JPH1026931A - Measuring method of sagging amount of floor board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly measure a sagging amount of a floor board on an upper surface thereof by applying vibration on the upper surface thereof. SOLUTION: In a method for measuring the sagging amount of the floor board 5 of a bridge in which the floor board 5 is supported by girders 1a, when vibration us applied o a center between the girders la or to a vicinity thereof, vibration C at the center or at the vicinity thereof on the floor board 5 and vibration L or R on the girder 1a or at the vicinity thereof is measured and the vibration L or R on the girder 1a or at the vicinity thereof is subtracted from the vibration C at the center or at the vicinity thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the amount of deflection of a floor slab of a bridge such as a bridge, viaduct, highway or the like (having a bridge structure). The amount of deflection of the slab increases due to damage such as cracks in the slab. Therefore, as one method of investigating the degree of damage and the reinforcing effect of the floor slab, it is necessary to accurately measure the amount of deflection of the floor slab by top surface deflection measurement.

[0002]

2. Description of the Related Art FIG. 7 is an explanatory view of a conventional example (part 1) and FIG.
Is an explanatory diagram (part 2) of a conventional example. Hereinafter, FIGS. 7 and 8
The conventional example will be described based on FIG. (1): Description of the Bridge FIG. 7A is a description of the bridge. The main girder 1 of the bridge is supported by the abutment 2 and the pier 3 via the bearing 4.

FIG. 7 (b) is an explanatory view of a break of a bridge. FIG.
In (b), four main girders 1 are supported by piers 3 via bearings 4. A slab 5 of reinforced concrete is provided on the upper part of the girder such as the main girder 1 or the vertical girder, and an asphalt pavement 6 is provided on the upper part of the slab 5. Reference numeral 9 denotes a weighted vehicle.

[0004] (2): Description of the measurement of the amount of deflection of the floor slab FIG. FIG.
FIG. 2A is a view of a deck 5 of a bridge viewed from below, where a deck 5 is provided between a plurality of main girders 1. Weight is applied from the upper center of the floor slab 5 indicated by the black circles in the figure, and the black circles and white circles ○ on the lower surface of the floor slab 5
The deflection amount was measured by the displacement meter at the position of. The method of applying the weight is to stop (or run) the weighted vehicle 9 such as a truck having a known weight so that the center of the rear wheel is located at the center of the target floor slab 5. Also, four displacement meters are installed in the main muscle line direction (up and down direction) and the distribution line direction (left and right direction).

FIG. 8B is a view for explaining the installation of a displacement meter.
FIG. 8B shows a cross section in the main bar direction of FIG. 8A. The beam of the main girder 1 (or the vertical girder) on which the floor slab 5 rides is set as a fixed (immobile) point, and the displacement meter no. 1 to no. 3 are arranged, and this displacement meter n
o. 1 to no. In No. 3, the amount of deflection of the floor slab 5 was measured between the jig (angle) 10 for setting a displacement gauge, which is a fixed (immobile) point, and the floor slab 5.

The amount of deflection of the floor slab 5 has been used to evaluate the degree of damage to the floor slab 5 and the effect of reinforcing the floor slab 5.

[0007]

The above-mentioned prior art has the following problems. (1) It is necessary to provide a displacement gauge and a displacement gauge installation jig 10 for installing the displacement gauge on the lower surface of all the floor slabs 5 for measuring the amount of deflection.

(2) A weighted vehicle 9 such as a test truck for applying weight is required. (3) A great deal of work is required to install the displacement gauge on the bottom of the floor slab 5,
Since it takes time and cost, it is impossible to measure all of the floor slabs 5, so that only the sampling inspection (measurement) of the slab 5 which is easily damaged can be performed.

An object of the present invention is to solve such a conventional problem and vibrate on the upper surface of the floor slab 5 to reliably and easily measure the amount of deflection on the upper surface of the floor slab 5.

[0010]

FIG. 1 is a diagram illustrating the principle of the present invention. In FIG. 1, 1a is a girder, 5 is a floor slab, and C, L, and R are vibrometers (vibration). The present invention is configured as follows in order to solve the conventional problem.

(1): In the method for measuring the amount of deflection of a deck slab of a bridge in which the slab 5 is supported by the slab 1a, when the center between or adjacent to the slabs 1a is vibrated, The vibration C at or near the center and the vibration L or R on or near the girder 1a are measured, and the vibration L or R on or near the girder 1a is subtracted from the vibration C at or near the center.

