H. Naderpour

Semnan University · Faculty of Civil Engineering

Due to high strength and ductility, concrete filled steel tube columns have been highly regarded in recent decades and many experimental studies have been carried out in predicting the strength of these columns. Increase in compressive strength of concrete core by the lateral confinement provided by steel tube and delay of the steel local buckling...

In this study, a new mathematical model is developed composed of two parts, including harmonic and polynomial expressions for simulating the dominant velocity pulse of near fault ground motions. Based on a proposed velocity function, the corresponding expressions for the ground acceleration and displacement time histories are also derived. The prop...

Seismic response of structures in the vicinity of causative earthquake faults can be significantly different than those observed further away from the seismic source. In the near fault zone, ground motions are significantly influenced by the rupture mechanism and slip direction relative to the site and by the permanent ground displacement at the si...

Composite Reinforced Concrete (RC) wall system refers to a cantilever composite wall, where steel or Fiber Reinforced Polymer (FRP) components are embedded in or attached to an RC wall. The results of an analytical and parametric study on the effectiveness of using externally bonded steel plates and FRP sheets on RC shear walls as a retrofit techni...

Strengthening and retrofitting of concrete columns by wrapping and bonding FRP sheets has become an efficient technique in recent years. Considerable investigations have been carried out in the field of FRP-confined concrete and there are many proposed models that predict the compressive strength which are developed empirically by either doing regr...

The widespread application of reinforced concrete structures in different environmental conditions has underscored the need for effective maintenance and repair strategies. These structures offer numerous advantages, but are not impervious to the deleterious effects of chemical deterioration. The outcomes of this research hold significant implicati...

This article presents a novel approach to estimate the flexural capacity of reinforced concrete-filled composite plate shear walls using an optimized computational intelligence model. The proposed model was developed and validated based on 47 laboratory data points and the Transit Search (TS) optimization algorithm. Using 80% of the experimental da...

This study, unlike prior studies, utilizes a smartphone camera as a high-speed camera for output-only operational modal analysis by using video measurement and advanced computer vision algorithms. Besides, the accelerometer sensors of the three smartphones collect the acceleration data. In contrast to recent research, this study has been conducted...

To control tunneling risk, the prediction of the surface settlement rate induced by shield tunneling using earth pressure balance plays a crucial role. To achieve this, ten independent variables were identified that can affect the amount of settlement. The nonlinear relationship between maximum ground surface settlements and ten influential indepen...

A critical zone is formed at the junction of the lower concrete and upper steel sections in mixed concrete/steel structures in terms of gravity and lateral loads caused by the support reactions of the steel frame. There are two common approaches to transition from concrete section to steel one in this critical zone: the first is the direct pin conn...

These codes are extracted from a novel meta-heuristic optimization algorithm namely ILA, which is based on IbI theory. The algorithm has been published in 2023. In order to evaluate the capability of the proposed algorithm, 73 constrained and unconstrained problems are considered and the results have been compared with 19 well- known optimization a...

Large displacement of structures observed during seismic excitations may lead to collisions between two adjacent, insufficiently-separated buildings and may result in major damages of both of them. In many building codes, appropriate equations or approximately recommended distances between structures in order to avoid pounding hazard have been intr...

The human mind is a complex biological member with unique abilities. Today, even the most advanced computers cannot do all the brain's calculations in one second. The mind is teachable, and its logic will change based on what it has learned over time. This behavior will be the base of a theory presented in this article, named Incomprehensible but I...

The application of fiber-reinforced polymer bars is rapidly rising in concrete structures because of corrosion resistance and high tensile strength. By contrast, concrete structures reinforced with Fiber-Reinforced Polymer (FRP) bars illustrate less ductility and brittle failure without warning than reinforced concrete structures with conventional...

