Performance of a Post-Byzantine Triple-Domed Basilica under Near and Far Fault Seismic Loads

2015 ◽  
pp. 831-867 ◽  
Author(s):  
Constantine C. Spyrakos ◽  
Charilaos A. Maniatakis ◽  
Panagiotis Kiriakopoulos ◽  
Alessio Francioso ◽  
Ioannis M. Taflampas
Keyword(s):  
Structural Damage ◽  
New Technology ◽  
Element Model ◽  
Seismic Loads ◽  
Regional Seismicity ◽  
Near Fault ◽  
Collapse Mechanisms ◽  
Before And After ◽  
Out Of Plane ◽  
Structural Parts

In this Chapter a triple-domed basilica constructed at the end of the 19th century is selected as a case study to present a methodology for the selection of the appropriate intervention techniques in monumental structures. The methodology includes in-situ and laboratory testing, application of analytical methods, consideration of geotechnical parameters and regional seismicity. Seismic loads are estimated according to contemporary and older concepts for seismic design. Since the impact of near-fault phenomena on masonry structures has not been thoroughly studied, although considered as responsible for extensive structural damage during major seismic events, a procedure is presented in order to account for the special characteristics of strong ground motion, in the so-called near-fault region. The seismic performance of the structure before and after interventions, using traditional and new technology, is assessed by applying a validated finite element model. Also, the out-of-plane behavior of structural parts is evaluated through kinematic analysis of selective collapse mechanisms.

Damage Identification of Multi-Box Steel-Concrete Composite Bridges Based on Modal Curvature Difference Method

2012 ◽  
Vol 226-228 ◽  
pp. 1689-1692 ◽  
Author(s):  
Yi Qiang Xiang ◽  
Li Si Liu ◽  
Yu Liang He
Keyword(s):  
Difference Method ◽  
Structural Damage ◽  
Damage Identification ◽  
Damage Index ◽  
Element Model ◽  
Before And After ◽  
Composite Bridges ◽  
Modal Curvature ◽  
Composite Bridge ◽  
The Difference

Based on the data from dynamic analysis of a 40m-span multi-box steel-concrete composite bridge and the difference value of its modal curvature before and after the structural damage, this paper detects the damage locations in steel-concrete composite bridge by modal curvature difference method (MCDM). Here we adopt the updated finite element model in last work as analytical model, taking concrete density and elastic modulus as updating parameters and modal frequency+MAC as reference data. The results indicate that the modal curvature difference method can well locate the damages in steel-concrete composite bridge, especially the damage in concrete. But the change rate of frequency as damage index is insensitive to the bridge damage and the method can’t be applied solely for practical.

Performance of clay masonry veneer in wood-stud walls subjected to out-of-plane seismic loads

2010 ◽  
Vol 39 (14) ◽  
pp. 1585-1609 ◽  
Author(s):  
Hussein O. Okail ◽  
P. Benson Shing ◽  
Richard E. Klingner ◽  
William M. McGinley
Keyword(s):  
Seismic Loads ◽  
Out Of Plane

Character Analysis of Balance and Imbalance of Varying Rigidity of Rigid Pile Composite Foundation under Seismic Load

2014 ◽  
Vol 1065-1069 ◽  
pp. 19-22
Author(s):  
Zhen Feng Wang ◽  
Ke Sheng Ma
Keyword(s):  
Finite Element ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Element Model ◽  
Composite Foundation ◽  
Seismic Load ◽  
Seismic Loads ◽  
Element Analysis ◽  
Rigid Pile ◽  
Rigid Pile Composite Foundation

Based on ABAQUS finite element analysis software simulation, the finite element model for dynamic analysis of rigid pile composite foundation and superstructure interaction system is established, which selects the two kinds of models, by simulating the soil dynamic constitutive model, selecting appropriate artificial boundary.The influence of rigid pile composite foundation on balance and imbalance of varying rigidity is analyzed under seismic loads. The result shows that the maximum bending moment and the horizontal displacement of the long pile is much greater than that of the short pile under seismic loads, the long pile of bending moment is larger in the position of stiffness change. By constrast, under the same economic condition, the aseismic performance of of rigid pile composite foundation on balance of varying rigidity is better than that of rigid pile composite foundation on imbalance of varying rigidity.

