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This paper presents the case study of a collapsed riverbank protection structure, located in the curvature of the watershed along the Pasak river in Saraburi province, Thailand. Although efforts have been made to twice rehabilitate this collapsed structure, the rebuilt protection structures were unstable to prevent progressive collapse damage and the causes of their failure remained elusive. The project team was engaged to carried out the site investigation and finite element analysis prior to providing the remedial approach on the collapsed structure. The outcome from this study reveals that the natural disaster events were the main causes of the structure failure. During the rainy season, water flowed into the river from upstream farmlands by crossing the backfill of the riverbank protection structure. Seepage forces were thus developed in the direction of inflows, which resulted in reduced stability of the riverbank protection structure. Furthermore, the strong currents in the river continuously scoured the banks, undermining the natural slope in front of the riverbank protection structure, resulting in soil erosion in the passive zone and instability of the protection structure. Based on these two causes of failure, a remedial solution was devised using a new bored pile riverbank protection structure with the usage of geocomposites and ripraps. Geocomposites and ripraps were installed at the back and front of the bored pile walls to relieve the structure from seepage forces and to prevent soil erosion, respectively. An adequate factor of safety against the external and internal failure of the new riverbank protection structure was verified by finite element modeling and the results confirmed that the structure was safe. [ABSTRACT FROM AUTHOR]

• This paper presents a non-contact approach for a large-scale cable tension evaluation. • The presented non-contact approach is based on 3D laser scanning data. • An actual case study of the long-span roof cable of a big exhibition center in Thailand is performed to show the effectiveness of the presented approach. • The presented non-contact approach yields satisfactory results compared with a conventional method by measuring the cable's natural frequency. This study proposes a non-contact approach for tension evaluation of a large-scale cable-stayed roof. Three-dimensional (3D) laser scanning data based on a terrestrial laser scanner are utilized to explore the current cable configuration in 3D. Subsequent analysis of the exact current cable configuration indicates that the cable tension can be evaluated by minimizing the cable configuration error. The precise cable tension, which correlates with the actual cable configuration, is determined using nonlinear finite element analysis which is based on a model formulation that considers the effect of bending rigidity. The proposed method is verified by experimental studies. A case study is performed of the long-span roof cable of a large exhibition center in Thailand to demonstrate the effectiveness of this approach in comparison with the natural frequency measurement-based method. The results show that the proposed method is an alternative non-contact approach for evaluating cable tension with reasonable accuracy. [ABSTRACT FROM AUTHOR]

Abstract: A comprehensive set of experimental data on Bangkok subsoils from oedometer and triaxial tests are analysed in this paper in order to determine the stiffness and strength parameters for Hardening Soil Model. The parameters determined are the Mohr–Coulomb effective stress strength parameters together with the stiffness parameters; tangent stiffness for primary oedometer loading, secant stiffness in undrained and drained triaxial tests, unloading/reloading stiffness and the power for stress level dependency of stiffness. The oedometer data are obtained from three different Bangkok soil layers: soft clay at 6–8m depths; medium clay at 12–14m depths; and stiff clay at 15.5–18m depths. The triaxial tests data are carried out for soft and stiff clays at depths of 5.5–6m and of 16–18m under both undrained and drained conditions, respectively. Finally, two sets of parameters for soft and stiff Bangkok clays are numerically calibrated against undrained and drained triaxial results using PLAXIS finite element software. [Copyright &y& Elsevier]

Abstract: Litchi (Litchi Chinensis Sonn.) is an important commercial fruit in Thailand and Vietnam. Litchi fruit is consumed both as fresh and dried products. Also most of the export of litchi is in the form of dried whole litchi fruit. Thermo-physical properties and drying model of litchi fruit is important for optimum design of litchi dryer. This paper presents moisture diffusivity, shrinkage and finite element simulated drying of litchi fruit. The moisture diffusivities of litchi were determined by minimizing the sum of square of deviations between the predicted and experimental values of moisture content of thin layer drying under controlled conditions of air temperature and relative humidity. The components in the form of cylinder for seed and seed stalk and slab for seed coat, shell and flesh were dried in thin layers at the air temperatures of 50, 60, 70 and 80°C and relative humidity in the range of 10–25%. The mean diffusivity of flesh, seed and shell of litchi fruit increased with temperature and was expressed by the Arrhenius-type equation, but the diffusivities of seed coat and seed stalk were independent of temperature. The moisture diffusivities of seed coat and seed stalk were much lower than those of the other parts of the litchi. The shrinkage of litchi fruit has also been determined experimentally and it was expressed as a function of moisture reduction. A two-dimensional finite element model has been developed to simulate moisture diffusion in litchi fruit during drying. Shrinkage of the flesh and different component diffusivities of litchi during drying were also taken into account. The finite element model was programmed in Compaq Visual FORTRAN version 6.5. This finite element model satisfactorily predicts the moisture diffusion during drying. Moisture contents in the different components in the litchi fruit during drying were also simulated. This study provides an understanding of the transport processes in the different components of the litchi fruit. [Copyright &y& Elsevier]

Abstract: In this paper two different numerical approaches for consolidation in porous media are developed and thoroughly compared: Galerkin finite element method (GFEM) and least-squares mixed finite element methods (LS-MFEM). The primary variables of the GFEM are fluid pressure and solid displacement. Fluid fluxes and stresses are derived quantities. In the LS-MFEM method all four unknown functions are primary variables, which results in more accurate approximations of fluid fluxes and stresses. Results of both numerical methods are compared for two examples. The first example, for which an analytical solution is known, is used in order to verify the implementation of the numerical schemes. In the second example, for a footing problem which was proposed by Murad et al. [M. Murad, V. Thomée, A. Loula, Asymptotic behavior of semidiscrete finite-element approximations of Biot’s consolidation problem, SIAM J. Numer. Anal., 33 (1996) 1065–1083], a detailed numerical analysis and comparison of both schemes are presented. [Copyright &y& Elsevier]