Damage Index Model Research Articles

Seismic performance of RC columns under combined cyclic flexural and constant axial loadings

In this study, an experimental test procedure is conducted to investigate seismic performance of reinforced concrete columns under earthquake loading. Earthquake loading is simulated by combination of constant axial load and reversing cyclic load. The main variables of the experimental program are selected to be dimensionless axial load level and the ratio of shear span to effective column depth. Test results are compared with the current suggestions and approximations used for performance-based design and/or evaluation of reinforced concrete (RC) columns under seismic loads. It is observed that section curvature plays an important role to express failure damage limit state under cyclic loading as well as to sudden decrease in load carrying capacity. Besides, two new simple suggestions are made for performance-based design and/or evaluation process of RC columns. As a first step of this suggestions, a relation between damage limit states and curvature ductility ratios of RC columns is defined. This relation is validated with the experimental results of test columns through damage index model based on section curvature. The proposed damage limit states vary according to damage level definition and based on buckling parameter in terms of diameter, buckling length and yield strength of longitudinal reinforcement. The second suggestion is made to relate damage limit state to decrease in shear resistance of columns. To this purpose, a model to express concrete contribution to shear strength due to the proposed damage limits is used. With these two new proposed equations, it is both aimed to obtain a damage limit state in terms of curvature ductility ratio and to control ductile failure mode in a simple yet effective way.

Comparison of RC girder bridge and building vulnerability considering empirical seismic damage

To explore the vulnerability of a reinforced concrete girder bridge and reinforced concrete building during an earthquake, and to compare the difference in the seismic capacity of the two types of engineering structures, the nonlinear vulnerability numerical and probabilistic model analysis methods were combined. Overall, 1069 reinforced concrete girder bridges and 949 reinforced concrete buildings damaged in the Wenchuan earthquake of May 12, 2008 were selected for vulnerability analysis. The vulnerability grades of damaged samples were evaluated according to the Chinese seismic intensity scale (CSIS-08), and the vulnerability matrix of reinforced concrete girder bridges and reinforced concrete buildings in multiple intensity regions was established. Moreover, the novel vulnerability comparison curve model was developed by considering the failure ratio and exceeding probability. The anomaly characteristics of seismic damage vulnerability between reinforced concrete girder bridges and reinforced concrete buildings under the influence of age, seismic design, the coupling of age and seismic design, and foundation type factors were compared and analysed. By employing the matrix calculation model of the mean damage index, the matrix and curve comparison model of the mean damage index vulnerability parameters of reinforced concrete girder bridges and reinforced concrete buildings in multiple intensity zones were developed.

Failure mechanism of underwater shield tunnel: An experimental and theoretical study

This study proposes a plastic hinge-based approach to investigate the failure mechanism of underwater shield tunnel lining structures. Joint plastic hinge and segmental plastic hinge are defined based on the observed failure patterns. The rotational demands of the plastic hinges are obtained through theoretical and numerical methods, and the locations of potential plastic hinges are determined based on the displacement requirement of the structure. A damage index model is used to evaluate the damage of the plastic hinges. Full-scale tests are conducted on two types of shield tunnel lining structures: straight-joint assembly structure (STRJS) and staggered-joint assembly structure (STGJS) under high-water pressure loading conditions. The test results indicate that the assembly method is found to significantly affect the failure pattern, with STRJS and STGJS failing through longitudinal joints and concrete segments, respectively. Furthermore, the STRJS and STGJS exhibit comparable load-bearing capacities, with ultimate loads of 2912 kN and 2867 kN, respectively. The plastic hinge approach is used to compare the failure mechanisms of STRJS and STGJS, revealing that STGJS has fewer joint plastic hinges than STRJS at the ultimate state of the shield tunnel lining structure. The failure of STRJS and STGJS is caused by the joint and segmental plastic hinges exceeding their rotation capacity, respectively. The study highlights the importance of considering the assembly method and the type of plastic hinge in the design of underwater shield tunnel lining structures.

