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Based on the analysis of the lateral displacement mode and the deformation composition of shear wall structures, the inter-story displacement is divided into physical inter-story displacement and non-physical inter-story displacement. Then, the calculation method of the physical inter-story displacement of a shear wall in the elastic stage and simplified calculation methods in the elastic-plastic stage are given. On this basis, the proportion of the shear and bending deformations of the shear wall structure are analysed using Perform-3D finite element (FE) software. The variation law of the section rotation angle, the inter-story drift ratio, and the physical inter-story drift ratio along the height of the coupled shear wall and wall limb shear wall structure are analysed. Subsequently, a new dual control damage index of the deformation and energy is proposed, and the damage of the structure is evaluated. The results show that the inter-story drift ratio of the shear wall structure should be controlled by the physical inter-story drift ratio, and the shear displacement should not be ignored in the calculation of the inter-story displacement. The proposed dual control damage index of the deformation and energy can better reflect the damage of the structure.

The Conventional buckling restrained braces used in concentrically braced frames are expected to yield in both tension and compression without major degradation of capacity under severe seismic ground motions. One of the weakness points of a standard buckling restrained braced frame is the low post-yield stiffness and thus large residual deformation under moderate to severe ground motions. This phenomenon can be related to the low post-yield stiffness of the core segment in comparison to its elastic stiffness. This paper investigates the application of stainless steel as the core material in a hybrid buckling restrained brace. The “hybrid” term arises from the use of more than one core component with different steel materials, including high strength high-performance steel and stainless steel (304L) with high strain hardening in the core of buckling restrained brace. Nonlinear dynamic time history analyses were conducted on a variety of diagonally braced frames with different heights, in order to compare the seismic performance of standard (non-hybrid) and hybrid buckling restrained braced frames. The results showed that the proposed hybrid buckling restrained braces reduce the inter-story and specially the residual drift demands in buckling restrained braced frames.

This paper presents a comparison of P-Delta effects on the nonlinear seismic behavior of the steel moment-resisting frame structures (MRFs) subjected to near-fault and far-fault ground motions. The 3-, 9- and 20-story MRFs designed for the American SAC Phase II Steel Project are used as benchmark models. The 40 near-fault ground motions with large velocity pulses, as well as ten typical far-fault ground motions, are selected and scaled for the nonlinear time-history analysis. The P-Delta effect is quantified based on peak inter-story drift ratio (PIDR) demands. The displacement demands of the whole structure and the distortion of the structural components are compared and analyzed. It was found that, at each floor, the P-Delta effect under near-fault ground motions is more significant than that under the far-fault ground motions. The P-Delta effect under near-fault ground motions also increases more rapidly with decreasing structure height even for low-rise structures or low earthquake intensity. It was also found that the P-Delta effect cause the PIDR demands to increase by 10% for all three structures subjected to far-fault ground motions. In contrast, considering the P-Delta effect, the PIDR demands rapidly increase by 45% for the high-rise building subjected to near-fault ground motions. Note that the increasing PIDR demands occur at the weakest floor and with the stronger earthquake intensity. However, the P-Delta effect does not change the location of the weakest floor and the yield sequence of components. The seismic behaviors under far-fault and near-fault ground motions are significantly different, because near-fault ground motions not only have velocity pulse but also possibly trigger structural higher vibration modes. In addition, the P-Delta effect may change the distortion direction of the components so that the prediction of the structural collapse direction may be affected. In addition, it was found that if the structure’s period is near the pulse period, the P-Delta effect becomes more significant with the increase of earthquake intensity, and accordingly, it should not be ignored. Moreover, the P-Delta effect cannot be neglected either for the structures susceptible to near-fault ground motions, even if those structures are not tall or the earthquake intensity is not strong.

In modern day, due to the need of unique architectural appearance or aesthetics of building, irregularities in mass, stiffness and symmetry may get disturbed, making the whole structure vulnerable to certain damages either minor or major. Some of the functional considerations of these structures are use of ground floor as car parking in residential buildings, use of basement as car parking in malls, etc. Seismic range is one the most important factors to be considered to analyze any irregular structure. In this study, the design of different G+6 structures having vertical regularity was done. These irregular structure models were compared with a regular G+6 structure having similar properties as other structures. For the designing and analysis of these structures, use of StaadPro software was done. It is one of the most used software, whenever it comes to the digital analysis of any structure. Different types of Vertical irregularities like mass irregularity, Vertical Setback Irregularity, Stiffness Irregularity (Discontinuous Column, Middle weak storey and Bottom Weak Storey) were considered for the analysis. The Seismic Zone for the structure is considered to be Delhi (Seismic Zone IV) with a Seismic Factor of 0.24. All the model structures were compared for the parameters of their Storey Drift and Storey Displacement. For irregular buildings though, certain damages/fatigue may be observed in some structures but the structures will not fail and will be serviceable for a long time with proper care. It was observed that the structures with stiffness irregularity showed the most increase in storey displacement and storey drift values.