Single fiber pull-out and fiber-matrix interfacial interaction play an essential role in understanding the mechanical behavior of fiber-reinforced cementitious composites. The present study introduces a computational model for predicting the maximum fiber pull-out force and corresponding bond slip. An extensive literature survey was performed to cr...

A new model-free output-only signal processing-based damage detection procedure was carried out in this paper. First of all, a finite element model as the representative of reinforced concrete (RC) frames was constructed and subjected to a specific loading protocol in OpenSees. The protocol consisted of 9 consequent different near-fault fling-step...

Nowadays, maintenance and health monitoring of structures and infrastructures of the country are the top priority of engineers. Therefore, acceleration sensors, which are installed on the bridge are used to extract the bridge's modal response, and even the latest studies have shown that sensors that have been attached to the car's chassis can recor...

Operational modal analysis typically requires the physical attachment of a sensor to measure the structure vibration. As a non-contact method, digital cameras are relatively inexpensive, fast, and provide high spatial resolution results. The aim of this study is to identify the dynamic parameters of structures (frequency and damping ratio) by using...

A building that contains two different lateral resisting systems in its height exampling a Reinforced Concrete (RC) moment frame for the lower and a steel moment frame for the upper floors, respectively is called a mixed concrete/steel building. At the intersection of the two parts of RC and steel, there is a floor called a transition story made of...

A building that contains two different lateral resisting systems in its height exampling a Reinforced Concrete (RC) moment frame for the lower and a steel moment frame for the upper floors, respectively is called a mixed concrete/steel building. At the intersection of the two parts of RC and steel, there is a floor called a transition story made of...

The compressive capacity of the column is one of the key parameters in the design. The importance of such structural members and their performance under load conditions are very effective in the overall behavior of the structure, and its failure can lead to the collapse of the entire structure. Therefore, determining the capacity of columns is cons...

Since post-mainshock events following a major earthquake are likely to occur, it is imperative to have an understanding of the functionality status of mainshock-damaged bridges to make more informed decisions. This paper examines the post-earthquake operability of a typical highway bridge class in reference to the time-varying nature of aftershock...

Seismic resilience is the residual capacity of a damaged system for recovering and sustaining an acceptable level of performance as a consequence of a seismic event. Firstly, this paper summarizes the current calculation framework of seismic resilience using fragility analyses. After that, a new metric based on vulnerability analyses is developed t...

A major cause of local to total damages is related to structural pounding in a large number of past earthquakes. In general, these collisions take place as a result of differences in the dynamic characteristics of the colliding structures. To acquire a better perception of the behavior of structures, in this paper, three structures featuring differ...

Due to the adverse effects of local corrosion of bars on the behavior of reinforced concrete structures, this problem has been investigated by many experimental studies. Reducing the cross-sectional area of steel bars due to corrosion diminishes the bearing capacity. On the other hand, weakening the interaction characteristics between bar and concr...

Do you know Transit? Watch this video.

Seismic resilience is the residual capacity of a damaged system for recovering and sustaining an acceptable level of performance as a consequence of a seismic event. Firstly, this paper summarizes the current calculation framework of seismic resilience using fragility analyses. After that, a new metric based on vulnerability analyses is developed t...

This paper addresses geometrically nonlinear topology optimization using IsoGeometric Analysis (IGA) and Level Set Method (LSM) under plane stress assumptions. The IGA is employed to solve governing equations and accurately describe geometric modeling. The pointwise gradient-based sensitivity analysis is applied to derive the normal velocity of the...

The methods for preventing earthquake-induced structural pounding between two adjacent buildings include ensuring a sufficient separation distance between them or decreasing their relative displacement during seismic excitation. Some equations or even specific values of such gap sizes between two buildings have been introduced so as to avoid collis...

This article presents a neuro-fuzzy model to predict the resilience index of reinforced concrete moment frames of school buildings. For this purpose, several parameters, including the total height to total width ratio, period, spectral acceleration, peak ground velocity, the effective duration of the earthquake, and distance from the fault, have be...

