第九回道路橋床版シンポジウム論文報告集

土木学会

論文
論文

SELF-PROPELLED IMPACT VIBRATIONEQUIPMENT FOR THE UTILIZATION OF
INSPECTION OF BRIDGE DECKNga Thu NGUYEN1, Hiroshi MASUYA2, Chen XU3, Hiromitsu KAII4,Takafumi YAMAGUCHI1 and Hiroshi YOKOYAMA5
1 Kanazawa University, Graduate school of Natural Science and Technology, Division of enviaronmental Design(Kakuma-machi, Kanazawa 920-1192, Japan )2 Kanazawa University, Institute of Science and Engineering, Faculty of Environmental Design(Kakuma-machi, Kanazawa 920-1192, Japan )masuya@se.kanazawa-u.ac.jp
3 Tongji University, College of Civil Engineering(1239 Siping Rd, Shanghai, 200092, China)
xuchenprc@tongji.edu.cn
4
Toyama prefectural government, Toyama center of Civil Engineering(Funabashikitamachi 1-11, Toyama 930-0096, Japan )5
Nippon Engineering Consultants Co., Institute of Technology of Infrastructure(Komagome 3-23-1, Toshimaku, Tokyo 170-0003, Japan)
yokoyama_hiroshi@ne-con.co.jp

A lot of fatigue damage of reinforced concrete slabs of bridges have been seen in Japan. Therefore, themaintenance of bridges is an important issue．In this study, SIVE (Self-propelled Impact Vibration Equipment) was developed to evaluate the deterioration degree of slab simply and rationally. SIVE can makesmall turns by a simple operation using hands. The equipment also can change the mass of a falling weight,
height and rubber condition used as cushion system. Several investigation concerning those parameters
were done and concretely shown
Key Words : Bridge deck, Impact vibration, Degradation diagnosis

1. INTRODUCTION
Generally a certain equipment which has a featureof mobility and enough power to carry out a field teston an entire bridge or a part of bridge, such as a slabdeck, is required. Therefore, an equipment(SIVE)
was developed to fulfill such requirements.
The overview of SIVE is shown in Figure 1. It iseasier to set SIVE at any point by a simple operationcompared with FWD car systems. This equipment
consists of two large parts which are a forklift truck
and an impact occurrence equipment. Electric truck
works by the battery DC 24 volt and supplies necessary power to the impact occurrence equipment, themeasuring equipment and personal computer. Theoccurrence equipment consists of the hoist lifting aweight, steel weight, rubber buffer, load cell andloading plate. The equipment can change the mass ofa falling weight, a falling height and a rubber cushionused in cushion system. The maximum falling heightis 0.3 m and the maximum mass of weight is 220 kg.
The capacities of energy and momentum are 0.65 kJ,
0.44 kNs respectively.

It is well known that almost all highway bridges inJapan were built in period 1965-1980 when the Japanese economy grew up rapidly. Currently, there are asignificant number of bridges nearly 50 years of age,
it is recognized that those bridges have to be maintained(1,2,3). The fatigue damage of reinforced concrete slabs have been seen not only in Japan but also
in developing countries, such as Vietnam, whichmight be serious problems in future . In this study,
SIVE ( Self -propelled impact vibration equipment)
was developed to evaluate the deterioration of slab
simply and rationally. This equipment can change themass of falling weight, a height and a rubber condition used as cushion system. When SIVE is used atthe site, generally, proper impact force, momentumand duration of impact force are required dependingon the scale of objective structure. In this study, impact tests for series of rubber buffer were perfomed,
characteristics of impact force were shown and summarized.

