Sharif Digital Repository

This paper evaluates the applicability of several concrete models to simulate the behavior of concrete elements under monotonic and cyclic loadings. Several robust constitutive models based on the combination of plasticity and continuum damage or plasticity and smeared crack approach are selected. The behavior of one concrete element is evaluated under different uniaxial compression, uniaxial tension, biaxial compression, biaxial tension, biaxial compression–tension, and triaxial compression loads. Then, the applicability of the concrete models is investigated for two flexural beams under cyclic loading. Five concrete models available in the versatile finite element-based software LS-DYNA... 

This paper focuses on the performance evaluation of several concrete models in reinforced concrete (RC) structures subjected to seismic loading. Despite many studies conducted on implementing different characteristics of concrete in constitutive models, there is an essential need for investigating the ability of these models in predicting the behavior of structures in seismic applications. In this paper, several developed plasticity-based constitutive models with the combination of fracture and continuum damage models are investigated for application in seismic loading conditions. Damage-based isotropic and anisotropic models and smeared cracking approach have been applied as complementary... 

This paper evaluates the applicability of several concrete models to simulate the behavior of concrete elements under monotonic and cyclic loadings. Several robust constitutive models based on the combination of plasticity and continuum damage or plasticity and smeared crack approach are selected. The behavior of one concrete element is evaluated under different uniaxial compression, uniaxial tension, biaxial compression, biaxial tension, biaxial compression–tension, and triaxial compression loads. Then, the applicability of the concrete models is investigated for two flexural beams under cyclic loading. Five concrete models available in the versatile finite element-based software LS-DYNA... 

The seismic performance of steel-plate concrete (SC) shear walls is numerically investigated for various SC wall geometrical shapes. Steel faceplates and infill concrete are two main components of SC walls; a full connection between steel and concrete is required for composite action. A comprehensive set of SC wall specimens with different cross-sectional shapes and geometrical properties were tested in the literature for evaluating their seismic behavior. The numerical responses of 17 tested SC walls, including rectangular, T-shaped, and flanged walls, isolated and coupled walls, with and without boundary elements and endplates, subjected to cyclic lateral loading and a wide range of axial... 

This paper proposes modeling recommendations, including constitutive model parameters for concrete and steel for nonlinear and macroscopic simulation of Composite Plate Shear Walls-Concrete Filled (C-PSW/CF) structures. Predictive equations are developed to determine the constitutive models of confined and unconfined concrete and steel faceplates, considering the buckling and fracture effects. A comprehensive database consisting of the test results of 37 C-PSW/CF specimens with and without endplates and boundary elements is collected and used to assess the required constitutive model parameters. Based on the validated macro model, predictive equations for backbone curves of unconfined and... 

This paper focuses on the application of a new shear link in moment-resisting frames by perforating the web at the mid-span of the beam. Typically, in moment-resisting frames the plastic hinges are formed at the end of the beams adjacent to the beam-column connections. Seismic codes specify a minimum length for the beams that are part of the moment-resisting frames to ensure those beams are flexure-critical, and their plastic hinges are formed at their ends. The use of shear fuse in the mid-span of seismic beams enables the designers to violate the minimum span-to-depth ratio requirement and facilitates the replacement of the damaged parts of the perforated web moment resisting frames... 

Steel-plate composite (SC) walls can be connected to a concrete basemat using a base plate and a set of anchors eccentric to the wall. The base plate can be separated into two parts so that the concrete of the wall and basemat is cohesive, and thus, the wall can be manufactured more easily and economically. Additionally, compression and shear demand are directly transferred from infill concrete to concrete basemat. Another change in the base plate connection of available tested walls involves transferring anchors to the bottom of faceplates. As a result of this modification, the base plate is removed from the force transmission chain, and the force is transferred directly from the wall to... 

