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CONTENTS
Volume 81, Number 2, January25 2022
 


Abstract
This research evaluated the different types of deck to pier connections effects (one or two elastomeric bearing lines and rigid) on a concrete bridges. Three-dimensional bridge models behavior with different deck to pier connections and different distances of two bearing lines were studied under the service load. Also, the detailed connection system with two elastomeric bearing lines was modeled to evaluate the effect of changing distance between two-lines. Results indicated that the proper location of elastomeric bearings has a major impact on the transferring forces to the substructure. Double elastomeric bearing lines have a behavior between one line and rigid connections. Transferring bending moment to the substructure in two-lines is more than the corresponding value of the one line. Moreover, an increase in the distance of two-lines lead to a significant increase in the rotational stiffness of the connection, and an analytical solution was investigated for their relation. In fact, the semi-rigidity effect of this connection and its change due to the distance of bearings should be considered in the design process.

Key Words
bridge bearing; concrete bridge; elastomeric bearing; semi-rigid connection

Address
Fatemeh Shaker and Alireza Rahai: Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran

Abstract
This study highlights the accuracy of several single strut models to predict the global response of infilled reinforced concrete (R/C) frames. To this aim, six experimental tests are selected to calibrate the numerical modeling. The width of the diagonal strut is calculated using several macro models from the literature. The mechanical properties of the diagonal strut are determined by using two methods: (a) by subtracting the bare frame response from that of the infilled frame, and (b) by calculating the axial strength in the diagonal direction. A combination between the different width and the axial force models is carried out to study the effects of each parameter on global response. Non-linear pushover analyses are conducted using SAP2000. The results indicate the accuracy of the macro-modeling approach to predict the behavior of the infilled frames.

Key Words
in-plane behavior; infilled frame; macro model; masonry infill; nonlinear analyses; strut model

Address
Mohammed A. Bouarroudj and Zeineddine Boudaoud: Department of Civil Engineering, University of Larbi Ben M

Abstract
The Brace-Type Shear Fuse (BSF) device is a newly proposed steel damper with excellent cumulative ductility and stable energy dissipation. In consideration of the current situation where there are not many alternatives for transversal seismic devices used in long-span three-tower self-anchored bridges (TSSBs), this paper implements improved BSFs into the world's longest TSSB, named Jinan Fenghuang Yellow River Bridge. The new details of the BSF are developed for the TSSB, and the force-displacement hysteretic curves of the BSFs are obtained using finite element (FE) simulations. A three-dimensional refined finite element model for the research TSSB was established in SAP2000, and the effects of BSFs on dynamic characteristics and seismic response of the TSSB under different site conditions were investigated by the numerical simulation method. The results show that remarkable controlling effects of BSFs on seismic response of TSSBs under different site conditions were obtained. Compared with the case without BSFs, the TSSB installed with BSFs has mitigation ratios of the tower top displacement, lateral girder displacement, tower bending moment and tower shear force exceeding 95%, 78%, 330% and 346%, respectively. Meanwhile, BSFs have a sufficient restoring force mechanism with a minor post-earthquake residual displacement. The proposed BSFs exhibit good application prospects in long-span TSSBs.

Key Words
brace-type shear fuse; hysteretic damper; seismic performance; self-anchored suspension bridge; threetower; time history analysis

Address
Feifei Shao: Department of Civil Engineering, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya, 468-8502, Japan
Liangjiu Jia: State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, No.1239, Siping Rd., Shanghai 200092, PR China; Department of Disaster Mitigation for Structures, Tongji University, No.1239, Siping Rd., Shanghai 200092, PR China
Hanbin Ge: Department of Civil Engineering, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya, 468-8502, Japan

Abstract
This paper aimed to study the local bond-slip behavior between ultra-high-performance concrete (UHPC) and a reinforcing bar after exposure to high temperatures. A series of pull-out tests were carried out on cubic specimens of size 150x150x150 mm with deformed steel bar embedded for a fixed length of three times the diameter of the tested deformed bar. The experimental results of the bond stress-slip relationship were compared with the Euro-International Concrete Committee (CEB-Comité Euro-International du Béton)-International Federation for Prestressing (FIP-Fédération Internationale de la Précontrainte) Model Code and with prediction models found in the literature. In addition, based on the test results, an empirical model of the bond stress-slip relationship was proposed. The evaluation and comparison results showed that the modified CEBFIP Model code 2010 proposed by Aslani and Samali for the local bond stress-slip relationship for UHPC after exposure to high temperatures was more conservative. In contrast, for both room temperature and after exposure to high temperatures, the modified CEB-FIP Model Code 2010 local bond stress-slip model for UHPC proposed in this study was able to predict the test results with reasonable accuracy.

