Papers by Keyword: Incremental Dynamic Analysis (IDA)

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Authors: Hyung Suk So, Yeong Seok Yoo, Andreas Schaeffer
Abstract: To develop the extraction media for Cd and Ni from aqueous solutions, magnetic beads containing IDA group with strong attraction to heavy metals were produced using the activating agents Epichlorhydrin (Ep) and 1,4-Butanedioldiglycidylether (Bu), respectively. Then the beads were agitated at a pH of 6 after being added to Cd and Ni aqueous solutions of various concentrations. It was confirmed that the heavy metals combined with the magnetic beads within a short time through the process. After the process, the magnetic beads were collected with a magnet, and then dissolved in acid for the analysis of heavy metal concentration. The analysis of heavy metals in the acid solution could be analyzed with an AAS (atomic absorption spectrometer). The results showed that the heavy metal extraction efficiency of Bu was relatively higher than that of the Ep. It supported the hypothesis that the relatively longer length of Bu’s spacer made more free positioning possible when the IDA group combined with the heavy metal.
Authors: Yong Sheng Qi, Feng Hua Zhao, Jun Wen Zhou
Abstract: Non-convergence often occurs in the solution of highly nonlinear problem by conventional implicit finite element method. As another choice, explicit method is sometimes used by researchers. Through 2 typical static and dynamic examples this paper verifies that explicit finite element method can provide the same exactness of calculation as the implicit method even in the situation that the duration of action exceeds the natural period of structure greatly. At the same time, compared with implicit method, explicit method possesses higher speed, more robust algorithm, and stronger nonlinear capability, so that explicit method can be applied in static and dynamic analysis of structures, especially in large deformation and highly nonlinear problem.
Authors: Ryota Matsui, Toru Takeuchi, Shunji Urui, Masaki Tokuno
Abstract: The 2011 Tohoku Earthquake ruptured multiple faults simultaneously, generating strong ground motions over a long duration at long periods. Such severe events have recently begun to be considered in structural design, requiring explicit calculation of the low cycle fatigue capacity and fracture point. This paper presents a numerical study of dual moment and braced frames, with either conventional or buckling-restrained braces. Both brace and beam end fracture is considered, and incremental dynamic analysis (IDA) used to determine the ultimate failure mechanism under extremely large ground motions. Fragility curves are generated, demonstrating the significant role that member fracture has on the seismic performance of braced frames.
Authors: Gianfranco de Matteis, Giuseppe Brando
Abstract: This paper deals with the seismic response of dual steel frames with and without dissipative metal shear panels. The main goal is to define possible design criteria, for the seismic protection of new and existing buildings, accounting for the main behavioral peculiarities of metal shear panels.To this purpose, based on a large number of historical records that are selected in order to match the main interesting frequencies, Incremental Dynamic Analyses (IDAs) are carried out on two steel frames. These frames have been first designed in order to satisfy specific performances. Then, they have been improved by imposing stricter design goals that have been complied with the application of dissipative metal shear panels.The obtained outcomes highlight that metal shear panels allow to control properly the collapse mechanisms of the frames. Moreover, they can lead to significant increases of collapse accelerations and to a general reduction of both the permanent and the transient story drifts. The paper concludes with the evaluation of the equivalent q-behaviour factor of both the protected and the un-protected frames. As it could be expected, the most effective shear panels are able to produce stronger increase of behavior factors (up to 150%), due to the larger dissipative capacity of the whole structure.
Authors: Saber Moradi, M. Shahria Alam
Abstract: Incremental Dynamic Analysis (IDA) is a technique to determine the overall seismic performance of structures under varied intensities of earthquakes. In this paper, the seismic performance of four-story steel braced frames equipped with superelastic Shape Memory Alloy (SMA) braces is assessed by performing IDA. The seismic response of SMA-braced frames was compared to that of corresponding Buckling-Restrained Braced Frames (BRBFs). Based on the results of this comparative study, the SMA-braced frames were generally effective in reducing maximum interstory drifts and permanent roof deformations. In addition, the SMA-braced frames demonstrated more uniform drift distribution over the height of the building. As the intensity of earthquake excitation increases, a higher response reduction can be expected for SMA-braced frames.