Component damage‐based seismic fragility analysis of high‐rise building with transfer structure

SummaryFragility analysis is an effective tool used to assess the seismic risk of high‐rise buildings. During the process of fragility analysis, determining the engineering demand parameters (EDPs) corresponding to different damage states is of great importance as they directly influence the fragility results. However, for buildings with transfer structures, the EDPs corresponding to different damage levels are difficult to determine since the maximum demand in such buildings is mostly concentrated at the level of irregularity. Obtaining the fragility curves at component level (as used for bridge structures) may provide new insight into the seismic fragility analysis of buildings with transfer structures. Due to differences in structural systems and seismic response, it may be questionable whether such an approach can be directly applied to the fragility analysis of high‐rise buildings. In view of this, a component damage‐based approach suitable for high‐rise buildings and a detailed framework through which to obtain the fragility curves are proposed in this study. This method was applied to assess the seismic risk of a 34‐story concrete building with a transfer plate. The damage states for various structural components were obtained through a damage index (DI) model. The relationship between the DIs of the components and the maximum inter‐story drift ratios (MIDRs) was generated by cloud analysis, and MIDRs corresponding to different component damage states were obtained. The fragility curves at both component and system levels were evaluated. Numerical results indicate that, at the conservative level of PGA (0.2 g), the probability that the main components of the building incur irreparable damage is small, and the performance‐based seismic design requirements can be met.

Hysteretic behavior degeneration mechanism and damage evaluation of self-centering bridge pier system

Damage often occurs in the contact segment of self-centering (SC) bridge pier systems and significantly affects their hysteretic behavior under cyclic loading or seismic excitations. To quantify the degree of decline of the mechanical indices in the damaged SC bridge pier system, this study investigated the degeneration mechanism of the SC bridge pier system and its damage evaluation method. First, two damage modes, the resilient damage (RD) and brittle damage (BD) modes, are innovatively defined. Subsequently, the backward movement mechanism of the rotation point in the SC bridge pier system was investigated in detail, and the corresponding degradation mechanism of hysteretic behavior was specified in terms of experimental observation and mechanical analysis. Then, the application of hysteretic degradation mechanism was presented, and its correctness was verified using experimental data. Finally, a novel damage index (DI) specific to the SC bridge pier system, which can reasonably reflect key mechanical properties such as stiffness, yield carrying capacity, carrying capacity, and residual drift, is proposed and compared with existing DIs in terms of principle and evaluation effects. The results confirm that the proposed DI model can accurately evaluate the damage state of the SC bridge pier system.

Seismic Damage Evaluation of Beam-Column Joints in Monolithic Precast Concrete Frame Structures.

Quantitative calculation and evaluation of seismic damage are very important for structural safety, performance-based structural analysis, and seismic reinforcement. However, the relevant research results for precast concrete structures are extremely limited. In this paper, the seismic damage evaluation of beam-column joints in monolithic precast concrete frames was studied through cyclic loading tests and damage index calculation. The seismic damage process, load-displacement relationship, stiffness degradation, and the influence of axial compression ratio were analyzed, then the damage indexes were calculated and analyzed, and the quantitative evaluation of joint damage was conducted last. The results show that the connection seams can significantly affect the mechanical properties of precast joints, easily causing damage concentration, resulting in a lower bearing capacity and faster stiffness degradation compared with a cast-in-situ joint. A larger axial compression ratio can bring higher bearing capacity for the precast joints, and the peak load can be increased by 42.9% when the axial compression ratio is increased from 0.2 to 0.4. In contrast, the stiffness degradation will be accelerated with the increase in the axial compression ratio. From yield load to peak load, the stiffness of the precast joint with the largest axial compression ratio decreases by 46.0%, while the joint with the smallest axial compression ratio is only 36.4%. The damage index model adopted in this paper can accurately reflect the damage characteristics of the precast joints. The presented damage states based on the damage index calculation can accurately reflect the joint’s damage characteristics according to different stages. The paper realizes the quantitative damage evaluation for this kind of joint and provides a theoretical basis and method for further studies.

Damage index model and hysteretic viscous damping of masonry infill walls subjected to out-of-plane loadings

The definition of damage states for structural and non-structural elements is necessary to support the seismic vulnerability analyses and identify the most vulnerable elements that need to be retrofitted. The studies related to masonry infill walls focused on multiple experimental studies to characterize their in-plane and/or out-of-plane (OOP) behaviour. Some codes have already proposed damage states for masonry infill walls only under in-plane loadings. Also, the study of the normalized energy dissipation and the hysteretic viscous damping when subjected to OOP loadings were not explored. It is recognized that the OOP behaviour of masonry infill walls is still nowadays a topic needing further investigations. The main objective of this work is to propose damage index for infill walls under to pure OOP seismic loadings. For that, a detailed analysis of the damage observed in masonry infill walls tested under pure OOP loadings was performed. The damage observed in masonry infill walls made with different masonry units, with and without openings, is carefully detailed. After that, a pilot damage index model is proposed for masonry infill walls made of hollow clay horizontal brick units. The third objective of this work was the assessment and discussion of their normalized energy dissipation capacity and their hysteretic viscous damping. Some analytical formulations were proposed to estimate these parameters. A database containing thirteen OOP tests performed by three different authors was used to achieve these goals.

