scholarly journals Seismic Fragility Analysis of 3D Vertical Irregular Reinforced Concrete Structures

2021 ◽  
Author(s):  
Amr Ghanem ◽  
Do-Soo Moon
Keyword(s):  
Reinforced Concrete ◽  
Mass Distribution ◽  
Structural Reliability ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Three Dimensional ◽  
Analytical Models ◽  
Seismic Fragility ◽  
Reliability Method ◽  
Dimensional Models

Because changes in the structure's occupancy significantly affect the mass distribution and the structure's behavior, changing mass distribution might make the building more irregular and vulnerable to seismic ground motions. Many researchers tried to evaluate their seismic vulnerability. Most previous studies used simplified structural representations such as two-dimensional models that could not represent accurate seismic behavior from the coupling between lateral and torsional responses. For space structures with high irregularity, more realistic representations such as three-dimensional models are needed for the proper seismic assessment. To handle the computational challenge in deriving fragility curves, this research utilized a new structural reliability method that incorporates structural analysis and reliability analysis to efficiently and accurately calculate the failure probability with the first-order reliability method (FORM). This study investigates the seismic vulnerability of space-reinforced concrete frame structures with varying vertical irregularities. More representative seismic fragility curves are derived with their three-dimensional analytical models. The significant effect of the structure's vertical irregularity on seismic vulnerability is highlighted.

scholarly journals Seismic Vulnerability Assessment of Skewed Reinforced Concrete Bridges

2021 ◽  
Author(s):  
Amr Ghanem ◽  
Do-Soo Moon ◽  
Young Joo Lee
Keyword(s):  
Reinforced Concrete ◽  
Structural Reliability ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Transportation Systems ◽  
Earthquake Ground Motion ◽  
Skew Angle ◽  
Skewed Bridges ◽  
Reliability Method ◽  
Bridge Models

Skewed bridges are commonly used in highway interchanges where the straight (unskewed) bridges are not suitable. There have been several observations of heavy damage of bridges that have geometric irregularities, especially significant skewness. Such damage severely disrupts transportation systems, leading to substantial economic consequences. Skewed bridges are often inevitable due to the complexity and lack of orthogonality of transportation networks; hence better quantification of the effects of skewness on the bridge performance is a more viable approach than avoiding skewed bridges. This research focuses on the seismic vulnerability analysis of skewed reinforced concrete (RC) bridges. From the straight to highly skewed, various bridge models are created based on design example No. 4 prepared by the US Federal Highway Administration (FHWA). A set of earthquake ground motion records is carefully selected to impose consistent seismic demands on bridges. The fragility relationships for all bridge configurations are derived from the non-linear dynamic response history analysis. A new structural reliability method is utilized to handle the computational challenge in deriving fragility curves, which incorporates the structural analysis and reliability analysis to calculate the failure probability efficiently and accurately with the first-order reliability method (FORM). An attempt is made to parameterize the problem based on the skew angle. It is shown that the skew angle has a direct effect on the seismic vulnerability of RC bridges. The results reported will be helpful for new designs of skew RC bridges.

scholarly journals Time-Dependent Reliability Analysis of Reinforced Concrete Beams Subjected to Uniform and Pitting Corrosion and Brittle Fracture

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1820
Author(s):  
Mohamed El Amine Ben Seghier ◽  
Behrooz Keshtegar ◽  
Hussam Mahmoud
Keyword(s):  
Reinforced Concrete ◽  
Brittle Fracture ◽  
Reliability Analysis ◽  
Pitting Corrosion ◽  
Structural Reliability ◽  
Time Dependent ◽  
State Function ◽  
Rc Beams ◽  
Highly Nonlinear ◽  
Reliability Method

Reinforced concrete (RC) beams are basic elements used in the construction of various structures and infrastructural systems. When exposed to harsh environmental conditions, the integrity of RC beams could be compromised as a result of various deterioration mechanisms. One of the most common deterioration mechanisms is the formation of different types of corrosion in the steel reinforcements of the beams, which could impact the overall reliability of the beam. Existing classical reliability analysis methods have shown unstable results when used for the assessment of highly nonlinear problems, such as corroded RC beams. To that end, the main purpose of this paper is to explore the use of a structural reliability method for the multi-state assessment of corroded RC beams. To do so, an improved reliability method, namely the three-term conjugate map (TCM) based on the first order reliability method (FORM), is used. The application of the TCM method to identify the multi-state failure of RC beams is validated against various well-known structural reliability-based FORM formulations. The limit state function (LSF) for corroded RC beams is formulated in accordance with two corrosion types, namely uniform and pitting corrosion, and with consideration of brittle fracture due to the pit-to-crack transition probability. The time-dependent reliability analyses conducted in this study are also used to assess the influence of various parameters on the resulting failure probability of the corroded beams. The results show that the nominal bar diameter, corrosion initiation rate, and the external loads have an important influence on the safety of these structures. In addition, the proposed method is shown to outperform other reliability-based FORM formulations in predicting the level of reliability in RC beams.

