Displacement Drift Research Articles

Analysis of Roof Displacement in Steel Structures with and without Panel Zone

The purpose of this study is to determine how panel zones influence the seismic behavior of steel structures in Medan City, utilizing the Indonesian earthquake zone standards SNI 1726:2019 and focused on seismic design category D. The structures are designed with the special moment-resisting frame (SMRF) system, which has a seismic significance factor of 4 and soft soils. The study examines the roof displacement and story drift ratio of a 7-story steel structure with and without panel zones subjected to seismic loads. The results show that the building with panel zones has a roof displacement that is approximately 9.23% higher in the X direction and 10.41% higher in the Y direction than the structure without panel zones. Similarly, the story drift ratio for the structure with panel zones is 9.21% greater in the X direction and 11.55% greater in the Y direction than the structure without panel zones. These findings indicate that incorporating panel zones changes a rigid structure into a semi-rigid one, allowing more rotational movement at the beam-column joints, thereby improving the building's flexibility and overall earthquake resistance.

IMPACT OF SEISMIC ZONES ON THE STRUCTURAL DESIGN OF HIGHRISE BUILDINGS FOR RECTANGULAR AND C-SECTION

Earthquakes induce vibrations in structures, causing motion in horizontal and vertical directions, with horizontal shaking being predominant. Proper consideration of lateral loads due to earthquakes is essential for designing earthquake-resistant reinforced concrete (RC) structures, especially high-rise buildings. This study analysesthe behaviour of a G+15 multi-storied RC building with a consistent story height of 3 meters, subjected to earthquake loads, using response spectrum analysis as per IS 1893 (Part-1): 2016. The seismic performance is evaluated for four seismic zones (II, III, IV, and V) using the ETABS software. Key parameters analysed include bending moment, shear force, lateral displacement, story shear, and story drift. Comparative results highlight the effects of varying seismic zone factors. The findings contribute to understanding structural behaviour under seismic conditions and optimizing designs for enhanced safety and performance in earthquake-prone regions. Keywords: Earthquake-resistant design, Seismic analysis, Response spectrum analysis, Reinforced concrete (RC) buildings, Seismic zones, ETABS, IS 1893 (Part-1): 2016.

A comparative analysis of an RC low-rise building with the seismic codes of countries lying in the Himalayas: China, India, Nepal, and Pakistan

The Himalayan region is one of the most seismically active areas in the world due to its tectonic setting. This vulnerability poses significant risks to buildings, resulting in substantial loss of life, property, and infrastructure. This study investigates the seismic performance of a reinforced concrete (RC) low-rise building using the seismic codes of countries situated along the Himalayan belt: China, India, Nepal, and Pakistan. These countries, despite sharing a common geological seismic threat, have developed a distinct code and standards for construction. This inconsistency concerns the effectiveness and suitability of seismic design practices in this region, hence prompting a comparative study. This study begins by reviewing the development of seismic codes in these countries. Subsequently, a prototype RC low-rise building was modeled and analyzed using finite element software, employing the linear static method of analysis according to each country's seismic codes. This study focused on key seismic responses, including the fundamental period, base shear, displacement, and story drift. The analysis revealed significant differences in seismic responses among the codes. Notably, the Chinese seismic code resulted in the highest values for the parameters studied, followed by the Nepalese, Pakistani, and Indian codes. The comparison revealed that the base shear from the Chinese code was the highest, being 3.10 times greater than the Indian code, 1.66 times greater than the Nepalese code, and 1.86 times greater than the Pakistani code. Similar ratios for displacements and story drifts were found in the study.

