دانشگاه تبریزنشریه مهندسی عمران و محیط زیست2008-791855S120250923A Numerical Method for Estimating the Dynamic Response of StructuresA Numerical Method for Estimating the Dynamic Response of Structures1191289010.22034/jcee.2021.41770.1963FAمهدیباباییگروه مهندسی عمران، دانشگاه بناب، آذربایجان شرقیمیثمجلیل خانیدانشکده فنی و مهندسی خوی، دانشگاه صنعتی ارومیهسمیهملاییدانشکده مهندسی عمران، دانشگاه بناب، آذربایجان شرقیJournal Article20200914A novel numerical method is proposed for computing the seismic response of linear and nonlinear systems. Single-degree-of-freedom (SDOF) and multi-degree-of-freedom (MDOF) systems are covered. The method is called load impulse method (LIM) because it uses the load impulse concept in its formulation. LIM is first extended for analyzing linear damped systems whose damping ratios are almost greater than 1% and nonlinear systems in general. To formulate LIM, the governing differential equation of motion (DEOM) is modified to have appropriate form for numerical integration. Then, it is integrated over time step using trapezoidal integration rule. Rearranging the obtained equation, the required relations are generated for computing seismic response of dynamic systems through simple iteration. The seismic response of several linear and nonlinear structural systems under dynamic loads is determined through the proposed LIM. A detailed comparison is then carried out between the results of LIM and those obtained from Duhamel integral, Newmark-β, and Wilson-θ methods. The results clearly show that the proposed LIM can robustly estimate the displacement, velocity, and acceleration time-histories of the dynamic systems within satisfactory computational cost.A novel numerical method is proposed for computing the seismic response of linear and nonlinear systems. Single-degree-of-freedom (SDOF) and multi-degree-of-freedom (MDOF) systems are covered. The method is called load impulse method (LIM) because it uses the load impulse concept in its formulation. LIM is first extended for analyzing linear damped systems whose damping ratios are almost greater than 1% and nonlinear systems in general. To formulate LIM, the governing differential equation of motion (DEOM) is modified to have appropriate form for numerical integration. Then, it is integrated over time step using trapezoidal integration rule. Rearranging the obtained equation, the required relations are generated for computing seismic response of dynamic systems through simple iteration. The seismic response of several linear and nonlinear structural systems under dynamic loads is determined through the proposed LIM. A detailed comparison is then carried out between the results of LIM and those obtained from Duhamel integral, Newmark-β, and Wilson-θ methods. The results clearly show that the proposed LIM can robustly estimate the displacement, velocity, and acceleration time-histories of the dynamic systems within satisfactory computational cost.https://ceej.tabrizu.ac.ir/article_12890_330f1d62a21a2121f4533577eebbcb47.pdfدانشگاه تبریزنشریه مهندسی عمران و محیط زیست2008-791855S120250923SCF distribution along the weld toe in tubular X-joints reinforced with doubler plates subjected to axial loading: Study of geometrical effects and design formulationSCF distribution along the weld toe in tubular X-joints reinforced with doubler plates subjected to axial loading: Study of geometrical effects and design formulation20341394310.22034/jcee.2021.48015.2073FAحمیداحمدیمرکز ملی مهندسی دریا و هیدرودینامیک، دانشگاه تزمنیا، استرالیامحمدحسنخوانین زادهدانشکده مهندسی عمران، دانشگاه تبریزJournal Article20210918Although tubular X-joints are quite common in offshore structural design and despite the crucial role of stress concentration factors (SCFs) in evaluating the fatigue performance of tubular joints, the SCF distribution in X-joints reinforced with doubler plates has not been investigated so far and no design equation is currently available to predict the distribution of chord-side SCFs along the weld toe of brace-to-chord intersection in this type of joint. In the present research, data extracted from the stress analysis of 81 finite element (FE) models, verified using available numerical results, was used to study the effects of geometrical parameters on the chord-side SCF distribution along the weld toe in doubler-plate reinforced tubular X-joints subjected to axial loading. Parametric FE study was followed by a set of nonlinear regression analyses to develop a new SCF parametric equation for the fatigue analysis and design of axially loaded tubular X-joints reinforced with doubler plates.Although tubular X-joints are quite common in offshore structural design and despite the crucial role of stress concentration factors (SCFs) in evaluating the fatigue performance of tubular joints, the SCF distribution in X-joints reinforced with doubler plates has not been investigated