@article { author = {Amezquita-Sancheza, J.P. and Valtierra-Rodriguez, M. and Adeli, H.}, title = {Machine learning in structural engineering}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2645-2656}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2020.22091}, abstract = {This article presents a review of selected articles about structural engineering applications of machine learning (ML) in the past few years. It is divided into the following areas: structural system identification, structural health monitoring, structural vibration control, structural design, and prediction applications. Deepneural networkalgorithms have beenthe subject of a large number of articles in civil and structural engineering.There are, however, otherML algorithms with great potential in civil and structural engineering that are worth exploring. Four novel supervised ML algorithms developed recently by the senior author and his associates with potential applications in civil/structural engineering are reviewed in this paper. They are the Enhanced Probabilistic Neural Network (EPNN), the Neural Dynamic Classification (NDC) algorithm, the Finite Element Machine (FEMa), and the Dynamic Ensemble Learning (DEL) algorithm}, keywords = {Civil structures,Machine learning,Deep Learning,Structural Engineering,System Identification,structural health monitoring,vibration control,Structural Design,Prediction}, url = {https://scientiairanica.sharif.edu/article_22091.html}, eprint = {https://scientiairanica.sharif.edu/article_22091_a1f7307103a395e03de4ea4e3f2b0a6f.pdf} } @article { author = {Jamshidi Chenari, R. and Kamyab Farahbakhsh, H. and Izadi, A.}, title = {Continuous slip surface method for stability analysis of heterogeneous vertical trenches}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2657-2668}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2019.21227}, abstract = {Evaluating the reliability of trenches against sliding failure is complicated by the fact that most alluvial deposits are heterogeneous and spatially variable. This means that instead of perfectly circular or linear failure surfaces, trench failure tends to be more complex, following the weakest path or zones through the material, thereby, a new method named Continuous Slip-Surface (CSS) is adopted for calculating the critical excavation depth. CSS runs an algorithm to seek for continuous slip surface. The Finite Difference Method (FDM) coupled with random field theory and CSS method is well suited to slope stability calculations since it allows the failure surface to seek out the weakest path through the soil. For an unsupported vertical cut, it was shown that the critical excavation depth acquired from CSSM is indeed an upper bound solution. It was further shown both numerically and analytically through an idealized variation model that increasing the un-drained shear strength density fades the effect of shear strength variability. Correlation structure of the input variable was also shown to influence the results, although the behaviour was found different in low and high scales of fluctuation.}, keywords = {Critical Excavation Depth,Random Field Theory,Continuous Slip Surface,Vertical Trench,Un-drained Shear Strength}, url = {https://scientiairanica.sharif.edu/article_21227.html}, eprint = {https://scientiairanica.sharif.edu/article_21227_fcb5b9b6bbd60f69251454e54961ca7f.pdf} } @article { author = {Wang, C. and Ye, Z. and Chen, E. and Feng, J.}, title = {Space headway calculation and analysis at turn movement trajectories using hybrid model}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2669-2679}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2019.21308}, abstract = {Space headway calculation and analysis play an important role in identifying surrounding obstacles and understanding traffic scene. However, the performance of existing methods is limited by the complexity of computer processing. In addition, it is quite difficult to obtain space headway at turn movement trajectories, mainly owing to the limitation of rectilinear propagation. Therefore, a hybrid model based on spline curve and numerical integration was proposed to estimate distance of the front vehicle and vehicle trajectory in this study. The space headway at turn movement trajectories was analogous to the track of a vehicle, which could be fitted by a quadratic spline curve. Newton-Cotes numerical integration was employed to calculate distance due to its meshing flexibility and ease of implementation. Data collected from Lankershim Boulevard in the city of Los Angeles, California (USA) were used to evaluate performance of the hybrid model. Compared with another algorithm based on computer vision and trilinear method, the results showed that the proposed model worked successfully and outperformed the competing method in terms of accuracy and reliability. Finally, the proposed method was applied to investigate the effects of vehicle speed, relative speed of vehicles, and time period on the spacing of vehicles during car-following.