Numerical Prediction of Two-Dimensional Coupled Galloping and Vortex-Induced Vibration of Square Cylinders Under Symmetric/Asymmetric Flow Orientations

This study presents an advanced numerical model for predicting a two-dimensional coupled galloping and vortex-induced vibration (VIV) in cross-flow and in-line directions of square cylinders under symmetric and asymmetric flow orientations. The present model combines the quasi-steady theory for the galloping with the nonlinear structure-wake oscillators simulating VIV, capturing the time-varying drag and lift hydrodynamic forces with the time-averaged and fluctuating components. By placing a flexibly mounted square cylinder in uniform flow at an initial angle of incidence, the cylinder is subject to instantaneous changes in the dynamic angle of attack accounting for relative flow-structure velocities. Modelling of such features in cross-flow and in-line directions for low and high mass ratio systems extends previous studies which have mostly focused on cross-flow responses of square cylinders with high mass ratios at a zero angle of incidence. New sets of empirical coefficients governing the drag and lift fluid forces for both the quasi-steady and wake oscillator approaches are introduced by calibrating with available experimental data in the literature, applicable to predict several flow-induced vibration phenomena under arbitrary flow-structure orientations. Mathematical criteria for the onset of two- and one-dimensional galloping instability are presented, verifying the likelihood of galloping occurrence. Parametric investigations are carried out to highlight the important effects of flow incidence angle, mass-damping ratio (Scruton number) and in-line response on the prediction of galloping and VIV in comparison with experimental results. By varying the reduced velocity parameter, the present model captures key qualitative features of the dominant galloping, interfering galloping-VIV and dominant VIV through the response amplitudes, mean drift displacements, oscillation frequencies, fluid force components and motion trajectories. Contributions from in-line responses are found to be meaningful for the interfering galloping-VIV system with a low mass-damping ratio and for an asymmetric flow orientation. The present model could be further calibrated and applied to other fluid-structure interaction applications with non-circular cross-sectional geometries under omnidirectional flow directions.

Seismic analysis of vertically irregular RCC high-rise buildings: A study with provision of FVD at various locations

Abstract Irregular buildings are a significant part of urban infrastructure, often resulting from architectural, functional, and economic constraints. Among these, structures embracing vertical irregularities are predominantly receptive to dynamic loads, with earthquakes being the most damaging event. The dynamic forces acting on a structure during an earthquake generate vibrations and increase the energy within the structure. The primary role of a structure is to withstand these lateral loads and transmit them to the foundation. To enhance the seismic performance of such structures, various energy dissipation systems are employed to absorb and dissipate the released energy, thereby improving the building’s response to earthquake forces. This study focuses on the use of Fluid Viscous Dampers (FVDs) to dissipate energy from the structure. It involves a comparative analysis of effect due to inclusive and non-inclusiveness of fluid viscous dampers at various locations for Set-Back and Step-Back type vertical irregular high-rise buildings. The analysis aims to study key response parameters such as modal time-period, storey displacement, mode type, storey shear, torsional irregularity, and storey drift using ETABS software. The primary objective is to enhance understanding of the seismic behaviour of high-rise reinforced concrete structures with vertical irregularities and Fluid Viscous Dampers (FVDs) at different locations.

A Comparative Study on Seismic Behaviour of Plan Irregular Buildings

Abstract: Asymmetrical plan irregularities occur when the horizontal layout of a building is non uniform or unsymmetrical in one or more axes. These irregularities may arise from variations in building shape, size, or configuration, leading to nonuniform distribution of mass, stiffness, or load paths throughout the structure. Considering equivalent static analysis (ESA) and response spectrum analysis (RSA) as per IS 1893-Part 1 (2016) considering seismic zones III, structure with square shaped plan performs better than the other shaped models (viz. T, L, H and Plus shapes) with least values of storey displacement and storey drift ratio, and also with higher value of storey stiffness. Thus, square plan shaped structure is seismically more resistant than T, L, H and Plus shaped structures.

