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Abstract
This paper presents seismic performance and reliability evaluation on steel-timber hybrid shear wall systems composed of steel moment resisting frames and infill light frame wood shear walls. Based on experimental observations, damage assessment was conducted to determine the appropriate damage-related performance objectives for the hybrid shear wall systems. Incremental time-history dynamic analyses were conducted to establish a database of seismic responses for the hybrid systems with various structural configurations. The associated reliability indices and failure probabilities were calculated by two reliability methods (i.e., fragility analysis and response surface method). Both methods yielded similar estimations of failure probabilities. This study indicated the greatly improved seismic performance of the steel-timber hybrid shear wall systems with stronger infill wood shear walls. From a probabilistic perspective, the presented results give some insights on quantifying the seismic performance of the hybrid system under different seismic hazard levels. The reliability-based approaches also serve as efficient tools to assess the performance-based seismic design methodology and calibration of relative code provisions for the proposed steel-timber hybrid shear wall systems.

Key Words
steel-timber hybrid structures; seismic reliability; shear walls; fragility analysis; response surface method

Address
Zheng Li, Minjuan He and Ruirui Zhou: Department of Structural Engineering, Tongji University, Shanghai, 200092, China Frank Lam: Department of Wood Science, University of British Columbia, Vancouver, Canada Minghao Li: Department of Civil & Natural Resources Engineering, University of Canterbury, Christchurch, New Zealand

Abstract
High Damping Rubber bearings (HDR bearings) have been used in the seismic design of bridge structures widely in China. In earthquakes, structural natural periods will be extended, seismic energy will be dissipated by this kind of bearing. Previously, cyclic loading method was used mainly for test studies on mechanical properties of HDR bearings, which cannot simulate real seismic responses. In this paper, Real-Time Substructure (RTS) test study on mechanical properties of HDR bearings was conducted and it was found that the loading rate effect was not negligible. Then the influence of peak acceleration of ground motion was studied. At last test results were compared with a numerical simulation in the OpenSees software framework with the Kikuchi model. It is found that the Kikuchi model can simulate real mechanical properties of HDR bearings in earthquakes accurately.

Key Words
high damping rubber bearing; real-time substructure test; loading rate; numerical simulation

Address
Tianbo Peng and Yicheng Wu: 1) State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai, China 2) College of Civil Engineering, Tongji University, Shanghai, China

Abstract
In this paper, a simplified evaluation method of the skeleton curve for reinforced concrete (RC) frame with unreinforced masonry (URM) infill is proposed in a practical form, based on the previous studies. The backbone curve for RC boundary frame was modeled by a tri-linear envelope with cracking and yielding points. On the other hand, that of URM infill was modeled by representative characteristic points of cracking, maximum, and residual strength; also, the interaction effect between RC boundary frame and the infill was taken into account. The overall force-displacement envelopes by the sum of RC boundary frame and URM infill, where the backbone curves of the infill from other studies were also considered, were then compared with the previous experimental results. The simplified estimation results from this study were found to almost approximate the overall experimental results with conservative evaluations, and they showed much better agreement than the cases employing the infill envelopes from other studies.

Key Words
RC frame; URM infill; diagonal strut mechanism; backbone curve; ASCE41-06

Address
Kiwoong Jin: Department of Architectural and Building Science, Tohoku University, Sendai, Japan Ho Choi: Institution of Industrial Science, The University of Tokyo, Tokyo, Japan

Abstract
A simplified framework for the probabilistic estimation of economic losses induced by the structural vulnerability in single-story and single-bay precast industrial buildings is presented. The simplifications introduced in the framework are oriented to the definition of an expeditious procedure adoptable by government agencies and insurance companies for preliminary risk assessment. The economic losses are evaluated considering seismic hazard, structural response, damage resulting from the structural vulnerability and only structural-vulnerability-induced e]conomic losses, i.e., structural repair or reconstruction costs (stock and flow costs) and content losses induced by structural collapse. The uncertainties associated with each step are accounted for via Monte Carlo simulations. The estimation results in a probabilistic description of the seismic risk of portal-like industrial buildings, expressed in terms of economic losses for each occurrence (i.e., seismic event) that owners (i.e., insured) and stakeholders can use to make risk management decisions. The outcome may also be useful for the definition of the insurance premiums and the evaluation of the risks and costs for the owner corresponding to the insurance industrial costs. A prototype of a precast concrete industrial building located in Mirandola, Italy, hit by the 2012 Emilia earthquake, is used as an example of the application of the procedure.

