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An experimental protocol was developed to predict the service period of polyethylene pipes under high loads. This paper presents the results of field test of chimney demolition loading to polyethylene pipeline, and compared with the numerical simulation. Combined with the practical engineering situation, the ground impact load first propagates to the explosion-facing side of the pipeline, and the effect was found to decrease as the applied stress decreased, however, under high impact load, ring strain tends to be greater than axial strain. The test data such as vibration velocity and frequency are processed to determine the damage characteristics needed to protect the pipeline from damage. Finally, the safety assessment of pipeline under impact load was determined by yield criterion [ABSTRACT FROM AUTHOR]

With the development of urbanization, the construction of the subway has been greatly developed. Meanwhile, the public concern of terrorist attacks on subway stations keeps driving the related research. In this paper, the representative subway station of Wuhan Metro Line 8, Mafangshan station, which is now under construction, is taken as a case, the dynamic finite element numerical simulation software ANSYS/LS-DYNA is employed to establish finite element model. The propagation law transmitting through the station structure and the dynamic response of the station under different TNT charges are analyzed. It is indicated that the propagation of shock wave is complicated due to the semi-closed environment of the station as well as the reflection and transmission of the stress wave in the structure. Specifically, in the station structure, the displacement of the platform plate was the largest, under the explosive action of different TNT charge, the displacement of platform plate is 13.6 mm (5 kg), 22. 8mm (10 kg), 35.2 mm (20 kg), 45.6 cm (30 kg), 68.8 cm (40 kg), respectively. The middle part of the pillar was the largest displacement on the pillar. Based on the dynamic stress response analysis of the station pillar, it shows that the maximum value of the stress value in the pillar is located at the junction of the pillar and the plate. Under the explosive action of 40 kg TNT charge, the maximum tensile stress of the junction of the pillar and the plate reached 45.1 MPa. Therefore, more attention should be paid to anti-explosion measures herein. Besides, through the analysis of the tensile stress value at the bottom of the pillar under different charge quantity, the TNT charge quantity for the crack at the bottom of the pillar is determined to be 6.77 kg by the formula fitting. [ABSTRACT FROM AUTHOR]

As the buried gas pipelines are not easily field monitored, its status under the influence of tunnel blasting vibration is often difficult to obtain. In order to assess the safety of an upper buried gas pipeline under blasting vibration in the Beijing subway line 16, we established the 3D numerical model of the real field engineering to calculate and analyze the distribution of peak particle velocity (PPV) on the surface soil, proved its reliability by using the field monitoring data and discussed the dynamic response of the pipeline. Based on the analysis, we further assessed the safety of pipeline subjected to tunnel blasting vibration and concluded that the pipeline is only subjected to limited effect of tunnel blasting vibration and thus is safe. [ABSTRACT FROM AUTHOR]

The concept of inertia coupling terms among substructures was proposed. Based on the branch mode method, the superstructures and foundation soil of one soil-adjacent structure system were divided into different branches. The branch mode method was effectively introduced to real-time dynamic substructure testing (RTDST) by decomposing and transforming the motion equation of the entire system. It was also applied for the interaction coupling terms to exchange data between the physical and numerical substructures. This method decreased the degree-of-freedom of the linear substructure effectively and considered the effects of foundation translation and rotation on the upper structures. One system composed of two adjacent four-story steel structures (S1 and S2, respectively) and foundation soil was presented in this study. S1 was applied on a shaking table as the physical substructure, whereas the foundation soil and S2 were set as two numerical substructures and simulated in a computer. The seismic response of the entire coupling system was analyzed by real-time data exchange among substructures. Test results agree with numerical solutions. The RTDST based on the branch mode method is a feasible and reliable method for the investigation of soil-adjacent structure interaction (SASI) problems, and provides a new way to consider SASI problems in the RTDST. [ABSTRACT FROM AUTHOR]

This paper presents a parametric study on the lateral-torsional coupling behaviours of soil-multistorey bidirectional eccentric structure interaction system from elastic stage to nonlinear inelastic stage. A simplified bidirectional eccentric multistorey dual lateral load-resisting model for the superstructure is proposed to conduct this parametric study. Incorporating the inter-storey restoring force model of the superstructure, the dynamic motion equations and the dynamic stiffness matrix of the soil-multistorey bidirectional eccentric structure interaction system in different loading stages are derived. Based on these, parametric analyses of frequencies and seismic responses for the soil-three storey structure interaction systems from elastic stage to nonlinear inelastic stage are evaluated. Effects of the uncoupled torsion to lateral frequency ratios (O) of the corresponding fixed base system, the stiffness eccentricities and different soil types on the frequencies and seismic responses are investigated. Results show that the soil can significantly reduce the lateral-torsional coupling effect and the structural seismic response of the soil-bidirectional eccentric structure interaction system; a smaller O value and larger values of the eccentricities lead to a larger reduction in the lateral-torsional coupling effect of the first order mode in nonlinear inelastic stage; the effects of different foundation conditions on the structural seismic responses are weakened by the development of structural inelastic; after considering the soil-structure interaction, the influences of O and eccentricities on the structural seismic responses are changed. A softer soil-structure interaction system has a more weaken lateral-torsional coupling effect, and its vibration modes in nonlinear inelastic stage are changed compared with the system situated on other soils. [ABSTRACT FROM AUTHOR]