scholarly journals Determination of Damage in Reinforced Concrete Frames with Shear Walls Using Self-Organizing Feature Map

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Mehdi Nikoo ◽  
Łukasz Sadowski ◽  
Faezehossadat Khademi ◽  
Mohammad Nikoo
Keyword(s):  
Reinforced Concrete ◽  
Learning Algorithm ◽  
Nonlinear Dynamic Analysis ◽  
Shear Walls ◽  
Concrete Frames ◽  
Function Type ◽  
Reinforced Concrete Frames ◽  
Feature Map ◽  
Concrete Frame ◽  
Self Organizing

The paper presents the use of a self-organizing feature map (SOFM) for determining damage in reinforced concrete frames with shear walls. For this purpose, a concrete frame with a shear wall was subjected to nonlinear dynamic analysis. The SOFM was optimized using the genetic algorithm (GA) in order to determine the number of layers, number of nodes in the hidden layer, transfer function type, and learning algorithm. The obtained model was compared with linear regression (LR) and nonlinear regression (NonLR) models and also the radial basis function (RBF) of a neural network. It was concluded that the SOFM, when optimized with the GA, has more strength, flexibility, and accuracy.

scholarly journals Behaviour Factor of Ductile Code-Designed Reinforced Concrete Frames

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Massimiliano Ferraioli
Keyword(s):  
Reinforced Concrete ◽  
Nonlinear Response ◽  
Pushover Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Frame Structures ◽  
Risk Level ◽  
High Ductility ◽  
Concrete Frames ◽  
Reinforced Concrete Frames ◽  
Behaviour Factor

The current generation of seismic design codes is based on a linear elastic force-based approach that includes the nonlinear response of the structure implicitly through a response modification factor (named reduction factor R in American codes or behaviour factor q in European codes). However, the use of a prescribed behaviour factor that is constant for a given structural system may fail in providing structures with the same risk level. In this paper, the behaviour factor of reinforced concrete frame structures is estimated by means of nonlinear static (pushover) and nonlinear incremental dynamic analyses. For this purpose, regular reinforced concrete frames of three, five, seven, and nine storeys designed for high ductility class according to the European and Italian seismic codes are investigated, and realistic input ground motions are selected based on the design spectra. Verified analysis tools and refined structural models are used for nonlinear analysis. Overstrength, redundancy, and ductility response modification factors are estimated, and the effects of some parameters influencing the behaviour factor, including the number of bays and the number of storeys, are evaluated. The results are finally compared with those obtained from a previous paper for steel moment-resisting frames with the same geometry. According to the analysis results, the behaviour factors in the case of pushover analysis are significantly higher than those obtained in the case of nonlinear response history analysis. Thus, according to the pushover analysis, the behaviour factor provided by European and Italian standards seems highly conservative. On the contrary, the more refined nonlinear dynamic analysis shows that the code-prescribed value may be slightly nonconservative for middle-high-rise frame structures due to unfavourable premature collapse mechanisms based on column plastic hinging at the first storey. Thus, some modifications are desirable in local ductility criteria and/or structural detailing of high ductility columns to implicitly ensure that the recommended value of the behaviour factor is conservative.

Behavior of Framed Shearwalls Made of Corrugated Steel under Lateral Load Reversals

2000 ◽  
Vol 3 (3) ◽  
pp. 255-262 ◽  
Author(s):  
Y.L. Mo ◽  
S.F. Perng
Keyword(s):  
Reinforced Concrete ◽  
Seismic Behavior ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Reinforced Concrete Frames ◽  
Fiber Reinforced Plastic ◽  
Concrete Frame ◽  
Plastic Composites ◽  
Reinforced Plastic ◽  
Critical Regions

Reinforced concrete buildings with shearwalls are very efficient to resist earthquake disturbances. In general, reinforced concrete frames are governed by flexure and low-rise shearwalls are governed by shear. If a structure includes both frames and shearwalls, it is generally governed by shearwalls. However, the ductility of ordinary reinforced concrete framed shearwalls is very limited. The experiments on framed shearwalls made of corrugated steel was recently reported. It was found that the ductility of framed shearwalls can be greatly improved if the thickness of the corrugated steel wall is appropriate to the surrounding reinforced concrete frame. If the thickness of the corrugated steel wall is too large when compared to the surrounding frame, the ductility will be reduced. It is shown in this paper that the fiber-reinforced plastic composites can be used to strengthen the critical regions of the reinforced concrete frames, so that the seismic behavior (including ductility and energy dissipation capability) is greatly improved.

scholarly journals An Investigation on Sheeting Acting as a Diaphragm on a Reinforced Precast Concrete Frame

2020 ◽  
Author(s):  
Sergiu-Gheorghe Țere ◽  
Bogdan Hegheș ◽  
Horea Constantinescu
Keyword(s):  
Reinforced Concrete ◽  
Experimental Test ◽  
Precast Concrete ◽  
Steel Structures ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Reinforced Concrete Frames ◽  
Concrete Frame ◽  
Steel Sheets ◽  
Starting Point

It is well-known that for single-storey steel structures, the framework is greatly strengthened and stiffened following the attachment of the roof, floors and walls. The panels in the roofing, flooring and side cladding are also known as “shear diaphragms” by virtue of their resistance to being deformed into parallelograms. This has been verified by on-site practical experience of many structures and design provisions are available for structural engineers. Despite the fact that for single-storey structures, the corrugated steel sheets are the standard elements in constructing the envelopes, in what concerns the reinforced concrete frames there are no guidelines nor recommendations on how to consider the diaphragm effect in structural analysis. In order to better understand the interaction between the corrugated steel sheets and the reinforced concrete frame, a real precast reinforced concrete frame structure was built for experimental testing. The aim of the experimental test is to study the diaphragm effect for reinforced concrete structures and based on the results to identify the discrepancies identified compared to steel structures. The investigation attempts to provide a starting point for future research on the stressed skin design acting on reinforced concrete frames. At the end of the article conclusions are drawn based on the experience obtained during the experimental test.

scholarly journals FEM model for reinforced concrete frames loaded by seismic forces

2005 ◽  
Vol 32 (4) ◽  
pp. 283-317
Author(s):  
Dusan Kovacevic
Keyword(s):  
Reinforced Concrete ◽  
Nonlinear Behavior ◽  
Theoretical Research ◽  
Engineering Practice ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Fem Model ◽  
Reinforced Concrete Frames ◽  
Concrete Frame ◽  
Seismic Forces

Objective of the presented research is the formulation of one enough sophisticated and, for engineering practice, convenient finite element method (FEM) based numerical model for reinforced concrete frames loaded by seismic actions. For modeling of concrete and steel nonlinear behavior uniaxial constitutive rules are applied. The proposal for inclusion the frame joint deterioration, as well as, interaction of shear and flexural forces (inclined cracks effects), in this model, is given additionally. The results of few numerical tests (linear/nonlinear analysis of reinforced concrete frame loaded by three seismic actions) are given as an illustration of presented theoretical research.

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