This paper examines the ‘hub-ness’ of Asian major cities in terms of international air traffic flows and analyzes the effects of new airports on the hub-ness of cities. After evaluating the international air network structures in Asia for 1982, 1990 and 2000, the degrees of hub-ness for prospective seven major cities in Asia from 1982 to 2000 are clarified by a basic gravity model composed of GDP, population and distance introducing ‘city-dummy variables’. The effects of Kansai International Airport (KIX) on the hub-ness of Osaka are also examined by panel data analysis introducing ‘new airport-dummy variable’. The results reveal that Tokyo, Hong Kong and Singapore are strengthening their positions as international air transportation hubs in this region. From the temporal analysis, the hub-ness of Hong Kong and Seoul is remarkably on the rise. On top of these cities, Osaka is having larger and larger hub-ness in virtue of KIX.

View full abstract

Today, Japanese air transportation market has the following major issue. Levels of service were set low for most routes to airports located in underpopulated regional areas. Since the potential demand has not surfaced on such routes, airlines have lowered the provided levels further, consequently getting caught in a vicious circle. To improve this situation, the government's public assistance to airlines is considered effective. The purpose of this study is to verify effects of public assistance for regional air service. Specifically, two points were examined: 1) analysis of the role of public subsidies in the formation of a regional air network, 2) quantitative analysis of the economic ripple effect on Hokkaido by the operation of HAC. In conclusion, the following two findings were obtained: 1) the subsidies contributed to early expansion of the regional air network, 2) the economic ripple effect reached approximately ¥1.15 billion for five years after starting operation.

View full abstract

This paper addresses the methodology of reduction of air traffic delay based on integer programming problem. It is assumed that each hub is used as the primary hub airport for the independent. In this paper, we propose the bi-level structure for optimizing the delay recovery: the upper level is the Aviation Operation Center (AOC), which is controlling the hub-to-hub schedule: the lower level is controlled by the Local Hub Operators (LHO), which handle both hub-to-hub and hub-to-spokes schedules. Finally, numerical examples are carried out to show how the proposed method works.

View full abstract

The purpose of this paper is to present a Fuzzy Quality Function Deployment (FQFD) model to achieve service quality assurance prior to the implementation of service action. This paper examines the difference requirements among airlines, airfreight forwarders, and airport warehouses in Taiwan airport cargo terminal users. Then, combining experts' opinions, service management requirements are developed for satisfying the observed difference customer needs. Although efficient cargo terminal operations are critical for improved performance of users, few studies have focused on cargo terminal performance. Therefore, a fuzzy relation matrix for linking service management requirements to customer needs is constructed based on cross-functional expertise. The aggregated fuzzy assessments of different service management requirements are also ranked to prioritize and determine their importance. The methodology presented here can be generalized to other airport cargo terminal and to improve their ground handling efficiency and to enhance their overall revenue.

View full abstract

The increasing demand on air traffic has resulted in a growing concern in ground access to the Hong Kong International Airport by the Airport Authority Hong Kong together with various types of transport operators. In this study, the ground access mode choices to the airport are examined with the objectives of categorising the service performance both expected and received by passengers. Focus is on air passengers departing Hong Kong, exclude arriving and transfer/transit passengers. In an attempt to understand their access mode choices, interview surveys have been conducted. A structural equation model has been calibrated to determine how various personal and trip characteristics affect departing air passengers' modal choices. Latent variables regarding departing air passengers' expectation and perception on selected service attributes of the modal choices are considered in the analysis. The gap between passengers' service expectations and the actual service perceived to be happening were examined, while importance-performance analysis was used to construct evaluation maps to identify those service attributes necessitating improvement. The results provide source information for various types of transport operators in their quest to improve their individual services and increase their share of the airport ground access market.

View full abstract

The model explained here explores influence of the type of queue and operator service time on the check-in process at airports. The proposed model is based on queuing theory concepts and attempts to compute the optimum number of check-in counters. A time block concept related to counting periods is adopted. A graphical output indicates delays and passenger waiting times over the period of analysis. The congestion levels can be analyzed under given number of service counters in operation. This analysis method is then able to compute the optimum number and the configuration of check-in counters. The optimization is based on cost minimization. Comparison with real operations in five international airports is included.

View full abstract

This study formulates a dynamic programming model to determine the optimal facility purchase and replacement scheduling by considering facility renewal costs, aviation safety, passenger service level, and airport finance. The study constructs various cost functions on facility depreciation, operation, maintenance and delay for different facilities at different time stages according to passenger volume, facility reliability and utilization so as to reflect dynamic variations in those costs. Moreover, this study uses CKS international airport as an example to demonstrate the application of the model. The results indicate when the malfunction rate is higher than a certain level, such that the total maintenance and delay costs are higher than the total capital, depreciation and abandon costs to renew the facility, then the replacement must be done. This study provides the airport authority optimal strategic decisions on the purchase and replacement of various facilities in terms of quantities and timing.

