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Transport, Thailand

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Transport, Thailand
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Gu P.,Tongji University | Zhang Z.-Q.,Tongji University | Hu Y.-J.,Bureau of Planning | Zhou S.-N.,Tongji University
Bridge Construction | Year: 2017

To study the influences of the U rib inner diaphragms and their parameters on the fatigue performance of the orthotropic steel bridge deck plate, a railway bridge of the rigid steel truss girder and flexible arch was cited as an example, 2 full-scale models (the specimen 1 of the models had no inner diaphragms while the specimen 2 had) for the deck plate of the bridge were fabricated, the fatigue tests were carried out and the occurrence of the fatigue cracks was studied. The finite element models were also set up, using the software ANSYS and the stress distribution at the longitudinal rib webs where the cracks occurred was analyzed. The fatigue life of the deck plate was assessed, using the fracture mechanics method and the influences of the parameters of the inner diaphragms on the stresses of the deck plate were analyzed. The results demonstrate that at the junctures of the longitudinal rib webs and the cross beam cap holes, the fatigue cracks are prone to occurring and the cracks of the 2 specimens all occur at such junctures. The arrangement of the longitudinal rib inner diaphragms can improve the stress concentration and effectively enhance the fatigue strength at the junctures. The influences of the thickness of the inner diaphragms on the stresses of the deck plate are not great and the appropriate increase of the height differences of the inner diaphragms can reduce the principal stresses at the longitudinal rib webs. © 2017, Journal Press, China Railway Bridge Science. All right reserved.

Tunsakul J.,King Mongkut's University of Technology Thonburi | Jongpradist P.,King Mongkut's University of Technology Thonburi | Soparat P.,Bureau of Planning | Kongkitkul W.,King Mongkut's University of Technology Thonburi | Nanakorn P.,Thammasat University
Computers and Geotechnics | Year: 2014

Fractures developed around high pressurized gas or air storage tunnels can progressively extend to the ground surface, eventually leading to an uplift failure. A tool reasonably reproducing the failure patterns is necessary for stability assessment. In this study, a numerical method based on the element-free Galerkin (EFG) method with a cohesive crack model is developed to simulate fracture propagation patterns in the rock mass around a tunnel under high internal pressure. A series of physical model tests was also conducted to validate the reliability of the developed method. A qualitative agreement between physical model tests and numerical results can be obtained. The in situ stress ratio, k, has a strong influence on both the position of crack initiation and the propagation direction. The numerical analyses were extended to full-scale problems. Numerical tests were performed to investigate the prime influencing factors on the failure patterns of a high pressurized gas circular tunnel with varying parameters. The results suggest that initial in situ stress conditions with a high k (larger than 1) is favorable for construction of pressurized gas or air storage tunnels. © 2013 Elsevier Ltd.

Chen A.,Utah State University | Chen A.,Tongji University | Pravinvongvuth S.,Expressway Authority of Thailand | Xu X.,Utah State University | And 3 more authors.
Transportation Research Part A: Policy and Practice | Year: 2012

The purpose of this paper is to examine the scaling effect and overlapping problem in a route choice context using the logit-based stochastic user equilibrium (SUE) principle to explicitly account for the congestion effect. Numerical experiments are performed on nine models: the deterministic user equilibrium model, the multinomial logit SUE model with and without scaling, the C-logit SUE model with and without scaling, the path-size logit SUE model with and without scaling, and the paired combinatorial logit SUE model with and without scaling. Sensitivity analysis is conducted to examine the effects of route sets, congestion levels, dispersion intensities, and network asymmetries. A real transportation network in the City of Winnipeg, Canada is also used to compare the network equilibrium flow allocations of different SUE models. The results of the sensitivity analysis and the Winnipeg network reveal that both scaling effect and overlapping problem can have a significant impact on the network equilibrium flow allocations. © 2012.

Kongkitkul W.,King Mongkut's University of Technology Bangkok | Punthutaecha K.,Bureau of Road Maintenance | Youwai S.,King Mongkut's University of Technology Bangkok | Jongpradist P.,King Mongkut's University of Technology Bangkok | And 4 more authors.
Transportation Research Record | Year: 2011

Even though low-volume roads usually serve as secondary roads on the entire road network, they are of great importance for the distribution of goods to a number of rural areas in Thailand. However, the budgets for evaluation of the physical condition of the pavement structure of roads in this category and for their subsequent maintenance are surprisingly limited. In addition, the number of specialists required to perform visual inspections is small, and simple static tests on road surfaces are time-consuming and thus expensive. Consequently, it is difficult, if not impossible, to evaluate the physical conditions of pavement structures at a sufficient number of locations. To mitigate this, it becomes necessary to develop a simple test device and a simple means of test analysis to evaluate the physical condition of the pavement structure. This paper introduces a dynamic hammer and discusses a procedure for analysis of the test data. Experiments were performed on both asphalt-paved and unpaved surfaces, which are usually used for low-volume roads. In addition, plate load tests were performed in parallel to compare the test results and validate the analytical framework. It was found that the test device and the framework for analysis of the test data presented in this paper are relevant for use, in particular because of the simplicity of device production, the ease of device use, the time-effectiveness of test performance, and the procedures used for data analysis. Therefore, maintenance can be performed at sufficient numbers of locations of low-volume roads to keep them in good physical condition for serving the entire road network.

