Ensuring the safe operation of large LNG storage tank projects under blast loads is very important. First, using LS-DYNA software, numerical simulations of air blast wave propagation are studied with the ALE algorithm and fluid-solid coupling theory. A new corrected formula for the peak overpressure is proposed based on the numerical results, and its accuracy is verified by comparing the numerical results with the empirical formula and test results. Then, a finite element model of a large LNG storage tank is built, assuming that the explosion source is located 10 m away from both the ground and the tank wall. This model is used to analyse the overpressure and dynamic response of the outer concrete tank and to predict the TNT equivalent quantity that the tank can withstand. The results show that the tank wall facing the burst loads is in a more dangerous state and that the principal tensile stress increases approximately linearly with increasing TNT equivalent quantity. When the TNT equivalent quantity reaches 2.5 t, concrete element failure occurs on the centre facing the explosions, and the outer tank structure is damaged. The conclusions can provide a reference for the blast-resistant design of large LNG storage tanks.

The present paper investigates the mechanical behavior of buried steel pipelines crossing an active fault. Permanent ground deformation induced by an earthquake will cause serious damage to buried steel pipelines, resulting in buckling failure or even cracking damage to pipelines. Based on ABAQUS software, version 6.13., the model of an interacting soil–pipeline system is established, accounting for large strains and displacements and nonlinear material behavior, as well as contact and friction at the soil–pipeline interface. Numerical analysis is conducted through the incremental application of fault displacement. Combined with the force and deformation characteristics of buried pipelines, a strain-based design criterion is chosen to study the vertical displacement, axial compressive, and tensile strain of buried pipelines, etc. This paper focuses on the effects of horizontal fault displacement, fault type, and fault angle on the structural response of the pipe. The failure of the pipeline, such as wall wrinkling, local buckling, or rupture is identified. Furthermore, the effects of the pipeline internal pressure and pipe wall thickness are investigated. The results show that, when the pipeline depth is 1.5 m under the action of the fault, the buried pipeline will not be subject to beam buckling damage, and both tensile damage and shell buckling damage will occur. In this case, the critical displacement of the tensile failure is more than three times that of the shell buckling failure, which indicates that shell buckling damage is a greater threat to the pipeline. The pipeline is most susceptible to damage under the action of a strike-slip reverse fault. When the fault angle is equal to 45 degrees, the pipeline is more likely to be damaged, while it is relatively safe at a fault angle with 90 degrees. The results of this investigation can determine the fault displacement during pipeline failure and provide some reference for pipeline design.

This paper investigates the effect of the multi-directional components of ground motion on an unanchored steel storage tank. Both the liquid sloshing effect and contact behavior between the foundation and tank are included in the study. A three-dimensional model for a foundation–structure–liquid system is numerically simulated using the finite element method. The Lagrange fluid finite element method (FEM) in ANSYS is used to consider the liquid–solid interaction. In the liquid–structure–foundation interaction model, the contact and target elements are adapted to simulate the nonlinear uplift and slip effects between the tank and the foundation. Three earthquake ground motions are selected for evaluating the seismic behavior of the tank. Comparisons are made on the horizontal displacement, “elephant-foot” deformation, stress, base shear and moment, sloshing of the liquid, uplift, as well as slip behavior under the application of the unidirectional, bi-directional and tri-directional components. Under the selected ground motions, the horizontal bi-directional seismic component has great influence on the liquid sloshing in the tank studied in this paper. The vertical seismic component produces high compressive axial stress, and it also makes the uplift and slide of the tank bottom increase significantly. The applicability of this conclusion should be carefully considered when applied to other types of ground motion inputs.

The structure-soil-structure interaction (SSSI) between high-rise buildings is numerically investigated. ANSYS has been further developed for calculation in the frequency domain, in which hysteretic damping can be considered for both the soil and structure. This study is presented in two subsequent papers. In the first part, i.e., this paper, the variations in the story shear force, interstory drift angle, displacement, velocity and acceleration of the superstructure, the sway of the foundation, and the axial and shearing forces of the pile are presented. The major influencing factors are the excitation frequency of a harmonic wave or the frequency components of a seismic wave, shaking direction of an exciting wave and direction of the structure arrangement. Under harmonic waves, the interaction mainly occurs when the excitation frequency is 1-5 Hz. Under seismic waves, when the shaking direction of an exciting wave is perpendicular to the direction of the structure arrangement and the direction of the structure arrangement is parallel to the lateral axis of the structure, the influence on the superstructure is greatest.

A numerical study is performed on the structure-soil-structure interaction (SSSI) between high-rise buildings. ANSYS has been further developed for calculation in the frequency domain, in which hysteretic damping can be considered for both soil and structures. This study is presented in two subsequent papers. The first part[1] focuses on the influence of the SSSI on each kind of dynamic response, while the second part, i.e., this paper, is a parameter study that focuses on the influence of each key parameter, including the separation distance between structures; the damping ratio, thickness and shear wave velocity of the soil; the length of the pile; the damping ratio, style, material stiffness, mass and story number of the superstructure; and the position and number of the structure, on the SSSI. The interaction decreases with the increase in the separation distance between structures, the increase in the damping ratio and shear wave velocity of the soil, the increase in the damping ratio and mass of the superstructure, or the decrease in the material stiffness of the superstructure in a fluctuating manner.