INVESTIGATION OF SEISMIC DAMAGE OF CABLE-STAYED BRIDGES WITH DIFFERENT CONNECTION CONFIGURATION

2009 ◽  
Vol 03 (03) ◽  
pp. 227-247 ◽  
Author(s):  
HUI LI ◽  
JINLONG LIU ◽  
JINPING OU
Keyword(s):  
Failure Modes ◽  
Plastic Hinge ◽  
Damage Index ◽  
Seismic Damage ◽  
Damage Indices ◽  
Floating System ◽  
Energy Dissipation System ◽  
Damage Condition ◽  
Seismic Behaviors ◽  
Cable Stayed Bridges

In this paper, the seismic behaviors of three cable-stayed bridges with different structural systems including Rigid System (RS), Floating System (FS) and Passive Energy Dissipation System (PEDS) are studied. The results show that the seismic behaviors of these bridges are so different even under the same earthquake. Based on damage analysis of the towers, failure modes of the three different systems are concluded. For RS, the bottom of the middle tower is a vulnerable region, implying that the failure mainly focuses here and plastic hinge forms under earthquake. The FS is damaged most severely, in which the edge tower has a larger damage index than that of middle tower. While the seismic responses of PEDS decrease dramatically compared to FS due to the incorporation of viscous dampers and the damage indices for all towers are small. The seismic damage condition between the middle tower and the edge tower can be adjusted by changing the damping coefficient of the viscous damper.

scholarly journals Hybrid backpropagation neural network-particle swarm optimization for seismic damage building prediction

2019 ◽  
Vol 14 (1) ◽  
pp. 360
Author(s):  
Marina Yusoff ◽  
Faris Mohd Najib ◽  
Rozaina Ismail
Keyword(s):  
Neural Network ◽  
Particle Swarm Optimization ◽  
Damage Index ◽  
Particle Swarm ◽  
Seismic Damage ◽  
Backpropagation Neural Network ◽  
Swarm Optimization ◽  
Local Optima ◽  
Damage Indices ◽  
Prediction Problems

The evaluation of the vulnerability of buildings to earthquakes is of prime importance to ensure a good plan can be generated for the disaster preparedness to civilians. Most of the attempts are directed in calculating the damage index of buildings to determine and predict the vulnerability to certain scales of earthquakes. Most of the solutions used are traditional methods which are time consuming and complex. Some of initiatives have proven that the artificial neural network methods have the potential in solving earthquakes prediction problems. However, these methods have limitations in terms of suffering from local optima, premature convergence and overfitting. To overcome this challenging issue, this paper introduces a new solution to the prediction on the seismic damage index of buildings with the application of hybrid back propagation neural network and particle swarm optimization (BPNN-PSO) method. The prediction was based on damage indices of 35 buildings around Malaysia. The BPNN-PSO demonstrated a better result of 89% accuracy compared to the traditional backpropagation neural network with only 84%. The capability of PSO supports fast convergence method has shown good effort to improve the processing time and accuracy of the results.

Seismic Damage Assessment of Regular Gravity Design Buildings

2013 ◽  
Vol 569-570 ◽  
pp. 294-301
Author(s):  
Caterina Negulescu ◽  
Kushan K. Wijesundara ◽  
Evelyne Foerster
Keyword(s):  
Damage Assessment ◽  
Failure Modes ◽  
Limit State ◽  
Damage Index ◽  
Ductile Failure ◽  
Ultimate Limit State ◽  
Natural Period ◽  
Damage Indices ◽  
Seismic Damage Assessment ◽  
Assessment Results

During the past earthquakes, different low ductile failure modes are observed in the gravity design structures and thus, the most of existing damage indices may fail to assess the damage of gravity design structures accurately in referring to the two main performance levels: immediate occupancy and ultimate limit state. Therefore, this study investigates the possible damage indices for the damage assessment of gravity design frames. For this purpose, among the existing damage indices in the literature, this study considers the inter-story drift and the natural period based damage indices. In addition, two new damage indices based on the wavelet based energy and the dominant inelastic period of a building are also considered in this study. Furthermore, the damage assessment results from the four damage indices for three gravity design buildings are compared and discussed. From the comparison, linear correlations between the inter-storey drift based damage index and the wavelet energy based index, and dominant inelastic period based damage index are observed. Finally, this study concludes based on the observations that no significant effects of number of inelastic cycles to the damage assessment results for low ductile structures. However, this study also highlights the effects of number of inelastic cycles to the damage for medium and high ductile structures.