so far and no design equation is currently available to predict the distribution of chord-side SCFs along the weld toe of brace-to-chord intersection in this type of joint. In the present research, data extracted from the stress analysis of 81 finite element (FE) models, verified using available numerical results, was used to study the effects of geometrical parameters on the chord-side SCF distribution along the weld toe in doubler-plate reinforced tubular X-joints subjected to axial loading. Parametric FE study was followed by a set of nonlinear regression analyses to develop a new SCF parametric equation for the fatigue analysis and design of axially loaded tubular X-joints reinforced with doubler plates.https://ceej.tabrizu.ac.ir/article_13943_01bc8c2ebfb8b0342a70516e1b0b6fb5.pdfدانشگاه تبریزنشریه مهندسی عمران و محیط زیست2008-791855S120250923Laboratory Modeling of a Spread Footing on Sand Reinforced by Strips of Carbon Fiber ReinforcementLaboratory Modeling of a Spread Footing on Sand Reinforced by Strips of Carbon Fiber Reinforcement35451441210.22034/jcee.2022.50268.2116FAاحداوریاگروه مهندسی عمران، دانشکده فنی، دانشگاه محقق اردبیلیحمیدصادق پورگروه مهندسی عمران، دانشکده فنی، دانشگاه محقق اردبیلیاحمدفهمیگروه مهندسی عمران، دانشکده فنی، دانشگاه بنابJournal Article20220205The bearing capacity of a square footing on sand reinforced by carbon fiber reinforced polymer (CFRP) was investigated in the laboratory. A sand box with dimensions of 100×100×90cm was utilized as the test bed for experiments. A 20×20×2cm steel plate was employed to simulate the square footing. The sand was reinforced using 2cm width carbon fiber reinforced polymer (CFRP) strips with different numbers of strips, lengths, and depths. The effect of the horizontal distances between CFRP strips and chemical treatment of the interface of the CFRP and sand on the bearing capacity of the footing were investigated. The results of these tests indicated that with the same number of reinforcement strips, placing the reinforcement strips close to the center of the footing increases the bearing capacity of the foundation. The bearing capacity of the foundation on sand reinforced with a single layer CFRP strips could be improved by 50% in optimal condition. Epoxy resin treatment of the interface of the sand and CFRP strips increased the bearing capacity of the foundation by an additional 11%.The bearing capacity of a square footing on sand reinforced by carbon fiber reinforced polymer (CFRP) was investigated in the laboratory. A sand box with dimensions of 100×100×90cm was utilized as the test bed for experiments. A 20×20×2cm steel plate was employed to simulate the square footing. The sand was reinforced using 2cm width carbon fiber reinforced polymer (CFRP) strips with different numbers of strips, lengths, and depths. The effect of the horizontal distances between CFRP strips and chemical treatment of the interface of the CFRP and sand on the bearing capacity of the footing were investigated. The results of these tests indicated that with the same number of reinforcement strips, placing the reinforcement strips close to the center of the footing increases the bearing capacity of the foundation. The bearing capacity of the foundation on sand reinforced with a single layer CFRP strips could be improved by 50% in optimal condition. Epoxy resin treatment of the interface of the sand and CFRP strips increased the bearing capacity of the foundation by an additional 11%.https://ceej.tabrizu.ac.ir/article_14412_4ec7376a91fcde611120c93fb640135d.pdfدانشگاه تبریزنشریه مهندسی عمران و محیط زیست2008-791855S120250823Investigation of Dynamic Behavior of Stabilized Loose Sand by Microbially Induced Carbonate PrecipitationInvestigation of Dynamic Behavior of Stabilized Loose Sand by Microbially Induced Carbonate Precipitation46581546310.22034/jcee.2022.51666.2148FAحمیدنیکویهگروه مهندسی عمران ، واحد قزوین ، دانشگاه آزاد اسلامیمحمدآزادیگروه مهندسی عمران ، واحد قزوین ، دانشگاه آزاد اسلامیمجیدقیومیگروه مهندسی عمران و محیط زیست، دانشگاه نیوهمشایر، آمریکا / گروه مهندسی عمران ، واحد قزوین ، دانشگاه آزاد اسلامیJournal Article20220519Due to the increasing number of construction projects, various methods, including more environmentally friendly methods, are used to increase the strength and bearing capacity of soil. Bio-cementation method is one of the newest methods that uses bacteria to form calcium carbonate crystals to make high-strength metamorphic products. This process can stabilize soil without breaking the original structure. One of these processes, which are common in nature, is the microbiological deposition of calcium carbonate by enzymatic hydrolysis of urea. Due to the size of soil grains and the size of bacteria used in sediment production, these bacteria will be able to produce sediment in silty, clay and sandy soils that form a wide range of soils. In this research, the