CN117516610A - Differential transformer type displacement sensor measuring head supporting device and construction and use methods thereof - Google Patents
Differential transformer type displacement sensor measuring head supporting device and construction and use methods thereof Download PDFInfo
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- CN117516610A CN117516610A CN202311303526.2A CN202311303526A CN117516610A CN 117516610 A CN117516610 A CN 117516610A CN 202311303526 A CN202311303526 A CN 202311303526A CN 117516610 A CN117516610 A CN 117516610A
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- 239000010959 steel Substances 0.000 claims abstract description 184
- 239000011150 reinforced concrete Substances 0.000 claims abstract description 91
- 238000012360 testing method Methods 0.000 claims abstract description 57
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- YKTSYUJCYHOUJP-UHFFFAOYSA-N [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] Chemical compound [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] YKTSYUJCYHOUJP-UHFFFAOYSA-N 0.000 claims description 17
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
- E04B1/20—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons the supporting parts consisting of concrete, e.g. reinforced concrete, or other stonelike material
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C3/00—Structural elongated elements designed for load-supporting
- E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
- E04C3/20—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of concrete or other stone-like material, e.g. with reinforcements or tensioning members
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- 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
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
- G01B7/24—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge using change in magnetic properties
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D11/00—Component parts of measuring arrangements not specially adapted for a specific variable
- G01D11/30—Supports specially adapted for an instrument; Supports specially adapted for a set of instruments
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
- G01D5/22—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature differentially influencing two coils
- G01D5/2291—Linear or rotary variable differential transformers (LVDTs/RVDTs) having a single primary coil and two secondary coils
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/12—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using combustion
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Abstract
The invention relates to a differential transformer type displacement sensor measuring head supporting device and a construction and use method thereof, belonging to the technical field of reinforced concrete beam fire tests. The problem that an LVDT measuring head cannot be placed at a specified measuring point or is not firmly placed due to the fact that the width of the section of a beam is small or loading equipment is placed when the LVDT is used for measuring the deformation of a reinforced concrete beam in the existing fire test is solved. Including first steel sheet, second steel sheet, supporting bar, fourth steel sheet and expansion bolts, be provided with expansion bolts on the first steel sheet, the second steel sheet is connected perpendicularly with the middle part of first steel sheet, and the middle part of second steel sheet is connected perpendicularly with supporting bar one end, and the supporting bar other end is connected perpendicularly with the fourth steel sheet middle part, and the fourth steel sheet is located the upper portion of second steel sheet. The invention is a supporting device which is not influenced by a loading mode, is not influenced by the size of the top surface space of the reinforced concrete beam, is firm in placement of the LVDT measuring head and is not easy to damage.
Description
Technical Field
The invention relates to a supporting device of a displacement sensor measuring head, a construction method and a use method, and belongs to the technical field of reinforced concrete beam fire tests.
Background
In various disasters, the occurrence frequency of the fire is high and the hazard is high. When a building fire disaster occurs, the mechanical properties of structural materials are deteriorated, so that the structural deformation is increased, the bearing capacity is reduced, and serious people can cause structural collapse, which constitutes serious threat to the life and property safety of people. Therefore, sufficient importance must be given to fire resistance of the building structure. In various buildings, the proportion of reinforced concrete structures is large. Compared with structural materials such as bamboo, steel and the like, the concrete is incombustible, and has lower heat conductivity coefficient, thus having better fire resistance. However, the reinforced concrete structure is severely damaged or even collapses under the combined action of long-time high temperature and load. The reinforced concrete beam is an important horizontal bearing member in a building structure, and the fire resistance of the building structure is directly influenced by the fire safety of the building structure, so that enough attention should be paid to the fire resistance of the reinforced concrete beam.
Fire testing is a common method for evaluating the fire resistance of structural members, and has the advantage of being direct and reliable. The basic flow is to put the structural component into a fire test furnace, and according to the actual demand, the test component can be loaded or not, and then the fire test furnace is heated based on an ISO834 international standard heating curve. And in the test process, parameters such as temperature, deformation, crack width, fire resistance limit and the like of the structural member are measured to evaluate the fire resistance of the member. Among the parameters, the deformation of the components under fire is one of important standards for judging whether the components reach the fire resistance limit, and the method has important guiding significance for the safety identification, reinforcement and repair of the post-disaster structure of fire rescue and personnel evacuation. Therefore, in the case of performing a fire test, deformation of the structural member is generally measured as an important parameter. At present, differential transformer type displacement sensor LVDT is adopted by various universities and colleges and research institutions to measure deformation of structural members.
