This paper presents a methodology for probabilistic tsunami hazard analysis (PTHA) using radial basis function (RBF) network and quasi-Monte Carlo simulation (MCS). RBF network associated with tsunami intensity is obtained from the results of tsunami numerical simulations based on an experimental design, which can reduce the computational cost drastically. Quasi-MCS can be performed with fewer simulations than ordinary MCS even when estimating tsunami intensity corresponding to low exceedance probabilities. The proposed method is validated using the tsunami propagation simulation results. The contribution of the proposed methodology in terms of the computational cost associated with PTHA is discussed. In an illustrative example, the proposed method is applied to the risk estimation of tsunami disaster waste caused by the anticipated Nankai Trough earthquake in Mie Prefecture, Japan.

 In this paper, as a structure to integrate a high axial force subjected CFT column and the supported RC upper floor slab in a large underground box, a T-shaped joint is proposed, where the top end of the column is embedded in the floor slab. The loading capacity of the proposed joint is evaluated by means of a 3-D nonlinear FEM. This evaluation method is first developed and justified by analyzing the past reported results of the loading tests for a plus-shaped joint that integrates a penetrating CFT column and the supported RC intermediate floor slab. This proposed evaluation method reasonably estimates the damage area and its expanding extent under specific loading cases. The method can also derive the possibility of joint fracture taking place prior to the fracture of adjacent members, based on the change in rotating rigidity due to the rotation angle difference generated between the column axis and the slab axis. The established evaluation method is then applied to the proposed T-shaped joint, and it is confirmed to possess the required load capacity against the expected level of seismic forces without resulting in any preceding fracture or punching sheer fracture of the joint.

 For friction type high-strength bolt joints of steel bridges, holediameter up to 4.5 mm adding nominal diameter are allowed. If further margin is required, performance confirmation tests for the joints with larger oversized holes or slotted holes is required. On the other hand, according to other standards, it is permitted to apply oversized holes and slotted holes to friction joints by reducing the slip coefficient. In this study, we performed a slip strength test and a nonlinear FE analysis for high-strength bolt friction joints with zincrich paint on the contact surface in which plate thickness and yield strength of steel are parameters. On the basis of above discussions, we proposed a slip reduction coefficient for standard bolt holes when oversized holes or slotted holes are applied.

 This study proposed a method to restore the displacement waveform from the acceleration waveform when the train passes by utilizing the linear vibration theory. The proposed method replaces only the low frequency region affected by noise with a linear theoretical solution, although utilizes actual measurement data in the vicinity of the natural frequency where non-linearity such as concrete concrete member cracks and the influence of train / bridge interaction can be observed. The method identifies the only parameter of the ratio of uniaxial weight to modal stiffness. Numerical experiments clarified that the method can estimate the maximum displacement of bridge from acceleration in the error of about 5% or less, and the decrease in estimation accuracy was limited even when the dynamic characteristics of the bridge are unknown, when the standard deviation of noise is less than 0.005 m/s² and the train speed is more than 150km/h. Furthermore, the proposed method were applied to the acceleration monitoring data and it was shown that the displacement waveform can be restored from the acceleration waveform.

 Due to the damage caused by the 2011 off the Pacific coast of Tohoku Earthquake and the active faults of the 2016 Kumamoto Earthquake, it is becoming more important to anticipate actions that exceed the design. For situations that exceed expectations, it is important to consider recoverability and incorporate disaster mitigation perspectives that take into consideration reduction of impact and functional recovery into the design. If the bridge pier collapses, it will take an enormous amount of time to recover, so it is desirable to break the bearing at an appropriate time to ensure that the substructure is protected. Therefore, in this paper, we devised a countermeasure method for installing a member to control damage at the base of the steel pier, and verified its validity by experiments using a 1/8 reduced model specimen. We devised an FE model that is easy to apply to actual design for local buckling of steel pipes, cracks in internally filled concrete, contact phenomenon between anchors and control members, and performed time history response analysis that imitated actual bridges. The damage scenario for the action is shown. We devised an FE model that is easy to apply to actual design for local buckling of steel pipes, cracks in internally filled concrete, and contact phenomena between anchors and control members, and performed time history response analysis that imitated actual bridges. As a result, it was shown that the response due to the excess action was in line with the injury scenario.

