scholarly journals Seismic Performance Assessment of High Asphalt Concrete Core Rockfill Dam Considering Shorter Duration and Longer Duration

2021 ◽  
Author(s):  
benbo sun ◽  
Mingjiang Deng ◽  
Sherong Zhang ◽  
Chao Wang ◽  
Guojin Zhu
Keyword(s):  
Seismic Performance ◽  
Seismic Design ◽  
Asphalt Concrete ◽  
Fragility Curves ◽  
Performance Based Design ◽  
Design Approach ◽  
Seismic Performance Assessment ◽  
Concrete Core ◽  
Damage Indicators ◽  
Estimate Method

Abstract Current research trends in seismic frequent regions aim at developing the appropriate performance – based design approach for high asphalt concrete core rockfill dams (ACCRDs). Under intense ground motions (GMs), the seismic performance of dams depends on seismological characteristics mainly containing the frequency, amplitude, and duration. Recently, the characteristic of frequency and amplitude of GMs which can trigger severe damages to the dams has been accepted and incorporated into the seismic design codes in most countries. As one of the key characteristics of earthquakes, the duration of strong GMs also should be fully understood in order to carry out more reasonable performance – based design approach of dams. This paper explores the effect of the duration of strong GMs, investing the seismic performance of high ACCRDs by employing integrated duration concept, which can reflect the duration of all components of GMs. The high ACCRD was built in the commercial software ABAQUS considering the dam-reservoir-foundation interaction systems. Additionally, the coupling multiple stripe analysis and maximum likelihood estimate method are used to generate seismic fragility curves for the dam according to two damage indicators. Findings from this study revealed that the longer duration GMs can give rise to higher probability of exceedance (POE) of the dam than shorter duration. It is recommended that in the work of the current seismic design and seismic performance evaluate, the effects of GM duration in addition to frequency and amplitude should be considered.

scholarly journals 2015 Nepal earthquake: seismic performance and post-earthquake reconstruction of stone in mud mortar masonry buildings

2020 ◽  
Vol 18 (8) ◽  
pp. 3863-3896 ◽  
Author(s):  
Rohit Kumar Adhikari ◽  
Dina D’Ayala
Keyword(s):  
Seismic Performance ◽  
Seismic Design ◽  
Failure Modes ◽  
Construction Materials ◽  
Seismic Capacity ◽  
Seismic Performance Assessment ◽  
Capacity Curves ◽  
2015 Gorkha Earthquake ◽  
Seismic Design Code ◽  
Earthquake Reconstruction

Abstract The residential building typology of Stone in Mud Mortar (SMM) masonry contributed significantly to the seismic losses caused by the 2015 Nepalese seismic sequence, also known as the 2015 Gorkha earthquake. SMM masonry is the most common construction type in Nepal, and notwithstanding the extensive damage, this has persisted in the post-earthquake reconstruction. This paper provides first an overview of the extent of damage and typical failure modes suffered by this typology. Some pressing issues in the ongoing post-earthquake reconstruction, such as building usability, construction quality are then discussed. The results of seismic analyses on both the pre-earthquake (PRE-SMM) and post-earthquake built (POST-SMM) typologies, using the applied element method employing a modelling strategy that accounts for the random shape of stone units, are then presented and discussed in terms of capacity curves and failure mechanisms. As per the seismic design code of Nepal, seismic performance assessment is conducted to understand the seismic design levels of these constructions. Finally, seismic fragility and vulnerability functions for both the PRE-SMM and POST-SMM typologies, considering the uncertainty in ground motions and material quality, are presented and discussed. Considering the seismic hazard in Nepal, the PRE-SMM typology is found to be highly vulnerable and seismic strengthening of these buildings is urgent. On the other hand, the POST-SMM typology has adequate seismic capacity and performs within the serviceability limit, given the quality of both the construction materials and workmanship are not compromised.

