https://civil-ferdowsi.um.ac.ir/ Ferdowsi Civil Engineering en daily 1 Sun, 23 Aug 2026 00:00:00 +0330 Sun, 23 Aug 2026 00:00:00 +0330 https://civil-ferdowsi.um.ac.ir/article_47941.html Unsustainable water resource management, especially in stressed basins, is a concrete example of the tragedy of the commons, where prioritizing short-term economics pushes the performance of natural systems to breaking points. The emergence of competition from this development creates irreversible conditions for water resources in the long term. The Zayandeh-Rud basin serves as a common-pool resource for stakeholder competition and water reallocation. Therefore, in this study, with a theoretical–quantitative approach the flow change process was first analyzed, then the dynamic competition and exploitation in the Zayandeh-Rud basin was simulated using the WEAP model. In the final step, the socio-ecological status of the basin was assessed using the Water Ecological Carrying Capacity Index (WECCI) framework and Hardin's perspective in the form of the Pressure-Support-Status (PSS) structure. The results on an annual scale and in three five-year periods (2006-2010), (2011-2015) and (2016-2021) show that the balance between pressure and support has gradually deteriorated in the three time periods and has changed from a carrying capacity state to an overload state (increasing from 0.3 to 1.1 and then 3.8). At the same time, the WECCI has fallen to the “poor” and “extremely poor” range in most years. The results indicate that in recent years, especially with the increase in abstractions and the growth of demand, the basin has exceeded its natural and social capacity and has revealed the occurrence of a tragedy of the common resources. https://civil-ferdowsi.um.ac.ir/article_47975.html In this study, after identifying the factors and parameters affecting the duration of construction projects, the system thinking approach and system dynamics method are used to find the root causes, relationships and feedback between the factors. Library studies were used to identify the factors affecting the duration of the projects and Delphi interviews with 22 experts were used to improve and supplement these factors. Then, a conceptual model based on causal loops is presented to better understanding of the relationships between variables. Afterwards, using the approach governing the system dynamics method, a flow diagram is compiled to better understand and learn and also to more dynamic analysis of the research problem. The accuracy of the accumulation flow model has been measured with some tests, including reviewing and evaluating the behavior and structure of the model, and also four main scenarios were formulated for implementing different executive policies. Based on the results, the behavior and performance of the model have been evaluated and analyzed. The results obtained from the evaluations confirm the correct performance of the proposed model. Simulation results across four scenarios demonstrated that the most effective levers for project acceleration are the minimization of owner-driven scope/method changes and the strategic investment in human resource development (training and fair compensation), which significantly mitigate project delays by improving system efficiency. It is hoped that the understanding gained from this learning system will provide the necessary basis for making better and more efficient decisions in the field of project time. https://civil-ferdowsi.um.ac.ir/article_47985.html In this study, the hydraulic performance of a semi-circular rotary gate, along with a gradual transition with three different lengths in a rectangular canal, was investigated. Experiments were conducted using various flow rates, upstream water depths, and gate opening angles. The interaction of the flow with the edge of the rotary gate causes flow division and lateral variations in the water surface. Results showed that these variations decrease as the gate opening angle increases, with the highest instability occurring at an angle of 35 degrees and the lowest at 85 degrees. The velocity and discharge on the right side of the gate were higher, but both decreased with an increase in the gate angle. The velocity on the left side was almost constant, but the discharge increased due to a larger flow cross-section. More flow was diverted to the left side with an increase in the gate opening angle. The discharge on the right side was increased while the discharge on the left was decreased by increasing the length of the gradual transition. Increasing the gate angle or reducing the transition length resulted in a greater share of flow passing through the left side overall. Energy loss increases directly with flow rate and has an inverse relationship with the gate opening angle. The highest energy loss occurred at a 35-degree opening and the lowest at 85 degrees. Finally, relationships are presented that determine the discharge through both sides of the rotary gate and the energy loss in this structure. https://civil-ferdowsi.um.ac.ir/article_47986.html Extreme Increases or decreases in the temperature of asphalt mixtures causes damages such as rutting and thermal cracking in asphalt pavements. The purpose of this study is to evaluate the impact of incorporating phase-change material (PCM) as an additive in asphalt binder to control the temperature of asphalt mixture. For this purpose, polyaniline (PANI) was utilized as the shell material, while coconut (Co) oil was employed as the core phase-change material. This PCM was blended with asphalt binder at weight percentages of 3%, 7%, and 10%, A comprehensive testing program was conducted including Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Rotational Viscosity (RV), Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR), Pressure Aging Vessel (PAV), RTFO and Multiple Stress Creep Recovery (MSCR) tests. DSC results confirm an increase in the thermal energy storage capacity of the modified bitumen, demonstrating over 90% improvement in energy