 This study aims to improve accuracy of the road profile identification utilizing accelerations of a moving vehicle. There exist road profile identification methods: one identifies the vehicle force by dynamic programming and convert it into road profile and the other identifies road profile directly by pseudo inverse matrix. This study proposes a new method combining advantages of those two approaches that identifies road profile directly by means of a regularized least square minimization with dynamic programming. Accuracy of the proposed method is investigated by numerical simulations and a field experiment. Comparative investigations between the proposed method and the method based on Kalman filter to identify the road profile are also carried out. Observations showed that the proposed regularized least square minimization with dynamic programming method could be a practically useful method in IRI estimations utilizing acceleration responses of vehicle bounce motion.

 Recently, it is thought to be possible to use plastic moment M_p as the bending capacity of girders in conjunction with the revision of the specifications for highway bridges in 2017. Overseas specifications, such as LRFD and EC, permit to design the simple girders based on M_p as the bending capacity. However, in the design of continuous girders by LRFD and EC, there are cases in that the bending capacity has to be reduced under M_p considering the effects of moment redistribution due to non-linear behavior of negative bending sections. By contrast, the design method which utilize M_p as the bending capacity of girders has not been clarified in the specifications for highway bridges in Japan. Therefore, it is important to clarify the limit states of continuous composite girders in order to spread design of continuous composite girders considering M_p as the bending capacity. In this study, bending behaviors of three-span continuous composite with variation in span-ratio and distribution of bending stiffness are investigated theoretically. As a result, it is found that the bending capacity does not need to be reduced under M_p for all cases investigated in this study.

 Bolt axial force of high-strength bolted joints decreases due to deterioration. One of the conventional methods to evaluate the bolt axial force is ultrasonic testing. However, quantitative evaluation of the bolt axial force is controversial in terms of accuracy, and some problems remain for practical use. This study attempts the accurate evaluation of the bolt axial force by ultrasonic testing. The time zone analysis of the ultrasonic waves indicated that the waveform in the initial time zone includes bolt axial force information. The parasitic discrete wavelet transform (P-DWT) was applied to improve the evaluation accuracy. As a result of targeting bolts manufactured in the same lot, machine learning using linear regression evaluated the unknown bolt axial force within an error of 6% or less. Therefore, it was shown that the proposed method of this study corresponds to the existing bolt and can evaluate the bolt axial force with high accuracy.

 This paper shows the fatigue strength of lean duplex stainless steel butt welded joints. Stainless steel has greater corrosion resistance than carbon mild steel, and there are many types of stainless steel. Lean duplex stainless steel is inexpensive by reducing the rare element Ni and has higher tensile strength than that of SUS304. Although stainless steel is expected to reduce life cycle cost of steel bridges, its fatigue strength data is insufficient to establish the fatigue design method. Therefore, stainless steel is not widely accepted in road bridges in Japan, and the draft specification for stainless steel structures follows the standard for carbon steel structures. In this study, fatigue tests were carried out using butt welded joints made of SUS323L and SUS821L1, lean duplex stainless steel. The stress ratios used in the fatigue tests were zero and 0.3. The specimens were with unfinished weld toes or removed excess metal deposits. As a result, it was found that the fatigue strength of lean duplex stainless steel is higher than that of SUS304 under any conditions. All unfinished specimens fractured due to cracks from the weld toe. On the other hand, some flat specimens with removed excess metal deposits broke due to cracks from the welding metal. Finally, a fatigue strength curve applicable to lean duplex stainless steel butt welded joints was derived based on test results.