Key Words
structural vulnerability; insurance policy; uncertainties; monte carlo

Address
Cristoforo Demartino and Giorgio Monti: 1) College of Civil Engineering, Nanjing Tech University, Nanjing 211816, PR China 2) DISG, Sapienza University of Rome, via A. Gramsci 53, 00197 Rome, Italy Ivo Vanzi: Department of Engineering and Geology, University \"G. d\' Annunzio\" of Chieti-Pescara, viale Pindaro, Pescara, Italy

Abstract
The first determination and assessment of the damages to structures after the earthquake is important for preventing increase in loss of life and property that may occur in later times. When rapid damage assessment is performed after an earthquake, damage assessment forms are generally used. The forms that are filled in the field are assessed in the office environment later. In this study, while the process of earthquake damage assessment was being carried out, the ready-made form was moved to web base and the data to be obtained in the field was transferred to the database by means of tablets and smart phones. Keeping earthquake damages in a database will contribute to the studies to be conducted on earthquake and the earthquake regulations to be prepared. Furthermore, emergency damage assessment will be performed faster and more reliably after the earthquake through this study. As the data transferred to the web base is accessible to different people, savings will be provided for both time and personnel. Furthermore, the assessment will have a healthier and scientific basis. In this study, exemplification was conducted for six different reinforced concrete buildings that were damaged during Van earthquake in October 23. With this study, damage assessment procedures can be completed as soon as possible.

Key Words
earthquake; damage assessment; reinforced-concrete; web based; database

Address
Ercan Isik:Department of Civil Engineering, Faculty of Engineering and Architecture, Bitlis Eren University, TR13100, Turkey Mehmet F. Isik :Department of Electric-Electronics Engineering, Faculty of Engineering, Hitit University, TR19030, Turkey Mehmet A. Buibui:Department of Computer, Vocational School of Technical Sciences, Hitit University, TR19030, Turkey

Abstract
With the growing demand for metallic dampers in engineering practice, it is urgent to establish a reasonable approach to evaluating the mechanical performance of metallic dampers under seismic excitations. This paper introduces an effective method for parameter identification of the modified Bouc-Wen model and its application to evaluating the fatigue performance of metallic dampers (MDs). The modified Bouc-Wen model which eliminates the redundant parameter is used to describe the hysteresis behavior of MDs. Relations between the parameters of the modified Bouc-Wen model and the mechanical performance parameters of MDs are studied first. A modified Genetic Algorithm using real-integer hybrid coding with relative fitness as well as adaptive crossover and mutation rates (called RFAGA) is then proposed to identify the parameters of the modified Bouc-Wen model. A reliable approach to evaluating the fatigue performance of the MDs with respect to the Chinese Code for Seismic Design of Buildings (GB 50011-2010) is finally proposed based on the research results. Experimental data are employed to demonstrate the process and verify the effectiveness of the proposed approach. It is shown that the RFAGA is able to converge quickly in the identification process, and the simulation curves based on the identification results fit well with the experimental hysteresis curves. Furthermore, the proposed approach is shown to be a useful tool for evaluating the fatigue performance of MDs with respect to the Chinese Code for Seismic Design of Buildings (GB 50011-2010).

Key Words
parameter identification; metallic dampers; Bouc-Wen model; genetic algorithm

Address
Ganping Shu and Zongjing Li:School of Civil Engineering, Southeast University, Nanjing 210096, China

Abstract
In the present study a capacity spectrum method based on constant ductility inelastic spectra to estimate the seismic performance of structures equipped with elastic viscous dampers is presented. As the definition of the structures' effective damping, due to the damping system, is necessary, an alternative method to specify the effective damping ratio ξeff is presented. Moreover, damping reduction factors (B) are introduced to generate high damping elastic demand spectra. Given the elastic spectra for damping ratio ξeff, the performance point of the structure can be obtained by relationships that relate the strength demand reduction factor (R) with the ductility demand factor (μ). As such expressions that link the above quantities, known as R – μ – T relationships, for different damping levels are presented. Moreover, corrective factors (Bv) for the pseudo-velocity spectra calculation are reported for different levels of damping and ductility in order to calculate with accuracy the values of the viscous dampers velocities. Finally, to evaluate the results of the proposed method, the whole process is applied to a four-storey reinforced concrete frame structure and to a six-storey steel structure, both equipped with elastic viscous dampers.