Key Words
bond strength; high temperatures; local bond stress-slip; pullout test; ultra-high-performance concrete

Address
Chao-Wei Tang: Department of Civil Engineering & Geomatics, Cheng Shiu University, No. 840, Chengching Rd., Niaosong District, Kaohsiung City, Taiwan R.O.C.; Center for Environmental Toxin and Emerging-Contaminant Research, Cheng Shiu University, No. 840, Chengching Rd., Niaosong District, Kaohsiung 83347, Taiwan; Super Micro Mass Research & Technology Center, Cheng Shiu University,
No. 840, Chengching Rd., Niaosong District, Kaohsiung 83347, Taiwan

Abstract
The bending, buckling and free vibration responses of functionally graded material (FGM) beams are investigated semi-analytically by the scaled boundary finite element method (SBFEM) in this paper. In the concepts of the SBFEM, the dimension of computational domain can be reduced by one, therefore only the axial dimension of the beam is discretized using the higher order spectral element, which reduces the amount of calculation and greatly improves the calculation efficiency. The governing equation of FGM beams is derived in detail by the means of the principle of virtual work. Compared with the higherorder beam theory, fewer parameters and simpler control equations are used. And the governing equation is transformed into a first-order ordinary differential equation by introducing intermediate variables. Analytical solutions of the governing equation can be obtained by padé series expansion in the direction of thickness. Numerical example are compared with the numerical solutions provided by the previous researchers to verify the accuracy and applicability of the proposed method. The results show that the proposed formulations can quickly converge to the reference solutions by increasing the order of higher order spectral elements, and high accuracy can be achieved by using a small number of the elements. In addition, the influence of the structural sizes, material properties and boundary conditions on the mechanical behaviors of FG beams subjected to different load types is discussed.

Key Words
bending; buckling; free vibration; functionally graded material beams; scaled boundary finite element metho

Address
Mengjie Du, Jun Liu, Wenbin Ye, Fan Yang and Gao Lin: State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China; School of Hydraulic Engineering, Faculty of Infrastructure Engineering, Dalian University of Technology, Dalian 116024, China

Abstract
This paper presents the quantification and location damage detection of plane and space truss structures in a twophase method to reduce the computations efforts significantly. In the first phase, a proposed damage indicator based on the residual force vector concept is used to get the suspected damaged members. In the second phase, using damage quantification as a variable, a teaching-learning based optimization algorithm (TLBO) is used to obtain the damage quantification value of the suspected members obtained in the first phase. TLBO is a relatively modern algorithm that has proved distinguished in solving optimization problems. For more verification of TLBO effeciency, the classical particle swarm optimization (PSO) is used in the second phase to make a comparison between TLBO and PSO algorithms. As it is clear, the first phase reduces the search space in the second phase, leading to considerable reduction in computations efforts. The method is applied on three examples, including plane and space trusses. Results have proved the capability of the proposed method to precisely detect the quantification and location of damage easily with low computational efforts, and the efficiency of TLBO in comparison to the classical PSO.

Key Words
damage detection; plane truss; residual force vector; space truss; teaching-learning optimization algorithm

Address
Osman Shallan: Department of Structural Engineering, Zagazig University, Zagazig, Egypt
Osman Hamdy: Department of Civil Engineering, Zagazig Higher Institute of Engineering & Technology, Zagazig, Egypt

Abstract
The thermodynamic properties of shaft lining concrete (SLC) are important evidence for the design and construction, and the spatial variability of concrete materials can directly affect the stochastic thermal analysis of the concrete structures. In this work, an array of field experiments of the concrete materials are carried out, and the statistical characteristics of thermophysical parameters of SLC are obtained. The coefficient of variation (COV) and scale of fluctuation (SOF) of uncertain thermophysical parameters are estimated. A three-dimensional (3-D) stochastic thermal model of concrete materials with heat conduction and hydration heat is proposed, and the uncertain thermodynamic properties of SLC are computed by the self-compiled program. Model validation with the experimental and numerical temperatures is also presented. According to the relationship between autocorrelation functions distance (ACD) and SOF for the five theoretical autocorrelation functions (ACFs), the effects of the ACF, COV and ACD of concrete materials on the uncertain thermodynamic properties of SLC are analyzed. The results show that the spatial variability of concrete materials is subsistent. The average temperatures and standard deviation (SD) of inner SLC are the lowest while the outer SLC is the highest. The effects of five 3-D ACFs of concrete materials on uncertain thermodynamic properties of SLC are insignificant. The larger the COV of concrete materials is, the larger the SD of SLC will be. On the contrary, the longer the ACD of concrete materials is, the smaller the SD of SLC will be. The SD of temperature of SLC increases first and then decreases. This study can provide a reliable reference for the thermodynamic properties of SLC considering spatial variability of concrete materials.

