JP2002090256A - Evaluation method for soundness degree using dimensionless rigidity ratio of concrete floormboard - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that the application range of a visual observation method is limited when a floorboard is waterproofed, that a large-scale platform is required for measuring a bending stress because a rigidity method, a flexure method and a stress intensity method are methods in which a constant-load vehicle is loaded statically or dynamically on a bridge, that the reproduction reliability of a calculated value is low because a complicated hypothesis, the calculation of a board theoretical solution or the like is required and because an irregularity in a result is large, that a method in which the modulus of elasticity, the crack depth or the like of the floorboard is investigated so as to find the safety factor on margin of a punching shear is troublesome in the measurement of the crack depth and that its calculation is complicated. SOLUTION: In the evaluation method for the soundness degree of a concrete floorboard the dynamic flexure in the central part in the effective span of the floorboard is frequency- measured, and a dynamic flexure difference is found on the basis of its cumulative percentage curve. On the basis of the ratio of the dynamic flexure difference to the length of the effective span of the floorboard, the degradation degree factor of the floorboard which uses the dynamic flexure difference as a variable is found. On the basis of the degradation degree factor and on the basis of a degradation degree in the final state of the floorboard, a dimensionless rigidity ratio as the ratio of both factors is found. While the dimensionless rigidity ratio is used as a reference, the soundness degree of the floorboard is evaluated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundness evaluation method using a dimensionless rigidity ratio of a concrete slab, and relates to a maintenance technique of bridge engineering. The present invention relates to a diagnostic technique for early detection of sickness.

[0002]

2. Description of the Related Art In general, there are the following methods for evaluating the soundness of concrete structures. (1) Empirical method: A method of empirically estimating the load carrying capacity from a visual inspection of cracks in concrete and corrosion of reinforcing steel. (2) Rigidity method: Deflection and stress are determined by applying a load,
A method of analyzing the plate theory and comparing it with the calculation results of all sections effective and RC sections. (3) Deflection method: A method of comparing a deflection value and a calculated value as described above. (4) Stress degree method: A method in which the stress degree is calculated in consideration of the cross-sectional deficiency of a reinforcing bar, and if the stress level is equal to or less than the allowable stress level, it is determined that there is a load bearing capacity. (5) Others: A method for determining the load carrying ratio of the punching shear fracture, such as the fracture safety factor method for floor slabs. The right side of FIG. 4 shows the concept of the conventional calculation methods (2) and (3).

[0003]

The method (1) is intended for wide, shallow, and efficient inspection by visual inspection.
This is an empirical method for objectively determining visual inspection from past damage cases, such as the crack density method and the free lime method. However, in recent years, floor slab waterproofing work has become common in construction and maintenance, and its application range has been limited. (2), (3) and (4)
The method is a method of statically or dynamically loading a constant load vehicle on a bridge, and is a method of measuring deflection and bending stress of a floor slab and a girder. In this case, a large-scale work platform is required. In this analysis of the measurement results, the calculated values of plate theory and the like are compared with the actually measured values.However, it is necessary to set the load distribution coefficient and the member rigidity of the girder of each member, anti-tilt structure, floor slab and ground cover / wall height column. is there. In particular, when there is a reinforcing member such as an intermediate vertical girder or a thickened floor slab, it is necessary to set a composite effect of the concrete and the girder. In this way, the measurement method becomes large-scale due to lane regulation, and the calculated values require complicated assumptions and calculations such as plate theoretical solutions, and the results vary widely. Evaluation is low. Method (5) is
In this method, the Young's modulus and crack depth of the floor slab are investigated to determine the fracture safety factor of punching shear. Measuring crack depth is cumbersome and cumbersome to calculate. The present invention
Focusing on the need for a survey method that can quantitatively obtain the information necessary for repair and reinforcement by simple measurement as described above, the soundness evaluation method based on the dimensionless rigidity ratio is supported by a large number of measurement data. It was realized as a bridge diagnostic technology. Accordingly, an object of the present invention is to provide a simple and reproducible evaluation method focusing on the slab rigidity in the field of bridge slab maintenance.