The LVDT is a sensor for converting the deformation to be measured into an electric signal, and can be used for measuring the relative displacement between objects, the length change of the objects and the geometric dimensions of parts; the method can also be used for measuring the deformation of various models, test pieces, rock masses, concrete, metal or nonmetal material components under the action of force or temperature; meanwhile, it can also measure various physical quantities, such as pressure, force, tension, liquid level change, etc., which are previously converted into linear displacement. The LVDT comprises a differential transformer, a transducer circuit board, a metal shell, a guide rod, a measuring head, a cable and a wire clamp, wherein the differential transformer and the transformer circuit board are uniformly packaged in the metal shell. The working principle of the LVDT is an electromagnetic induction principle: the method is characterized in that epoxy glass cloth, stainless steel and other materials are adopted as coil frameworks, a group of primary coils and two groups of secondary coils are wound on the frameworks by using enameled wires with different wire diameters, the working mode of the method depends on the movement of an iron core in the coil frameworks, when the primary coils are supplied with alternating voltage excitation voltage with certain frequency, the movement of the iron core in the coil changes the distribution of a space magnetic field, so that the mutual inductance of the primary coil and the secondary coil is changed, the secondary coils generate induced electromotive force, the mutual inductance is also different along with the difference of the positions of the iron core, the induced electromotive force generated by the secondary coils is also different, thus the displacement of the iron core is changed into a voltage signal, and the voltage difference of the two secondary coils is in linear relation with the displacement because the voltage polarities of the two secondary coils. One end of the LVDT measuring rod is a measuring head, the other end of the LVDT measuring rod is connected with the iron core in the coil framework, the measuring rod can freely stretch and retract in the metal shell of the LVDT and is guided by the guide rod so as to ensure that the measuring rod vertically enters and exits the metal shell, and therefore, the movement of the LVDT measuring rod is the movement of the iron core in the coil framework. When the iron core is positioned at the positive middle position of the coil, the induction voltages of the coils are equal but the phases are opposite, and the voltage difference is zero; when the iron core moves rightwards from the middle position of the coil, the voltage induced by the secondary coil on the right is larger than that of the secondary coil on the left, and the voltage difference value output by the two coils linearly changes along with the displacement of the iron core, which is half of the effective measurement range of the LVDT; on the contrary, when the iron core moves leftwards from the middle position of the coil, the voltage induced by the secondary coil on the left side is larger than that of the secondary coil on the right side, and the voltage difference value output by the two coils still linearly changes along with the displacement of the iron core, which is the other half of the effective measuring range of the LVDT.
When the LVDT is used for measuring the deformation of the structural component, the metal shell of the structural component is required to be fixed on a stationary reference object, and then the measuring head of the structural component is placed at a position where the structural component is required to measure the deformation. When the deformation measurement is carried out on the reinforced concrete beam, the use of the LVDT is greatly different from that of the LVDT under the normal temperature environment and the fire disaster test condition, because the temperature of the reinforced concrete beam is room temperature under the normal temperature environment, and static reference objects can be placed above the top surface and below the bottom surface of the beam to fix the LVDT; in order to better simulate the actual condition of the beam in a fire under the fire test condition, liang Sanmian is usually fired, i.e. the bottom surface and the two side surfaces of the beam are fired, and the top surface is not fired, so that only the stationary reference object can be arranged on the top surface of the beam, and the measuring head of the LVDT needs to be arranged on the top surface of the beam. If the reinforced concrete beam is not loaded in the fire test, the measuring head of the LVDT can be directly placed on the measuring point on the top surface of the beam. In actual fire, the reinforced concrete beam is usually under load, so that most fire tests require loading the reinforced concrete beam. In addition, in order to realize different stress forms of the reinforced concrete beam, the loading modes of the reinforced concrete beam are different. For example, a common method for applying uniform load to reinforced concrete beams is heavy object stacking, i.e., placing sandbags or weights on the top surface of the beam; when the concentrated load is applied to the reinforced concrete beam, the reinforced concrete beam is divided into single-point loading and multi-point loading according to the number of loading points, the single-point loading can be realized by using a jack, and the multi-point loading can be realized by using the jack and the distribution beam in a matched manner. The loading mode brings several problems for measuring the deformation of the reinforced concrete beam under fire by using the LVDT: 1. if sand bags or weights are placed at the positions of the deformation measuring points of the reinforced concrete beam, the measuring heads of the LVDT cannot be placed on the measuring points smoothly; 2. if the section width of the reinforced concrete beam is smaller, and the measuring point position is just occupied by a jack or a distributing beam and other loading equipment, the space for placing the LVDT measuring head is too small, the measuring head is not firmly placed, the LVDT measuring head is easily separated from the top surface of the beam in the test process, and deformation measurement fails. Aiming at the problems that the LVDT measuring head cannot be placed on a measuring point smoothly due to stacking of the top surface of the reinforced concrete beam, or the space of the top surface of the reinforced concrete beam is narrow due to