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CONTENTS
Volume 42, Number 6, March25 2022
 

Abstract
The present research is concerned to study the effect of fractional parameter and rotation on the propagation of Rayleigh waves in an orthotropic magneto-thermoelastic media with three-phase-lags in the context of fractional order theory of generalized thermoelasticity with combined effect of rotation and hall current. The secular equations of Rayleigh waves are derived by using the appropriate boundary conditions. The wave properties such as phase velocity, attenuation coefficient are computed numerically and the numerical simulated results are presented through graphs to show the effect on all the components. Some special cases are also discussed in the present investigation.

Key Words
attenuation coefficient; fractional order; hall current; rotation; orthotropic medium; phase velocity; Rayleigh wave propagation; three-phase lags

Address
Parveen Lata and Himanshi: Department of Basic and Applied Sciences, Punjabi University, Patiala, Punjab, India

Abstract
This study proposed a robust artificial intelligence (AI) model based on the social behaviour of the imperialist competitive algorithm (ICA) and artificial neural network (ANN) for modelling the deflection of reinforced concrete beams, abbreviated as ICA-ANN model. Accordingly, the ICA was used to adjust and optimize the parameters of an ANN model (i.e., weights and biases) aiming to improve the accuracy of the ANN model in modelling the deflection reinforced concrete beams. A total of 120 experimental datasets of reinforced concrete beams were employed for this aim. Therein, applied load, tensile reinforcement strength and the reinforcement percentage were used to simulate the deflection of reinforced concrete beams. Besides, five other AI models, such as ANN, SVM (support vector machine), GLMNET (lasso and elastic-net regularized generalized linear models), CART (classification and regression tree) and KNN (k-nearest neighbours), were also used for the comprehensive assessment of the proposed model (i.e., ICA-ANN). The comparison of the derived results with the experimental findings demonstrates that among the developed models the ICA-ANN model is that can approximate the reinforced concrete beams deflection in a more reliable and robust manner.

Key Words
artificial neural network; deflection of RC beam; ICA-ANN; modelling; optimization algorithm

Address
Ning Li: School of Resource and Environment Engineering, Wuhan University of Technology, Wuhan, Hubei 430070, China

Panagiotis G. Asteris: Computational Mechanics Laboratory, School of Pedagogical and Technological Education, 14121 Heraklion, Athens, Greece

Trung-Tin Tran: Department of Information Technology, FPT University, Danang, 550000, Vietnam

Biswajeet Pradhan:Centre for Advanced Modelling and Geospatial Information Systems (CAMGIS), School of Civil and Environmental Engineering,
Faculty of Engineering & IT, University of Technology Sydney, NSW 2007, Australia/ Center of Excellence for Climate Change Research, King Abdulaziz University, P. O. Box 80234, Jeddah 21589, Saudi Arabia/ Earth Observation Centre, Institute of Climate Change, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia

Hoang Nguyen:Hanoi University of Mining and Geology, 18 Vien Street, Duc Thang Ward, Bac Tu Liem District, Hanoi 100000, Vietnam/ Innovations for Sustainable and Responsible Mining (ISRM) Research Group, Hanoi University of Mining and Geology, 18 Vien Street,
Duc Thang Ward, Bac Tu Liem District, Hanoi 100000, Vietnam

Abstract
The design codes and calculation methods related to soil–steel composite bridges and culverts only specify the minimum soil cover depth. This value is connected with the bridge span and shell height. In the case of static and dynamic loads (like passing vehicles), such approach seems to be quite reasonable. However, it is important to know how the soil cover depth affects the behaviour of soil–steel composite bridges under seismic excitation. This paper presents the results of a numerical study of soil–steel bridges with different soil cover depths (1.00, 2.00, 2.40, 3.00, 4.00, 5.00, 6.00 and 7.00 m) under seismic excitation. In addition, the same soil cover depths with different boundary conditions of the soil–steel bridge were analysed. The analysed bridge has two closed pipe-arches in its cross section. The load-carrying structure was constructed as two shells assembled from corrugated steel plate sheets, designed with a depth of 0.05 m, pitch of 0.15 m, and plate thickness of 0.003 m. The shell span is 4.40 m, and the shell height is 2.80 m. Numerical analysis was conducted using the DIANA programme based on the finite element method. A nonlinear model with El Centro records and the time history method was used to analyse the problem.

