scholarly journals A Prediction Model for the Calculation of Effective Stiffness Ratios of Reinforced Concrete Columns

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1792
Author(s):  
Sourav Das ◽  
Iman Mansouri ◽  
Satyabrata Choudhury ◽  
Amir H. Gandomi ◽  
Jong Wan Hu

Nonlinear dynamic analyses of reinforced concrete (RC) frame buildings require the use of effective stiffness of members to capture the effect of cracked section stiffness. In the design codes and practices, the effective stiffness of RC sections is given as an empirical fraction of the gross stiffness. However, a more precise estimation of the effective stiffness is important as it affects the distribution of forces and various demands and response parameters in nonlinear dynamic analyses. In this study, an evolutionary computation method called gene expression programming (GEP) was used to predict the effective stiffness ratios of RC columns. Constitutive relationships were obtained by correlating the effective stiffness ratio with the four mechanical and geometrical parameters. The model was developed using a database of 226 samples of nonlinear dynamic analysis results collected from another study by the author. Subsequent parametric and sensitivity analyses were performed and the trends of the results were confirmed. The results indicate that the GEP model provides precise estimations of the effective stiffness ratios of the RC frames.

1998 ◽  
Vol 25 (5) ◽  
pp. 803-818 ◽  
Author(s):  
Kent A Harries ◽  
Denis Mitchell ◽  
Richard G Redwood ◽  
William D Cook

The design and nonlinear dynamic analyses of four coupled wall prototype structures are presented. Two ductile partially coupled and two ductile coupled wall structures are considered, each having reinforced concrete and steel coupling beams. The design of each of the prototype structures was based on the provisions of the 1995 National Building Code of Canada. Nonlinear dynamic analyses of each structure, using four different scaled earthquake ground motions are presented and the results discussed. Comparisons of the responses of the structures with concrete and steel coupling beams are made, demonstrating the advantages of using steel beams to couple reinforced concrete walls.Key words: composite construction, coupled wall, diagonally reinforced concrete coupling beam, "flexure critical" steel coupling beam, seismic design, "shear critical" steel coupling beam.


2014 ◽  
Vol 1065-1069 ◽  
pp. 1438-1442
Author(s):  
Dong An ◽  
Tie Jun Qu

The selection of input ground motion for seismic analysis of the structure is a complicated task, especially when nonlinear dynamic analysis is utilized. A decision has to be made regarding the intensity measure better to represent the potential damage of the ground motion. This paper presents a lot of analysis to deal with the problem. A set of nonlinear dynamic analyses were conducted on reinforced concrete buildings widely present in China. Input ground motions contain uncertainty and variability comes from both natural recordings and synthetic data. First, a set of natural recordings is considered. Second, two ground motion modification schemes are used in this study: magnitude scaling and spectrum matching. Third, a set of ground motion is synthesized. The peak value of displacement has been selected as the response parameter better able to represent the structural damage level. Nonlinear dynamic analyses of reinforced concrete buildings simulated by OpenSEES are carried out to evaluate the correlation coefficients of displacement response and the chosen ground motion parameters. Findings from the investigation indicate that the Housner intensity is the more effective intensity measure for selecting the seismic input. The synthesized ground motion fit with code spectrum shows good performance as a design input motion. Considering ground motion modification, spectrum matching is generally more stable in response prediction than scaling.


2014 ◽  
Vol 711 ◽  
pp. 477-480
Author(s):  
Dong An ◽  
Tie Jun Qu

The choice of input ground motion in the evaluation of the seismic response is a complicated task. The ground motion parameters need to be determined by the scope of the analysis and the potential damage of new or existing buildings. This work presents nonlinear dynamic analyses on reinforced concrete frame widely present in China. Input ground motions contain uncertainty and variability comes from both natural recordings and modified ones. Magnitude scaling and spectrum matching are used in this study. Nonlinear dynamic analyses of reinforced concrete buildings simulated by SeismoStruct and OpenSEES are carried out to evaluate the seismic response. Findings from the investigation indicate that spectrum matching is generally stable and shows good performance in response prediction.


Author(s):  
Mohamed Cherif Djemai ◽  
Mahmoud Bensaibi ◽  
Fatma Zohra Halfaya

Bridges are commonly used lifelines; they play an important role in the economic activity of a city or a region and their role can be crucial in a case of a seismic event since they allow the arrival of the first aid. Reinforced concrete (RC) bridges are worldwide used type view their durability, flexibility and economical cost. In fact, their behavior under seismic loading was the aim of various studies. In the present study the effect of two structural parameters i.e. the height and the type of piers of reinforced concrete bridges on seismic response is investigated. For that reason, different multi-span continuous girder bridges models with various geometrical parameters are considered. Then, non-linear dynamic analyses are performed based on two types of piers which are: multiple columns bent and wall piers with varying heights. In this approach, a serie of 40 ground motions records varying from weak to strong events selected from Building Research Institute (BRI) strong motion database are used including uncertainty in the soil and seismic characteristics. Modelling results put most emphasis on the modal periods and responses of the top pier displacements, they show the influence of the considered parameters on the behavior of such structures and their impact on the strength of reinforced concrete bridges.


2010 ◽  
Vol 133-134 ◽  
pp. 715-720 ◽  
Author(s):  
Ilaria Senaldi ◽  
Guido Magenes ◽  
Andrea Penna

The work focuses on the analysis of the seismic response of masonry building aggregates for a better understanding of the vulnerability of single structural units and of their behaviour within the aggregates. Idealized representative models are developed based on the typical characteristics of the row conglomeration typology. The seismic response of the models is evaluated and discussed by means of nonlinear dynamic analyses.


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