Vibration complaints that are considered to be caused by vibration of a road bridge are roughly classified into those that arise immediately after the start of road use and those that occur after years of service. In the former case, a change in the new environment to a roadside resident due to construction of a road may be considered. In the latter case, there are cases where complaints continue to occur during the service period, but complaints may occur at certain times in recent highway roadside. In order to solve this problem, it is necessary to investigate the cause of the vibration generation and study the countermeasure, but the mechanism of the vibration generation factor is not sufficiently clarified. In this research, in order to elucidate this mechanism, we proposed an efficient measurement method to clarify the correlation between bridge vibration and house vibration, and showed an example on cause analysis of vibration complaints and propagation path. As a result, we clarified that the bridge and the house may resonate in the frequency band near the 12.5 Hz band.

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 It was confirmed from the recent earthquakes that fracture of set bolts for side block was a typical damage pattern for bridge bearings. Fractured set bolts or the body of the side block which was loosened due to the fracture of set bolts may fall down below the viaduct and may cause third-party damage to passing vehicles or to pedestrians. In this study, a new type of side block named as damage-controlled side block (DCSB) was proposed for highway bridges with the purpose of preventing third-party damage in a severe earthquake due to the falling of the damaged side block parts. A DCSB was designed with high ductility without brittle damage such as fracture of the stopper or the set bolts. Load-carrying capacity and plastic behavior of the DCSB were examined by static tests and shake table dynamic tests on full-scale specimens. As a result, it was concluded that the performance of the DCSB satisfied the requirements considered in the development. Furthermore, dynamic behavior of the superstructure with the varying of the plastic condition of the DCSB was investigated basing on the results of the shake table dynamic tests.

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 Decomposing an earthquake motion phase into the linear delay and fluctuation parts we investigated stochastic characteristics of phase difference of the fluctuation part. We took up the probability density characteristic of the mean phase gradient which is the quotient of a phase difference with respect to the concerned circular frequency interval. The probability density function of this mean phase gradient was uniquely defined for a rather wide range of circular frequency interval. It, moreover, had very unique distribution characteristics with thick tail and multiple crests. We proposed a method to express this distribution characteristics as a weighted sum of Levy-Flight probability density functions. We also developed an innovative algorithm to simulate the stochastic process obeying this peculiar probability density function by modifying the already proposed method for simulating the stochastic process which violates the central limit theorem.

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 Numerous cases of damage and deterioration of rubber bearings have been reported. The authors have conducted experimental studies on damage evaluation of the rubber bearings using Acoustic Emission (AE), which is a non-destruction inspection method. However, because elastic waves propagate in rubber with low velocity , there still remains some issues with the detection accuracy of AE due to those elastic waves.
 In this study, steel rods were inserted into natural rubber specimen and then a confirmation experiment of the detection accuracy of a peeling sound was conducted. The peeling sound was generated while the steel rods were extracted after only the tip was vulcanization-adhered. Regarding the distance between the tip of the steel rod and the rubber surface, seven patterns were prepared. Meanwhile, concerning the AE sensor, two types of resonance frequencies of 60 kHz and 150 kHz were prepared. In order to identify the position of the generated peeling sound, identification accuracy of the peeling position was confirmed using a three dimensional location analysis.
 The results showed that the peeling position inside the rubber can be determined with a high degree of accuracy.

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 A gust forecasting based on ARX (Autoregressive with Exogenous inputs) model which uses numerical weather prediction and on-site measurement as inputs was proposed and the model parameters were estimated by using non-parametric regression with forgetting factors. The prediction accuracy by using dynamically adaptive model was improved compared to the conventional static MOS (Model Output Statistics) model. It was also shown that the prediction accuracy of maximum gust improves by utilizing the numerical weather prediction with higher horizontal resolution. The predictability of the gust with the maximum wind speed larger than 15m/s was evaluated by using ROC (Receiver Operating Characteristic) curve and AUC (Area Under the Curve) and was improved by the proposed method.

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 Cracks may generate in buckle plates of steel railway bridges. The conventional measures against the crack have problems in terms of its workability and economy, and it is desirable to establish new measures. In this study, in consideration of establishing new measures, based on stress measurement and damage investigations on actual bridges and FEM analysis simulating them, the characteristics and cause of cracks in buckle plates of steel railway bridges was clarified. As a result, it was found that the cause of the crack generation was corrosion of the upper surface of buckle plates due to the loss of function of the waterproof layer, and corrosion-fatigue due to local out-of-plane bending stress near the attachment. In addition, based on the past studies, the evaluation on the tendency of generation of cracks by site in the buckle plate was attempted. As a result, it was found that in deck girders, if the waterproof layer did not function, there was a possibility that cracks would generate from the attachment, where was on the back side of the web of the lateral struts, whereas in other parts the possibility of cracking was low.

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 Fatigue cracks have been reported in I-beam ends of railway steel bridges, which occur at a lower end of an I-beam web. As a temporary countermeasure, the crack is typically repaired with a drilling hole at its tip, called a stop-hole method. In the cracked I-beam ends, however, the effect of life extension due to a stop-hole has not been clearly evaluated yet. In this study, the life extension of cracked I-beams by applying a stop-hole was investigated through fatigue tests using an actual I-beam bridge removed from the field. And also, in order to make sure local stress distribution around the stop-hole in the test, finite element analyses were performed. As a result, it was proven that the fatigue life of the repaired I-beam can be predicted from the local stress range at the stop-hole edge. Furthermore, it was revealed that the maximum stress along a stop-hole tends to decrease as a crack becomes long, meaning that the effect of the stop-hole varies depending on crack length.

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 One of the complaints due to traffic vibrations generated from highway bridges is a low-frequency sound. The authors focused on this phenomenon to analyze the occurrence and the component where the low-frequency sound is generated. Analyzed vibration modes were vertical primary mode, which has a lot of measured cases, and higher-order vibration mode, which includes the vibration of the out-of-plane of the lower floor slab. Bridges considered for the study were the multiple girders and the two main-girder. By analyzing the measurement data on vibration and low frequency sound, the frequency band to cause complaint has been revealed. In addition, the vibration mode of the bridge corresponds to the frequency band causing complaints were analyzed. Furthermore, by analyzing the relationship between the vehicle position and the low-frequency sound, differences were found in the causes of each frequency. Then, a numerical analysis using a 3D FEM model was conducted to reproduce the analysis results from the measured data. It was possible to grasp the vibration distribution shape generating complaints and the general behavior of the bridges.

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 Torshear type high strength bolts are widely used to bolted joints in steel bridges. It is known that their bolts vary widely of bolt axial force by temperature. However, characteristics of bolt axial force is not clarified. In this paper, we have investigated the 10385 of bolt axial forces on the basis of the mill sheet date and bolt-tightening tests date in order to clarify bolt axial force on torshear type high strength bolts of 22 mm diameter. We also have investigated the mechanical properties of their bolts.

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