Pub Date : 2020-07-23DOI: 10.31814/10.31814/stce.nuce2020-14(3)-06
Nguyen Cong Giang, N. Manh, Nguyễn Quang Phích
In the field of rock mechanics, underground construction and mining, there have been many proposed methods for studying geo-hazards and also many research results that have been published in the world. In Vietnam, the numerical method is mainly used for analysis and design but not going deeply to predict the possible causes that lead to geo-hazards due to complex geological conditions. On the other hand, underground constructions and exploitation projects are often designed based on standards, regulations and experiences. The physical mechanism as well as the possibility of geo-hazards occurred when constructing underground structures and mining can take on various forms, depending on geological conditions and construction technology. Therefore, using numerical methods to simulate and analyze the possible geo-hazards is essential. This article presents a number of specific analysis cases, taking into account geological conditions and boundary conditions, and from that, raising a number of issues to note when using numerical methods. Keywords: underground mining; numerical method; geo-hazards; rock mechanics; FLAC2D.
{"title":"Numerical investigation on the tunneling and mining induced geo-hazards: Case study in Quang Ninh, Vietnam","authors":"Nguyen Cong Giang, N. Manh, Nguyễn Quang Phích","doi":"10.31814/10.31814/stce.nuce2020-14(3)-06","DOIUrl":"https://doi.org/10.31814/10.31814/stce.nuce2020-14(3)-06","url":null,"abstract":"In the field of rock mechanics, underground construction and mining, there have been many proposed methods for studying geo-hazards and also many research results that have been published in the world. In Vietnam, the numerical method is mainly used for analysis and design but not going deeply to predict the possible causes that lead to geo-hazards due to complex geological conditions. On the other hand, underground constructions and exploitation projects are often designed based on standards, regulations and experiences. The physical mechanism as well as the possibility of geo-hazards occurred when constructing underground structures and mining can take on various forms, depending on geological conditions and construction technology. Therefore, using numerical methods to simulate and analyze the possible geo-hazards is essential. This article presents a number of specific analysis cases, taking into account geological conditions and boundary conditions, and from that, raising a number of issues to note when using numerical methods. \u0000Keywords: \u0000underground mining; numerical method; geo-hazards; rock mechanics; FLAC2D.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82334815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-22DOI: 10.31814/stce.nuce2020-14(1)-04
H. Tai, N. Hieu, Vul Thang
In this paper the smoothed four-node element with in-plane rotations MISQ24 is combined with a C0-type higher-order shear deformation theory (C0-HSDT) to propose an improved linear quadrilateral plate element for static and free vibration analyses of laminated composite plates. This improvement results in two additional degrees of freedom at each node and require no shear correction factors while ensuring the high precision of numerical solutions. Composite plates with different lay-ups, boundary conditions and various geometries such as rectangular, skew and triangular plates are analyzed using the proposed element. The obtained numerical results are compared with those from previous studies in the literature to demonstrate the effectiveness, the reliability and the accuracy of the present element. Keywords: composite laminated plates; bending problems; free vibration; C0-HSDT; MISQ24.
{"title":"Bending and free vibration behaviors of composite plates using the C0-HSDT based four-node element with in-plane rotations","authors":"H. Tai, N. Hieu, Vul Thang","doi":"10.31814/stce.nuce2020-14(1)-04","DOIUrl":"https://doi.org/10.31814/stce.nuce2020-14(1)-04","url":null,"abstract":"In this paper the smoothed four-node element with in-plane rotations MISQ24 is combined with a C0-type higher-order shear deformation theory (C0-HSDT) to propose an improved linear quadrilateral plate element for static and free vibration analyses of laminated composite plates. This improvement results in two additional degrees of freedom at each node and require no shear correction factors while ensuring the high precision of numerical solutions. Composite plates with different lay-ups, boundary conditions and various geometries such as rectangular, skew and triangular plates are analyzed using the proposed element. The obtained numerical results are compared with those from previous studies in the literature to demonstrate the effectiveness, the reliability and the accuracy of the present element. \u0000Keywords: \u0000composite laminated plates; bending problems; free vibration; C0-HSDT; MISQ24.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88942192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-04DOI: 10.31814/stce.nuce2020-14(1)-08
Truong Viet Hung, Vũ Quang Việt, Vu Quoc Anh
The most rigorous effective medium approximations for elastic moduli are elaborated for matrix composites made from an isotropic continuous matrix and isotropic inclusions associated with simple shapes such as circles or spheres. In this paper, we focus specially on the effective elastic moduli of the heterogeneous composites with arbitrary inclusion shapes. The main idea of this paper is to replace those inhomogeneities by simple equivalent circular (spherical) isotropic inclusions with modified elastic moduli. Available simple approximations for the equivalent circular (spherical) inclusion media then can be used to estimate the effective properties of the original medium. The data driven technique is employed to estimate the properties of equivalent inclusions and the Extended Finite Element Method is introduced to modeling complex inclusion shapes. Robustness of the proposed approach is demonstrated through numerical examples with arbitrary inclusion shapes. Keywords: data driven approach; equivalent inclusion, effective elastic moduli; heterogeneous media; artificial neural network.
