scholarly journals Seismic Reliability Assessment of Base-Isolated Bridges in Quebec

2021 ◽  
Author(s):  
Mohamad Nassar ◽  
Lotfi Guizani ◽  
Marie-José Nollet ◽  
Antoine Tahan
Keyword(s):  
Seismic Hazard ◽  
Limit State ◽  
Large Temperature ◽  
Limit States ◽  
Seismic Reliability ◽  
Reliability Indices ◽  
Displacement Capacity ◽  
The Monte Carlo Method ◽  
Isolated Bridge ◽  
Isolated Bridges

The aim of this work is to estimate the seismic reliability of a simple typical two span lifeline base-isolated bridge designed to behave essentially elastic or as per the Canadian Highway Bridge Design Code, for seven localities in Quebec. Two limit states are considered for possible failure due to unacceptable damage: by flexure at pier-base and by displacement within the SIS. Main problem random variables (RVs) considered and modeled are: Seismic hazard, temperature, pier base dimensions and material mechanical properties. The Monte-Carlo method is used to evaluate each limit state reliability and probability of failure. Preliminary results reveal that notwithstanding the large temperature and seismic hazard variabilities between the seven sites in Quebec, the global reliability indices are almost uniform, around 3.45±0.02. Furthermore, security factor (i.e.1.25) on SIS displacement capacity results in reliability indices for SIS displacement are not levelled with the flexural reliability indices and needs further exam and consideration.

scholarly journals Seismic Reliability-Based Design Approach for Base-Isolated Systems in Different Sites

2020 ◽  
Vol 12 (6) ◽  
pp. 2400
Author(s):  
Paolo Castaldo ◽  
Tatiana Ferrentino
Keyword(s):  
Seismic Hazard ◽  
Structural Properties ◽  
Limit State ◽  
Large Data ◽  
Design Approach ◽  
Data Set ◽  
Ductility Demand ◽  
Seismic Reliability ◽  
Reliability Based Design ◽  
Inelastic Structures

This study employs the seismic reliability-based design approach for inelastic structures isolated by friction pendulum isolators, considering two different highly seismic Italian sites to provide useful design recommendations. Incremental dynamic analyses are carried out to estimate the seismic fragility of the superstructure and of devices, assuming different structural properties and limit state thresholds. Finally, considering seismic hazard curves of the investigated sites, seismic reliability-based design curves are proposed to derive the dimensions in plan of devices and the ductility demand of the superstructure as a function of both the structural properties and the reliability level expected. The proposed results confirm the possibility of using seismic reliability-based design as a sustainable and applicable approach and represent a large data set to adopt this design methodology in any site with a similar seismic hazard.

Displacement-Based Fragility Curves for Seismic Assessment of Adobe Buildings in Cusco, Peru

2012 ◽  
Vol 28 (2) ◽  
pp. 759-794 ◽  
Author(s):  
Nicola Tarque ◽  
Helen Crowley ◽  
Rui Pinho ◽  
Humberto Varum
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Response Spectrum ◽  
Limit State ◽  
Seismic Demand ◽  
Limit States ◽  
Plane Failure ◽  
Displacement Capacity ◽  
Out Of Plane ◽  
Displacement Based

The seismic vulnerability of single-story adobe dwellings located in Cusco, Peru, is studied based on a mechanics-based procedure, which considers the analysis of in-plane and out-of-plane failure mechanisms of walls. The capacity of each dwelling is expressed as a function of its displacement capacity and period of vibration and is evaluated for different limit states to damage. The seismic demand has been obtained from several displacement response spectral shapes. From the comparison of the capacity with the demand, probabilities of limit state exceedance have been obtained for different PGA values. The results indicate that fragility curves in terms of PGA are strongly influenced by the response spectrum shape; however, this is not the case for the derivation of fragility curves in terms of limit state spectral displacement. Finally, fragility curves for dwellings located in Pisco, Peru, were computed and the probabilities of limit state exceedance were compared with the data obtained from the 2007 Peruvian earthquake.

PSHA software review based on the Monte Carlo method

2020 ◽  
pp. 14-24
Author(s):  
V.A. Mironov ◽  
S.A. Peretokin ◽  
K.V. Simonov
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Seismic Hazard ◽  
Hazard Analysis ◽  
Software Review ◽  
Seismic Hazard Analysis ◽  
Probabilistic Seismic Hazard ◽  
Test Calculation ◽  
Seismic Surveys ◽  
The Monte Carlo Method

The article is a continuation of the software research to perform probabilistic seismic hazard analysis (PSHA) as one of the main stages in engineering seismic surveys. The article provides an overview of modern software for PSHA based on the Monte Carlo method, describes in detail the work of foreign programs OpenQuake Engine and EqHaz. A test calculation of seismic hazard was carried out to compare the functionality of domestic and foreign software.

