Papers by Keyword: Incremental Dynamic Analysis

Abstract: Earthquakes cause deformations in structural elements which then lead to interstory drift and probability of collapse in building structures. Incremental Dynamic Analysis (IDA) will obtain a graph containing the Response Spectral Acceleration (RSA) value for the maximum interstory drift ratio, which will then be used to calculate the probability of collapse using the Fragility Curve. The structure is planned to be located in Biak city on hard soil conditions with a 16-story two-dimensional SRPMK building model. Various ground motions scaled to the design response spectrum of Biak city with 2 different methods were used. Based on the analysis conducted, the average interstory drift value for RSA scaling (T1) is 0.33 meters and RSA scaling (T1 = 0) is 0.2 meters, both of which occur on the first floor of the building structure. The largest RSA value obtained through IDA for the RSA scaling (T1) was 1.63 g and the RSA scaling (T1 = 0) was 1.89 g. Through the Fragility Curve, the probability of structural collapse at an RSA value of 1.63 g is 0.99 and at an RSA value of 1.89 g is 0.75.

Abstract: The first case study used in this work is an existing seven-storey unreinforced masonry building (representing a typical residential building located in the district of L ́Example in Barcelona). The accuracy of the non-linear static procedures was evaluated by comparison with non-linear dynamic analyses for seven ground motion records and different levels of seismic intensity. The results obtained from the analyses showed good performance of the static pushover methods on the analysed building. The second case study used in this work is a two-storey unreinforced masonry building which was tested at ELSA in Ispra, Italy. First a modal response spectrum analysis was carried out. Subsequently, non-linear static analysis was performed using two different computer programmes. The results of the present work were compared with experimental results.

Abstract: Incorporating the probability of seismic hazard, expected annual earthquake loss with different collapse margin ratio (CMR) has been studied in this paper. Nonlinear simulation models of reinforced concrete (RC) frames were analyzed using incremental dynamic analysis (IDA) under continuous earthquake intensity. The analytic results from four examples of RC frames show that the expected annual loss has negative correlation with the CMR of the concerned structures, and seismic loss basically decreases with increasing CMR at given ground motion intensity. The proposed idea herein could be regarded as a promising improvement on the quantification of earthquake loss estimation by utilizing CMR of structures.

Abstract: Based on the time-history analysis principle of bidirectional equivalent tension rod of steel shear wall in this paper, the theory of Incremental Dynamic Analysis (IDA) is used to investigate the real seismic behavior of steel frame-steel plate shear wall (SPSW) system under a large number of natural earthquake waves and artificial simulated earthquake waves with the gradually increased scale of seismic intensity in order to achieve the base shear-roof displacement (V-Δ) curve under each earthquake wave action. Based on the principle of unidirectional equivalent tension rod, the pushover analysis is also used to obtain the curve of base shear and roof displacement under two different loading modes of uniform distribution and inverted triangular distribution. Through the above two different methods of seismic behavior evaluation, the achieved conclusions are as follows: The most V-Δ envelope curves obtained by IDA analysis are between V-Δ envelope curves obtained by pushover analysis under these two loading modes of inverted triangular and uniform distribution. With the increase of structural storey, the effect of high order mode on seismic behavior is more and more obvious and the deviation of calculation results derived from pushover is bigger and bigger. As a result, pushover analysis is only applied to evaluate seismic performance of structure at the middle or low storey. For the pushover, the structural bearing capacity and initial stiffness is underestimated, but the structural deformation capacity is overestimated under inverted triangular loading mode, Whereas, it is the opposite situation under the uniform distribution.

Abstract: In this research, analytical fragility curves for three existing structures are presented. Structures are 2-story, 6-story and 10-story residential reinforced concrete structures designed under dead ,live and seismic loads of zone 3 according to Egyptian code (2008). The design acceleration is 0.15g. The fragility curves are developed based on nonlinear incremental dynamic analysis of three dimensional structural models using SeismoStruct under twelve historic ground motions. Four performance levels are considered; fully operational, operational, life safe and near collapse.