Key Words
cover depth; numerical analysis; seismic response; soil-steel bridge

Address
Tomasz Maleska: 1)Faculty of Civil Engineering and Architecture, Opole University of Technology, Katowicka 48, Opole 45-061, Poland 2)Faculty of Civil Engineering, Architecture and Environmental Engineering, Lodz University of Technology,
al. Politechniki 6, 90-924

Damian Beben:Faculty of Civil Engineering and Architecture, Opole University of Technology, Katowicka 48, Opole 45-061, Poland


Abstract
Ultra high performance concrete (UHPC) can be used in the UHPC-steel composite structures especially for bridge structures to achieve high stiffness and high fatigue resistance with low self-weight. The structural performances of UHPC-steel composite slabs subjected to hogging moment have a significant influence on the global stiffness and durability of UHPC-steel composite structures. In order to study the structural behaviors of non-steam-cured UHPC-steel composite slabs subjected to negative moment, five composite slabs combined the thin UHPC layers to steel plates via shear stud connecters with the diameter of 16mm were fabricated and tested under negative moment. The test program aimed to investigate the effect of stud spacing and longitudinal reinforcement ratios on the failure mode, load-deflection behaviors, cracking patterns, bond-slips, and carrying capacities of composite slabs subjected to negative moment. In addition, direct tensile tests for the dog-bone UHPC specimens with longitudinal reinforcement bars were carried out to study the effect of reinforcement bars on the tensile strength of UHPC in the thin structure members. Based on the experimental results, analytical models were also developed to predict the cracking load and ultimate load of UHPC-steel composite slabs subjected to negative moment.

Key Words
composite structure; cracking load; direct tensile test; negative moment; UHPC

Address
Xiao-Long Gao:1) Key Laboratory of Advanced Civil Engineering Materials, Tongji University, Ministry of Education, Shanghai 201804, China
2) College of Civil Engineering and Architecture, Henan University of Technology, Zhengzhou 450001, China

Jun-Yan Wang: Key Laboratory of Advanced Civil Engineering Materials, Tongji University, Ministry of Education, Shanghai 201804, China

Chen Bian: Key Laboratory of Advanced Civil Engineering Materials, Tongji University, Ministry of Education, Shanghai 201804, China

Ru-Cheng Xiao: College of civil engineering, Tongji University, Shanghai 200092, China

Biao Ma: Shanghai Municipal Engineering Design Institute(Group) Co., Ltd., Shanghai 200092, China

Abstract
This work presents a non-linear cylindrical bending analysis of functionally graded plate reinforced by singlewalled carbon nanotubes (SWCNTs) in thermal environment using a simple integral higher-order shear deformation theory (HSDT). This theory does not require shear correction factors and the transverse shear stresses vary parabolically through the thickness. The material properties of SWCNTs are assumed to be temperature-dependent and are obtained from molecular dynamics simulations. The material properties of functionally graded carbon nanotube-reinforced composites (FG-CNTCRs) are considered to be graded in the thickness direction, and are estimated through a micromechanical model. The non-linear strain–displacement relations in the Von Karman sense are used to study the effect of geometric non-linearity and the solution is obtained by minimization of the total potential energy. The numerical illustrations concern the nonlinear bending response of FG-CNTRC plates under different sets of thermal environmental conditions, from which results for uniformly distributed CNTRC plates are obtained as benchmarks.

Key Words
functionally graded materials; geometric non-linearity plate; integral HSDT; nanocomposites; thermal environment

Address
Nassira Djilali: Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria

Abdelmoumen Anis Bousahla: Laboratoire de Modélisation et Simulation Multi-échelle, Université de Sidi Bel Abbés, Algeria

Abdelhakim Kaci: Université Dr Tahar Moulay, Faculté de Technologie, Département de Génie Civil et Hydraulique, BP 138Cité En-Nasr 20000 Saida, Algérie

Mahmoud M. Selim: Department of Mathematics, Al-Aflaj College of Science and Humanities, Prince Sattam bin Abdulaziz University,
Al-Aflaj 710-11912 Saudi Arabia

Fouad Bourada: épartement des Sciences et de la Technologie, Université de Tissemsilt, BP 38004 Ben Hamouda, Algérie

Abdeldjebbar Tounsi: Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria

Abdelouahed Tounsi: 1)Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria 2)YFL (Yonsei Frontier Lab), Yonsei University, Seoul, Korea 3)Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals, 31261 Dhahran, Eastern Province, Saudi Arabia
4)Interdisciplinary Research Center for Construction and Building Materials, KFUPM, Dhahran, Saudi Arabia