}, keywords = {space headway,spline curve,numerical integration,car-following,turn movement trajectories}, url = {https://scientiairanica.sharif.edu/article_21308.html}, eprint = {https://scientiairanica.sharif.edu/article_21308_ed71276f8fb3dfd5519a741ed5ab4a98.pdf} } @article { author = {Sharbatdar, M.K. and Ayyubi, J.}, title = {Flexural retrofitting of the damaged reinforced concrete beams by using HPFRCC}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2680-2689}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2020.21737}, abstract = {Damaged structures are not usually reliable to tolerate designed loads and therefor, need to retrofit in structural parts. The main purpose of this paper is to utilize HPFRCC as a high-performance material to recover the damaged beams and improve their ductility and moment capacity with experimental approaches. In addition to, a retrofitting method is presented using high-performance fibre reinforced cement-based composite (HPFRCC). The experimental study is performed on three simply supported beams with the same dimension, materials, and reinforcement configuration. The first beam, which is known as the reference beam (RC), is subjected to pure bending condition till its failure and the others are prone to a certain amount of load according to the final capacity of the first beam. Thereafter, two damaged beams are retrofitted using HPFRCC in the created grooves on tensile surface of the beam and finally these retrofitted beams are loaded to determine the bending behaviour. Experimental Results demonstrate that retrofitting can improve the first crack strength, load at yield condition, and maximum load capacity. Also, the proposed method increases the ductility and energy absorption of retrofitted beams.}, keywords = {HPFRCC,Damaged,Retrofitting,Steel fibres,ductility,Flexural capacity,numerical}, url = {https://scientiairanica.sharif.edu/article_21737.html}, eprint = {https://scientiairanica.sharif.edu/article_21737_28b945ca5b849cccd72d182e1bc1a9c1.pdf} } @article { author = {Samimi, A. and Rahimi, E. and Amini, H. and Jamshidi, H.}, title = {Freight modal policies toward a sustainable society}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2690-2703}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2019.21386}, abstract = {Freight transport policy analysts struggle to shift truck freight movements to rail to diminish transportation externalities including environmental costs and safety issues. Therefore, policy-makers need to be aware of the consequences of their decisions beforehand. This study is mainly focused on two policies targeting fuel price and access to rail transportation. A nation-wide freight mode choice model is developed for Iran, and shippers’ tendency to choose rail or truck freight transportation is analyzed by considering the shipping time and cost, commodity weight, commodity type, and rail accessibility. Total fuel consumption and air pollution costs are compared in various scenarios. Based on the results, environmental transportation costs are significantly reduced as a result of the modal shift from truck to rail freight transportation, if the government reallocates the gasoline subsidy to the construction of prioritized railroads.}, keywords = {Truck freight transportation,rail freight transportation,mode choice policy,energy subsidy,air pollution,transportation costs}, url = {https://scientiairanica.sharif.edu/article_21386.html}, eprint = {https://scientiairanica.sharif.edu/article_21386_c330f891cd8e72ca7ce1e9a3e8d02f3b.pdf} } @article { author = {Keshavarz, A. and Tofighi, H.}, title = {Gene expression programming models for liquefaction-induced lateral spreading}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2704-2718}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2018.50125.1525}, abstract = {Lateral spreading is one of the most significant destructive and catastrophic phenomena associated with liquefaction caused by earthquake and can impose very serious damages to structures and engineering facilities. The aim of this study is to evaluate liquefaction induced lateral spreading and finding new relations using gene expression programming (GEP) that is a new and developed generation of genetic algorithms approaches. Since there are complicated, nonlinear and higher order relationships between many factors affecting the lateral spreading, GEP is assumed to be capable of finding complex and accurate relationships between these factors. This study includes three main stages: (i) compilation of available database (484 data), (ii) dividing data into training and testing categories, and (iii) building new models and propose new relationships to predict ground displacement in free face, gentle slope and general ground conditions. The results of modeling each of the different ground conditions are presented in the form of mathematical equations. At the end, the final GEP models for 3 different cases of ground conditions are compared with multiple linear regression (MLR) and other published models. The statistical parameters indicate the higher accuracy of the GEP models over other relations.