بررسي تجربي اثر تيغه هاي فولادي در كاهش ارتفاع موج سيال در مخازن استوانه ‌يي فولادي روزميني به كمك آزمايش ميز لرزان

Shaking table study on the Effect of Baffle in Sloshing Reduction in Aboveground Steel Storage Tanks

هدف از اين پژوهش، مطالعه‌ي كاهش ارتفاع تلاطم سيال در مخازن ذخيره‌ي فولادي روزميني با استفاده از تيغه هاي ميراگر فولادي حلقوي (بفل) است، كه به ديواره‌ي مخزن متصل شده باشند. در اين پژوهش، يك مخزن نمونه‌ي مقياس‌شده با ضريب مقياس هندسي (1:16=L?) به عنوان نماينده‌ي مخازن مهارشده مورد بررسي آزمايشگاهي روي ميز لرزان قرار گرفته است، كه در آن نسبت ارتفاع سيال به قطر مخزن متفاوت در نظر گرفته شده است. آزمايش‌ها به‌وسيله‌ي ميز لرزان در حالات با و بدون حضور بفل صورت پذيرفته است. سه ركورد زلزله‌ي واقعي پس از مقياس بندي به عنوان تحريك ورودي مدل توسط ميز لرزان توليد شده است. نتايج اين پژوهش نشان مي دهد كه بفل ها آثار قابل ملاحظه ‌يي در كاهش ارتفاع تلاطم سيال دارند، و بنابراين به عنوان ميراگرهاي متغير در مخازن موردنظر قابل استفاده هستند.

Oil storage tanks are used extensively in different national industries such as refineries, power plants and fuel storage facilities. Therefore, the seismic safety and stability of this kind of tank during strong earthquakes are very important. Many existing tanks are designed, constructed and operated based on outdated versions of standards and code requirements. Therefore, investigation into existing tanks using the latest versions of international standards and their retrofitting is necessary. In this study, reducing fluid wave sloshing height in steel storage tanks using an annular baffle as a damping device installed on the tank shell is investigated. Based on the widespread use of baffles in moving liquid containers, especially in space vehicles, the ability of baffles to reduce sloshing effects in storage tanks that are especially broader than fuel containers is under question. The primary objective of the shake table study made in this research is to provide test data for verification of numerical models and to recommend a practical baffle arrangement that would be effective over a range of frequencies. For this purpose, a typical tank model with a geometrical scaling of 1/16 is considered in this research as representative of anchored tanks with different height to diameter ratios. At the Laboratory of the International Institute of Earthquake Engineering and Seismology (IIEES) in Tehran, a shaking table test was undertaken to evaluate sloshing wave amplitudes in scaled model steel storage tanks in cases of with and without annular baffles. Three earthquake ground motion records are used as input base motions to the studied tank model generated by the shaking table. Four different liquid filling levels and 3 types of baffle arrangement are used to investigate the effect of the number and location of baffles on sloshing amplitude reduction during the earthquake in the studied tank model. The results of studied models indicate that the annular baffles have significant effects in reducing sloshing wave height as sloshing dependent dampers, and can be used in oil storage tanks.