Analysis of the structural performance of the Cakung house in East Jakarta aims to determine the behavior and performance of the building by using the Special Moment Bearing Frame system (SRPMK). ...Evaluation is carried out on the performance of the building structure by using a structural analysis aid program. And the lateral force capacity that the system can withstand is 1592432.05 Kgf in the X direction and 643948.61 Kgf in the Y direction. Where the pushover analysis using the ATC 40 method, the melting point occurred for the first time at a displacement of 23.57 cm in the X direction and 7.28 cm in the Y direction. And serious damage occurred at the displacement of 77.49 cm in the X direction and 94.84 in the Y direction. The analysis found that the drift ratio value of the maximum total deviation and the maximum inelastic deviation that occurs in the structure is less than 1%. So that the level of performance of the design is in the category of Immediate Occupancy (IO).
The present work addresses the topic of automated calibration of numerical models starting from the experimental characterization of the structure’s dynamic behaviour. The importance of the topic is ...well known in the literature, especially in cases where it is necessary to have at disposal validated numerical models, necessary for the correct evaluation of the safety of existing buildings. Generally, the calibration problem is developed with a manual approach (manual tuning), with a positive outcome whenever there is a good knowledge of the boundary and internal constraint conditions and the elastic mechanical properties of the construction’s constituent materials. Conversely, the positive outcome is particularly difficult to achieve manually when there are non-homogeneous and/or complex structures, as in the cases of historic masonry structures, which are often the result of constructions carried out at different times, organized in aggregates whose interaction between the portions is not simple to understand. For this purpose, the present work, using commercial software and specially prepared routines, illustrates a semi-automatic procedure, which employs genetic algorithms, suitable for the optimized identification of the numerical model that best represents the structure’s experimental dynamic behaviour. The procedure is presented with reference to two case studies: the Gabbia Tower historic masonry aggregate in Mantua and the bell tower of the Monastery of the Ursuline nuns in Capriolo, Brescia. In the first case, in addition to the experimental dynamic characterization, a good instrumental characterization of the tower’s masonry mechanical properties is available. In the second case, alongside a good experimental dynamic characterization, only a qualitative estimate of the masonry mechanical properties, based on visual inspections, is available. The two case studies allow for testing the validity of the numerical models’ calibration procedure, necessary for their application in the field of safety checks. Finally, for the case studies analysed the work presents an assessment of seismic vulnerability starting from the models identified with the semi-automatic procedure. The seismic vulnerability assessment was obtained using non-linear static analysis following the N2 method.
•Calibration procedure for FE models based on OMA and genetic algorithms.•FEM calibration of historical masonry towers within building aggregates.•Identification of the interaction between the structure and neighbouring buildings.•Effects of adjacent buildings on tower’s damage mechanisms.•Seismic safety assessment of masonry towers through pushover analyses.
Kilometer-span cable-stayed bridges usually adopt tall inverted Y-shaped pylons. Such pylons may behave inelastically under strong transverse seismic excitations. Therefore, efficient analysis ...methods (e.g., pushover analysis) for transverse elastoplastic behavior assessments of inverted Y-shaped pylons are of great interest for academic and industrial communities. Based on equal displacement rule, this study proposes an applied deformation-based pushover analysis (DPA) incorporating a novel multi-node load pattern for the efficient transverse seismic behavior assessments of inverted Y-shaped pylons in kilometer-span cable-stayed bridges. A case study of the inverted Y-shaped pylon of Sutong Bridge is adopted to demonstrate the proposed DPA. The proposed multi-node load pattern for DPA is verified through the validation of the loaded-node selection and equal displacement rule for the studied pylon. The ability of DPA in seismic behavior assessments is then systematically validated by comparative studies with incremental dynamic analysis (IDA), conventional pushover analysis (CPA), and modal pushover analysis (MPA) in terms of displacement, bending moment and curvature responses of pylon as well as computational costs.
•A novel deformation-based pushover analysis (DPA) is proposed for tall inverted Y-shaped bridge pylons.•A multi-node load pattern is proposed for the DPA method to avoid premature local failure.•The equal displacement rule is validated for tall bridge pylons.•DPA can be employed for transverse seismic behavior evaluation of inverted Y-shaped pylons.
