In the present paper, passive control technique such as base isolation system is studied under earthquake ground motions and underground blast-induced vibrations. The performance of the lead rubber bearing (LRB), idealized as Bouc–Wen model in mitigating the structural responses of a five-storey building model, is investigated. The earthquake ground motions are selected from ground motion database available on the portal COSMOS Virtual Data Centre, whereas the underground blast is modeled as an exponential decaying function as prescribed by Carvalho and Battista (Proc Inst Civ Eng Struct Build 156(3):243–253, 2003). The aim of the study is to analyze the effect of isolation parameters such as damping ratio, yield strength, post-yield stiffness ratio and yield displacement on the structural responses of the base-isolated building. Newmark’s step-by-step integration method is adopted to evaluate the structural responses of the building. It is observed that the LRB is very effective in reducing the structural accelerations and storey drifts induced in the building due to ground-induced vibration. The comparison of results show that high value of yield strength harvests low bearing displacement and low percentage reduction in the top floor absolute acceleration. In addition, the study also evaluates the energy dissipated by the isolated structure. The energy dissipated by the base-isolated (LRB) building subjected to blast-induced vibrations, show that an optimum value of yield strength is found to be in the range of 10–20% of the total weight of the structure.

Sunil Sudhakar Pimplikar

School of Civil Engineering

Engineering and Technology

Mohd Zain Kangda

Sachin Bakre

MIT-World Peace University (MIT-WPU) is a top educational institute located in Pune, India. It is recognized within&nbsp;UGC under Government of Maharashtra Act No. XXXV 2017.&nbsp;

It is part of the MIT group of institutions (established in 1983) which covers 10+ campuses across India and has more than 50,000+ students enrolled across various disciplines at a given point of time. The institute houses 15 schools ranging from Engineering &amp; Technology, Design, Pharmacy, Commerce, Governance among others. It offers undergraduate, postgraduate and PhD programs among different disciplines.&nbsp;

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MIT World Peace University

Arab J Sci Eng

The response reduction efficiency of passive control viscous dampers installed between adjacent structures subjected to blast-induced vibrations was investigated. The blast-induced vibrations studied were mainly due to mining activities along with the accidental explosions in underground storage chambers. Equations of motion formulated by different researchers in examining the performance of damper-connected structures were reviewed. Two different types of structures (similar and dissimilar buildings) were selected to analyse the effectiveness of damper-connected buildings. A parametric study was also conducted to determine the optimum damper placement locations along with optimum damper properties for the similar buildings connected with viscous dampers. The results showed the efficiency of viscous dampers for the case of similar buildings. For dissimilar buildings, the peak responses were found to be almost equivalent for both connected and unconnected structures. Therefore, the root mean square responses were evaluated to compare the effect of blast vibrations beyond the initial impulse for the case of connected dissimilar buildings. In addition, the performance of similar structures connected with the same damping was compared with the responses obtained from different damping conditions to minimise the damping coefficient of dampers.

Proceedings of the Institution of Civil Engineers-Structures and Buildings

Response control of adjacent structuressubjected to blast-induced vibrations

The last few decades have shown a dramatic increase in the number of man-made disaster activities resulting in extensive life loss and structural failures. The explosive devices used in these heinous acts result in blast wave loading. Therefore, the present structural engineers require comprehensive expertise to analyze and design blast-resistant structures. The present study aims to develop blast load time history based on the previous research works and demonstrates the effectiveness of base isolation technique such as lead rubber bearings in mitigating the structural responses under the effect of blast loading. Two base-isolated building models systems are analyzed to examine the role of structural control strategies subjected to blast loading. Various isolation parameters are also incorporated in the present investigation in improving the structural performance subjected to this extreme dynamic loading. The study concludes that base isolation is an efficient technique in reducing structural output parameters such as peak storey displacement, storey drift and root mean square absolute acceleration values due to post-blast effects. Energy-based equations are also examined in the study to evaluate the hysteretic energy dissipated by the system subjected to blast loading.

