Fuji Engineering Co.

Ōsaka, Japan

Fuji Engineering Co.

Ōsaka, Japan
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Imagawa Y.,Fuji Engineering Co. | Ohyama O.,Osaka Institute of Technology | Kurita A.,Osaka Institute of Technology
Structural Engineering International: Journal of the International Association for Bridge and Structural Engineering (IABSE) | Year: 2012

Many examples of a bridge damaged due to accidental or incendiary fire heating up the bridge from below have been reported. When steel and concrete composite girder bridges are exposed to fire, it is important to understand the progression of damage to the shear connections. However, determination of the level of damage to the shear connection in experimental tests is a challenge. Furthermore, the post fire performance of the shear connection is not clear yet. To better understand the mechanical properties of the shear stud during and after fire, the authors conducted three different push-out tests of heated studs, in which the fire temperature varied from 300 to 700°C over a period of 90 min. From the results of the static push-out tests conducted after heating, it was found that the maximum shear resistance of shear studs is marginally affected by the heating, but the slip constant was decreased remarkably in proportion to the heating temperature. Furthermore, the fatigue strength of shear studs showed remarkable decrease due to the undesirable slip behavior.


Patent
Fuji Engineering Co., WEST NIPPON EXPRESSWAY COMPANY Ltd and Fujigiken Co. | Date: 2012-12-17

The blasting material includes abrasives, and water in the range of 5 to 30 mass % both inclusive relative to a mass of the abrasives, the abrasives being prepared in advance such that all of the abrasives are uniformly wet.


Patent
Fuji Engineering Co., WEST NIPPON EXPRESSWAY COMPANY Ltd and Fujigiken Co. | Date: 2012-12-17

The invention provides a sealer to be used for a bolt including a sprayed preservative coating coated onto at least a threaded portion. The sealer contains a wax therein in the range of 1 to 10 mass % both inclusive.


Patent
Fujigiken Co., WEST NIPPON EXPRESSWAY COMPANY Ltd and Fuji Engineering Co. | Date: 2012-12-17

A method of carrying out post-treatment to a sprayed coating includes spraying aluminum-containing material onto a surface of a steel for forming a sprayed coating on the steel, and coating electrolytic aqueous solution or water base paint containing electrolytic aqueous solution therein onto the sprayed coating.


Patent
Fuji Engineering Co., WEST NIPPON EXPRESSWAY COMPANY Ltd and Fujigiken Co. | Date: 2012-12-17

The plasma spraying apparatus includes a cathode, a first gas nozzle defining a first gas path between the cathode and itself, a second gas nozzle defining a second gas path between the first gas nozzle and itself, and a third gas nozzle disposed between the first and second gas nozzles to define a third gas path between the first and second gas paths. A wire is disposed at a distal end thereof in front of a nozzle opening of the second gas nozzle. A first gas sprayed through the first gas nozzle is turned into plasma flame, which melts the wire into droplets, and the droplets are sprayed onto a target by a second gas sprayed through the second gas nozzle. The third gas absorbs heat from the plasma flame to thereby turn into a high-temperature gas flow externally of the plasma flame.


Patent
Fuji Engineering Co., WEST NIPPON EXPRESSWAY COMPANY Ltd and Fujigiken Co. | Date: 2012-12-17

The plasma spraying apparatus includes a cathode, a first gas nozzle surrounding a head of the cathode therewith to form a first gas path outside of the cathode, and a second gas nozzle surrounding the first gas nozzle therewith to form a second gas path outside of the first gas nozzle. The second gas nozzle is formed with a wire path through which a wire is inserted such that a distal end of the wire is disposed in front of a nozzle opening of the second gas nozzle. The wire path has a substantially rectangular cross-section having a longer side extending in a direction in which the plasma flame extends, the wire path causing the wire to bend within elastic limit of the wire.


