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In India, hilly region especially northern part is more seismically active region. Flat Slab systems are widely popular in multi-storey buildings. Flat slab building has more advantages than a regular building like fast construction, free design space, reduced floor to floor height and economical. Flat slab buildings are also being built in high seismicity region. Buildings on hilly ground are vulnerable due to their vertical and horizontal irregularity and they undergo high shear and torsion during the earthquake. Further due to short column and soft storey on uphill side has higher lateral forces that are cause to failure of buildings. In this paper, an attempt has been made to assess the seismic behavior of flat slab resting on hilly slope with soft storey and set back configuration. The methodologies have been adopted are linear dynamic analysis i.e. response spectrum analysis. Building is analyzed and designed by Etabs software. Maximum displacement, maximum inter-storey drift and storey shear are determined as response quantities. It is observed from the study that for flat slab buildings on hill slopes the storey shear is very high in the bottom columns at higher ground level, therefore extra care should be taken to design these columns for earthquake load.

The performance of a three-span integrated bridge is evaluated and compared with a conventional bridge for unidirectional and bi-directional excitation. The conventional bridge deck is connected to abutment through elastomers and the pinned connection is assumed at pier location. The height of the piers is 9.5 m, and the central and end spans are 38.0 m and 15.5 m respectively. A nonlinear time history analysis of the bridge is performed by using CSI Bridge software, for unidirectional and bi-directional excitation. The responses of the integrated bridge are compared with those of the conventional bridge in which bearings are provided between the deck and the support. The parameters varied are the major direction of the application of earthquake time history and PGA. The response quantities of interest include the maximum base shear of piers, maximum stresses developed at the critical sections of the deck, maximum deck deflection at the mid-span, and at the pier supports. The results of the numerical study show that as compared to the conventional bridge the integrated bridge has less base shear but has more stresses in the deck near pier supports; however, the stresses developed at the mid-span of the deck are significantly reduced.

Because of the inherent uncertainty in the blast loading caused due to terrorist attacks, most buildings are not designed for blast loading, but they are routinely designed for earthquake demand. If the blast resistance capacity of the seismically designed building can be evaluated, the risk of the blast loading caused due to the terrorist attacks can be reduced by upgrading the seismic design of the building. With this background in view, the present paper investigates the blast resistance capacity of a 6 storey building frame designed for extreme peak ground acceleration (PGA) levels of 0.5g, 0.4g, and 0.3g. The 3D model of the 6 storey building is designed according to Indian Standard (IS) codes for the above mentioned extreme level earthquake. Designed buildings are subjected to surface blast of 500 kg of TNT(trinitrotoluene) at different standoff distances ranging from 5m to 30m. The time histories of the blast loading due to air pressure and ground shock are modeled by those existing literature. A nonlinear time history of analysis (NTHA) of the frame is performed in SAP 2000 for surface blast and the simulated earthquakes from the specified response spectrum in IS code. NTHA results for both cases are compared to evaluate the relative performance of the three different seismically designed buildings to the surface blast loading. The response quantities of interest include maximum drift, maximum top displacement, and number of hinges formed. The results of the study indicate that for the near blast conditions the blast resistance capacity of the building increases with the increase in the PGA values for which the building is designed. By upgrading the seismic design by 0.1g, the blast resistance capacity increases manifold for near blast conditions. Thus, by updating the seismic design of a building, the risk of blast loading in the design may be considerably mitigated.

The secondary piping systems running along the height of buildings are subjected to significant stresses and accelerations due to the earthquake. Extensive research on the seismic response of primary and secondary systems has been carried out in the past. State of the art review papers on the subjects summarizes those researches. Although the response of the secondary piping system running along with the height of the primary structure like the building has been studied before, the stresses and accelerations developed in the piping system developed due to the bi-directional earthquake are not widely studied. In this paper, a six storied building with a secondary system taken as a pipe running from 1st to 6th story on one side of the building is taken as an illustrative example. A 3-D model of the primary and secondary system is analyzed for bi-directional earthquakes. Considering the full interaction between the primary and secondary structures, the non- linear time history analysis is carried out in SAP 2000 to obtain different response quantities of interest for a PGA level 0.3g with the major to minor ground motion ratio taken as 1:2/3. Response quantities of interest include the maximum accelerations, maximum displacements, and maximum stresses developed at critical sections of the pipe. Also, the floor response spectra are obtained. Results of the numerical study indicate that significant accelerations and stresses are induced in the pipe for a PGA level of 0.3g; the absolute accelerations at the pipe supports vary significantly leading to the generation of large stresses in the pipe.