{"title":"A three-dimensional model for rain-wind induced vibration of stay cables in cable-stayed bridges","authors":"Truong Viet Hung, Vũ Quang Việt, Vu Quoc Anh","doi":"10.31814/stce.nuce2020-14(1)-08","DOIUrl":"https://doi.org/10.31814/stce.nuce2020-14(1)-08","url":null,"abstract":"The most rigorous effective medium approximations for elastic moduli are elaborated for matrix composites made from an isotropic continuous matrix and isotropic inclusions associated with simple shapes such as circles or spheres. In this paper, we focus specially on the effective elastic moduli of the heterogeneous composites with arbitrary inclusion shapes. The main idea of this paper is to replace those inhomogeneities by simple equivalent circular (spherical) isotropic inclusions with modified elastic moduli. Available simple approximations for the equivalent circular (spherical) inclusion media then can be used to estimate the effective properties of the original medium. The data driven technique is employed to estimate the properties of equivalent inclusions and the Extended Finite Element Method is introduced to modeling complex inclusion shapes. Robustness of the proposed approach is demonstrated through numerical examples with arbitrary inclusion shapes. \u0000Keywords: \u0000data driven approach; equivalent inclusion, effective elastic moduli; heterogeneous media; artificial neural network.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79871524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-31DOI: 10.31814/stce.nuce2019-13(3)-11
Truong Viet Hung, Vũ Quang Việt, Dinh Van Thuat
In the present study, Deep Learning (DL) algorithm or Deep Neural Networks (DNN), one of the most powerful techniques in Machine Learning (ML), is employed for estimation of ultimate load factor of nonlinear inelastic steel truss. Datasets consisting of training and test data are created based on advanced analysis. In datasets, input data are the member cross-sections of the truss members and output data is the ultimate load factor of the whole structure. An example of a planar 39-bar steel truss is studied to demonstrate the efficiency and accuracy of the DL method. Five optimizers such as Adadelta, Adam, Nadam, RMSprop and SGD and five activation functions such as ELU, LeakyReLU, Sigmoid, Softplus, and Tanh are considered. Based on analysis results, it is proven that DL algorithm shows very high accuracy in the regression of the ultimate load factor of the planar 39-bar nonlinear inelastic steel truss. The number of layers can be selected with a small value such as 1, 2 or 3 layers and the number of neurons in each layer can be chosen in the range [Ni, 3Ni] with Ni is the number of input variables of the model. The activation functions ELU and LeakyReLU have better convergence speed of the training process compared to Sigmoid, Softplus and Tanh. The optimizer Adam works well with all activation functions considered and produces better MSE values regarding both training and test data. Keywords: deep learning; artificial neural networks; nonlinear inelastic analysis; steel truss; machine learning.
