101A1 (en) |
GB (1) | GB1233691A (en) |
LU (1) | LU60153A1 (en) |
NL (1) | NL7000294A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AT388615B (en) * | 1983-02-09 | 1989-08-10 | Holzmann Philipp Ag | DEVICE FOR MEASURING THE CUT SIZE IN TUNNEL LINING |
EP1830181A1 (en) * | 2006-03-02 | 2007-09-05 | Igor Gennadievich Korolev | Method of reinforced concrete roof or floor carrying capacity monitoring |
WO2011060214A1 (en) * | 2009-11-13 | 2011-05-19 | Smart Structures, Inc. | Integrity monitored concrete pilings |
US20180120284A1 (en) * | 2016-07-08 | 2018-05-03 | Tsinghua University | Concrete temperature stress testing machine system and temperature deformation self-compensation method |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1670981A (en) * | 1925-12-01 | 1928-05-22 | Wayne A Perkins | Device for stress measuring or testing |
US2898761A (en) * | 1954-01-20 | 1959-08-11 | Hast Nils Bernhard | Ascertaining stresses and deformations in solid loaded materials |
US3132319A (en) * | 1963-08-30 | 1964-05-05 | Budd Co | Transducer arrangement |
US3273382A (en) * | 1963-08-20 | 1966-09-20 | Raymond L Fonash | Apparatus to determine horizontal and vertical loads in landing gear of aircraft |
US3447367A (en) * | 1967-04-19 | 1969-06-03 | Gen Electric | Load cell with removable,low hysteresis load sensors |
-
1969
- 1969-01-10 GB GB173169A patent/GB1233691A/en not_active Expired
- 1969-12-29 US US888306A patent/US3603141A/en not_active Expired - Lifetime
- 1969-12-30 DE DE19691965814 patent/DE1965814A1/en active Pending
-
1970
- 1970-01-06 BE BE744065D patent/BE744065A/en unknown
- 1970-01-07 LU LU60153D patent/LU60153A1/xx unknown
- 1970-01-08 FR FR7000642A patent/FR2028101A1/fr not_active Withdrawn
- 1970-01-09 CH CH24870A patent/CH516140A/en not_active IP Right Cessation
- 1970-01-09 NL NL7000294A patent/NL7000294A/xx unknown
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1670981A (en) * | 1925-12-01 | 1928-05-22 | Wayne A Perkins | Device for stress measuring or testing |
US2898761A (en) * | 1954-01-20 | 1959-08-11 | Hast Nils Bernhard | Ascertaining stresses and deformations in solid loaded materials |
US3273382A (en) * | 1963-08-20 | 1966-09-20 | Raymond L Fonash | Apparatus to determine horizontal and vertical loads in landing gear of aircraft |
US3132319A (en) * | 1963-08-30 | 1964-05-05 | Budd Co | Transducer arrangement |
US3447367A (en) * | 1967-04-19 | 1969-06-03 | Gen Electric | Load cell with removable,low hysteresis load sensors |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AT388615B (en) * | 1983-02-09 | 1989-08-10 | Holzmann Philipp Ag | DEVICE FOR MEASURING THE CUT SIZE IN TUNNEL LINING |
EP1830181A1 (en) * | 2006-03-02 | 2007-09-05 | Igor Gennadievich Korolev | Method of reinforced concrete roof or floor carrying capacity monitoring |
WO2011060214A1 (en) * | 2009-11-13 | 2011-05-19 | Smart Structures, Inc. | Integrity monitored concrete pilings |
US20110115639A1 (en) * | 2009-11-13 | 2011-05-19 | Smart Structures, Inc. | Integrity monitored concrete pilings |
US20180120284A1 (en) * | 2016-07-08 | 2018-05-03 | Tsinghua University | Concrete temperature stress testing machine system and temperature deformation self-compensation method |
US10060901B2 (en) * | 2016-07-08 | 2018-08-28 | Tsinghua University | Concrete temperature stress testing machine system and temperature deformation self-compensation method |
Also Published As
Publication number | Publication date |
---|---|
CH516140A (en) | 1971-11-30 |
NL7000294A (en) | 1970-07-14 |
LU60153A1 (en) | 1970-03-09 |
GB1233691A (en) | 1971-05-26 |
DE1965814A1 (en) | 1970-07-23 |
BE744065A (en) | 1970-06-15 |
FR2028101A1 (en) | 1970-10-09 |
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