JP2005114375A - Method for detecting endurance limit of temporary construction member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detecting method which easily detects an endurance limit of a construction member constructing a structure employing steel products such as a temporary bridge, a temporary multilevel parking structure or the like. <P>SOLUTION: An indicator 4 which visually indicates approximation of the endurance limit by using cracks, is arranged at a section which is considered as a fatiguable portion of the temporary construction member being used for constructing a truss body 1, a base plate or the like. The fatigue limit of the construction member is detected by using the indicator 4, thereby easily carrying out discarding and restoring the respective construction members, in accordance with degrees of their damages. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a detection method for detecting a fatigue limit of a constituent member constituting a structure using a steel material such as a temporary bridge or a temporary establishment parking lot.

Conventionally, temporary bridges have been built to secure detours during bridge restoration work and bridge replacement work.
Each component that constructs this temporary bridge is generally processed using steel materials such as H steel, lip steel, and steel plate so that they can be used in various construction sites. Is. For example, as an example of such a structural member, there is a lateral coupling member configured to be fastened and disassembled by a bolt (see, for example, Patent Document 1).

In addition, there is a temporary truss bridge as one of the types of temporary bridges, and there is a type in which the truss portion can be modularized and connected (for example, see Patent Document 2).
In addition to the temporary bridge described above, there is a multilevel parking lot constructed using steel (for example, Patent Document 3).

Japanese Patent Laid-Open No. 08-53812 (page 3, FIG. 4) JP 2002-38416 A (Page 4, FIG. 1) JP-A-7-293020 (2nd page, FIG. 1)

  The former structural member for the temporary bridge is, of course, repeated over and over every time the temporary bridge is temporarily constructed. The degree of fatigue is different for each component due to various causes such as a difference in amount (the number of times of load is different), a temporary number of days, and the like.

  In addition, the latter multistory parking lot is sometimes used as a temporary parking lot because multiple units can be parked at construction sites of large buildings, etc. Since the vehicle is also parked, damage is often caused to each structural member such as a beam and a pillar portion constituting the multi-story parking lot. In addition, the parking position (number of parkings) is often offset, and therefore, the structural members constituting the multi-story parking lot as well as the above-described temporary bridge structural members have different degrees of fatigue for each structural member.

  Under such circumstances, it is very preferable to manage each component according to its degree of fatigue, because it is possible to discard or repair the member according to the degree of damage of each component. As near as impossible.

  Therefore, it is the present condition that the degree of fatigue of individual structural members constituting a structural body such as a temporary bridge or a multistory parking lot is unknown. Therefore, from the viewpoint of preventing accidents, although regular patrols are carried out, it cannot be said that the situation is favorable for safety management.

  Then, an object of this invention is to provide the detection method which can detect easily the fatigue limit of the structural member which comprises structures using steel materials, such as a temporary bridge and a temporary establishment body parking lot.

In order to solve the above problems, the fatigue limit detection method for a temporary component according to the present invention employs the following technical means.
In other words, the fatigue limit detection method for a temporary component according to claim 1 is such that the fatigue limit of the component is close to a portion that is expected to be subject to fatigue of the component that constitutes the structure using steel. It is characterized by providing an indicator that can be visually recognized with a crack, and detecting the fatigue limit of the constituent member with the indicator.
According to a second aspect of the present invention, there is provided a fatigue limit detection method for a temporary constituent member according to the first aspect, wherein the constituent member is formed by forming a steel material into a substantially mountain-shaped frame and temporarily setting the steel material in an inclined shape. A vertical connecting surface for connecting the members from the base portion is a truss body provided so as to extend through a plate-like member having an upper surface formed with a concave curved surface.
According to a third aspect of the present invention, there is provided a fatigue limit detection method for a temporary constituent member according to the first aspect, wherein the constituent member is a floor slab formed in a substantially box shape.
According to a fourth aspect of the present invention, there is provided the fatigue limit detection method for a temporary constituent member according to any one of the first to third aspects, wherein the indicator is formed in a substantially plate shape or a substantially rod shape, and a stress concentration portion of the constituent member. It is attached through an attachment member fixed in the vicinity.