Seismic Response Analysis of CFST Arch Bridge Considering Input Earthquake Characteristics

2011 ◽  
Vol 255-260 ◽  
pp. 962-966
Author(s):  
Fan Xing ◽  
Lin Zhao ◽  
Ya Zhe Xing
Keyword(s):  
Seismic Response ◽  
Research Result ◽  
Steel Tube ◽  
Response Analysis ◽  
Vibration Period ◽  
Arch Bridge ◽  
Near Fault ◽  
Long Span ◽  
Cfst Arch Bridge ◽  
Out Of Plane

In view of huge destructibility of the near-fault ground motions, structures with long natural vibration period are liable to fall into nonlinear reaction stage. Based on a full understanding of the near-fault seismic spectrum characteristics, the out-of-plane seismic response of a long span concrete-filled steel tube (CFST) arch bridge was studied in depth, and the research result could offer a reference for near-fault aseismic design.

FEM Free Damage Detection of Beam Structures Using the Deflections Estimated by Modal Flexibility Matrix

2021 ◽  
pp. 2150128
Author(s):  
Wen-Yu He ◽  
Wei-Xin Ren ◽  
Lei Cao ◽  
Quan Wang
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Damage Index ◽  
Element Model ◽  
Mode Shapes ◽  
Beam Structures ◽  
Flexibility Matrix ◽  
Damage Quantification ◽  
Modal Flexibility ◽  
The Cost

The deflection of the beam estimated from modal flexibility matrix (MFM) indirectly is used in structural damage detection due to the fact that deflection is less sensitive to experimental noise than the element in MFM. However, the requirement for mass-normalized mode shapes (MMSs) with a high spatial resolution and the difficulty in damage quantification restricts the practicability of MFM-based deflection damage detection. A damage detection method using the deflections estimated from MFM is proposed for beam structures. The MMSs of beams are identified by using a parked vehicle. The MFM is then formulated to estimate the positive-bending-inspection-load (PBIL) caused deflection. The change of deflection curvature (CDC) is defined as a damage index to localize damage. The relationship between the damage severity and the deflection curvatures is further investigated and a damage quantification approach is proposed accordingly. Numerical and experimental examples indicated that the presented approach can detect damages with adequate accuracy at the cost of limited number of sensors. No finite element model (FEM) is required during the whole detection process.

Comparative nonlinear seismic analysis of an existing RC bridge designed with obsolete codes

2022 ◽  
pp. 136943322210747
Author(s):  
Germán Nanclares ◽  
Daniel Ambrosini ◽  
Oscar Curadelli
Keyword(s):  
Numerical Model ◽  
Seismic Design ◽  
Seismic Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Highway Bridges ◽  
Element Model ◽  
Cyclic Behavior ◽  
Transverse Reinforcement ◽  
3D Finite Element ◽  
Collapse Mechanisms

The evolution of seismic design and calculation criteria for highway bridges has a direct influence on their structural behavior. This paper presents a nonlinear dynamic analysis using a detailed 3D finite element model of an existing bridge, with different design criteria for the column transverse reinforcement, according to code requirements of different times. The numerical model is able to simulate both the collapse of the structure and the generation of damage in its elements when subjected to extreme seismic actions. Through the numerical model, it is possible to represent the cyclic behavior of the concrete, and to evaluate the influence of the transverse reinforcement assigned to the column on the overall response of the bridge. The formation of plastic hinges is verified, as well as the identification of different collapse mechanisms.