}, keywords = {Liquefaction,lateral spreading,gene expression programming,free face,gentle slope}, url = {https://scientiairanica.sharif.edu/article_21139.html}, eprint = {https://scientiairanica.sharif.edu/article_21139_588ef3b5092a369f0e2dfdd260258f4e.pdf} } @article { author = {Ibrahim, N.A. and Rashid, A.S.A. and Yunus, N.Z.M. and Latifi, N. and Horpibulsuk, S.}, title = {Sustainable use of stabilized flood mud as subgrade soil for low volume traffic roads}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2719-2726}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2019.50523.1749}, abstract = {This research was carried out to identify the basic properties of flood mud and the efficiency of biomass silica (SH85) as a stabiliser to improve the strength of this mud. Unconfined Compressive Strength (UCS) testing was carried out on untreated soil and soil treated with 2%, 4%, and 9% SH85 at three and seven curing days. The microstructure of SH85 treated flood mud was investigated via field-emission scanning electron microscopy (FESEM) and Energy-Dispersive X-Ray spectrometry (EDX) analyses. It was found that the strength of treated soil increases two to seven times that of the untreated soil strength where the highest strength was recorded at 949 kPa after the soil had been treated with 9% of SH85 for seven days. A polynomial trend was observed with an R2 greater than 95% relationship between SH85 content versus UCS, with different curing periods. The seven-day UCS of SH85 treated flood mud meets the strength requirement of 0.8 MPa for Malaysian subgrade material of low traffic volume roads and the compressibility was significantly reduced when SH85 content was greater than 4%. It was found from the FESEM and EDX results that cementitious products leading to strength improvement fill the voids of the treated soil.}, keywords = {flood mud,subgrade,unconfined compressive strength,microstructure,SH85 stabiliser}, url = {https://scientiairanica.sharif.edu/article_21240.html}, eprint = {https://scientiairanica.sharif.edu/article_21240_84fb13a7841d2357fb155b70741c0a0e.pdf} } @article { author = {Samadvand, H. and Dehestani, M.}, title = {Near free-edge stresses in FRP-to-concrete bonded joint due to mechanical and thermal loads}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2727-2739}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2018.50594.1779}, abstract = {Over the last few decades, a considerable amount of theoretical and experimental investigations have been conducted on the mechanical strength of composite bonded joints. Nevertheless, many issues regarding the debonding behavior of such joints still remain uncertain. The high near free-edge stress fields in most of these joints are the cause of their debonding failure. In this study, the performance of an externally bonded fiber-reinforced polymer (FRP) fibrous composite to a concrete substrate prism joint subjected to mechanical and thermomechanical loadings is evaluated through employing the principles of lamination theory. An inclusive Matlab code is generated to perform the computations. The bond strength is estimated to take place in a region- also termed the boundary layer- where the peak interfacial shearing and transverse peeling stresses occur; whereas the preceding stress field is observed to be the main failure mode of the joint. The proposed features are validated through the existing experimental data points as well as the commercial finite element (FE) modeling software Abaqus. Comparison between the calculated and experimental results demonstrates favorable accord, producing quite a high average ratio. The current approach is advantageous to failure modeling analysis, optimal design of bonded joints, and scaling analyses among others.}, keywords = {FRP-to-concrete bonded joint,thermomechanical load,free-edge interfacial stress,boundary layer,debonding failure,Finite Element Method}, url = {https://scientiairanica.sharif.edu/article_21199.html}, eprint = {https://scientiairanica.sharif.edu/article_21199_ffc5b7905f572246c583126ae1a442ca.pdf} } @article { author = {Zacchei, E. and Molina, J.L.}, title = {Application of artificial accelerograms to estimating damage to dams using failure criteria}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2740-2751}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2018.50699.1824}, abstract = {The aim of this paper is to analyse dam’s damage by using two recent methodologies. The first method has been used to define the performance and response curves of concrete gravity dams. The second method defines the seismic input which has been obtained from power spectral density function consistent with the response spectrum. Both methods set themselves as efficient, practical and useful to develop quite complicated analysis as the construction of the stochastic process to define the synthetic earthquake and the estimation of cracks in the dam’s body. These methodologies have been explained and revised to improve their use. The fluid behaviour contained by arch-dams is compared with the fluid behaviour in storage tanks by studying the sloshing phenomenon which is usually neglected for dams. For the mathematical modelling, interactive programming language has been used.