Integrated design of hybrid interstory-interbuilding multi-actuation schemes for vibration control of adjacent buildings under seismic excitations

The design of vibration control systems for the seismic protection of closely adjacent buildings is a complex and challenging problem. In this paper, we consider distributed multi-actuation schemes that combine interbuilding linking elements and interstory actuation devices. Using an advanced static output-feedback H∞ approach, active and passive vibration control systems are designed for a multi-story two-building structure equipped with a selected set of linked and unlinked actuation schemes. To validate the effectiveness of the obtained controllers, the corresponding frequency responses are investigated and a proper set of numerical simulations is conducted using the full scale North–South El Centro 1940 seismic record as ground acceleration disturbance. The observed results indicate that using combined interstory-interbuilding multi-actuation schemes is an effective means of mitigating the vibrational response of the individual buildings and, simultaneously, reducing the risk of interbuilding pounding. These results also point out that passive control systems with high-performance characteristics can be designed using damping elements.Peer ReviewedPostprint (published version

Effect of reconstituted method on shear strength properties of peat

Peat is an organic soil contains more than 75% organic content. Shear strength of the soil is one of the most important parameters in engineering design, especially during the pre-construction and post-construction periods, since used to evaluate the foundation and slope stability of soil. Peat normally known as a soil that has very low shear strength and to determine and understand the shear strength of the peat is difficult in geotechnical engineering because of a few factors such as the origin of the soil, water content, organic matter and the degree of humification. The aim of this study was to determine the effective undrained shear strength properties of reconstituted peat. All the reconstituted peat samples were of the size that passing opening sieve 0.425mm, 1.000mm, 2.360mm and 3.350mm and were preconsolidated at pressures of 50 kPa, 80 kPa and 100 kPa. The relationship deviator stress- strain, σdmax and excess pore water pressure, Δu, shows that in both of reconstituted and undisturbed peat gradually increased when confining pressure, σ’ and pre- consolidation pressure, σc increased. As a conclusion, the undrained shear strength properties result obtained shows that the RS3.350 has higher strength than RS0.425, RS1.000 and RS2.360. However, the entire reconstituted peat sample shows the increment value of the shear strength with the increment of peat size and pre- consolidation pressure. For comparison purposes, the undrained shear strength properties result obtained shows that the reconstituted peat has higher strength than undisturbed peat. The factors that contributed to the higher shear strength properties in this study are segregation of peat size, pre- consolidation pressure, initial void ratio and also the physical properties such as initial water content, fiber content and liquid limit

Computational effectiveness of LMI design strategies for vibration control of large structures

Distributed control systems for vibration control of large structures involve a large number of actuation devices and sensors that work coordinately to produce the desired control actions. Design strategies based on linear matrix inequality (LMI) formulations allow obtaining controllers for these complex control problems, which are characterized by large dimensionality, high computational cost and severe information constraints. In this paper, we conduct a comparative study of the computational effectiveness of three different LMI-based controller design strategies: H-infinity, energy-to-peak and energy-to-componentwise-peak. The H-infinity approach is a well-known design methodology and has been widely used in the literature. The energy-to-peak approach is a particular case of generalized H2 design that is gaining a growing relevance in structural vibration control. Finally, the energy-to-componentwise-peak approach is a less common case of generalized H2 design that produces promising results among the three considered approaches. These controller design strategies are applied to synthesize active state-feedback controllers for the seismic protection of a five-story building and a twenty-story building both equipped with complete systems of interstory actuation devices. To evaluate the computational effectiveness of the proposed LMI design methodologies, the corresponding computation times are compared and a suitable set of numerical simulations is carried out to assess the performance of the obtained controllers. As positive results, two main facts can be highlighted: the computational effectiveness of the energy-to-peak control design strategy and the particularly well-balanced behavior exhibited by the energy-to-componentwise-peak controllers. On the negative side, it has to be mentioned the computational inefficiency of the considered LMI design methodologies to properly deal with very-large-scale control problems.Peer ReviewedPostprint (published version

Pole Assignment With Improved Control Performance by Means of Periodic Feedback

This technical note is concerned with the pole placement of continuous-time linear time-invariant (LTI) systems by means of LQ suboptimal periodic feedback. It is well-known that there exist infinitely many generalized sampled-data hold functions (GSHF) for any controllable LTI system to place the modes of its discrete-time equivalent model at prescribed locations. Among all such GSHFs, this technical note aims to find the one which also minimizes a given LQ performance index. To this end, the GSHF being sought is written as the sum of a particular GSHF and a homogeneous one. The particular GSHF can be readily obtained using the conventional pole-placement techniques. The homogeneous GSHF, on the other hand, is expressed as a linear combination of a finite number of functions such as polynomials, sinusoidals, etc. The problem of finding the optimal coefficients of this linear combination is then formulated as a linear matrix inequality (LMI) optimization. The procedure is illustrated by a numerical example

LMI-based design of distributed energy-dissipation systems for vibration control of large multi-story structures

In this paper, we present an advanced computational procedure that allows obtaining distributed energy-dissipation systems for large multi-story structures. The proposed methodology is based on a decentralized velocity-feedback energy-to-componentwise-peak (ECWP) controller design approach and can be formulated as a linear matrix inequality (LMI) optimization problem with structure constraints. To demonstrate the effectiveness of the proposed design methodology, a passive damping system is computed for the seismic protection of a 20-story building equipped with a complete set of interstory viscous dampers. The high-performance characteristics of the obtained passive ECWP control system are clearly evidenced by the numerical simulation results. Also, the computational effectiveness of the proposed design procedure is confirmed by the low computation time of the associated LMI optimization problem.Peer ReviewedPostprint (published version