 In the maintenance of road bridges, it is important to properly diagnose the soundness of PC steel materials in PC structures in order to maintain the safety and reliability of long-term maintenance of bridges. In the evaluation of the soundness of PC steel materials, it is desired to improve the efficiency and sophistication of inspections, diagnoses, and countermeasures by utilizing non-destructive inspection methods. The purpose of this research is to improve the efficiency of maintenance work by sophisticating inspection and diagnosis technology for the magnetic flux leakage method, which is an effective non-destructive inspection technology for detecting fracture due to deterioration of PC steel. A test measurement vehicle equipped with a magnetizing device using a large electromagnet and a measurement unit was manufactured, and a running measurement experiment was conducted in a test running yard using a specimen. As a result, we have developed a technology that enables detection of fracture points in PC steel by performing magnetism, magnetic flux measurement, and image analysis processing in test measurements at a speed of 50 km/hr. This paper presents useful findings for expanding the application of the magnetic flux leakage method to vehicle running measurement.

 Many weathering steel bridges have been in service for more than 40 years, and therefore, it is necessary to clarify the fatigue strength of the weathering steel welding joints that have the protective rust layer. This study included corrosion property measurements, rust composition analyses, and fatigue tests of weathering steel welded joints that have been exposed to the atmosphere environment for 41 years. The rust layer thickness, corrosion pit depth, and weld toe radius tended to be similar to or relatively increase from those in the results of a study conducted after 25 years of exposure. Based on the rust composition, the presence of the protective rust layer in which the α-FeOOH layer was distributed near the interface with the steel surface was confirmed. The fatigue strength tended to be about the same as or larger than that after 25 years of exposure. Thus, the fatigue strength has been kept due to the corrosion reduction of corrosion progress by the protective rust that has been maintained after 25 years. In addition, a visual inspection and magnetic particle testing were conducted from the surface over the rust layer. Detecting the early stage of crack initiation was difficult due to the rust over the crack, but the crack became detectable after it had propagated up to certain lengths.

 In the weather risk managements, the extreme values of meteorological properties are statistically analyzed to plan the strategies against losses or damages. The asymmetric fluctuation and the heteroscedasticity are often encountered in their time histories, and the mixture of these natures complicates the statistics estimation. In order to accommodate this, a method employing the Box-Cox transform and the ARCH(1) model is proposed in this study, and is applied to the time histories of daily maximum wind speeds observed at the meteorological stations in 116 regions. The applicability of this method is investigated with a statistical test, and the heteroscedasticity in the time histories of daily maximum wind speeds is studied.

 Application of different contact faces in one bolted joints might allow labor-saving and accelerated works in some cases such as protection works of existing bridges and fabrication of box girders made of weathering steel without coating.

 In present study, bolted joints including different contact faces were targeted as a hybrid faying surfaces joint in which contact surface treatment for the base plates is different from corresponding that for splice plates (inorganic zinc-rich coatings), and 21 bolted joint specimens were used in bolt pretension test and slip test. This paper reports these results and compares degree of pretension loss and slip resistance in the hybrid faying surface joints with homogeneous (i.e. normal) joints. Finally, also based on previous research, the applicability and slip coefficient for designing of the hybrid faying surfaces joints are discussed.

 The characteristics of decrease of bolt pretension by relaxation differ depending on the type of contact surfaces. To enhance the safety of bolted joints, it is important to verify that the tension of high strength bolt is retained proper level even after relaxation. By investigating characteristics of decrease of bolt pretension by relaxation referring to past literatures about high strength bolted joints, we showed the characteristics of decrease of bolt tension by difference of contact surface type; painting, rust, rough surface, sprayed surface, and galvanization surface. In addition, this study also dealt with the effect of the initial tension of high strength bolt, the type of joint, the length of bolt, the thickness of paint.

 This paper is an experimental research study aimed at the future realization of tightening of the F10TW by the nut rotation method in the actual work. In this study, using a bolted joint test body with a pressure film type inorganic zinc rich paint on the contact surface, an introduction axial force test and a relaxation test were conducted to examine the nut rotation angle that can satisfy an appropriate bolt axial force. Also, the slip resistance was clarified.