Risk-Based Seismic Performance Assessment of Pressurized Piping Systems Considering Ratcheting

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
A. Ravi Kiran ◽  
G. R. Reddy ◽  
M. K. Agrawal
Keyword(s):  
Performance Assessment ◽  
Seismic Performance ◽  
Fragility Curves ◽  
Limit State ◽  
Frequency Variation ◽  
Seismic Load ◽  
Piping System ◽  
Seismic Performance Assessment ◽  
Limit States ◽  
Piping Systems

Abstract A procedure is described for risk-based seismic performance assessment of pressurized piping systems considering ratcheting. The procedure is demonstrated on a carbon steel piping system considered for OECD-NEA benchmark exercise on quantification of seismic margins. Initially, fragility analysis of the piping system is carried out by considering variability in damping and frequency. Variation in damping is obtained from the statistical analysis of the damping values observed in earlier experiments on piping systems and components. The variation in ground motion is considered by using 20 strong motion records of the intraplate region. Floor motion of a typical reactor building of a nuclear power plant under these actual earthquake records is evaluated and applied to the piping system. The performance evaluation of the piping system in terms of ratcheting is carried out using a numerical approach, which was earlier validated with shake table ratcheting tests on piping components and systems. Three limit states representing performance levels of the piping system under seismic load are considered for fragility evaluation. For each limit state, probability of exceedance at different levels of floor motion is evaluated to generate a fragility curve. Subsequently, the fragility curves of the piping systems are convoluted with hazardous curves for a typical site to obtain the risk in terms of annual probability of occurrence of the performance limits.

scholarly journals Experimental Study on the Behavior of Existing Reinforced Concrete Multi-Column Piers under Earthquake Loading

2021 ◽  
Vol 11 (6) ◽  
pp. 2652
Author(s):  
Jung Han Kim ◽  
Ick-Hyun Kim ◽  
Jin Ho Lee
Keyword(s):  
Seismic Performance ◽  
Seismic Design ◽  
Bridge Piers ◽  
Scale Model ◽  
Inertia Force ◽  
Small Scale ◽  
Lap Splice ◽  
Existing Structures ◽  
Seismic Design Code ◽  
Seismic Force

When a seismic force acts on bridges, the pier can be damaged by the horizontal inertia force of the superstructure. To prevent this failure, criteria for seismic reinforcement details have been developed in many design codes. However, in moderate seismicity regions, many existing bridges were constructed without considering seismic detail because the detailed seismic design code was only applied recently. These existing structures should be retrofitted by evaluating their seismic performance. Even if the seismic design criteria are not applied, it cannot be concluded that the structure does not have adequate seismic performance. In particular, the performance of a lap-spliced reinforcement bar at a construction joint applied by past practices cannot be easily evaluated analytically. Therefore, experimental tests on the bridge piers considering a non-seismic detail of existing structures need to be performed to evaluate the seismic performance. For this reason, six small scale specimens according to existing bridge piers were constructed and seismic performances were evaluated experimentally. The three types of reinforcement detail were adjusted, including a lap-splice for construction joints. Quasi-static loading tests were performed for three types of scale model with two-column piers in both the longitudinal and transverse directions. From the test results, the effect on the failure mechanism of the lap-splice and transverse reinforcement ratio were investigated. The difference in failure characteristics according to the loading direction was investigated by the location of plastic hinges. Finally, the seismic capacity related to the displacement ductility factor and the absorbed energy by hysteresis behavior for each test were obtained and discussed.

Seismic performance assessment of multi-story steel frames with curved dampers and semi-rigid connections

2021 ◽  
Vol 182 ◽  
pp. 106666
Author(s):  
S.F. Fathizadeh ◽  
S. Dehghani ◽  
T.Y. Yang ◽  
A.R. Vosoughi ◽  
E. Noroozinejad Farsangi ◽  
...  
Keyword(s):  
Performance Assessment ◽  
Seismic Performance ◽  
Steel Frames ◽  
Seismic Performance Assessment
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