loading equipment, the measuring head is not firmly placed, and the like, two common solutions exist at present: the first method is to punch expansion bolts perpendicular to the top surface of the beam at the edges of the measuring points on the top surface of the beam, connect the measuring heads of the LVDT with the expansion bolts by iron wires, and when the beam is deformed, the expansion bolts move downwards along with the expansion bolts to drive the measuring heads of the LVDT to move downwards together. This approach has two disadvantages: firstly, after a fire test, the recovery of beam deformation in the cooling process is usually continuously measured, the deformation is vertical upwards, if the measuring rod of the LVDT is not parallel to the expansion bolt or the wire is too tightly bound to the measuring head of the LVDT at the moment, the measuring rod of the LVDT enters a metal shell of the LVDT to be blocked, so that the deformation measurement is influenced, and the measuring rod is bent by serious people to cause the damage of the LVDT; secondly, when the position of the measuring point on the top surface of the reinforced concrete beam is not provided with a space for punching expansion bolts, the method is not applicable. The second method is to punch expansion bolts perpendicular to the top surface of the beam at the edges of the measuring points on the top surface of the beam, then weld an iron tray at the upper ends of the expansion bolts, and place measuring heads of the LVDT on the iron tray. When the beam is deformed, the expansion bolts and the iron pallet move downwards simultaneously, and the measuring head of the LVDT on the pallet moves downwards together with the measuring rod. Meanwhile, when the deformation of the measuring beam is recovered in the cooling stage, the movement of the measuring rod of the LVDT, which is retracted into the metal shell of the measuring rod, is not blocked, so that the accuracy of the measuring result is ensured, and the LVDT is not easy to damage. The disadvantage of this method is still that it is not applicable when there is no space to make expansion bolts at the measuring point position on the top surface of the reinforced concrete beam.
In the existing fire test, the publication number is CN108061667A, the invention creates a method for realizing the fire resistance of the combined floor, and the technical scheme can test the fire resistance of the steel-concrete combined floor based on an ISO834 international standard heating curve, and comprises the steps of measuring the temperature of typical cross-section positions of concrete plates and steel beams in the steel-concrete combined floor under fire, measuring the support counter force of the steel-concrete combined floor under fire, and measuring the vertical deformation and lateral deformation of key positions of the concrete plates under fire. Firstly, a test object of a method for realizing the fire resistance of the combined floor is a steel-concrete combined floor, wherein the steel-concrete combined floor is a combined structure formed by a concrete slab at the upper part and a steel beam at the lower part, only the bottom surface and the steel beam of the concrete slab are on fire when an actual fire disaster occurs, and the side surface and the top surface of the concrete slab are not on fire; in order to simulate the fire scene, the steel-concrete combined floor system is only required to be directly buckled above a hearth of the fire test furnace when the fire test is carried out, and the fire in the fire test furnace is blocked by a concrete slab of the steel-concrete combined floor system; for the reinforced concrete beam, the bottom surface and the two side surfaces of the Liang Tongchang are on fire, the top surface is not on fire when an actual fire occurs, the fire scene of the reinforced concrete beam on three sides is simulated, and when a fire test is carried out, the beam is placed in a fire test furnace hearth, and flames are prevented from jumping out from the fire test furnace. Secondly, compared with the section width of the reinforced concrete beam, the steel-concrete combined floor has larger concrete slab size, namely, even if a uniformly distributed load application mode of placing a wood bracket and a sand bag in a partition grid and a partition grid on the top surface of the concrete slab is adopted, a displacement meter for measuring deformation is still placed on the top surface of the concrete slab in space, namely, a measuring head of the displacement meter can be firmly placed on the top surface of the concrete slab; aiming at different stress forms of the reinforced concrete beam, the load application modes are different: the common method for applying uniform load is heavy object piling, namely, placing sand bags or weights on the top surface of the beam; when the concentrated load is applied, the concentrated load is divided into single-point loading and multi-point loading according to the number of loading points, the single-point loading can be realized by using a jack, the multi-point loading can be realized by using the jack and a distribution beam in a matched manner, and if sand bags or weights are placed at the positions of deformation measuring points of the top surface of the reinforced concrete beam, the measuring heads of the LVDT can not be placed on the measuring points smoothly; if the section width of the reinforced concrete beam is smaller, and the measuring point position is just occupied by a jack or a distributing beam and other loading equipment, the space for placing the LVDT measuring head is too small, the measuring head is not firmly placed, and the LVDT measuring head is easily separated from the top surface of the beam in the test process, so that deformation measurement fails; therefore, compared with the deformation measurement of the steel-concrete composite floor system, the realization difficulty of the deformation measurement of the reinforced concrete beam is greater. Finally, in the implementation method of the testing device for fire resistance of the combined floor, a high-temperature special displacement meter is used, the price is high (2-3 times of the price of the displacement meter for normal temperature), and the highest use temperature of the high-temperature special displacement meter is about 200 ℃, so that the high-temperature special displacement meter is placed on the top surface of a concrete slab for a long time (the temperature can reach more than 200 ℃ generally), and the measurement accuracy of the high-temperature special displacement meter still drops or even burns out.
