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CONTENTS
Volume 81, Number 1, January10 2022
 


Abstract
Due to the frequency and magnitude of some loads produced by gusts of turbulent wind, building floors can develop lateral displacements and significant accelerations which can produce strong inertial forces on structural, non-structural elements and occupants. A device that can help to reduce the floor accelerations is the well-known Tuned Mass Damper (TMD); however, nowadays there is no enough information about its capacity in order to dissipate energy of turbulent wind loads. For this reason, in this paper different buildings with and without TMD are modeled and dynamically analyzed under simulated wind loads in order to study the reduction of peak floor accelerations. The results indicate that peak floor accelerations can be reduced up to 40% when TMD are incorporated in the buildings, which demonstrated that the Tuned Mass Damper is an efficient device to reduce the wind effects on tall buildings.

Key Words
dynamic response; peak floor accelerations; simulated wind loads; tuned mass damper; wind response

Address
Juan Acosta, Edén Bojórquez, Juan Bojórquez, Alfredo Reyes-Salazar: Facultad de Ingeniería, Universidad Autónoma de Sinaloa, Calzada de las Américas y B. Universitarios s/n, C.P. 80040, Culiacán, Sinaloa, México
Omar Payán: Department of Mechanical and Mechatronic Engineering, Tecnologico Nacional de Mexico Campus Culiacan, Culiacan, Sinaloa, Mexico
Manuel Barraza: Department of Mechanical and Mechatronic Engineering, Tecnológico Nacional de México Campus Culiacán, Culiacán, Sinaloa, México
Juan Serrano: Facultad de Ingeniería, Arquitectura y Diseño, Universidad Autónoma de Baja California, Ensenada 22860, México

Abstract
This paper considers the combination of cyclic and axial loads to investigate the hysteretic performance of Hsection 6061-T6 aluminum alloy members. The hysteretic performance of aluminum alloy members is the basis for the seismic performance of aluminum alloy structures. Despite the prevalence of aluminum alloy reticulated shells structures worldwide, research into the seismic performance of aluminum alloy structures remains inadequate. To address this deficiency, we design and conduct cyclic axial load testing of three H-section members based on a reliable testing system. The influence of slenderness ratios and bending direction on the failure form, bearing capacity, and stiffness degradation of each member are analyzed. The experiment results show that overall buckling dominates the failure mechanism of all test members before local buckling occurs. As the load increases after overall buckling, the plasticity of the member develops, finally leading to local buckling and fracture failure. The results illustrate that the plasticity development of the local buckling position is the main reason for the stiffness degradation and failure of the member. Additionally, with the increase of the slenderness ratio, the energy-dissipation capacity and stiffness of the member decrease significantly. Simultaneously, a finite element model based on the Chaboche hybrid strengthening model is established according to the experiment, and the rationality of the constitutive model and validity of the finite element simulation method are verified. The parameter analysis of twenty-four members with different sections, slenderness ratios, bending directions, and boundary conditions are also carried out. Results show that the section size and boundary condition of the member have a significant influence on stiffness degradation and energy dissipation capacity. Based on the above, the appropriate material constitutive relationship and analysis method of H-section aluminum alloy members under cyclic loading are determined, providing a reference for the seismic design of aluminum alloy structures.

Key Words
axial cyclic loading; H-section member aluminum alloy member; hysteretic performance; numerical analysis; seismic analysis

Address
Jinzhi Wu: Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, PR China; The Key Laboratory of Urban Security and Disaster Engineering, MOE, Beijing University of Technology, Beijing 100124, PR China
Jianhua Zheng: Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, PR China
Guojun Sun: Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, PR China; The Key Laboratory of Urban Security and Disaster Engineering, MOE, Beijing University of Technology, Beijing 100124, PR China
Xinquan Chang: Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, PR China

