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Abstract
In order to analyze the vibration control effect of viscous damper in the concrete archaized buildings with lintel-column joints under seismic action, 3 specimens were tested under dynamic excitation. Two specimens with viscous damper were defined as the controlled component and one specimen without viscous damper was specified as the non-controlled component. The loading process and failure patterns were obtained from the test results. The failure characteristics, skeleton curves and mechanical behavior such as the load-displacement hysteretic loops, load carrying capacity, degradation of strength and rigidity, ductility and energy dissipation of the joints were analyzed. The results indicate that the load-bearing capacity of the controlled component is significantly higher than that of the non-controlled component. The former component has an average increase of 27.4% in yield load and 22.4% in ultimate load, respectively. Meanwhile, the performance of displacement ductility and the ability of energy dissipation for the controlled component are superior to those of the non-controlled component as well. Compared with non-controlled component, equivalent viscous damping coefficients are improved by 27.3%-30.8%, the average increase is 29.0% at ultimate load for controlled component. All these results reflect that the seismic performance of the controlled component is significantly better than that of the non-controlled component. These researches are helpful for practical application of viscous damper in the concrete archaizing buildings with lintel-column joints.

Key Words
archaized buildings; dynamic test; seismic behavior; viscous damper

Address
Jianyang Xue, Jinshuang Dong and Yan Sui:School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi, China

Abstract
When eccentrically braced steel frames (EBFs) are in the desired failure mode, links yield at each layer and column bases appear plastically hinged. Traditional design methods cannot accurately predict the inelastic behavior of structures owing to the use of capacity-based design theory. This paper proposes the use of performance-based seismic design (PBSD) method for planning eccentrically braced frames. PBSD can predict and control inelastic deformation of structures by target drift and failure mode. In buildings designed via this process, all links dissipate energy in the rare event of an earthquake, while other members remain in elastic state, and as the story drift is uniform along the structure height, weak layers will be avoided. In this condition, eccentrically braced frames may be more easily rehabilitated after the effects of an earthquake. The effectiveness of the proposed method is illustrated through a sample case study of ten-story K-type EBFs and Y- type EBFs buildings, and is validated by pushover analysis and dynamic analysis. The ultimate state of frames designed by the proposed method will fail in the desired failure mode. That is, inelastic deformation of structure mainly occurs in links; each layer of links involved dissipates energy, and weak layers do not exist in the structure. The PBSD method can provide a reference for structural design of eccentrically braced steel frames.

Key Words
performance-based seismic design; eccentrically braced steel frames; failure mode; link; weak layer

Address
Shen Li, Jian-bo Tian and Yun-he Liu: School of Civil Engineering and architecture, Xi\'an University of Technology, Xi\'an Beilin District Jinhua Road No. 5, 710048, P. R. China

Abstract
This paper develops a new method for analyzing the structural seismic behavior of single-layer reticulated shells based on exponential strain energy density (ESED). The ESED method reveals a characteristic point from a relationship between ESED sum and peak seismic acceleration. Then, the characteristic point leads to an updated concept of structural failure and an ESED-based criterion for predicting structural failure load. Subsequently, the ESED-based criterion and the characteristic point are verified through numerical analysis of typical single-layer reticulated shells with different configurations and a shaking table test of the scale shell model. Finally, discussions further verify the rationality and application of the ESED-based criterion. The ESED method might open a new way of structural analysis and the ESED-based criterion might indicate a prospect for a unified criterion for predicting seismic failure loads of various structures.

Key Words
ESED method; ESED-based criterion; failure load; single-layer spherical shell; characteristic point

Address
Ming Zhang: School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China Guangchun Zhou: School of Civil Engineering, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China Yanxia Huang: School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China Xudong Zhi: School of Civil Engineering, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China De-Yi Zhang: School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China

Abstract
This work derives a generalized time fractional differential equation governing wave propagation in a radially vibrating non-classical cylindrical medium. The cylinder is made of a transversely isotropic hyperelastic John\'s material which obeys frequency-dependent power law attenuation. Employing the definition of the conformable fractional derivative, the solution of the obtained generalized time fractional wave equation is expressed in terms of product of Bessel functions in spatial and temporal variables; and the resulting wave is characterized by the presence of peakons, the appearance of which fade in density as the order of fractional derivative approaches 2. It is obtained that the transversely isotropic structure of the material of the cylinder increases the wave speed and introduces an additional term in the wave equation. Further, it is observed that the law relating the non-zero components of the Cauchy stress tensor in the cylinder under consideration generalizes the hypothesis of plane strain in classical elasticity theory. This study reinforces the view that fractional derivative is suitable for modeling anomalous wave propagation in media.

