scholarly journals Seismic Fragility And Post-Earthquake Reparability of Concrete Frame With Low-Bond High-Strength Rebar Reinforced Concrete Column

2021 ◽  
Author(s):  
Junhua Wang ◽  
Y.P. Sun
Keyword(s):  
Fragility Curves ◽  
Residual Deformation ◽  
High Strength ◽  
Seismic Fragility ◽  
Present Calculation ◽  
Reinforced Concrete Column ◽  
Seismic Behaviour ◽  
Earthquake Intensity ◽  
Lateral Drift ◽  
Seismic Collapse

Abstract To further study the global seismic behaviour and post-earthquake reparability of RC building frames with the proposed self-centring columns with low-bond high-strength reinforcements (LBHSRs), incremental dynamic analysis (IDA) of five-floor and ten-floor frame archetypes under excitation by twenty ground motions (GMs) was performed. First, the pushover results indicated that the use of LBHSR could substantially improve the yield and ultimate lateral drift of both the archetypes, although the archetype had a smaller longitudinal reinforcement ratio (LR) of the LBHSR and similar seismic resistance. The dynamic response results indicated that the archetype with LBHSRs exhibited a smaller residual story lateral drift although the effectiveness of the use of LBHSR to reduce seismic response was not apparent for the archetype subjected to a low-intensity earthquake. The seismic fragility results showed that LBHSR was more effective for preventing seismic collapse than for attaining the immediate occupancy (IO), life safety (LS), and collapse prevention (CP) limit states. Furthermore, the higher the LR, the lower was the likelihood of seismic collapse. The fragility curves of the residual story lateral drifts indicate that the use of LBHSR can significantly mitigate the residual deformation in the DS1, DS2, and DS3 damage states. Moreover, the effectiveness increases with the increase in the LR and earthquake intensity. Comparisons of residual story lateral drifts between the predicted results and IDA results indicated that the present calculation models are not suitable for predicting residual deformation. The model needs to be studied further.

Behaviour of slender concrete shear walls with high-strength reinforcement under reversed cyclic loading.

2021 ◽  
Author(s):  
Nima Aghniaey ◽  
Murat Saatcioglu ◽  
Hassan Aoude
Keyword(s):  
Large Scale ◽  
Shear Walls ◽  
High Strength ◽  
Shear Wall ◽  
Analytical Investigation ◽  
Seismic Behaviour ◽  
Drift Capacity ◽  
Lateral Drift ◽  
Experimental Findings ◽  
Reversed Cyclic

Research on seismic behaviour of shear walls with high-strength steel is limited. A combined experimental and analytical investigation was conducted to assess seismic behaviour of flexure-dominant shear walls. A large-scale concrete shear wall with Grade 690 MPa (ASTM A1035) reinforcement and 84 MPa concrete was tested under simulated seismic loading. The wall was a ¼ -scale of a 6-storey shear wall, with 4.53 m height and 1.45 m length. It sustained a lateral drift of 1.8% prior to developing failure due to the rupturing of longitudinal reinforcement. This is 35% less than the drift capacity of a companion wall reinforced with 400 MPa reinforcement tested earlier. VecTor2 software was used to conduct an analytical parametric study to expand the experimental findings. The results indicate that the reinforcement grade has a significant impact on strength, ductility and hysteretic behaviour of shear walls.

Damage State Identification and Seismic Fragility Evaluation of the Underground Tunnels

2015 ◽  
Vol 775 ◽  
pp. 274-278
Author(s):  
Thai Son Le ◽  
Jung Won Huh ◽  
Jin Hee Ahn ◽  
Achintya Haldar
Keyword(s):  
Fragility Curves ◽  
Sampling Technique ◽  
Latin Hypercube Sampling ◽  
Assessment Method ◽  
Maximum Likelihood Estimates ◽  
Seismic Fragility ◽  
Large Set ◽  
Earthquake Intensity ◽  
Damage State ◽  
Design Spectrum

An efficient seismic fragility assessment method is proposed for underground tunnel structures in this paper. The ground response acceleration method for buried structure (GRAMBS), an efficient quasi-static method considering soil-structure interaction (SSI) effect, is used in the proposed approach to estimate the dynamic response behavior of the underground tunnels. In addition, the pushover analyses are conducted to identify the damage states of tunnels and Latin Hypercube sampling technique is used to consider uncertainties in the design variables. A large set of artificially generated ground motions satisfying a design spectrum for specific earthquake intensity are generated and fragility curves are developed. The seismic fragility curves are represented by two-parameter lognormal distribution function and its two parameters, namely the median and log-standard deviation, are estimated using the maximum likelihood estimates method.

