The objective of this paper is to make clear the relationship between rate of data loss and accuracy of GPS displacement measurments. Wireless sensor network of GPS receivers might be an excellent solution for monitoring displacements of civil structures in dense. One of the important problems in wireless sensor network is power supply. To decrease the energy consumption of sensor nodes, we consider to use a low power wireless communication module. A low power wireless communication module has an advantage in energy consumption, however has an disadvantage in data loss. In this paper, we first investigate the possible rate of data loss in site experiments using a low power wireless communication module, and second simulate the accuracy of GPS displacement measurements with the possible rate of data loss.

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A series of tensile tests were conducted to investigate the tensile mechanical properties of carbon fiber, glass fiber and basalt fiber reinforced polymer sheets at temperatures ranging from 16°C to 200°C. Additionally, corresponding no-impregnated fiber sheets were tested at 16°C as a reference. The results show that the tensile strength of different fiber reinforced polymer (FRP) sheets is reduced significantly with an increase in temperature. However, the tensile strength of FRP sheets still remains a stable residual value after the polymer reaches its glass transition temperature (Tg), and this value is higher than the tensile strength of non-impregnated fiber sheets.

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This paper reports on the blind sourced econvolution of bridge vibration from the vehicle response using independent analysis.The vibration response of the vehicle passing a bridge may include bridge vibration.Thus herein, the eigenfrequecy of a bridge is estimated by the vehicle response using independent component analysis (ICA), based on the system model of a vehicle. A state space model and ARMA model is combined into system model for ICA algorithm In the experiment, a vehicle with measuremenstem passes a simple beam bridge, together with a heavy vehicle.The responses of sprung and unsprung mass are analyzed by ICA to extract the bridge vibration component.As a result, it is found that adequate degree for ARMA model must be determined to obtain bridge eigenfrequency.

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FEM analysis is a useful method of estimating the ultimate strength of damaged structures by corrosion. Actually, a large number of studies have been made on the ultimate strength of these structures by use of FEM analysis. However, most of them neglected effects of a redistribution of residual stress or dead load stress caused by volume change due to corrosion.This paper develops a finite element method that estimate the ultimate strength of corroded steel structures, and proposes a shell element that takes into consideration the change of mechanical behavior caused by volume change due to corrosion. Moreover, the effects of redistribution of residual stress or dead load stress on the ultimate strength of a steel plate are shown.

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This paper discusses determination of depth of surface crack with time domain BIEM in a laser-ultrasonic non-destructive evaluation (NDE) problems. We generate Rayleigh waves having the wavelength longer than the depth of the surfac crack with a pulsed Q-switch YAG laser gen-erator. The waveform of the scattered Rayleigh surface waves differ with the depth parameter of the surface crack in the numerical analysis. The depth parameter is then determined by a comparison between the computed waveforms and the corresponding measured data. Determi-nation of the depth of the surface crack is carried out acculately in laser-ultrasonic NDE with time domain BIEM.

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This paper proposes a method to achieve Weigh-In-Motion during traffic congestion. By analyzing strain data, the characteristics of strain during traffic congestion are acquired. This system judges traffic condition on the bridge from the time history of the minimum strain and the picture information. The picture information provides location of the vehicle. In addition, the obtained picture is used to presume the type of a car. Liner interpolation between the analyzed axle locations enables to make a similar influence line to the polynomial approximation. Finally, weight of the car traveling in slow speed is calculated.

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It is well known that important aftershocks are generally caused by large scale earthquakes. Since the damage of structure may be closely related to earthquake input energy, it is essential to evaluate accumulated energy on the structure due to aftershocks. Therefore, in order to perform the reliable performance-based design of the structure, it is important for the nonlinear response situation to perform the damage evaluations due to both the main shock and the aftershock. In this present study, the appropriate estimation on the accumulated damage of SSI system due to aftershock is examined. It is indicated that the accumulated damage estimation is closely related to the hysteresis energy of the structure due to aftershocks. It is shown that the proposed estimation method can be effectively evaluated accumulative damage due to aftershocks.

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Great possibilities to develop ocean spaces which may be used as resident areas, airports, power stations, etc. could be provided by offshore structure with a large deck area. In the presents tudy, it is examined about the dynamic response characteristics on a dual cylindrical structurec onsisting of a thin and porous outer cylinder with an impermeable inner cylinder. The evaluation of the wave force on the dual cylindrical structure, under the assumption of potential flow and linear wave theory, is carried out with an eigenfunction expansion method. It is shown that the outside cylinder with porosity plays important roles on the reduction of dynamic responses of the dual cylindrical structure for the severe wave condition.

