US3541845A - Method for testing the strength of the material of cast structures,particularly concrete structures - Google Patents

Method for testing the strength of the material of cast structures,particularly concrete structures Download PDF

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Publication number
US3541845A
US3541845A US718077A US3541845DA US3541845A US 3541845 A US3541845 A US 3541845A US 718077 A US718077 A US 718077A US 3541845D A US3541845D A US 3541845DA US 3541845 A US3541845 A US 3541845A
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Prior art keywords
piston
strength
structures
concrete
counter
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Expired - Lifetime
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US718077A
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English (en)
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Peter Kierkegaard-Hansen
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PETER KIERKEGAARD HANSEN
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PETER KIERKEGAARD HANSEN
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M5/00—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings
    • G01M5/0041—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings by determining deflection or stress
    • G01M5/005—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings by determining deflection or stress by means of external apparatus, e.g. test benches or portable test systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress

Definitions

  • a counter-pressure member is placed to rest on said surface and coaxially to the piston.
  • a force is exerted towards the exterior following the axis of the two pieces, the dimensions of which are such and the spacing between them is such that the force of extraction of the piston causes the concrete to fracture forming a frusto-conical face, the piston and the counter-pressure member forming the small and the large base, respectively, of the truncated cone.
  • the invention relates to a method which can be employed for the determination and control of characteristic physical properties of the material in cast structures, in particular concrete structures.
  • the methods commonly used in performing such tests rely on separate specimens cast simultaneously with the casting of the structure and subsequently subjected to tests carried out in accordance with specific rules.
  • the tests concern primarily the determination or the checking of the compressive strength of the material, which, as a rule, is being determined by axial crushing of cylindrical specimens of given dimensions, however, the tensile strength as well as the shear strength of the material is also tested by means of appropriate methods.
  • a proposal for the determination of the shear strength has also become known based on extracting a piston cast into the concrete through a coaxial cylinder likewise cast into the concrete and having an inner diameter corresponding to the outer diameter of the piston.
  • this method is connected with great practical difiiculties,
  • the present method is of the type in which the test is performed by outwards pull on a piston embedded in the material towards the adjacent surface of the structure and the novelty of the invention consists in that the reaction of the force of this pull is transmitted to the structure by means of a counter-pressure member abutting against the surface in question with an area surrounding the projection of the piston on the surface in the direction of the force and which delineates an area of this surface which is several times larger than the projection of the piston.
  • the surface upon which the forces, affecting the part of the material of the structure influenced by the test act will be precisely defined, so that a well-defined stress distribution is obtained as well as a fracture face, the shape and size of which can be selected at discretion by coordinating the relative dimensions of the piston, the counter-pressure member and the spacing between them.
  • the dimensions of the piston and of the counterpressure member are selected in such a manner in relation to each other and to the spacing between same in the direction of the pull that together they define a truncated cone with a vertical angle of about 60, a frusto-conical fracture face will ensue with the counter-pressure member and the piston as the large and the small base, respectively, and with a half apex angle of approximately 30, i.e. fracture face, which corresponds wholly to the shape of the fracture face, produced in the axial crushing of a cylindrical specimen for the determination of the compressive strength of the material. Comparative tests have demonstrated that the requisite force of extraction in these circumstances is so close to being proportional to the compressive strength determined by the cylinder compressive strength test that the force of extraction can serve as a measure of the compressive strength of the material.
  • piston and counter-pressure memher are coordinated in such a way, that piston and counter-pressure member together define a frusto-conical surface with a very large apex angle, i.e. an apex angle of at least such a fiat fracture is formed when the piston is being extracted that the force of extraction constitutes a useful measure of the tensile strength of the material.