[0004]

A soundness evaluation method using a non-dimensional stiffness ratio of a concrete slab according to the present invention measures a frequency of a dynamic deflection of a central portion of a slab of a slab and calculates a dynamic deflection from a cumulative percentage curve. Find the deflection difference. From the ratio between the dynamic deflection difference and the floor slab span length, a deterioration degree coefficient of the current floor slab using the dynamic deflection difference as a variable is obtained. From the deterioration degree coefficient and the deterioration degree coefficient in the final state of the reference slab, a dimensionless rigidity ratio, which is a ratio of the two coefficients, is obtained. Then, the soundness of the floor slab is evaluated based on the dimensionless rigidity ratio.

In order for the present invention to be established, the following prerequisites are required. (1) Reinforced concrete slabs are designed and constructed based on design standards, and slabs constructed at the same time are within a substantially constant rigid cross section. (2) Since the traveling vehicle is traveling between the lane marks, the loading position and the load are statistically substantially the same aggregate except for some overloaded vehicles. ) The rigidity ratio of the floor slab and the members supporting the floor slab can be calculated from the dynamic deflection frequency measurement described above. (3) Since any slab supports a predetermined wheel load, if the rigidity ratio of the slab and the members supporting the slab is managed within a certain range, the "safety and usability" of the predetermined bridge Is obtained.

[0006] The failure mode of the floor slab is punching shear failure. The condition is that the floor slab, which is a bending member, has a reduced bending stiffness and reaches punching shear failure. In addition, when the bending stiffness of the slab is healthy (above a certain level) in the steel bridge, the live load is reduced by reducing the stress generated in the cross sections of the girder, the inclined structure, and the horizontal structure by the load distribution of the slab. So
As long as the rigidity of the floor slab is sound, there is generally little risk of fatigue failure of the steel member.

[0007] The frequency measurement of the dynamic deflection may be performed over 24 hours. In this case, the measurement frequency increases, and the measurement accuracy increases. Of course, more than 24 hours is more preferable, but if it is 24 hours, the minimum condition is secured.

[0008] The frequency measurement may be performed by a contact sensor. In this case, the contact sensor is large in size, but when a suspended scaffold such as a painted scaffold is installed, a large number of panels can be measured simultaneously.

[0009] The frequency measurement may be performed by a non-contact sensor. In this case, measurement can be performed at a point away from the floor slab.

[0010] The non-contact sensor may be a laser Doppler vibrometer. In this case, the light beam may be directed directly to the lower surface of the floor slab, or may be irradiated from the horizontal direction via a reflecting mirror, and the degree of freedom of the installation position of the laser Doppler vibrometer is increased.

[0011] The dynamic deflection difference may be measured between 10% and 50%. In this case, the influence of factors such as non-linearity and loading conditions can be almost eliminated.

The degradation coefficient in the final state of the reference slab may be a numerical value for the reference slab obtained from frequency measurement data of a large number of damaged slab panels. The actual ultimate state of the floor slab refers to the point at which partial punching shear failure occurs. In this case, since the deterioration degree coefficient in the final state can be specified from the results of verification of many floor slabs, the deterioration degree of the floor slab can be determined by employing the deterioration degree coefficient in the final state.