effect of microbially induced carbonate precipitation (MICP) on the cyclic properties (liquefaction resistance, secant shear modulus and damping ratio) of loose sand is investigated via performing cyclic triaxial tests. Results revealed that carbonate precipitation could significantly increase the liquefaction resistance of Kuhin sand. So that the required cycles to reach the liquefaction criteria was increased from 6 for unstabilized sand to 97 (at cyclic stress ratio (CSR) of 0.2) for 4 times grouted carbonate precipitated sand. Also, this value was increased to 127 for 6 times grouted carbonate precipitated sand. Moreover, test findings show that CSR has an important effect on liquefaction resistance such that, the number of cycles leading to liquefaction decreased from 127 to 46 with the increase of CSR from 0.2 to 0.3 for 6 times grouted carbonate precipitated sand. Due to the carbonate precipitation, the secant shear modulus of sand increased by up to 67%, and also the damping ratio of sand increased by up to 50%.Due to the increasing number of construction projects, various methods, including more environmentally friendly methods, are used to increase the strength and bearing capacity of soil. Bio-cementation method is one of the newest methods that uses bacteria to form calcium carbonate crystals to make high-strength metamorphic products. This process can stabilize soil without breaking the original structure. One of these processes, which are common in nature, is the microbiological deposition of calcium carbonate by enzymatic hydrolysis of urea. Due to the size of soil grains and the size of bacteria used in sediment production, these bacteria will be able to produce sediment in silty, clay and sandy soils that form a wide range of soils. In this research, the effect of microbially induced carbonate precipitation (MICP) on the cyclic properties (liquefaction resistance, secant shear modulus and damping ratio) of loose sand is investigated via performing cyclic triaxial tests. Results revealed that carbonate precipitation could significantly increase the liquefaction resistance of Kuhin sand. So that the required cycles to reach the liquefaction criteria was increased from 6 for unstabilized sand to 97 (at cyclic stress ratio (CSR) of 0.2) for 4 times grouted carbonate precipitated sand. Also, this value was increased to 127 for 6 times grouted carbonate precipitated sand. Moreover, test findings show that CSR has an important effect on liquefaction resistance such that, the number of cycles leading to liquefaction decreased from 127 to 46 with the increase of CSR from 0.2 to 0.3 for 6 times grouted carbonate precipitated sand. Due to the carbonate precipitation, the secant shear modulus of sand increased by up to 67%, and also the damping ratio of sand increased by up to 50%.https://ceej.tabrizu.ac.ir/article_15463_2fb8d43f43f145bd49f3ee1c7873694f.pdfدانشگاه تبریزنشریه مهندسی عمران و محیط زیست2008-791855S120250923Numerical Simulation of Sediment Transport to Investigate Riverbed Changes Considering the Effect of Dam Construction (Case Study: Saqqez River)Numerical Simulation of Sediment Transport to Investigate Riverbed Changes Considering the Effect of Dam Construction (Case Study: Saqqez River)59751917710.22034/ceej.2025.64073.2390FAسیدداناپریزادیگروه مهندسی عمران، دانشکده مهندسی، دانشگاه کردستان، سنندجمحسنایثاریگروه مهندسی عمران، دانشکده مهندسی، دانشگاه کردستان، سنندجاحسانجعفری ندوشنگروه مهندسی عمران، دانشکده مهندسی، دانشگاه کردستان، سنندجJournal Article20241019The study of sediment transport phenomena in rivers is critically essential. Human interventions, such as constructing hydraulic structures across river cross-sections, disrupt the natural sediment transport cycle, which affects ecological processes and alters habitat conditions. The presence of an upstream dam results in the accumulation of sediment materials behind the dam wall, significantly reducing the suspended sediment load in the river. This study investigates changes in parameters such as sediment concentration in the flow and variations in the gravel riverbed due to the upstream dam. Additionally, the study examines the impact of temperature changes and the accumulation of floating debris upstream of bridge piers on the riverbed. This research employs the HEC-RAS hydrodynamic model for quasi-unsteady daily flow and utilizes Yang's total sediment load equation. The results demonstrate that constructing an upstream dam leads to increased erosion in cross-sections that previously experienced sediment deposition in the absence of the dam. The peak flow sediment discharge entering the study area for the no-dam and dam scenarios was 30640.83 tons/day and 9964.063 tons/day, respectively, indicating a 67.48% reduction in sediment discharge due to the upstream dam. The outgoing sediment discharge from the study area was 12333.93 tons/day without the