This study presents experimental results on the seismic behavior of a large-scale two-bay, two-story RC frame with RC infill walls, including openings typical of low-rise RC row buildings in Taiwan. ...The test findings indicated that the specimen failed due to the failure of the vertical members of the first story. Specifically, the critical wall segments located between openings and between an opening and a boundary column and short columns resulting from the presence of these openings were shown to be the main contributors to the failure. Based on the observed phenomenon during the test, an analytical model was verified and proposed for the tested specimen’s pushover analysis. The selection of plastic hinges in the analytical model was determined according to the Taiwan Earthquake Assessment for Structures by Pushover Analysis (TEASPA). Pushover analysis performed by commercially available software indicated that the analytical model could well capture the specimen's behavior regarding peak base shear, initial stiffness, displacement of each story, and development of plastic hinges.
•Cyclic test on a two-bay, two-story reinforced concrete frame infilled with walls with openings.•Failure of the frame dominated by critical wall segments and short columns.•Critical wall segments are those between openings and between opening and boundary columns•A pushover model is proposed for frames infilled with walls with openings.
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).
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.
•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.
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.
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.
•Nonlinear static analyses for the seismic assessment of masonry buildings.•Seismic assessment of existing complex masonry buildings with flexible floors.•Vulnerability assessment of mixed ...masonry–reinforced concrete buildings.•Reliable models and strength criteria for masonry pier and spandrel elements.•An advanced modelling tool useful both at research level and engineering practice.
The seismic analysis of masonry buildings requires reliable nonlinear models as effective tools for both design of new buildings and assessment and retrofitting of existing ones. Performance based assessment is now mainly oriented to the use of nonlinear analysis methods, thus their capability to simulate the nonlinear response is crucial, in particular in case of masonry buildings. Among the different modelling strategies proposed in literature, the equivalent frame approach seems particularly attractive since it allows the analysis of complete 3D buildings with a reasonable computational effort, suitable also for practice engineering aims. Moreover, it is also expressly recommended in several national and international codes. Within this context, the paper presents the solutions adopted for the implementation of the equivalent frame model in the TREMURI program for the nonlinear seismic analysis of masonry buildings.