}, keywords = {Earthquake damage estimation,failure modes,power spectral density function,concrete arch-dams,storage tanks,sloshing mode}, url = {https://scientiairanica.sharif.edu/article_21148.html}, eprint = {https://scientiairanica.sharif.edu/article_21148_d4d2d340ec05ad4f0728e4f234e8cf1d.pdf} } @article { author = {Fanaie, Nader and Partovi, Fatemeh}, title = {Control of natural frequency of beams using different pre-tensioning cable patterns}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2752-2774}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2019.50725.1835}, abstract = {Steel cable is utilized in this research to control the natural frequency of beam due to its important advantages such as low weight, small cross-sectional area and high tensile strength. In this study, for the first time, theoretical relations are developed to calculate the increase in pre-tensioning force of steel cables under external loading based on the method of least work. Moreover, the natural frequency of steel beams with different support conditions without cable and with different patterns of cable is calculated based on Rayleigh’s method. To verify the theoretical relations, the steel beam is modeled in the finite element ABAQUS software with different support conditions without cable and with different cable patterns. The obtained results show that the theoretical relations can appropriately predict the natural frequency of beams with different support conditions and different cable patterns. In this study, simply supported as well as fixed supported beams are pre-stressed with v-shaped and modified v-shaped patterns of the cable. According to the obtained results, the modified v-shaped pattern of the cable is more efficient than the v-shaped pattern one. Furthermore, the effects of the length of horizontal cables on the natural frequency are studied.}, keywords = {natural frequency,steel beam,cable,pre-tensioning,least work,Rayleigh’s method}, url = {https://scientiairanica.sharif.edu/article_21326.html}, eprint = {https://scientiairanica.sharif.edu/article_21326_1fc5a3dc4216aa0351731dc74aa14120.pdf} } @article { author = {Pouria Mirzaei, P. and Gerami, M.}, title = {Collapse assessment of protected steel moment frame under post-earthquake fire}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2775-2789}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2019.51391.2148}, abstract = {This paper investigates the behavior of low-, medium- and high-rise protected steel moment resisting frames under post-earthquake fire through two different methods. In the first method, the pushover analysis is utilized to simulate the response of the sample structures for various target displacements. Then the thermo-mechanical analysis is implemented to evaluate the behavior of the damaged frames under fire, assuming that the fireproofing is delaminated at the end regions of the beams. In the second method, the seismic response of the frames under two sets of the MCE-scaled near and far fault ground motion records is determined employing the time history analysis. In this method, the damage of fireproofing is characterized by the maximum inter-story drift ratio. The results of the study revealed that the method 1 give similar results to the method 2, for most cases. It is also found that for sufficiently large drift demands, the collapse of the frames under post-earthquake fire occurs in side-way mode, while for lower seismic responses, the local failure of beams dominates other failure modes. Moreover, it was found that the reduction of fire resistance time due to the effects of MCE seismic loads ranges 4% to 26% for the considered structures.}, keywords = {Fire after earthquake,Fireproofing,Heat Transfer,Side-way collapse,Thermal-mechanical analysis}, url = {https://scientiairanica.sharif.edu/article_21242.html}, eprint = {https://scientiairanica.sharif.edu/article_21242_e37214fa90829c68e40a691740eacfa7.pdf} } @article { author = {Shakarami, B. and Kabir, M.Z. and Sistani Nejad, R.