Key Words
simplified analysis method; capacity spectrum method; passive energy dissipation systems; high damping spectra; inelastic spectra; linear viscous damping

Address
Kosmas E. Bantilas, Ioannis E. Kavvadias and Lazaros K. Vasiliadis:Department of Civil Engineering, Democritus University of Thrace, Campus of Kimmeria, 67100, Xanthi, Greece

Abstract
The present study considers a multi-span continuous bridge, isolated by lead rubber bearing (LRB). Dynamic soil-structure interaction (SSI) is modelled with the help of a simplified, sway-rocking model for different types of soil. It is well understood from the literature that SSI influences the structural responses and the isolator performance. However, the above-mentioned effect of SSI also depends on the earthquake ground motion properties. It is very important to understand how the interaction between soil and structure varies with the earthquake ground motion characteristics but, as far as the knowledge of the authors go, no study has been carried out to investigate this effect. Therefore, the objectives of the present study are to investigate the influence of earthquake ground motion characteristics on: (a) the responses of a multi span bridge (isolated and non-isolated), (b) the performance of the isolator and, most importantly, (c) the soil-structure interaction. Statistical analyses are conducted by considering 14 earthquakes which are selected in such a way that they can be categorized into three frequency content groups according to their peak ground acceleration to peak ground velocity (PGA/PGV) ratio. Lumped mass model of the bridge is developed and time history analyses are carried out by solving the governing equations of motion in the state space form. The performance of the isolator is studied by comparing the responses of the bridge with those of the corresponding uncontrolled bridge (i.e., non-isolated bridge). On studying the effect of earthquake motions, it is observed that the earthquake ground motion characteristics affect the interaction between soil and structure in such a way that the responses decrease with increase in frequency content of the earthquake for all the types of soil considered. The reverse phenomenon is observed in case of the isolator performance where the control efficiencies increase with frequency content of earthquake.

Key Words
bridge; elastomeric bearings; dynamic soil structure interaction; earthquake; frequency content

Address
B Neethu, Diptesh Das and Siddharth Garia:Department of Civil Engineering, National Institute of Technology Durgapur, West Bengal, India

Abstract
Dry bridges have been widely applied in the Qinghai-Tibet Railway (QTR) to minimize the thermal disturbance of engineering to the permafrost. However, because the Qinghai-Tibet Plateau is an area with a high potential occurrence of earthquakes, seismic action can easily destroy the dry bridges. Therefore, a three-dimensional numerical model, with consideration of the soil-pile interactions, is established to investigate the thermal characteristics and their impact on the seismic response of the dry bridge in permafrost region along the QTR. The numerical results indicate that there exist significant differences in the lateral displacement, shear force, and bending moment of the piles in different thermal conditions under seismic action. When the active layer become from unfrozen to frozen state, the maximum displacement of the bridge pile reduces, and the locations of the zero and peak values of the shear force and bending moment also change. It is found that although the higher stiffness of frozen soil confines the lateral displacement of the pile, compared with unfrozen soil, it has an adverse effect on the earthquake energy dissipation capacity.

Key Words
numerical analysis; dry bridge; thermal characteristics; soil-pile interaction; seismic response; permafrost region

Address
Xiyin Zhang: State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China Mingyi Zhang: State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China Xingchong Chen: School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China Shuangyang Li and Fujun Niu: State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences, Lanzhou 730000, China

Abstract
Seismic safety evaluation of weir structure is significant considering the catastrophic economical consequence of operational disruption. In recent years, the seismic probabilistic risk assessment (SPRA) has been issued as a key area of research for the hydraulic system to mitigate and manage the risk. The aim of this paper is to assess the seismic probabilistic risk of weir structures employing the seismic hazard and the structural fragility in Korea. At the first stage, probabilistic seismic hazard analysis (PSHA) approach is performed to extract the hazard curve at the weir site using the seismic and geological data. Thereafter, the seismic fragility that defines the probability of structural collapse is evaluated by using the incremental dynamic analysis (IDA) method in accordance with the four different design limit states as failure identification criteria. Consequently, by combining the seismic hazard and fragility results, the seismic risk curves are developed that contain helpful information for risk management of hydraulic structures. The tensile stress of the mass concrete is found to be more vulnerable than other design criteria. The hazard deaggregation illustrates that moderate size and far source earthquakes are the most likely scenario for the site. In addition, the annual loss curves for two different hazard source models corresponding to design limit states are extracted.

Key Words
seismic risk assessment; weir structure; seismic fragility; seismic hazard analysis; annual loss

Address
Jahangir Alam, Dookie Kim:Civil and Environmental Engineering, Kunsan National University, 558 Daehak-ro, Gunsan-si 54150, Republic of Korea Byounghan Choi:Rural Research Institute, 870, Haean-ro Sangnok-gu, Ansan-si Gyeonggi-do, 15634, Republic of Korea

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