2. DEVERLOPMENT OF SIVE
1- 89 -Type A and B There were 29 and 15 of rubbercones were arranged in Type A and B respectively.
This type of rubber cone (rubber buffer KFDF-51,
Tokyo sokki kenkyujo co. ltd) is normal rubber, 48
mm of height, 40 mm of diameter . Type D and E are
low rebound rubber (Hanenaite, Naigai rubber industry co. ltd.) with the height is 32 mm and the diameteris 26.09 mm. In addition, type C arranged by 6 low
rebound triangle rubbers.
Experiments were conducted with a plate that has
detail of dimensions (Figure 3). The plate was setup
in two support, loading plate was set in the center ofplate. Displacement of the center point of the plate
was measured by a displacement meter (CDP5, Tokyo sokki kenkyujo co. ltd.).
In the same conditions and five types of rubber,data were collected from equipment built-in load cell.
Velocities and displacements were got by using numerical integrations.

Fig.1: Overview of SIVE (Self -propelled Impact VibrationEquipment)

3. METHOD OF EXPERIMENTThe series of impact experiment using SIVE weredone. Table 1 shows the list of experiments. In thisseries of experiment, the 220 kg mass of weight isused three times for each case. The figure 2 shows thearrangement of 5 types of rubber cushion for choosing the suitable rubber to control the maximum forcesand duration of impact

PDisplacement Meter
800
1000

250

100

Type B

2501000500

Type A

Type C1000

Fig.3: Test specimen

Type D

Type E
Fig.2: Rubber buffer
Table 1: List of experiments

Cushion
TypeA
B
C
DE

Mass of weight
Mw (kg)
220
220
220
220
220

Falling height
Hf (m)
0.05 to 0.30
0.05 to 0.30
0.05 to 0.30
0.05 to 0.30
0.05 to 0.30
2- 90 -Collision energy
Eini (kJ)
0.11 to 0.66
0.11 to 0.66
0.11 to 0.66
0.11 to 0.66
0.11 to 0.66

Momentum
Mini (kNs)
0.22 to 0.53
0.22 to 0.53
0.22 to 0.53
0.22 to 0.53
0.22 to 0.53100Force(kN)

90
80
70
60
50
4030
20
100-100.29

displacement meters and calculated based on acceleration were shown in figure 4d. It became clear thatthe displacement calculated from acceleration at thecenter point is in good agreement with the value bydisplacement meter. The ratio between them was approximately 1.0.
0.3

0.31

1000.32

Time(s)Force (kN)(a) Impact force
200Acceleration

10000.29

Type A80

Type B

60

Type C

40

Type D20Type E

00.3

0.31

00.32

0.1

-1000.4(a) Impact force
Duration of impact(s)Time (s)(b) Acceleration
0.6
0.40.2

Velocity

0.3

0.06

-200

00.29
-0.20.2Height (m)0.05Type A

0.04

Type B

0.03

Type C

0.02

Type D0.01

Type E

00

0.3

0.31

0.32

0.1

0.2
Height (m)

0.3

0.4

(b) Duration of impact
Fig.5: First impact force and duration of impact-0.4Time(s)Figure 5 shows the maximum force and durationof impact of different falling heights on all type ofcushions. It shows that the maximum force has monotonously increased with the rise of falling heights
in all type of cushions. Cushion Type B,C,D and E
had experienced some dramatic changes in durationof impact while cushion Type A had slight one. Different cushions differs in duration of impact andforces. The largest impact force was found in type Ecushion. Duration of impact, on the other hand, hasdecreased along the falling heights.
Figure 6 indicates the sample of impulse by thefirst impact of two typical type of cushion A and D.
The maximum force and the duration of force are approximately 90 kN and 0.03 s in both types. It can beseen that rebound is large in Type A (normal rubber)and small in Type D (low rebound rubber).
Table 2 provides the overall view of displacement.
The difference between the calculated displacements
and the true value is small in all case except the one
with a low falling height 0.05 m. Displacements experienced the same trend of increase in all case withthe rise of falling heights
It is generally suggest that it was so important tocontrol the maximum force, duration of force and lessrebound of falling weight for better pursuit of experiment at site.