Experimental Study on Seismic Damage Model of the SRHSHPC Composite Frame Columns

2008 ◽  
Vol 385-387 ◽  
pp. 145-148
Author(s):  
Shan Suo Zheng ◽  
Liang Zhang ◽  
Lei Li ◽  
Bin Wang ◽  
Ming Xie
Keyword(s):  
Concrete Strength ◽  
Damage Model ◽  
Damage Index ◽  
Seismic Damage ◽  
Damage Development ◽  
Damage Models ◽  
Composite Frame ◽  
History Of ◽  
Reversed Loading ◽  
Seismic Behaviors

Based on experimental investigation under low cyclic reversed loading, the seismic behaviors and seismic damage model for steel reinforced high strength and high performance concrete (SRHSHPC) composite frame columns are studied. Several existing seismic damage models are firstly presented and their characteristics are comparatively analyzed. From the test results of low cyclic reversed loading, the variation history of cumulative dissipated hysteretic energy of the SRHSHPC composite frame columns under different loading cycle levels is figured out, and the influence of axial compression ratio, shear span ratio, stirrup ratio and concrete strength on the cumulative dissipated hysteretic energy is also discussed. The damage index of the SRHSHPC composite frame columns is compared according to the existing seismic damage models, and the seismic damage model adapted for the SRHSHPC composite frame columns is established. According to the variation history of the damage index under different loading cycle levels, the rule of damage development for the SRHSHPC composite frame columns is proposed. The influence of axial compression ratio, shear span ratio, stirrup ratio and concrete strength on the damage development is also discussed. The results indicate that the seismic behaviors of the SRHSHPC composite frame column are outstanding, and the seismic damage model could give a quantitative description for damaging process of the samples, which is reference for establishing more rational damage criteria for the SRHSHPC earthquake-resistant composite structure.

On-Line Time-Series Damage State Estimation Using Correlation Analysis and Ultrasonic Broadband Active Sensing

2009 ◽  
Author(s):  
Subhasish Mohanty ◽  
Jun Wei ◽  
Aditi Chattopadhyay ◽  
Pedro Peralta
Keyword(s):  
Time Series ◽  
Correlation Analysis ◽  
State Estimation ◽  
Damage Index ◽  
Active Sensing ◽  
Damage State ◽  
Damage Indices ◽  
Dual Sensor ◽  
Damage States ◽  
Damage Condition

This paper proposes an approach to estimate the fatigue-induced damage state of a metallic structure under biaxial cyclic load. An ultrasonic based technique for broadband active sensing is used. A novel damage index estimation technique based on dual sensor signals is developed that removes the contribution from high frequency input dependant noise. The scalar damage index at any particular damage condition is evaluated using a nonparametric system identification approach such as correlation analysis. The time series estimation of the damage indices (or damage states) shows good correlation with visual measurements of crack length. The time series 2σ error bound was also evaluated to study the effect of measurement noise on damage state estimation.

scholarly journals Earthquake Damage Assessment for RC Structures Based on Fuzzy Sets

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Haoxiang He ◽  
Maolin Cong ◽  
Yongwei Lv
Keyword(s):  
Reinforced Concrete ◽  
Damage Assessment ◽  
Pushover Analysis ◽  
Damage Index ◽  
Seismic Damage ◽  
Assessment Method ◽  
Energy Concentration ◽  
Fuzzy Evaluation ◽  
Damage Indices ◽  
Seismic Damage Assessment

