This paper focuses on historical structures constructed with modern structures and construction methods, such as brick, concrete, and steel structures. First, “what constitutes value?” that is, what should be preserved, revitalized, or reused, is outlined. Then the practical difficulties are explained, and finally, the technologies required for repair and restoration are detailed. This is expected to encourage the active participation of such as general civil engineers and building engineers.

Close-up visual inspection by inspection technicians of infrastructures has various problems such as ensuring safety and high cost. Inspections using digital images are highly expected to improve efficiency by shortening the construction period, reducing costs, and ensuring safety. Therefore, the authors showed the relationship between the pixel resolution and crack width of an image suitable for inspection, and the optimum method for making an object threedimensional by SfM / MVS, and explained the effectiveness of inspection using digital images. The authors also showed the effectiveness of inspections using robot technology such as drones, and explained the points of interest in selecting robot technology and the procedure for formulating an implementation plan.

The strain visualization device is a strain measurement sensor developed for long-term monitoring of infrastructure. Since the strain detection position of the strain visualization device is structurally separated from the member surface, the distance from the neutral axis is larger than that of the member surface, and the strain value is large when strain measurement of members with bending deformation. Therefore, while showing the correction method, it was experimentally verified that the strain visualization device can be applied to strain measurement of members with bending deformation by adding the correction. In addition, the strain visualization device was applied to strain measurement of the loading test of an actual bridge, and its applicability to an actual structure with bending deformation was proved.

Many lighthouses in East Japan suffered extensive damage in the 2011 Great East Japan Earthquake. The lighthouse dealt with in this paper is one of these damaged lighthouses. A careful investigation is required to estimate the long-term behaviour as well as the seismic vulnerability. The present study deals with the dynamic test, dynamic identification and long-term structural health monitoring of the lighthouse before and after carbon fiber reinforcement. From the results of dynamic tests, the fundamental frequencies, natural modes and damping ratios are identified by Stochastic Subspace Identification. The result of long-term structural health monitoring is discussed in this paper.

This paper presents an experimental and analytical study on how to identify the deterioration points of bridges using the rate of change of deflection influence lines and deflection curves. In the experiment using aluminum H-beams, the stiffness was changed by attaching aluminum steel plates instead of deteriorating the structural members. Although there was little difference in the natural frequencies of the two structures due to the change in stiffness, it was confirmed that the change rate of the deflection influence line could be used to identify the location of the stiffness change. In addition, it was found that the rate of change of the deflection curve obtained from the experimental results and the elastic analysis results of the two-dimensional FE analysis could be used to identify the location of shear cracks in the loading test of RC beams with shear failure precedence.

This study proposes the method for estimating the amount of corrosion of rebar in concrete from the surface shape measurement of reinforced concrete by using a 3D scanner. We focused on the surface swelling caused by the corrosion of the rebar in concrete, and found the relationship between the change in surface shape and the amount of corrosion of the rebar. As a result, we confirmed that corrosion could not be visually confirmed by 3D measurement, and showed the possibility that amount of corrosion of rebar could be estimated from the amount of surface swelling. We also confirmed that these relationships differ depending on the corrosive environment.

In this study, in order to verify the effectiveness of the flaking inspection by the combination of infrared thermography and ultrasonic testing technique method which seems to be able to efficiently inspect the flaking of concrete, this paper compares and evaluates flaking detectability and quantitative evaluation experimentally using a concrete test piece with artificial defect. As the result, the infrared thermography was effective as a screening technique of the flaking, because it can quickly inspect the wide range, and the ultrasonic testing technique method seemed to be effective as a detailed inspection technique as a depth measuring means of the defect detected as the flaking by the screening.

We are currently developing a mobile scaffolding device that can dodge the piers of bridges without dismantling the scaffold when moving between spans to improve efficiency and safety in bridge inspections. The mobile scaffolding device treated in this paper is split in the center of the device when it crosses the piers. In this process, the mobile scaffold is cantilevered and poses a danger to the workers on board. Therefore, we implemented horizontal holding control by wire reeling to keep the mobile scaffold horizontal. However, mechanical analysis and investigation of the mobile scaffold device have been insufficient in the previous studies. Especially, the wire constraint position corresponds to the arm length of the moment generated by the wire tension. Therefore, it is inferred that the wire constraint position has effects on the horizontal holding performance. Therefore, in this paper, several candidates for the wire constraint position were obtained, and the horizontal holding performance was compared and verified at each position. As a result, it was found that by setting the x-coordinate of the wire constraint position close to the wire reeling mechanism and the ycoordinate at the bottom of the scaffolding, highly stable horizontal holding control can be achieved with small wire tension.