{"title":"A deep learning-based procedure for estimation of ultimate load carrying of steel trusses using advanced analysis","authors":"Truong Viet Hung, Vũ Quang Việt, Dinh Van Thuat","doi":"10.31814/stce.nuce2019-13(3)-11","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-11","url":null,"abstract":"In the present study, Deep Learning (DL) algorithm or Deep Neural Networks (DNN), one of the most powerful techniques in Machine Learning (ML), is employed for estimation of ultimate load factor of nonlinear inelastic steel truss. Datasets consisting of training and test data are created based on advanced analysis. In datasets, input data are the member cross-sections of the truss members and output data is the ultimate load factor of the whole structure. An example of a planar 39-bar steel truss is studied to demonstrate the efficiency and accuracy of the DL method. Five optimizers such as Adadelta, Adam, Nadam, RMSprop and SGD and five activation functions such as ELU, LeakyReLU, Sigmoid, Softplus, and Tanh are considered. Based on analysis results, it is proven that DL algorithm shows very high accuracy in the regression of the ultimate load factor of the planar 39-bar nonlinear inelastic steel truss. The number of layers can be selected with a small value such as 1, 2 or 3 layers and the number of neurons in each layer can be chosen in the range [Ni, 3Ni] with Ni is the number of input variables of the model. The activation functions ELU and LeakyReLU have better convergence speed of the training process compared to Sigmoid, Softplus and Tanh. The optimizer Adam works well with all activation functions considered and produces better MSE values regarding both training and test data. \u0000Keywords: \u0000deep learning; artificial neural networks; nonlinear inelastic analysis; steel truss; machine learning.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73539382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-31DOI: 10.31814/stce.nuce2019-13(3)-08
N. Hải, Doan Ngoc Tinh Nghiem, L. Binh, L. Tin, Ngo-Huu Cuong
This paper presents the elastic large-displacement analysis of planar steel frames with flexible connections under static loads. A corotational beam-column element is established to derive the element stiffness matrix considering the effects of axial force on bending moment (P-Δ effect), the additional axial strain caused by end rotations and the nonlinear moment – rotation relationship of beam-to-column connections. A structural nonlinear analysis program is developed by MATLAB programming language based on the modified spherical arc-length algorithm in combination with the sign of displacement internal product to automate the analysis process. The obtained numerical results are compared with those from previous studies to prove the effectiveness and reliability of the proposed element and program.
{"title":"Large displacement elastic analysis of planar steel frames with flexible beam-to-column connections under static loads by corotational beam-column element","authors":"N. Hải, Doan Ngoc Tinh Nghiem, L. Binh, L. Tin, Ngo-Huu Cuong","doi":"10.31814/stce.nuce2019-13(3)-08","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-08","url":null,"abstract":"This paper presents the elastic large-displacement analysis of planar steel frames with flexible connections under static loads. A corotational beam-column element is established to derive the element stiffness matrix considering the effects of axial force on bending moment (P-Δ effect), the additional axial strain caused by end rotations and the nonlinear moment – rotation relationship of beam-to-column connections. A structural nonlinear analysis program is developed by MATLAB programming language based on the modified spherical arc-length algorithm in combination with the sign of displacement internal product to automate the analysis process. The obtained numerical results are compared with those from previous studies to prove the effectiveness and reliability of the proposed element and program.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86627025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-31DOI: 10.31814/stce.nuce2019-13(3)-01
Van-Dong Do, T. Le, A. Béakou
Ambient vibration testing is a preferred technique for heath monitoring of civil engineering structures because of several advantages such as simple equipment, low cost, continuous use and real boundary conditions. However, the excitation not controlled and not measured, is always assumed as Gaussian white noise in the processing of ambient responses called operational modal analysis. In presence of harmonics due to rotating parts of machines or equipment inside the structures, e.g., fans or air-conditioners…, the white noise assumption is not verified and the response analysis becomes difficult and it can even lead to biased results. Recently, transmissibility function has been proposed for the operational modal analysis. Known as independent of excitation nature in the neighborhood of a system's pole, the transmissibility function is thus applicable in presence of harmonics. This study proposes therefore to apply the transmissibility functions for modal identification of ambient vibration testing and investigates its performance in presence of harmonics. Numerical examples and an experimental test are used for illustration and validation. Keywords: operational modal analysis; transmissibility function; harmonic component; ambient vibration testing.
{"title":"Operational modal analysis of mechanical systems using transmissibility functions in the presence of harmonics","authors":"Van-Dong Do, T. Le, A. Béakou","doi":"10.31814/stce.nuce2019-13(3)-01","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-01","url":null,"abstract":"Ambient vibration testing is a preferred technique for heath monitoring of civil engineering structures because of several advantages such as simple equipment, low cost, continuous use and real boundary conditions. However, the excitation not controlled and not measured, is always assumed as Gaussian white noise in the processing of ambient responses called operational modal analysis. In presence of harmonics due to rotating parts of machines or equipment inside the structures, e.g., fans or air-conditioners…, the white noise assumption is not verified and the response analysis becomes difficult and it can even lead to biased results. Recently, transmissibility function has been proposed for the operational modal analysis. Known as independent of excitation nature in the neighborhood of a system's pole, the transmissibility function is thus applicable in presence of harmonics. This study proposes therefore to apply the transmissibility functions for modal identification of ambient vibration testing and investigates its performance in presence of harmonics. Numerical examples and an experimental test are used for illustration and validation. \u0000Keywords: \u0000operational modal analysis; transmissibility function; harmonic component; ambient vibration testing.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86747407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-31DOI: 10.31814/stce.nuce2019-13(3)-09
Phan Hai Dang, Le Duc Tho, L. Q. Hung, Dao Duy Kien
The current article is concerned with the interaction of Rayleigh waves with surface defects of arbitrary shape in a homogeneous, isotropic, linearly elastic half-space. Using a linear superposition principle, the interaction generates a scattered field which is equivalent to the field radiated from a distribution of horizontal and vertical tractions on the surface of the defect. These tractions are equal in magnitude but opposite in sign to the corresponding tractions obtained from the incident wave. The scattered field is then computed as the superposition of the displacements radiated from the tractions at every point of the defect surface using the reciprocity theorem approach. The far-field vertical displacements are compared with calculations obtained by the boundary element method (BEM) for circular, rectangular, triangular and arbitrary-shaped defects. Comparisons between the theoretical and BEM results, which are graphically displayed, are in excellent agreement. It is also discussed the limitations of the proposed approximate theory. Keywords: half-space; Rayleigh wave; surface defect; reciprocity theorem; boundary element method (BEM).