A predictive equation is proposed for the axial-flexural strength of rectangular and flanged Composite Plate Shear Walls-Concrete Filled (C-PSW/CF), with and without endplates and boundary elements. The proposed equation is based on plastic stress distribution, adjusted by coefficients to account for influential design parameters. The adjustment coefficients are established by a regression analysis performed on the data developed using an extensive numerical parametric study. The continuum-based finite element model used for the simulations is first validated using the available test data. The effects of various design variables, including the aspect ratio, slenderness ratio, reinforcement... 

Electrical post insulators are important components of electrical substations since any type of failure in such insulators leads to the breakdown of the local network. Although the electrical substations are often in service condition, any horizontal excitation due to the earthquake, or any extreme event, may cause lateral deformation and damage to the post insulators. Hollow composite post insulators, a new and evolving technology, have a very complex mechanical behavior due to their materials and connections. To date, the design of such post insulators has been based on the limited test results available in the literature. Most of experiments have been conducted on small-scale specimens... 

Steel–concrete (SC) composite shear walls consist of infill concrete attached to two steel faceplates using tie rods and shear studs as connectors. Despite past efforts to validate the cyclic response of SC walls numerically, there is a lack of a comprehensive numerical study to propose a unique element modeling, steel and concrete material modeling, and contact definition to simulate the seismic response of all SC walls with different geometrical shapes and loading condition accurately. This paper numerically investigates the response of a wide variety of tested SC walls available in the literature. Ten SC wall specimens are modeled in the finite element-based software LS-DYNA and subjected... 

A new macro model is developed in the OpenSees environment to analyze SC shear walls efficiently. The proposed modeling technique benefits from higher accuracy in predicting the response of SC walls compared to similar macro models and lower computational costs. The proposed model is then used to predict the cyclic response of 12 rectangular SC wall specimens with and without boundary elements and end plates, tested under cyclic loading. The results confirm that the initial stiffness, peak strength, displacement at peak strength, and post-peak behavior predicted are in good agreement with test results. © 2023, Canadian Society for Civil Engineering  

Steel-plate concrete (SC) shear walls are used as the lateral-load resisting system in high-rise buildings as they can offer faster construction and reduced construction cost compared with their conventional reinforced concrete counterparts. This paper aims to predict the moment capacity of SC shear walls using the finite element analysis method and evaluate the current method by the AISC Seismic Provisions. Numerical parametric study of SC walls is used to develop a predictive equation for the moment capacity of such walls. The numerical analyses are then used to evaluate the method currently prescribed by the AISC Seismic Provisions. It is shown that the AISC design equation may not... 

Learning a foreign language encompasses a process of trial and error that can lead to the progression of the learner's interlanguage, meaning that the learners make use of their language knowledge that receives feedback and brings about progress through diagnosis of the problems and being corrected by the teacher. Therefore, there exists a need to analyze the underlying reasons causing the students to remain taciturn with a low willingness to communicate (WTC) during a language class. There has been much work done investigating the role of the learner's stable personal characteristics (traits) along with their situational changes at a specific time (states) that influence the student's... 

Using 3-D scanned data to analyze and extract pore network plays a vital role in investigation of porous media's characteristics. In this paper, a new simple method is developed to detect pores and throats for analyzing the connectivity and permeability of the network. This automated method utilizes some of the common and well-known image processing functions which are widely accessible by researchers and this has led to an easy algorithm implementation. In this method, after polishing and quality control of images, using city-block distance function and watershed segmentation algorithm, pores and throats are detected and 3-D network is produced. This method can also be applied on 2-D images... 

In this paper, we try to recognize and distinguish different groups of arrhythmia using novel features which have been obtained from the heart rate's phase space in recent years. For this purpose, we used Triangular Phase Space Mapping (TPSM) and Parabolic Phase Space Mapping (PPSM). For recognition, we used three groups of 15 subjects using the Physionet database (Arrhythmia, Congestive Heart Failure (CHF), and Atrial Fibrillation (AF)) with Normal Sinus Rhythm (NSR). The obtained features discriminate arrhythmia from NSR by p