scholarly journals Proposal of Damage Index Ratio for Low- to Mid-Rise Reinforced Concrete Moment-Resisting Frame with Setback Subjected to Uniaxial Seismic Loading

2021 ◽  
Vol 11 (15) ◽  
pp. 6754
Author(s):  
Taufiq Ilham Maulana ◽  
Badamkhand Enkhtengis ◽  
Taiki Saito
Keyword(s):  
Reinforced Concrete ◽  
Experimental Test ◽  
Structural Damage ◽  
Ground Motions ◽  
Frame Analysis ◽  
Damage Index ◽  
Experimental Tests ◽  
Test Results ◽  
Earthquake Ground Motions ◽  
Index Ratio

A vertical irregularity setback in reinforced concrete (RC) building affects its performance and response especially subjected to earthquake ground motions. It is necessary to understand how the seismic damage is established due to setbacks and avoid damage concentration on the irregularity section. The objective of this study is to propose a formula to estimate the damage distribution along the height of the setback building from a geometric measure of the degree of irregularity. First, previous experimental tests for two types of setback buildings, a towered and a stepped setback frames, were analyzed to verify the accuracy of the frame analysis. The results of the frame analysis considerably matched the experimental test results. Furthermore, to study the relationship between the degree of setback and the distribution of damage, a parametric study was conducted using 35 reinforced concrete setback frames, consisting of models with stepped setback type and towered setback type with different degrees of setback. The inelastic dynamic analyses of all the frames under three earthquake ground motions were conducted. The irregularity indices proposed in literature were adopted to express the degree of setback and the structural damage was expressed by the Park–Ang damage index. Using nonlinear regression analysis, formulas to estimate damage index ratio between two main structure parts (tower and base) from setback indices were proposed. Finally, the proposed formula was applied to the experimental test results to confirm its validity.

On axial compressive behavior of steel fiber reinforced concrete confined by FRP

2021 ◽  
pp. 136943322098165
Author(s):  
Hossein Saberi ◽  
Farzad Hatami ◽  
Alireza Rahai
Keyword(s):  
Reinforced Concrete ◽  
Experimental Test ◽  
Steel Fiber ◽  
Experimental Tests ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Test Results ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Frp Confinement

In this study, the co-effects of steel fibers and FRP confinement on the concrete behavior under the axial compression load are investigated. Thus, the experimental tests were conducted on 18 steel fiber-reinforced concrete (SFRC) specimens confined by FRP. Moreover, 24 existing experimental test results of FRP-confined specimens tested under axial compression are gathered to compile a reliable database for developing a mathematical model. In the conducted experimental tests, the concrete strength was varied as 26 MPa and 32.5 MPa and the steel fiber content was varied as 0.0%, 1.5%, and 3%. The specimens were confined with one and two layers of glass fiber reinforced polymer (GFRP) sheet. The experimental test results show that simultaneously using the steel fibers and FRP confinement in concrete not only significantly increases the peak strength and ultimate strain of concrete but also solves the issue of sudden failure in the FRP-confined concrete. The simulations confirm that the results of the proposed model are in good agreement with those of experimental tests.

scholarly journals Hysteretic Behavior of Steel Reinforced Concrete Columns Based on Damage Analysis

2019 ◽  
Vol 9 (4) ◽  
pp. 687 ◽  
Author(s):  
Bin Wang ◽  
Guang Huo ◽  
Yongfeng Sun ◽  
Shansuo Zheng
Keyword(s):  
Reinforced Concrete ◽  
Damage Index ◽  
Hysteresis Loops ◽  
Time History ◽  
Hysteretic Behavior ◽  
Loading Path ◽  
Test Results ◽  
Hysteresis Model ◽  
Skeleton Curve ◽  
Steel Reinforced Concrete

With the aim to model the seismic behavior of steel reinforced concrete (SRC) frame columns, in this research, hysteresis and skeleton curves were obtained based on the damage test results of SRC frame columns under low cyclic repeat loading and the hysteretic behavior of the frame columns was further analyzed. Then, the skeleton curve and hysteresis loops were further simplified. The simplified skeleton curve model was obtained through the corresponding feature points obtained by mechanical and regression analysis. The nonlinear combination seismic damage index, which was developed by the test results and can well reflect the effect of the loading path and the number of loading cycle of SRC frame columns, was used to establish the cyclic degradation index. The strength and stiffness degradation rule of the SRC frame columns was analyzed further by considering the effect of the accumulated damage caused by an earthquake. Finally, the hysteresis model of the SRC frame columns was established, and the specific hysteresis rules were given. The validity of the developed hysteresis model was verified by e comparison between the calculated results and the test results. The results showed that the model could describe the hysteresis characteristics of the SRC frame columns under cyclic loading and provide guidance for the elastoplastic time-history analysis of these structures.