  • a counter-pressure member the diameter of which is only slightly larger than that of the piston, can entail forces of extraction that constitute useful measures for the strength of the material determined by means of triaxial tests.
  • 1 designates a part of the concrete structure, the surface of which is designated with 2.
  • a pull rod has been inserted through this hole and screwed down in the piston 3 and is during the test subjected to a tractional force T, which is directed in an outward direction.
  • a counter-pressure member 6 in the form of a ring is arranged, the end face of which tests on the surface of the concrete 2 and the inner diameter of which is adapted to the diameter of the piston 3 as Well as to the depth, at which same is embedded in the concrete, so that the fracture face, which is determined by the circumference of the piston 3 and the inscribed circle of the counter-pressure member 6, assumes the shape of a truncated cone, half of the apex angle of which measures about 30.
  • the fracture faces attain substantially the same shape as one half of the well-known hour-glass-shaped fracture faces, which are produced in compressive strength tests of cylindrical specimens, and tests have shown that the tractional force T required for causing the fracture in these circumstances, is in the main proportional to the compressive strength determined in such a compressive strength test of cylindrical specimen of the same concrete. It is in this connection of importance that the reaction R of the force of traction is defined exactly with regard to the piston 3 by means of the counter-pressure member 6, whereby the specific desired stress distribution, which, at the instant of fracture leads to the shown frusto-conical shaped fracture face is positively enforced.
  • the shape and size of the fracture face can be varied considerably by varying the absolute and relative values for the size of the piston 3, the counter-pressure member 6 and the spacing between these; it is only important that these dimensions be kept within such limits that a stress distribution is developed, which, at the instant of grafure leads to a fracture face which is determined by the circumference of the piston and the inner circumference of the counterpressure member.
  • the piston, the counter-pressure member and the direction of the pull should of course be coaxial as far as possible, it has, however, turned out that the requirements for accuracy in this respect are no greater than can be easily fulfilled in practice on the building site.
  • the simplest shape of the piston and of the counterpressure member is the circular one, dispensing with any need for relatively orientating the piston and the counter-pressure member, yet nothing prevents the piston and the counter-pressure member from having another shape, e.g. square, rectangular or any other polygonal shape.
  • the method can be carried out, as indicated in the drawing, also in its application in practice up to the complete fracture, since the craters produced are of no importance to the strength of the entire structure and since they can easily be filled in. In practice, it is thus possible to work with a piston diameter and an embedding depth of only approximately 25 mm. and a diameter of the counter-pressure member of approximately 55 mm.
  • Apparatus for testing the strength of structures cast from material such as concrete comprising in combination, a piston adapted to be embedded in cast material whose strength is to be tester, a pull member having one end adapted to be connected to said piston for purposes of applying a pulling force on said piston along the axial direction of said piston and pull member, and an annular counter pressure member adapted to be applied against a surface of a structure to be tested around said pull member to act an an abutment opposing the force on the structure exerted *by the piston as a result of the pulling force through said pull member, said annular counter pressure member enclosing an area several times larger than the area on the face of said piston, and being axially spaced from said piston when in use such that they define a truncated cone having an apex angle of at least about 60.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
US718077A 1968-03-29 1968-04-02 Method for testing the strength of the material of cast structures,particularly concrete structures Expired - Lifetime US3541845A (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
GB05355/68A GB1214932A (en) 1968-03-29 1968-03-29 Improvements in and relating to methods for testing the strength of the material of cast structures, such as concrete structures
CH493668A CH484423A (de) 1968-03-29 1968-04-01 Verfahren und Vorrichtung zum Prüfen der Materialfestigkeit gegossener Konstruktionen, insbesondere Betonkonstruktionen
US71807768A 1968-04-02 1968-04-02
FR146892 1968-04-03
NL6804733A NL6804733A (cs) 1968-03-29 1968-04-04

Publications (1)

Publication Number Publication Date
US3541845A true US3541845A (en) 1970-11-24

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US718077A Expired - Lifetime US3541845A (en) 1968-03-29 1968-04-02 Method for testing the strength of the material of cast structures,particularly concrete structures