{"title":"Investigation of Rayleigh wave interaction with surface defects","authors":"Phan Hai Dang, Le Duc Tho, L. Q. Hung, Dao Duy Kien","doi":"10.31814/stce.nuce2019-13(3)-09","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-09","url":null,"abstract":"The current article is concerned with the interaction of Rayleigh waves with surface defects of arbitrary shape in a homogeneous, isotropic, linearly elastic half-space. Using a linear superposition principle, the interaction generates a scattered field which is equivalent to the field radiated from a distribution of horizontal and vertical tractions on the surface of the defect. These tractions are equal in magnitude but opposite in sign to the corresponding tractions obtained from the incident wave. The scattered field is then computed as the superposition of the displacements radiated from the tractions at every point of the defect surface using the reciprocity theorem approach. The far-field vertical displacements are compared with calculations obtained by the boundary element method (BEM) for circular, rectangular, triangular and arbitrary-shaped defects. Comparisons between the theoretical and BEM results, which are graphically displayed, are in excellent agreement. It is also discussed the limitations of the proposed approximate theory. \u0000Keywords: \u0000half-space; Rayleigh wave; surface defect; reciprocity theorem; boundary element method (BEM).","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74995477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-31DOI: 10.31814/stce.nuce2019-13(3)-04
N. N. Dương, N. Kien, N. T. Nhan
Buckling analysis of thin-walled composite channel beams is presented in this paper. The displacement field is based on classical beam theory. Both plane stress and plane strain state are used to achieve constitutive equations. The governing equations are derived from Lagrange’s equations. Ritz method is applied to obtain the critical buckling loads of thin-walled beams. Numerical results are compared to those in available literature and investigate the effects of fiber angle, length-to-height’s ratio, boundary condition on the critical buckling loads of thin-walled channel beams. Keywords: Ritz method; thin-walled composite beams; buckling.
{"title":"Ritz solution for buckling analysis of thin-walled composite channel beams based on a classical beam theory","authors":"N. N. Dương, N. Kien, N. T. Nhan","doi":"10.31814/stce.nuce2019-13(3)-04","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-04","url":null,"abstract":"Buckling analysis of thin-walled composite channel beams is presented in this paper. The displacement field is based on classical beam theory. Both plane stress and plane strain state are used to achieve constitutive equations. The governing equations are derived from Lagrange’s equations. Ritz method is applied to obtain the critical buckling loads of thin-walled beams. Numerical results are compared to those in available literature and investigate the effects of fiber angle, length-to-height’s ratio, boundary condition on the critical buckling loads of thin-walled channel beams. \u0000Keywords: \u0000Ritz method; thin-walled composite beams; buckling.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79459126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-31DOI: 10.31814/stce.nuce2019-13(3)-13
Le Thiet Trung, Duong Diep Thuy, Phạm Việt Anh
Results of in-situ tests showed that the performance of single isolated piles and individual piles within a group is largely different. When piles are arranged in a group, the interaction between piles and the foundation depends on the pile arrangement and the pile group effect. To date, studies on the pile group effect in Vietnam have been limited to reduced-scale laboratory testing or static load testing where piles are installed into homogeneous sandy or clayey foundation. This paper presents in situ tests which were performed on both single piles and pile groups, loaded to failure, with the aim of studying the pile group effect of piles embedded in multi-layered foundation. Strain gauges were installed along the shaft of 10 m long steel pipe piles, with a diameter of 143 mm. The influence of loose sand layers on the group effect in case of friction piles was evaluated. The experimental results indicated that the influence of sand layers was evident, and the group factor was calculated to be 1.237. Keywords: group efficiency; pile groups; axial capacity; load transfer.
