JPS62110136A - Method for inspecting change state of floor panel concrete - Google Patents

Abstract

PURPOSE:To make it possible to inspect a change state efficiently and safely with high accuracy, by charging a positive film, to which the locating point from a surface to be inspected was set, in an analytical chart forming machine to form the change state distribution drawing of a concrete surface. CONSTITUTION:A measuring camera 4 arranged on the ground under the floor panel concrete of the bridge supported at a high position by bridge piers 1 to photograph the back surface of the floor concrete 2. An illumination apparatus 5 such as a stroboscope is arranged to the time of photographing to illuminate the back surface of the concrete 2. Further, in photographing, a measuring camera having a large focus distance with respect to a photographing distance is used to perform photographing on the basis of locating points based on the vertical girder, transverse girder and reinforcing girder etc. of the bridge. The photographed film is developed and, further, a positive film is formed from the obtained negative film and applied to an analytical chart forming machine to perform location to obtain a change state distribution drawing. By this method, the inspection of a change state can be efficiently and perfectly performed with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for inspecting deformation of concrete floor slabs, etc.

[Conventional technology] In recent years, the degree of fatigue has been measured by inspecting the deformation of concrete slabs of aging bridges, etc. (mainly the presence or absence of cracks, their size, peeling, exposed reinforcing bars, and free lime). Various things are being done.

Conventionally, deformation of concrete bridge deck slabs has been inspected by installing scaffolding on the back side of the concrete bridge slab, allowing inspection workers to approach the object to be inspected, visually inspect it, and record it. Ta.

[Problems to be solved by the invention] However, in the above conventional method, the work of assembling and dismantling scaffolding etc. is extremely difficult, and inspection requires time and effort.
Working at heights is difficult and dangerous, and visual inspections may overlook thin cracks or make recording errors.Furthermore, visual inspections may result in individual differences in inspection results, including the size and distribution of cracks. There were problems with this.

The present invention focuses on the above-mentioned conventional problems, and aims to provide a method for inspecting deformation of a concrete surface with high precision and safety from a remote location without requiring installation of scaffolding or the like. It is said that

[Means for solving the problems] The present invention attempts to solve the above technical problems, and
Determine the scale and control point according to the shadow distance to the concrete surface to be inspected, and measure the concrete surface with the measurement camera.
＠Make positive film from the negatives that have been shadowed, removed, and developed.
Relating to a deformation inspection method for floor slab concrete, etc., characterized in that the positive film on which control points from the surface to be inspected are set is fed into an analytical plotting machine to create a deformation distribution map of the concrete surface. It is something.

[Function] Therefore, in the present invention, the concrete surface is imitated from a position far away from the concrete surface using a measuring camera, and the deformation of the concrete surface is detected based on the shadow information. inspection can be performed easily, safely, accurately, and efficiently from a remote location.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the present invention, in which a measuring camera 4 is installed upward on the lower ground 3 of a concrete deck 2 of a bridge supported at a high position by a bridge pier 1, and Mirror the back side of 2. In addition, since the underside of the bridge is dark even during the day, lighting devices such as strobes 5 must be used during the above removal.
is installed to illuminate the back side of concrete floor slab 2.

When scanning, as shown in Figures 2 and 3, a measuring camera with a focal length F larger than the mirror distance is used to increase the accuracy of the tracing, and as shown in Figure 4 ( D (n
), the projection A and the projection B are the longitudinal girder 6 of the bridge, for example, so that a stereo photograph of 60% wrap C can be obtained.
Surveying will be carried out based on the reference points of the cross beams 7, reinforcing beams 8, etc. (see Figure 5).

The imaged film is developed, a positive film is made from the negative, and it is oriented using an analytical plotting machine to obtain a deformation distribution map as shown in FIG. The analysis plotter is adjusted to the state of deflection (tilt) when it is imaged and set at the control point from the surface to be inspected so that it can be viewed stereoscopically. There is a scalpel mark in the center of the field of view of the analytical plotter, and by keeping this in close contact with and tracking the area to be determined, such as a crack, it is possible to draw with a pen linked to the scalpel mark. The scale of the distribution map can be plotted using the value set on the analytical plotter.

According to the deformation distribution map shown in Figure 5 obtained by the above analytical plotting machine, it is possible to accurately read the width, size and position of cracks, the position and range of free lime and flaking, the position of exposed reinforcing bars, etc. . In the above, what requires particular attention in terms of bridge management are the cracks with limestone, which are thought to have been caused by the cracks reaching the surface and allowing rainwater to seep in.

Examples of tests actually conducted are shown below.

Hara Cell Brad MK-70 was used as the measurement camera, and a lens of F: 60 mm was attached to the camera, and the 60%
In order to obtain stereo photographs of the lap, continuous imaging was carried out at control points necessary for the analysis plotter, such as longitudinal girder 6, transverse girder 7, reinforcing girder 8, etc.

At this time, the distance between the concrete floor slab 2 and the measurement camera 4 was as short as 3 m, so the distance of the stone being fed by the lens was read and adjusted during plotting.

Therefore, the focal length is 60mm (oo) +1.2~1.39=61.2~
The size of the camera was 61.39m1ll, which resulted in a somewhat narrower angle of view, resulting in one photo covering an area of 2.54m x 2.54m.

A correct virtual image space was reproduced by an analytical plotter using a positive film based on the control points.

For the following items, draw a 1/20 scale orthogonal image, set 56 crack measurement points in the bronze statue, and set the coordinates of the crack width as M and T.

It was recorded on (!1ki tape).

