Seismic Effects on Gates Westergaard’s Method of Calculation Compared to FEM Analysis and a Simplified Method Based on Local Spectra

摘要

Gates are, usually, made of welded steel structures used to adjust the water level or control water flow in reservoirs, rivers, canals, etc. There are numerous possible functions, locations and uses for these gates. Sometimes, gates must be dimensioned to withstand a possible seismic activity. There are different methods to evaluate the seismic impacts, and until now, Westergaard’s Method is most often applied in gate design. In some cases today, a seismic response spectra analysis (modal superposition method) is required by customers in the technical specifications. This method requires fluid/structure calculations which are more complex and there are no available analytical formulas that can be easily applied, thus computational finite element tools are necessary. Consequently, the dimensioning of the gate takes more time and increases the engineering costs. Moreover, the Finite Element Method doesn’t enable to easily see the sensitivity of the results further to variations of input data.