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US (1) US3541845A (cs)
CH (1) CH484423A (cs)
FR (1) FR1574024A (cs)
GB (1) GB1214932A (cs)
NL (1) NL6804733A (cs)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3861201A (en) * 1972-06-12 1975-01-21 Richards Owen Method and apparatus for early strength testing of in-place concrete
US4501153A (en) * 1981-02-23 1985-02-26 Ferenc Mehes Test machine for determining concrete strength
US5592283A (en) * 1995-04-03 1997-01-07 Westinghouse Hanford Company Testing of concrete by laser ablation
US6510743B2 (en) 2000-04-13 2003-01-28 Mcafee Ralph Glenn Reusable in situ concrete test specimen apparatus and method
US7621186B2 (en) * 2007-01-31 2009-11-24 Halliburton Energy Services, Inc. Testing mechanical properties
US8601882B2 (en) 2009-02-20 2013-12-10 Halliburton Energy Sevices, Inc. In situ testing of mechanical properties of cementitious materials
US8783091B2 (en) 2009-10-28 2014-07-22 Halliburton Energy Services, Inc. Cement testing
US8794078B2 (en) 2012-07-05 2014-08-05 Halliburton Energy Services, Inc. Cement testing
US8960013B2 (en) 2012-03-01 2015-02-24 Halliburton Energy Services, Inc. Cement testing

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NO751978L (no) * 1975-06-05 1976-10-11 Sintef Fremgangsmåte for in situ bestemmelse av betongfasthet.
IT1181003B (it) * 1984-08-03 1987-09-23 Fiorenzo Meneghetti Procedimento per l'analisi in situ della qualita' di un calcestruzzo e mezzi per attuare detto procedimento
RU2293380C1 (ru) * 2005-07-18 2007-02-10 Федеральное государственное унитарное предприятие "Государственный научный центр Российской Федерации Научно-исследовательский институт атомных реакторов" Способ определения порогового коэффициента интенсивности напряжения облученных циркониевых сплавов оболочек тепловыделяющих элементов

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3182493A (en) * 1962-06-19 1965-05-11 Patterson Wilhelm Apparatus for measuring the tensile strength of green sand
DE1215958B (de) * 1964-01-25 1966-05-05 Franz Kaindl Dipl Ing Verfahren und Vorrichtung zur Guetepruefung von Beton u. dgl.

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3182493A (en) * 1962-06-19 1965-05-11 Patterson Wilhelm Apparatus for measuring the tensile strength of green sand
DE1215958B (de) * 1964-01-25 1966-05-05 Franz Kaindl Dipl Ing Verfahren und Vorrichtung zur Guetepruefung von Beton u. dgl.

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3861201A (en) * 1972-06-12 1975-01-21 Richards Owen Method and apparatus for early strength testing of in-place concrete
US4501153A (en) * 1981-02-23 1985-02-26 Ferenc Mehes Test machine for determining concrete strength
US5592283A (en) * 1995-04-03 1997-01-07 Westinghouse Hanford Company Testing of concrete by laser ablation
US6510743B2 (en) 2000-04-13 2003-01-28 Mcafee Ralph Glenn Reusable in situ concrete test specimen apparatus and method
US7621186B2 (en) * 2007-01-31 2009-11-24 Halliburton Energy Services, Inc. Testing mechanical properties
US8601882B2 (en) 2009-02-20 2013-12-10 Halliburton Energy Sevices, Inc. In situ testing of mechanical properties of cementitious materials
US8783091B2 (en) 2009-10-28 2014-07-22 Halliburton Energy Services, Inc. Cement testing
US9594009B2 (en) 2009-10-28 2017-03-14 Halliburton Energy Services, Inc. Cement testing
US8960013B2 (en) 2012-03-01 2015-02-24 Halliburton Energy Services, Inc. Cement testing
US9500573B2 (en) 2012-03-01 2016-11-22 Halliburton Energy Services, Inc. Cement testing
US8794078B2 (en) 2012-07-05 2014-08-05 Halliburton Energy Services, Inc. Cement testing

Also Published As

Publication number Publication date
FR1574024A (cs) 1969-07-11
CH484423A (de) 1970-01-15
GB1214932A (en) 1970-12-09
NL6804733A (cs) 1969-10-07

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