[0013] The dynamic deflection may be caused by a dynamic load of a 15t and 20t constant load vehicle. in this case,
Since deflection by both loads of 15t and 20t is obtained,
Deflection closer to the actual body can be measured.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a conceptual diagram showing the relationship between floor slab damage and repair / reinforcement, and FIG.
FIG. 3 is a schematic view of a floor slab deflection measuring device using displacement sensors of a contact type and a non-contact type sensor, FIG. 3 is a right side view of FIG. 2, and FIG. 4 is an explanatory diagram of a soundness evaluation method based on a rigidity ratio of the floor slab. The left side of the dashed line indicates the degree of deterioration due to running of a general vehicle, and the right side indicates the degree of deterioration due to a constant load test. On this left side, (a) is a schematic diagram of the same measuring device as in FIG. 2, (b) is a diagram showing the state of deflection δ, (c) is a deflection-frequency curve diagram, and (d) is the deflection frequency of the cumulative percentage. FIG. 7E is a diagram illustrating a curve C ′, and FIG. 7E is a diagram illustrating a relationship between a dimensionless rigidity ratio (load to deflection ratio). On the right side, (a ') is a diagram corresponding to (a), (b') is a diagram corresponding to (b), (e ') is a diagram corresponding to (e), and (f') is a diagram corresponding to (e). It is a figure which shows the relationship between the crack of a floor slab, and a neutral axis | shaft. 5A and 5B are comparison diagrams of the concept of the dimensionless rigidity ratio method and the deflection method. FIG. 5A shows the degree of deterioration of a general traveling vehicle and FIG.

In FIG. 1, the horizontal axis represents time t, and the vertical axis represents load carrying capacity P. Regarding the rigidity of the floor slab 1, 18
cm, the improved version is 9 cm thicker. A floor plate injury model curve, B is the curve after increasing Atsuko P ₁ of 5 cm, C curve after 9cm ZoAtsuko P ₂ is, D and E shows the state of peeling the old and new concrete. Further, t ₁ is the start of use, t ₂ is the time repair reinforcement. d ₁ is the allowable value, d ₂ is used limit, d ₃ is in service limit, d ₄
Is the final state. L ₁ is survival by + 5cm increase of Atsuko,
L ₂ shows the survival by + 9cm increase of Atsuko.

The evaluation procedure is as follows. (1) As shown in FIGS. 2, 3, 4, 5, and 17,
Frequency of dynamic deflection δ at the center of span S of floor slab 1 is constant
Frequency measurement by Peak-Valley method etc.
And the number of relative deflections required for statistics (24 hours or more per unit time)
Or 2,000 heavy vehicles)
Recorded in a ladder, statistically processed, and the relative deflection difference of the floor slab
(Δ_Ten−δ₅₀) From the deflection frequency curve C of the cumulative percentage.
Confuse. The dynamic deflection is calculated from the ratio between the dynamic deflection difference and the floor slab length L.
Degradation coefficient A of floor slab with difference as variable_sAsk for. This poor
Conversion coefficient A_sAnd deterioration factor A in the final state of floor slab 1
_{science fiction}Dimensionless stiffness ratio A, which is the ratio of the two coefficients_s/ A_{science fiction}Ask for
You. And this dimensionless rigidity ratio A_s/ A_{science fiction}Based on
Evaluate the soundness of the concrete slab.

(2) Degradation degree ΔA ( _s /
_The formula for _{calculating sf} )｝ is as follows. Referring to FIG.
On the left,

(Equation 1) However, δ ₁₀ -δ _50: when a general car running the measured deflection _{(mm) δ '10 -δ'} 50: evaluation value of ultimate state (mm) P ₁₀ -P _50: overweight difference at the time of other vehicles traveling ( t)

In the case of the deflection method on the right side,

(Equation 2) Where δ ₁ : Theoretical deflection of the entire cross section (mm) δ ₂ : Theoretical deflection of the RC cross section (mm) δ: Measured deflection of constant load vehicle (mm)

The final state of the floor slab 1 is as follows. Ultimate state ^{_{A sf = 35 × 10 -12 (}} mm -2) degradation coefficient of deck _{A s A s = (δ 10} -δ 50) / L 3 ............... (3) = (P 10 -P ₅₀ ) / EI ... (3) 'where E: elastic modulus of member I: second moment of area

In the above, to relate equations (1) and (2)

(Equation 3)