For structural engineers, existing surrogate models of buildings present challenges due to inadequate datasets, exclusion of significant input variables impacting nonlinear building response, and ...failure to consider uncertainties associated with input parameters. Moreover, there are no surrogate models for the prediction of both pushover and nonlinear time history analysis (NLTHA) outputs. To overcome these challenges, the present study proposes a novel framework for surrogate modelling of steel structures, considering crucial structural factors impacting engineering demand parameters (EDPs). The first phase involves the development of a process by which 30,000 random steel special moment resisting frames (SMRFs) for low to high-rise buildings are generated, considering the material and geometrical uncertainties embedded in the design of structures. In the second phase, a surrogate model is developed to predict the seismic EDPs of SMRFs when exposed to various earthquake levels. This is accomplished by leveraging the results obtained from phase one. Moreover, separate surrogate models are developed for the prediction of SMRFs’ essential pushover parameters. Various machine learning (ML) methods are examined, and the outcomes are presented as user-friendly GUI tools. The findings highlighted the substantial influence of pushover parameters as well as beams and columns’ plastic hinges properties on the prediction of NLTHA, factors that have been overlooked in prior studies. Moreover, CatBoost has been acknowledged as the superior ML technique for predicting both pushover and NLTHA parameters for all buildings. This framework offers engineers the ability to estimate building responses without the necessity of conducting NLTHA, pushover, or even modal analysis which is computationally intensive.
•Generated 30,000 random steel buildings for surrogate model development.•Established novel design of experiment framework for surrogate modelling.•Used material, geometry, seismic, and pushover factors for surrogate development.•Developed GUIs for pushover and time history analysis prediction.•Used 13 ML methods for building response prediction with advanced feature selection.
Electricity transmission system is well recognized as a lifeline system in the modern society, and its failures in past major earthquakes have aroused the concern about its seismic vulnerability. In ...the present study, fragility curves are developed to assess the vulnerability of a typical transmission tower subjected to near-field ground motions. A probabilistic seismic demand model (PSDM) is constructed for the transmission tower in terms of the maximum inter-segment drift ratio (ISDR) and the spectral acceleration (Sa) at the fundamental period of the structure. Pushover analysis is performed to define the capacity limit states for the transmission tower, which are serviceability, damage control and collapse prevention in this research. The data for the PSDM are acquired by using incremental dynamic analyses (IDAs) of a suite of seismic records. Additionally, the influence of the seismic incident angles and the coupling effect between the transmission tower and lines on the structural fragility are further investigated. The results quantify the seismic vulnerability of the transmission tower and demonstrate the influence of the seismic incident angles and the dynamic coupling effect between the transmission tower and lines.
•A new probabilistic seismic demand model is constructed for the transmission tower•Fragility curves are developed for the transmission tower subjected to near-field ground motions•Influence of the seismic incident angles and the dynamic coupling effect on the structural fragility are investigated.
•Energy efficiency of RH structures reaches a higher peak under inclined loads.•Energy efficiency of RH structures is high at the early stages of uniform compression.•Significant reduction in mean ...crushing force is observed for RH structures at inclined loads.•A new transition stage is induced under inclined loads.•New micro modes (‘distorted X’, and ‘>’ modes) for RH structures emerge under inclined loads.
The present study unravels the deformation mechanisms observed during the static inclined compression of re-entrant honeycomb (RH) auxetic structure. A pushover Riks analysis is conducted by facing a rigid plate towards the structure at various angles. A new ‘plastic hinge tracing method’ is introduced to systematically extract the micro deformation mechanisms under inclined loading. The identified modes are related to the macro deformation regime and the overall mechanical response of the RH structure. Moreover, their relation to various measures of efficiency is elaborated. It is shown that a transition stage emerges under inclined loading, which delays achieving the peak energy efficiency. The overall energy dissipation decreases in the inclined cases but interestingly, the performance of the RH structure does not deteriorate. Namely by maintaining a low crushing force under inclined loads, the trade-off of low energy dissipation is balanced and a lower impact is anticipated. Finally, the similarities between the transition stage and the macro modes are highlighted and further directions for investigation are proposed.
In earthquake-prone regions such as Indonesia, this situation has drawn public attention and led to difficulties in implementing certain policies and decision-making. One of the challenging issues in ...seismic risk reduction is evaluating the efficacy of seismic retrofitting the existing low-to-mid reinforced concrete building. Therefore, this research evaluates the retrofitting of low-to-mid-rise reinforced concrete structures to evaluate the efficacy of the retrofitting strategy rationally using Fiber Reinforced Plastic (FRP), Buckling Restrained Braced Frame (BRBF), and shear wall strategies. Rusunawa at Cilacap, a mid-rise RC apartment for low-income people, was selected as a benchmark building to compare existing and retrofitted seismic fragility. Furthermore, a 3D computer model was developed to predict the seismic response of the structure using a nonlinear static (pushover) analysis. The pushover method produces a capacity curve, showing that the unreinforced structure has a maximum base shear value of 15.2x103 kN. While the reinforcement of low to medium rise reinforced concrete structures using the Fiber Reinforced Plastic strategy has a maximum base shear value of 15.3x103 kN, then reinforcement using the Buckling Restrained Braced Frame strategy with a maximum base shear value of 16.2x103 kN. The shear wall reinforcement has a value maximum base shear of 19.7x103 kN. The capacity curves as the analysis outputs were then converted into the fragility and used to rationalize the probabilistic value of the damage states between existing and retrofitted buildings.
