Seismic collapse probability of eccentrically braced steel frames

2017 ◽  
Vol 24 (1) ◽  
pp. 37-52
Author(s):  
Yongsheng Qi ◽  
Weiqing Li ◽  
Ningning Feng
Keyword(s):  
Steel Frames ◽  
Collapse Probability ◽  
Seismic Collapse

Comparison of steel frames with RWS and WFP beam-to-column connections through seismic fragility analysis

2020 ◽  
pp. 136943322097728
Author(s):  
Haoran Yu ◽  
Weibin Li
Keyword(s):  
Limit State ◽  
Pushover Analysis ◽  
Steel Frames ◽  
Fragility Analysis ◽  
Structural Safety ◽  
Seismic Fragility ◽  
Fe Modelling ◽  
Collapse Resistance ◽  
Seismic Collapse ◽  
Probabilistic Seismic Demand

Reduced web section (RWS) connections and welded flange plate (WFP) connections can both effectively improve the seismic performance of a structure by moving plastic hinges to a predetermined location away from the column face. In this paper, two kinds of steel frames—with RWS connections and WFP connections—as well as different frames with welded unreinforced flange connections were studied through seismic fragility analysis. The numerical simulation was conducted by using multiscale FE modelling. Based on the incremental dynamic analysis and pushover analysis methods, probabilistic seismic demand analysis and seismic capability analysis were carried out, respectively. Finally, combined with the above analysis results, probabilistic seismic fragility analysis was conducted on the frame models. The results showed that the RWS connection and WFP connection (without double plates) have little influence on reducing the maximum inter-storey drift ratio under earthquake action. RWS connections slightly reduce the seismic capability in non-collapse stages and improve the seismic collapse resistance of a structure, which exhibits good structural ductility. WFP connections can comprehensively improve the seismic capability of a structure, but the seismic collapse resistance is worse than that of RWS connections when the structure has a large number of storeys. The frame with WFP connections has a lower failure probability at every seismic limit state, while the frame with RWS connections sacrifices some of its structural safety in non-collapse stages to reduce the collapse probability.

Seismic Collapse Probability Considering Pounding and Financial Loss Estimation of Base-Isolated Reinforced Concrete Buildings

2018 ◽  
Vol 12 (03) ◽  
pp. 1850008 ◽  
Author(s):  
Satish Bhagat ◽  
Anil C. Wijeyewickrema
Keyword(s):  
Reinforced Concrete ◽  
Three Dimensional ◽  
Loss Estimation ◽  
Financial Loss ◽  
Reinforced Concrete Buildings ◽  
Nonstructural Components ◽  
Concrete Buildings ◽  
Collapse Probability ◽  
Seismic Collapse ◽  
Financial Losses

In this paper, the seismic collapse probability of base-isolated reinforced concrete buildings considering pounding with a moat wall and financial loss estimation is studied. For this purpose, three-dimensional finite element models of a code-compliant 10-story base-isolated shear wall-frame (BI-SWF) building and a 10-story base-isolated moment resisting frame (BI-MRF) building are used. Results indicate that the BI-MRF building has a greater probability of collapse compared to that of the BI-SWF building, the probability of collapse in 50 years for the BI-MRF building is 1.3 times greater than that of the BI-SWF building for both no pounding and pounding cases. The probability of collapse increases when pounding is considered, which results in a smaller value of the collapse margin ratio compared to no pounding case for both the buildings. The financial losses resulting from damage to the BI-MRF and BI-SWF buildings under design earthquake (DE) and risk-targeted maximum considered earthquake (MCER) levels are calculated for the no pounding case, since there was no pounding under DE-level and very few instances of pounding under MCER-level. Calculation of financial losses due to damage to structural and nonstructural components, service equipment and downtime shows that the BI-SWF building results in larger repair costs and downtime cost compared to the BI-MRF building.

Assessment of seismic collapse probability of RC shaft supported tank

Structures ◽  
2021 ◽  
Vol 33 ◽  
pp. 2639-2658
Author(s):  
Jignesh Amin ◽  
Kaushik Gondaliya ◽  
Chirag Mulchandani
Keyword(s):  
Collapse Probability ◽  
Seismic Collapse

scholarly journals Seismic collapse safety of reinforced concrete moment resisting frames with/without beam-column joint detailing

2021 ◽  
Vol 54 (1) ◽  
pp. 1-20
Author(s):  
Naveed Ahmad ◽  
Muhammad Rizwan ◽  
Muhammad Ashraf ◽  
Akhtar Naeem Khan ◽  
Qaisar Ali
Keyword(s):  
Reinforced Concrete ◽  
Ground Motions ◽  
Seismic Intensity ◽  
Shear Reinforcement ◽  
Dynamic Reliability ◽  
Moment Resisting Frames ◽  
Collapse Probability ◽  
Seismic Collapse ◽  
Moment Resisting ◽  
Column Joint