Key Words
fractional wave; non-classical cylinder; radial vibration

Address
Odunayo O. Fadodun, Olawanle P. Layeni and Adegbola P. Akinola: Department of Mathematics, Obafemi Awolowo University, Ile-Ife, 220005, Nigeria

Abstract
The objective of this paper is to report on a study of the use of unstiffened thin steel plate shear walls (SPSWs) for the seismic performance improvement of reinforced concrete frames with deficient lateral rigidity. The behaviour of reinforced concrete frames during seismic activities was rehabilitated with an alternative and occupant-friendly retrofitting scheme. The study involved tests of eight 1/3 scale, one bay, two storey test specimens under cyclic quasi-static lateral loadings. The first specimen, tested in previous test program, was a reference specimen, and in seven other specimens, steel infill plates were used to replace the conventional infill brick or the concrete panels. The identification of the load-deformation characteristics, the determination of the level of improvement in the overall strength, and the elastic post-buckling stiffness were the main issues investigated during the quasi-static test program. With the introduction of the SPSWs, it was observed that the strength, stiffness and energy absorption capacities were significantly improved. It was also observed that the experimental hysteresis curves were stable, and the composite systems showed excellent energy dissipation capacities due to the formation of a diagonal tension field action along with a diagonal compression buckling of the infill plates.

Key Words
steel plate; lateral rigidity; earthquake; rehabilitation; reinforced concrete frame

Address
Hasan H. Korkmaz and Ali S. Ecemis: Engineering Faculty, Civil Engineering Department, Selcuk University, Konya, Turkey

Abstract
The behavior of 8 steel reinforced high-strength concrete (SRHSC) columns, which comprised of four identical columns with cross-shaped steel and other four identical columns with square steel tube, was investigated experimentally under cyclic uniaxial and biaxial loading independently. The influence of steel configuration and loading path on the global behavior of SRHSC columns in terms of failure process, hysteretic characteristics, stiffness degradation and ductility were investigated and discussed, as well as stress level of the longitudinal and transverse reinforcing bars and steel. The research results indicate that with a same steel ratio deformation capacity of steel reinforced concrete columns with a square steel tube is better than the one with a cross-shaped steel. Loading path affects hysteretic characteristics of the specimens significantly. Under asymmetrical loading path, hysteretic characteristics of the specimens are also asymmetry. Compared with specimens under unidirectional loading, specimens subjected to bidirectional loading have poor carrying capacity, fast stiffness degradation, small yielding displacement, poor ductility and small ultimate failure drift. It also demonstrates that loading paths affect the deformation capacity or deformation performance significantly. Longitudinal reinforcement yielding occurs before the peak load is attained, while steel yielding occurs at the peak load. During later displacement loading, strain of longitudinal and transverse reinforcing bars and steel of specimens under biaxial loading increased faster than those of specimens subjected to unidirectional loading. Therefore, the bidirectional loading path has great influence on the seismic performance such as carrying capacity and deformation performance, which should be paid more attentions in structure design.

Key Words
steel reinforced concrete columns; high-strength concrete; bidirectional loading; coupling effect; seismic behavior

Address
Peng Wang, Qing X. Shi, Feng Wang and Qiu W. Wang: School of Civil Engineering, Xi\'an University of Architecture & Technology, No.13, Yanta Road, Xi\'an, Shaanxi, China

Abstract
Flooding induced scour has been long recognized as a major hazard to river-crossing bridges. Many studies in recent years have attempted to evaluate the effects of scour on the seismic performance of bridges, and probabilistic frameworks are usually adopted. However, direct and straightforward insight about how foundation scour affects bridges as a type of soil-foundation-structure system is usually understated. In this paper, we provide a comprehensive review of applied methods centering around seismic assessment of scoured bridges considering soil-foundation-structure interaction. When introducing these applied analysis and modeling methods, a simple bridge model is provided to demonstrate the use of these methods as a case study. Particularly, we propose the use of nonlinear modal pushover analysis as a rapid technique to model scoured bridge systems, and numerical validation and application of this procedure are given using the simple bridge model. All methods reviewed in this paper can serve as baseline components for performing probabilistic vulnerability or risk assessment for any river-crossing bridge system subject to flood-induced scour and earthquakes.

Key Words
bridge scour; multi-hazard analysis; soil-foundation-structure interaction; foundation impedance; seismic effects; nonlinear modal pushover analysis

Address
Xuan Guo: Department of Civil Engineering, Yangzhou University, Yangzhou, China Mostafa Badroddin and ZhiQiang Chen: Department of Civil and Mechanical Engineering, University of Missouri-Kansas City, Missouri, USA

Abstract
The objective of the present paper is to investigate the bending behavior with stretching effect of carbon nanotubereinforced composite (CNTRC) beams. The beams resting on the Pasternak elastic foundation, including a shear layer and Winkler spring, are considered. The single-walled carbon nanotubes (SWCNTs) are aligned and distributed in polymeric matrix with different patterns of reinforcement. The material properties of the CNTRC beams are estimated by using the rule of mixture. The significant feature of this model is that, in addition to including the shear deformation effect and stretching effect it deals with only 4 unknowns without including a shear correction factor. The single-walled carbon nanotubes (SWCNTs) are aligned and distributed in polymeric matrix with different patterns of reinforcement. The material properties of the CNTRC beams are assessed by employing the rule of mixture. The equilibrium equations have been obtained using the principle of virtual displacements. The mathematical models provided in this paper are numerically validated by comparison with some available results. New results of bending analyses of CNTRC beams based on the present theory with stretching effect is presented and discussed in details. the effects of different parameters of the beam on the bending responses of CNTRC beam are discussed.