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Lighting poles are secondary structures on bridges, but play an important part in traffic safely. In order to design lighting poles, the vibration of the bridge must be taken into account as a design loading for the poles. The dynamic response of the bridge due to time varying traffic loading must be assessed. In the present study, deconvolutional analysis is used to assess the bridge structure vibration due to traffic, and the consequent dynamic response characteristics of lighting poles. It is shown that bridge vibration plays a significant role in the reliable design of lighting pole structures.

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A surface wave analysis method is developed for half-plane, periodic structures. The wave propagation is formulated by means of the Floquet transform. By virtue of the method, the dynamic problems in an infinite domain are reduced to that in a unit cell representing the periodicity. An impedance matrix describing the relation between displacements and tractions on the surface is derived from harmonic loading of infinite periodic domain by utilizing the inverse Floquet transform. The dispersion curves are obtained by exploring the eigenvalues of the impedance matrix. To cope with the singularity encountered in the inverse transform, the integration with respect to the wave number is extended to complex number. The feasibility of the developed method is evidenced by dispersion analysis of Rayleigh waves in a homogeneous half-plane. Though some difficulties are found in the analysis for periodic structures, pass and stop bands in lower frequencies can be captured successfully.

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Secondary systems of the highway bridges such as lighting poles and information poles should resist the level-1 earthquake to acquire the serviceability of the traffic lifeline. This paper studied the bridge-lighting pole interaction during the level-1 earthquake using a precise FEM model. First, the modal analysis showed that the opening at the middle of the pole to house the electric device inside the pole reduced the twisting stiffness of the pole. Then, the earthquake response analysis showed that the precise FEM model verified the stress concentration at the opening corner. The response of the lighting pole was amplified more than 10 times because of the resonance with the bridge. Further, the effect of the mass ratio of the lighting pole and the bridge was evaluated using a two-degree-of-freedom system.

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The uplift of the flat-bottom cylindrical shell tank has been considered to contribute to the various damage of the tanks. The motion of the free surface and the fluid pressure characterize dynamical effects of the fluid on the tank induced by the uplift motion. Therefore, to properly evaluate the seismic-resistance performance of the tank, account must be made of these behaviors mathematically and numerically. The present paper examines the applicability of the explicit FE-Analysis to numerically compute these behaviors. As we shortly see, the explicit FE-Analysis accurately predicts the motion of the free surface observed during the free rocking test of the tank and the fluid pressure on the tank mathematically derived based on Laplace equation and associate boundary conditions.

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This paper presents a numerical method based on the Navier-Stokes equations to evaluate viscous forces acting on a moving body. A cell center based finite volume method for unstructured grids is applied to discretize the computational domain and solve the governing equations. A floating body with or without bilge keels undergoing roll motions at different roll angles is taken as model case. Evaluation of hydrodynamic coefficients due to viscous forces is conducted. The numerical results show that the roll-damping coefficients obtained by using the Navier-Stokes solver are larger than the radiation damping coefficients evaluated by the linear potential theory due to viscous and vortex effect.

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Flexible risers are becoming increasingly important for deep-sea oil production. In addition, current attempts directed towards global warming mitigation target the use of flexible risers for carbon dioxide injection in deep waters. The main difficulties arise from the highly nonlinear behavior and self-regulated nature of flexible risers in marine environments. This paper presents the experimental validation of a response prediction model in the quasi-steady regime. A 20-meter riser model, pinned at its both ends with a constant tension force at its top end, is sinusoidally excited at values of Keulegan-Carpenter Number located in the quasi-steady regime. Good agreement in amplitude response is obtained between experimental data and simulation results.

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Because the currently existing important industrial and civil structures were designed and constructed on the basis of the past earthquake resistant design regulations, it is important to examine the seismic response behaviors of these existing important structures by using the current knowledge on earthquake loadings and the advanced method of 3-dimensional nonlinear seismic response analysis. In this paper, the 3-dimensional nonlinear seismic response behaviors of a BFG holder have been examined using a 3-dimensional fiber element method that can make it possible to model digitally the substructures and superstructures based on the nonlinear stress-strain behaviors of the materials of the structures. The computer code of 3-D fiber element method used in this analysis can take into account for the 3-dimensional nonlinear dynamic soil foundation interaction, and also the material and geometrical nonlinear behaviors of the beam and shell elements of the BFG holder. It is found from numerical analysis that the seismic behaviors of BFG holder strongly change depending on the height (position) of the piston of the BFG holder and also the piston moves laterally and rotationally during earthquake loadings.

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Recently, application of laminated rubber bearing to multi-span continuous bridge became popular. On the other hand, consideration both of seismic load and thermal stress is very important issue for design of multi-span continuous bridge, but current specification for highway bridges doesn't request the inspection of the effect on expansion and contraction of girder caused by temperature change during earthquake. This paper presents the result of dynamic response analysis of a multi-span continuous bridge considering the effect of temperature by nodal force at the end of a girder. From the result, thermal stress has a significant impact on the dynamic response of multi-span continuous bridge.

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