Therefore, it is needed to provide a differential transformer type displacement sensor probe supporting device and a construction and use method thereof, so as to solve the above-mentioned technical problems.
Disclosure of Invention
The invention aims to solve the problems that when the LVDT is used for measuring the deformation of a reinforced concrete beam in the existing fire test, an LVDT measuring head cannot be placed at a specified measuring point or is not firmly placed due to the fact that the width of the beam section is small or loading equipment is placed, and the like, and provides a differential transformer type displacement sensor measuring head supporting device and a construction and use method thereof. It should be understood that this summary is not an exhaustive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention.
The technical scheme of the invention is as follows:
differential transformer formula displacement sensor gauge head strutting arrangement, including first steel sheet, second steel sheet, supporting bar, fourth steel sheet and expansion bolts, be provided with expansion bolts on the first steel sheet, the second steel sheet is connected with the middle part of first steel sheet is perpendicular, and the middle part of second steel sheet is connected with supporting bar one end is perpendicular, and the supporting bar other end is connected with the middle part of fourth steel sheet is perpendicular, and the fourth steel sheet is located the upper portion of second steel sheet.
Preferably: the materials of the first steel plate, the second steel plate and the fourth steel plate are Q235FRC fireproof structural steel, the first steel plate, the second steel plate and the fourth steel plate are square steel plates with the same size, and the thickness of the square steel plates is 25mm-40mm.
Preferably: the number of the expansion bolts is four, and the four expansion bolts are uniformly distributed in a square shape.
Preferably: the supporting steel bar adopts HRB400 grade steel bar with the diameter of 30mm-36mm, and the model of the expansion bolt adopts M6 x 60.
The construction method of the measuring head supporting device of the differential transformer type displacement sensor comprises the following steps:
step one: determining the size of a square steel plate according to the height of the reinforced concrete beam;
step two: machining a hole for installing an expansion bolt on the first steel plate;
step three: attaching a first steel plate to the side surface corresponding to the deformation measuring point of the reinforced concrete beam, and marking the position of the hole on the first steel plate on the side surface of the reinforced concrete beam;
step four: machining a mounting hole at a mark of the reinforced concrete beam;
step five: attaching a first steel plate to the side surface of the reinforced concrete beam, aligning the holes on the first steel plate with the mounting holes of the reinforced concrete beam, sequentially installing expansion bolts into the aligned holes and the mounting holes, and fixing the first steel plate to the side surface of the reinforced concrete beam;
step six: welding the end part of the second steel plate on the central position of the first steel plate, and keeping the second steel plate vertical to the first steel plate;
step seven: determining the length of the support steel bar;
step eight: welding the supporting steel bars on the central position of the upper surface of the second steel plate, and keeping the supporting steel bars vertical to the second steel plate;
step nine: and welding the other end of the supporting steel bar on the central position of the lower surface of the fourth steel plate, and keeping the supporting steel bar vertical to the fourth steel plate.
Preferably: in the first step, the section height of the reinforced concrete beam is set as h 0 The side length of the square steel plate is h 0 2, the thickness of the square steel plate is 30mm;
step two, drilling a hole on each of four corner positions of the first steel plate by using an electric drill, wherein the diameter of the hole is 10mm, and the center of the hole is 25mm away from two adjacent edges of the first steel plate;
step four, drilling a mounting hole with the depth of 20mm and the diameter of 10mm at the marked position on the side surface of the reinforced concrete beam by utilizing an electric drill;
in the sixth step, the height of the welding seam is 6mm, and the length of the welding seam is the side length of the second steel plate;
in the seventh step, the length of the supporting steel bar is L 0 ，L 0 ＝h 0 /2+20cm；
And in the eighth step and the ninth step, the height of the welding seam is 6mm, the length of the welding seam is the diameter of the supporting steel bar, and the diameter of the supporting steel bar is 32mm.