Seismic Fragility Analysis of Hill Buildings with Uneven Ground Column Heights

2014 ◽  
Vol 638-640 ◽  
pp. 1848-1853
Author(s):  
Lin Qing Huang ◽  
Li Ping Wang ◽  
Chao Lie Ning
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Slope Angle ◽  
Seismic Fragility ◽  
Exceedance Probability ◽  
Considerable Influence ◽  
Analysis Method ◽  
Ground Acceleration ◽  
Mountainous Regions ◽  
The Hill

The hill buildings sited on slopes have been widely constructed in mountainous regions. In order to estimate the seismic vulnerability of the hill buildings with uneven ground column heights under the effect of potential earthquakes, the exceedance probabilities of the hill buildings sited on different angle slopes in peak ground acceleration (PGA) are calculated and compared by using the incremental dynamic analysis method. The fragility curves show the slope angle has considerable influence on the seismic performance. Specifically, the exceedance probability increases with the increasing of the slope angle at the same performance level.

scholarly journals Fragility Assessment of a Container Crane under Seismic Excitation Considering Uplift and Derailment Behavior

2019 ◽  
Vol 9 (21) ◽  
pp. 4660
Author(s):  
Quang Huy Tran ◽  
Jungwon Huh ◽  
Nhu Son Doan ◽  
Van Ha Mac ◽  
Jin-Hee Ahn
Keyword(s):  
Structural Damage ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Three Dimensional ◽  
Time History ◽  
Element Model ◽  
Seismic Excitation ◽  
Damage State ◽  
Limit States ◽  
Container Crane

While the container crane is an important part of daily port operations, it has received little attention in comparison with other infrastructures such as buildings and bridges. Crane collapses owing to earthquakes affect the operation of the port and indirectly impact the economy. This study proposes fragility analyses for various damage levels of a container crane, thus enabling the port owner and partners to better understand the seismic vulnerability presented by container cranes. A large number of nonlinear time-history analyses were applied for a three-dimensional (3D) finite element model to quantify the vulnerability of a Korean case-study container crane considering the uplift and derailment behavior. The uncertainty of the demand and capacity of the crane structures were also considered through random variables, i.e., the elastic modulus of members, ground motion profile, and intensity. The results analyzed in the case of the Korean container crane indicated the probability of exceeding the first uplift with or without derailment before the crane reached the structure’s limit states. This implies that under low seismic excitation, the crane may be derailed without any structural damage. However, when the crane reaches the minor damage state, this condition is always coupled with a certain probability of uplift with or without derailment. Furthermore, this study proposes fragility curves developed for different structural periods to enable port stakeholders to assess the risk of their container crane.

scholarly journals SEISMIC FRAGILITY ASSESSMENT AND RETROFIT OF A GOVERNMENT HOSPITAL BUILDING IN CHITTAGONG, BANGLADESH

2018 ◽  
Vol 30 (1) ◽  
Author(s):  
Md. AbulHasan ◽  
Md. Abdur Rahman Bhuiyan
Keyword(s):  
Ground Motion ◽  
Return Period ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Response Spectrum ◽  
Seismic Fragility ◽  
Earthquake Ground Motion ◽  
Type I ◽  
Type Ii ◽  
Ground Motion Records

Chittagong Medical College Hospital (CMCH) is one of the most important government hospitals in Bangladesh. It is located in the heart of Chittagong city, the only port city of Bangladesh. Bangladesh National Building Code (BNBC) is the only official document, which has been used since 1993 as guidelines for seismic design of buildings. As per the guidelines of BNBC, the CMCH building was designed for an earthquake ground motion having a return period of 200 years. However, the revised version of BNBC has suggested that the building structures shall be designed for an earthquake ground motion having a return period of 2475 years. It is mentioned that a single seismic performance objective, the life safety, of the building is considered in both versions of BNBC. Considering the significant importance of CMCH building in providing the emergency facilities during and after the earthquake, it is indispensable to evaluate its seismic vulnerability for the two types of earthquake ground motion records having return period of 200 (Type-I) and 2475 (Type-II) years. In this regard, this paper deals with the seismic vulnerability assessment of the existing ancillary building (AB) of CMCH. The seismic vulnerability of building is usually expressed in the form of fragility curves, which display the conditional probability that the structural demand (structural response) caused by various levels of ground shaking exceeds the structural capacity defined by a damage state. The analytical method based on elastic response spectrum analyses results is used in evaluating the seismic fragility curves of the building. To the end, 3-D finite element model of the building subjected to 18 ground motion records having PGA of 0.325g to 0.785g has been used in theresponse spectrum analysis in order to evaluate its inter-story-drift ratio (IDR), an engineeringdemand parameter (EDP) for developing fragility curves. The analytical results have shown thatstructural deficiencies exist in the existing ancillary building (AB) for the Type-II earthquakeground motion record, which requires the building to be retrofitted to ensure that the existingancillary building (AB) becomes functional during and after the Type-II earthquake groundmotion record.