Nonlinear dynamic analysis (NDA) needs a large computation time and volume. In this study, an innovative method is proposed based on utilizing discrete wavelet transform to reduce the computational volume and time of NDA. For this purpose, several far- and near-field ground motion records are selected and decomposed into three levels using Wavelet...

MATLAB Codes for Constrained and Unconstrained Problems based on a novel astrophysics-inspired meta-heuristic optimization algorithm, namely Transit Search (TS)

In this article, a novel astrophysics-inspired meta-heuristic optimization algorithm, namely Transit Search (TS) is proposed based on a famous exoplanet exploration method. More than 3800 planets have been detected using transit technique by the database of the space telescopes. Transit is a method that has shown more potential than the second well...

This research investigated how cement content, the water to cement (W/C) ratio, and the sand to aggregate (S/A) ratio may affect Roller-Compacted Concrete (RCC) mechanical properties. Results were obtained through experimental tests and response surface methodology (RSM) analysis. Two cement content, three W/C ratios, and three S/A ratios were impl...

https://www.mdpi.com/journal/sustainability/special_issues/building_materials_construction

This article aims to present the results of an investigation on detection and quantification of damage location and severity for steel structures using wavelet packet transform for denoising the initial signals, in combination with a peak picking technique, to capture the modal parameters of the structures. In the peak picking technique, as an exte...

To provide lateral resistance in structures as well as buildings, there are some types of structural systems such as shear walls. The utilization of lateral loads occurs on a plate on the wall's vertical dimension. Conventionally, these sorts of loads are transferred to the wall collectors. There is a significant resistance between concrete shear w...

A major cause of local to total damages is related to structural pounding in a large number of past earthquakes. In general, these collisions take place as a result of differences in the dynamic characteristics of the colliding structures. To acquire a better perception of the behavior of structures, in this paper, three structures featuring differ...

This paper addresses geometrically nonlinear topology optimization using IsoGeometric Analysis (IGA) and Level Set Method (LSM) under plane stress assumptions. The IGA is employed to solve governing equations and accurately describe geometric modeling. The pointwise gradient-based sensitivity analysis is applied to derive the normal velocity of the...

The study of earthquake ground motion is a key issue in the field of earthquake resistance. Near-fault ground motions are more severe than other ground motions recorded that occur in the Far- Fault because proximity to the seismic source does not allow considerable attenuation of ground motion. Near-fault ground motion is characterized by its long-...

This article aims to utilize IsoGeometric Analysis (IGA) and Level Set Method (LSM) for topology optimization of elastoplastic plane stress problems. The IGA is employed to model geometries and calculate unknown displacements by satisfying equilibrium for materially-nonlinear problems. The von Mises elastoplastic material behavior model with and wi...

In this article, new efficient methods are presented to classify failure modes in reinforced concrete columns. For this purpose, machine learning techniques were utilized with consideration of laboratory datasets collected from the literature. Two different approaches, including decision tree and artificial neural network, have been studied to dete...

The aim of the present paper is to verify the effectiveness of the artificial neural network (ANN) in predicting the peak lateral displacement of multi-story building during earthquakes, based on the peak ground acceleration (PGA) and building parameters. For the purpose of the study, the lumped-mass multi-degree-of-freedom structural model and dif...

In this paper, three different damage indexes were used to detect nonlinear damages in two adjacent Reinforced Concrete (RC) structures considering pounding effects. 2-, 4- and 8-story benchmark RC Moment Resisting Frames (MRFs) were selected for this purpose with 60%, 75%, and 100% of minimum separation distance and also without any in-between sep...

One of the most important parameters used in the frame design process is the fundamental period. Numerous relationships are provided in the regulations and articles to determine the above parameter. However, due to the lack of optimal accuracy of existing equations, researchers are trying to improve them and increase the computational accuracy of t...