In-Service Reliability Assessment of Turbine Blade Thermal Barrier Coatings Based on a Novel Cumulative Damage Index Model

Abstract Thermal barrier coating (TBC) has been used widely on turbine blades to provide temperature and oxidation protection. With the turbine inlet temperature continuously increasing, TBCs have become more likely to oxide spallation, leading to premature failure of blade metal substrates. Thus, It is necessary to accurately evaluate the in-service reliability of TBCs for blade life assessment and engine operation safety. Nowadays, it is common to dynamically record aero-engine operating and performance data, called dynamic covariate data, which provides periodic snapshots for obtaining reliability information of engine components. Nevertheless, existing TBC life prediction models that pay adequate attention to dynamic covariate information are rare. This paper focuses on using limited failure samples with associated dynamic covariate data to make in-service reliability assessments of TBCs through a proposed cumulative damage index model. For the demonstration of the proposed approach, an integrated TBC life simulation approach has been introduced, which comprises engine performance, blade thermal, TBC damage, and damage accumulation models. The case study shows that the proposed cumulative damage index model-based method provides more stable and accurate results than the traditional statistical method based on failure-time data.

Wheel profile optimization procedure to minimize flange wear considering profile wear evolution

This study aims to develop a wheel profile optimization procedure to minimize flange wear considering the wear evolution. To this end, the wheel wear simulation capability is integrated into the profile optimization framework such that a total material loss can be minimized under design constraints. This allows for the wear reduction to be maintained over an extended traveling distance, while an optimized profile, minimizing the frictional energy for only the initial profile, would not ensure the optimum performance after the profile wear becomes significant. Furthermore, to enable a balanced mitigation of the profile wear and surface damage, the damage index model is introduced to the weighted objective function, considering profile wear evolution. Using flange wear tests with a scaled roller test rig, wear reduction of the optimized profile is experimentally validated. The wear simulation results agree with the test data. It is demonstrated that the flange wear and tread surface damages are reduced simultaneously over an extended traveling distance using the profile optimization procedure developed in this study.

Estimation of Seismic Damage Induced by Near- and Far-Fault Earthquakes Using Modified Equivalent Linearization Method of Mid-Rise RC Buildings

For the seismic design of a mid-rise reinforced concrete (RC) building considering the damage control, the main purpose of this work is to propose a simplified method that can be used to estimate the damage index or damage state induced by the near-fault and far-fault earthquakes. In addition to the maximum deformation response, the hysteretic energy dissipation induced the earthquakes is also considered in the damage index quantification based on the modified equivalent linearization method (MELM). Based on the damage index model in terms of the maximum deformation response and hysteretic energy dissipation under an earthquake, this work provides a convenient method by which an engineer can determine the damage-controlling minimal ductility requirement to ensure that the damage index remains under a specified value. For a mid-rise RC building structure, an engineer can also apply the simplified formula proposed in this work to obtain the damage-controlling yielding strength for a specified ductility capacity.

A novel remote sensing detection method for buildings damaged by earthquake based on multiscale adaptive multiple feature fusion

The rapid and accurate detection of damaged buildings after an earthquake are critical for emergency response. Given the difference in the textures of damaged parts and those of the original buildings, damaged buildings can be accurately detected through textural heterogeneity. However, quantitatively detecting damaged buildings using such heterogeneity from post-earthquake images is difficult. Therefore, we propose a method of automatically extracting house damage information from post-quake high-resolution optical remote sensing imagery through the multiscale fusion of spectral and textural features, which can be achieved in three steps. Firstly, the textural and spectral features of the images are enhanced at the pixel level. Secondly, the resulting feature images are fused at the feature level and the fused feature images are segmented using superpixels. Lastly, a post-quake house damage index model is constructed. Results show an overall accuracy of 76.75%, 75.35% and 83.25% for three different types of imagery. This finding indicates that the proposed algorithm can be used to extract damage information from multisource remote sensing data and provide useful guidance for post-disaster rescue and assessment based on regional house damage conditions.

The Use Of Seismic Energy And Damage Index For Assesment Seismic Performance Of Building Under Seismic Excitation

Seismic input energy is transmitted into building consists of the kinetic energy, elastic strain energy, damping energy, and hysteretic energy. The amount of the input energy induced by earthquake transmitted into a building depends on earthquake characteristics and building dynamic properties. In this context, the hysteretic energy directly associated with damage to structural members through a parameter which known as the damage index were introduced. For this purposes, influence of earthquake characteristic on energy spectra for SDOF system were described and presented. In addition, influence of structural dynamic properties are also described and discussed. Next, to assess the damage potential to a building under seismic excitation, four story steel moment resisting frame were investigated under three selected ground motion records matching to the response spectra design the new Indonesian code. Furthermore, nonlinear dynamic time history analysis were performed using ABAQUS to obtain responses parameters in term of base shear, drift, input and hysteretic energy. Finally, the seismic performance of the building based on Park and Ang damage index model is presented and summarized.