Structural Health Monitoring Experimental System Implemented in a Turboprop Commercial Aircraft

2007 ◽  
Vol 347 ◽  
pp. 311-317
Author(s):  
Igor Bovio ◽  
Leonardo Lecce
Keyword(s):  
Structural Damage ◽  
Damage Index ◽  
Experimental System ◽  
Experimental Tests ◽  
Processing Technique ◽  
Commercial Aircraft ◽  
Destructive Testing ◽  
Before And After ◽  
Neural Network Algorithm ◽  
Testing Field

The purpose of the paper is to present an innovative application within the Non Destructive Testing field based upon vibration measurements developed by the authors, and already tested for analysing damage of many structural elements. After having tested this application on different test articles in laboratory condition, experimental tests have been executed, in collaboration with the ATR company, on a turboprop ATR-72 aircraft, in order to validate the technique on a real aeronautical structure. The monitoring system have operated an off-line check on the structure, during the aircraft ground operations, as if it were a normal maintenance procedure. The results are reported in the paper. This proposed new method is based upon the acquisition and comparison of the Frequency Response Functions (FRFs) of the monitored structure before and after damage occurs. Structural damage modify the dynamic behaviour of a structure affecting its mass, stiffness and damping, and consequently the FRFs of a damaged structure, when compared with the FRFs of its sound configuration, making the identification, localization and quantification of damage possible. The activities presented in the paper focus mainly on a new FRFs processing technique based upon the determination of a representative “Damage Index” for identifying and analysing damage. Furthermore, a dedicated neural network algorithm has been elaborated to develop an automatic system which recognises positive samples, “healthy” states of the analysed structure, discarding negative ones, “damaged or perturbed” states of the analysed structure. From an architectural standpoint, piezoceramic patches have been used as both actuators and sensors.

scholarly journals Punching shear behavior of thick reinforced concrete slabs according to Strut-and-Tie model

2014 ◽  
Vol 13 (3) ◽  
pp. 183-192
Author(s):  
Tadeusz Urban ◽  
Jakub Krakowski
Keyword(s):  
Reinforced Concrete ◽  
Experimental Test ◽  
Shear Behavior ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Test Results ◽  
Strut And Tie ◽  
Reinforced Concrete Slabs ◽  
Symmetric Loading ◽  
Strut And Tie Model

The punching shear behavior of thick reinforced concrete slabs was analyzed in this paper by using strut-and-tie model (S-T). Calculating procedures were compared to our own experimental test results. The analyzed elements were subjected to symmetric loading and without shear reinforcement.

Selection of the Test Specimens for Seismic Tests of Air-Operated Valve Actuators for Nuclear Power Plants

2019 ◽  
Author(s):  
Nobuo Kojima ◽  
Yoshitaka Tsutsumi ◽  
Yoshinao Matsubara ◽  
Koji Nishino ◽  
Yasuyuki Ito ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Ground Motions ◽  
Test Results ◽  
Earthquake Ground Motions ◽  
Dynamic Function ◽  
Design Earthquake ◽  
Seismic Tests ◽  
Selection Of

Abstract The soundness for the function of air-operated valves in nuclear power plants during earthquake has been investigated via seismic test results and so forth. Since the seismic response acceleration has increased more and more with a recent reassessment of design earthquake ground motions conducted according to the revised Japanese nuclear safety regulation, it is necessary to evaluate the soundness for the function of various valves subject to large acceleration beyond design basis. The air-operated valves currently installed in the nuclear power plants in Japan play the important roles in the sever accident events. In this study, we classified them based on the valve type, manufactures and the previous test results. Furthermore, we proposed the strategy for evaluating the seismic-proof and the seismic test condition for examining the soundness of the dynamic function. Here, the dynamic function is defined as the function required under and after earthquakes.

Probabilistic Seismic Capacity Models for RC Bridge Columns

2013 ◽  
Vol 353-356 ◽  
pp. 2028-2032
Author(s):  
Wei Dong Zhuo ◽  
Wu Hua Zeng
Keyword(s):  
Reinforced Concrete ◽  
Damage Model ◽  
Damage Index ◽  
Concrete Columns ◽  
Bridge Columns ◽  
Test Results ◽  
Seismic Capacity ◽  
Modified Model ◽  
Performance Levels ◽  
Rc Bridge Columns

Reinforced concrete (RC) columns are the vital members in bridge under the action of earthquake. In this paper, a modified Park-Ang damage model with nonlinear combination of the deformation and the hysteretic energy is proposed as a measure of RC bridge columns damage. The nonlinear combination coefficient of the modified model has been calculated based on the 151 cyclic test results of flexure dominant reinforced concrete columns. In additional, the correlation between performance levels and the values of damage index is presented. It is suggested that the scatter of the modified model at different performance levels is significantly reduced compared to the original Park-Ang damage model. At last, the probabilistic capacity models for RC bridge columns are applied to perform a damage analysis.

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