The specific ratio of the deterioration coefficient of the floor slab is as follows. Here _{A (s / sf) = 1.7} × 10 17 (δ 10 -δ 50) / (d · L) 3 = 0~1 ............... (1) ', A s: the deck deterioration Degree coefficient A _s = (δ ₁₀ −δ ₅₀ ) / L ³ (mm ⁻² ) A _sf : Degradation coefficient A _sf = 35 × 10 ⁻¹² (mm ⁻² ) in the final state of the standard slab (d) = 18 cm. ) The deterioration degree coefficient in the design use limit state is set to _Asf / 2. For simplicity, the load-deflection curve has a linear relationship. δ ₁₀ , δ ₅₀ : Cumulative percentage of deflection frequency curve 10%, 50% deflection value (mm) L: Slab length (mm) d: Thickness of current floor slab (mm)

[0022]

[Table 1] [Table 1] shows a calculation example and an application formula. (Note) The correction coefficients for the reference slabs in the symbol column of this table are underlined in the applicable formula and in the description of the unit (1).
Also, the bold characters in the unit column of the table are the bold characters included in the expression of the dimension (2) of “Description of Unit”.

The deterioration degree A (_s/_{science fiction}) = A_s/ A_{science fiction}
Is theoretically influenced by various factors such as nonlinearity and loading conditions.
Is affected, but the deflection difference of the floor slab (δ_Ten−δ₅₀) And rigidity ratio
(A _s/ A_{science fiction}), Most of the factors are eliminated.
And the load-carrying capacity evaluation of practical floor slabs falls within ± 10%
Equation (1) 'is obtained.

Therefore, if the bending stiffness ratio of the floor slab decreases (0 → 1) as shown in the floor slab damage model curve in FIG. to manage, control value by a constant flexural rigidity ratio as in Table 2 define the {deterioration degree _{a (s / s f)}} , it is assumed that maintenance management at less.

[0025]

[Table 2] [Table 2] shows "Judgment value by soundness evaluation method of steel bridge deck".

FIG. 6 is a graph showing the relationship between the degree of deterioration of all the measured data and the dynamic deflection. It can be seen that there is a relationship between the dynamic deflection δ ₁₀ and the degree of deterioration of the 18 cm thick reference slab. R ² is a correlation coefficient. In addition, the deterioration determination coefficient in the use limit state (A ( _s / _sf ) = 0.5) of the standard slab (d) = 18 cm of the control judgment value and the measurement method in Table 2 (A ( _s / _sf ) = 0.5) and the final state were obtained by the past fatigue tests and This is set based on a large number of deflection frequency measurement data.
In the future, by accumulating more frequency measurement data, the reliability will be further improved.

[0027]

[Table 3] [Table 3] shows a simple calculation example of a deflection frequency distribution by a large vehicle motion waveform on an arbitrary panel, where (a) shows a case using a contact-type sensor and (b) shows a case using a reflection-type non-contact-type sensor. .

FIG. 7 is a frequency-deflection diagram obtained by plotting (a) and (b) in Table 3 together, and shows the correlation between the contact type and the non-contact type.

[0029]

[Table 4] [Table 4] is an example of measurement by contact and non-contact sensors at the Shinozaki viaduct on Keiyo Road.

FIG. 8 is a graph of Table 4 in terms of the relationship between the frequency% and the deflection, and it can be seen that there is a correlation.

The reinforced concrete slab is a member that directly supports the wheel load, and is always under heavy traffic and is subjected to repeated and repeated loads by an overloaded vehicle. In addition, they are used in various environments, and are exposed to natural environmental conditions such as severe high temperature and high humidity and freezing and thawing. Therefore, a different position from the general structure maintenance management method is required. In particular, in bridge maintenance, steel bridge decks serve as key members for detecting initial damage to bridges. For this reason, in evaluating the “usability and safety” of the entire bridge system, the evaluation method based on the rigidity ratio of the floor slab is an extremely effective parameter.