The application method of the measuring head supporting device of the differential transformer type displacement sensor comprises the following steps:
step I: before a fire test starts, placing the reinforced concrete beam in a hearth of a fire test furnace;
step II: connecting a measuring head supporting device of the differential transformer type displacement sensor with the reinforced concrete beam;
step III: one side of aluminum silicate fire-resistant cotton is covered on the fire test furnace cover plate, and the other side of the aluminum silicate fire-resistant cotton is covered on the reinforced concrete beam so as to block flame in a gap between the fire test furnace cover plate and the reinforced concrete beam;
step IV: the upper end of the LVDT is fixed on a stationary reference object, and the LVDT measuring head is placed on a fourth steel plate.
Preferably: in the process of covering the aluminum silicate fireproof cotton, when the supporting steel bars are blocked, the aluminum silicate fireproof cotton can be covered in two sections, so that the supporting steel bars are clamped between the two sections of covered aluminum silicate fireproof cotton.
The invention has the following beneficial effects:
(1) When the supporting device of the LVDT measuring head is used for carrying out fire test of the reinforced concrete beam, the LVDT measuring head is supported, so that the LVDT measuring head is firmly placed on a supporting steel plate above the side face of the beam, and is not limited by a loading mode (a uniform load applying mode of stacking heavy objects such as sand bags or weights, a jack or a concentrated load applying mode used together with a distributing beam), and the problem that the LVDT measuring head is not firmly placed on the top face of the beam due to the fact that the section width of the reinforced concrete beam is small and a loading device is placed is solved;
(2) According to the supporting device for the LVDT measuring head, the LVDT measuring head is placed on the supporting steel plate above the side face of the reinforced concrete beam, and the LVDT measuring head and the measuring rod can move together with the deformation of the beam; the measuring head of the LVDT is always vertical to the supporting steel plate, so that when the deformation of the reinforced concrete beam is recovered after the fire disaster is measured, the measuring rod of the LVDT can freely retract into the metal shell of the LVDT without being blocked, thereby not only ensuring the accuracy of the measuring result, but also ensuring that the LVDT is not easy to damage;
(3) The supporting device of the LVDT measuring head realizes the extraction measurement of the deformation of the reinforced concrete beam in fire, and the measuring head of the LVDT is not directly arranged on the top surface of the beam (the temperature can reach more than 200 ℃ generally) but is arranged above the side surface of the beam, so that the problems of reduced measurement precision and even burnout caused by direct contact of the LVDT with a high-temperature environment are avoided;
(4) The supporting device of the LVDT measuring head fully considers the material of the reinforced concrete beam, and the drilling and welding means are all traditional construction processes, so the device has the advantages of simple construction process, convenient operation and use, low cost and strong economic applicability.
Drawings
FIG. 1 is a front view of a differential transformer type displacement sensor probe support device;
FIG. 2 is a left side view of FIG. 1;
fig. 3 is a diagram showing the installation and use of the probe support device of the differential transformer type displacement sensor.
In the figure: 1-first steel plate, 2-second steel plate, 3-supporting steel bar, 4-fourth steel plate, 5-expansion bolt, 6-reinforced concrete beam, 7-fire test furnace wallboard, 8-fire test furnace cover plate, 9-aluminum silicate fireproof cotton and 10-LVDT.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the present invention is described below by means of specific embodiments shown in the accompanying drawings. It should be understood that the description is only illustrative and is not intended to limit the scope of the invention. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the present invention.
The first embodiment is as follows: referring to fig. 1-2, a differential transformer type displacement sensor probe supporting device of the present embodiment is described, and the differential transformer type displacement sensor probe supporting device comprises a first steel plate 1, a second steel plate 2, supporting steel bars 3, a fourth steel plate 4 and expansion bolts 5, wherein the expansion bolts 5 are arranged on the first steel plate 1, the second steel plate 2 is vertically and fixedly connected with the middle part of the first steel plate 1, the middle part of the second steel plate 2 is vertically and fixedly connected with one end of the supporting steel bars 3, the other end of the supporting steel bars 3 is vertically and fixedly connected with the middle part of the fourth steel plate 4, and the fourth steel plate 4 is positioned on the upper part of the second steel plate 2; the invention is a supporting device which is not influenced by a loading mode, is not influenced by the size of the top surface space of the reinforced concrete beam, is firm in placement of the LVDT measuring head and is not easy to damage.
The second embodiment is as follows: referring to fig. 1 to 2, a description will be given of a probe supporting device for a differential transformer type displacement sensor according to the present embodiment, wherein the first steel plate 1, the second steel plate 2, and the fourth steel plate 4 are made of Q235FRC refractory structural steel, the first steel plate 1, the second steel plate 2, and the fourth steel plate 4 are square steel plates having the same dimensions, and the thickness of the square steel plates is 25mm to 40mm.