The shape memory alloys (SMAs) are special materials able to withstand large non-elastic deformations regaining their original form by removing stress. High fatigue strength and proper resistance to corrosive agents are the specific characteristics of these alloys. This article explores the SMA and carbon fiber reinforced polymer (CFRP) at designat...

Even small torsional moments can produce significant stress in beams and alter the behavior of the entire structure. Although many studies on the torsional behavior of reinforced concrete (RC) beams strengthened with fiber-reinforced polymer (FRP) sheets, there are still some uncertainties regarding the behavior of these beams under combined torsio...

Human factors are one of the main reasons for structural damage as they decrease the bearing capacity and also lead to an inaccurate estimation of the structure. Previous studies show that the use of CFRP in the damaged structures can significantly increase their bending and shear capacity. This study examines the capacity and cracks distribution i...

Uncertainties in seismic demand and structural capacity create conservatism in the acceptance criteria of structural performance levels. This conservatism can be reduced and designs optimised by considering and reducing uncertainties. In seismic rehabilitation, a secondary system added to an existing structure has probabilistic parameters that can...

In recent years, the use of composite rebars in reinforced concrete structures has received much attention due to its high corrosion resistance, significant tensile strength, and appropriate non-magnetization characteristics. Due to the lower modulus of elasticity of composite rebars than steel rebars, concrete beams reinforced with composite rebar...

In this article, seismic fragility of a base-isolated special Reinforced Concrete (RC) moment frame is investigated under near-fault pulse-type ground motion records. The vulnerability of the displacement-dominated performance of isolator devices to a likely vibration resonance caused by such records is the focus of the study. For this purpose, Lea...

In reinforced concrete (RC) moment frames, the performance of the whole structure to provide a suitable strength against lateral loads depends on the behavior of each structural element. Therefore, the capacity of such members plays a vital role in the final response of RC buildings. However, the nonlinear nature of complex materials like concrete...

The purpose of this paper is to present an innovative equation to predict the moment capacity of spirally reinforced concrete columns with high accuracy using a combination of neural network and metaheuristic optimization algorithms. To this end, a large experimental database has been gathered to train a neural network with seven independent parame...

Soft computing (SC), due to its high abilities to solve the complex problems with uncertainty and multiple parameters, has been widely investigated and used, especially in structural engineering. They have successfully estimated the capacity of structural reinforced concrete (RC) members and determined the properties of concrete. There are so many...

In shear wall-based buildings, locating the shear wall in plan has an important role in the resistance of seismic loading. In this article, the minimum torsion is considered as one of the main goals for optimal layout of shear walls, unlike the common method that accepts a certain torsion limit. The method presented is in accordance with the princi...

This study aims to present an approach to investigate the reliability levels of reinforced concrete (RC) columns confined by Fiber Reinforced Polymers (FRP) subjected to concentric loading. First, the statistical properties of random variables such as model error, FRP strain efficiency factor (FSE factor) and axial resistance of columns are investi...

Peak shear strength estimation of RC shear walls is one of the influential parameters on the design of RC shear walls. Considering all models and equations provided by researchers and building design codes, it is still not possible to estimate the peak shear strength of shear walls with high level of accuracy. Therefore, the authors proposed three...

Using high-strength reinforcements (HSRs) has several benefits in terms of financial and execution considerations. However, possible effects of HSR application on structural behavior such as ductility, energy dissipation, and damage process are not fully known for the researchers. In this study, firstly the HSR effects on the cyclic behavior, crack...

Seismic excitations may lead to collisions between adjacent civil engineering structures, causing major damage. In this paper, an effective equation for calculating the gap size index is proposed so as to provide the optimum separation distance preventing structural pounding during different earthquakes. Evaluation of the best prediction of the req...

Previous earthquakes have shown that for structures that experienced a significant ground motion with only minor damage, there is a likelihood of severe damage or complete collapse during the aftershocks. Due to the importance of such seismic sequences in structural engineering investigations, in this study, the vulnerability of Reinforced Concrete...