The seismic design codes consider only single earthquake events, ignoring the possibility of multiple earthquakes. In case a structure suffers damage during first event and prior to its repair more aftershocks occur the structure may collapse. An elaborative directive study on the inelastic seismic response of 11storey RC (2-D) moment-resisting frame having mass irregularity at sixth floor, and stiffness irregularity in sixth story has been done has been done. The frame has been examined under a sequence of a main shock followed by six aftershocks. Time history synthetically generated from the design response spectrum explained in IS-1893 Pt II: 2016 has been taken for non linear dynamic analysis with the help of SAP 2000 software. A comparison is done to understand the inelastic response of the frame taking into account the location of plastic hinges, maximum top displacement, residual top displacement, and storey drift. It is seen that the structure with the stiffness irregularity is the most vulnerable amongst all.

Assessment of the seismic performance of steel structures is topical research for a variety of earthquakes. Moment-resisting rigid steel frames are generally designed and used for high seismic zones. However, the famous Northridge in 1994 and Kobe in 1995 earthquakes exposed the shortcomings of moment frames. During these events, the beam-column connections of rigid moment frames were severely damaged. Since then, an alternative of welded connections called bolted or semi-rigid connections is considered for designing or retrofitting of steel moment frames. From the last few years, the semi-rigid connections combined with rigid connections, termed as hybrid or dual frames have become widely popular for earthquake designers and engineers due to enhanced ductility and reduced cost of construction. Earlier research work was focused on far-field (FF) earthquakes, whereas, the near-field (NF) earthquakes are crucial for civil engineering structures. In this paper, an extensive numerical study is carried on rigid and hybrid steel moment frames for NF and FF earthquakes. For this purpose, a ten-story rigid steel frame is analyzed and designed for seismic requirements as per Indian Standards. The rigid connections of frames are replaced by semi-rigid connections with a moderate degree of semi-rigidity. The six different patterns (locations of semi-rigid connections) of hybrid frames are considered here to compare the seismic performance of hybrid frames under near field earthquakes. The nonlinear response-history analyses are executed using the SAP2000 software at two scaled PGAs defined as low (i.e., 0.2g) and high (0.5g) level. An ensemble of three time-histories, each for both types of earthquakes are considered for the numerical simulation. Response quantities of interest, namely, the maximum value of base shear, story displacement, inter-story drift ratio, the total number of plastic hinges, and the square root of the sum of squares of maximum plastic hinge rotations are considered for the decision of a most appropriate pattern for hybrid frames. The results of the numerical study indicate that the response behavior for the NF earthquakes is distinctly different both in nature and magnitude. It is observed that the seismic demands under the NF earthquakes are substantially more as compared to those obtained for FF earthquakes for all cases of hybrid frames. Further, it is also found that the pattern and number of semi-rigid connections in the hybrid frame have a vital role in seismic performance.