Experimentally Validated Computational Simulation of Lumbar Spine Intervertebral Disc Puncture

2011 ◽  
Author(s):  
Kristen E. Lipscomb ◽  
Nesrin Sarigul-Klijn
Keyword(s):  
Back Pain ◽  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Nucleus Pulposus ◽  
Chronic Back Pain ◽  
Medical Condition ◽  
Computational Simulation ◽  
Element Model ◽  
Before And After ◽  
Spine Model

Back pain is a debilitating medical condition, often with an unclear source. Over time, back pain can affect the work and lifestyle of an individual by reducing job productivity and time spent on enjoyable activities. Discography of the intervertebral disc (IVD) is often used to diagnose pathology of the disc and determine if it may be a source for chronic back pain. It has recently been suggested that discography may lead to IVD degeneration, and has been a cause of controversy among spine care physicians. Using the results from a cadaveric experimental model, a finite element model was first validated. Then, a study was conducted to better understand the changes caused by discography on human spine mechanics. An anatomically accurate L3-L5 lumbar spine model was developed using computed tomography scans. Discography was simulated in the model as an area in the disc affected by needle puncture. The material properties in the nucleus pulposus were adjusted to match experimental data both before and after puncture. The results show that puncture of the IVD leads to increased deformation as well as increased stresses in the disc. Pressure in the nucleus pulposus found to decrease after puncture, and was calculated in the course of this study. Puncturing the IVD changes disc mechanics and may lead to progressive spine issues in the future such as disc degeneration. While discography has been the gold standard to determine if the disc was a source of back pain in patients for many years, the potential long-term degenerative effects of the procedure are only now coming into light, and must be closely examined.

Using the Simplified 3D DIC Method to Measure the Deformation of 3D Surface

2011 ◽  
Vol 121-126 ◽  
pp. 3945-3949 ◽  
Author(s):  
Shih Heng Tung ◽  
Jui Chao Kuo ◽  
Ming Hsiang Shih ◽  
Wen Pei Sung
Keyword(s):  
Measurement Accuracy ◽  
Good Accuracy ◽  
Correlation Method ◽  
Image Correlation ◽  
2D Digital Image Correlation ◽  
Plate Specimen ◽  
Before And After ◽  
Out Of Plane ◽  
Plane Displacement ◽  
2D And 3D

In recent years, 2D digital image correlation method (DIC) has been widely used in the measurement of plane strain. However, out-of-plane displacement could be induced during the loading and it would affect the measurement accuracy. Thus, a 3D measurement is necessary. This study utilizes a simplified 3D DIC to measure the geometry of an object before and after deformation. Then the finite element concept is involved to determine the strain after deformation. A flat plate specimen with in-plane and out-of-plane displacement is observed. Both 2D and 3D DIC are used to analyze the strain. The results show that using 3D DIC to measure strain is feasible and with a very good accuracy.

Nonlinear Structural Damage Detection Based on Adaptive Volterra Filter Model

2018 ◽  
Vol 18 (02) ◽  
pp. 1871003 ◽  
Author(s):  
J. Prawin ◽  
A. Rama Mohan Rao
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Linear Models ◽  
Time History ◽  
Diagnostic Techniques ◽  
Filter Model ◽  
Volterra Filter ◽  
Damage Indices ◽  
Before And After ◽  
Nonlinear Time History

The majority of the existing damage diagnostic techniques are based on linear models. Changes in the state of the dynamics of these models, before and after damage in the structure based on the vibration measurements, are popularly used as damage indicators. However, the system may initially behave linearly and subsequently exhibit nonlinearity due to the incipience of damage. Breathing cracks that exhibit bilinear behavior are one such example of the damage induced due to nonlinearity. Further many real world structures even in their undamaged state are nonlinear. Hence, in this paper, we present a nonlinear damage detection technique based on the adaptive Volterra filter using the nonlinear time history response. Three damage indices based on the adaptive Volterra filter are proposed and their sensitiveness to damage and noise is assessed through two numerically simulated examples. Numerical investigations demonstrate the effectiveness of the adaptive Volterra filter model to detect damage in nonlinear structures even with measurement noise.

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