absorption. Analysis of the BBR data—specifically the creep stiffness (St) and m-value—indicates that the low-temperature performance grade of the pure bitumen is -12°C, while for the PCM-modified samples, it improves to -18°C. https://civil-ferdowsi.um.ac.ir/article_47998.html The conventional design of truss retaining structures in engineering practice is predominantly based on Rankine's lateral earth pressure theory, which neglects the actual soil-structure interaction. This research utilizes advanced three-dimensional numerical modeling in FLAC3D to compare the actual lateral pressure distribution with Rankine's theory and to evaluate its consequences on the design of the structural members. The results of parametric analyses indicate that the lateral pressure distribution is highly non-linear due to the arching phenomenon, concentrating at the truss connection points. The total lateral force in shallow excavations is considerably greater than the predictions of Rankine's theory, though this difference diminishes with increasing depth. More importantly, the resultant force's point of application is, on average, at a height of 0.42H from the base, which is significantly higher than the 0.33H assumed in Rankine's theory. These findings reveal that the traditional design approach leads to an uneconomical design for the vertical pile while simultaneously resulting in a potentially unconservative design for the critical raker member, thereby underscoring the necessity of revising current design practices. https://civil-ferdowsi.um.ac.ir/article_48027.html Given the environmental challenges posed by the extraction of natural aggregates and the increase in industrial waste, this research aims to investigate the technical and functional aspects of using waste foundry filler and silver nanoparticles in asphalt mastic for slurry seal pavement preservation. Compositions with different percentages of natural filler replacement with waste filler (0 to 100%) and with or without nanosilver (10% by weight relative to the total filler) were designed at three levels of residual asphalt. The evaluation of the compositions included physical, chemical, and X-ray fluorescence (XRF) tests, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and field emission scanning electron microscopy (FESEM), as well as performance tests such as wet abrasion, wet adhesion, and wheel tracking. The results showed that the waste filler, due to the presence of siliceous compounds and iron-containing phases, has good surface reactivity, and the addition of nanosilver improved particle distribution, structural integrity, and abrasion resistance. The composition containing 50% waste filler and nanosilver showed the best performance. The findings emphasize the usability of industrial waste for the production of high-performance and environmentally friendly cold-mix preservation asphalt. https://civil-ferdowsi.um.ac.ir/article_48182.html Fiber-reinforced polymers (FRP) are widely used for strengthening and rehabilitating reinforced concrete (RC) structures due to their high tensile strength, corrosion resistance, light weight, and durability, offering a more efficient alternative to conventional techniques that increase structural mass and member dimensions. Despite these advantages, fire represents a critical hazard for FRP-confined concrete, as elevated temperatures can deteriorate both the concrete matrix and the polymeric resin, thereby reducing the effectiveness of confinement. Although FRP systems are increasingly applied in structural retrofitting, limited research has addressed the residual mechanical performance of FRP-strengthened concrete after exposure to high temperatures. This study investigates the influence of elevated temperatures on cylindrical concrete specimens confined with glass fiber sheets. Twelve concrete cylinders (100 mm in diameter and 200 mm in height) were wrapped with two layers of glass fiber reinforcement, cured, and then exposed to temperatures of 100°C, 200°C, and 300°C for one hour before being gradually cooled to room temperature. The specimens were subsequently tested under uniaxial compression. The results demonstrate that glass fiber confinement enhances compressive strength, while increasing temperature levels reduce this strength gain compared with unheated control specimens. https://civil-ferdowsi.um.ac.ir/article_48369.html Road traffic accidents represent a major global public health challenge, resulting in substantial human and economic losses each year. However, these incidents exhibit discernible patterns and are, to some extent, predictable. Examining them from a spatial perspective can therefore contribute to a better understanding of the underlying factors and support risk reduction strategies. Recent studies have shown that traffic accidents often display significant spatial autocorrelation, necessitating the use of appropriate statistical methods to quantify and analyze such dependencies. Accordingly, the aim of this study is to investigate the spatial distribution of traffic accidents in the city of Zanjan using the Moran’s I spatial autocorrelation index within a GIS environment. To this end, a set of influential variables—including population density, density of major land uses, intersection density, road network density, commercial and service land uses, and trip attraction intensity—were examined to determine their relationship with accident occurrence patterns. The results indicate that all examined variables exhibit a significant and positive association with traffic accidents, with the strongest effects observed for population density, major land uses, intersection density, and trip attraction intensity. Furthermore, spatial analysis reveals that the distribution of accidents in Zanjan follows a clustered pattern, with distinct high-risk (hotspot) areas clearly identifiable. The findings of this study can serve as an effective tool for urban planners and decision-makers in developing targeted strategies to reduce traffic