Overlapping Decentralized Control Strategies of Building Structure Vibration Based on Fault-Tolerant Control under Seismic Excitation

The vibration control system of a building structure under a strong earthquake can be regarded as a large complex system composed of a series of overlapping subsystems. In this paper, the overlapping decentralized control of building structure vibration under seismic excitation is studied. Combining the overlapping decentralized control method, H∞ control algorithm, and passive fault-tolerant control method, a passive fault-tolerant overlapping decentralized control method based on the H∞ control algorithm is proposed. In this paper, the design of robust H∞ finite frequency passive fault-tolerant static output feedback controller for each subsystem is studied. The fault matrix of the subcontroller is expressed by a polyhedron with finite vertices. In order to reduce the influence of external disturbance on the controlled output, the finite frequency H∞ control is adopted and the Hamiltonian matrix is avoided. In this paper, the passive fault-tolerant overlapping decentralized control method based on H∞ control algorithm is applied to the vibration control system of the four-story building structure excited by the Hachinohe seismic wave. One drive is set on each layer of the structure, and a total of four drives are set. Select the driver fault factor of 0.5 or 1 and the frequency band [0.3, 8] Hz. The overlapping decentralized control scheme and 16 fault-tolerant fault matrices are designed, and the numerical comparison results are given. The results show that both overlapping decentralized control strategy and multioverlapping decentralized control strategy have achieved good control results. Due to the different number of subsystems and overlapping information, the overlapping decentralized control scheme increases the flexibility of controller setting and reduces the computational cost.

Thermal Stratification in a Pool with Submerged Heater Under Low Frequency Excitation

Thermal stratification has potential applications in the nuclear and solar industries. Thermal performance of passive residual heat removal systems and solar heaters is affected by the thermal stratification in a pool. Under the seismic condition, thermal stratification behavior of liquid in the pool has never been studied and reported in the literature. The present work focuses on the experimental investigation of thermal stratification in a pool under the seismic condition with the horizontally mounted heater simulating heat exchanger. Effect of heater submergence depth, frequency of excitation and amplitude of displacement on the thermal stratification has been studied. It was observed that the heater submergence depth significantly influences the thermal stratification in a pool. When a pool is subjected to an external excitation, the pool water separates into two zones; convective and impulsive. If the heater submergence depth in the impulsive zone, excitation effects are not found. If heater submergence depth is close to convective zone, significant effects are observed. However, it was observed that only first mode of excitation with large amplitude helps to achieve complete thermal mixing and higher modes of excitation have the minimal on the mitigating of thermal stratification. Non-dimensional stratification number has been evaluated to explain the mitigation of thermal stratification with seismic excitation.

Performance of Building with Basements Under Seismic Excitation Considering Soil Structure Interaction

In modern construction, there is a trend to go deeper below the grade level in terms of basements which can be utilized for parking, shopping malls or a combination of both. In such cases, dynamic soil properties have a significant effect of activating dynamic soil structure interaction phenomenon during earthquake. Here in present study an effort is made to study the behavior of a building by varying five and three number of basements considering dynamic soil structure interaction. Issues like influence zone to be considered for dynamic soil structure interaction, behavior of building with basements under different water level conditions for two different types of layered soil and their comparison with fixed based structure for a real-life structure is dealt with. It is observed that dynamic soil structure interaction can significantly change the behavior and also the failure pattern of the building and hence it is recommended to perform dynamic soil structure interaction for building with multiple basements.

Controlling Seismic Excitation in the RCC Building with a Tuned Mass Damper

The use of multiple tuned mass dampers (MTMDs) to monitor earthquake response of tall buildings is investigated. The MTMDs are located in three locations in the reinforced concrete (RC) structures. The time domain seismic analysis is performed on Etabs Software using imperial Earth movement used to analyze contemporary history. The performance of the MTMDs is compared to that of a TMD on the top floor, a TMD on the third and fifth floors, a TMD on each floor, and no TMD. The base shear vs time and displacement parameters were examined, and it was determined that the MTMDs on each floor are better for the building’s seismic response. Furthermore, it has been discovered that MTMDs are more powerful than STMDs.

Dynamic Response Analysis of a Multiple Square Loops-String Dome under Seismic Excitation

The interaction between multiple loops and string cables complicates the dynamic response of triple square loops-string dome structures under seismic excitation. The internal connection between the multiple square loops-string cables and the grid beams was studies to provide a favorable reference for an anti-seismic structure. With a finite element model of the Fuzhou Strait Olympic Sports Center Gymnasium, established by SAP2000 software, the structural dynamic characteristic parameters were obtained first, and then this study adopted a time-history analysis method to study the internal force response of the cables and the roof grid beams of the multiple square loops-string dome (MSLSD) under three types of seismic array excitation. The influence of two factors, namely the seismic pulse and the near and far seismic fields, on the dynamic response of this structure was analyzed by three groups of different types of seismic excitation (PNF, NNF, PFF). As shown from the results, the first three-order vibration modes were torsional deformations caused by cables, the last five were mainly the overall roof plane vibration and antisymmetric vibration. Under the excitation of the three seismic arrays, the internal force responses of stay cables, square cables in the outer ring and the string cables were largest, while the maximum internal force response of the struts changed with the direction of seismic excitation. The largest internal force response of the roof grid beams occurred in local components such as BX3, BX7 and BY7, and the largest deformation of the beam nodes occurred in JX7, JX12 and JY4. In general, the seismic pulse and the near seismic field weakened the internal force response of the struts and cables but increased the internal force response and deformation of the dome beams, while the near and far seismic fields outweighed the seismic pulse. All the above provides an important reference for structural monitoring and seismic resistance.