Reliability and reliability-based sensitivity analysis of self-centering buckling restrained braces using meta-models

2021 ◽  
pp. 1045389X2110263
Author(s):  
Seyede Vahide Hashemi ◽  
Mahmoud Miri ◽  
Mohsen Rashki ◽  
Sadegh Etedali
Keyword(s):  
Failure Probability ◽  
Limit State ◽  
Computational Cost ◽  
Sensitivity Analyses ◽  
State Function ◽  
Reliability Indices ◽  
Buckling Restrained Brace ◽  
Polynomial Response Surface ◽  
Nonlinear Dynamic Analyses ◽  
High Computational Cost

This paper aims to carry out sensitivity analyses to study how the effect of each design variable on the performance of self-centering buckling restrained brace (SC-BRB) and the corresponding buckling restrained brace (BRB) without shape memory alloy (SMA) rods. Furthermore, the reliability analyses of BRB and SC-BRB are performed in this study. Considering the high computational cost of the simulation methods, three Meta-models including the Kriging, radial basis function (RBF), and polynomial response surface (PRSM) are utilized to construct the surrogate models. For this aim, the nonlinear dynamic analyses are conducted on both BRB and SC-BRB by using OpenSees software. The results showed that the SMA area, SMA length ratio, and BRB core area have the most effect on the failure probability of SC-BRB. It is concluded that Kriging-based Monte Carlo Simulation (MCS) gives the best performance to estimate the limit state function (LSF) of BRB and SC-BRB in the reliability analysis procedures. Considering the effects of changing the maximum cyclic loading on the failure probability computation and comparison of the failure probability for different LSFs, it is also found that the reliability indices of SC-BRB were always higher than the corresponding reliability indices determined for BRB which confirms the performance superiority of SC-BRB than BRB.

Combined flexure and torsion of I-shaped steel beams

1989 ◽  
Vol 16 (2) ◽  
pp. 124-139 ◽  
Author(s):  
Robert G. Driver ◽  
D. J. Laurie Kennedy
Keyword(s):  
Limit State ◽  
Bending Moment ◽  
Phase Behaviour ◽  
Inelastic Interaction ◽  
Steel Beams ◽  
Ultimate Limit State ◽  
Second Phase ◽  
Design Standards ◽  
Limit States ◽  
Interaction Diagram

Design standards provide little information for the design of I-shaped steel beams not loaded through the shear centre and therefore subjected to combined flexure and torsion. In particular, methods for determining the ultimate capacity, as is required in limit states design standards, are not presented. The literature on elastic analysis is extensive, but only limited experimental and analytical work has been conducted in the inelastic region. No comprehensive design procedures, applicable to limit states design standards, have been developed.From four tests conducted on cantilever beams, with varying moment–torque ratios, it is established that the torsional behaviour has two distinct phases, with the second dominated by second-order geometric effects. This second phase is nonutilizable because the added torsional restraint developed is path dependent and, if deflections had been restricted, would not have been significant. Based on the first-phase behaviour, a normal and shearing stress distribution on the cross section is proposed. From this, a moment–torque ultimate strength interaction diagram is developed, applicable to a number of different end and loading conditions. This ultimate limit state interaction diagram and serviceability limit states, based on first yield and on distortion limitations, provide a comprehensive design approach for these members. Key words: beams, bending moment, flexure, inelastic, interaction diagram, I-shaped, limit states, serviceability, steel, torsion, torque, ultimate.

Anchor rod forces and maximum bending moments in sheet pile walls using the factored strength approach

1996 ◽  
Vol 33 (5) ◽  
pp. 815-821 ◽  
Author(s):  
A B Schriver ◽  
A J Valsangkar
Keyword(s):  
Water Pressure ◽  
Limit State ◽  
Bending Moment ◽  
Ultimate Limit State ◽  
Sheet Pile ◽  
Limit States ◽  
Working Stress ◽  
Geotechnical Design ◽  
Ultimate Limit State Design ◽  
Sheet Pile Wall

Recently, the limit states approach using factored strength has been recommended in geotechnical design. Some recent research has indicated that the application of limit states design using recommended load and strength factors leads to conservative designs compared with the conventional methods. In this study the influence of sheet pile wall geometry, type of water pressure distribution, and different methods of analysis on the maximum bending moment and achor rod force are presented. Recommendations are made to make the factored strength design compatible with conventional design. Key words: factored strength, working stress design, ultimate limit state design, anchored sheet pile wall, bending moment, anchor rod force.

Safe Platooning Headways on Girder Bridges

2021 ◽  
pp. 036119812110363
Author(s):  
Bowen Yang ◽  
Joshua S. Steelman ◽  
Jay A. Puckett ◽  
Daniel G. Linzell
Keyword(s):  
Prestressed Concrete ◽  
Limit State ◽  
Live Load ◽  
Load Effect ◽  
Operational Strategies ◽  
Reliability Indices ◽  
Girder Bridges ◽  
Legal Limits ◽  
Weigh In Motion ◽  
Load And Resistance Factor