Deformation behaviors of aluminum alloy A3003 under constant high temperature and under cooling from high temperature were precisely evaluated by digital image correlation (DIC) method. Tensile testing system equipped with a furnace which can control heating and cooling at an arbitrary rate was developed. DIC analysis for 3D deformation of necked region in tensile specimen enabled evaluation of the true stress-true strain curves. True stress-true strain curves under constant temperature were accurately described by constitutive equations which express the logarithm of true stress as the function of the squared logarithm of true strain. FEM analysis of the tensile test revealed that the stress distribution in the localized necking region became non-uniform when the strain exceeded 0.1. Therefore, it is considered that the true constitutive equation of the material cannot be obtained only from the stress-strain curve defined by the surface deformation and strain measured by DIC method. Under cooling from high temperature, higher resistance was measured than that predicted from true stress-true strain curves under constant temperature. It was suggested that consideration for time-dependency of true stress-true strain curves is necessary for precise simulation of residual stresses and strains on casting and multi-material joining processes.

Recently, carbon fiber reinforced thermoplastics (CFRTP) were used in the automobile industry because of their moldability, recyclability, and high toughness. CFRTP is consisted with the carbon fiber and matrix resins. Usually, matrix resin has their crystallinity that easily change their mechanical properties, and it also have degradation properties such as thermal degradation. In this study, one of the mechanical properties, the dynamic viscoelastic properties of CFRTP with the matrix of PA6 were investigated. The materials were heat-treated at crystallization temperature 185ºC for 1, 3, 10, 30 hours. Heat treated materials were investigated with DMA, FT-IR spectrum, and X-ray diffraction to understand their dynamic viscoelastic properties, crystal conditions, and amount of thermal degradation. It was revealed that the heat treatment at 185 ºC reduced Tg and E' due to the change in the crystal structure of PA6 in CFRTP from αtype to γ-type. And it was clarified that activation energy obtained from making the master curve of storage modulus in higher temperature region was mainly depended on not the crystallinity but the amount of thermal degradation.

Automobile collision safety for the accident between the vehicles at the first collision has advanced by experimental, computational and theoretical evaluation. For more improvement of the collision safety, it is necessary to understand the automobile motion after primary collision to protect the driver, pedestrian and worker from another accident occurred by subsequence collision. However, collision experiment and safety measure, which is considered to secondary collision, are not sufficiently carried out, since the vehicle motion after the first collision is complicated and difficult to predict, although theoretical analysis has been reported. In previous paper, we reported the effect of wheel rotation and collision-position on the collided vehicle behavior after side-collision. In this study, in order to evaluate the influence of collision-angle, which represents the angle of motion direction between two vehicles, for collided vehicle motion after collision, we carried out the side-collision experiment with simple vehicle model on the difference collisionangle, and analyzed the trajectory of struck-vehicle motion. As the results, the collision-angle influences in the vehicle rotation and moving distance, and in the rear-side collision, re-collision is caused at all angles.

Thermal storage techniques that use phase-change materials have recently attracted increased attention. Erythritol, a kind of sugar alcohol and a phase change material, is viable for thermal storage and has both higher thermal storage capacity and phase-change temperature than those of its widely used counterpart, n-alkane. Micro-encapsulation of these phase-change materials results in an increase of both the surface area per unit volume and the transportability of the particles in the form of a slurry or emulsion. In this study we developed silica-covered erythritol microcapsules. These microcapsules are obtained by sol-gel reaction of tetraethoxysilane (TEOS) which yields silica by sol-gel process at interface between the erythritol particle and a TEOS solution. Most of the microcapsules had sizes of less than 50 μm with the average size being 24.1 μm. Moreover, silica-covered erythritol microcapsules could stably store waste heat at ordinary temperatures and pressures, and with the aid of physical stimuli, use this stored heat. Therefore, these microcapsules are potentially viable for use in circulating heat carriers and sources, and have significant potential for the effective utilization of energy.

Reduction of CO₂ emission from diesel engine is necessary because of requirement in atmospheric environment. To reduce diesel fuel consumption of a general purpose diesel engine, blend alcohol composed of 87% ethyl alcohol was supplied with two methods. One is a mixing of the blend alcohol with diesel fuel and the other is a port injection of the blend alcohol. Engine performance was measured with combustion analysis based on cylinder pressure and a dynamometer. The mixing of the blend alcohol with diesel fuel was limited less than 7% because of separation and boiling resistance. The port injection of the blend alcohol was limited about 25% in fuel by means of knocking during engine operations. In comparison with diesel fuel, combustion is faster with higher thermal efficiency in the former case and combustion is delay in the latter case without any reduction on thermal efficiency. The port injection is better than the mixing to reduce diesel fuel consumption.