The Committee of Safety Problems under the Japan Society of Civil Engineers is conducted by 5 subcommittees. The objective of the Subcommittee of Safety Education that is one of 5 subcommittees is to survey and to protect the accidents in the construction site. For this purpose, this subcommittee gathered information on safety education in practical construction sites through a questionnaire.
  In this paper, the statistical results of three questions for the safety education in the practical site were shown, and the realities of safety education that have been actually practiced in the construction site were described. These statistical results made it clear that the hazard prediction activities (KYT) were particularly effective in the construction site. For engineers' reference, the hazard prediction activities in the various fields were surveyed, and the present conditions and some problems in these activities were described. These investigations made clear that it is important to revice and share the teaching materials for continuing effectively the KYT.

View full abstract

  Astudy is made on the State Tort Liability Law article 2 and safety of infrastructures. The State Tort Liability Law is enforced in case of infrastructure accidents. The article states “The national government or local governments are liable to compensate for any damages to others due to flaw in construction and management of infrastructures such as roads and river etc.”. In this study, cases are studied to find out concept of infrastructures safety meant by this law. It is found that safety concept applied to road safety and river dike safety are quite different. Some suggestions are made based on these observations.

View full abstract

  We conducted a comprehensive study on the social impact of the I-35W bridge collapse through published documents by governmental and media organizations in the US. We find that the bridge collapse has not only caused direct loss including substantial loss of life, loss of road-user costs and Minnesota's economy due to the unavailability of the river crossing, but made far-reaching impact on the nation. First the collapse has raised national concerns about bridge safety. Diverse measures including special nationwide bridge inspections, publicity activities on the safety of bridges, rehabilitation or replacement of bridges more than before, a proposal for strengthening bridge inspection standards and processes have been taken to mitigate the concerns. Some specialists said that some of the measures have little improvement of bridge safety judging from some rationally-based criteria. The magnitude of the cost of these measures intended for the 600,000 bridges nationwide appears to be grater than that of direct loss derived from the specific one bridge, the I-35W Bridge.

View full abstract

  The concrete linings constructed by NATM oftenly have cracks at the tunnel crown in the longitudinal direction. This crack pattern looks similar to the cracks caused by earth pressure, this causes the difficulties to evaluate the soundness of tunnels, and to perform the maintenance and repairing. In this study, we carried out the model tests and the numerical analyses in order to simulate the conditions of construction and environment to clarify the mechanism of cracks generation. The results show that; for a concrete lining that has no displacement constraints between the surface of a concrete lining and a shotcrete, the difference of drying shrinkage between the surface and the inside of a concrete lining, is the main factor that causes cracks at tunnel crown. We also found that in order to simulate the mechanism of cracks generation correctly, not only the coupled stress-thermal analysis but also the coupled stress-moisture analysis should be performed in numerical analysis procedures.

View full abstract

  This paper provides a review of Federal and States legislation, technical manuals, and National Transportation Safety Board (NTSB) reports on quality control of highway bridge design. Included are interviews with some officials from the Federal Highway Administration (FHWA) and State Departments of Transportation (DOT). We observe that there are some common design quality control practices used across the nation while States DOTs use mixed practices. Legislation requires State DOTs to review Consultants' design as an owner and maintainer of a bridge while Consultants are required to bear the liability for design. State DOTs set out their design quality control procedures in their manuals, employ experienced bridge engineers to review the Consultants' design, and require Consultants to perform thorough checks of the design. Some State DOTs require Consultants to perform independent calculations that are conducted by the checkers. Some State DOTs implement some measures such as confirming that checks have been done by the Consultant, paying adequate compensation for checks to encourage Consultants to carry out thorough checks.

View full abstract

  Securing an airport function during and after a great earthquake is very important from the viewpoints of emergency medical service and special operation for transporting relief supplies to disaster areas. However, it is difficult to estimate the damage to airport facilities by a great earthquake. In this study, full-scale field experiment using controlled blast technique was carried out to assess the performance of airport facilities constructed in waterfront soft ground subjected to the liquefaction. This paper describes the effectiveness of countermeasure for liquefaction to the runway pavement based on the observational results of the liquefaction behavior of runway pavement and the damage analysis of the runway pavement on the improved and the unimproved ground.

View full abstract

  Because road sweeping cannot be carried out during winter in cold region, road dust in early spring increase. Although all roads managed by Sapporo city are divided into six ranks and their road sweeping frequencies in early spring are provided more than theses in regular season, the effect of road sweeping has not verified yet. In this study, we found that the accumulation process and grading of road dust in both seasons. The aesthetic beauty of roads with various amount of road dust was scored by public and the optimal road sweeping frequencies necessary for aesthetic beauty were obtained. Moreover, we discussed the validity and improvement of present road sweeping frequencies in Sapporo city.

View full abstract

  This paper is reviewed of the heat exhaust effectiveness during fire by installing chimney in the road tunnel, an experiment is carried out on a 1/5 scaled model tunnel, and report on this results to evaluate the numerical simulation. The model tunnel geometry and experimental conditions were set by considering Froude Number and Reynolds Number which are similarities of fire phenomenon. The amount of the heat flux that is vented from the chimney exhaust, it has shown that in the thermal fume average temperature increase in front of the vent is proportional to the 3/2 power. Results were same tendency even though it became thermal fume temperature rise. It is also shown that the heat exhaust efficiency is within a range of 0.44 to 0.61 and almost completely independent from the inside the thermal fume in front of the chimney. Furthermore, a universal validity of results of the model tunnel experiment, that LES simulator "Fireles" verified effect of the tunnel length of downward of chimney, the stream place of around chimney is almost the same, and exhaust heat flux proportional to the 3/2 power of thermal fume temperature rise have been valid similarly.