Abstract: Seismic damage was the key reason which resulted in the serviceability degradation or collapse of the bridge. How to quantify the seismic damage and evaluate the seismic performance of the bridge under earthquakes through the damage analysis was the significant research direction in the performance based seismic design. In this paper the Park-Ang model (a well-known dual parameters model) and its modification version used for the damage evaluation of the concrete structure were compared. Furthermore, through the definition of the damage indices of the models based on the modified Park-Ang model and the descending slope of the IDA(incremental dynamic analysis) curve, the seismic damage levels of the typical bridge in the urban rail transit line under the designated earthquakes were analyzed, respectively. It was shown from the results that the calculated results from the two model was essentially consistent. The damage analysis based evaluation method was feasibly used for the seismic performance evaluation of the bridge.

Abstract: Suspended dome is a reasonable and novel type of long-span hybrid spatial structures based upon single-layer spherical lattice shell and tensegrity system. Based upon the structural force-bearing characteristics, the combined finite element model of beam elements, truss elements and cable elements is set up. A method taking the maximum displacement on nodes under earthquake acceleration of each level as dynamic response representative parameter is proposed to study the dynamic stable ultimate capacity of suspended dome by application of the incremental dynamic analysis in combination with B-R kinetic criterion. Furthermore, considering suspended dome has the clear advantage over Single-Layer Spherical Lattice Shell for a structure with a long span and a small ratio of rise to span, the influences of factors such as structural parameters, geometric parameters, and different earthquake input are investigated on dynamic stability for a kiewitt-type suspended dome with a long span and a small ratio of rise to span. Finally of suspended dome some conclusions are obtained such as the initial defects can clearly reduce dynamic stable ultimate capacity, and since the rise-span ratio, pre-stressing level and cross section area are not monotonous as variety to the structural dynamic stability, they should be optimized to enhance or improve the structural dynamic stability, which can be rules for engineering design.

Abstract: The structure influencing coefficients reflect discount rate on horizontal seismic action of different structure categories. In general, the structure influence coefficients are related with the ductility level and overstrength of the structure. According to Code for seismic design of buildings (GB50011-2008), four models of three story-steel frames are designed for 4 types of site. Dynamic time-history analysis is carried out to study the models with records of seismic waves. The ductility level, the over-strength and Structural Influencing Coefficient are derived by the energy concept in the different sites condition. Structural Influencing Coefficient based on the energy concept is a new attempt. Method of the energy concept and design of structure will become the important development direction to improve the traditional seismic design.

Abstract: Selection and modification of recorded earthquake ground motions is one of the most important issues for reliable seismic performance evaluation of the structure. In order to investigate the influence of ground motion spectral shape on nonlinear seismic response and to find the implication for ground motion selection and modification, a 3-storey RC planar frame is taken as case study in this paper. 15 ground motion records are chosen from PEER Ground Motion Database and Wenchuan Great Earthquake as dynamic analysis inputs.

Abstract: Seismic analysis and design based on collapse probability under intense earthquakes is the main trend in the field of earthquake engineering. Accurate evaluation of collapse resistance capacity is necessary to achieve this target. Due to the accumulated deformation during seismic excitations, structural components would have different stiffness and strength deterioration characteristics. For evaluating the collapse capacity of the structure, it is important to take into account the deterioration characteristics in the analytical model. In this paper, the constitutive models for concrete and reinforcing steel, especially those adopted in OpenSees analytical software, are reviewed first. Then, a reinforced concrete single-storey planar frame structure with one bay is taken as case study and the effect of post-capping strength deterioration of reinforcing steel on evaluation results of global collapse resistance capacity is mainly investigated by incremental dynamic analysis (IDA) via OpenSees software. Analytical results show that global collapse resistance capacity will be significantly overestimated without considering the effect of post-capping strength deterioration of reinforcing steel.