Parametric analysis of liquid storage tanks base isolated by curved surface sliding bearings

Curved surface sliding bearings, which are usually called as friction pendulum system (FPS) are commonly used for base isolation of liquid storage tanks since the period of the isolation system is independent of the storage level. However the restoring force and the damping at the isolation system are functions of axial load which changes during an earthquake excitation. This change might be in appreciable amounts especially for the tanks with high aspect ratios. The present paper focuses on earthquake performances of both broad and slender tanks base isolated by FPS bearings. The effects of overturning moment and vertical acceleration on axial load variation at the bearings are considered. The efficiency of the isolation system is investigated by analyzing the effects of various parameters such as; (i) isolation period, (ii) tank aspect ratio and (iii) coefficient of friction. The Haroun and Housner's three-degrees-of-freedom lumped mass model was used to solve the governing equations of motion in which convective, impulsive and rigid masses were included. A number of selected ground motions were considered and the results were compared to those of non-isolated cases.As a result, base isolation was found to be effective in reducing the base shear values for both broad and slender tanks without significantly affecting the sloshing displacements of the broad ones. The efficiency was even more pronounced for slender tanks subjected to near fault ground motions for isolation periods above 3 s. This specific value of isolation period also eliminated possible design problems arising from under-estimation of base shear values (up to 40%) due to ignoring the effects of axial load variation in lower isolation periods. Overturning effects should not be ignored especially for tanks with high aspect ratios (S) and being subjected to near fault ground motion.     

Dynamic sub-surface characteristic and the active faults of the Genç District locating over the Bingöl Seismic Gap of the East Anatolian Fault Zone,Eastern Turkey

The Genç District is located on the Bingöl Seismic Gap (BSG) of the Eastern Anatolian Fault Zone (EAFZ) with its?~?34.000 residents. The Karl?ova Triple Junction, where the EAFZ, the North Anatolian Fault Zone, and the Varto Fault Zone meet, is only 80 km NE of the Genç District. To make an earthquake disaster damage prediction of the Genç District, carrying a high risk of disaster, we have (1) prepared a new geological map, and (2) conducted a single-station microtremor survey. We defined that three SW-NE trending active faults of the sinistral Genç Fault Zone are cutting through the District. We have obtained dominant period (T) as?<?0.2 s, the amplification factor (A) between 8 and 10, the average shear wave velocity for the first 30 m (Vs₃₀) as?<?300 m/s, and the seismic vulnerability index (Kg) as?>?20, in the central part of the Genç District. We have also prepared damage prediction maps for three bedrock acceleration values (0.25, 0.50, 0.75 g). Our earthquake damage prediction scenarios evidenced that as the bedrock acceleration values increase, the area of soil plastic behavior expands linearly. Here we report that if the average expected peak ground acceleration value (0.55–0.625 g) is exceeded during an earthquake, significant damage would be inevitable for the central part of the Genç District where most of the schools, mosques, public buildings, and hospitals are settled-down.

     

Statistical Analysis of Storm-time TEC Variation during Ascending and Descending Solar Periods of 24th Solar Cycle

Geomagnetism and Aeronomy - This paper presents a statistical analysis of global ionospheric variation during quiet and disturbed geomagnetic conditions from December 2008 to June 2019. The study...     

Measuring the accessibility of critical facilities in the presence of hurricane-related roadway closures and an approach for predicting future roadway disruptions

Natural Hazards - Roadway closures magnify the adverse effects of disasters on people since any type of such disruption increases the emergency response travel time (ERTT), which is of central...     

判定潜在震源的模式识别方法的改进

本文给出了在非均匀网格划分的情况下,利用改进的连续Hamming方法判定潜在震源的方法和计算过程。实际计算结果表明,用此方法计算,避免了由于潜在震源形状和空间参数分配所带来的一些问题,更适用于各种形状的构造和各种形状的网格。     

聚类分析在地震场地小区划中的应用

场地地震小区划是地震小区划中重要的一环,是震害预测的基础和编制地震防灾规划的重要依据。本文用多维实测数据类似性和差异性相对识别的ISODATA聚类方法,对城市小区域场地进行了聚类分析,用数据表示了每类场地的危险程度,用计算机实现了聚类过程,从而代替了人工识别过程,使分类具有持久的客观性、可重复性和一致性。本文对天水市北道区场地进行聚类分析,结果是较理想的。     

A Comparative Study of Ozonation,Homogeneous Catalytic Ozonation,and Photocatalytic Ozonation for C.I. Reactive Red 194 Azo Dye Degradation

In this study, the decolorization, dearomatization, and mineralization efficiencies of different advanced oxidation processes (AOPs; namely O₃, O₃/Fe(II), O₃/Fe(II)/UVA, and O₃/TiO₂/UVA) were investigated for the azo dye C.I. Reactive Red 194 (RR194). The effects of pH (3–11), amount of TiO₂ (0.05–1 g/L), and concentration of Fe(II) (0.1–1.6 mM) were investigated for the applied methods. The decolorization and mineralization efficiencies of the photocatalytic ozonation system (O₃/TiO₂/UVA) were increased by decreasing the pH of the dye solution in contrast to the ozonation system (O₃). Decolorization of RR194 was increased in the photocatalytic ozonation system with an increasing amount of catalyst however, a decreasing was occurred for the homogeneous catalytic system (O₃/Fe(II)) when increasing the concentration of catalyst. The decolorization efficiency of the homogeneous catalytic system (O₃/Fe(II)) was enhanced when combined with UVA light. In our study, the most efficient method for dearomatization and mineralization was the O₃/TiO₂/UVA among the applied AOPs.