  According to the present invention, an indicator that makes it possible to visually recognize with a crack that the fatigue limit of the constituent member has been approached is provided at a site that is expected to be subject to fatigue of the constituent member that constitutes the structure using the steel material. In addition, since the fatigue limit of the constituent member is detected by the indicator, the management of each constituent member in accordance with the degree of fatigue such that the member can be easily discarded or repaired according to the degree of damage of each constituent member. Can do.

  Next, an embodiment of the present invention will be described with reference to FIGS. The fatigue limit detection method in the temporary component according to the present embodiment is an example applied to a truss body, a floor slab, and a girder part of the temporary parking lot that constitute a temporary bridge or a temporary parking lot. In the figure, reference numeral 1 denotes a truss body, reference numeral 2 denotes a floor slab, reference numeral 3 denotes a girder around the temporary parking lot, and reference numeral 4 denotes an indicator.

  First, the case where a temporary structural member is the truss body 1 is demonstrated based on FIGS.

  As shown in FIGS. 1 and 2, the truss body 1 is formed in a frame shape with an H-shaped steel 11 and is welded with a mounting plate 12 facing the top of the frame so as to sandwich the top. Has been. The mounting plate 12 is provided with bolt insertion holes (not shown) at a predetermined interval, and runs laterally in a gap (in the depth direction in FIG. 1) formed between the mounting plates 12. The string material 13 is inserted and bolted.

  Further, each base portion of the pair of H-shaped steels 11 installed in an inclined manner has a vertical connecting surface via a plate-like member 14 whose upper surface is formed with a concave curved surface so as to be continuous with the H-shaped steel 11. 11a is provided so that it may overhang. The connection surface 11a is provided with bolt insertion holes (not shown) at a predetermined interval, and can be continuously provided by bolting the truss bodies 1 to each other.

  When the truss body 1 is constructed as a temporary bridge by connecting the truss bodies 1 in series, the protruding plate-like member 14 is cracked because it is inferior in strength compared to the framed H-shaped steel 11 in particular. Or easily destroyed. Therefore, as described above, the upper surface of the plate-like member 14 is formed with a concave curved surface to improve the mechanical strength.

  An indicator 4 having a fatigue characteristic clarified in advance by an experiment (having a specific SN curve) is provided in a portion of the truss body 1 that is likely to be fatigued (for example, H-shaped steel 11). In this experiment, the SN curve can be easily grasped by attaching a strain gauge to the indicator 4 and measuring the fatigue stress.

  Here, this SN curve can be graphed with the stress (S = trees) generated in the test material in the fatigue test on the vertical axis and the number of repetitions until the material breaks (N = number) on the horizontal axis. This means that the fatigue strength can be illustrated.

  In addition, as shown in the figure, the indicator 4 is provided at the base of the H-shaped steel 11 where stress is concentrated, as shown in the figure, in which a mounting hole 41 is provided at both ends and the middle part is cut into a constricted shape so as to be narrow. The indicator 4 is pivotally attached to the projecting piece (attachment member) 15 with a pin 42 through an attachment hole 41.

  Further, the indicator 4 is provided with a scale 43 extending in the longitudinal direction at an intermediate portion notched in a constricted shape, so that the progress distance of the crack can be easily visually confirmed.

  The fatigue limit detection method performed using the truss body 1 configured as described above is the indicator described above when constructing a temporary bridge or a temporary parking lot or during patrol of the constructed temporary bridge or temporary parking lot. Check 4 visually.

  At that time, as shown in FIG. 3A, when the indicator 4 does not change, it can be visually confirmed that the truss body 1 is in a safe state, and as shown in FIG. When a crack is formed in the middle part notched in the constricted shape, it indicates that the truss body 1 is approaching the fatigue limit. Further, as shown in FIG. 3C, when the indicator 4 is broken, The truss body 1 indicates the fatigue limit, and the fatigue state of the truss body 1 can be easily visually observed. As described above, when cracks or breaks are observed in the indicator 4, the truss body 1 is discarded or reinforced and repaired.

  That is, even if the degree of fatigue differs for each individual truss body 1, when the truss body 1 approaches the fatigue limit, the indicator 4 is cracked or broken before the truss body 1. The fatigue life can be easily visually observed.

  Next, the case where the temporary component is the floor slab 2 will be described with reference to FIGS. 4 and 5. In addition, the same structure as the structure demonstrated by said truss body 1 attaches | subjects the same code | symbol, and abbreviate | omits description.

