Vol.36/No.1 (139) (2021)

作者:

Vol.36/No.1 (139) (2021)

TitleStudy on a Post-earthquake Seismic Performance Evaluation Method for Low-rise RC buildings
AuthorChien-Kuo Chiu, Hsin-Fang Sung, Tsung-Chih Chiou
Keywordsresidual seismic capacity, damage level, reduction factor.
AbstractTo quantify the post-earthquake residual seismic capacity of reinforced concrete (RC) column members, the static-cyclic loading and dynamic loading experimental results obtained in previous work, and the “Pacific Earthquake Engineering Research Center Structural Performance Database (PEER)” are used to obtain reduction factors of strength, stiffness and energy dissipation. This work also applies the method of the modified nonlinear hinge and proposes the preliminary and detailed seismic performance assessment method for the residual seismic performance of earthquake-damaged RC buildings. In the case study, this work selects one actual earthquake-damaged building to display the post-earthquake assessment of seismic performance for a damaged RC building.
TitleConstruction cost analysis of school building seismic retrofit
AuthorYuan-Sen Yang,Yun-Ting Peng,Yu-Hsuan Huang, Tsung-Chih Chiou, Lap-Loi Chung, Shyh-Jiann Hwang
Keywordsschool building seismic retrofit, wing wall, RC jacketing, shear wall, construction cost
AbstractThe cases in the school building seismic retrofit have significant values for data analysis. The school building seismic retrofit data has been accumulated since 2009. More than 30,000 school building structures have been generally surveyed. More than 17,000 of them were preliminarily evaluated, and more than 10,000 of them which had significant risk of damage from earthquakes were evaluated. More than 6,000 of them have been retrofitted. As long as the analysis results are properly utilized, we will have more comprehensive understanding of construction cost, as well as potential for improving the administrative processes.
Based on the aforementioned database, this research analyzed the factors affecting the construction cost based on school locations, retrofit methods, and seismic capacity increment. In the statistics of the use of school building retrofit methods, it is found that wing walls, RC jacketing, and shear walls are the most commonly used retrofit methods. There are many factors that affect the project cost. This article studied the relationship between the retrofit cost and the above three factors through the data analysis.
TitleDesign of base-isolation systems subjected to pulse-like ground motions
AuthorNing-Kai Yang,Yin-Nan Huang,Hsun-Jen Liu, Shu-Hsien Chao
KeywordsNear-Fault Ground Motions; Base Isolation; Lead-Rubber Bearings; Non-Linear Response-History Analysis; GMPE
AbstractModernbuilding codes do not provide clearguidelineson the design of base-isolation systems against pulse-like ground motions, which may produce excessive displacement demand for isolators and endanger the systems. A procedureis proposed in this paper to address the impact of pulse-like ground motionson isolation systems. The procedure involves 1) the development of an “evaluation spectrum” using newly developed Taiwan ground motion prediction equations and a model for the ratio of spectral accelerations of pulse-like to non-pulse ground motions, and 2) selection and scaling of pulse-like records for nonlinear response-history analysis of the isolated building of interest. This paper presents an example of a 15-story steel special moment resisting frame isolated using lead-rubber bearings to demonstrate the proposed procedure.
TitleSeismic Isolation Retrofit and Foundation Replacement of Freeway Bridge
AuthorYin-Xuan Chen,Tien-Jen Hsiao,Ming-Shing Wu, Kang-Yu Peng, Guo-Long Chen
Keywordssystem of retrofit method, seismic isolator, foundation replacement method
AbstractTaiwan’s bridge seismic design specifications have evolved several version from 1987. In order to meet the seismic requirements under newest version specification. Freeway Bureau, MOTC has started existing bridge seismic capability evaluation and retrofitted after Chi-Chi Earthquake in 1999.
Because foundation retrofitting are expansive, we prefer to use “system retrofit method”. Conduct the feasibility studies on seismic isolation and damping devices. While the superstructure and pier are rigid connected, isolation bearing can’t install directly. An example of this is “Dong-Shan Bridge”. In this study, we explain the design considerations and methods of adding seismic isolation bearing to existing rigid piers. Furthermore, there are some cases where the spread foundation base will be scouring. An example of this is “Mei-Lin Bridge”. In order to increase earthquake and flood resistance at the same time. We use foundation replacement method to make spread foundation replace to pile foundation..
TitleSeismic Evaluation and Retrofit of the Isolated Bridge near Active Faults: Chianan Irrigation, Beigan No. 1 bridge
AuthorChih-Siou Gao, Tien-Jen Hsiao, Ming-Shing Wu,Kang-Yu Peng,Guo-Long Chen
KeywordsIsolated bridge, Near-fault effect, Seismic Evaluation and Retrofit, Fluid Viscous Damper
AbstractWith the development of the seismic isolation technology in Taiwan, Seismic isolation bearing has been used in some bridges to resist earthquakes. Since the construction of freeway NO.3 and the reconstruction of the bridge damaged by Chi-Chi earthquake,isolation technology has been used in three decade.MOTC also added a chapter “Seismic Isolation and Energy Dissipation Design” to “Specification for Seismic Design of Highways and Bridges” (2008).But the pulses in the near fault ground motion have a large ­ displacement response which is exceed the design displacementon isolated bridges due to their long period property.
Take “Chia-nan Irrigation Channel No.1 Bridge” for example. We studied the effects of earthquakes near and far fault region on seismic behavior of isolated bridge, and suggest the retrofit method. This research shows that resultant displacement of the existing seismic isolated bearings may exceed the design displacement under the far-fault earthquake due to the seismic force increased.Furthermore, the resultant displacement will be much larger under the near-fault earthquake when the period of the isolated bridge is closed to the pulse period.Finally, we install fluid viscous damper (FVD) to increase the overall bridge system damping and to reduce the displacement response of the seismic isolated bearing.
TitleRegression of Creep Prediction Formula of Concrete in Taiwan Basedon Database Analysisandits Applicationon Prestressed Concrete Bridge
AuthorWen-Cheng LIAO, Ho-Cheng HUANG, Jian-Jyun GAO , Ping-Hsun HUANG , Jumbo C.H. CHIANG
KeywordsDatabase, Long-term deformation, Creep,Prestressed concretebridge,Prestress loss
AbstractThis research integrates the test data of the past 40 years in Taiwan and establishes the “Shrinkage and Creep Database in Taiwan”. After comparing the domestic and foreign database, it is found that concrete in Taiwan has high cementitious material content, low water-cement ratio, and low aggregate stiffness, and it is not conservative if the foreign prediction model is directly applied. Therefore, Bažant’s Model B4 was selected as the basis of the prediction model, and the above parameters were localized and revised, and the prediction model of Taiwan ordinary concrete was proposed. In addition, this study extends the prediction model of ordinary concrete and revises the concrete with pozzolanic materials. Creep of concrete has a great influence on the long-term deformation of long-span prestressed bridges. In order to compare the difference between the domestic and foreign shrinkage and creep prediction models on the long-term deformation of the bridge, this study uses MIDAS Civil to establish a prestressed concrete bridge, and compares the analysis results between domestic and foreign prediction models. It is found that the foreign prediction models have seriously underestimated the deformation and prestress loss.