Authors: Zhi Qian Dong, Gang Li, Hong Nan Li
Abstract: Steel concentrically-braced frames (CBFs) as a lateral force resisting system are widely used in moderate seismic regions. The collapse capacity of CBF is uncertain in prior study so that an appropriate analysis method is hard to hunt. Incremental Dynamic Analysis (IDA) is an efficient method to evaluate the dynamic instability of structure. The IDA is incorporated in evaluation of collapse capacity of CBFs systems and IDA-based collapse ductility spectra of CBFs are concluded in this study. Variable periods range of CBFs systems considering reserve capacity are determined based on the IDA.
Authors: Wen Xia Yang, Qiang Gu, Zhen Sen Song
Abstract: In current seismic design procedure, structural base shear is calculated according to the linear elastic response spectra divided by response modification factor R. The response modification factor is important to the reliability and economy of building seismic design. In this paper, the response modification factors of Twelve Y-eccentric braced steel frames with various stories and spans lengths were evaluated by capacity spectrum method based on the global capacity envelops obtained from an improved pushover analysis and incremental dynamic analysis. According to the results, an appropriate formula of the response modification factor for the Y-eccentric braced steel frames was suggested.
Authors: Abhishek Verma, Dipti Ranjan Sahoo
Abstract: Steel Plate Shear Walls (SPSWs) have proven to be efficient lateral force-resisting systems. SPSWs utilize the post-yielding strength of the unstiffened web plates, which makes the system economically viable. ANSI/AISC 341-10 suggests the value of response modification factor for SPSWs to be 7, which is based on judgment and qualitative comparisons with response capabilities of previously well-studied systems. This study is focused on the evaluation of the seismic performance factors for SPSW systems through the collapse analysis in accordance with FEMA P695 recommendations. Three-and six-story SPSWs are considered in the study. Aspect ratio of the web plates is varied to obtain the archetypes. Numerical models of the study frames are developed and analyzed using a computer software OpenSees. The modelling technique is validated by comparing the predicted hysteretic response with the past experimental results. Both nonlinear static and dynamic analyses are conducted for the study frames. The results of the collapse analysis are presented and the values of seismic performance factors given in ANSI/AISC 341-10 are verified. Collapse mechanisms of the models for each ground motion are identified and a probability analysis is carried out to identify the most probable mechanisms. Further, suggestions are provided to avoid unnecessary over-strengthening and to ensure adequate collapse margin ratio.
Authors: Emanuele Brunesi, Roberto Nascimbene, Gian Andrea Rassati
Abstract: Partially restrained (PR) bolted beam-to-column connections are a promising typology of connection in modern steel moment resisting frames (MRFs). Both high-fidelity three-dimensional solid models and mechanics-based idealisations have been extensively explored in order to investigate the behaviour of this attractive solution, applicable both to new construction and to retrofitting of existing structures. Despite this, structural safety has been probabilistically assessed and controlled in a relatively few cases, thus neglecting characterisation, modelling and propagation of uncertainties. As such, this paper moves from a deterministic to a probabilistic framework, proposing fragility models at multiple damage states for low-and medium-rise MRF structures with T-stub and top-and-seat angle connections which may be applied for seismic risk assessment and management. After validation against past experimental data, use was made of component-based modelling to reproduce the seismic response of these PR bolted connection systems within planar MRFs designed for earthquake resistance in accordance with current European rules. A set of 44 records scaled at increasing seismic intensity was considered to perform a series of incremental dynamic analyses (IDAs). Fragility functions for each damage state of interest were then derived and compared. The analysis results show the influence of connection typology and structure height.
Authors: Shan Suo Zheng, Wen Bo Li, Qian Li, Fan Wang
Abstract: With the rapid development and extensive application of SRC (steel reinforced concrete) frame structures, the study on seismic fragility of SRC structure under earthquakes seems rather important. The seismic fragility of the SRC frame structures is studied by the method of Incremental Dynamic Analysis (IDA) in this paper. IDA method is conducted on 9 storey SRC frame structure to obtain the IDA curves of this model. Meanwhile, the seismic fragility of the model is analyzed to get the fragility curve. The result shows that IDA can describe the quantitative relationship between the exceeding probability of different states and damage degree of the target.
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