RETRACTED ARTICLE: Estimation of Load-Induced Damage and Repair Cost in Post-Tensioned Concrete Rocking Walls

Post-tensioned concrete rocking walls might be used to avoid severe seismic damage at the base of structural walls, decrease residual drift, and lessen post-earthquake repair costs. The prediction of load-induced damage to the rocking wall resulting from seismic loading can provide an extremely valuable tool to evaluate the status and safety of structural concrete walls following earthquakes. In this study, the behavior and the damage state of monolithic, self-centering, rocking walls, as a new type of concrete rocking wall, are investigated. The nonlinear mechanical behavior of the wall is first modeled numerically, and subsequently the mechanical parameters from the numerical simulation are used to generate the local damage index. The results from the damage index model are compared with the full-scale test results, confirming the viability of the numerically based damage index method for estimating the seismically induced damage in concrete walls. Moreover, the estimated damage can be utilized as a qualitative and quantitative scale to assess the status of the wall following seismic loading events. Finally, an equation is proposed to estimate the repair cost based on the predicted damage state for the studied structural system.

Bayesian inferences of damage index and damage growth model based on on-site measurement data of steam turbine

Accurate prediction of remaining useful life (RUL) of plant turbine is a major scientific challenge for effective operation and maintenance in the power plant industry. This paper proposes an RUL prediction methodology that incorporates a damage index into the damage growth model. Bayesian inference technique is used to estimate the probability distribution of a damage index from on-site hardness measurements with uncertainties. A Bayesian approach to the damage growth model is proposed for aged steam turbines and the predictive distribution of the damage index is estimated using its mean and standard deviation. As a case study, real steam turbines in power plants were used to demonstrate the effectiveness of the proposed Bayesian approach. The results from the proposed damage growth model can be used to predict the RULs of the steam turbines of power plants regardless of load types (peak-load or base-load) of the power plant.

Prediction of top-of-rail friction control effects on rail RCF suppressed by wear

Rolling contact fatigue (RCF) and wear, two major deterioration processes, limit the lifetime of rails. These deterioration processes are even more severe on the curves of tracks used by heavy haul trains. Because wear is a material removing process, it can suppress the formation of RCF (also known as surface initiated cracks). In railways, cracks have a higher risk of instigating a catastrophic failure than wear; hence, it is comparatively better to have wear than to have cracks. By controlling the top-of-rail friction, both of these deteriorating processes can be reduced to enhance the lifetime of rails. In order to achieve these possible advantages, the infrastructure manager of the Swedish railway is planning to implement a top-of-rail friction control technology on the iron ore line in northern Sweden wherein RCF is a major problem on the curves. The present study uses a damage index model in a multi-body simulation software and predicts the probability of RCF formation with suppressing effect of wear for different friction control values. The effect of friction control is simulated on curve radii ranging from 200 to 3000m and axle loads ranging from 30 to 40t at a constant train speed of 60km/h. Findings show that on a very sharp circular curve, radius<300m, RCF can be eliminated without friction control due to the high wear rate. On moderate curves, 300<radius<1000m, a friction coefficient (µ) of, at most, 0.3 with a Kalker's coefficient of, at most, 30% is required to avoid RCF.

Performance level thresholds and damage evaluation for composite partially-restrained steel frame–reinforced concrete infill walls with concealed vertical slits

The method to determine the performance level thresholds of partially-restrained steel frame–reinforced concrete infill walls (PSRCW) with concealed vertical slits was presented within the framework of the performance based seismic design. Inter-story drift ratio is selected as a parameter to establish these thresholds based on the relationship between damage state and structural performance level. The damage analysis on the previous test results of PSRCW with concealed vertical slits is statistically investigated to quantify the performance level thresholds using the modified Park–Ang damage index model. The story damage state of a 5-story PSRCW with concealed vertical slits was also examined through nonlinear time history analysis. The maximum average inter-story drift ratio and damage index for this 5-story PSRCW with concealed vertical slits subjected to ten near-fault earthquake waves with velocity pulse were compared with the results from ten far-fault earthquake waves. For frequent and occasional earthquake hazard level, the velocity pulses of near-fault earthquake waves produce the similar damage upon PSRCW with concealed vertical slits in comparison with far-fault earthquake waves. However, for rare earthquake hazard level, the near-fault earthquake waves with velocity pulse cause more severe damage and larger inter-story drift ratio upon PSRCW with concealed vertical slits than the far-fault earthquake waves.

