Multi-Axial Shake Table (MAST) and Data Acquisition/Control System

在地震作用下，由于结构体系的多分量地震动和地震反应，结构构件受到多轴荷载的作用。此外，土、基础和结构系统的动力相互作用在基础输入运动中产生了额外的转动和平移分量。为了充分了解多轴荷载对结构构件地震反应的影响，必须使用能够对结构试件施加多轴荷载的设备。将通过NSERC RTI计划获得的设备包括多轴振动台(MAST)和数据采集/控制系统。所要求的桅杆系统可以模拟四个自由度的地震运动，并将在未来扩展为完整的六个自由度系统。数据采集/控制系统将是桅杆和分析模型之间的接口。有了所需的设备，结构的关键部件可以用物理样本来表示，而结构的其余部分可以用数字模型来表示。使用混合模拟方法可以将这两个组件完全集成。申请的设备将用于支持NSERC发现赠款，题为“液化和土-结构-相互作用(SSI)对结构地震反应的影响调查”。在研究计划中，所要求的设备将用于开发SSI系统的混合模拟方法。此外，该设备还将用于支持其他研究项目，包括：1)垂直和水平地面运动对隔震支座响应的影响；2)多轴荷载对结构体系倒塌机理的影响；3)通过一系列小型动力试验研究等效粘滞阻尼器到滞回阻尼器的转变。利用该设备开展的研究将为结构的地震模拟提供先进的方法，并加深我们目前对结构在多轴荷载作用下的地震反应的了解，从而产生直接的社会影响。

During an earthquake event, structural elements are subjected to multi-axial loads due to the multiple components of ground motions and seismic response of a structural system. Furthermore, the dynamic interaction of soil, foundation, and structure system develops additional rotational and translational components in foundation input motion. To fully understand how the multi-axial loads affect the seismic response of structural elements, it is essential to use equipment which can apply the multi-axial loads to a structural specimen. The equipment that will be acquired through the NSERC RTI Program consists of a Multi-Axial Shake Table (MAST) and data acquisition/control system. The requested MAST system can simulate earthquake motions in four Degree of Freedoms (DOFs), and will be expandable to a full six DOFs system in the future. The data acquisition/control system will be an interface between the MAST and an analytical model. With the requested equipment a critical component of a structure can be represented by a physical specimen while the rest of the structure can be numerically modeled. The two components can be fully integrated using hybrid simulation methods. The requested equipment will be used to support the NSERC Discovery Grant entitled 'Investigation on the effects of liquefaction and soil-structure-interaction (SSI) on the seismic response of structures. Within the research program, the requested equipment will be used to develop hybrid simulation methods for SSI systems. In addition, the equipment will be used to support other research projects including: 1) the effects of vertical and horizontal ground motions on the response of isolation bearings; 2) investigation of the effects of multi-axial loading on the collapse mechanism of a structural system; and 3) investigation of the transition from equivalent viscous damping to hysteretic damping through a series of small scale dynamic experiments. The research carried out with the equipment will have a direct impact on the society by providing advanced methods for the seismic simulation of structures and by increasing our current understanding of the seismic response of structures subjected to multi-axial loads.