View full abstract

On November 18, 1987, the Ministry of Transportation and Communications, Taiwan, announced an ordinance allowing new airlines to be established and routes developed. Taiwan's air industry thus saw a lot of change. This paper explores the outcomes of airline competition and survivability resulting from the liberalization policy through a research on the relative efficiencies of Taiwan's domestic airlines. The result shows that all of the new-entrant airlines had difficulty in using their inputs efficiently in their initial stage of operations. However, their scale efficiencies improved year after year. The incumbent airlines' efficiencies were also improved. This implies that competition between the carriers resulting from entry relaxation was indeed intensified and thus performances were improved. In addition, because of the un-removable barriers of competition, most new entrant airlines indeed experienced the life cycle challenge: growth, decline, and collapse. All the newcomers except UNI Air, a subsidiary of EVA Airways, disappeared.

View full abstract

Perishable asset yield management has wide applications in airlines seat inventory control, rental car and hotel room reservations. In contrast to the research on optimal dynamic pricing that has taken place in the past decade, we examine the practical merit of a constant price policy. This means a single price is applied to an item throughout the sales cycle.. We present procedures to identify the optimal constant price for two different applications. In the first, there is full dilution and in the second there is no dilution (dilution is when a customer that is willing to pay a high price is satisfied at a low price). We also propose a more flexible constant price policy (hybrid method) in which prices can be changed at discrete intervals and we present a method for its optimal policy. Furthermore, this hybrid method is capable of incorporating the costs associated with price change explicitly.

View full abstract

The main purpose of this study is to present an evaluation method that employs the well-established Importance-Performance Analysis (IPA) for understanding airline passengers' degree of care, degree of satisfaction and priority list on some critical service items. The analysis results will serve as the basis for airlines to improve their service strategies in response to customer needs. The proposed method has been applied in the Taiwan UNI AIR market analysis through a comprehensive passenger survey. The application results clearly indicate that the proposed IPA method can effectively identify critical airline service items to be improved, and serve as a valuable tool to assist airline managers in developing airline service improvement strategies.

View full abstract

This study developed an instrument, based on the SERVQUAL model, to gauge the characteristics of specific cross-strait routes, in order to measure the service quality, perceived by travelers from Taiwan and Mainland China, of cross-strait airlines. Further, we analyzed the differences in the perceived service quality provided by Taiwan cross-strait airlines and explored the relationships between service quality difference and passenger satisfaction and preference behaviors, using a path analysis model. The results indicated that there were significant differences between the perceptions of Taiwanese and Mainland Chinese travelers related to cross-strait airlines, in all service attributes. This implies that even though the peoples of Taiwan and Mainland China share the same culture and speak Mandarin, their perceptions of airline service quality can be quite different. Finally, the path analysis model results showed that not all services significantly affected passenger satisfaction. It was also found that some services affected passenger preferences towards certain airlines.

View full abstract

This study primarily focuses on 1) shipper's route choice preference among various short-sea container routes, 2) historical trends of cargo movement and resulting patterns of the short-sea container network structure, and 3) possible solutions to achieve a balance between demand scale and price strategy in the network, in the East Asian region. Firstly, trade-offs between transshipment and direct services are identified and measured through multinomial logit analysis using the latest container cargo flow data originating from and destined for Japan in 2003. Secondly, evolution in the structural change of emerging direct and pendulum routes (Japan-Korea-China) is summarized. Based on the above quantitative and qualitative analyses, the paper finally presents key policy implications for the future prospects. Findings of this study are expected to make practical policy contributions towards resolving weaknesses inherent in hub-network structure by realizing direct and pendulum routes for the regional short-sea container network.

View full abstract

The goal of this study is to propose a number of water transportation-related strategies which enhance the usage of the water transportation mode. In this study, Nonthaburi area, which is suburban of Bangkok, and Downtown Bangkok were selected as the study areas for the analysis. In contrast to the surface transportation, water transportation has a potential to provide a good service for passengers and goods movements. Particularly, in Bangkok there is a Chao Phraya river which runs through the center of city. It provides reliable, pollution-free, and scheduled transportation service. To obtain the model representing the trip characteristics and mode choice behavior, the Revealed Preference (RP) is employed. The Multinomial and Nested Logit Model were examined in order to explain the mode choice behaviors of travelers who travel between the study areas. The significant attributes in demand model were identified. Examples of significant attributes are in-vehicle travel time, out-of vehicle travel time, travel cost, number of car ownership, income level. The results showed that different trip purposes, work and non-work trips, had totally different mode choice behaviors. In the application stage, the developed model is employed to estimate the effects of policy decisions on travel behavior of overall patronage by changes in travel time and cost of water transportation mode. Several strategies that can improve the water transportation mode are discussed including service frequencies, information technology and multimodal transit center.