The effect of mainshock-aftershock (MS-AS) sequences on seismic performance of ordinary reinforced concrete (RC) moment frames (ORCFs) is studied by considering various levels of mainshock damage represented by maximum inter-story drift (MID) parameter. Incremental dynamic analysis (IDA) is performed to extract collapse capacity of structures under...

In this article, the discrete wavelet transform (DWT) has been used to construct the wavelet response spectrum analysis (WRSA) of structures in the linear elastic zone. For this purpose, the elastic response spectra of different single degree of freedom (SDOF) systems are studied for different beam-to-column stiffness ratios. Initially, using the D...

The effects of high-strength steel (HSS) on the damage indices (DIs) of four special moment frames and three beam– column connection (BCC) specimens under cyclical loading were experimentally studied. The specimens with HSS rebars (with yield strengths of 500 MPa and 580 MPa) were designed and constructed based on the special seismic provisions of...

Shear walls are the type of structural systems that provide the lateral resistance to a building or structure. Lateral loads are applied on one plate and along the vertical dimension of the wall. These type of loads are usually transmitted to the wall collectors. Concrete shear walls have a considerable resistance to lateral seismic loading. Model...

In this article, the effect of mainshock-aftershock sequences on the seismic performance of ordinary reinforced concrete frames (ORCFs) retrofitted by fiber reinforced polymers (FRPs) is studied. Various mainshock damage levels are used to precede aftershocks that are incrementally scaled to drive the studied structures into the collapse state. The...

Fi­bre Re­in­forced Poly­mer (FRP) bars have great po­ten­tial for the strength­en­ing of the ex­ist­ing build­ings. They also can be used as a suit­able re­place­ment for steel bars. There­fore, the struc­tural be­hav­ior and pre­dict­ing the strength of the con­structed el­e­ments by this type of ma­te­r­ial is an im­por­tant is­sue. How­ever, th...

Computational intelligence (CI) is a powerful approach to determine the response values of complex systems. Despite their benefits, the way to reach the solution in these approaches is difficult and cannot be expressed in a clear and simple formulation. In recent years, some methods have been proposed to provide simple and efficient mathematical fo...

In this article, three bio-inspired predictive models are proposed with the aim of estimating the shear capacity of reinforced concrete (RC) beams having steel stirrups. For this purpose, 194 experimental tests of this type of RC beams were gathered from the literature. Then, the structures of the artificial neural network models are trained and va...

Seismic isolation systems, especially friction pendulum bearings (FPBs), are used as ideal seismic protection strategies in performance-based design. Furthermore, FPBs can increase the functionality of buildings by minimizing interruption of use of the facility (e.g., operational performance level) and reducing seismic demands on the structural and...

Bridges are the indispensable arterial transport of a country. Iran, as a vast country, needs to develop a variety of road transportation inside and outside cities. Accelerating construction procedures and controlling costs are project management requirements. Risks, in many cases, disrupt the progress of the projects and impose costs on the projec...

The bond strength among the concrete and reinforced bars is one of the most important factors in designing the reinforced concrete structures. One of the serious problems encountered by utilization of steel‐reinforcement bars is corrosion when exposed to different environments. Glass fiber‐reinforced polymers (GFRPs) are known as a solution to prev...

In this study, a new computational approach for determination of the bond strength of Fibre Reinforced Polymer (FRP) strip-to-concrete joints is presented based on Adaptive Neuro-Fuzzy Inference System (ANFIS). For this purpose, 150 experimental data were gathered from the literature. The number of 120 data were used to train the system, and the ot...

Although using high-strength reinforcements (HSRs) have economical and execution benefits, their possible negative effects on the performance of structures such as ductility, energy dissipation, and damage process caused them to be restricted by building codes in seismic areas. In this research, the HSR effects on the cyclic behavior, cracking proc...

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