Kouider Halim Benrahou:Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria

S.R. Mahmoud: GRC Department, Applied College, King Abdulaziz University, Jeddah 21589, Saudi Arabia

Abstract
As a type of semi-rigid connection, the top and seat angle connections are popular in current structures owing to their good cyclic performance and simple erection. However, their stiffness and load bearing capacity are relatively insufficient. This study proposes two strengthening methods to further increase the stiffness and strength of bolted-angle joints while maintaining satisfactory energy dissipation capacity (EDC) and ductility. Cyclic loading tests were conducted on six joint specimens with different strengthened angle components. Based on the test results, the influence of the following important factors on the cyclic behavior of steel joint specimens was investigated: the position of the rib stiffeners (edge rib stiffeners and middle rib stiffener), steel strength grade of rib stiffeners (Q345 and Q690), and additional stiffeners or not. In addition, the finite element models of these specimens were built and validated through a comparison of experimental and numerical results. The stiffness and bearing capacity of the bolted-angle joints could be improved significantly by utilizing the novel strengthened joints proposed in this study. Moreover, this can be achieved with almost no increase in the amount of steel required, and the EDC of this joint could also satisfy the requirements of seismic codes from various countries.

Key Words
beam-to-column connection; cyclic test; finite element analysis; hysteresis behavior; strengthened angle components

Address
Lan Kang:State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou,
Guangdong Province, 510641, People

Cheng Zhang: School of Civil Engineering and Transportation, South China University of Technology, Guangzhou,
Guangdong Province, 510641, People

Abstract
The free and live load-forced vibration behaviour of porous functionally graded (PFG) higher order nanobeams in the thermal and magnetic fields is investigated comprehensively through this work in the framework of nonlocal strain gradient theory (NLSGT). The porosity effects on the dynamic behaviour of FG nanobeams is investigated using four different porosity distribution models. These models are exploited; uniform, symmetrical, condensed upward, and condensed downward distributions. The material characteristics gradation in the thickness direction is estimated using the power-law. The magnetic field effect is incorporated using Maxwell's equations. The third order shear deformation beam theory is adopted to incorporate the shear deformation effect. The Hamilton principle is adopted to derive the coupled thermomagnetic dynamic equations of motion of the whole system and the associated boundary conditions. Navier method is used to derive the analytical solution of the governing equations. The developed methodology is verified and compared with the available results in the literature and good agreement is observed. Parametric studies are conducted to show effects of porosity parameter; porosity distribution, temperature rise, magnetic field intensity, material gradation index, non-classical parameters, and the applied moving load velocity on the vibration behavior of nanobeams. It has been showed that all the analyzed conditions have significant effects on the dynamic behavior of the nanobeams. Additionally, it has been observed that the negative effects of moving load, porosity and thermal load on the nanobeam dynamics can be reduced by the effect of the force induced from the directed magnetic field or can be kept within certain desired design limits by controlling the intensity of the magnetic field.

Key Words
coupled field problem; different porosity distribution models; FG porous nanobeams; Navier analytical methodology; thermal and magnetic fields; vibration of moving load

Address
Ismail Esen: Department of Mechanical Engineering, Karabuk University, Karabuk, Turkey

Mashhour A. Alazwari:Mechanical Engineering Department, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah, Saudi Arabia

Mohamed A Eltaher: 1)Mechanical Engineering Department, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah, Saudi Arabia
2) Mechanical Design and Production Department, Faculty of Engineering, Zagazig University, P.O. Box 44519, Zagazig, Egypt

Alaa A. Abdelrahman:Mechanical Design and Production Department, Faculty of Engineering, Zagazig University, P.O. Box 44519, Zagazig, Egypt