{"title":"Experimental testing of a full-scale of group efficiency in multiple soil layers","authors":"Le Thiet Trung, Duong Diep Thuy, Phạm Việt Anh","doi":"10.31814/stce.nuce2019-13(3)-13","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-13","url":null,"abstract":"Results of in-situ tests showed that the performance of single isolated piles and individual piles within a group is largely different. When piles are arranged in a group, the interaction between piles and the foundation depends on the pile arrangement and the pile group effect. To date, studies on the pile group effect in Vietnam have been limited to reduced-scale laboratory testing or static load testing where piles are installed into homogeneous sandy or clayey foundation. This paper presents in situ tests which were performed on both single piles and pile groups, loaded to failure, with the aim of studying the pile group effect of piles embedded in multi-layered foundation. Strain gauges were installed along the shaft of 10 m long steel pipe piles, with a diameter of 143 mm. The influence of loose sand layers on the group effect in case of friction piles was evaluated. The experimental results indicated that the influence of sand layers was evident, and the group factor was calculated to be 1.237. \u0000Keywords: \u0000group efficiency; pile groups; axial capacity; load transfer.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74688686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-31DOI: 10.31814/stce.nuce2019-13(3)-02
T. Nguyen, K. Dinh
An accurate prediction of the future condition of structural components is essential for planning the maintenance, repair, and rehabilitation of bridges. As such, this paper presents an application of Artificial Neural Networks (ANN) to predict future deck condition for highway bridges in the State of Alabama, the United States. A library of 2572 bridges was extracted from the National Bridge Inventory (NBI) database and used for training, validation, and testing the ANN model, which had eight input parameters and one output being the deck rating. Specifically, the eight input parameters are Current Bridge Age, Average Daily Traffic, Design Load, Main Structure Design, Approach Span Design, Number of main Span, Percent of Daily Truck Traffic, and Average Daily Traffic Growth Rate. The results indicated the obtained ANN model can predict the condition rating of the bridge deck with an accuracy of 73.6%. If a margin error of ±1 was used, the accuracy of the proposed model reached a much higher value of 98.5%. Besides, a sensitivity analysis was conducted for individual input parameters revealed that Current Bridge Age was the most important predicting parameter of bridge deck rating. It was followed by the Design Load and Main Structure Design. The other input parameters were found to have neglectable effects on the ANN’s performance. Finally, it was shown that the obtained ANN can be used to develop the deterioration curve of the bridge deck, which helps visualize the condition rating of a deck, and accordingly the maintenance need, during its remaining service life. Keywords: condition rating; bridge deck; deterioration curve; artificial neural networks; sensitivity analysis.
{"title":"Prediction of bridge deck condition rating based on artificial neural networks","authors":"T. Nguyen, K. Dinh","doi":"10.31814/stce.nuce2019-13(3)-02","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-02","url":null,"abstract":"An accurate prediction of the future condition of structural components is essential for planning the maintenance, repair, and rehabilitation of bridges. As such, this paper presents an application of Artificial Neural Networks (ANN) to predict future deck condition for highway bridges in the State of Alabama, the United States. A library of 2572 bridges was extracted from the National Bridge Inventory (NBI) database and used for training, validation, and testing the ANN model, which had eight input parameters and one output being the deck rating. Specifically, the eight input parameters are Current Bridge Age, Average Daily Traffic, Design Load, Main Structure Design, Approach Span Design, Number of main Span, Percent of Daily Truck Traffic, and Average Daily Traffic Growth Rate. The results indicated the obtained ANN model can predict the condition rating of the bridge deck with an accuracy of 73.6%. If a margin error of ±1 was used, the accuracy of the proposed model reached a much higher value of 98.5%. Besides, a sensitivity analysis was conducted for individual input parameters revealed that Current Bridge Age was the most important predicting parameter of bridge deck rating. It was followed by the Design Load and Main Structure Design. The other input parameters were found to have neglectable effects on the ANN’s performance. Finally, it was shown that the obtained ANN can be used to develop the deterioration curve of the bridge deck, which helps visualize the condition rating of a deck, and accordingly the maintenance need, during its remaining service life. \u0000Keywords: \u0000condition rating; bridge deck; deterioration curve; artificial neural networks; sensitivity analysis.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82121784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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