Key Words
bending; stretching effect; CNTRC beams; elastic foundation

Address
Lazreg Hadji: Department of Civil Engineering, Ibn Khaldoun University, BP 78 Zaaroura, 14000 Tiaret, Algeria; Laboratory of Geomatics and Sustainable Development, Ibn Khaldoun University of Tiaret, Algeria Nafissa Zouatnia: Department of Civil Engineering, Laboratory of Structures, Geotechnics and Risks (LSGR), Hassiba Benbouali University of Chlef, Algeria, BP 151, Hay Essalam, UHB Chlef, Chlef (02000), Algeria Mohamed Ait Amar Meziane: Department of Civil Engineering, Ibn Khaldoun University, BP 78 Zaaroura, 14000 Tiaret, Algeria Amar Kassoul: Department of Civil Engineering, Laboratory of Structures, Geotechnics and Risks (LSGR), Hassiba Benbouali University of Chlef, Algeria, BP 151, Hay Essalam, UHB Chlef, Chlef (02000), Algeria

Abstract
The surrounding rocks of underground openings are natural materials and their mechanical behavior under seismic load is different from traditional man-made materials. This paper proposes a framework to comprehensively model the mechanical behavior of surrounding rocks. Firstly, the effects of seismic load on the surrounding rocks are summarized. Three mechanical effects and the mechanism, including the strengthening effect, the degradation effect, and the relaxation effect, are detailed, respectively. Then, the framework for modelling the mechanical behavior of surrounding rocks are outlined. The straindependent characteristics of rocks under seismic load is considered to model the strengthening effect. The damage concept under cyclic load is introduced to model the degradation effect. The quantitative relationship between the damage coefficient and the relaxation zone is established to model the relaxation effect. The major effects caused by seismic load, in this way, are all considered in the proposed framework. Afterwards, an independently developed 3D dynamic FEM analysis code is adopted to include the algorithms and models of the framework. Finally, the proposed framework is illustrated with its application to an underground opening subjected to earthquake impact. The calculation results and post-earthquake survey conclusions are seen to agree well, indicating the effectiveness of the proposed framework. Based on the numerical calculation results, post-earthquake reinforcement measures are suggested.

Key Words
rock material; material strengthening; material degradation; relaxation zone; earthquake effect; numerical analysis

Address
Yuting Zhang, Xiuli Ding, Shuling Huang, Qitao Pei and Yongjin Wu : Key Laboratory of Geotechnical Mechanics and Engineering of the Ministry ofWater Resources, Yangtze River Scientific Research Institute,Wuhan, Hubei 430010, China

Abstract
In this paper, the seismic behavior of BRBF structures is studied and compared with special concentric braced frames (SCBF). To this purpose, three BRBF and three SCBF structures with 3, 5 and 10 stories are designed based on AISC360-5 and modelled using OpenSees. These structures are loaded in accordance with ASCE/SEI 7-10. Incremental nonlinear dynamic analysis (IDA) are performed on these structures for 28 different accelerograms and the median IDA curves are used to compare seismic capacity of these two systems. Results obtained, indicates that BRBF systems provide higher capacity for the target performance level in comparison with SCBF systems. And structures with high altitude (in this study, 5 and 10 stories) with the possibility of exceeding the collapse prevention performance level, further than lower altitude (here 3 floors) structures.

Key Words
incremental nonlinear dynamic analysis (IDA); buckling restrained braced frame (BRBF); special concentric braced frame (SCBF); seismic performance; level exceedance probability; analytical fragility curve

Address
M. Khorami : Facultad de Arquitectura y Urbanismo, Universidad Tecnológica Equinoccial, Calle Rumipamba s/n y Bourgeois, Quito, Ecuador /Facultad de Ingeniería Civil y Ambiental, Escuela Politécnica Nacional, Ladrón de Guevara E11-253L, Quito, Ecuador M. Khorami : Civil Engineering Department, Islamic Azad University, Tehran, Iran M. Alvansazyazdi : Facultad Ingeniería Ciencias Físicas y Matemática, Carrera Ingeniería Civil, Universidad Central del Ecuador, Quito, Ecuador 5Facultad de Arquitectura, Universidad Laica Eloy Alfaro de Manabí, Ecuador M. Shariati and A. Jalali : Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran Y. Zandi : Department of Civil Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran M.M. Tahir : UTM Construction Research Centre, Faculty of Civil Engineering, Institute for Smart Infrastructure and Innovative Construction, UTM, 81310, Johor Bahru, Johor, Malaysia

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