View full abstract

Employee benefits have grown in importance over the past several decades. A lot of past research has explored the issues related to effects of employee benefits. While most typically viewed benefits as hygiene factors and unrelated to productivity and unable to help firms gain competitive advantage, there was a consensus that benefits are valuable in attracting and retaining competent employees. This claim implies that benefits may have a moderating effect on the relationship between labor input and output. Given the limited statistical evidence, this paper sets out to examine the issue. Analytical models based on production function are developed, and several important control variables are considered. Based on two large samples from Taiwan's shipping industry, empirical examinations reveal that employee benefits have a moderating effect on firm productivity, irrespective of industry or firm size. Furthermore, the effect size is greater in small and medium enterprises (SMEs) than that in large firms.

View full abstract

Since “risk” is regarded as the core issue of fulfilling success in port partnership, we first define three types of partnering based on with/without resources involving, consider four risk factors and formulate two stages of risk processes, and then, develop a risk analysis model from the viewpoint of port operator (PO). This study acquires relative parameters through ways of questionnaires and in—depth interviews for Mote-Carlo simulation. It is concluded that the more market share a container carrier (CC) occupies the higher risk the PO involves in ‘resource-involving (RI)’ and ‘resources crossly-involving (RCI)’ partnerships; risk of PO also increases when partnering with multiple CC whose market proportion accumulate in ‘no resource-involving (NRI)’ partnership; on the contrary, the risk for PO decreases while cooperating with single CC in RCI partnership. The results will certainly be helpful for PO to evaluate the partnership risk with multiple CC and to develop marketing strategies.

View full abstract

The competitiveness of a port provides ship owners, operators and shippers with a significant basis in selecting a calling-port. Port operators can utilize the competitive advantage as a parameter for counter measures by grasping the advantages and disadvantages of the ports and be a prime factor of opportunities and threats of the ports. The determinants of port competitiveness are, however, subject to various sources, which do again depend on the elements of judged subjects, businesses, circumstances, the degree of knowledge or know-hows accumulated and the level of information exposure, and so on. Moreover, the components are mixed with quantitative and qualitative factors, and have a inter-active and complex relationship. Keeping this complicated nature of the business in mind, this paper will establish the fuzzy structuring method and apply it to the port industry so as to identify the subordinate and hierarchical relationships among the factors having an impact on port competitiveness and to draw a structural model that those involved in port logistics should consider.

View full abstract

The grey theory mainly works on systems analysis with poor, incomplete or uncertain messages. The popular grey model, GM(1,1) is efficient for long-term port throughput forecasting. However, it is imperfect when the throughput increases in the curve with S type or the increment of throughput is in the saturation stage. In this case, the throughput forecasting error of grey system model will become larger and the result is unaccepted in the real world. To solve this problem, we propose the grey Verhulst model on time series error corrected for the port throughput forecasting. By applying this Verhulst model to the port throughput forecasting, it shows that the grey Verhulst model on time series error corrected is applicable, especially, when the throughput increases according to the curve with S type, not only higher forecasting accuracy can be obtained, but also the superiority and the features of grey system model can be reserved.

View full abstract

In this research, we propose a partial equilibrium model that can measure the economic benefit of port development in Japan, and estimate the parameters of the demand and supply function concerning the long-distance container transportation market (i.e. North America Pacific Coast route, North America East Coast route and European route) which arrive at and depart from Japan. Then we evaluate the effectiveness of the investment for port development up to now with this model. As a result, we would conclude that port development in Japan has been effective in general. We also examine spatial incidence or distribution of economic benefits measured by the above-mentioned partial equilibrium model with simplified international Spatial Computable General Equilibrium (SCGE) model, including international induced effects. The results also show that port development in Japan can bring a certain degree of benefit to any regions in the world through the trades.

View full abstract

East Asia is the most blooming area among global container shipping services. Most of the oceangoing lines select major ports such as Busan, Shanghai, Yantian, Hongkong, etc. as the transshipment and hub points. Since the deployment of trunk routes operated by main liners in this region is getting complicated and diversified, it is worth while to comprehend the operations of shipping liner, and the influential factors of hub ports choice in this area. This paper starts with an overall analysis of the performance of hub ports and change of trunk routes deployment based on statistical data of port operations, slots supply and operating routes of main shipping lines etc., collected from various sources. Secondly, the influential factors of selecting hub ports by shipping lines are investigated by conducting a questionnaire survey. Finally, the Gray decision model would be used to rank the relative competitiveness of these major ports from the viewpoints of container liners.

View full abstract

While the regional economy integration has recently attracted much interest, its impact on the rapidly developing international marine transport industry is a major concern. This paper proposes a method for estimating the international container cargo OD flows under various hypothetical FTA memberships and transport technical progress by incorporating the GTAP model, which uses the applied general equilibrium theory to conduct the quantitative analyses of international trade issues. The effects under the FTA scenarios and transport technical progress scenarios on the selected countries' economy, social welfare, trade amounts and container OD flows are discussed. Since this method provides an approach for estimating the OD flows on a national wide level, it can be utilized for assessing the policy effects on international trade and transportation. Therefore, it is also an important step for demand forecasting such as the volume of container handling and transshipment on the international container shipping transport networks.