Abstract
The rotation capacities of the plastic hinges located at beam-ends are significantly reduced in traditional steel framed-tube structures (SFTSs) because of the small span-to-depth ratios of the deep beams, leading to the low ductility and energy dissipation capacities of the SFTSs. High-strength steel framed-tube structures with replaceable shear links (HSSFTSRSLs) are proposed to address this issue. A replaceable shear link is located at the mid-span of a deep spandrel beam to act as a ductile fuse to dissipate the seismic energy in HSSFTS-RSLs. A 2/3-scaled HSSFTS-RSL specimen with a shear link fabricated of high-strength low-alloy Q355 structural steel was created, and a cyclic loading test was performed to study the hysteresis behaviors of this specimen. The test results were compared to the specimens with soft steel shear links in previous studies to investigate the feasibility of using high-strength low-alloy steel for shear links in HSSFTS-RSLs. The effects of link web stiffener spaces on the cyclic performance of the HSSFTS-RSLs with Q355 steel shear links were investigated based on the nonlinear numerical analysis. The test results indicate that the specimen with a Q355 steel shear link exhibited a reliable and stable seismic performance. If the maximum interstory drift of HSSFTS-RSL is designed lower than 2% under earthquakes, the HSSFTS-RSLs with Q355 steel shear links can have similar seismic performance to the structures with soft steel shear links, even though these shear links have similar shear and flexural strength. For the Q355 steel shear links with web height-tothickness ratios higher than 30.7 in HSSFTS-RSLs, it is suggested that the maximum intermediate web stiffener space is decreased by 15% from the allowable space for the shear link in AISC341-16 due to the analytical results.

Key Words
cyclic behaviors; high-strength low-alloy steel; high strength steel; numerical analysis; steel framed-tube structures

Address
Yan Guo: School of Civil and Geodesy Engineering, Shaanxi College of Communication Technology, Xi'an 710018, China

Ming Lian: 1) School of Civil Engineering, Xi'an University of Architecture & Technology, Xian 710055, China
2) Key Lab of Structural Engineering and Earthquake Resistance, Ministry of Education (XAUAT), Xi'an 710055, China

Hao Zhang: School of Civil Engineering, Xi'an University of Architecture & Technology, Xian 710055, China

Qianqian Cheng:School of Civil Engineering, Xi'an University of Architecture & Technology, Xian 710055, China

Abstract
The fatigue behavior of welded open rib-to crossbeam joints (ORCJ) in orthotropic bridge structures is investigated using a traction structural stress method. The fatigue behaviors of welded open rib-to crossbeam joints have been a subject of study for decades for ensuring operational safety and future design improvement. A mesh-insensitive combination of traction structural stresses in ORCJ was obtained considering the effect of in-plane shear stress and validated by fatigue test results. The proposed method is advantageous for predicting fatigue cracks that initiate from the crossbeam cutout and propagate along the crossbeam. The investigations carried out with the proposed approach reveal that the normal structural stress decreases with the propagation of fatigue cracks, while the ratio of shear stress to normal stress increases. The effect of shear structural stress is significant for the analysis of fatigue behavior of ORCJ in multiaxial stress states.

Key Words
orthotropic steel bridges with open ribs; multiaxial stress state; in-plane shear structural stress; a combination of traction structural stresses

Address
Haibo Yang: 1)College of Water Conservancy and Civil Engineering, Shandong Agricultural University, Shandong, China 2)School of Ocean Engineering, Harbin Institute of Technology at Weihai, Weihai, China, 264200

Hongliang Qian: School of Ocean Engineering, Harbin Institute of Technology at Weihai, Weihai, China, 264200

Ping Wang: School of Ocean Engineering, Harbin Institute of Technology at Weihai, Weihai, China, 264200

Pingsha Dong: Department of Mechanical Engineering, University of Michigan, Ann Arbor 48109, USA

Fillipo Berto: Department of Engineering Design and Materials, Norwegian University of Science and Technology, Trondheim, Norway

Abstract
Due to limited resources, and increasing speed of development, the optimal use of available resources has become the most important challenge of human societies. In the last few decades, many researchers have focused their research on solving various optimization problems, providing new optimization methods, and improving the performance of existing optimization methods. Echolocation Search Algorithm (ESA) is an evolutionary optimization algorithm that is based on mimicking the mechanism of the animals such as bats, dolphins, oilbirds, etc in food finding to solve optimization problems. In this paper, the ability of ESA for solving truss size optimization problems with continuous variables is investigated. To examine the efficiency of ESA, three benchmark examples are considered. The numerical results exhibit the effectiveness of ESA for solving truss optimization problems.

Key Words
ESA; evolutionary optimization algorithm; structural optimization; truss

Address
Mehdi Nobahari:Department of Civil Engineering, Neyshabur Branch, Islamic Azad University, Neyshabur, Iran

Nafise Ghabdiyan:Department of Mathematics, Neyshabur Branch, Islamic Azad University, Neyshabur, Iran

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