Dynamic characteristics and viscous dampers design for pile‐soil‐structure system

Abstract

Summary A series of large‐scale shaking table tests are conducted on tall buildings with and without energy dissipation devices on soft soils in pile group foundations, representing pile‐soil‐structure interaction (PSSI) system and the corresponding fixed‐base situations. The superstructure is a 12‐story reinforced concrete (RC) frame. The dynamic characteristics of the test models show that the frequencies decrease and the damping ratio increase in PSSI system by comparison with the fixed‐base structures. The mode shapes of PSSI system are different from that under fixed‐base condition, and the mode shapes of structure without dampers change greater than that with energy dissipation devices under various white noises. An improved method for structural dynamic characteristics, considering the impedance function of piles, is developed to address the issue of modal parameters with PSSI effect. In addition, the structural dynamic parameters of the large‐scale shaking table tests are identified using the modification method and other regulation methods, demonstrating that the improved approach is highly accurate and effective. Subsequently, a design procedure for viscous dampers of structures with PSSI effect is presented based on the dynamic characteristics of the system. Finally, the dynamic responses of the structure with viscous dampers in the practical engineering are decreased effectively, indicating the good performance of designed viscous dampers. The numerical results also show that the damping efficiency of interstory drift is larger than the acceleration and interstory shear force. Therefore, the improved modal parameters method, validated through a series large‐scale shaking table tests, is applicable for identifying dynamic characteristics of pile‐soil‐structure with energy dissipation devices system. The design procedure of viscous dampers, proved by a reinforced concrete frame structure located on a practical Shanghai soft site, can be employed to design the viscous dampers considering seismic PSSI effect.

The Dynamic Behavior of Silos with Grain-like Material during Earthquakes

“…However, there are many influencing factors, such as the stiffness of the silo, the height-todiameter ratio, the physical properties of the storage materials, the vibration frequency, the friction between the stock and the silo wall, etc. [31][32][33][34]. At present, the evaluation of the quality coefficient is not very accurate.…”

Experimental and Numerical Investigation of Plastic–Concrete Waterproof Walls of an Underground Granary Subject to Combined Bending Moment and Water Pressure

“…Furthermore, to ensure that cast-in-place reinforced concrete underground silos are more sustainable [39][40][41][42][43]-that is, have better waterproof and moisture-proof performance and provide better protection for grain storage, as examined in this study [44][45][46][47]-it is necessary to carry out waterproof research on concrete structures [48][49][50]. Apay et al [51] investigated the influence of waterproof and water-repellent admixtures on the permeability and compressive strength of concrete.…”

Data‐driven identification and modeling of earthquake‐excited building structures regarding soil‐structure interaction

“…The modal characteristics of the global soil‐superstructure system have been changed. [ 1 ] The fundamental period and damping ratio may noticeably and accordingly increase because of the flexibility of the soil and the energy dissipated through the soil, respectively. [ 2 ] A threshold period exists above which the high‐frequency component dominates the structural response.…”