Abstract
The present paper deals with the application of one dimensional piezoelectric materials in particular piezo-thermoelastic nanobeam. The generalized piezo-thermoelastic theory with two temperature and Euler Bernoulli theory with small scale effects using nonlocal Eringen's theory have been used to form the mathematical model. The ends of nanobeam are considered to be simply supported and at a constant temperature. The mathematical model so formed is solved to obtain the nondimensional expressions for lateral deflection, electric potential, thermal moment, thermoelastic damping and frequency shift. Effect of frequency and nonlocal parameter on the lateral deflection, electric potential, thermal moment with generalized piezothermoelastic theory are represented graphically using the MATLAB software. Comparisons are made with the different theories of thermoelasticity.

Key Words
generalized piezothermoelastic theory; nanobeam; nonlocal; piezo-thermo-elastic; time harmonic frequency; transversely Isotropic

Address
Iqbal Kaur: Government College for Girls, Palwal, Kurukshetra, Haryana, India; Department of Basic and Applied Sciences, Punjabi University, Patiala, Punjab, India
Parveen Lata: Department of Basic and Applied Sciences, Punjabi University, Patiala, Punjab, India
Kulvinder Singh: UIET, Kurukshetra University, Kurukshetra, India

Abstract
Layer separation (delamination) is an essential threat to fiber-reinforced polymer (FRP) plates under dynamic, static, and fatigue loads. Under compressive load, the growth of delamination will lead to structural instability. The aim of this paper is to present a method using shape memory alloy (SMA) stitches to suppress the delamination growth in a FRP plate and to improve the buckling behavior of the plate with a rectangular hole. The present paper is divided into two parts. Firstly, a closedform (CF) formulation for evaluating the buckling load of the FRP plate is presented. Secondly, the finite element method (FEM) will be employed to calculate the buckling loads of the plates which serves to validate the results obtained from the closed-form method. The novelty of this work is the development of the closed-form solution using the p-Ritz energy approach regarding the stress-dependent phase transformation of SMA to trace the equilibrium path. For the FEM, the Lagoudas constitutive model of the SMA material is implemented in FORTRAN programming language using a user material subroutines (VUMAT). The model is simulated in ABAQUS/Explicit solver due to the nature of the loading type. The cohesive zone model (CZM) is applied to simulate the delamination growth.

Key Words
buckling; Cohesive zone model; delamination; FEM; FRP; P-Ritz energy method; rectangular hole; shape memory alloy; stitches

Address
Ghazaleh Soltanieh: Department of Building and Real Estate, The Hong Kong Polytechnic University, Hong Kong, China
Michael CH. Yam, Jing-Zhou Zhang: The Chinese National Engineering Research Center (CNERC), Hong Kong, China
Ke Ke: Key Laboratory of New Technology for Construction of Cities in Mountain Area, School of Civil Engineering, Chongqing University, Chongqing, China

Abstract
The problem of optimal stochastic GA control of the system with uncertain parameters and unsure noise covariates is studied. First, without knowing the explicit form of the dynamic system, the open-loop determinism problem with path optimization is solved. Next, Gaussian linear quadratic controllers (LQG) are designed for linear systems that depend on the nominal path. A robust genetic neural network (NN) fuzzy controller is synthesized, which consists of a Kalman filter and an optimal controller to assure the asymptotic stability of the discrete control system. A simulation is performed to prove the suitability and performance of the recommended algorithm. The results indicated that the recommended method is a feasible method to improve the performance of active tuned mass damper (ATMD) shear buildings under random earthquake disturbances.