dam and 7,723.62 tons/day with the dam, showing a reduction of approximately 59.75% and 22.48% compared to the upstream sediment discharge.The study of sediment transport phenomena in rivers is critically essential. Human interventions, such as constructing hydraulic structures across river cross-sections, disrupt the natural sediment transport cycle, which affects ecological processes and alters habitat conditions. The presence of an upstream dam results in the accumulation of sediment materials behind the dam wall, significantly reducing the suspended sediment load in the river. This study investigates changes in parameters such as sediment concentration in the flow and variations in the gravel riverbed due to the upstream dam. Additionally, the study examines the impact of temperature changes and the accumulation of floating debris upstream of bridge piers on the riverbed. This research employs the HEC-RAS hydrodynamic model for quasi-unsteady daily flow and utilizes Yang's total sediment load equation. The results demonstrate that constructing an upstream dam leads to increased erosion in cross-sections that previously experienced sediment deposition in the absence of the dam. The peak flow sediment discharge entering the study area for the no-dam and dam scenarios was 30640.83 tons/day and 9964.063 tons/day, respectively, indicating a 67.48% reduction in sediment discharge due to the upstream dam. The outgoing sediment discharge from the study area was 12333.93 tons/day without the dam and 7,723.62 tons/day with the dam, showing a reduction of approximately 59.75% and 22.48% compared to the upstream sediment discharge.https://ceej.tabrizu.ac.ir/article_19177_e04ec1aa8176472737a5fa697d43f944.pdfدانشگاه تبریزنشریه مهندسی عمران و محیط زیست2008-791855S120250823Optimizing Water Allocation in a Changing Climate Utilizing WEAP and SSP5.85 Scenarios- A Case Study: Keshan Chai basinOptimizing Water Allocation in a Changing Climate Utilizing WEAP and SSP5.85 Scenarios- A Case Study: Keshan Chai basin76992014710.22034/ceej.2025.66162.2420FAفرحنازخرم آبادیدانشجوی دکترای آب و هواشناسی، دانشگاه اصفهانبهادرفاتحی نوبریانگروه مهندسی عمران، دانشگاه آزاد اسلامی واحد جلفاسینافرد مرادی نیادانشکده فنی، گروه مهندسی عمران، دانشگاه آزاد تبریزJournal Article20250301This study investigates the potential effects of the Isar Dam on the water resources of a specific basin, considering the growing concern of climate change. This research comprehensively assesses the impacts of climate change on the Keshan Chai basin by integrating advanced methods such as the WEAP model, the SSP5.85 scenario of the IPCC Sixth Assessment Report, and Landsat satellite imagery an analysis of historical data reveals significant fluctuations in water flow within the Ravasjan River, likely caused by repeated occurrences of floods and droughts. To address these variations and ensure a more stable water supply, the Isar Dam is projected to deliver regulated water for various purposes: 14 million cubic meters annually for drinking water, 35 million cubic meters annually for agriculture, and 4 million cubic meters annually for environmental needs. Climate change simulations project a 5% increase in annual precipitation for the forecast period (2025-2065) compared to the observation period (1990-2020), raising concerns about increased flooding in the region. The study also identifies three distinct climatic types based on monthly precipitation distribution. The minimum environmental flow requirement is estimated at 5.0 cubic meters per second monthly. Scenario-based water demand modeling shows that in Scenario 1, 92% of Ozghan’s demand and 47% of the development networks are met in 70% of cases, with full satisfaction in 30%. Scenario 2 achieves 90% and 45% in 70% of cases, fully met in 25%. Scenario 3 meets 77% and 38% in 70% of cases, with 23% full satisfaction. Precipitation variability between 2011 and 2020 has created challenges for water management. Principal component analysis indicates 62.19% and 15.98% of precipitation variance are explained.This study investigates the potential effects of the Isar Dam on the water resources of a specific basin, considering the growing concern of climate change. This research comprehensively assesses the impacts of climate change on the Keshan Chai basin by integrating advanced methods such as the WEAP model, the SSP5.85 scenario of the IPCC Sixth Assessment Report, and Landsat satellite imagery an analysis of historical data reveals significant fluctuations in water flow within the Ravasjan River, likely caused by repeated occurrences of floods and droughts. To address these variations and ensure a more stable water supply, the Isar Dam is projected to deliver regulated water for various purposes: 14 million cubic meters annually for drinking water, 35 million cubic meters annually for agriculture, and 4 million cubic meters annually