accidents. https://civil-ferdowsi.um.ac.ir/article_48370.html Despite the potential of seawater and dredged marine sand as sustainable alternatives in concrete production, the presence of ions such as Cl⁻, SO₄²⁻, Mg²⁺, and Ca²⁺ may promote microcrack propagation and reduce long-term durability. In this study, the interaction between microbial-induced calcium carbonate precipitation (MICP) mediated by Bacillus subtilis and silica fume (SF) in seawater sea-sand concrete (SWC) was investigated. The results indicate that the self-healing mechanism is governed by multi-ionic equilibrium, and the efficiency of the MICP pathway strongly depends on ionic ratios, particularly Ca²⁺. The reduction of the Ca/Si ratio in the presence of SF, due to the consumption of Ca(OH)₂ and formation of C–S–H phases, limited the availability of Ca²⁺ for MICP activity and reduced precipitation uniformity. In contrast, maintaining an effective Ca²⁺ concentration facilitated continuous nucleation and growth of CaCO₃ crystals along crack surfaces. Moreover, Mg²⁺ altered the precipitation pathway toward less stable polymorphs such as aragonite, while SO₄²⁻ ions reduced the healing capacity by promoting ettringite formation. Overall, although SF improves pore structure and reduces permeability, its synergistic efficiency with MICP is highly dependent on precise control of pore solution chemistry, particularly Ca²⁺ balance. https://civil-ferdowsi.um.ac.ir/article_48481.html Groundwater is recognized as the primary source of water supply in arid and semi-arid regions. The Central Plateau of Iran is one of the most critical regions of the country in terms of water resources, experiencing a severe decline in groundwater levels due to low precipitation, high evapotranspiration, and excessive groundwater abstraction. Under such conditions, quantitative estimation of groundwater recharge and understanding its spatiotemporal variability are essential components of sustainable water resources management.Despite its importance, regional-scale groundwater recharge estimation is associated with considerable uncertainty due to the limited availability of in situ data and the uneven spatial distribution of meteorological and piezometric stations. Recent advances in remote sensing data, particularly GRACE satellite observations and atmospheric reanalysis products such as ERA5-Land, have enabled the monitoring of terrestrial water storage changes and water balance components at large spatial scales. The objective of this study is to quantitatively estimate and analyze the spatiotemporal patterns of annual groundwater recharge in the Central Plateau of Iran by integrating GRACE, ERA5-Land, and ground-based observations, and to evaluate the applicability of these datasets for long-term groundwater monitoring in arid regions. https://civil-ferdowsi.um.ac.ir/article_48586.html In recent years, due to the high costs of pavement construction and environmental concerns, various waste materials have been incorporated into concrete pavements. In this study, the mechanical properties, impact resistance, and abrasion resistance of roller-compacted concrete containing reclaimed asphalt pavement and blast furnace slag have been investigated. The results indicate that recycled materials have diverse effects on the mechanical properties of roller-compacted concrete pavements. Specifically, the maximum compressive and flexural strengths at the optimal slag cement content (30 percent) increased by 24% and 6%, respectively, compared to the control specimen. Furthermore, increasing the slag content improved the abrasion resistance of the roller-compacted concrete by at least 13% across all replacement levels (replacing cement, fine aggregate, and coarse aggregate). Overall, the findings demonstrate that specimens containing slag cement, as well as a combination of fine slag and fine reclaimed asphalt pavement, exhibit excellent impact resistance. Therefore, it is recommended to utilize reclaimed asphalt pavement and slag waste materials in roller-compacted concrete pavements through appropriate mix designs, considering their satisfactory mechanical performance, positive environmental impact, and economic feasibility. https://civil-ferdowsi.um.ac.ir/article_48662.html Abstract Accurate prediction of surface settlement induced by urban tunneling is essential for mitigating geotechnical risks and protecting adjacent structures. This study investigates the prediction of maximum surface settlement caused by Earth Pressure Balance (EPB) tunneling in Mashhad Urban Railway Lines 2 and 3 using machine learning techniques. A database consisting of 292 samples was compiled from geotechnical investigations, geometric characteristics, and Tunnel Boring Machine (TBM) operational parameters, and 20 key input variables were selected. Three predictive models, including Artificial Neural Network (ANN), Deep Neural Network (DNN), and Random Forest (RF), were developed and compared. The results indicated that the DNN model with three hidden layers achieved the best performance, yielding a coefficient of determination (R²) of 0.9896 and the lowest mean squared error. Sensitivity analysis based on the Garson and Olden methods was further conducted to identify the most influential parameters affecting settlement behavior. The novelty of this research lies in the development of a data-driven model based on real-world tunneling data from the Mashhad Metro, the integrated use of geotechnical and TBM operational parameters, and the quantitative comparison of machine learning predictions with the conventional Peck empirical method. The proposed DNN model demonstrated substantially higher accuracy than the Peck method and can serve as a reliable tool for settlement risk assessment and management in urban tunneling projects. https://civil-ferdowsi.um.ac.ir/article_48711.html Use of helical piles is expanding due to their unique characteristics and special application in engineering projects for foundation improvement. In this research, the bearing capacity and settlement behavior