View full abstract

Ultra large ships have the advantage of scale economies, but whether they successfully getting into service depend on cargo flow, shipping distance, port efficiency and constraints, etc. The study constructs a two-objective model to determine the optimal ship size and sailings frequency and analyze the shipping economies of ultra large ships by minimizing shipping costs and inventory costs. The results show the Pareto optimal solutions of the two-objective model and optimal ship size and sailings frequency with respect to each level of inventory costs and shipping costs. The sensitivity analysis shows the optimal ship tends to be large as route flow increases. Furthermore, the economies and possibility of using ultra large ships tend to increase, as port efficiency improves, shipping distance increases, the ports of call decreases, or the relative costs of large ships decrease.

View full abstract

In this paper, we establish criterions for classifying marine accidents to integrate the navigation safety system of Taiwan. Together with unpredictable of marine accidents, the inaccuracy of maritime data in Taiwan makes marine incident information possess the characteristic of Gray message as described by Gray Theory. After analyzing the data of 107 marine incidents, we classified the accidents into four types by the Gray Clustering Method. The results revealed that the crew's negligence accounts for 93.5% for the cause of all accidents. Furthermore, 85.1% of crew's negligence is caused by senior crew. Through classifying marine accidents, this paper not only makes the port managers of port bureaus and insurance companies realize the damage levels of various kinds of marine accidents and their causes, but also provides the managers of harbor bureaus a basis to strengthen seamen's quality and management.

View full abstract

Porous wearing courses improve traffic safety and can potentially reduce traffic noise. However, its service life is shorter compared to dense mix due to clogging and poor durability. This paper presents the characterization of the clogging behaviour of single and double layer porous asphalt (PA) mixtures. The double layer PA comprises of a finer upper layer and a coarser bottom layer and was historically developed to further reduce traffic noise. Two gradations comprising of 10 and 14 mm top layer maximum aggregate sizes were compacted to 30, 20 and 15 mm thickness, while the maximum aggregate size for the base layer is consistently maintained at 20 mm. The clogging behaviour of the double layer was compared to the single layer PA specimens. The laboratory experimental results showed that the double layer PA made with SBS exhibit drainage time 37% less upon cleansing as compared to similar single layer 10 mm maximum aggregate size porous asphalt.

View full abstract

In this paper we propose a mathematical model and its algorithm to build the optimum road sign system that keeps drivers on their original course. We assumed that signs were posted only at the entrance of intersections. Furthermore we defined the Straying Index as an expression of drivers straying and proposed a method for minimizing the total Straying Index of all OD. In this method, the total Straying Index of drivers was taken as the objective function, while the number of links where signs were to be posted and the numbers of displays for one direction on the signboard were treated as the restrictions. We solved this problem through the analysis of a small network example using dynamic programming and extracted some properties of sign type by taking into account such characteristics as place name, route number, and the combinations of both.

View full abstract

Reinforcement consists of incorporating certain materials with some desired properties within other material which lack those properties. The concept of using fibres to improve the behaviour of materials is not new. The modern developments of fibre reinforcement started in the early 1960s. A multitude of fibers and fiber materials were introduced and are continuously being introduced in the market.
Stone Mastic Asphalt pavement surfaces have been used successfully in Germany on heavily trafficked roads. In recognition of its excellent performance a national standard was set in Germany in 1984. Since then SMA has spread and gained acceptance all over the world, because of its excellent performance characteristic the use of SMA increased in popularity amongst road authorities and asphalt industry.
This paper presents the characteristics and properties of glass fiber reinforced Stone Mastic Asphalt, which may have the benefit of improving the performance of road pavement. To evaluate the effect of the fiber content on the bituminous mixes, laboratory investigations were conducted on the samples with and without fibers. The testing undertaken in this research comprise the marshall test, indirect tensile test, creep test and resistance to fatigue cracking by using repeated load indirect tensile test.
The use of Glass fiber showed consistent results and it was found the addition of fiber does affect the properties of bituminous mixes, by decreasing its stability and an increase in the flow value as well the voids in the mix. The results indicated that the fiber has the potential to resist structural distress that occur in road pavement as result of increased traffic loading, thus improving fatigue life by increasing the resistance to cracking and permanent deformation. On the whole, the results showed that the addition of glass fiber will be beneficial in improving some of the main properties of the flexible pavement.

View full abstract

In Japan, the evaluation procedure for infrastructure investment projects have been developed well in past ten years, while the evaluations of regulatory provisions are yet to be implemented in spite of OECD recommendation for applying cost benefit analysis (CBA) to regulations. One of the candidate regulations for applying CBA is speed limit regulation since speed limit is set by police agencies without any objective analysis, and the ongoing reform process in road sector is considering relaxation of speed limit in general trunk roads as an alternative policy option. This paper proposes an analytical framework based on CBA and make an attempt to apply the framework to objectively evaluate the resulting costs and benefits due to relaxation of regulated speed in one expressway route in Japan. The result of analysis demonstrates that a net positive benefit can be achieved by upgrading regulated speed.