The 1994 Northridge and 1995 Kobe earthquakes have shown the susceptibility of severe damage of welded moment-resisting frames, especially at the beam to column connections subjected to severe earthquake ground-motions. Since then, an alternative of welded connections called bolted or semi-rigid connections is considered for designing or retrofitting of steel moment frames. From the last few years, the semi-rigid connections combined with rigid connections, termed as hybrid frames have become a promising approach to design the steel frames for enhanced seismic performance. In the present paper, a numerical study is carried out to investigate the seismic performance of the hybrid steel frames. For this purpose, a ten-story high-rise rigid steel frame is analyzed and designed for seismic requirements as per Indian Standards. The rigid connections of frames are replaced by semi-rigid connections with a moderate degree of semi-rigidity. The six different patterns (locations of semi-rigid connections) of hybrid frames are considered here to compare the seismic responses with those obtained from the rigid connected steel frame. The nonlinear time-history analyses are executed using the SAP2000 software at two scaled PGA level in compliance with design basis earthquake and maximum considered earthquake. An ensemble of five time-histories of far-field earthquakes is considered for the numerical study. A wide range of seismic response parameters, namely, the maximum value of base shear, top-story displacement, inter-story drift ratio, the total number of plastic hinges is extracted for the suggestion of a suitable pattern for hybrid frames. The major findings from the present numerical study show that the pattern and number of semi-rigid connections in the hybrid frame considerably affect the seismic performance of steel frames. It is also observed from the seismic responses that the hybrid frames are better than the rigid frame at high PGA levels.

A new control algorithm called velocity tracking control (VTC) is presented for the semi-active control of partially observed building frames using magneto-rheological (MR) dampers. The novelty of the control algorithm relies on the use of special features of the semi active control using MR dampers in which the time history of voltage to be applied to the MR damper can be generated with the help of feedback information from the observed states only; it does not require the estimation of the full state from the measured ones which introduces some errors in the estimated control force generated in the MR damper. The algorithm is developed based on a physical reasoning, which is validated by the Lyapunov stability condition of the first order filter used in the modified Bouc-wen model that models the MR damper. The efficiency of the control algorithm is compared with the passive on control for a number of earthquakes. The response quantities of interest, for which percentage reductions in responses are compared, include the peak top floor displacement, peak inter-story drift and maximum base shear. The results of the study show that the proposed control algorithm provides the maximum percentage reduction in peak inter-story drift in comparison to passive on control. Further, the efficiency of the proposed control algorithm, defined by the percentage reduction of responses per unit control force, is found to be more as compared to the passive on control.

Nanotechnology applications are increasingly recognized as potential tools in animal sciences, veterinary medicine, drug delivery, disease diagnosis and vaccine development. The nanoparticles and their therapeutic trends provide a realistic glimpse of current and future trends in veterinary diagnosis and medicine. Nanotechnology is ascribed to provide new horizons for applications in molecular biology and biotechnology by revolutionizing almost every field of veterinary or animal sciences by offering novel nano-scale tools and materials which can benefit society in all walks of life. The nanoparticles have been employed in diverse biological and non-biological functions. Nanomaterials can contribute to the farm animals for long-term sustainability by increasing the quality and quantity of safe, healthy and functional animal products. Although there are advantages while using nanoparticles to enhance performance and heal diseases in livestock, it is universally recognized that some nanoparticles can cause toxic and adverse effects on living creatures. Apart from that, the promise of nanoscience in veterinary medicine and livestock reproduction is yet to be explored. A few studies have been made on the uses of nanoparticles in veterinary medicine, livestock health and reproduction. Awareness is needed about the possible toxic effects and hazards, which could harm the living world. To improve the efficient and accurate diagnosis and treatment of animal diseases, more sophisticated research on nanomaterials and nanomedicines is required.

Buildings with asymmetry and various classes of irregularity are found to be a major cause for collapses of structure, property loss, and casualties during earthquakes. Such observations ha...