Referring also to FIG. 1, the thickness d of the existing floor slab 1 is conceptually 18 to 20 cm. If the bending rigidity of the floor plate 1 is healthy (between 0 to P _1), is less fatigue damage including other steel members. However, under heavy traffic, if the tire is repeatedly fatigued for about 20 years or more, the rigidity of the floor slab gradually starts to decrease, and a local crack damage appears in the joint 5 between the main girder 3 and the inclined structure 4.

In the design use limit state P _{1 in} FIG. 1, the time when the crack 6 reaches the neutral axis 7 is an RC cross section (ignoring tension,
n = 15), but if the floor slab 1 is used for a long period of time, a large number of turtle-shaped cracks are generated and free lime elutes from the penetrating cracks.

Even in this state, since the reinforcing bar stress is below the allowable value, a considerable load can be repeatedly applied until the final state, ie, the punching shear failure. For this reason, even if the usage limit is exceeded, from the road management, if partial replacement is performed,
The floor slab is temporarily usable.

If the floor slab is not reinforced and left outside the service limit (t3 to D) as shown in FIG.
Road administrative serviced limit (closures, etc.) d ₂ be exceeded, the safety on the road feature can not be maintained. Even if repairs and reinforcements such as thickening work are performed at this stage, the effect and sustainability cannot be expected, and serious damage is caused in terms of road function.
It is a situation such as a complete replacement.

However, before the use limit state (d ₂ ), as shown in “+5 cm thickening work” or “+9 cm thickening work” in FIG. In this case, functional maintenance (usability and safety) can be ensured at a relatively low cost and efficiently over a long period of time.

That is, in the conceptual view of the floor slab life shown in FIG. 1, repair / reinforcement must be completed before reaching the use limit state where reinforcement can be performed only by lane regulation without leaving the initial slab damage. . For this purpose, it is urgently necessary to collect reliable slab damage information necessary for repair planning, such as the necessity and priority of repair, the extent of repair, and the construction period. The visual inspection based on the conventional empirical method alone cannot provide information on the initial damage of deformation due to a minute decrease in rigidity of the floor slab or a change in the deformation of the floor slab cross-section due to corrosion of reinforcing steel. With this evaluation method, the floor slab can be easily and quickly evaluated.

The average wheel load Pt / wheel running on the actual floor slab is approximately the average load P = 6t / the dimensionless stiffness ratio of a general vehicle showing around one wheel and the load of the 15t and 20t vehicles with a constant load vehicle. Based on the deflection load and the dimensionless rigidity ratio, as shown in Table 5 and FIG. 9, the measurement system of the average wheel load Pt / wheel was completed. As shown in FIG. 6, the soundness evaluation value ( Degree of deterioration) can be compared to some extent on any expressway line, between lines or between bridges.

FIG. 9 is a plot of the relationship between the degree of deterioration caused by the ordinary traveling vehicle and the load vehicle shown in the actual measurement example in Table 5, and the degree of deterioration obtained from the previous traveling of the ordinary vehicle and the above-described constant load vehicle traveling. There is a strong correlation with the degree of deterioration.

[0040]

[Table 5] [Table 5] shows the respective deterioration degree coefficients based on the actual measurement results of the contact type sensors of the 20t car and the 15t car at the Ubukubo viaduct. Here, the entrainment load difference of No. 2 is converted into a load difference when the average value P of No. 8 is set to P = 6t. Determine the degree of deterioration based on the dimensionless rigidity ratio of No. 12. The results are plotted in FIG.

[0041]

[Table 6] [Table 6] shows the measurement results of the dynamic loading test.

In particular, this method is excellent in reproducibility of measured values. When monitoring before and after reinforcement in the same panel, this is a measurement system that enables high-precision relative comparison as shown in FIG.

Further, this system makes it possible to make a relative comparison to some extent without being influenced by the line or bridge, the traffic characteristics as shown in FIG. 11, and the measurement time as shown in FIG.