Analyzing the Effect of International Standards Details of Reinforced Concrete Buildings on Ductility and Energy Absorption of Structure (A Case Study of Nakhjavan Palace Project)

As studies have been conducted on structures exposed to earthquake or other similar destructive events revealed, implementation problems during construction have led to slight, serious and irrevocable damage. Meanwhile, with respect to various sensitive and subtle details, implementing concrete structures have not been excluded from this principle or are involved with these problem’s consequences. The present study investigated the relation between ductility and energy absorption, especially when the imposed lateral load is alternative. Also, the issue of energy-taking and input energy dissipation in a structure implemented according to international standards details of reinforced was studied. Furthermore, by implementing damage index model based on hysteric energy theory, three index levels including elemental, stratified and general structure damage were presented and the importance of precisely implementing regulation details were interpreted. Moreover, ductility and energy absorption level in tall structures’ load revisiting systems as well as structures’ non-linear behavior causes were explained. Since this case study focused on bending frame system and shear wall and analyzed total deformation of structures constituting shear wall and rigid frame. The research findings can be useful to determine the effect of implementing international standards details of reinforced concrete buildings on ductility and energy absorption of structure.

Monitoring fatigue-induced transverse matrix cracks in laminated composites using built-in acousto-ultrasonic techniques

This work investigated the use of ultrasonic wave propagation in a composite laminate to monitor transverse matrix cracking. It was found that the change in the signal’s power spectral density correlates to crack density increase, and its sensitivity was dependent on the actuator to sensor orientation. This orientation dependence was found to be the same as that of the laminate’s stiffness degradation. A crack density damage index model was developed that relates signal changes to laminate stiffness degradation due to transverse matrix cracks. With this damage index model, a matrix cracking monitoring system was proposed, implemented, and validated. The developed system requires a calibration test for the composite layup of interest and a minimum of one actuator and two sensors at different angle orientations. The calibration test and general approach steps are described and validated. The system’s crack density estimates match experimentally measured crack density values within established error bounds.

Implementation of the damage index approach for the rapid evaluation of earthquake resistant buildings

This paper presents a promising approach to modeling the building resistance in the seismic rehabilitation process. The damage index model (DIM) can be interactively utilized into the Geographical Information Systems (GIS) in order to compute parameters and to analyze data for a quality management purpose. It can perform an easy accessibility of the data to evaluate buildings for earthquake mitigation and preparedness. This research article intended to introduce a software program by using an integration system to design and to dissect the data for evaluating a building resistance against earthquakes. This paper promises a new integrated system for rapid evaluation of buildings, further a city planning by combination of GIS, civil engineering and industrial engineering upon the Federal Emergency Management Agency (FEMA) accompanied by seismic data, structure, parcel, material type, foundation, ceiling, wall, floor, the interior and the exterior. This software has been programmed based on the Damage Index (DI) algorithm that was developed by Pirasteh et al. (Int J Geoinformatics 5(4): 34–41, 2009). Later, based on the proposed algorithm or model the essential parameters have been adopted in Matrix laboratory (MATLAB) environment to yield a new software program for the meliorating earthquake mitigation and preparedness processes. This software program can identify vulnerability of the buildings ranking from 1 to 100. In addition, this paper recommends establishing a scientific procedure in determining the vulnerability of the buildings for earthquake preparedness within a GIS environment. However, this software program can amend in detecting weak structures for rehabilitation.

Degradation and damage behaviors of steel frame welded connections

In order to study the degradation and damage behaviors of steel frame welded connections, two series of tests in references with different connection constructions were carried out subjected to various cyclic loading patterns. Hysteretic curves, degradation and damage behaviours and fatigue properties of specimens were firstly studied. Typical failure modes and probable damage reasons were discussed. Then, various damage index models with variables of dissipative energy, cumulative displacement and combined energy and displacement were summarized and applied for all experimental specimens. The damage developing curves of ten damage index models for each connection were obtained. Finally, the predicted and evaluated capacities of damage index models were compared in order to describe the degraded performance and failure modes. The characteristics of each damage index model were discussed in depth, and then their distributive laws were summarized. The tests and analysis results showed that the loading histories significantly affected the distributive shapes of damage index models. Different models had their own ranges of application. The selected parameters of damage index models had great effect on the developing trends of damage curves. The model with only displacement variable was recommended because of a more simple form and no integral calculation, which was easier to be formulated and embedded in application programs.