scholarly journals Fragility Assessment of Container Crane under Seismic Excitation Considering Uplift and Derailment Behavior

2019 ◽  
Author(s):  
Quang Huy Tran ◽  
Jungwon Huh ◽  
Nhu Son Doan ◽  
Van Ha Mac ◽  
Jin-Hee Ahn
Keyword(s):  
Structural Damage ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Three Dimensional ◽  
Time History ◽  
Element Model ◽  
Seismic Excitation ◽  
Damage State ◽  
Limit States ◽  
Container Crane

While the container crane is an important part of daily port operations, it has received little attention compared with other infrastructures, such as buildings and bridges. Crane collapse due to earthquake affects the operation of the port, and indirectly impacts the economy. This study proposes fragility analyses for various damage levels of the container crane that allow the port owner and partners to better understand the seismic vulnerability presented by container cranes. A large quantity of nonlinear time history analyses was applied for a three-dimensional (3D) finite element model to quantify the vulnerability of the container crane in considering the uplift and derailment behavior. The uncertainty of demand and capacity of the crane structures were also considered through random variables, i.e. elastic modulus of members, ground motion profile, and intensity. The results analyzed in the case of a Korean container crane showed that the probability of exceeding the first uplift with or without derailment is shown before the crane reaches the structure’s limit states. This means that under low seismic excitation, the crane might be derailed without any structural damage. But when the crane reaches the minor damage state, it is always coupled with a certain probability of uplift with or without derailment. This study also proposes the fragility curves developed for different structural periods to enable port stakeholders to assess the risk of their container crane.

scholarly journals Seismic fragility curves based on the probability density evolution method

2017 ◽  
Vol 39 (2) ◽  
pp. 177-189
Author(s):  
Thuat-Cong Dang ◽  
Thien-Phu Le ◽  
Pascal Ray
Keyword(s):  
Probability Density ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Fragility Curve ◽  
Seismic Fragility ◽  
Cumulative Probability ◽  
Density Evolution ◽  
Probability Density Evolution Method ◽  
Log Normal ◽  
Probability Density Evolution

A seismic fragility curve that shows the probability of failure of a structure in function of a seismic intensity, for example peak ground acceleration (PGA), is a powerful tool for the evaluation of the seismic vulnerability of the structures in nuclear engineering and civil engineering. The common assumption of existing approaches is that the fragility curve is a cumulative probability log-normal function. In this paper, we propose a new technique for construction of seismic fragility curves by numerical simulation using the Probability Density Evolution Method (PDEM). From the joint probability density function between structural response and random variables of a system and/or excitations, seismic fragility curves can be derived without the log-normal assumption. The validation of the proposed technique is performed on two numerical examples.

Seismic fragility assessment of multi-span concrete highway bridges in British Columbia considering soil–structure interaction

2021 ◽  
Vol 48 (1) ◽  
pp. 39-51 ◽  
Author(s):  
A.H.M. Muntasir Billah ◽  
M. Shahria Alam
Keyword(s):  
British Columbia ◽  
Soil Structure ◽  
Seismic Vulnerability ◽  
Structural Characteristics ◽  
Fragility Curves ◽  
Highway Bridges ◽  
System Level ◽  
Soil Structure Interaction ◽  
Seismic Fragility ◽  
Structure Interaction

Fragility curve is an effective tool for identifying the potential seismic risk and consequences during and after an earthquake. Recent seismic events have shown that bridges are highly sensitive and vulnerable during earthquakes. There has been limited research to evaluate the seismic vulnerability of the existing bridges in British Columbia (BC), which could help in the decision-making process for seismic upgrade. This study focuses on developing seismic fragility curves for typical multi-span continuous concrete girder bridges in BC. Ground motions compatible with the seismic hazard were used as input excitations for vulnerability assessment. Uncertainties in material and geometric properties were considered to represent the bridges with similar structural characteristics and construction period. The fragility of the bridge is largely attributable to the fragilities of the columns, and to a lesser extent, the abutment and bearing components. The results of this study show that, although not very significant, the soil–structure interaction has some effect on the component fragility where this effect is not very significant at the bridge system level.

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