Seismic fragility assessment of bridge piers incorporating high-strength steel reinforcement and concrete under near-fault ground motions

2020 ◽  
Author(s):  
Saif Aldabagh ◽  
Saqib Khan ◽  
M. Shahria Alam
Keyword(s):  
High Strength Steel ◽  
Load Capacity ◽  
Fragility Curves ◽  
Time History ◽  
Inelastic Strain ◽  
High Strength ◽  
The United States ◽  
Bridge Piers ◽  
Seismic Fragility ◽  
Damage States

Design codes in the United States and Canada limit the use of high-strength steel (HSS) and high-strength concrete (HSC) to bridge components that are expected to remain elastic during a seismic event. Although HSS and HSC have higher tensile and compressive strengths, respectively, their lower inelastic strain capacities impose for such restrictions. To assess the seismic performance of HSS and HSC, the pier of an existing bridge is redesigned using concrete compressive strength of 50 and 80 MPa, and reinforcement yield strength of 420, 690, and 830 MPa. Static pushover and nonlinear dynamic time-history analyses were performed to generate force-deformation and seismic fragility curves. Bridge piers incorporating HSS and HSC attained the maximum load capacity yet were the least ductile. They were less seismically vulnerable than those incorporating conventional materials at minimal and repairable damage states, but not at extensive and probable replacement damage states.

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.

scholarly journals Fragility curves for Italian URM buildings based on a hybrid method

2021 ◽  
Author(s):  
A. Sandoli ◽  
G. P. Lignola ◽  
B. Calderoni ◽  
A. Prota
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Limit State ◽  
Ultimate Limit State ◽  
Masonry Building ◽  
Masonry Buildings ◽  
Seismic Behaviour ◽  
Building Stock ◽  
Ground Acceleration ◽  
Damage Scenario

AbstractA hybrid seismic fragility model for territorial-scale seismic vulnerability assessment of masonry buildings is developed and presented in this paper. The method combines expert-judgment and mechanical approaches to derive typological fragility curves for Italian residential masonry building stock. The first classifies Italian masonry buildings in five different typological classes as function of age of construction, structural typology, and seismic behaviour and damaging of buildings observed following the most severe earthquakes occurred in Italy. The second, based on numerical analyses results conducted on building prototypes, provides all the parameters necessary for developing fragility functions. Peak-Ground Acceleration (PGA) at Ultimate Limit State attainable by each building’s class has been chosen as an Intensity Measure to represent fragility curves: three types of curve have been developed, each referred to mean, maximum and minimum value of PGAs defined for each building class. To represent the expected damage scenario for increasing earthquake intensities, a correlation between PGAs and Mercalli-Cancani-Sieber macroseismic intensity scale has been used and the corresponding fragility curves developed. Results show that the proposed building’s classes are representative of the Italian masonry building stock and that fragility curves are effective for predicting both seismic vulnerability and expected damage scenarios for seismic-prone areas. Finally, the fragility curves have been compared with empirical curves obtained through a macroseismic approach on Italian masonry buildings available in literature, underlining the differences between the methods.

scholarly journals An approach to derive seismic fragility curves

2021 ◽  
Vol 1026 (1) ◽  
pp. 012007
Author(s):  
V J Vedhanayaghi ◽  
M Manoharan ◽  
J Jasper Daniel ◽  
S Premkumar ◽  
S ArunBharathi
Keyword(s):  
Fragility Curves ◽  
Seismic Fragility

Seismic Performance of High Titanium Heavy Slag High Strength Concrete Columns

2012 ◽  
Vol 174-177 ◽  
pp. 455-459 ◽  
Author(s):  
Xiao Wei Li ◽  
Xue Wei Li ◽  
Xin Yuan
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
High Strength Concrete ◽  
Load Ratio ◽  
High Strength ◽  
Scale Model ◽  
Transverse Reinforcement ◽  
Reinforced Concrete Column ◽  
Displacement Ductility ◽  
Strength Concrete

For expedite the development of high titanium heavy slag concrete, eight high titanium heavy slag high strength reinforced concrete (HTHS-HSRC) scale model column are studied. The eight HTHS-HSRC model columns are tested under reversed horizontal force. Primary experimental parameters include axial load ratio varying from 0.3 to 0.5, volumetric ratios of transverse reinforcement ranging from 1.38% to 1.56%, strength of high titanium heavy slag high strength concrete varying from 55.9 to 61.6 N/mm2 and configurations of transverse reinforcement. It is found from the test result that HTHS-HSRC model columns provides comparable seismic performance to those usually used reinforced concrete column in terms of member ductility, hysteretic and energy dissipation capacity. Primary Factors of Displacement Ductility of Model Columns are also discussed.

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