A fragility analysis of a fan type cable stayed bridge using a probabilistic risk analysis (PRA) procedure is presented to determine its probability of failure under random ground motion. Seismic input to the bridge support is considered to be a band-limited white noise at the bedrock. For the response analysis, the bridge deck is modeled as a beam supported on springs at different points. The stiffnesses of the springs are determined by a separate 2D static analysis of the cable—tower—deck system. A continuum method of analysis using dynamic stiffness is used to determine the dynamic properties of the bridges.The responses of the bridge deck are obtained by the response spectrum method of analysis for multiple-degrees-of-freedom system. The fragility analysis includes uncertainties of responses due to the variation in ground motion, material properties, modeling and method of analysis. Uncertainties of the capacity of the structure are considered, such as ductility factor variation and damage concentration effects. Failure of the bridge is assumed to take place when the bridge deck moment at any section within a supported span reaches the yield value. The probability of failure of the bridge deck is determined by the first order second moment (FOSM) reliability method. A three-span double-plane symmetrical cable stayed bridge is used as an illustrative example. The fragility curves for the bridge deck failure are obtained under a number of parametric variations which include ratio of the components of ground motion, spatial correlation of ground motion, angle of incidence of earthquake, ductility ratio and coefficients of variation of the uncertainty factors. The results of the study show that these factors have considerable effect on the probability of failure of the bridge.

A seismic risk analysis of modified fan type cable stayed bridges is presented using the concept of damage probability matrix. The cable stayed bridge is modeled as a two dimensional system with the deck idealized as a continuous beam subjected to bending action and axial compression. The response of the bridge is obtained by the frequency domain spectral analysis. A double filtered power spectral density function with seismic intensity parameter taken as the magnitude of an earthquake and a correlation function between the support excitations are considered as seismic inputs. For a given magnitude of earthquake, the damage probability matrix is determined by defining three damage states namely, major, moderate and minor. The seismic risk index is determined by combining the damage probability matrix with the probability of occurrence of different magnitudes of earthquake. As an illustrative example, a three span modified fan type cable stayed bridge is analyzed for an extensive parametric study. The parameters include degree of correlation, angle of incidence of earthquake, ratio of the components of ground motion, and soil condition. Some of the important conclusions of the study indicate that (i) the longitudinal component of ground motion has a considerable effect on the annual probabilities of failure of the bridge deck; (ii) annual probabilities of failure are significantly more for soft soil condition; (iii) fully correlated ground motion between support excitation provides less value of the damage indices as compared to the uncorrelated ground motion; and (iv) annual probabilities of failure are not very sensitive to the variation of angle of incidence of an earthquake.

A simplified fragility analysis of fan type cable stayed bridges using Probabilistic Risk Analysis (PRA) procedure is presented for determining their failure probability under random ground motion. Seismic input to the bridge support is considered to be a risk consistent response spectrum which is obtained from a separate analysis. For the response analysis, the bridge deck is modeles as a beam supported on spring at different points. The stiffnesses of the springs are determined by a separate 2D static analysis of cable-tower-deck system. The analysis provides a coupled stiffness matrix for the spring system. A continuum method of analysis using dynamic stiffness is used to determine the dynamic properties of the bridges. The response of the bridge deck is obtained by the response spectrum method of analysis as applied to multidegree of freedom system which duly takes into account the quasi-static component of bridge deck vibration. The fragility analysis includes uncertainties arising due to the variation in ground motion, material property, modeling, method of analysis, ductility factor and damage concentration effect. Probability of failure of the bridge deck is determined by the First Order Second Moment (FOSM) method of reliability. A three span double plane symmetrical fan type cable stayed bridge of total span 689 m, is used as an illustrative example. The fragility curves for the bridge deck failure are obtained under a number of parametric variations. Some of the important conclusions of the study indicate that (i) not only vertical component but also the horizontal component of ground motion has considerable effect on the probability of failure; (ii) ground motion with no time lag between support excitations provides a smaller probability of failure as compared to ground motion with very large time lag between support excitation; and (iii) probability of failure may considerably increase soft soil condition.

A frequency domain response analysis is presented for building frames passively controlled by viscoelastic dampers, under harmonic ground excitation. Three different models are used to represent the linear dynamic force-deformation characteristics of viscoelastic dampers namely, Kelvin model, Linear hysteretic model and Maxwell model. The frequency domain solution is obtained by (i) an iterative pseudo-force method, which uses undamped mode shapes and frequencies of the system, (ii) an approximate modal strain energy method, which uses an equivalent modal damping of the system in each mode of vibration, and (iii) an exact method which uses complex frequency response function of the system. The responses obtained by three different methods are compared for different combinations of viscoelastic dampers giving rise to both classically and non-classically damped cases. In addition, the effect of the modelling of viscoelastic dampers on the response is investigated for a certain frequency range of interest. The results of the study are useful in appropriate modelling of viscoelastic dampers and in understanding the implication of using modal analysis procedure for building frames which are passively controlled by viscoelastic dampers against base excitation.