for environmental needs. Climate change simulations project a 5% increase in annual precipitation for the forecast period (2025-2065) compared to the observation period (1990-2020), raising concerns about increased flooding in the region. The study also identifies three distinct climatic types based on monthly precipitation distribution. The minimum environmental flow requirement is estimated at 5.0 cubic meters per second monthly. Scenario-based water demand modeling shows that in Scenario 1, 92% of Ozghan’s demand and 47% of the development networks are met in 70% of cases, with full satisfaction in 30%. Scenario 2 achieves 90% and 45% in 70% of cases, fully met in 25%. Scenario 3 meets 77% and 38% in 70% of cases, with 23% full satisfaction. Precipitation variability between 2011 and 2020 has created challenges for water management. Principal component analysis indicates 62.19% and 15.98% of precipitation variance are explained.https://ceej.tabrizu.ac.ir/article_20147_4d8aa54016348c5a5b5743fcbe8cea69.pdfدانشگاه تبریزنشریه مهندسی عمران و محیط زیست2008-791855S120250923Optimization of Large-Scale Frame Structures by Means of Improved Artificial Rabbits Optimization AlgorithmOptimization of Large-Scale Frame Structures by Means of Improved Artificial Rabbits Optimization Algorithm1141002033010.22034/ceej.2025.64646.2399FAسیده لادنسیداسکوییگروه مهندسی عمران ، واحد مهاباد ، دانشگاه آزاد اسلامیرضاسجودی زادهگروه مهندسی عمران ، واحد مهاباد ، دانشگاه آزاد اسلامیرضامیلانچیانگروه مهندسی عمران ، واحد مهاباد ، دانشگاه آزاد اسلامیهادیعزیزیانگروه مهندسی عمران ، واحد مهاباد ، دانشگاه آزاد اسلامیJournal Article20241123With the advancement of intelligent computing systems in recent decades, the optimization process of structures has been significantly improved. These systems provide accurate and fast analysis of complex structures and enable engineers to use more advanced and effective methods in the design and optimization of structures. This ability enables them to obtain optimal solutions in the shortest possible time by analyzing large and complex data. Thus, using intelligent computing systems accelerates and improves the accuracy of structural optimization. The main concern of this study is to investigate the applicability of the Artificial Rabbits Optimization (ARO) algorithm, as one of the recently developed metaheuristic algorithms, in the design optimization of large-scale frame structures. For numerical purposes, three frame structures are selected with different characteristics, an 8-story, single bay frame structure; a 15-story, 3-bay benchmark frame structure; and a 24-story, 3-bay frame structure. In order to improve the overall computational performance of the standard ARO algorithm, an enhanced version of this algorithm is proposed as I-ARO by using the Diagonal Linear Uniform (DLU) initialization process instead of the conventional Brownian random initialization scheme. By comparing the results of I-ARO with those of other approaches in the literature, it can be concluded that the DLU process significantly upgrades the optimization capability of the standard ARO algorithm, such that the improved algorithm provides lower structural weight in the considered design examples.With the advancement of intelligent computing systems in recent decades, the optimization process of structures has been significantly improved. These systems provide accurate and fast analysis of complex structures and enable engineers to use more advanced and effective methods in the design and optimization of structures. This ability enables them to obtain optimal solutions in the shortest possible time by analyzing large and complex data. Thus, using intelligent computing systems accelerates and improves the accuracy of structural optimization. The main concern of this study is to investigate the applicability of the Artificial Rabbits Optimization (ARO) algorithm, as one of the recently developed metaheuristic algorithms, in the design optimization of large-scale frame structures. For numerical purposes, three frame structures are selected with different characteristics, an 8-story, single bay frame structure; a 15-story, 3-bay benchmark frame structure; and a 24-story, 3-bay frame structure. In order to improve the overall computational performance of the standard ARO algorithm, an enhanced version of this algorithm is proposed as I-ARO by using the Diagonal Linear Uniform (DLU) initialization process instead of the conventional Brownian random initialization scheme. By comparing the results of I-ARO with those of other approaches in the literature, it can be concluded that the DLU process significantly upgrades the optimization capability of the standard ARO algorithm, such that the improved algorithm provides lower structural weight in the considered design examples.https://ceej.tabrizu.ac.ir/article_20330_75b401af5fc18a21444855fa680854be.pdf