Based on branch substructure method, this article deduces motion equation of an equipment–structure–soil interaction system. The equation is converted and applied to a shaking table real-time subst...

A shaking table real-time substructure experiment of an equipment–structure–soil interaction system:

Equation of motion for an equipment-structure-soil (ESS) interaction system was derived using the branch substructure method. After rearrangement, this equation was applied to real-time dynamic substructuring shaking table (RTDSST) testing of the ESS system. This method adopts the equipment-structure (ES) subsystem as the experimental substructure and a modal reduced soil model as the numerical substructure: the former is tested via the shaking table, and the latter is numerically simulated, while real-time data communication occurs between the two substructures during testing. A scale model of the ESS system was designed and underwent an RTDSST test. The experimental data were found to be consistent with the numerical calculation results, which corroborates the reliability and validity of the proposed testing method. A comparison of the experimental results from different earthquake stages implies that seismic responses of the equipment and structure decreased in general due to the intervention of soil, but the soil effect weakened with earthquake intensity.

/pdf/effects-of-equipment-structure-soil-interaction-on-seismic-13rm9b8537.pdf

Effects of Equipment-Structure-Soil Interaction on Seismic Response of Equipment and Structure via Real-Time Dynamic Substructuring Shaking Table Testing

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 (Ω) 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 Ω 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 Ω 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.

/pdf/inelastic-parametric-analysis-of-frequencies-and-seismic-2pqgghp1az.pdf

Inelastic parametric analysis of frequencies and seismic responses of soil-multistorey bidirectional eccentric structure interaction system

This study investigated the real-time substructure shaking table testing (RTSSTT) of an equipment-structure-soil (ESS) system and the effects of soil on the seismic energy responses of the equipment-structure (ES) subsystem. First, the branch modal substructure approach was employed to derive the formulas needed for the RTSSTT of the ESS system. Then, individual equations for calculating the energy responses of the equipment and the structure were provided. The ES subsystem was adopted as the experimental substructure, whereas the reduced soil model was treated as the numerical substructure when the RTSSTT was performed on the ESS system. The effectiveness of the proposed testing method was demonstrated by comparing the test results with those of the integrated finite element analysis. The energy responses of the ES subsystem in the case of rigid ground (i.e., the ES system) were compared with those considering the effects of soil (i.e., the ESS system). The input energy responses of the ES subsystem were found to decrease significantly after taking the effects of soil into account. Differences due to the soil effects should be considered in the seismic design for the ES system.

/pdf/analysis-of-the-effects-of-soil-on-the-seismic-energy-4rk21i96k4.pdf

Analysis of the Effects of Soil on the Seismic Energy Responses of an Equipment-Structure System via Substructure Shaking Table Testing

This article presents a parametric study on the lateral-torsional coupling behaviour of the simplified bidirectional asymmetric multi-storey dual lateral load-resisting model. The implementation process for establishing the simplification model is shown in an illustrative example on a three-storey reinforced concrete building system. Combined with the force–displacement relationships of the lateral load-resisting members and the inter-story restoring force models, the dynamic stiffness matrix and the equations of motion under different loading conditions can also be determined. On this basis, parametric analyses for the systems are carried out through the whole loading process from the elastic stage to the inelastic stage. Effects of uncoupled torsion to lateral frequency ratios (Ω) and the stiffness eccentricities on the frequencies are investigated. The analysis shows that the asymmetrical system with a smaller Ω value has a smaller torsional stiffness and a stronger lateral-torsional coupling effect. T...

Xinliang Jiang

Papers

Parametric analysis of eccentric structure–soil interaction system based on branch mode decoupling method