A rigorous theoretical investigation has been made of obliquely propagating electrostatic solitary structures in a hot magnetized dusty plasma which consists of a negatively charged, extremely massive, hot, dust fluid and Maxwellian distributed ions and electrons. The reductive perturbation method has been employed to derive the Korteweg–deVries (K–dV) equation which admits a solitary wave solution for small but finite amplitude limit. It has been shown that the effects of dust-temperature, obliqueness, magnetic field and free electrons have changed the nature of the electro-static solitary structures. The result of the present investigation for unmagnetized case, parallel propagation, no free electron and cold dust fluid completely agrees with the existing published results (Mamun et al. [4]).

Numerical analyses on the phenomenon of necking in tensile specimens usually introduce a geometric or deformation defect that initiates flow localization, or treat the onset of necking as a bifurcation in the mathematical solution. These approaches do not, however, appear to be essential in analysing the neck formation. A finite-element analysis without introducing defects or a bifurcation solution is shown in the present paper to be readily responsive to the initiation of necking on fulfilling the critical criterion for neck initiation. In the present FE analysis, the appropriate elements are made to converge to a pre-specified node within the respective elements as an equivalent step to what goes on inside the specimen at the point of incipient necking. The above method is seen to reproduce the usual hour-glass shaped necking profile for an exisymmetric round bar with a shear-free-grip end condition. This work is of industrial significance as the necking profile in tension has an important bearing in determining the ductile behaviour of a material.

A simple method to promote the extraction of copper and iron from chalcopyrite ore using the bacterium Thiobacillus ferrooxidans is reported. The method involves prior treatment of the ore with alkali. The alkali treatment also altered the rate of iron precipitation during the leaching process. An alteration of the microenvironment caused by removal of any inhibitory gangue material is suspected to be the reason for the observed improvement in the leaching rate. The alkali wash method may be a more efficient substitute for “ore regrinding”, the technique suggested by Torma [1] for removal of the inhibitory effect of a passivation layer that prevents further microbial attack onto the ore surface.

The aim of present study is to propose a procedure for reliability analysis using Genetic Algorithm (GA) under seismic loading using Monte Carlo Simulation (MCS). GA is used as a tool for increasing computer efficiency. The procedure is specially referred as Genetic Algorithm Aided Reliability Analysis (GAAR Analysis) to solve problems of structural reliability. Chimney subjected to seismic loading is taken as examples for calculating structural reliability using the GAAR Analysis and comparison is made with conventional MCS method of reliability analysis. The results obtained for realistic structural problem indicates the applicability of the proposed procedure. A computer program is developed in MATLAB for GAAR Analysis.

The response behaviour of flexible marine risers (lazy S type) under lock-in condition during vortex shedding in steady current is investigated. The responses are determined for 2 conditions namely, in-plane and out-of-plane currents. The elastic line of the flexible riser under its own weight is determined by a finite difference method. The dynamic analysis for vortex induced forces is performed by considering the elastic line obtained by finite difference analysis as the mean position of the riser. The transverse oscillations of the riser at lock-in are obtained by a time domain dynamic analysis which duly considers the non-linearity of the reactive forces. During lock-in, the lift force is assumed to be monoharmonic in nature and fully correlated. The parameters used for determining the lift forces are taken from available experimental results on flexible cylinders in uniform flow. In-line response during lock-in is obtained by considering amplified drag coefficients due to variation of the cross sectional modes of oscillation. The results of the study indicate that the dynamic stresses under lock-in condition are quite significant, especially from fatigue point of view. Also, the stresses produced by in-line forces at lock-in are greatly amplified.