Depiction items 1. crackle 2. Peeling 3. Reinforcement exposed 4. Free lime Regarding the crack width, (b) Method using diagrammatic measurement (b) Interpretation based on class classification We investigated two types.

In the diagrammatic measurement method, arbitrary coordinates are set from the object to be inspected, and the coordinates (for 2 points) of measurement points are M and T.

automatically recorded.

For interpretation by class classification, prepare a photo enlarged 4 times,
A photographic reproduction of a group of lines drawn at a constant width corresponding to the photographic scale was used, and by visually comparing and contrasting this, the crack width was deciphered for each class classification. .

FIG. 5 shows the inspection results of the deformation distribution plotted using an analytical plotter at a scale of 1/20.

1. Cracks (represented by classifying the width) 2. Free lime (Ca, main area surrounded by dotted lines) 3. Peeling 2ft (D, same as above) 4. Reinforcement exposed shape is expressed as is) Regarding the crack situation: , which corresponded well with the results of the visual inspection of the specimen that had already been carried out, and it was confirmed that the cracks were developing in the direction of cutting the slab concrete.

The types of deformation are: 1. ．． 2. The main thing is 4. was present in one location, but this is not due to deterioration and is thought to have existed from the time of construction. For 3°, there was no original peeling at all, and a pattern with discoloration and roughness was adopted.

The measurement capability of the analytical plotter was significantly 0.01 mm, and the minimum value of the measurement results was 0.15 mm. This value can be said to be sufficiently significant in terms of machine accuracy. Significantly 0.15mm
is 0.003 mm on a photograph with a scale of 1150, which is the photographic particle size (2 um).

In Figure 2, the shooting scale is F: Focal length L: Shooting distance W: Significant cracking d: Width of crack elephant It is.

Looking at the scales Δ, B, C, and D in FIG. 3, the measurement capabilities are as shown in Table 1.

Table 1 Furthermore, looking at the photographing distance LL = lens focal length F, L = 5 m - + F = 1100 mm1 =
10 −+ F=25On+m1=30m −+
F=500mm, and the shooting distance is lyl a
X, 30m is the limit.

In addition, in the case of visual interpretation, the photograph was enlarged 4 times and worked at a scale of 1/12°5, and the visual limit was 0.02 mm.
'C- Yes, it can be said that the limit is significantly 0.25mm.

Therefore, in actual work, if the distance ``Oka-kage'' differs depending on the field conditions, it is necessary to select the focal length F according to FIG. 3 in order to maintain the scale.

In the above, a case has been described in which 18 shadows are taken from the ground, but if photographing from the ground is not possible, various methods such as those shown in FIG. 6 can be adopted.

That is, as shown in (c) in Fig. 6, the camera 4 for measurement is taken obliquely using the abutment 9, or when the water depth is shallow, as shown in (B), a storage support 10 made of an iron pipe or the like is erected in the water. When the water depth is deep, the measurement camera 4 is supported by a floating body 11 such as an assembled raft or ship and an anti-vibration camera mount 12, or the measurement camera 4 is attached to a sonde (balloon) 13. 4 and float it to the surface,
This can be done by a method such as taking a photo while standing still on the back side of the concrete floor slab 2.

Alternatively, as shown in FIG. 7, a camera support plate 14 is attached to the top surface of the balloon 13 to support the measurement camera 4, and the floor slab concrete 2 is supported by, for example, three-point support columns 15. Try to keep the shooting distance to the surface constant. In this way, it is possible to take pictures at a constant shooting distance even at a very distant position.

It should be noted that the present invention is not limited only to the above-mentioned embodiments, and that it is possible to perform deformation inspections on the surface of various concrete objects other than bridge deck concrete that cannot be inspected up close by humans. It goes without saying that various other changes may be made without departing from the gist of the present invention.

[Effects of the Invention] As described above, according to the method for inspecting deformation of concrete slabs, etc. of the present invention, the concrete surface to be inspected is imaged by a measuring camera from a position far away, and the captured information is used to Since deformations on the concrete surface are detected using an analytical plotting machine, deformation inspections can be carried out efficiently, safely, and with high precision without the need for setting up scaffolding. It can have a great effect.

[Brief explanation of drawings]

Figure 1 is a side view showing an example of how a concrete floor slab surface is photographed by a measuring camera, Figure 2 is a diagram showing the relationship between photographing distance and focal length, and Figure 3 is a diagram of the Hara Cell Blood Lens Group for measuring. A diagram showing the relationship between focal length and photographing distance, Figure 4 (D (n) is an explanatory diagram showing an example of a photographing method, Figure 5 is an example of a deformation distribution map created by an analytical plotter, 6
The figures are explanatory diagrams showing examples of various photographing methods using a measuring camera, and FIG. 7 is an explanatory diagram showing an example of yet another photographing method. 1 is a pier, 2 is a concrete floor slab, 4 is a measurement camera,
5 is a lighting device, 6 is a longitudinal beam, 7 is a horizontal beam, 8 is a reinforcing beam, 9
10 is a bridge abutment, 10 is a temporary support, 11 is a floating body, 12 is an anti-vibration camera mount, and 13 is a balloon.

Claims (1)

[Claims] 1) Determine the scale and control point according to the shooting distance to the concrete surface to be inspected, photograph the concrete surface with a measurement camera, make a positive film from the photographed and developed negative, and measure the control point from the surface to be inspected. A method for inspecting deformation of floor slab concrete, etc., characterized in that the set positive film is fed into an analytical plotting machine to create a deformation distribution map of the concrete surface.