If the measurement is performed for a unit time of 24 hours or more,
The dimensionless rigidity ratio of the floor slab is required. FIG. 13 is a diagram showing the relationship between the measurement time of 48 hours and the deterioration degree of 24 hours.

[0045]

[Table 7] [Table 7] and FIG. 14 are deflection data of an arbitrary large vehicle when used in [Simple calculation example] of [Table 3]. This comparison table compares the waveform data of the contact type sensor and the waveform data of the non-contact type sensor by the absolute value of the deflection as shown in FIG. 5 for non-contact sensors compared to contact sensors
%, But closely approximated.

FIG. 14 is a graph showing a comparison between the contact type sensor and the non-contact type sensor based on the numerical values in [Table 7].
There is a strong correlation between the two.

FIG. 15 is a comparison of the deflection waveform data of a large vehicle, showing the correlation between them.

As a result of partially improving the laser Doppler vibrometer so as to enable long-term on-site measurement and measurement of a low-period vibration region, stable measurement has become possible.

[0049]

[Table 8] [Table 8] shows contact type (D-1) and non-contact type (R-2:
(Reflection type) sensor. As is clear from this table, as a result of a comparison between the contact type of the conventional electric displacement meter and the non-contact type by the Lass Doppler vibrometer, which was conducted for the first time in full scale, the non-contact type was better than the contact type. It was found to show a slightly smaller value.

FIG. 16 is a graph comparing the degree of deterioration of the contact type (D-1) and that of the non-contact type (R-2: reflection type) sensor. The correlation between the two is clearly apparent.

Moreover, if a laser Doppler vibrometer is used, the measurement can be performed without being restricted by the use condition of the lower surface of the floor slab, depending on the measuring method.

FIG. 17 shows three methods of measuring the relative deflection δ of the floor slab 1 using the laser Doppler vibrometer 23. (A) when the relative deflection δ of the floor slab 1 is measured from the ground E by the [R1 method], and (b) when the relative deflection δ is measured from above a pier or the like via the mirror reflector M by the [R2 method]. c) is a case where the measurement is performed from the simple beam B by the [R3 method].

The measurement of the frequency of movement deflection is performed over 24 hours. In this case, if a certain large-sized vehicle is running, the measurement frequency increases, and the dimensionless rigidity ratio of the floor slab is obtained, so that stable data can be obtained by measurement.

The frequency measurement is performed by the contact sensor 21. In this case, the contact sensor 21 is large in size, but when there is a suspended scaffold such as a painted scaffold, the contact sensor 21 can perform a larger number of simultaneous measurements.

The frequency is measured by the non-contact sensor 22. In this case, the measurement can be performed at a point away from the floor slab.

The non-contact sensor 22 is a laser Doppler vibrometer 23. In this case, if the laser Doppler vibrometer 23 can be installed below the floor slab 1, install it here and direct the light beam directly to the lower surface of the floor slab 1. If there is a river or a railway line and cannot be installed directly below, the pier And irradiate it from the horizontal direction, and slab 1
May be applied to the lower surface of the laser Doppler, and the degree of freedom of the installation position of the laser Doppler vibrometer 23 is increased.

The dynamic deflection difference is measured between 10% and 50%. In this way, the effects of factors such as non-linearity and loading conditions can be almost eliminated.

The deterioration degree coefficient A _{sf in} the final state of the slab 1 is a numerical value for the reference slab obtained from frequency measurement data of a large number of damaged slab panels. In this case, the actual final state of the floor slab refers to the point of time when partial shearing failure occurs, but the deterioration degree coefficient A _sf of the final state can be identified from the results of verification of many floor slabs. Therefore, by adopting the deterioration degree coefficient A _sf in the final state, the deterioration degree of the floor slab can be determined.

The dynamic deflection is caused by the dynamic loading of the 15t and 20t constant load vehicles. Then, 15t
And a deflection due to both loads of 20t can be obtained, so that a deflection closer to the actual body can be measured.