(2): In the method for measuring the amount of deflection of the floor slab of a bridge in which the floor slab 5 is supported by the girder 1a, when the center between the girder 1a or its vicinity is vibrated, The vibration C at or near the center and the vibrations L and R on or near the two girders 1a are measured, and the vibrations L at or near the girder 1a from the vibration C at or near the center are measured. , R is subtracted.

(3): In the method for measuring the amount of deflection of the floor slab of a bridge in which the floor slab 5 is supported by the girder 1a, when the center between the girder 1a or its vicinity is vibrated, The vibration C at or near the center and the vibrations L and R on or near the two girders 1a are measured, and the vibrations L at or near the girder 1a from the vibration C at or near the center are measured. , R and half the torsional vibration component of the difference between the vibrations L and R at two places on or near the digit 1a.

(4): In the method for measuring the amount of deflection of the deck slab of a bridge in which the slab 5 is supported by the slab 1a, a bar supported between the columns on the slab 1a or in the vicinity of the slab 1a. , A displacement meter attached to the bar,
When the center or its vicinity is vibrated, the displacement meter measures the vibration displacement at or near the center.

(5): In the method for measuring the amount of deflection of a floor slab according to any one of the above (1) to (4), one location on the floor slab 5 between the center or its vicinity and the spar 1a or its vicinity. Or measure the vibration at multiple locations.

(6): In the method for measuring the amount of deflection of the floor slab according to any one of the above (1) to (5), a loading plate having a hole in the center for exciting the floor slab 5 is provided; The vibration of the floor slab 5 is measured by a vibrometer C provided in the hole.

(Operation) The operation based on the above configuration will be described. When the center between the girders 1a or its vicinity is vibrated, the floor slab 5
Above, the vibration C at or near the center and the vibration L or R on or near the beam 1a are measured, and the vibration L or R on or near the beam 1a is measured from the vibration C at or near the center. Subtract. For this reason, it is possible to vibrate from above the floor slab 5 and measure the amount of deflection of the floor slab 5 excluding the bending vibration component of the entire bridge on the floor slab 5.

When the center or the vicinity thereof between the girders 1a is vibrated, the vibration C at the center or the vicinity thereof and the vibrations L and R at two places on or near the girder 1a are converted on the floor slab 5. Measurement is performed, and a half of the sum of the vibrations L and R at two places on or near the beam 1a is subtracted from the vibration C at or near the center. For this reason, a vibration is applied from above the floor slab 5, and the amount of deflection of the floor slab 5 excluding the bending vibration component of the entire bridge on the floor slab 5 can be accurately measured.

Further, when the center or the vicinity between the girders 1a is vibrated, the vibration C on the floor slab 5 at or near the center is vibrated.
And two vibrations L and R on or near the girder 1a are measured, and a half of the sum of the vibrations L and R on the girder 1a or near the girder 1a from the vibration C at or near the center is measured. 1 and the difference between the two vibrations L and R on or near the beam 1a.
Subtract the torsional vibration component of the entire bridge. For this reason, it is possible to vibrate from above the floor slab 5, and to measure more accurately the deflection amount of the floor slab 5 on the floor slab 5 excluding the bending vibration component and the torsional vibration component of the entire bridge.

When the center between the beams 1a or its vicinity is vibrated, the displacement at the center or its vicinity is measured by a displacement meter. For this reason, the floor slab 5 is vibrated from above,
The amount of deflection can be measured directly without performing waveform synthesis on.

Further, vibration is measured at one or a plurality of points on the floor slab 5 between the center or its vicinity and the spar 1a or its vicinity. For this reason, a vibration is applied from above the floor slab 5, and the maximum amount of deflection at the center of the floor plate can be measured on the floor slab 5, and also the deflection alignment can be measured.

Further, a hole is provided at the center of the loading board for exciting the floor slab 5, and the vibration of the floor slab 5 is measured by a vibrometer C in the hole of the loading board. For this reason, the center vibration of the floor slab 5 can be measured, and the deflection amount of the floor slab can be accurately measured.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In the figure, the same components as those in FIGS. 1, 7, and 8 are denoted by the same reference numerals. (1): Description of synthetic waveform method In the description of the arrangement of the vibrometer in FIG. 2A, the vibrometer L is provided on the upper surface (paved surface) of the floor slab 5 of the left main girder 1, and the main girder 1 on the right.
A vibration meter R is provided on the upper surface of the floor slab 5, and a vibration meter C is provided on the upper surface of the floor slab 5 between the vibration meters L and R. As these vibrometers C, L, and R, speed sensors used in seismometers and the like can be used.