Key Words
concrete materials; random field; shaft lining structure; spatial variability; thermal properties

Address
Tao Wang: State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou, Jiangsu, 221116, China; State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, Sichuan, 610059, China
Shuai Li: State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou, Jiangsu, 221116, China
Xiangjun Pei: State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, Sichuan, 610059, China
Yafan Yang: State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou, Jiangsu, 221116, China
Bin Zhu: State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou, Jiangsu, 221116, China
Guoqing Zhou: State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou, Jiangsu, 221116, China

Abstract
Due to the large number of railway bridges along China's high-speed railway (HSR) lines, which cover a wide area with many lines crossing the seismic zone, the possibility of a HSR train running over a bridge when an earthquake occurs is relatively high. Since the safety performance of the train will be threatened, it is necessary to study the safety of trains running over HSR bridges during earthquakes. However, ground motion (GM) is highly random and selecting the appropriate groundmotion intensity measures (IMs) for train running safety analysis is not trivial. To deal this problem, a model of a coupled trainbridge system under seismic excitation was established and 104 GM samples were selected to evaluate the correlation between 16 different IMs and train running safety over HSR bridges during earthquakes. The results show that spectral velocity (SvT1) and displacement (SdT1) at the fundamental period of the structure have good correlation with train running safety for mediumand long-period HSR bridges, and velocity spectrum intensity (VSI) and Housner intensity (HI) have good correlation for a wide range of structural periods. Overall, VSI and HI are the optimal IMs for safety analysis of trains running over HSR bridges during earthquakes. Finally, based on VSI and HI, the IM thresholds of an HSR bridge at different speed were analyzed.

Key Words
earthquake; ground motion; intensity measure; railway bridge; running safety

Address
Xiang Liu: School of Civil Engineering, Fujian University of Technology, Fuzhou 350118, China
Lizhong Jiang: School of Civil Engineering, Central South University, Changsha 410075, China
Ping Xiang: School of Civil Engineering, Central South University, Changsha 410075, China
Yulin Feng: School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, China
Zhipeng Lai: School of Civil Engineering, Central South University, Changsha 410075, China
Xiaoyun Sun: Nanjing Vocational Institute of Transport Technology, Nanjing 211188, China

Abstract
Numerical solutions for the linear buckling behavior of thin-walled circular hollow section members (CHS) with and without longitudinal stiffeners are presented using the semi-analytical finite strip method (SAFSM) which is developed based on Marguerre's shallow shell theory and Kirchhoff's assumption. The formulation of 3-nodal line finite strip is presented. The CHS members subjected to uniform axial compression, uniform bending, and combination of compression and bending. The buckling behavior of CHS is investigated through buckling curves which relate buckling stresses to lengths of the member. Effects of longitudinal stiffeners are studied with the change of its dimensions, position, and number.

Key Words
circular hollow sections; finite strip method; Marguerre theory; shallow shell theory; stiffened cylinders; stiffened tubes

Address
Bui H. Cuong: Department of Building and Industrial Construction, Hanoi University of Civil Engineering, 55 Giai Phong, Hai Ba Trung, Hanoi, Vietnam

Abstract
In this paper, tensile behavior of joint filling has been investigated under experimental test and numerical simulation (particle flow code). Two concrete slabs containing semi cylinder hole were prepared. These slabs were attached to each other by glue and one cubic specimen with dimension of 19 cmx15 cmx6 cm was prepared. This sample placed in the universal testing machine where the direct tensile stress can be applied to this specimen by implementing a special type of load transferring device which converts the applied compressive load to that of the tensile during the test. In the present work, two different joint filling thickness i.e., 3 mm and 6 mm were prepared and tested in the laboratory to measure their direct tensile strengths. Concurrent with experimental test, numerical simulation was performed to investigate the effect of hole diameter, length of edge notch, filling thickness and filling length on the tensile behavior of joint filling. Model dimension was 19 cmx15 cm. hole diameter was change in four different values of 2.5 cm, 5 cm, 7.5 cm and 10 cm. glue lengths were different based on the hole diameter, i.e., 12.5 cm for hole diameter of 2.5 cm, 10 cm for hole diameter of 5 cm, 7.5 cm for hole diameter of 7.5 cm and 5 cm for hole diameter of 10 cm. length of edge notch were changed in three different value i.e., 10%, 30% and 50% of glue length. Filling thickness were changed in three different value of 3 mm, 6 mm and 9 mm. Tensile strengths of glue and concrete were 2.37 MPa and 6.4 MPa, respectively. The load was applied at a constant rate of 1 kg/s. Results shows that hole diameter, length of edge notch, filling thickness and filling length have important effect on the tensile behavior of joint filling. In fixed glue thinks and fixed joint length, the tensile strength was decreased by increasing the hole diameter. Comparing the results showed that the strength, failure mechanism and fracture patterns obtained numerically and experimentally were similar for both cases.

Key Words
experimental tests; joint filling; PFC2D; tensile strength

Address
Jinwei Fu: School of Civil Engineering and Transportation, North China University of Water Resources and Electric Power, Zhengzhou, 450046, China
Hadi Haeri: 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
Mohammad Fatehi Marji: Head of Mine Exploitation Engineering Department, Faculty of Mining and Metallurgy, Institution 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


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