View full abstract

Highway improvement and maintenance have supplied the economic development and enhanced our life convenience greatly. However the economic and social conditions changed heavily in Japan. The long period economic inactivation, the low birthrate and longevity constrain the investment to public projects strictly. The public works meet the criticism for the estimation of the effect and the mismatching between the projects and the local needs with any new highway improvement project contemporaneously. In this study, I applied VE (Value Engineering) as an evaluation approach for the highway improvement plans. The work started with the function definition and finished with the proposal of design principles on improvement plan. Finally, the study verified the effect of VE as a valid approach for the evaluation of highway improvement plans to help us to choose the best plan fitting with all of conditions and limitations.

View full abstract

Cost estimation of highway projects with high accuracy at the conceptual phase of project development is crucial for planning and feasibility studies. However, a number of difficulties arise when conducting cost estimation during the conceptual phase. Major problems faced are lack of preliminary information, lack of database of road works costs, data missingness, lack of an appropriate cost estimation methods, and the involvement of uncertainties. Given its significance, conventional tools such as regression analysis have been widely employed to tackle the problem. However, recent statistical studies show that errors in cost estimation have not decreased. This paper focuses on the development of a more accurate estimation technique for highway projects in developing countries at the conceptual phase using artificial neural networks.

View full abstract

The purpose of this study is to evaluate the actual highway geometric design properly, and propose a well-balanced design policy especially considering the drivers perception and behavior. In this paper, after classification of all the design elements, the new concept of ‘reversely calculated speed’ as an evaluator of road alignment is introduced and examined. The analysis of the ‘reversely calculated speed’ for actual alignments on Expressways in Japan shows the drivers' perception of physical limitation given by road alignment. Then the actual operating vehicle speed is estimated and analyzed using database of vehicle detectors. Using the five-minutes mean speed, with only one passenger car, observed by detectors in the median lane on more than 7,000 km networks of Expressways in Japan, the speed running absolutely independent can be assumed as an ‘operating speed’ (free speed) reasonably. At last, the values of operating speed are evaluated with highway design elements such as curvature of horizontal radius and vertical grade.

View full abstract

The objectives of this paper are to evaluate aggregate characteristics including elongation, flatness, and other shape indices. The following particle shapes were selected for this study: cubical, rod, disk, and blade. The change in rotation angle of coarse aggregate was found to correlate well with the internal resistance of a HMA mix. The particle index (PI) was shown to be an adequate measure of the combined contribution of particle shape, angularity, and surface texture to the stability of an aggregate. The PI value correlated well to aggregate geometric characteristics including elongation ratio, flatness ratio, shape factor, and sphericity. Cubical particles were desirable for increased aggregate internal friction and improved rutting resistance. The more cubical the aggregate, the higher the PI value. The PI value of coarse aggregate significantly affected the engineering properties of a HMA mix. The particle shape determined how aggregate was packed into a dense configuration and also determined the internal resistance of a mix. Of the four particle shapes evaluated, the cubical aggregate demonstrated the best rutting resistance. Flaky and/or elongated aggregate was shown to have lower compactibility and higher breakage.

View full abstract

Starting in the early 1960's, studded tires had been popular with motorists in the cold and snowy region Hokkaido, Japan. However, after about 20 years dust pollution caused by these studded tires became a serious environmental problem. Then, throughout various public “Non-Studded-Tire” movements, the Studded Tire Regulation law of 1990 was enacted to prohibit the use of them in order to eliminate dust pollution. The regulation has positively eliminated dust pollution; on the other hand, however it has brought about the negative effects with the regulation's unexpected result of making winter roadways extremely slippery. Those include increased winter accidents, worsened winter traffic pattern, and increased deicing chemical usage, and these remain unsolved. The following study evaluates the studded tire regulation enacted in 1990 by employing the logic model approach with the intention of contributing how to evaluate road maintenance programs.

View full abstract

During night times, drivers are highly dependent on road marking retroreflectivity for delineation. Technically speaking, retroreflectivity, which equals to luminance, means the amount of light ray that entered glass beads and reflected to drivers. It has been recommended that the retroreflectivity is evaluated, monitored and controlled at implementation stage or during maintenance. For this reason, the minimum retroreflectivity is postulated based on regulations such as “Polices' Manual on Traffic Safety” and “Manual on Roads” in Korea. This study focuses on the drivers' responses for the minimum retroreflectivity. Subjective evaluations by 49 subjects and quantitative measurements of pavement marking samples especially manufactured with various ranges of retroreflecivity were made in KHC Test Road. The effects of color and material retroreflectivity range were considered. After completion of the experiment, the minimum in-service level, 130∼140 mcd/m²/lux for white markings and 100∼110 mcd/m²/lux for yellow markings, from a driver's point of view was established.

