This study aims to analyze the influence of observed river channel conditions on inundation simulation in terms of discharge within a river channel and inundation area and depth over a floodplain. The target area is the Lower Mekong River Basin, which suffered from severe floods in 2000 and 2011. First, measurement using an acoustic Doppler current profiler is conducted to understand the longitudinal distribution of cross-sectional shapes and roughness change during a flood in a river channel. Based on the observation results, inundation simulation with the Rainfall-Runoff-Inundation model is conducted. The calculation results show that the reproducibility of discharge improves by taking the longitudinal distribution of the width and depth of the river reach into consideration, and that the water depth over the floodplain has a high sensitivity to both cross-sectional shapes and roughness change during the flood.

The New Waste Disposal Area is the final disposal site in Tokyo Port to dispose of the wastes such as municipal/industrial wastes, construction waste soil and dredged soil. Therefore, to utilize this area for a long time, measures for expanding its capacity or reducing the volume of wastes have been taken. The work for volume reduction of disposed clayey soils was carried out with the vacuum consolidation method at block C of the area to prolong its service life. In this project, the prefabricated vertical drains (PVDs) with a width of 150 mm and a thickness of 3.9 mm were used. The PVDs were installed in the clay layer at the average elevations of +1.5 to -33.8 m with a square spacing of 1.8 m with the negative pressure of 65kN/m2, which is equal to the consolidation pressure increment, was applied for 310 days. The trial period began in 2005 and the main project period started in 2007 and was completed in 2015. During this period, work was performed on 383,000 m2; the mean settlement volume was 5.13 m and the volume obtained through settlement consolidation was 2,167,000 m3. This means that the service life of this disposal area was extended for 2.3 years. This paper provides the general overview of this project with a focus on geotechnical engineering.

Progress has been made in the diversification and repeated reuse of reclaimed asphalt pavement (RAP) in recent years. However, evaluating the quality of RAP containing polymer-modified asphalt (RAPm) has been difficult, and no method has been established for its reuse as hot mix asphalt. We have been developing recycling technology to restore RAP to the original condition of each material by separating it into aggregate and asphalt using hot water, and have succeeded in restoring aggregate from RAP containing straight (nonmodified) asphalt (RAPs). In this paper, we examine the recovery of aggregate from RAPm using hot water and the restoration of asphalt quality using high-temperature, high-pressure water. This technology can be applied to RAPm to rejuvenate asphalt.

Estimating the life of rubber marine fender (fender) is an important concern in the maintenance of a port facility. From the supply record of the Circular-Shaped Buckling (CSB) fender with panel contact, the actual service life was from 15 to 35 years. The compression tests of the fenders returned from ports showed that the reaction forces increased moderately due to the years in service. Other than some visible signs such as cracks and deformations, invisible signs of aging including uneven buckling, increased reaction force, and the growth of cracks were observed. The material tests results indicated that the deterioration of physical properties were limited to the rubber surface; the center of rubber bodies were still considered to be elastic and flexible. The performance in the first compression cycle of the test showed that the used fender exhibited a higher reaction force than the value stated in the catalogue - that is a value equivalent to the average of the second and third compression cycles. This increased reaction force during the first compression cycle (after a long interval from it's last compression cycle), for example, if used as inventory stock, could potentially be a concern to the berth structure and/or the vessel's hull.

Although the importance of understanding the diverse values of participants in global infrastructure projects has been increasingly recognized, research on methods to assess moral values in such contexts is still lacking. This article proposes a method for extracting context-specific moral values in three steps: (1) vignette development, (2) interviews, and (3) data analysis. The article illustrates how the method can be applied to understand the way project members make and rationalize their decisions when faced with moral trade-offs in the management of infrastructure projects.

The case method, which has been used in other fields such as business administration, is gaining attention as an approach to developing human resources capable of crisis management in the event of a large-scale disaster. This paper reports on the development of learning materials that contain examples of actions taken by infrastructure administrators and construction firms during the Great East Japan Earthquake. This paper also considers methods of using such cases in simulation classes and describes studies using the case method in on-the-job training to develop disaster-response management capabilities. Many institutions are working on passing down lessons learned from disasters to the next generation. It is believed that providing specific approaches for human resource development will not only enhance the capability of responding to expected large-scale disasters but also secure and develop human resources, one of the key issues in the civil engineering field.

To investigate the safety of structures for future mega-thrust earthquakes, it is important to develop a reliable source model for the simulation of strong ground motions from such earthquakes. Nozu et al. (2012) developed a source model called the “SPGA model” for the purpose of simulating strong ground motions from mega-thrust earthquakes in the frequency range relevant to structural damage. It is, however, necessary to further investigate the reliability of the source model especially by using records from dense strong-motion arrays such as the Small-Titan. In this article, the SPGA model is applied to the records of the Small-Titan and its performance is discussed.

Post-Disaster Community Redevelopment is ongoing in Onagawa, Miyagi, for the reconstruction of the town that lost 8%

Minami-Gamo Wastewater Treatment Plant (MGWTTP) is the most important facility for the Sendai City sewerage system. The plant treats about 70 percent of the municipal wastewater from Sendai City. On March 11th, 2011, the plant was devastated by the Great East Japan Earthquake and the ensuing tsunami. Its foundation was heavily damaged. Sedimentation and aeration tanks were bent. Most of the mechanical and electrical equipment became flooded by seawater and were washed away. MGWTTP completely lost its wastewater treatment function. Due to this damage, the Sendai City Government decided that MGWTTP could not be repaired and instead should be rebuilt as a brand-new wastewater treatment plant (WTTP). In order to maintain a sanitary environment in Sendai during the construction of the new WTTP, a temporary municipal wastewater treatment was required to meet the effluent standard BOD of 60 mg/l as proposed by the National Sewerage Disaster Countermeasures Committee of the Ministry of Land, Infrastructure, Transport and Tourism. Therefore, the government implemented a mid-level treatment employing a contact oxidation with string media. MGWTTP became the largest WTTP that adopted this method in Japan. Operating the mid-level treatment facility, the new MGWTTP was completed five years after the Great East Japan Earthquake. In this paper, the process until the completion of the new MGWTTP is outlined. The Sendai Declaration of Sewerage Works Disaster Risk Reduction, which was adopted at the 2015 Sendai Symposium, is also introduced.

During the 2011 Off the Pacific Coast of Tohoku Earthquake, a great number of earth structures suffered widespread damage. It took a significantly long time to repair, restore, or reconstruct many of them, and thus the relief operation activities and the rehabilitation works to be conducted at the sites and in the nearby areas were severely obstructed owing to the loss of their function. In this paper, a severe collapse case history of earth-fill dams for an irrigation reservoir is described as a typical and representative case. Based on the lessons learned, a proposal is made for the revision of their design policy, particularly in terms of soil compaction control and issues related to seismic design and construction of earth structures to satisfy the required seismic performance. Its application to the restoration works of the collapsed earth-fill dams is also preliminary reported. It is shown that the old dams collapsed due mainly to their generally poor compacted state and because their top fill consisted of particularly poor compacted sandy soil. The relevant and realistic design should be based on the following procedures: a) use of Level 2 design seismic load relevant to a given earth structure; b) use of realistic soil shear strength, corresponding to the average of actual values of the degree of compaction, which is noticeably higher than the given allowable lower bound; and c) evaluation of the stability by comparing the calculated residual displacement/deformation of a given earth structure with the allowable limit specified in the design. The results of the compaction control at the early stage of the restoration work for the new dams show that the newly proposed method that controls the water content of the backfill to be compacted and the dry density and the degree of saturation of compacted soil works very well.