of helical piles in sandy soil under compressive loading were studied through three-dimensional numerical modeling using the finite element method implemented in PLAXIS software. Various parameters of blade plate diameter, pile length, blade plate spacing, and pile spacing in the pile group were investigated. The results of the studies showed that the bearing capacity of helical piles increases significantly compared to conventional piles without blade plates, so that increasing the pile length leads to improved bearing capacity. Increasing the distance between the blade plates improves bearing capacity as long as the pile continues to behave as a unified system and remains within the cylindrical shear failure mechanism; the transfer boundary of the cylindrical shear behavior was obtained at a distance of about three times the blade plate diameter. The minimum distance between the piles in the group to reduce the overlap of the stressed areas was observed to be three times the diameter of the spiral blade. The values and trends of the results obtained from the numerical analysis showed a good agreement with the values of the theoretical analysis. https://civil-ferdowsi.um.ac.ir/article_48767.html As the construction of tall buildings increasingly expands in regions close to seismic faults, accurately assessing the effects of near-field ground motions on their seismic vulnerability has become important. Although numerous studies have investigated the seismic fragility of tall buildings, comparative assessment of tall reinforced concrete frame-core buildings under near-field and far-field earthquakes remains limited, particularly across different damage states. This study aims to probabilistically evaluate and compare the seismic vulnerability of a 35-story reinforced concrete building with a moment-resisting frame and coupled shear walls subjected to near-field and far-field earthquake records. A three-dimensional nonlinear model was developed in Perform-3D, and Incremental Dynamic Analysis (IDA) was conducted using two sets of ground-motion records. The maximum inter-story drift ratio was adopted as the primary engineering demand parameter, and fragility curves were developed for four damage states: slight, moderate, extensive, and complete. The results revealed substantial differences in the seismic response and fragility of the building under the two record sets. The median fragility values for far-field earthquakes were 0.045g, 0.185g, 0.7g, and 2.1g for the four damage states, respectively, whereas the corresponding values for near-field earthquakes were 0.03g, 0.12g, 0.55g, and 1.1g. At the complete damage state, the median fragility under near-field earthquakes decreased by approximately 55%, indicating a substantially higher probability of failure. The findings highlight the importance of considering near-field effects in the probabilistic seismic performance assessment of tall reinforced concrete frame-core buildings. https://civil-ferdowsi.um.ac.ir/article_48769.html A significant portion of Iran’s railway network is located on old bridges, particularly masonry bridges. Given the age and historical importance of these bridges, their preservation and maintenance are essential. In this study, numerical modeling of the Karaj masonry bridge and the passing train was conducted to investigate the effects of different track systems, including ballasted, concrete slab, and ladder tracks, on train–bridge interaction under different train speeds and axle loads. Based on the available material strength tests as well as static and dynamic field tests conducted on the bridge during the passage of different trains at various operating speeds, a detailed numerical model of the bridge–train system was first developed and validated. After confirming the reliability of the model, sensitivity analyses were performed for each track system to investigate the effects of axle load and train speed on the structural response. The results showed that increasing the axle load increased the vertical displacement and acceleration in all three track systems. The maximum vertical displacement at the center of the first span was 1.119, 0.86, and 0.81 mm for the ballasted, ladder, and concrete slab tracks, respectively. The corresponding maximum vertical accelerations at this location were 0.2687, 0.1864, and 0.1672 m/s², respectively. Overall, the concrete slab track produced the lowest vertical displacement and acceleration. The speed range corresponding to the maximum dynamic response varied between 90 and 120 km/h, depending on the track system and the response parameter considered. https://civil-ferdowsi.um.ac.ir/article_48856.html This study investigates the effect of chopped glass fibers on the mechanical properties of polymer concrete (PC) formulated with isophthalic and orthophthalic unsaturated polyester resins. The primary objective is to evaluate the compressive, tensile, and flexural strengths of PC using varying fiber percentages and lengths. To accurately predict mechanical behavior, cubic regression modeling coupled with the backward elimination method was employed, and the statistical significance of all model coefficients was rigorously evaluated. Experimental results indicated that adding glass fibers significantly improves tensile and flexural strengths by controlling crack propagation and optimizing stress distribution. Performance peaked at an optimal fiber dosage; however, excessive fiber length or content compromised mixture uniformity and hindered specimen fabrication. Statistically, the final cubic models demonstrated excellent agreement with experimental data. By eliminating non-significant terms (P-value > 0.05) and retaining only highly significant variables (P-value < 0.05), the models effectively captured the complex interaction effects between fiber length and content. Furthermore, a comparative analysis revealed that specimens formulated with isophthalic resin exhibited superior overall mechanical performance compared to those with orthophthalic resin.