Truck platooning—digitally linking two or more trucks to travel in a closely spaced convoy—is an emerging technology with the potential to save fuel and reduce labor. A framework is described to determine how much a platoon permit load might be increased above Federal Bridge Formula B legal limits, given strict control over the load characteristics and operational tactics. Soon, platoons are expected to advance not only with respect to traffic operations but also in their ability to weigh and report axle weight and spacing, functioning as mobile weigh-in-motion vehicles. Consequently, platoon live load statistics (bias and coefficient of variation) can differ from code assumptions, and are perhaps controllable, which poses a significant opportunity with respect to operational strategies. A parametric study is presented that examined safe headways between platooning trucks, considering different girder spacings, span lengths, numbers of spans, types of structure, truck configurations, numbers of trucks, and adjacent lane loading scenarios. The Strength I limit state was evaluated for steel and prestressed concrete I-girder bridges optimally designed using load and resistance factor design. Reliability indices, β, were calculated for each load case based on Monte Carlo simulation. Summary headway guidance was developed and is presented here to illustrate potential safe operational strategies for varying truck weights and platoon live load effect uncertainties.

Influence of Human Error on Structural Reliability

2017 ◽  
Author(s):  
Eric Brehm ◽  
Robert Hertle ◽  
Markus Wetzel
Keyword(s):  
Human Error ◽  
Structural Reliability ◽  
Failure Modes ◽  
Structural Model ◽  
Limit State ◽  
Design Procedure ◽  
Material Strength ◽  
Limit States ◽  
The Impact

In common structural design, random variables, such as material strength or loads, are represented by fixed numbers defined in design codes. This is also referred to as deterministic design. Addressing the random character of these variables directly, the probabilistic design procedure allows the determination of the probability of exceeding a defined limit state. This probability is referred to as failure probability. From there, the structural reliability, representing the survival probability, can be determined. Structural reliability thus is a property of a structure or structural member, depending on the relevant limit states, failure modes and basic variables. This is the basis for the determination of partial safety factors which are, for sake of a simpler design, applied within deterministic design procedures. In addition to the basic variables in terms of material and loads, further basic variables representing the structural model have to be considered. These depend strongly on the experience of the design engineer and the level of detailing of the model. However, in the clear majority of cases [1] failure does not occur due to unexpectedly high or low values of loads or material strength. The most common reasons for failure are human errors in design and execution. This paper will provide practical examples of original designs affected by human error and will assess the impact on structural reliability.

Mechanical Analysis for the Assessment of the Seismic Capacity of Masonry Buildings’ Classes in the City Centre of Sulmona (Italy)

2010 ◽  
Vol 133-134 ◽  
pp. 623-628
Author(s):  
Marco Munari ◽  
Gianluca Busolo ◽  
Maria Rosa Valluzzi
Keyword(s):  
Mechanical Analysis ◽  
City Centre ◽  
Masonry Buildings ◽  
Seismic Capacity ◽  
Limit States ◽  
Damage Level ◽  
Capacity Curves ◽  
Perfectly Plastic ◽  
Displacement Capacity ◽  
Comparison Of The Results

A mechanical based method for the evaluation of the seismic capacity of masonry buildings’ classes in terms of damage limit states is presented: the purpose of the study is to achieve, in the framework of vulnerability analyses at territorial scale, reliable values for the damage level of vulnerability classes of masonry buildings, depending on the seismic input level. This approach is, in fact, designed as a “1st level” tool based on easily traceable information provided by expeditious surveys. Once identified a limited number of typological, physical and mechanical parameters that are necessary to define each vulnerability class, a significant number of simplified models of masonry buildings belonging to each class has been created. Non-linear static analysis of these models allowed the creation of bilinear elastic perfectly plastic capacity curves: the displacement capacity described by these curves is related with the actual displacement values required by seismic intensities associated to different return periods. It is so possible to identify, for different vulnerability classes and different seismic inputs, the loss of capacity in terms of damage level of each building. An application of the method to models representative of masonry buildings in the historical centre of Sulmona, in L’Aquila province, and a comparison of the results with others obtained with other methodologies of assessment are presented.

A Study on the Restrainer for Isolated Bridge

2011 ◽  
Vol 243-249 ◽  
pp. 5208-5213
Author(s):  
Yong Feng Du ◽  
Xiao Yu Sun
Keyword(s):  
Lateral Displacement ◽  
Time History ◽  
Nonlinear Characteristics ◽  
Isolation System ◽  
Finite Element Software ◽  
Continuous Beam Bridge ◽  
History Analysis ◽  
Isolated Bridge ◽  
Isolated Bridges ◽  
Beam Bridge

As a result of adopting isolated bearings, it is inevitable to increase the lateral displacement of the superstructure and the chance of girder falling. However, the shear keys that just satisfies the structural design is far from meeting the requirements of displacement of isolated bridge restrictions. On account of this, given the nonlinear characteristics of bearings and the restrainer, the authors make the study on the "damping rubber with coupling collar" restrainer, and then establish isolation system model of continuous beam bridge with finite element software named Midas. Meanwhile, the effect of the restrainer on the dynamic response of isolated bridges is presented by time-history analysis, which reveals the great value in the application of limiting displacement of isolated bridge.

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