When the floor slab 5 is vibrated, an impact is applied at the position of the vibrometer C at the center between the main girders 1. The vibrating means drops a weight of several tens of kilograms so that the vibrating force becomes 5 to 10 tons.

In FIG. 2A, a displacement meter no. Is placed between the floor slab 5 and a displacement gauge installation jig 10 on the lower surface of the floor slab 5 to confirm the measurement of the amount of deflection by the upper surface. 1 is provided to directly measure the amount of deflection of the lower surface of the floor slab 5.

Generally, the main vibration modes of a bridge related to vertical vibration are bending vibration (in-plane vibration) and torsional vibration. In the description of the bending primary vibration mode in FIG. 2B, the phases of the vertical vibrations of the vibrometer L and the vibrometer R at the left and right measurement points are the same.

In the description of the torsional primary vibration mode in FIG. 2C, the phases of the vertical vibration of the vibrometer L and the vibrometer R at the left and right measurement points are opposite to each other. Therefore, when bending vibration is obtained from a random vibration waveform generated by an earthquake or traffic vibration, the sum of the vertical vibrations of the vibrometer L and the vibrometer R is 分 の as follows.

Bending vibration = (L + R) / 2 When torsional vibration is obtained, the vibration meter L
Of the vertical vibration of the vibration meter R.

Torsional vibration = (LR) / 2 or (RL) / 2 When the floor slab 5 is vibrated in the present bridge as shown in FIG. 2A, the vibration of the entire bridge and the floor slab 5 A phenomenon occurs in which the bending vibrations are combined. Thus, the composite waveform is decomposed into components to obtain a flexural vibration waveform of the floor slab 5. Specifically, as shown in FIG. 2A, the floor slab 5 center vibrometer C (actually, the center of the loading board for excitation), the vibrometer L on the main girder 1, and the vibrometer R
Vibrometers are installed at three locations to measure the vibration during excitation (bending vibration of floor slab 5 + vibration of the entire bridge). The flexural vibration waveform of the floor slab 5 is obtained by combining the three waveforms as follows.

Deflection vibration waveform = C- (L + R) / 2 When the waveforms of L and R are substantially equal, CL or C
A flexural vibration waveform can also be obtained as -R.

In the case where the torsional vibration component is also removed, it is obtained by the following equation (1) or (2). Flexural vibration waveform = C− (L + R) / 2− (LR) / 2 (1) or flexural vibration waveform = C− (L + R) / 2− (RL) / 2.・ (2) It should be noted that which of the above equations (1) and (2) is adopted
It is determined based on the torsional vibration phenomenon and the polarity of the measuring instrument.

As described above, the deflection vibration of the floor slab 5 can be accurately obtained by the three vibration sensors. As described above, in order to accurately measure the deflection by the composite waveform method, it is necessary to select a vibrometer pickup (sensor) having sufficient accuracy in the frequency response to the natural vibration of the floor slab 5 and the resolution for the minute amplitude. In addition, floor slab 5
Excitation position and measurement position for excitation from above (center of floor slab 5,
It is necessary to accurately position (on the beam).

(2): Explanation by vibration waveform FIG. 3 is an explanatory diagram by vibration waveform (No. 1), and FIG. 4 is an explanatory diagram by vibration waveform (No. 2). Hereinafter, the vibration waveform will be described with reference to FIGS.

FIG. 3 shows waveforms obtained by vibrometers C, L, and R on the upper surface of the floor slab 5 when the floor slab 5 is vibrated four times in FIG. 2A. In FIG.
C is the output waveform of the vibrometer C at the center of the floor slab 5, L is the output waveform of the left vibrometer L on the main girder 1, and R is the output waveform of the right vibrometer R on the main girder 1. is there.

(L + R) / 2 is a bending vibration waveform of the entire bridge synthesized from the output waveforms L and R. And C-
(L + R) / 2 is the flexural vibration waveform (synthetic waveform) of the floor slab 5. Numerical values in the figure 0.065, 0.06, 0.06
1, 0.061 indicates the maximum amount of deflection (mm) during vibration. In this case, since a torsional vibration component is not removed, a low vibration component which is considered to be a torsional vibration is slightly included.

FIG. 4A is an explanatory diagram of a flexural vibration waveform obtained by a displacement meter. FIG. 4A shows a displacement meter no. 4 when the floor slab 5 is vibrated four times in FIG.
1 is a deflection waveform of the lower surface at the center of the floor slab 5 obtained in FIG. Figures 0.075, 0.075, 0.074,
0.080 is the maximum deflection amount at the time of excitation (mm)
Is shown.