And a third specific embodiment: referring to fig. 1 to 2, the differential transformer type displacement sensor probe supporting device of the present embodiment is described, in which the number of expansion bolts 5 is four, and four expansion bolts 5 are arranged uniformly in a square shape.
The specific embodiment IV is as follows: referring to fig. 1-2, a description is given of the differential transformer type displacement sensor probe supporting device of the present embodiment, wherein the supporting steel bar 3 adopts HRB400 grade steel bars with diameters of 30mm-36mm, and the expansion bolts 5 adopt M6 x 60; the device fully considers the materials of the reinforced concrete beam, and the drilling and welding means are all traditional construction processes, so the device has the advantages of simple construction process, convenient operation and use, low cost, strong economic applicability and high strength.
Fifth embodiment: the construction method of the differential transformer type displacement sensor probe supporting device according to the present embodiment will be described with reference to fig. 1 to 3, and the differential transformer type displacement sensor probe supporting device is adopted, and includes the steps of:
step one: determining the size of the square steel plate according to the section height of the reinforced concrete beam 6;
step two: machining a hole for installing an expansion bolt 5 on the first steel plate 1;
step three: attaching the first steel plate 1 to the side surface corresponding to the deformation measuring point of the reinforced concrete beam 6, aligning the center of the side surface of the reinforced concrete beam 6 corresponding to the deformation measuring point with the center of the first steel plate 1, and marking the position of the hole on the first steel plate 1 on the side surface of the reinforced concrete beam 6;
step four: machining a mounting hole at a mark of the reinforced concrete beam 6;
step five: attaching a first steel plate 1 to the side surface of a reinforced concrete beam 6, aligning holes on the first steel plate 1 with mounting holes of the reinforced concrete beam 6, sequentially installing expansion bolts 5 into the aligned holes and the mounting holes, screwing nuts, and fixing the first steel plate 1 to the side surface of the reinforced concrete beam 6;
step six: welding an end portion of the second steel plate 2 to a central position of the first steel plate 1, and keeping the second steel plate 2 perpendicular to the first steel plate 1;
step seven: determining the length of the support steel bar 3;
step eight: welding the supporting steel bars 3 on the central position of the upper surface of the second steel plate 2, and keeping the supporting steel bars 3 vertical to the second steel plate 2;
step nine: welding the other end of the supporting steel bar 3 on the central position of the lower surface of the fourth steel plate 4, and keeping the supporting steel bar 3 vertical to the fourth steel plate 4; the manufacturing and mounting of the supporting device of the measuring head of the differential transformer type displacement sensor (LVDT) for the fire test of the reinforced concrete beam are completed; according to the invention, when a fire test of the reinforced concrete beam is carried out, the measuring head of the LVDT is supported, namely, the extraction measurement of the deformation of the reinforced concrete beam under the fire is realized; the device ensures that the measuring head of the LVDT is firmly placed on the supporting steel plate (fourth steel plate) above the side surface of the beam (reinforced concrete beam 6), so that the device is not limited by a loading mode (a uniform load applying mode of stacking heavy objects such as sand bags or weights, a jack or a concentrated load applying mode matched with a distribution beam for use together), and solves the problem that the placing of the measuring head of the LVDT or the measuring head of the LVDT is not firm because of the small section width of the reinforced concrete beam and the insufficient space on the top surface of the beam caused by the placing of loading equipment.
Specific embodiment six: referring to fig. 1 to 3, a description will be given of a construction method of a probe supporting device for a differential transformer type displacement sensor according to the present embodiment, wherein in the first step, a reinforced concrete beam 6 is provided with a cross-sectional height h 0 The side length of the square steel plate is h 0 2, the thickness of the square steel plate is 30mm;
in the second step, drilling a hole on each of four corner positions of the first steel plate 1 by using an electric drill, wherein the diameter of the drilled hole is 10mm, and the center of the drilled hole is 25mm away from two adjacent sides of the first steel plate 1;
step four, drilling a mounting hole with the depth of 20mm and the diameter of 10mm at the marked position on the side surface of the reinforced concrete beam 6 by utilizing an electric drill;
in the sixth step, the height of the welding seam is 6mm, and the length of the welding seam is the side length of the second steel plate 2;
in the seventh step, the length of the supporting steel bar 3 is L 0 ，L 0 ＝h 0 /2+20cm；
In the eighth and ninth steps, the height of the welding seam is 6mm, the length of the welding seam is the diameter of the supporting steel bar 3, and the diameter of the supporting steel bar 3 is 32mm.