Review on Fragility Analysis of Building Structure in Seismic Prone Area

In general, using a steel bracing system is the most effective choice for enhancing the resistance of reinforced concrete frames to lateral loads. Steel bracing offers notable advantages over other methods, including greater strength and stiffness, cost-effectiveness, a smaller footprint, and minimal additional weight on existing structures. Both empirical and analytical fragility curves have been taken into account. Strengthening seismically deficient reinforced concrete frames with steel bracing systems is a practical solution for improving earthquake resilience. Nearly all structural analysis software, such as ETABS and SAP2000, supports linear and nonlinear static analysis for high-rise structures. Key parameters include fragility curves, the P-Δ effect, base shear, lateral displacement, axial force, and story drift, among others. The findings showed that bracing systems significantly reduce lateral displacement in frames. Fragility curves were developed based on peak ground acceleration (PGA) for various limit states—slight, moderate, major, and collapse-assuming a lognormal distribution. This study aims to develop analytical fragility curves for high-rise building structures.

Seismic Response of Open Ground Story Reinforced Concrete Buildings, Considering with Soil-Structure Interaction

This study investigates the seismic behavior of open-ground story (OGS) reinforced concrete buildings with soil-structure interaction (SSI) using SAP2000. The study mainly focused on mid-rise (8-storey) and low-rise (4-storey) OGS buildings, incorporating different masonry infill materials such as brick, concrete blocks, and autoclaved aerated concrete (AAC) blocks. Selected ground motions from the Bhuj, El Centro, and Chi-Chi earthquakes were utilized to simulate varying seismic intensities and frequency content. Critical parameters such as top-story displacement and inter-story drift are analyzed to assess the structural safety and serviceability of RC buildings. The results demonstrate that both OGS coupled with SSI and masonry infill type significantly affect the displacement and drift, with mid-rise buildings showing more pronounced impacts. Furthermore, ground motion characteristics are critical in producing different response patterns. The study highlights the importance of considering SSI, infill materials, and ground motion characteristics in the design of OGS buildings to enhance earthquake resilience and reduce seismic damage.

An optimal nonlinear fractional order controller for passive/active base isolation building equipped with friction-tuned mass dampers

This paper presents an optimal nonlinear fractional-order controller (ONFOC) designed to reduce the seismic responses of tall buildings equipped with a base-isolation (BI) system and friction-tuned mass dampers (FTMDs). The parameters for the BI and FTMD systems, as well as their combinations (BI-FTMD and active BI-FTMD or ABI-FTMD), were optimized separately using a multi-objective quantum-inspired seagull optimization algorithm (MOQSOA). The seismic performances of the BI, FTMD, BI-FTMD, and ABI-FTMD systems for a 15-storey building subjected to two far-field (Loma Prieta and Landers) and two near-fields (Tabas and Northridge) earthquakes were evaluated. The results indicated that structures with BI, FTMD, BI-FTMD, and ABI-FTMD systems outperformed the uncontrolled structure in reducing structural responses during the design earthquakes (Loma Prieta and Tabas). However, under validation earthquakes (Landers and Northridge), the peak acceleration of the building with the FTMD system was worse than that of the uncontrolled structure during the near-field Northridge earthquake. To address this issue, we proposed a combination of the active BI system and the FTMD system. Time history analysis results demonstrated that for the building equipped with the ABI-FTMD system, the peak displacement, peak acceleration, and peak inter-storey drift were reduced by approximately 60%, 64%, and 78%, respectively, as compared to the uncontrolled structure.

Effect of Vertical Aspect Ratio on Mass, Stiffness and Vertical Geometric Irregular Structures

Occurrence of earthquake will highly damage the structures which are not modelled and designed to resist such loads it may cause sometimes the collapse of structures leads to loss of human lives. The size of the building and slenderness ratio are the important factors for the efficient structural design. The aspect ratio of buildings is considerably effects under seismic loads. It is important to know the influence of aspect ratio on the irregular structures in high seismic zone areas. The research has been performed on the 15 storey building frames of five cases with mass, stiffness and vertical geometric irregularities. Each case comprises of four models having various vertical aspect ratios. The purpose of this study is to investigate the influence of vertical aspect ratio on mass, stiffness and vertical geometric irregular structures and how the structure will vary under seismic loads. The irregularities are incorporated in to the buildings by increasing the loads and column height in particular storeys and by eliminating the columns and beam sections compared to adjacent storeys. Linear dynamic analysis is performed. It is observed that with the decrease of vertical aspect ratio the structural response will increases the response of storey displacement, base shear, storey drift and over turning moment in the cases of mass and stiffness irregular structures. In the case of vertical geometric irregular structures with the decrease of vertical aspect ratio the storey displacement and storey drift values decrease for all the models, the base shear, overturning moment and stiffness increases with the decrease of vertical aspect ratio. Key words: Mass irregularity, Stiffness irregularity, Vertical geometric irregularity, Vertical aspect ratio, Linear dynamic analysis.