With this waveform, the displacement meter no. 1 with respect to the lower surface deflection of 0.075 mm (C-
(L + R) / 2) is 0.065 mm, but the vibration meter C
Considering that the installation position of the floor slab 5 is not displaced from the center of the floor slab 5 (actually, the installation position of the vibrometer sensor is displaced by about 20 cm from the center) and that the torsional vibration is not removed, a fairly accurate value is obtained. I have. In the vibration waveform of FIG. 4A, the second and subsequent waves indicated by the symbol s are affected by the vibration of the displacement meter installation jig 10.

FIG. 4 (b) is an explanation of a flexural vibration enlarged waveform of the floor slab. The waveform in FIG. 4B is a composite waveform (C
This is an enlarged waveform corresponding to one excitation of-(L + R) / 2, and faithfully reproduces a situation in which the load (excitation) weight bounces several times. In addition, there is no vibration effect after the second wave included in the lower surface deflection waveform (no. 1).

As described above, the composite waveform (C- (L +
If the torsional vibration component is also removed in addition to R) / 2), the composite waveform method can more accurately represent the flexural vibration of the floor slab 5 than the current lower surface flexure measuring method.

(3): Description of the Deflection Measuring Apparatus FIG. 5 is an explanatory diagram of the deflection measuring apparatus, FIG. 5 (a) illustrates the vibration section, and FIG. 5 (b) illustrates the deflection measuring circuit. It is.

In FIG. 5A, the floor slab 5 is placed on the main girder 1.
Is provided. The vibration meter is a vibration meter L directly above the floor slab 5.
1, R1, vibrometer C at center of floor slab 5, vibrometer L1, R1
Like the vibrometers L2 and R2 between the vibrometer C and the vibrometer C, they are provided at five places on the floor slab 5. The vibrating section is provided with a loading board 11 on the floor slab 5, a bottom board 12 serving as a receiving table, a rubber plate 13, a loading weight 14, a shaft 15, and a hook 16.

The vibrating operation of the vibrating section is performed by the upper hook 1
The loading weight 14 fixed to 6 is removed from the hook 16 and dropped along the shaft 15 to the position indicated by the dotted line. The impact force at the time of falling is applied to the floor slab 5 through the rubber plate 13, the bottom plate 12, and the loading plate 11. Note that a hole is provided in the center of the loading board 11, and the vibrometer C can be installed in this hole.

In FIG. 5B, the deflection measuring circuit is provided with a plurality of vibrometer sensors 21, 22,... N, an amplifier (amplifier) 31, a storage operation unit 32, and an output unit 33. The operation of the deflection amount measuring circuit is such that the outputs from the plurality of vibrometer sensors 21, 22... N provided on the floor slab 5 are amplified by the amplifier 31 and output to the storage operation unit 32.
The storage operation unit 32 combines the output waveforms from the amplifier 31 to determine the deflection waveform at each vibration meter installation location, and
Output to The output unit 33 outputs the output from the storage operation unit 32 to a printer, a display, or the like.

As described above, by increasing the number of vibrometers, a detailed flexural vibration waveform at each position of the floor slab 5 can be obtained, and a flexural shape can be obtained.

(4) Description of Measurement Method Using Displacement Meter FIG. 6 is an explanatory diagram of a measurement method using the displacement meter. In FIG. 6, a bar 6 is provided on the floor slab 5 and supported by a column 7 on or near the spar 1a. The position of this support 7 is
The interval can be adjusted according to the interval of the column 1a. And bar 6 has displacement meters Cn, Ln, Rn.
Is attached.

When the floor slab 5 is vibrated, an impact is applied at the position of the displacement meter Cn at the center between the girders 1a. This vibration means
The same one as described with reference to FIG. 5A can be used. In this case, the displacement meter Cn is installed in the center hole of the loading board 11. However, the vibrating means does not come into contact with the bar 6 due to a structure straddling the bar 6 or the like.
Is not excited.

The deflection amount of the floor slab 5 is measured when the floor slab 5 at the center between the girders 1a or in the vicinity thereof is vibrated.
Ln and Rn are used to measure the relative displacement (vibration displacement) between the bar 6 (which is a fixed point) and the floor slab 5.

In this manner, the vibration is applied from above the floor slab 5,
There is no need to combine waveforms on the floor slab 5, and the amount of deflection can be measured directly. As described above, since the measurement of the amount of deflection of the floor slab 5 can be performed on the floor slab 5 by vibrating the floor slab 5, the conventional measurement work on the lower surface of the floor slab 5 is eliminated. The measurement can be performed in a short time and at low cost, and the amount of deflection of all floor slabs 5 of the bridge can be measured.