The rise in irregular building construction, driven by esthetics and limited land availability, has led to increased vulnerability to lateral loads. Designers are adopting response control systems (RCSs) to ensure occupant safety and mitigate the risk of structural failure. Among the widely used RCSs are base isolators and dampers. This study examines the use of base isolators and viscoelastic dampers in 10‐story L‐shaped reinforced concrete buildings. The research evaluates buildings equipped with RCSs individually and in combination, analyzing parameters such as peak story displacement, inter‐story displacement ratio (ISDR), and peak story shear. The findings reveal that incorporating viscous energy dissipators (VEDs) at the edges of base‐isolated buildings significantly reduces structural responses. Specifically, reductions of up to 62.27% in peak story displacement, 52.03% in ISDR, and 64.72% in peak story shear are achieved compared to a fixed‐base structure. These results demonstrate that combining base isolators with strategically placed VEDs is highly effective in enhancing the performance of L‐shaped RC buildings under lateral loads. The study concludes that edge placement of VEDs in base‐isolated structures provides optimal response mitigation, offering a promising solution for improving the resilience of irregularly shaped buildings.

PurposeNear-fault pulse-like ground motions have distinct and very severe effects on reinforced concrete (RC) structures. However, there is a paucity of recorded data from Near-Fault Ground Motions (NFGMs), and thus forecasting the dynamic seismic response of structures, using conventional techniques, under such intense ground motions has remained a challenge.Design/methodology/approachThe present study utilizes a 2D finite element model of an RC structure subjected to near-fault pulse-like ground motions with a focus on the storey drift ratio (SDR) as the key demand parameter. Five machine learning classifiers (MLCs), namely decision tree, k-nearest neighbor, random forest, support vector machine and Naïve Bayes classifier , were evaluated to classify the damage states of the RC structure.FindingsThe results such as confusion matrix, accuracy and mean square error indicate that the Naïve Bayes classifier model outperforms other MLCs with 80.0% accuracy. Furthermore, three MLC models with accuracy greater than 75% were trained using a voting classifier to enhance the performance score of the models. Finally, a sensitivity analysis was performed to evaluate the model's resilience and dependability.Originality/valueThe objective of the current study is to predict the nonlinear storey drift demand for low-rise RC structures using machine learning techniques, instead of labor-intensive nonlinear dynamic analysis.

Buckling restrained brace frames (BRBFs) exhibit exceptional lateral stiffness, load-bearing capacity, and energy dissipation properties, rendering them a highly promising choice for regions susceptible to seismic activity. The precise and expeditious prediction of seismic demands on BRBFs is a crucial and challenging task. In this paper, the potential of artificial neural networks (ANNs) to predict the seismic demands of BRBFs is explored. The study presents the characteristics and modelling of prototype BRBFs with different numbers of stories and material properties, utilising the OpenSees software (Version 2.5.0) for numerical simulations. The seismic performance of the BRBFs is evaluated using 91 near-fault pulse-like ground motions, and the maximum inter-storey drift ratio (MIDR) and global drift ratio (GDR) are recorded as a measure of seismic demand. ANNs are then trained to predict the MIDR and GDR of the selected prototypes. The model’s performance is assessed by analysing the residuals and error metrics and then comparing the trend of the results with the real dataset. Feature selection is utilised to decrease the complexity of the problem, with spectral acceleration at the fundamental period (T) of the structure (Sa), peak ground acceleration (PGA), peak ground velocity (PGV), and T being the primary factors impacting seismic demand estimation. The findings demonstrate the effectiveness of the proposed ANN approach in accurately predicting the seismic demands of BRBFs.

In this paper (G+8) building is modeled like a bare frame, a bare frame with the shear wall, and a bare frame with X bracing by changing the soft storey to different floors. The static analysis effect is determined for all three models with zone IV and zone V using Staad pro-V8i software. The main objective of the research was to assess the impact of a soft storey in various earthquake zones and by varying places of the soft storey from first to the top floor and for frames with different column shapes by seismic analyses in staad pro. The results of variable building models are obtained from the research regarding various parameters such as displacement, storey drift, and base shear. More significantly, comparing different structural systems revealed a reduction in lateral displacement and story drift. The shear wall reduced the Storey Displacement by 98.838% and storey drift by 99.86%. The Steel bracing reduced the Storey Displacement by 97.846 % and storey drift by 92.6%. Finally, it has been found that the Shear wall reduces lateral displacement and storey drift, thus significantly contributing to greater structural stiffness. The analysis results recommended that the shear wall use reinforced concrete frames for the seismic hazard zones and the Steel bracing recommended for the low seismic zones.

The demand for modular steel buildings (MSBs) has increased because of the improved quality, fast on-site installation, and lower cost of construction. Steel braced frames are usually utilized to form the lateral load resisting system of MSBs. During earthquakes, the seismic energy is dissipated through yielding of the components of the braced frames, which results in residual drifts. Excessive residual drifts complicate the repair of damaged structures or render them irreparable. Researchers have investigated the use of superelastic shape memory alloys (SMAs) in steel structures to reduce the seismic residual deformations. This study explores the potential of using SMA braces to improve the seismic performance of typical modular steel braced frames. The study utilizes incremental dynamic analysis to judge on the benefits of using such a system. It is observed that utilizing superelastic SMA braces at strategic locations can significantly reduce the inter-storey residual drifts.

In the current study, the response of flat, grid and conventional slab against seismic excitation is studied and comparative analysis is performed to establish which among the three slab system would be most effective and safe in an earthquake scenario. The parameter such as storey displacement, drift, shear, and base shear of each slab arrangement is extracted from ETABS which is general structural design software for comparison. In the analysis, three different building specimen with the aforementioned slab type having length, width and height of 40m, 30m and 30m respectively are designed as per Indian design code IS: 456:2000 and analyzed as per IS:1893:2016.