Key Words
genetic algorithm; Lyapunov; modified adaptive law; neural network controller; Stability theory

Address
Z.Y. Chen: School of Science, Guangdong University of Petrochem Technology, Maoming 525000, PR China
Sheng-Hsiang Peng: Department of Civil and Environmental Engineering, University of California, Irvine, CA, 92697, USA
Ruei-Yuan Wang, Yahui Meng: School of Science, Guangdong University of Petrochem Technology, Maoming 525000, PR China
Qiuli Fu: School of Computer Science, Guangdong University of Petrochem Technology, Maoming 525000, PR China
Timothy Chen: Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA

Abstract
Prestressed prefabricated hollow core concrete slabs with spans of 5 m and 10 m are commonly used since last century and still in service due to the advantage of construction convenience and durability. However, the end slabs are regularly subjected to cracks at the top and fail with brittleness due to the asymmetric boundary conditions. To better maintain such widely used type of hollow core slabs, the effect of asymmetric constraint in the end slabs are systematically studied through detailed nonlinear finite element analyses and experimental data. Experimental tests of slabs with four prestressed tendons and seven prestressed tendons with different boundary conditions were conducted. Results observe three failure modes of the slabs: the bending failure mode, shear and torsion failure mode, and transverse failure mode. Detailed nonlinear finite element models are developed to well match the failure modes and to reveal potential damage scenarios with asymmetric boundary conditions. Recommendations regarding ultimate capacity of the slabs with asymmetric boundary conditions are made to ensure a safe and rational design of prestressed concrete hollow slabs for short span bridges.

Key Words
asymmetric boundary conditions; cracks; finite element analysis; precast hollow core; prestressed tendons

Address
Haiying Ma: Department of Bridge Engineering, Tongji University, Shanghai, 200092, China
Minghui Lai: Sichuan Highway Planning, Survey, Design and Research Institute Ltd., Chengdu,610041, China
Ye Xia: Department of Bridge Engineering, Tongji University, Shanghai, 200092, China

Abstract
The dynamic responses of a pier-pile-soil system subjected to a barge/flotilla collision are analyzed. A coupled highspeed train and bridge system with a damaged pier after barge/flotilla collision is established by taking the additional unevenness of the track induced by the damaged pier as the self-excitation of the system. The whole process of a CRH2 high-speed train running on the 6x32 m simply-supported PC (prestressed concrete) box-girder bridge with a damaged pier is simulated as a case study. The results show that the lateral displacements and accelerations of the bridge with a damaged pier are much greater than the ones before the collision. The running safety indices of the train increase with the train speed as well as with the number of barges in the flotilla. In flotilla collision, the lateral wheel/rail forces of the train exceed the allowable values at a certain speed, which influences the running safety of the trains.

Key Words
dynamic response; flotilla collision; high-speed railway; reinforced concrete pier; running safety; trainbridge- subsoil model

Address
Chaoyi Xia: School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China
Kunpeng Wang: CCCC Highway Bridges National Engineering Research Center Co., Ltd., Beijing 100120, China
Jiacheng Huang, He Xia: School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China
Lin Qi: Tess, RTRI, Kokubunji-shi, Tokyo 184-8540, Japan
Xuan Wu: School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China

Abstract
The effects of interaction between concrete-gypsum interface and edge crack on the failure behavior of the specimens in senicircular bend (SCB) test were studied in the laboratory and also simulated numerically using the discrete element method. Some quarter circular specimens of gypsum and concrete with 5 cm radii and hieghts were separately prepared. Then the semicircular testing specimens were made by attaching one gypsum and one concrete sample to one another using a special glue and one edge crack is produced (in the interface) by do not using the glue in that part of the interface. The tensile strengths of concrete and gypsum samples were separately measured as 2.2 MPa and 1.3 MPa, respectively. during all testing performances a constant loading rate of 0.005 mm/s were stablished. The proposed testing method showed that the mechanism of failure and fracture in the brittle materials were mostly governed by the dimensions and number of discontinuities. The fracture toughnesses of the SCB samples were related to the fracture patterns during the failure processes of these specimens. The tensile behaviour of edge notch was related to the number of induced tensile cracks which were increased by decreasing the joint length. The fracture toughness of samples was constant by increasing the joint length. The failure process and fracture pattern in the notched semi-circular bending specimens were similar for both methods used in this study (i.e., the laboratory tests and the simulation procedure using the particle flow code (PFC2D)).

