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Remote detection of structural aging, degradation phenomena and damage due to hazardous events is critical to ensure safety and reliability of civil or industrial structures. This is the motivation of the rapid development and increasing application of fully automated structural health monitoring (SHM) systems in civil engineering. Modal-based damage detection currently represents a popular approach for SHM of civil structures. In fact, it is a global method for damage detection and, as such, the measurement locations are not required to be close to the damage. However, damage sensitive features defined in terms of modal parameter estimates are also influenced by environmental and operational factors. Thus, neglecting this influence might jeopardize the reliability of the technology. In this framework, the present paper investigates the potential of modal-based SHM to detect earthquake damage at anchors of an atmospheric liquid storage tank. To this aim, the influences of bolt loosening at supports and of liquid level on modal parameters are investigated. The ultimate goal of the present study is the definition of criteria for the effective design and application of modal-based SHM to liquid storage tanks.

The goal of current study is to numerically investigate the dynamic response characteristics of cylindrical baffled liquid storage tank, which is subjected to a vertical acceleration at boosting, with respect to the number of baffles. Both the storage tank and baffles are modeled as flexible elastic structures, and the suppression of sloshing-induced dynamic responses by baffles are evaluated in terms of the hydrodynamic pressure, the dynamic displacement and stress. Through the numerical experiments, it has been observed that the introduction of baffles to the partially filled liquid tank remarkably decreases the maximum values of displacement and effective stress at both the bottom plate and baffles. And, the variation of displacement and effective stress is stabilized much faster when baffles are installed and the baffle number increases. Thus, it has been verified that the baffled liquid storage tank can be stably and safely applied to the liquid fuel storage tank for various transport vehicles.

Steel cylindrical tanks are widely used for the storage of hazardous substances of which leakage must be prevented under any circumstances. However, the dynamic response of the steel cylindrical liquid storage tank depends sensitively on the fluid–structure interaction and the vibration of the tank structure and necessitates clarification for the safety of the tank structure. This paper presents the results of shaking table tests performed to examine the dynamic behavior of a scaled cylindrical steel tank model considering the presence or not of fixed roof and added mass at the top of the tank for various fluid levels. The test results confirm the occurrence of both beam-type and oval-type vibration modes and show that the larger content of liquid inside the container amplified the acceleration along the height of the cylindrical tank. The oval-type vibration modes are seen to be more dominant in case of large water-to-structure mass ratio.

This study evaluates emission characteristics of volatile organic compounds (VOCs) caused by standing loss (L S) and working loss (L W) of three vertical fixed-roof p-xylene (p-X) liquid tanks during 1-year storage and filling operation. The annual net throughput of the tanks reached 70,446 t, resulting in 9,425 kg of p-X vapor emission including 5,046 kg of L S (53.54 %) and 4,379 kg of L W (46.46 %). The estimated L W of AP-42 displayed better agreement with the measured values of a VOC detector than the estimated L S of AP-42. The L S was best correlated with the liquid height of the tanks, while the L W was best correlated with the net throughput of the tanks. As a result, decreasing vapor space volume of the tanks and avoiding high net throughput of the tanks in a high ambient temperature period were considered as effective means to lessen VOC emission from the fixed-roof organic liquid storage tank.

The dynamic behavior of a liquid storage tank as a special structure differs from that of general structures. Important structures of cylindrical shape are used to store vital products, such as water and petroleum products, for cities and industrial facilities. Damage to these structures during a strong ground motion may lead to fire or other hazardous events. Liquid storage tanks are lifeline structures and strategically very important, since they have vital use in industries and nuclear power plants. In this research, an example reinforced concrete (RC) elevated water tank, with 900 cubic meters capacity, is studied under three pairs of earthquake records and analyzed in time history by using mechanical and finite element modeling techniques. The liquid mass of the tank is modeled as lumped masses known as sloshing mass, impulsive mass and rigid mass. The corresponding stiffness constants associated with these lumped masses are worked out depending upon the properties of the tank wall and liquid mass. Tank responses including base shear, overturning moment, tank displacement, and sloshing displacement under these three pairs of earthquake records are calculated, and then the results are compared and contrasted. Results show that the system responses are highly influenced by the structural parameters and the earthquake characteristics, such as frequency content.

A circular plate resting on an elastic halfspace is considered. The plate is deflected downward by a uniform load and sometimes additional edge loads and moments. Translational and rotational supports at the edge are included in some cases. The interface between the plate and the halfspace is assumed to be frictionless. The plate has piecewise-constant thickness, and the segment thicknesses and radii are allowed to vary. For given total volume of the plate, the difference between the maximum deflection (which occurs at the centre) and minimum deflection (which occurs at the edge) is minimized. Optimal solutions depend on the relative stiffness between the plate and the halfspace. The results can be applied to the bottom plate of a ground-supported liquid storage tank.

The advantages of small-scale photoelastic-model analysis of welded-steel pressure vessels are well known. The object of a current investigation is to show that similar advantages accure in the analysis of complex reinforced-concrete liquid-storage tanks. This technical note describes the planning of a tank-model experiment and the stress-freezing procedure adopted for a model loaded by glycerine.