Seventh embodiment: referring to fig. 1 to 3, a description will be given of a method for using a differential transformer type displacement sensor probe supporting device according to the present embodiment, based on the construction method of the differential transformer type displacement sensor probe supporting device, a fire test furnace cover plate 8 is provided on a fire test furnace wall plate 7, a fire test furnace chamber is formed inside the fire test furnace wall plate 7 and the fire test furnace cover plate 8, and an aluminum silicate refractory cotton 9 is provided on an upper portion of the fire test furnace cover plate 8, comprising the steps of:
step I: before a fire test starts, placing the reinforced concrete beam 6 in a hearth of a fire test furnace;
step II: the construction method of the differential transformer type displacement sensor measuring head supporting device is adopted, and the differential transformer type displacement sensor measuring head supporting device is connected with the reinforced concrete beam 6;
step III: one side of aluminum silicate fire-resistant cotton 9 is covered on the fire test furnace cover plate 8, and the other side of the aluminum silicate fire-resistant cotton 9 is covered on the reinforced concrete beam 6 so as to block flame in a gap between the fire test furnace cover plate 8 and the reinforced concrete beam 6;
step IV: fixing the upper end of the LVDT10 on a stationary reference object, and placing a measuring head of the LVDT10 on the fourth steel plate 4, wherein the LVDT is a differential transformer type displacement sensor; the device of the invention enables the measuring head of the LVDT to be placed on the steel plate above the side surface of the reinforced concrete beam, and the measuring head and the measuring rod of the LVDT can move together with the deformation of the beam; and because the measuring head of the LVDT is always vertical to the supporting steel plate (the fourth steel plate or the second steel plate), when the deformation of the reinforced concrete beam is recovered after the fire disaster is measured, the measuring rod of the LVDT can freely retract into the metal shell of the LVDT without being blocked, thereby not only ensuring the accuracy of the measuring result, but also ensuring that the LVDT is not easy to damage.
Eighth embodiment: 1-3, in the process of covering aluminum silicate fireproof cotton 9, when the supporting steel bar 3 is blocked, the aluminum silicate fireproof cotton 9 can be covered in two sections, so that the supporting steel bar 3 is clamped between the two sections of covered aluminum silicate fireproof cotton 9, the setting is convenient, and when a fire test is carried out, a fire scene of three sides of a reinforced concrete beam is simulated, and a fire test furnace cover plate and the aluminum silicate fireproof cotton are used for covering to prevent flame from jumping out of the fire test furnace, thereby ensuring the reliability of a test result and the safety of the test process; the device of the invention realizes the extraction measurement of the deformation of the reinforced concrete beam in fire, the measuring head of the LVDT is not directly arranged on the top surface of the beam (the temperature can reach more than 200 ℃ generally), but is arranged above the side surface of the beam, the problem that the LVDT is directly contacted with the high-temperature environment to cause the reduction of measurement precision and even the burning is avoided, and the supporting device of the LVDT measuring head of the invention is used for the deformation measurement in fire by using the LVDT at normal temperature, thus the displacement meter is cheaper than a special displacement meter at high temperature, the test cost is reduced, and the economic applicability is stronger.
It should be noted that, in the above embodiments, as long as the technical solutions that are not contradictory can be arranged and combined, those skilled in the art can exhaust all the possibilities according to the mathematical knowledge of the arrangement and combination, so the present invention does not describe the technical solutions after the arrangement and combination one by one, but should be understood that the technical solutions after the arrangement and combination have been disclosed by the present invention.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. Differential transformer formula displacement sensor gauge head strutting arrangement, its characterized in that: including first steel sheet (1), second steel sheet (2), supporting reinforcement (3), fourth steel sheet (4) and expansion bolts (5), be provided with expansion bolts (5) on first steel sheet (1), second steel sheet (2) are connected perpendicularly with the middle part of first steel sheet (1), and the middle part of second steel sheet (2) is connected perpendicularly with supporting reinforcement (3) one end, and supporting reinforcement (3) other end is connected perpendicularly with the middle part of fourth steel sheet (4), and fourth steel sheet (4) are located the upper portion of second steel sheet (2).
2. The differential transformer type displacement sensor probe supporting device according to claim 1, wherein: the materials of the first steel plate (1), the second steel plate (2) and the fourth steel plate (4) are Q235FRC fireproof structural steel, the first steel plate (1), the second steel plate (2) and the fourth steel plate (4) are square steel plates with the same size, and the thickness of the square steel plates is 25mm-40mm.