}, title = {Numerical modeling of a new reinforced masonry system subjected to in-plane cyclic loading}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2790-2807}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2019.5376.1237}, abstract = {This paper describes the behavior of walls under in-plane cyclic shear compression loads of a new reinforced masonry system composed of horizontally and vertically reinforcement based on Iran's national building regulation in two groups. First, steel bars in grid-type are mounted in the cement core between solid clay bricks (Double-Wythe) and in the second group, common steel bars in grid-type are mounted in perforated bricks and trusses as horizontal reinforcement, using advanced numerical simulation (LS-DYNA). A nonlinear finite element discrete modeling according to stress-strain models have been used in order to represent previously modeled masonry walls. Masonry units include perforated bricks and solid clay bricks, the mortar and bonding interfaces have been shown as continuum elements. In order to validate micro-modeling strategy, the input data, based on a reinforced masonry wall was previously tested in the laboratory with a clear identification and justification. That being so, the major purpose of this paper is: (a) the results of specimens in terms of maximum strength, ductility, energy absorption and failure modes (b) influence of aspect ratio and reinforcement type and (c) the comparison of modeled walls with other reinforced systems.}, keywords = {Reinforced Masonry (RM),Un-Reinforced Masonry (URM),ductility,energy absorption,in-plane cyclic loading}, url = {https://scientiairanica.sharif.edu/article_21243.html}, eprint = {https://scientiairanica.sharif.edu/article_21243_387e09c8d144d1c454581b75a171d766.pdf} } @article { author = {Shams, B. and Ardakani, A. and Roustaei, M.}, title = {Laboratory investigation of geotextile position on CBR of clayey sand soil under freeze-thaw cycle}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2808-2816}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2019.5461.1284}, abstract = {In cold regions, soil experiences repetitive freeze–thaw cycles that are considered as one of the most important phenomena in cold region engineering. Approximately 30 percent of soils around the world and a large portion of fertile lands are subjected to daily or seasonal freeze-thaw cycles. These cycles cause considerable changes in water content, solute movement, permeability, strength parameters, erosion rate, and other physical or chemical characteristics of the soil. Nowadays, one of the ways for improvement the physical and mechanical characteristics of the soil is to incorporate geosynthetic material as a layer between the embankment and the ground surface. This paper presents results of some California Bearing Ratio tests a clayey sandy soil. Moreover, effect of freeze–thaw cycles on the compressive strength of geotextile-reinforced soil is investigated. The geotextile layer was placed in five positions in different depths of 1.3, 2.6, 3.9, 5.85 and 7.8 cm beneath the surface of the mold and then the sample was exposed to freeze-thaw cycles. It was found that the optimum depth of the geotextile layer is 3.9 cm. In addition, it could be observed that reinforcing the soil can diminish the weakening effect of freeze-thaw cycles up to 41.7%.}, keywords = {geotextile,California bearing ratio,freeze-thaw cycling,clayey sand soil,Soil stabilization}, url = {https://scientiairanica.sharif.edu/article_21244.html}, eprint = {https://scientiairanica.sharif.edu/article_21244_00dbb998bcc7dbefc4cc47e0196dfc96.pdf} } @article { author = {Alvanchi, A. and Seyrfar, A.}, title = {Improving facility management of public hospitals in Iran using building information modeling}, journal = {Scientia Iranica}, volume = {27}, number = {6}, pages = {2817-2829}, year = {2020}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2019.50186.1562}, abstract = {Improving management of complex and congested facilities in hospital buildings is a potential point for both reducing money spent and enhancing quality level of the medical services provided in public hospitals of Iran. Although building information modeling (BIM) is identified as an effective tool for improving facility management (FM), use of advantages it offers to the FM processes of hospitals has been neglected thus far in the country. To address this issue, this research aims to investigate the BIM capabilities and the supporting organizational structure public hospitals in Iran can adopt to improve their FM processes. A comprehensive literature review was conducted on applicable capabilities of BIM to the FM processes. Hierarchical FM structure of public hospitals in the country was recognized through review of the related regulations. A public hospital case was chosen for an in-depth recognition of FM processes operations and validation of the proposed BIM-based improvements. It was argued the use of BIM capabilities can cause substantial improvements in the FM processes of the public hospitals. Reduced duration of FM activities, improved facility layouts, enhanced communication and coordination, facilitated training, and improved emergency management are some expected outcomes.}, keywords = {Building information modeling,Facility management,Public hospitals,Hospital building}, url = {https://scientiairanica.sharif.edu/article_21231.html}, eprint = {https://scientiairanica.sharif.edu/article_21231_84cf3a3173a03b9f8da73bde92fb3285.pdf} }