Takatoshi Noguchi

Use of Cement-Treated Lightweight Soils Made from Dredged Clay

Recently, a new runway designated “D-runway” was constructed at Tokyo Haneda Airport. In this project, a large amount of cement treated lightweight soils made from very soft and mildly contaminated dredged clay was used. In this paper, a seawall structure using a cement treated lightweight soil made from dredged clay is introduced and the quality control of these soils in the construction work is discussed. Two types of lightweight soils, “pneumatic mixing cement treated soil” and “air-foam treated lightweight soil,” were used as backfill in the seawall structures. Design and quality control of the lightweight soils were carried out, and the seawall structures were successfully constructed. The shear strength and bulk density of the lightweight soils placed in the sites met the required specifications in design.

Evaluation of airport runway pavement based on pilots' subjective judgement

The fourth runway at Tokyo Haneda International Airport is to be constructed in part on a pier structure where it extends across a river mouth. Factors expected to affect aircraft operation safety and riding comfort are the deflection of the pier deck and the faulting between the pier structure and the adjoining reclaimed land. The objective of this study is to investigate these effects using a subjective evaluation method and, on the basis of the results, to select a suitable pier structure. Flight simulators representing the operation of a Boeing 747 and a DC 9-81 are used for this purpose. Runway profiles are created to represent different magnitudes of deflection and faulting, and these are input into the simulation program. Responses obtained from participants (experienced pilots) in the form of a questionnaire are recorded on a four-point scale. Analysis indicates that the operation safety and riding comfort decrease with the increase in deflection or faulting. Riding quality ratings are poorer than those for operation safety. Based on the criterion that at least 50% of the pilots rated the riding quality of a runway surface as uncomfortable or worse, an appropriate pier structure and the critical value of faulting are recommended.

Experimental validation of hydroelastic analysis of pontoon-, semisubmersible-and hybrid-type VLFS

This paper presents a hydroelastic analysis of pontoon-, semisubmersible-, and hybrid-type VLFS and its experimental validation. In the analysis, the detailed configuration of the experimental model is considered by using three dimensional finite element (FE) method. Experimental models measuring 15m in length, 3m in width and 0.03–0.23m in draft (depending on whether it is the pontoon and semisubmersible part) are built. The experiment has been made in the wave-basin with the bottom-slope of 1/75. At the same time, a hydroelastic analysis is carried out using the same models as the experimental ones in a wave-basin with flat as well as slanting bottom with slope of 1/75. By comparing the numerical results and experiment, the effect of bottom slope is verified. In the analysis of the semisubmersible part, the effect of viscous damping is considered by using the drag force formula with assumed drag force coefficient of 2.0. A comparison between the experiment and the analytical results indicates that numerical results from the semisubmersible part with additional effects of viscous damping agree better with the experimental results than those without. An experiment using irregular waves is also carried out and compared with the numerical predictions. Finally, the steady drift forces are analyzed using the far-field method and compared with the experiment.Copyright

Hydroelastic analysis of a hybrid-type VLFS in water of variable depth

This paper presents a hydroelastic analysis of a hybrid-type VLFS in variable sea depth. The VLFS model is the prototype of a floating runway with dimension 3120m in length, 524m in width, 1.5m in draft for pontoon part and 11.5m in draft for semisubmersible part. A three dimensional Finite Element model using beams and quadrilateral plate elements are used in the hydroelastic analysis in order to obtain an accurate approximation. An equivalent plate model having the same eigenfrequencies and eigenmodes in air is also used in the analysis. The results using the 3D model and the plate model have been compared and their agreement is satisfying. In order to examine the variable sea depth at the expected site, the hydroelastic analysis is carried out for a flat bottom, a constant slope, and a variable sea depth case. The effect of variable sea depth is found to be significant.© 2008 ASME

SLIT-TYPE WAVE ABSORBING STRUCTURE APPLIED ON STEEL PIPE SHEET-PILE CELLULAR SEAWALL

In the Tokyo International Airport (Haneda Airport) expansion project, the 13 runway will be constructed as a hybrid type structure with the piled-elevated platform and the reclaimed island. in the connecting area of the both part, a wave absorbing structure is planed to construct on the steel pipe sheet-pile cellular seawall to avoid the oecurrence of uplift pressure under the platform and the high reflection waves. The hydraulic model tests for the slit-type wave absorbing structures have been performed to measure the wave reflection ratio and wave pressure distribution on the structure. This experiment showed the most suitable settings of the wave absorbing structure for the project.

LABORATORY VERIFICATION ON PERFORMANCE OF PIER DECK PAVEMENTS AT RUNWAY D IN TOKYO INTERNATIONAL AIRPORT

As the fourth runway at Tokyo International Airport (Runway D), the hybrid structures consisting of asphalt pavements on the pier are planned in part. As their behaviors against aircraft loading have been scarcely studied, several aspects on asphalt pavements on the pier (concrete decks) are studied through a variety of laboratory tests. The following results were obtained. 1) The surface course asphalt mixture with type H polymer-modified asphalt has the sufficient durability against both the repeated loading and the segregation between asphalt and aggregates. 2) The bonding between asphalt mixture layer and concrete deck is secured after 20, 000 times of repeated wheel track loading. This is also true in the case of loading test under the submerged conditions. 3) Three kinds of asphalt mixtures composing the surface course on concrete deck have the sufficient fatigue resistance as they have never been failed in 200, 000 times of loadings.