Key Words
fracture toughness; gypsum-concrete interface; interface angularities; joint length; PFC2D; Semi Circular Bend Test

Address
Jinwei Fu: School of Civil Engineering and Transportation, North China University of Water Resources and Electric Power, Zhengzhou,450046, China
Vahab Sarfarazi: Department of Mining Engineering, Hamedan University of Technology, Hamedan, Iran
Hadi Haeri: State Key Laboratory for Deep GeoMechanics and Underground Engineering, Beijing, 100083, China
Mohammad Fatehi Marji: Department of Mine Exploitation Engineering, Faculty of Mining and metallurgy, Institute of Engineering, Yazd University, Yazd, Iran
Mengdi Guo: School of Civil Engineering and Transportation, North China University of Water Resources and Electric Power, Zhengzhou,450046, China

Abstract
The optimum design of reinforced concrete cantilever retaining walls subjected to seismic loads is an extremely important challenge in structural and geotechnical engineering, especially in seismic zones. This study proposes an adaptive sperm swarm optimization algorithm (ASSO) for economic design of retaining structure under static and seismic loading. The proposed ASSO algorithm utilizes a time-varying velocity damping factor to provide a fine balance between the explorative and exploitative behavior of the original method. In addition, the new method considers a reasonable velocity limitation to avoid the divergence of the sperm movement. The proposed algorithm is benchmarked with a set of test functions and the results are compared with the standard sperm swarm optimization (SSO) and some other robust metaheuristic from the literature. For seismic optimization of retaining structures, Mononobe-Okabe method is employed for dynamic loading conditions and total construction cost of the structure is considered as the single objective function. The optimization constraints include both geotechnical and structural restrictions and the design variables are the geometrical dimensions of the wall and the amount of steel reinforcement. Finally, optimization of two benchmark retaining structures under static and seismic loads using the ASSO algorithm is presented. According to the numerical results, the ASSO may provide better optimal solutions, and the designs obtained by ASSO have a lower cost by up to 20% compared with some other methods from the literature.

Key Words
minimum cost; retaining wall; seismic load; sperm swarm; static load

Address
Mohammad Khajehzadeh: Department of Civil Engineering, Anar Branch, Islamic Azad University, Anar, Iran
Amir Kalhor: Faculty of Civil Engineering, Islamic Azad University, Shal Branch, Shal, Iran
Mehran Soltani Tehrani: Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
Mohammadreza Jebeli: Department of Civil Engineering, Sharif University of Technology, Tehran, Iran

Abstract
The prediction error variances for frequencies are usually considered as unknown in the Bayesian system identification process. However, the error variances for mode shapes are taken as known to reduce the dimension of an identification problem. The present study attempts to explore the effectiveness of Bayesian approach of model parameters updating using Markov Chain Monte Carlo (MCMC) technique considering the prediction error variances for both the frequencies and mode shapes. To remove the ergodicity of Markov Chain, the posterior distribution is obtained by Gaussian Random walk over the proposal distribution. The prior distributions of prediction error variances of modal evidences are implemented through inverse gamma distribution to assess the effectiveness of estimation of posterior values of model parameters. The issue of incomplete data that makes the problem ill-conditioned and the associated singularity problem is prudently dealt in by adopting a regularization technique. The proposed approach is demonstrated numerically by considering an eight-storey frame model with both complete and incomplete modal data sets. Further, to study the effectiveness of the proposed approach, a comparative study with regard to accuracy and computational efficacy of the proposed approach is made with the Sequential Monte Carlo approach of model parameter updating.

Key Words
Bayesian updating; error variances; Markov Chain Monte Carlo; modal data; sequential Monte Carlo

Address
Partha Sengupta and Subrata Chakraborty: Department of Civil Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India


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