An electronic nose drift compensation algorithm based on semi-supervised adversarial domain adaptive convolutional neural network

Sensor drift is a significant challenge leading to performance degradation in electronic nose(E-nose) systems. Effectively addressing sensor drift represents the most daunting problem in E-nose technology. This work proposes a domain adaptive approach called Semi-Supervised Adversarial Domain Adaptive Convolutional Neural Network (SAD-CNN) to tackle the long-term drift in E-nose and device displacement. SAD-CNN leverages adversarial learning to minimize distribution disparities between the source and target domains. Unlike traditional methods employing projection matrices, SAD-CNN utilizes one-dimensional convolutional neural networks as feature extractors, circumventing the complexities associated with parameter adjustments and matrix calculations in the projection process. During the training process, utilizing pseudo-labels generated by the semi-supervised self-training method to train the model, thereby reducing the labeling costs. Additionally, confidence threshold screening is introduced during the self-training phase to minimize erroneous pseudo-labels. Furthermore, the regenerative Hilbert space’s Maximum Mean Difference combined with Minimum Variance is introduced as a domain constraint function to mitigate distribution discrepancies between domains and enhance feature discriminability across domains. The experimental results demonstrate that the SAD-CNN method outperforms others. Within the long-term drift dataset, the classification accuracies for different scenarios are 78.01 % and 82.53 %, respectively. Meanwhile, the instrument change dataset yields a classification accuracy of 96.45 %.

Unsymmetricity effects on seismic performance of multi-story buildings

The unsymmetrical configurations in buildings lead to non-uniform distributions in their strength, mass, and stiffness, and they are consequently prone to damage during seismic hazards. In this study, the seismic performance of multi-story buildings with 5, 8, 10, and 12 stories of square, ‘L’, ‘T’, and ‘U’-shaped buildings have been investigated. The research deals with the variation of the natural time periods and how it affects the seismic performance of unsymmetrical multi-story buildings. The coupled and uncoupled equations of motion, based on the symmetricity of the buildings about both axes, were solved to obtain natural time periods that influence the spectral acceleration of the ground accelerations. Six important ground accelerations were considered. Nonlinear static analysis, such as pushover analysis, was also carried out on all the buildings. Comparisons were made on the seismic behavior of both the symmetrical and unsymmetrical structures. The results revealed that the spectral acceleration influences dynamic responses, such as base shear, base moment, base torsion, roof displacement, roof rotation, and story drifts of the buildings. Moreover, it was found that even though the ‘L’-shaped buildings are unsymmetrical about both axes, they are less vulnerable than the ‘T’ and ‘U’-shaped buildings, which are unsymmetrical about one axis.

Accelerometer-aided millimeter-wave radar interferometry for uninterrupted bridge displacement estimation considering intermittent radar target occlusion

Monitoring bridge displacement is necessary to detect early signs of damage, prevent catastrophic failures, and maintain public confidence in the safety of critical transportation infrastructure. Radar interferometry is attractive for long-term continuous monitoring of bridge displacements, given its resilience to weather and lighting conditions. However, intermittent radar target occlusions caused by moving vehicles beneath bridges pose challenges during extended continuous monitoring periods. In this study, accelerometer-aided millimeter-wave radar interferometry was explored with an explicit consideration of intermittent radar target occlusion. Radar and accelerometer measurements were first recorded over a short period. Multiple good targets were selected among all radar-detected targets, and their direction-converting factors were estimated using short-period measurements. Subsequently, bridge displacement was continuously estimated by overcoming intermittent radar target occlusions. A displacement reconstruction algorithm was proposed for target occlusion periods, and a multitarget-based phase-unwrapping algorithm was proposed to remove the displacement drift caused by radar target occlusion. The proposed technique was experimentally validated through laboratory tests on a 10-meter-long bridge structure and field tests on two different spans of a footbridge. The technique accurately estimated displacements with overall errors below 0.1 mm, allowing it to be widely applied to bridges with millimeter-scale displacements.