Displacement(mm)(c) Velocity-0.50.29

0.3

0.31

0.32

-1.5
Calculated Dis

Mesuarmed Dis-2.5

Time(s)(d) Displacement
Fig.4: Example of impact force, acceleration, velocity anddisplacements (Mw=220 kg, Hf=0.3 m, Cushion Type D)

4. RESULTS OF EXPERIMENTS
Figure 4a and 4b show the time course impact force
from 0.3 m height in case of type D rubber and theacceleration data. The first impact is the most important for the dynamic behavior of structure. Thus
the first impact should be forcused. In this type ofcushion, the impact force reached the peak at about
80 kN in only 0.02 s. With rebound rubber, the rebound of falling weight seems to be reduced. In addition, the velocity was calculated from the acceleration in figure 4c. The displacements measured by the3- 91 -

Table 2: Relationship between calculated displacements and measuarmed displacements
Height (m)DCmax (mm)Dmmax (mm)DCmax/ Dmmax
DCmax (mm)Dmmax (mm)DCmax/ Dmmax
DCmax (mm)Dmmax (mm)DCmax/ Dmmax
DCmax (mm)Dmmax (mm)DCmax/ Dmmax
DCmax (mm)Dmmax (mm)DCmax/ Dmmax
DCmax (mm)Dmmax (mm)DCmax/ Dmmax

0.05

0.1

0.15

0.2

0.25

0.3Type A-0.579-0.5521.049-0.815-0.8880.918-1.092-1.1150.980-1.311-1.3051.005-1.620-1.6031.011-1.947-1.840Type B-0.483-0.4251.136-0.812-0.743
1.093-1.115-1.0681.044-1.487-1.4601.019-1.870-1.8691.000-2.241-2.268

Type C-0.399-0.3451.158-0.926-0.7711.201-1.252-1.1541.084-1.616-1.5531.041-2.001-1.8561.078-2.358-2.276

Type D-0.396-0.358-1.106-0.648-0.6201.045-0.868-0.8031.081-1.160-1.1471.012-1.576-1.5671.006-1.927-1.869Type E-0.285-0.3050.934-0.068-0.0681.004-1.033-1.0350.998-1.705-1.7210.990-1.985-1.9861.000-2.569-2.462

1.058

0.988

1.036

1.031

1.044

In this study, SIVE ( Self-propelled Impact Vibration Equipment) was developed for the bridge deck
damage inspection. The conclusion are summarized
as follows.
1) The maximum forces and durations of impact bySIVE were concretely shown for 5 types rubbercushions.
2) Generation of ideal single impact is possible,
when low rebound rubber cushion (Type C, D orE) is used.
3) The maximum force can be controlled bellow
100 kN and duration of impact are approximately
0.2 s to 0.5 s.
4) It is possible to calculate the accurate displacement by the acceleration measured in SIVE.
With the accuracy we will us SIVE for the measurement of displacements at actual site in the future.

Mw=220kg, Hf=0.3m, Cushion Type A

0.8
Impulse (kNs)

100

Impulse (kNs)
Initial momentum
Force(kN)

80

0.6

60

0.4

400.2

2000.27

0.28

0.29

0.3

0.31

Force(kN)

100.32

Time(s)(a) Type A
Mw=220kg, Hf=0.3m, Cushion Type D

Impulse (kNs)

0.8

Impulse (kNs)
Initial momentum
Force

100
80

0.6

60

0.4

400.2

2000.28

0.29

0.3
0.31
Time(s)0.32

ACKNOWLEDGMENT: This study had been doneby the support of Cross-ministerial Strategic Innovation Promotion Program (SIP). Here, Authors represent the gratitude

Force(kN)

100.33

REFERENCES1)(a) Type D
Fig.6: Sample of impulse and force2)
3)

5. CONCLUSION

4- 92 -Japan road association: Design specifications for steel highway bridges/Production specifications for steel highway
bridge, Gihoudo Co. Ltd., 1956.
Japan road association: Specifications for highway bridges
part2 steel bridges ver. 2002, Maruzen Co. Ltd., 2002.
Masuya, H., Yokoyama, H., Sekiguchi, M., and Xu,C.
(2015). “ Study on impact behavior of fatigue deteriorated
reinforced concrete slab by finite element method” Proceedings of 11th International Conference on Shock & Impact
Loads on Structures, 267-272(Received July 18,2016)