In this paper, the result of application of this simple method of vibration analysis developed by the author, to the special orthotropic plates with variable cross-section, and with a pair of opposite edges simple supported and the other pair of opposite edges free is presented. This problem represents the simple-supported single span bridge system without effective longitudinal edge beams. The effect of concentrated point mass/masses is also studied.

Theories of advanced composite structures are too difficult for such field engineers and some simple methods are necessary. In this paper, Simple method of vibration analysis is presented. This method presented in this paper is studied self-weight and other loads. The result of the 2~3 times iteration is good enough for field engineering purposes. In the case of cantilevered composite materials beams with different cross section, increase of mass near the support does not significantly affect the vibration characteristics. As a calculations of the simple method of vibration analysis for cantilevered composite materials beams with different cross section, it is noted that the result of the second cycle at the point of free end (actually 5L/6 span) is only 2.2% away from the ‘exact’ solution.

If deposits occur around the dam, it is possible to suspect the erosion of the internal material of the dam. Piping can occur if the dam internal material is eroded, and such piping can be a serious safety hazard for the dam. XRD and XRF were performed on the investigated sediments and dam core materials. XRD and XRF were carried out to confirm the constituent minerals and chemical composition of the samples. This method can be applied to detect the possibility of erosion of the material constituting the dam.

Measurement items of phenomena reflecting the overall condition of the structure during the measurement for safety management in the dam include water volume and displacement depending on the number of water leaks. Leakage measurements, which are important indicators to be measured on a dam, require significant accuracy and reliability. However, the dam design basis includes general measurement equipment, but the lower the limit for calculating the water leakage, and the lack of accuracy and reliability is a phenomenon. Therefore, in order to improve accuracy and reliability of the dam's major measurement items, the standards of the dam water measuring meter and the suitability of the water leak calculation formula (based on USBR) are reviewed to elicit problems and suggest solutions.

This study compared the result applying two analysis methods based on Newmark Sliding Block theory to calculate permanent displacement that is an estimating factor for seismic safety of Fill Dam. It was analyzed FEM numerical coupled-analysis and Makdisi-Seed method. The permanent displacement for the body of dam during earthquake indicated similar displacements with each of them at the same seismic load.

In this paper, the method of vibration analysis for calculating the natural frequency is presented. This method is a simple but exact method of calculating natural frequencies corresponding to the modes of vibration for the cantilevered composite materials beam. As a calculations of the method of vibration analysis, it is noted that the result of the second cycle is only 2.2% away from the ‘exact’ result. In the case of cantilevered composite materials beam, increase of mass near the support does not significantly affect the vibration characteristics. This method may be extended to stability analysis of complex structural elements.