Paraphantakul C.,Bureau of Planning | Miller-Hooks E.,University of Maryland University College | Opasanon S.,Thammasat University
Transportation Research Record | Year: 2012

The problem of truckload delivery with backhaul scheduling was formulated, and a methodology for ant colony optimization that was developed for a related problem, the problem of vehicle routing with backhaul and time windows, was adapted for the solution of the truckload delivery problem. The problem of truckload delivery with backhaul scheduling differs from the problem of vehicle routing with backhaul and time windows in that shipments are in units of truckloads, multiple time windows in multiple days are available for delivery to customers, limited space for servicing customers is available, and multiple visits to each customer may be required. The problem is motivated by a real-world application arising at a leading cement producer in Thailand. Experts at the cement production plant assign vehicles to cement customers and lignite mines on the basis of manual computations and experience. Mathematical and computational frameworks are provided for modeling and solving this real-world application.

Wu W.,South China University of Technology | Wu W.,Guangzhou University | Zheng Y.,Bureau of Planning
Advanced Materials Research | Year: 2012

Mixed-use industrial park represents a new development approach of the modern industrial parks. Complying with this tendency, the land use planning of Sino-Singapore Guangzhou Knowledge City (SSGKC) proposes land relevance, non-interference and proportion control principles; discusses various mixing-use modes of commercial service land, residential land and industrial land. The plan also put forward a new type of cluster using layout to enhance the mixed land uses and eventually shape up a new industrial park that well integrates city with Industrial Park and industry with residence. © (2012) Trans Tech Publications, Switzerland.

Chen A.,Utah State University | Chootinan P.,Bureau of Planning | Ryu S.,Utah State University | Wong S.C.,University of Hong Kong
Journal of Transportation Engineering | Year: 2012

The goals of this paper are to (1) provide a review of the recently developed measures for assessing the quality of origindestination (O-D) trip tables estimated from traffic counts and (2) propose a new generalized demand scale (GDS) measure. This GDS quality measure generalizes the total demand scale (TDS) quality measure by allowing the assessment of the intrinsic underdeterminant problem of O-D estimation from traffic counts at various spatial levels. Numerical examples are provided to compare the proposed GDS measure with the TDS measure, the maximal possible relative error, and the expected relative error and to illustrate the features of the GDS measure. © 2012 American Society of Civil Engineers.

Chen A.,Utah State University | Chootinan P.,Bureau of Planning | Ryu S.,Utah State University | Lee M.,University of Alaska Fairbanks | Recker W.,University of California at Irvine
Journal of Advanced Transportation | Year: 2012

Estimation of intersection turning movements is one of the key inputs required for a variety of transportation analysis, including intersection geometric design, signal timing design, traffic impact assessment, and transportation planning. Conventional approaches that use manual techniques for estimation of turning movements are insensitive to congestion. The drawbacks of the manual techniques can be amended by integrating a network traffic model with a computation procedure capable of estimating turning movements from a set of link traffic counts and intersection turning movement counts. This study proposes using the path flow estimator, originally used to estimate path flows (hence origin-destination flows), to derive not only complete link flows, but also turning movements for the whole road network given some counts at selected roads and intersections. Two case studies using actual traffic counts are used to demonstrate the proposed intersection turning movement estimation procedure. © 2010 John Wiley & Sons, Ltd.

Chen A.,Utah State University | Pravinvongvuth S.,DKS Associates | Chootinan P.,Bureau of Planning
Transportmetrica | Year: 2010

Recently, a multi-objective model for locating the automatic vehicle identification (AVI) readers in a transportation network was proposed by the authors along with its solution procedure. The model locates the AVI readers by simultaneously considering three objectives: the equipment and installation cost (e.g. number of AVI readers), the coverage of the AVI system (e.g. number of origin-destination (O-D) pairs), and the amount/quality of travel information obtained (e.g. number of AVI readings). However, only a single travel demand pattern for a certain time period, such as the evening peak hour, was considered in determining the AVI reader locations. Therefore, the recommended AVI system may not be able to guarantee the amount of travel information gathered during other time periods. This study extends our previously proposed model by developing three scenario based models to accommodate different travel demand patterns observed during the whole day. A case study is provided to illustrate the applicability of the new models and the robustness of the AVI system designed by considering different travel demand patterns. © 2010 Hong Kong Society for Transportation Studies Limited.

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