Fukada S.,Kanazawa University | Kaneishi Y.,West Nippon Expressway Co. | Hama H.,Fuji Engineering Co. | Okada H.,Fuji Engineering Co.
INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering: Improving the World Through Noise Control | Year: 2014

Recently, increasingly heavy traffic flow volumes have led to fatigue damage in the deck and pavement of bridges. Heavy trucks are a major contributor to such damage, causing environmental vibration problems such as infrasound and ground vibration. These vibrations are known to be transmitted through bridges to nearby houses. This study investigated bridges that caused such problems in nearby houses. Bridge repairs were performed to solve these problems. The improvement in infrasound and ground vibration upon bridge repair was investigated using a test truck and ordinary trucks. The ground vibration of the abutment with frequencies of 10 Hz or more decreased greatly as did the ground vibration outside the houses. Furthermore, infrasound with frequencies of 10-20 Hz decreased.


Fukada S.,Kanazawa University | Hama H.,Fuji Engineering Co. | Usui K.,West Nippon Expressway Co. | Agawa K.,West Nippon Expressway Co.
Advances in Environmental Vibration - Proceedings of the 5th International Symposium on Environmental Vibration, ISEV 2011 | Year: 2011

At the houses near-the bridge, there have been complaints aborit a rattling soimd and /or complaints about, mental and physical discomfort caused by the infrasound, which is radiated from the highway bridge under moving vehicles. General truck in Japan with rear leaf suspension have frecruencies of about 3Hz. Also, the frequencies of the tire spring vibration are about 10-20Hz. The steel continuous bridges with middle span length have the vibration modes with the same phase in each span and with the secondary mode shape. These bridge vibration modes are related to the suspension spring vibration and/or the tire spring vibration of the trucks. This study clarifies the relation of the infrasound, the vibration of the trucks, and the bridge vibration by using several experimental results.


Fukada S.,Kanazawa University | Usui K.,Fuji Engineering Co. | Yoshimura T.,Kobe Steel | Okada T.,Kobe Steel | And 2 more authors.
Journal of Civil Structural Health Monitoring | Year: 2012

An environmental vibration problem occurred at a house near a highway bridge on soft ground. Vibration experiments with a test truck were performed to investigate the cause of the problem and the vibration characteristics of the bridge and house. Experimental results showed that the house was resonating with the bridge. As a measure to reduce vibration, viscoelastic dampers were installed at the ends of the bridge girders. The effectiveness of this measure was evaluated by comparing the data gathered before and after the installation of the dampers using ordinary trucks running over the bridge. Moreover, a dynamic response analysis was carried out to investigate the vibration reduction as a function of the number of installed dampers as well as the various analytical conditions employed. Simulation results showed that the vibration reduction depends on the boundary condition, running position, and torsion modes that have a coupling vibration between the superstructure and the piers. © 2012 Springer-Verlag.


Fukada S.,Kanazawa University | Hama H.,Fuji Engineering Co. | Usui K.,Fuji Engineering Co.
Journal of Modern Transportation | Year: 2012

As heavy trucks pass over highway bridges, bridge vibration occurs and generates infrasound. General trucks in Japan with rear leaf suspension have whole body vibration (suspension spring vibration) frequencies of about 3 Hz. Also, the frequencies of the wheel vibration (tire spring vibration) are about 10-20 Hz. The continuous steel highway bridges with middle span length have vibration modes with the same phase in each span at the frequencies of about 3 Hz and also have those with the secondary mode shape at the frequencies of about 10-20 Hz. Truck vibrations and bridge vibrations are closely related. In this work, vibration tests are conducted using a heavy test truck for two cases of infrasound complaints in order to investigate the relation between the continuous steel bridge vibration modes generated by the vibration of moving heavy trucks and its infrasound characteristics. As a result of the examination, two types of bridge vibration modes are caused by the vibrations of a moving heavy truck. Moreover, the bending vibration modes with the same phase in each span have the most powerful infrasound pressure, since each span vibrates with the same phase. Two countermeasures, including viscoelastic damper at the end of the girders and extended deck method, are proposed to reduce the amplitude of bridge vibration and its infrasound. © 2012 JMT. All rights reserved.

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