View full abstract

This paper presents the evaluation of work zone capacity in Thailand and the development of closure scheduling tools in order to schedule work zone by minimizing all related traffic impacts. The results of the capacity analysis revealed that the work zone capacities deriving in this study are higher than the work zone capacities suggested by the highway capacity manual, HCM 1994. These capacities are used to develop the closure scheduling tool. The developed tool is computer-based which considers the excessive flows due to lane closure and determine the dissipation period affecting from the closure. The results show the summary of dissipation durations for different closure schedules. To demonstrate the real world application of this developed tool, a selected section of Highway No.1 (Phaholyothin highway) was selected as a case study. Results revealed that the unsuitable closure periods are 6:00 hr. to 8:00 hr. and 16:00 hr. to 18:00 hr.

View full abstract

This study proposes the use of the Second-generation Wavelet Transform (SWT) for pavement preventive maintenance. New wavelet filters in the SWT are biorthogonal wavelet filters containing free parameters. This method is adopted to determine free parameters based on some training signals, which contain the localized road distress. Using free parameters, it is comparatively easier to determine an optimal basis function. Application of the filters to Training signals effectively leads to the detection of the characteristic points of the road surface. SWT was applied to the vertical acceleration of a vehicle on the road surface. When the form of the input data and the studied waveform of a free parameter were similar, a close-up of the output ingredient was taken. When form differed, it was not detected as a feature point. This is considered to be a very important factor when designing WT for use in pavement preventive maintenance.

View full abstract

The paper presents a systematic approach to find optimal maintenance strategies for pavement management systems by using the World Bank's Highway Development and Management System (HDM-4) combined with gradient methods proposed by Tsunokawa et al (2005). The optimal maintenance strategy is defined as the set of optimal maintenance options corresponding to different traffic levels and various initial pavement conditions, which minimizes the sum of agency costs and road user costs in present value or maximizes the net benefit to society over an analysis period. The basic data for the analysis was derived from the Vietnamese conditions and the most sensitive parameters in HDM-4 were calibrated into the local conditions for a basic application. The findings may help highway agencies in better applying the right maintenance work at the right time and thus result in savings with regard to the total transport costs to the society.

View full abstract

Mature infrastructures require proper maintenance treatments. Highway agencies often face with limited maintenance budget which may result a large backlogs of maintenance works in each year. The main objective of this research work is to develop a multi-objective optimization model to support the multi-year decision making process of the highway maintenance management in Thailand. Preventive maintenance is focused in this research since it helps prolong the life of the infrastructures. This study selects the flexible pavements in the Pathumthani province to be the study area. Both single- and multi-objective optimization models are developed for a multi-year maintenance planning by incorporating the constraint-based genetic algorithms to deal with the combinated characteristics of the network-level maintenance planning. Two constraints of budget limitation and the networksystem preservation are employed in the developed models. Maintenance scenario is selected to illustrate the utilization of the developed models.

View full abstract

SBS-modified asphalt is finding widespread application as a binder for high performance mixtures, and porous mixtures, etc. The performances of mixtures are greatly affected by the morphology of SBS. In this study, we made trial SBS-modified asphalt products of varying morphologies and clarified the relation of the dispersed conditions of SBS-modified asphalt to its performance and storage stability as the binder and mechanical properties of asphalt mixtures. As a result, we could show the morphology of SBS-modified asphalt required to ensure its proper performance.

View full abstract

In January 2002, a research experiment installed a number of sensors in taxiway N1 in the northern field of the Chiang-Kai-Shek (CKS) International Airport during a scheduled slab repair. The sensors measure changes of slab behavior in response to various environmental factors and different aircraft loading. The slabs are 6 m wide, 7 m long and with 41 cm in depth. A total of 102 monitoring devices were installed. These included the H-bar and the Dowel-bar strain gauges; position gauges, temperature gauges, and moisture gauges; as well as optical fiber sensors. This paper mainly focuses on the analysis of the instant data recorded by H-bar strain gauges generated by the taxing aircraft, including the variation of strain induced by aircraft of different gear configurations, the strain at different depths and the joint, as well as the comparison between the finite element method (FEM) analysis results and the field data.

View full abstract

In this paper, finite element program, MSC.NASTRAN was employed to analyze structural responses of three-dimensional simplified pavement models of low volume pastoral roads under the quiescent loads. Firstly, the models with three load positions have been put forward according to traffic investigation. Secondly, effects of the road shoulder materials, the curb and thickness of wearing course on structural response of the pavements were studied. Finally, the test roads were constructed and detected in Inner Mongolia prairie, and typical pavement structures for low volume pastoral roads were recommended.