Comparative Seismic Analysis of Regular and Irregular Multistorey Structures with and without Bracings and Shear wall

Abstract Seismic effect is one of the main factors which has to be considered during the design of structure. Earthquake is one of the supreme hazards for living and assets on earth. It is a natural phenomenon, occurring with uncertainties as a result of sudden release of energy within earth crust in the form of seismic waves. As the earthquake forces affects the stability of the building and about 60% of region in our country is under the influence of seismic forces, the buildings are provided with alternatives to withstand the horizontal forces and to increase the strength, stability and stiffness. Present paper investigates the performance of different structures provided with seismic resisting components. In this paper Shear walls and bracings are incorporated to make the structure moment resisting frame. A comparative seismic analysis of high-rise structures with and without shear walls and bracings is included in this discussion which is done using ETABS 2019 software by Response Spectrum Analysis. The parameters considered for analysis are natural frequency, natural time period, base shear, story stiffness, story displacement and story drift. in constructing both.

Influence of Ground Motion Non-Gaussianity on Seismic Performance of Buildings

The non-Gaussian feature of seismic ground motion has been reported in some works. However, there remains a lack of research on the influence of the ground motion non-Gaussianity on the seismic performance of buildings, which motivates this study. By employing a non-Gaussian non-stationary random process simulation method previously proposed by the authors, 40,000 ground motion acceleration signals are efficiently generated, including 20,000 Gaussian and 20,000 non-Gaussian records. As computational examples, a four-story frame building and a three-tower super-tall building are selected. The generated acceleration signals serve as external excitations for the two buildings, allowing for a comparison of the differences in seismic structural responses caused by the Gaussian and non-Gaussian earthquake groups. Probability analysis is performed using top-layer displacement and maximum inter-story drift ratio as damage indicators. The results show that the structural responses induced by both Gaussian and non-Gaussian earthquake groups have identical first- and second-order moments but different higher-order moments. The responses from non-Gaussian earthquakes display distinct non-Gaussian traits, with their distribution of extreme values exhibiting a longer tail compared to the Gaussian counterparts. This leads to a notably larger value of non-Gaussian responses under high crossing probabilities, with an amplification that can surpass 18%.

Comparison of Seismic Performance of Buildings with Conventional Slab and Flat Slab in Different Zones of Bangladesh

As usable land is scarce in Bangladesh, the demand for high-rise buildings has risen over the past few decades. Conventionally, reinforced cement concrete (RCC) structures in Bangladesh have been used for residential, educational, institutional & commercial purposes. Bangladesh is located in a relatively earthquake-prone region on the fault plane; it is of utmost importance to assess seismic conditions while constructing a structure. Three types of slabs have been analyzed: conventional RCC slab, flat slab with drop panel, and flat slab with drop panel & shear wall. Typically, a conventional RCC slab contains a beam, column & slab with a large thickness of the beam. To avoid this, a flat slab with a drop panel may be used, but it has some limitations. As it has no lateral support, a flat slab with a shear wall can be replaced to gain more stability. According to BNBC 2006, Bangladesh was divided into three seismic zones. However, according to BNBC 2020, it is revised into four seismic zones. Seismic comparisons of three models in four seismic zones have been conducted. Maximum story displacement, maximum story drift, overturning moment and story shear have been found after analyzing three different types of models located in different seismic zones. The maximum story displacement and maximum story drift for flat slabs are greater than conventional slabs and flat slabs with shear walls. Moreover, the displacement between conventional and flat slabs with shear walls varies a little. Maximum overturning moment and story shear: it appears that for the traditional slab, the value is maximum, the flat slab is minimum, and the flat slab with the shear wall is between those two. The model for flat slab has been found to be more flexible than conventional RCC slab and flat slab with the shear wall.