  In the floor slab 2, a rectangular steel plate 22 is welded on a C-shaped steel 21 arranged in parallel so that the opening portion faces upward at a predetermined interval, and an indicator having the same configuration as the indicator 4 exemplified above. 4 is suspended via a projecting piece 15 provided on the lower surface of the center of the steel plate edge located in the longitudinal direction of the C-shaped steel 21. The hanging position of the indicator 4 is a portion that is expected to be easily fatigued in the floor slab 2.

  And this floor slab 2 is supported by screwing the longitudinal direction both ends of the C-shaped steel 21 to the chord material which consists of the H-shaped steel 11 which comprises a temporary bridge and a temporary parking lot.

  As the floor slab 2 is supported at both ends by the string material in this way, the stress due to the load applied from above is maximized at the central portion, and by providing the indicator 4 at such a portion, as in the above, the temporary bridge When constructing a temporary parking lot or during patrol of a constructed temporary bridge or temporary parking lot, the above-mentioned indicator 4 is visually checked to detect the degree of fatigue.

  Next, the case where the temporary component is around the girder of the temporary parking lot will be described with reference to FIG. In addition, the same structure as the structure demonstrated by said truss body 1 attaches | subjects the same code | symbol, and abbreviate | omits description.

  The girder part 3 of the temporary parking lot is framed in a T-shape with a main girder member 31 that is a beam and a column member 32 that is a column, and in the vicinity of the corner between the main girder member 31 and the column member 32. A cane member 33 that supports the main girder member 31 and the column member 32 is constructed so as to be inclined, and the wobble in the vertical direction acts on the cane member 33 and stress is concentrated. The indicator 4 is erected so as to be parallel to the cane member 33 inside (or outside). It should be noted that the installation position of the indicator 4 is a part that is expected to be subject to fatigue in the girder part 3.

  Thus, by providing the indicator 4 in such a part, when the temporary parking lot is constructed or when the constructed temporary parking lot is patroled, the indicator 4 is visually confirmed, as described above. The degree of fatigue around 3 is detected.

  As mentioned above, although the fatigue limit detection method in the temporary structural member concerning this Embodiment was demonstrated, embodiment mentioned above shows an example of the suitable embodiment of this invention, and this invention is limited to it. However, various modifications may be made without departing from the scope of the invention.

It is a front view of the truss body using the fatigue limit detection method concerning this embodiment. It is an enlarged view of the principal part in FIG. It is a front view of the indicator which changes with stress, (a) The truss body (temporary constituent member) shows a safe state (b) The truss body (temporary constituent member) shows that the fatigue limit is approached (c) Indicates that the truss body (temporary component) is at the fatigue limit It is a perspective view of the floor slab using the fatigue limit detection method concerning this Embodiment. It is a disassembled perspective view in the principal part of a floor slab. It is a front view around the girder part of the temporary parking lot using the fatigue limit detection method concerning this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Truss body 11 H-shape steel 12 Mounting plate 13 String material 14 Plate-shaped member 15 Protrusion 11a Connection surface 2 Floor slab 21 C-shape steel 22 Steel plate 3 Around the girder part of a temporary parking lot 31 Main girder material 32 Prop material 33 Wand material 4 Indicator 41 Mounting hole 42 Pin 43 Scale

Claims (4)

  An indicator that makes it possible to visually recognize that the fatigue limit of the constituent member is approached by a crack is provided at a portion that is expected to be subject to fatigue of the constituent member that constitutes the structure using the steel material. A method for detecting a fatigue limit in a temporary component, characterized by detecting a fatigue limit of the component.   The structural member is formed by forming a steel frame into a substantially mountain-shaped frame, and a vertical connection surface for connecting the members from each base portion of a pair of the steel materials temporarily installed in an inclined shape has a concave curved upper surface. The fatigue limit detection method for a temporary component member according to claim 1, wherein the truss body is provided so as to extend through a plate-shaped member having a surface formed thereon.   2. The fatigue limit detection method for a temporary component according to claim 1, wherein the component is a floor slab formed in a substantially box shape.   The said indicator is attached through the attachment member fixed to the vicinity of the site | part where the stress concentration of the said structural member is formed while being substantially plate-shaped or substantially rod-shaped. The fatigue limit detection method in the temporary component of any of these.

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