FEMA-P695 procedure was applied for seismic collapse safety evaluation of reinforced concrete moment resisting frames with/without beam-column joint detailing common in Pakistan. The deficient frame lacks shear reinforcement in joints and uses concrete of low compressive strength. Shake-table tests were performed on 1:3 reduced scale two-story models, to understand the progressive inelastic response of chosen frames and calibrate the inelastic finite-element based models. The seismic design factors i.e. response modification coefficient, overstrength, ductility, and displacement amplification factors (R, W0, Rμ, Cd) were quantified. Response modification factor R = 7.05 was obtained for the frame with beam-column joint detailing while R = 5.30 was obtained for the deficient frame. The corresponding deflection amplification factor Cd/R was found equal to 0.82 and 1.03, respectively. A suite of design spectrum compatible accelerograms was obtained from PEER strong ground motions for incremental dynamic analysis of numerical models. Collapse fragility functions were developed using a probabilistic nonlinear dynamic reliability-based method. The collapse margin ratio (CMR) was calculated as the ratio of seismic intensity corresponding to the 50th percentile collapse probability to the seismic intensity corresponding to the MCE level ground motions. It was critically compared with the acceptable CMR (i.e. the CMR computed with reference to a seismic intensity corresponding to the 10% collapse probability instead of MCE level ground motions). Frame with shear reinforcement in beam-column joints has achieved CMR 11% higher than the acceptable thus passing the criterion. However, the deficient frame achieved CMR 29% less than the conforming frame. This confirms the efficacy of beam-column joint detailing in reducing collapse risk.

Seismic collapse performance of special moment steel frames with torsional irregularities

2017 ◽  
Vol 141 ◽  
pp. 482-494 ◽  
Author(s):  
Sang Whan Han ◽  
Tae-O Kim ◽  
Dong Hwi Kim ◽  
Seong-Jin Baek
Keyword(s):  
Steel Frames ◽  
Seismic Collapse

scholarly journals Thin-Walled CFST Columns for Enhancing Seismic Collapse Performance of High-Rise Steel Frames

2017 ◽  
Vol 7 (1) ◽  
pp. 53 ◽  
Author(s):  
Yongtao Bai ◽  
Jiantao Wang ◽  
Yashuang Liu ◽  
Xuchuan Lin
Keyword(s):  
Steel Frames ◽  
High Rise ◽  
Seismic Collapse ◽  
Thin Walled ◽  
Cfst Columns

scholarly journals Assessing Seismic Collapse Safety and Retrofitting Low-Ductility RC Frame Structures on the Basis of the Acceptable Collapse Safety Margin in China

2020 ◽  
Vol 10 (4) ◽  
pp. 1238
Author(s):  
Lina Xian ◽  
Haiqing Liu ◽  
Zhongwei Zhao ◽  
Ni Zhang
Keyword(s):  
Cross Sections ◽  
Safety Margin ◽  
Frame Structure ◽  
Rc Frame ◽  
Collapse Probability ◽  
Rc Frame Structure ◽  
Collapse Resistance ◽  
Seismic Collapse ◽  
Before And After ◽  
Rc Frame Structures

The relationship between the average annual collapse probability and collapse safety margin of structures is identified to evaluate structural collapse performance quantitatively. A method is then proposed to determine the acceptable collapse margin ratio (CMR) with a certain annual collapse probability. Two methods, namely adopting steel braces and enlarging column cross sections, are used to retrofit a four-story, low-ductility reinforced concrete (RC) frame structure. On the basis of the acceptable CMR, the seismic collapse resistance of the structure is assessed before and after strengthening. Furthermore, a four-story RC frame structure, which is designed in conformity to the minimum design criteria of the building code, is constructed. The incremental dynamic analysis method is used in consideration of collapse uncertainties. Results show that when the acceptable annual collapse probability is equal to 1.24 × 10−4, which is calculated using the collapse probability at maximum considered earthquake (5%, as proposed in CECS 392), the collapse safety margin of the four structures does not satisfy the seismic collapse resistance requirements with large collapse uncertainty. The structures that are retrofitted and designed in conformity to the code can satisfy the collapse safety margin requirements when the acceptable annual collapse probability is increased to 2 × 10−4. The comparison of the two retrofitting schemes used to improve the seismic collapse resistance of the structure indicates that the steel brace-retrofitting method is better than increasing the column section. This work is an important reference for the reinforcement of the seismic resistance of structures and for corresponding research on collapse resistance.

Seismic collapse assessment of K-shaped bracings in cold-formed steel frames

Structures ◽  
2020 ◽  
Vol 25 ◽  
pp. 256-267
Author(s):  
Hossein Tajmir Riahi ◽  
Mehran Zeynalian ◽  
Amin Rabiei ◽  
Ehsan Ferdosi
Keyword(s):  
Steel Frames ◽  
Seismic Collapse ◽  
Cold Formed Steel ◽  
Collapse Assessment

Discrete optimization of semi-rigid steel frames in second-order analysis

2019 ◽  
Author(s):  
Marcos Henrique Bossardi Borges ◽  
Adelano Esposito ◽  
Herbert Gomes
Keyword(s):  
Discrete Optimization ◽  
Steel Frames ◽  
Second Order ◽  
Order Analysis
Sign in / Sign up

Export Citation Format

Share Document