View full abstract

  The authors performed numerical analyses by rigid-plastic finite element method to clear a reinforcing mechanism and settlement reduction effect of side piles. As a result, the authors found that the reinforcing mechanism of the side piles is to keep the slip line away from the tunnel and prevent a concentration of a failure area. The authors also found that the side piles need to have the enough length to cross the slip line and the side piles become effective when the side piles are fixed to the tunnel tightly, the ground has large internal friction angle, and the side piles is installed at lower part of the tunnel.

View full abstract

  The patching repair method for concrete structures is a method comprising the removal of deteriorated and damaged concrete as well as deteriorative factors from outside and the restoration of the original shape with a patching material. However, little information on the durability performance of such materials is available, though their packages bear their basic physical properties and workability. The authors then thought that it was necessary to decide the performance of a patching material to be used from the deterioration situation of the structure and concrete quality to secure the durability of the structure after repair. In this study, a method of evaluating the performance of patching materials was investigated to make efficient and economical selection of a material. This paper also proposes a method of estimating the durability performance of an actually applied patching material based on evaluation under basic test conditions and evaluation by the changes and scatter of its performance in the process of producing, placing, and curing.

View full abstract

  This paper describes an improved particle swarm optimization (IPSO) which is one of the practical optimization methods for metaheuristics strategies. The proposed method is able to improve the search efficiency of the optimal solution by a synergistic effect of the two functions, that is an efficient narrowing-down function for solution space and a slowdown function in the particles. This paper also describes the results of applying the method to an actual deteriorating concrete sewer pipe by bacterial corrosion. It will be able to become a practical prediction tool for corrosion depth in sewer pipes and also to help to establish the rational maintenance strategies for sewer pipe networks.

View full abstract

  The sediment-related disaster warning system has been operated since 2005. But there were some cases that the residents did not take a refuge because the critical line hazard information did not reach them.
  In this study, the method to convert RBFN value into probability of disaster occurrence using a logistic regression model is investigated. As a result, RBFN value becomes an index which can be understood directly and easily so that this value can be utilized for the judgment of emission of evacuation warnings or sediment-related disaster warnings.

View full abstract

  A hydrogen gas is expected to be a clean, environmentally-friendly future energy source. In order to supply a hydrogen gas with a fuel cell station, the employment of buried pipeline is being studied in Japan and foreign countries. To implement this idea, the most important thing is to ensure the safety against the hydrogen gas leakage from the buried pipeline. Specifically, the understanding of a hydrogen gas movement charactersitics within the compacted soil is extremely important as well as the reliability assessment of pipeline materials. Aiming to establish a safety basis for buried hydrogen gas pipeline system, the full-scale experiment on underground hydrogen gas leakage and the numerical simulation were carried out. The movement characteristics of a hydrogen gas within the soil was investigated and the leaked hydrogen gas was detected at the road surface by the portable gas detector, following the procedure specified by the legal requirement.

View full abstract

  In this paper, the methodology associated with planning for maintenance of ground anchors based on inspection results is presented. In detail, the performance deterioration process of ground anchors is modeled by using Markov chain process. First, this study points out that the proposed method is very useful through simulation of in-situ inspection results. Secondly, the results of prediction on performance deterioration process of ground anchors provides the priority of locations to be inpected. Thirdly, the method modeling repair/renforcement strategy is proposed. Finally, the results points out that the methodology associated with planning for maintenance of ground anchors is very pratically effective.

View full abstract

  This paper presents the analytical method suitable for modeling hydraulic plastic grout injected as a void filling material. The analytical method, including fluid equations, a grout boundary expression and time-dependent rheological property's change, showed good correlation with such theoretical values as stress in stable condition and velocities in one dimensional uniform flow. The method was then adopted to a field experiment in which hydraulic plastic grout was injected continuously into a rigid box equipped with pressure gauges. Analytical results could simulate the observed behavior well and consideration of time-dependent rheological property's change was found important for the quantitative estimation for grout pressures.

View full abstract

  Japan Atomic Energy Agency has been excavating deep shafts through sedimentary soft rocks in Horonobe, Hokkaido. From the viewpoint of the observational construction, site engineers need a practical guide to evaluate the field measurements conducted with shaft sinking. The author analyzed the relationship among initial deformation rate, observed deformation, the ratio of the modulus of elasticity of rock mass to the initial stress, and the magnitude of inelastic behavior of rock based on convergence mearsurements and investigation of rock mass properties on shaft walls. As a result, the rock mass behavior classification for shaft sinking which consists of three classes was proposed.

View full abstract

  Road administrators are pressed with responsive maintenance works day after day, though they emphasize the importance of planned maintenance in road structure maintenance management. In this paper, with the recognition that responsive maintenance is important as well as planned maintenance, significance and improvement of responsive maintenance is discussed. Responsive maintenance works are considered to be opportunities of raising road users' satisfaction as beneficiaries and tax payers, and of improving relationships of mutual trust between citizen and the road administration. Proposed is an improvement framework with objectives of cost reduction, reduction of working time and shortening of waiting time.

View full abstract

  The research has been made a prototype of Remote Collaborative Visual Inspection System by linking digital movie, captured by a running vehicle, and online road drawings.The system revealed that our approach for digitizing road infrastructure data using a commercial HDV camcorder and scanned drawings is effective for road management personnel. However our system enables users to examine road condition on their desks, most of the decision-makings are depend on the personal experience and knowledge. The needs for some quantitative and data-driven indices that describe road condition without any ambiguity would be our next challenge to work on.

View full abstract