A global damage index based on multiple linear force-deformation curves in pushover analysis is presented to evaluate the integrated damage of reinforced concrete structure. The modified coefficient is provided considering the cyclic load and hysteresis energy. The number of inelastic cycles and the coefficient of hysteresis energy concentration are also introduced as damage indices. Hence, multiple damage indices about displacement and energy for performance-based design are considered. The relation of multiple damage indices or factors and the fuzzy damage set is presented by comprehensive fuzzy evaluation; hence, a performance-based multiple fuzzy seismic damage-assessment method for reinforced concrete frame structures is established. The method can be accomplished based on pushover analysis, code spectrum, and capacity spectrum method. The fuzzy seismic damage-assessment method is verified through nonlinear analysis four different structures and the corresponding results and assessment conclusions are accurate.

scholarly journals Damage-Based Seismic Retrofitting Approach for Nonductile Reinforced Concrete Structures Using FRP Composite Wraps

2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Vui Van Cao ◽  
Son Quang Pham
Keyword(s):  
Plastic Hinge ◽  
Seismic Damage ◽  
Seismic Retrofitting ◽  
Engineering Practice ◽  
Similar Amount ◽  
Building Structures ◽  
Frp Composite ◽  
Damage Indices ◽  
Fibre Reinforced Polymer ◽  
Critical Locations

Applying similar amount of fibre reinforced polymer (FRP) for all plastic hinge locations in a structure is not an ideal approach as damage occurring at these critical locations may vary considerably. Building owners also always want to keep FRP retrofitting cost and associated interruption to a minimum. In this context, the current paper proposes an FRP retrofitting approach, in which FRP is selectively distributed based on the distribution of seismic damage in structures. The proposed approach, characterized by both quantitative and qualitative criteria, is simple but very effective in simultaneously reducing the seismic damage, amount of FRP to be used, and time of installation. For the considered cases of low- and mid-rise nonductile building structures, the FRP amount reduced approximately by 31% compared to the cases in which FRP was evenly distributed, leading to lower installation cost and less interruption time. Interestingly, although 31% FRP was saved, the damage indices of the FRP retrofitted frames were significantly lower than those in cases of even FRP distribution because FRP effectively served for critical locations. Due to its simplicity and technical/economical effectiveness, the proposed FRP retrofitting approach can be useful for engineering practice.

Study on shear performance of the connection with external stiffening ring between square steel tubular column and unequal-depth steel beams

2020 ◽  
pp. 136943322098166
Author(s):  
Shuhao Yin ◽  
Bin Rong ◽  
Lei Wang ◽  
Yiliang Sun ◽  
Wuchen Zhang ◽  
...  
Keyword(s):  
Failure Modes ◽  
Plastic Hinge ◽  
Steel Tube ◽  
Nonlinear Finite Element ◽  
Steel Beams ◽  
Finite Element Models ◽  
Test Results ◽  
Panel Zone ◽  
Load Paths ◽  
Shear Performance

This paper studies the shear performance of the connection with the external stiffening ring between the square steel tubular column and unequal-depth steel beams. Two specimens of interior column connections were tested under low cyclic loading. The deformation characteristics and failure modes exhibited by the test phenomena can be summarized as: (1) two specimens all exhibited shear deformation in steel tube web of the panel zone and (2) weld fracture in the panel zone and plastic hinge failure at beam end were observed. Besides, load-displacement behaviors and strain distributions have been also discussed. The nonlinear finite element models were developed to verify the test results. Comparative analyses of the bearing capacity, failure mode, and load-paths between the equal-depth and unequal-depth beam models have been carried out.

Seismic Damage Analysis on the Continuous Girder Bridge of Urban Rail Transit Line

2014 ◽  
Vol 488-489 ◽  
pp. 398-402 ◽  
Author(s):  
Hai Qing Li ◽  
Yong Jun Ni ◽  
Xin Gang Liu ◽  
Jin Xing Yan
Keyword(s):  
Seismic Performance ◽  
Evaluation Method ◽  
Research Direction ◽  
Seismic Damage ◽  
Urban Rail Transit ◽  
Rail Transit ◽  
Damage Analysis ◽  
Seismic Performance Evaluation ◽  
Damage Indices ◽  
Urban Rail