View full abstract

The paper shows how to develop EALF of ten axles 80 tires trailer on flexible pavement structures, which is used to transport segmented concrete girder from fabricator site to project site. Total maximum weight is 175 tons. Trailer is operated between 10 pm - 4.30 am to minimize traffic obstruction. EALF analysis is based on mechanistic empirical method. As air temperature affects modulus of surface layer, Bandung's average minimum temperature is used. The result shows fatigue criterion determined its failure on pavement with high subgrade modulus, otherwise its failure criterion is based on permanent deformation. Thicker pavement has higher EALF when its failure is permanent deformation, otherwise EALF is lower. In general, EALF is within a range of 3.28 to 78.44. The higher the subgrade modulus, the lower trailer's EALF. Trailer's EALFs for subgrade modulus of 50 MPa is higher than subgrade moduli of 100 - 150 MPa. The difference is apparent with surface thickness of 150 - 200 mm.

View full abstract

Pursuing our previous research, the fatigue performance of Hot Rolled Asphalt (HRA) mix type C; referred to the British Standard Specification, and Superpave® Asphaltic Concrete (AC) mix; referred to the Asphalt Institute Specification, both using an ASBUTON (Indonesian Rock Asphalt) as fine aggregates and filler, were investigated. The parameters used to evaluate the fatigue characteristics of Asphalt Concrete mixes were: the number of cycles to failure or Fatigue Life, the Effectiveness Factor, the initial strain, the initial stiffness, the number of cycles for crack initiation, the number of cycles for crack propagation, and the cracking mechanism until failure achieved.
The results of the research showed that the use of Asbuton as fine aggregates and filler in HRA mix type C and Superpave® AC mixtures, could improve its Fatigue Life, indicated by an increasing of the Effectiveness Factor, i.e. the ratio of number of cycle to failure for specimens with and without Asbuton filler, at a given stress level, ranges from 15.71 to 4.90 for HRA mix and from 521.44 to 6.38 for AC mix, depend on its stress level.. The role of Asbuton filler in both asphalt mixture; HRA and AC appears also to decrease the Initial Strain, increase the Initial Stiffness (more than 300% for AC mix) and reduce the mechanism of crack initiation and crack propagation of the specimens.

View full abstract

Optical fiber sensors for measuring concrete joint movements were embedded in the concrete slabs during the reconstruction of primary taxiway at Chiang Kai-Shek International Airport since Jan. 2002. Field data have been collected regularly for the first 13 days of concrete curing, and continuously 48 hours per month on a monthly basis. Readings of the sensor 7 demonstrate the joint movements with seasonal temperature changes. It is found that the induced crack occurred four days after joint saw cut and the initial crack width is about 0.29 mm. Concrete slabs shrink during the curing time, mainly due to the drying shrinkage. Joint movement becomes more sensitive to air temperature around two weeks after curing. The slab moves toward joint when air temperature increases from January to June, and backward to its center line from September to January. The measured average moving rate is 0.035 mm per Celsius degree for a 7 m long slab. Due to the limited space at joint, slabs stayed at the closest condition for almost four months, from June to September, with the maximum horizontal compressive stress of 41 kg per square centimeter (586 psi). A prediction model of the readings of joint movement sensor is derived in this study, and the joint movements can be predicted by two regression equations with an average error percentage of 5.8%.

View full abstract

A stress-strain model called TESRA (Temporary Effects of Strain Rate and Acceleration), described in a non-linear three-component framework, has been developed to simulate the viscous effects on the stress-strain behaviour observed in an extensive series of drained plane strain compression (PSC) tests on clean sands. A similar model has been developed for the geosynthetic reinforcement also. The TESRA model was implemented into a generalized elasto-plastic isotropic strain-hardening nonlinear Finite Element code. The integration scheme to obtain the viscous and inviscid stress components according to the TESRA model in FEM analysis, which needs some specific considerations including the relevant choice of the suitable rate parameter, is described. The geosynthetic reinforcements were modelled by employing nonlinear elasto-plastic one-dimensional truss elements with three-component TESRA model. The axial force—axial strain—time relations of several types of geosynthetic reinforcements were successfully simulated by the present FE code called - “Geotechnical Nonlinear Analysis (GNA)”. The shear stress—shear (or axial) strain - time relations from two drained PSC tests on geosynthetic reinforced Toyoura sand were successfully simulated by the FE code embedded with the TESRA model. It is shown that the FE code can predict the time-dependent stress-strain behaviour of reinforced sand accurately without spending any significant extra computational time or storage.

View full abstract

The British pendulum tester is commonly used for the measurement of skid resistance of pavement surfaces. Although it is widely suggested that the measurement is largely governed by the microtexture of the pavement surface, experience has shown that the macrotexture can also affect the measurements. It can also lead to misleading results on coarse-textured test surfaces. This paper reports the findings of a study conducted to examine the effect of macrotexture on the British pendulum measurements. The study employed a three-dimensional finite element model to analyze the behavior of the test device. The results of the analysis showed significant variations of test results on sparsely spaced textured surfaces, especially those that exhibited discontinuities. The results demonstrated that the edge impacts between coarse-textured surface features and the pendulum slider would give rise to unreliable test measurements.