[0049]

As described above, the present invention has the following effects. (1): The center of the girder or its vicinity is vibrated, and on the floor slab,
To measure the vibration at the center or its vicinity and the vibration at or near the girder, and to subtract the vibration at or near the girder from the vibration at the center or near the girder, perform special construction on the floor slab. The amount of deflection can be easily measured without performing.

(2) On the floor slab, the vibration at or near the center between the girders and the vibration at or near the two girders are measured, and the vibration at or near the center is measured from the vibration at or near the center. Since the half of the sum of the vibrations at the two nearby locations is subtracted, the amount of deflection can be easily and accurately measured without performing special construction on the floor slab.

(3): On the floor slab, the vibration at or near the center between the girders and the vibration at or near the two girders are measured, and the vibration at or near the center is measured from the vibration at or near the center. Special work on the floor slab 5 to subtract a half of the sum of the vibrations at two nearby locations and a half of the torsional vibration component of the difference between the vibrations at or near the girders. The deflection amount can be easily and more accurately measured without performing.

(4): When the center between the girders or its vicinity is vibrated, the displacement at the center or its vicinity is measured by a displacement meter attached to a bar on the floor slab. The amount of deflection can be measured directly without shaking and performing waveform synthesis on the floor slab.

(5): The vibration is measured at one or more places between the center or its vicinity and the girder or its vicinity on the floor slab. Amounts can be measured, as well as deflection linear measurements.

(6): Vibration of the floor slab is measured by a vibrometer in the hole of the loading board provided with a hole at the center for exciting the floor slab.
Vibration at the center of the floor slab can be accurately measured, and the amount of deflection of the floor slab can be accurately measured.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is an explanatory diagram of a combined waveform method according to the embodiment.

FIG. 3 is an explanatory diagram (part 1) based on a vibration waveform in the embodiment.

FIG. 4 is an explanatory view (part 2) based on a vibration waveform in the embodiment.

FIG. 5 is an explanatory diagram of a deflection amount measuring device according to the embodiment.

FIG. 6 is an explanatory diagram of a measurement method using a displacement meter according to the embodiment.

FIG. 7 is an explanatory diagram (part 1) of a conventional example.

FIG. 8 is an explanatory view (part 2) of a conventional example.

[Explanation of symbols]

 1a digit 5 Floor slab C, L, R Vibrometer (vibration)

Claims (6)

[Claims] 1. A method for measuring the amount of deflection of a slab of a bridge in which a slab is supported by a girder, the method comprising: A method for measuring the amount of deflection of a floor slab, comprising measuring vibration and vibration on or near the girder, and subtracting vibration on or near the girder from the measured vibration at or at the center. 2. A method for measuring the amount of deflection of a floor slab of a bridge in which a slab is supported by a girder, the method comprising: Measuring the vibration and the vibration at or near the two girders, and subtracting half of the sum of the two vibrations at or near the gird from the measured vibration at or near the center. A method for measuring the amount of deflection of a floor slab, characterized by the following. 3. A method for measuring the amount of deflection of a slab of a bridge in which a slab is supported by a girder, wherein when the center or the vicinity of the girder is vibrated, the center or the vicinity of the center on the slab is vibrated. Vibration and vibrations at or near the girder at two locations are measured. From the measured vibration at the center or near the girder, a half of the sum of the vibrations at or near the girder at the two locations and the girder are measured. Alternatively, a method for measuring the amount of deflection of a floor slab, wherein a torsional vibration component of a half of a difference between two vibrations in the vicinity thereof is subtracted. 4. A method for measuring the amount of deflection of a slab of a bridge in which a slab is supported by a girder, the method comprising: a bar supported between columns on or near the girder on the slab; And a vibration gauge at the center or in the vicinity thereof when the center or the vicinity thereof is vibrated, the vibration displacement being measured by the displacement meter. 5. The method according to claim 1, wherein the vibration is measured at one or a plurality of positions on the floor slab between the center or the vicinity thereof and the girder or the vicinity thereof. The method for measuring the amount of deflection of the slab described in the above. 6. A loading plate provided with a hole in the center for exciting the floor slab, and the vibration of the floor slab is measured by a vibrometer provided in the hole of the loading slab. Item 6. The method for measuring the amount of deflection of a floor slab according to any one of Items 1 to 5.