Seismic damage was the key reason which resulted in the serviceability degradation or collapse of the bridge. How to quantify the seismic damage and evaluate the seismic performance of the bridge under earthquakes through the damage analysis was the significant research direction in the performance based seismic design. In this paper the Park-Ang model (a well-known dual parameters model) and its modification version used for the damage evaluation of the concrete structure were compared. Furthermore, through the definition of the damage indices of the models based on the modified Park-Ang model and the descending slope of the IDA(incremental dynamic analysis) curve, the seismic damage levels of the typical bridge in the urban rail transit line under the designated earthquakes were analyzed, respectively. It was shown from the results that the calculated results from the two model was essentially consistent. The damage analysis based evaluation method was feasibly used for the seismic performance evaluation of the bridge.

Damage Accumulation and Life-Prediction Models for SnAgCu Leadfree Electronics Under Shock-Impact

2009 ◽  
Author(s):  
Pradeep Lall ◽  
Sandeep Shantaram ◽  
Arjun Angral ◽  
Mandar Kulkarni ◽  
Jeff Suhling
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Thermal Aging ◽  
Cohesive Zone ◽  
Life Prediction ◽  
Failure Modes ◽  
Damage Index ◽  
Image Correlation ◽  
Shock Impact ◽  
Cohesive Zone Elements

Relative damage-index based on the leadfree interconnect transient strain history from digital image correlation, explicit finite-elements, cohesive-zone elements, and component’s survivability envelope has been developed for life-prediction of two-leadfree electronic alloy systems. Life prediction of pristine and thermally-aged assemblies, have been investigated. Solder alloy system studied include Sn1Ag0.5Cu, and 96.5Sn3.5Ag. Transient strains during the shock-impact have been measured using digital image correlation in conjunction with high-speed cameras operating at 50,000 fps. Both the board strains and the package strains have been measured in a variety of drop orientations including JEDEC horizontal drop orientation, vertical drop orientation and intermediate drop orientations. In addition the effect of sequential stresses of thermal aging and shock-impact on the failure mechanisms has also been studied. The thermal aging condition used for the study includes 125°C for 100 hrs. The presented methodology addresses the need for life prediction of new lead-free alloy-systems under shock and vibration, which is largely beyond the state of art. Three failure modes have been predicted including interfacial failure at the copper-solder interface, solder-PCB interface, and the solder joint failure. Explicit non-linear finite element models with cohesive-zone elements have been developed and correlated with experimental results. Velocity data from digital image correlation has been used to drive the attachment degrees of freedom of the submodel and extract transient interconnect strain histories. Explicit finite-element sub-modeling has been correlated with the full-field strain in various locations, orientations, on both the package and the board-side. The survivability of the leadfree interconnections under sequential loading (thermal aging and shock-impact) from simulation has been compared with pristine circuit assemblies subjected to shock-impact. Sequential loading changes the failure modes and decreases the drop reliability as compared to the room temperature experimental results. Damage index based survivability envelope is intended for component integration to ensure reliability in harsh environments.

Failure Mechanism of Reinforced Concrete Rib Arch Bridge under Near-Fault Earthquakes

2011 ◽  
Vol 90-93 ◽  
pp. 940-945
Author(s):  
Wen Jun Gao ◽  
Guang Wu Tang ◽  
Yi Da Kong
Keyword(s):  
Reinforced Concrete ◽  
Nonlinear Response ◽  
Plastic Hinge ◽  
Seismic Damage ◽  
Arch Bridge ◽  
2008 Wenchuan Earthquake ◽  
Near Fault ◽  
Pulse Type ◽  
Near Fault Earthquakes ◽  
Far Fault

A typical reinforced concrete rib arch bridge was chosen to investigate its nonlinear response to near-fault ground motions recorded in 2008 Wenchuan earthquake. Results showed that significant seismic damage may occur, maximum demands were higher for near-fault records having forward directive than far-fault motions, and the rotational capacity of rib plastic hinge is not enough for the large compression force of arch rib. While backward-directivity motions, typically do not exhibit pulse-type motions, only have medium seismic damage to the arch bridge.

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