View full abstract

Single-slab models have been widely adopted the design and the analysis of concrete pavement. An implicit assumption of this approach is that the beneficial effects of joint load transfer are ignored. Field measurements and finite element analyses by researchers have shown that joint shear transfer had a significant influence on the state of stresses in the slab when the loads were applied near the joint. Hence, it is of practical significance to quantify the effect of joint load transfer on load-induced stresses in concrete pavement systems. The present study adopts a closed-form theoretical three-slab model to analyze the structural responses of concrete pavements under traffic loading. The analysis concludes that the effects of joint force transfer must be considered in the design and evaluation of concrete pavements in order to provide a structurally sound pavement structure for its intended design life.

View full abstract

The use of stabilized sub-bases for road pavements reduces or prevents the deterioration that is a consequence of poor material selection, difficult construction conditions and, in some cases, a low standard of construction quality control. Mitigation of these problems is important for both flexible and rigid pavements. This paper describes the early performance a full-scale flexible pavement trial that was built to evaluate the performance of alternative pavement and material designs using stabilized sub-bases and compare it with that of a traditional pavement design in use in the Philippines. The key variables in the research are the thickness of the stabilized layer which was varied continuously along each trial section and the strength of the sub-base layer which was varied in different sections. The trial pavement carries heavy traffic. Conclusions are drawn which suggest that the use of stabilized sub-bases significantly extends the life of the pavement.

View full abstract

Porous asphalt pavement is one solution to increased surface runoff due to urbanization by allowing temporary storm-water retention. This paper aims to establish a rational basis for material selection, drainage design and rutting resistance evaluation of a porous asphalt pavement of this purpose. Selection of suitable design porous asphalt mix and crushed stone base are made by studying the vertical drainage properties and the deterioration trends in permeability caused by clogging using the National University of Singapore (NUS) Falling Head Permeameter. Thickness design of the porous pavement, including the thickness of porous asphalt surface layer and that of the crushed stone base, is based on hydrologic and drainage analysis by means of finite element modeling. Rutting resistance of the pavement structure is evaluated through laboratory wheel tracking tests. Based on these three criteria, a recommended design of the porous asphalt pavement is proposed for car parks and roads in Singapore.

View full abstract

Flaky aggregates is normally avoided in bituminous mixtures, they influence the aggregate gradation, reduce interlocking characteristics, and it should be therefore limited. Indonesian National Standards (SNI) specified a tolerance of flaky aggregate content for a maximum of 25% in Asphalt Concrete mixture for surface course. Gradation was modified into 5 variations of flaky aggregate content, i.e. 5%, 15%, 25%, 35% and 45%. The Marshall test were done with 5 variations of asphalt content such as 5.0%, 5.5%, 6.0%, 6.5% and 7.0%, respectively. Each variation of flaky aggregate content resulted on different optimum asphalt content of 5.85%, 5.90%, 6.0%, 6.05% and 6.15%. Workability Index (WI) measured using gyropac (350 gyrations) at their optimum asphalt content show that the WI decreases with decreasing the flaky aggregate content. The results of Modulus measurement using UMATTA at their optimum asphalt content show that the modulus values decrease when the flaky aggregate content increase.

View full abstract

This paper looks into the development of a prototype Road Construction Material Selection System (RC-MSS) which based on the outcome through interviewed to the pavement experts to obtain the appropriate material for each pavement layer under particular design conditions. Data collected from the experts would be analysis using nonparametric statistical method to determine the ranking of each pavement material alternative prior to the development of RC-MSS. RC-MSS is developed with a prototype of an expert system using written using programming tool Microsoft Visual Basic 6.0 according the framework from the system. With this tool, better road design can also be achieved and save more time in the initial stage of on material selection, before scrutiny to laboratory test. This software would be the pioneer and provide guidance to engineers and consultants.

View full abstract

In this paper resilient behavior of asphalt concrete mixes were studied by varying temperature & time of loading to understand the pavement behavior under Pakistani climatic conditions & to address the problem according to mode of distress. The common cause of pavement distress in Pakistan is rutting, which initiates due to uncontrolled axle load & large variation in temperature. Indirect Tensile and creep tests were carried out using Universal Testing Machine (UTM 5P) on the cores taken from Islamabad-Peshawar Motorway Section (M1), IJP Principal road dual carriage way (Links Islamabad to Grand Trunk Road) & mixes prepared in the laboratory. Both sections had been opened for traffic on 2^nd, November, 2004. Polymer Modified Bitumen (PMB) has been used on M1 and is a unique opportunity to compare the behavior of in situ Asphalt Concrete mixes with & without PMB under same temperature & loading conditions. The results of laboratory tests on asphalt concrete cores (from M1 & IJP road) under the influence of load, environmental and mix variables are presented in this paper.

View full abstract