[0060]

According to the present invention, there are the following features. (1) The damage level of the floor slab can be evaluated simply and simply by performing a dynamic deflection measurement from the lower surface of the floor slab using a general traveling vehicle at the center of the span without requiring complicated calculations. (2) Early damage can be detected and dealt with at an early stage, maintenance can be performed by "management value based on rigidity ratio of floor slab", and execution plan and budget management with reduced cost can be efficiently performed. (3) The concrete slab of the steel bridge plays the role of a key member for detecting initial damage to the bridge. By managing the slab, at least the "usability" and "safety" of the bridge Nature "can be secured. (4) In the cost-effectiveness analysis, at least the cost reduction effect is 1 /
At about 8, the effect of stiffness recovery (P2 to C) is more than three times with repair (+ 5cm) simply with functional recovery and improved reinforcement (+ 9cm) considering 25t, and early detection of early damage So, if you do "early response" by increasing thickness,
Cost reduction of about 1/10 or more can be realized.

According to the second aspect, the frequency of dynamic deflection is measured over 24 hours. Therefore, if a large vehicle is running to some extent, the frequency of measurement increases, and the dimensionless rigidity ratio of the floor slab is obtained. Stable data can be obtained by measurement.

According to the third aspect, since the frequency measurement is performed by the contact sensor, the contact sensor becomes large in size, but when there is a hanging scaffold such as a paint scaffold, the contact sensor can measure a larger number of simultaneous measurements. it can.

According to the fourth aspect, since the frequency measurement is performed by the non-contact sensor, the measurement can be performed at a point away from the floor slab.

According to the fifth aspect, since the non-contact sensor is a laser Doppler vibrometer, if the laser Doppler vibrometer can be installed below the floor slab, it is installed here and directly on the lower surface of the floor slab. If the beam cannot be installed directly under a river or railroad track, it can be installed on a pier and illuminated from the horizontal direction, and applied to the underside of the floor slab via a reflector. The degree of freedom of the installation position is expanded.

According to the sixth aspect, since the dynamic deflection difference is measured between 10% and 50%, the influence of factors such as nonlinearity and loading conditions can be almost eliminated.

According to the seventh aspect, since the deterioration degree coefficient in the final state of the floor slab is a value of the reference floor slab obtained from the frequency measurement data of a large number of damaged slab panels, the actual floor slab has a value. The final state of the slab refers to the point of time when partial shearing failure occurs, but the deterioration coefficient of the final state can be specified from the results of verification of many floor slabs. By using the coefficient, the degree of deterioration of the floor slab can be determined.

According to claim 8, the dynamic deflection is 15t and 2t.
Since the deflection is caused by the dynamic load of the constant load vehicle of 0t, the deflection by both the loads of 15t and 20t is obtained, and the deflection closer to the actual body can be measured.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing the relationship between damage to a floor slab and repair / reinforcement.

FIG. 2 is a schematic diagram of a load distribution by a general traveling vehicle and a deflection measurement device of a floor slab using displacement sensors of contact type sensors and non-contact type sensors.

FIG. 3 is a right side view of FIG. 2;

4A and 4B are explanatory diagrams of a soundness evaluation method based on a dimensionless rigidity ratio of a concrete floor slab, wherein FIG. 4A is a schematic diagram of a measuring device similar to FIG. 2, FIG. 4B is a diagram showing a state of deflection δ, c) is a deflection-frequency curve diagram, (d) is a diagram showing a deflection frequency curve C of the cumulative percentage, (e) is a diagram showing the relationship between the dimensionless rigidity ratio (load to deflection ratio) and the degree of deterioration, (a ') ) Is (a)
(B ') is a diagram corresponding to (b), (e') is a diagram corresponding to (e), and (f ') is a diagram showing the relationship between cracks and the neutral axis of the floor slab. is there.