3. The differential transformer type displacement sensor probe supporting device according to claim 2, wherein: the number of the expansion bolts (5) is four, and the four expansion bolts (5) are uniformly arranged in a square shape.
4. A differential transformer type displacement sensor probe supporting device according to any one of claims 1 to 3, wherein: the supporting steel bar (3) adopts HRB400 grade steel bar with the diameter of 30mm-36mm, and the model of the expansion bolt (5) adopts M6 x 60.
5. The construction method of the measuring head supporting device of the differential transformer type displacement sensor is characterized by comprising the following steps of: a differential transformer type displacement sensor probe supporting device according to any one of claims 1 to 4, comprising the steps of:
step one: determining the size of the square steel plate according to the height of the reinforced concrete beam (6);
step two: machining a hole for installing an expansion bolt (5) on a first steel plate (1);
step three: attaching a first steel plate (1) to the side surface corresponding to the deformation measuring point of the reinforced concrete beam (6), and marking the position of the upper hole of the first steel plate (1) on the side surface of the reinforced concrete beam (6);
step four: processing a mounting hole at a mark of the reinforced concrete beam (6);
step five: attaching a first steel plate (1) to the side surface of a reinforced concrete beam (6), aligning holes on the first steel plate (1) with mounting holes of the reinforced concrete beam (6), sequentially installing expansion bolts (5) into the aligned holes and the mounting holes, and fixing the first steel plate (1) to the side surface of the reinforced concrete beam (6);
step six: welding the end part of the second steel plate (2) on the central position of the first steel plate (1), and keeping the second steel plate (2) vertical to the first steel plate (1);
step seven: determining the length of the supporting steel bar (3);
step eight: welding the supporting steel bar (3) on the central position of the upper surface of the second steel plate (2), and keeping the supporting steel bar (3) vertical to the second steel plate (2);
step nine: and welding the other end of the supporting steel bar (3) on the central position of the lower surface of the fourth steel plate (4), and keeping the supporting steel bar (3) vertical to the fourth steel plate (4).
6. The construction method of the differential transformer type displacement sensor probe supporting device according to claim 5, wherein: in the first step, the section height of the reinforced concrete beam (6) is set as h 0 The side length of the square steel plate is h 0 2, the thickness of the square steel plate is 30mm;
step two, drilling a hole on each of four corner positions of the first steel plate (1) by using an electric drill, wherein the diameter of the hole is 10mm, and the center of the hole is 25mm away from two sides of the first steel plate (1);
step four, drilling a mounting hole with the depth of 20mm and the diameter of 10mm at the marked position on the side surface of the reinforced concrete beam (6) by utilizing an electric drill;
in the sixth step, the height of the welding seam is 6mm, and the length of the welding seam is the side length of the second steel plate (2);
in the seventh step, the length of the supporting steel bar (3) is L 0 ，L 0 ＝h 0 /2+20cm；
And in the eighth step and the ninth step, the height of the welding seam is 6mm, the length of the welding seam is the diameter of the supporting steel bar (3), and the diameter of the supporting steel bar (3) is 32mm.
7. The application method of the measuring head supporting device of the differential transformer type displacement sensor is characterized by comprising the following steps of: a construction method based on the differential transformer type displacement sensor probe supporting device according to any one of claims 5 to 6, comprising the steps of:
step I: before a fire test starts, placing a reinforced concrete beam (6) in a hearth of a fire test furnace;
step II: connecting a measuring head supporting device of the differential transformer type displacement sensor with the reinforced concrete beam (6);
step III: one side of aluminum silicate fireproof cotton (9) is covered on the fire test furnace cover plate (8), and the other side of the aluminum silicate fireproof cotton (9) is covered on the reinforced concrete beam (6) so as to block flame in a gap between the fire test furnace cover plate (8) and the reinforced concrete beam (6);
step IV: the upper end of the LVDT (10) is fixed on a stationary reference object, and the measuring head of the LVDT (10) is placed on the fourth steel plate (4).
8. The method of using a differential transformer type displacement sensor probe support device according to claim 7, wherein: in the process of paving the aluminum silicate fireproof cotton (9), when encountering the obstruction of the supporting steel bar (3), the aluminum silicate fireproof cotton (9) can be paved in two sections, so that the supporting steel bar (3) is clamped between the two sections of the aluminum silicate fireproof cotton (9).
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| CN202311303526.2A CN117516610A (en) | 2023-10-10 | 2023-10-10 | Differential transformer type displacement sensor measuring head supporting device and construction and use methods thereof |
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| CN202311303526.2A CN117516610A (en) | 2023-10-10 | 2023-10-10 | Differential transformer type displacement sensor measuring head supporting device and construction and use methods thereof |
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