Arabian Journal for Science and Engineering

Positive-Phase Blast Effects on Base-Isolated Structures

In this investigation, the equivalent linear elastic-viscous model of shape memory alloy (SMA) is established for seismic analysis of base-isolated structures using system identification method. The necessary key parameters to express the hysteresis loop of SMA are austenite stiffness, transformation strength, ductility ratio, and stiffness ratio. These parameters are considered in the modeling. This model is developed based on the American Association of State Highway and Transportation Officials (AASHTO) isolation guidelines. In order to validate the proposed model, the base-isolated benchmark building is analyzed by using proposed equivalent linear SMA model as well as the different non-linear SMA models. The evaluation criteria given in the benchmark problem and time variation of top-floor absolute accelerations and base-displacements are considered for comparing the linear and nonlinear models of SMA. An excellent agreement is achieved between proposed equivalent linear SMA model and its nonlinear models. The seismic code recommends that the equivalent linear model of the nonlinear system can be used for carry out the response spectrum analysis of base-isolated structures. Furthermore, the non-linear model requires computationally more time and effort, especially for larger degrees of freedom system. The proposed model may be useful to design engineers in order to over come the disadvantage of non-linear models. © 2016 Elsevier Ltd. All rights reserved.

Advances in Engineering Software

Equivalent linear elastic-viscous model of shape memory alloy for isolated structures

In the recent decades, effects of blast loads on natural and man-made structures have gained considerable attention due to increase in threat from various man-made activities. Site-specific empirical relationships for calculation of blast-induced vibration parameters like peak particle velocity (PPV) and peak particle displacement (PPD) are commonly used for estimation of blast loads in design. However, these relationships are not able to consider the variation in rock parameters and uncertainty of in situ conditions. In this paper, a total of 1089 published blast data of various researchers in different rock sites have been collected and used to propose generalized empirical model for PPV by considering the effects of rock parameters like unit weight, rock quality designation (RQD), geological strength index (GSI), and uniaxial compressive strength (UCS). The proposed PPV model has a good correlation coefficient and hence it can be directly used in prediction of blast-induced vibrations in rocks. Standard errors and coefficient of correlations of the predicted blast-induced vibration parameters are obtained with respect to the observed field data. The proposed empirical model for PPV has also been compared with the empirical models available for blast vibrations predictions given by other researchers and found to be in good agreement with specific cases. © 2016 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences.

Fulltext

Journal of Rock Mechanics and Geotechnical Engineering

Determination of blast-induced ground vibration equations for rocks using mechanical and geological properties

Journal of Engineering Mechanics

Performance and Protection of Base-Isolated Structures under Blast Loading

Journal of Vibration and Control

Performance of N-Z systems in the mitigation of underground blast induced vibration of structures

In the recent past, the topic of blast loads on structures has received considerable attention from researchers. Site-specific empirical models for blast-induced vibration parameters like peak particle velocity (PPV), peak pressure (PP), peak particle displacement (PPD), and pore pressure ratio (PPR) are commonly used for blast-resistant designs. However, these empirical models do not consider the variation in soil properties, e.g., the degree of saturation and uncertain in situ conditions. Hence, in this paper, a total of 120 pieces of blast data from various soil sites have been collected and used to propose a generalized empirical model for estimating blast-induced vibration parameters by considering three basic soil properties, namely, unit weight, degree of saturation, and Young's modulus. Standard errors and coefficients of correlation for the prediction of blast-induced vibration parameters by various empirical models are obtained with respect to the observed soil field data. The present empirical model has been compared with the models of other researchers and found to be in good agreement for specific cases. The present model, having maximum coefficient of correlation and minimum standard error, can be directly used in the calculation of blast loading for design. The present model has also been validated for various degrees of saturation. It has been found that the present model predicts fairly for fully saturated soils irrespective of soil type, and predicts higher values (critical values for design) for partially saturated soils. In the absence of field blast vibration data because of economic, safety, and environmental constraints, the present model will evaluate the blast vibration parameters by using only three basic soil properties. © 2014 American Society of Civil Engineers.

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