FIGS. 5A and 5B are comparison diagrams of the concept of the dimensionless rigidity ratio method and the deflection method, wherein FIG. 5A shows the degree of deterioration of a general traveling vehicle and FIG.

FIG. 6 is a diagram showing the relationship between the degree of deterioration of all measurement data and the deflection.

FIG. 7 is a graph showing the percentages of deflection (a) and (b) in Table 3 together.

FIG. 8 is a cumulative percentage-deflection diagram in which (a) and (b) in [Table 3] are graphed together. From this figure, δ ₁₀ , δ
[Table 4] is the value obtained by reading ₅₀ and substituting it into the above equation (1) ′.

FIG. 9 is a diagram showing the relationship between the degree of deterioration caused by a general traveling vehicle and a load vehicle.

FIG. 10 is an explanatory diagram of a measurement system capable of high-accuracy relative comparison.

FIG. 11 is a diagram showing a difference between traffic characteristics on weekdays and holidays.

FIG. 12 is a diagram showing the relationship between the degree of deterioration, the measurement time, and the number of large vehicles, and shows the basis for making a relative comparison without being affected by a measurement period or the like.

FIG. 13 is a diagram showing a relationship between a measurement time of 48 hours and a deterioration degree of 24 hours.

FIG. 14 is a comparison diagram of a contact type sensor and a non-contact type sensor.

FIG. 15 is a comparison diagram of dynamic deflection data of a large vehicle.

FIG. 16 is a comparison diagram of the degree of deterioration between a contact type sensor and a non-contact type sensor.

17A and 17B are diagrams showing a measurement method using a laser Doppler vibrometer, wherein FIG. 17A shows the R1 method, FIG. 17B shows the R2 method, and FIG. 17C shows the R3 method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Floor slab S span delta deflection 2 Frequency meter 21 Contact sensor 22 Non-contact sensor 23 Laser Doppler vibrometer M Mirror reflector B Simple beam

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kimiaki Akai 5-7-18 Higashi-Nippori, Arakawa-ku, Tokyo F-term (reference) 2G061 AB05 BA15 CA08 EA02 EA04

Claims (8)

[Claims] 1. The dynamic deflection of the center of the span (S) of the floor slab (1)
(δ) is measured to determine the dynamic deflection difference (δ ₁₀ −δ ₅₀ ) from the cumulative percentage curve (C ′), and this dynamic deflection difference and the floor span length
Deterioration coefficient of floor slab using dynamic deflection difference as a variable from the ratio of (L)
(A _S ) is obtained, and a dimensionless rigidity ratio (A _S / A _Sf ), which is a ratio of the two factors, is obtained from the deterioration degree coefficient and the deterioration degree coefficient (A _Sf ) in the final state of the reference slab. A soundness evaluation method using a dimensionless stiffness ratio of a concrete slab characterized by evaluating the stiffness ratio as a reference. 2. The method according to claim 1, wherein the frequency of the dynamic deflection (δ) is measured for 24 hours. 3. The method according to claim 1, wherein said frequency measurement is performed by a contact sensor. 4. The method according to claim 1, wherein the frequency measurement is performed by a non-contact sensor (22). 5. The method according to claim 4, wherein the non-contact sensor is a laser Doppler vibrometer. 6. The dynamic deflection difference (δ ₁₀ −δ ₅₀ ) is 10% and 5%.
The soundness evaluation method using a dimensionless rigidity ratio of the concrete slab according to claim 1, which is measured between 0%. 7. The deterioration degree coefficient (A _Sf ) in the final state of the reference slab is a numerical value for the reference slab obtained from frequency measurement data of a large number of damaged slab panels.
A soundness evaluation method using the dimensionless rigidity ratio of the concrete slab described in 1 above. 8. The method for evaluating soundness of a concrete slab according to claim 1, wherein said dynamic deflection (δ) is a deflection caused by dynamic loading of a 15t and 20t constant load vehicle. .