Dynamic Response of Steel Structure with Bracings and Translational Tuned Mass Dampers

In this work the dynamic response of steel structure with Bracings and Translational Tuned Mass Damper (TTMD) are studied. TTMD is a device that consists of a mass which is connected to the structure by means of a spring and a damper. The mass is tuned to vibrate at the different frequency as the structure, which allows it to cancel out the vibrations of the structure. Bracings are added to the structure to provide additional stiffness and strength. G+5, G+15 and G+25 Storeyed steel structure models with the different combinations of bracings and TTMD are considered in this study. Following which the FE Analysis involving the modal, equivalent static and response spectrum analysis are performed and results are obtained in terms of Time period, Base Shear, storey displacement and Storey drift all are discussed.

Effects of Soft Story Locations on the Nonlinear Time History Analysis of Multistory Reinforced Concrete Buildings

Abstract The current paper included studying the effects of soft storey locations on dynamic response of reinforced concrete (RC) buildings under the impacts of earthquakes. Soft storey is essential to provide the building with a functional space such as vehicle garages or open meeting rooms. Further analytical investigation was necessary to understand the impact of these flexible floors on the building's response during earthquakes, as conducting experimental research to address this issue is highly difficult. The research encompassed the effects of soft storey location in two types of buildings, one with equal spans and the other with unequal spans, on the nonlinear time history response. Each building consists of a 10-stories (G+9) RC residential structure subjected to earthquake effects. The analysis was carried out using program sap2000 v23. An analogous diagonal strut was used to illustrate the infill panels. The study included the effect of soft storeys on the natural period, the change in base shear with time, and the change of displacement and acceleration along time for each building. The obtained results showed that including a soft storey in the analysis for buildings having either equal or unequal spans increased the time period, displacement, and storey drift, causing a decrease in the acceleration and base shear forces. Building with the soft storey on the fifth floor (at the mid-height of the building) showed a better dynamic response compared with that using the soft storey on the ground and last floors.

Comparative Study of RCC Structure of different types by using Shear Wall, Damper & Bracing System

In seismically active places, earthquake restrictions would provide a difficulty to the majority of multistory buildings. The fundamental issue in the design of the multi-story building is lateral stability, which is required to control lateral drift and displacement, withstand lateral pressures, and avoid buckling. Reinforced concrete (RCC) structures usually utilise a damper, bracing, and shear wall system to mitigate the impacts of seismic activity. Both systems have significant structural performance. Despite the fact that both technologies are used for the same purposes, their effects and behaviour in response to seismic load differ. The G+12 storey building, shear wall and bracings will all be considered in this project's analysis. The following criteria will be used to evaluate the building's performance: base shear, storey displacement, and storey drift. This research includes dampers, shear walls, and bracings at various places, and the Etabs 2018 programme will be utilised for the entire analysis.

Seismic performance of BRBF with SMA core using incremental dynamic analysis

ABSTRACT In this paper, a new model for Buckling Restrained Braced Frames (BRBF) is proposed that Shape Memory Alloy (SMA) is used for the yielding core instead of steel. The seismic behaviour of a framed structure with chevron type buckling restrained braces is investigated and their seismic performance factors, such as permanent displacements, inter story drifts and response modification factors are evaluated. Nonlinear time history analysis and Incremental Dynamic Analysis (IDA) of two models subjected to 11 ground motion records is performed using OpenSees software. In order to evaluate the efficiency of the proposed model, it is compared to a BRB model with a steel core that the length of yielding core is 1 m for each model. Comparing the proposed bracing systems with conventional BRBFs indicates that buckling restrained braced frames equipped with SMA are better in terms of permanent roof displacement and maximum inter-story drift. However, the response modification factor of BRB models with steel core is higher.