scholarly journals Evaluation of dynamic behaviour of an experimentally tested model on a shaking table

2021 ◽  
Vol 1209 (1) ◽  
pp. 012053
Author(s):  
D Taušan ◽  
A Brandis ◽  
I Kraus
Keyword(s):  
Structural Analysis ◽  
Structural Damage ◽  
Dynamic Behaviour ◽  
Numerical Models ◽  
Soft Soil ◽  
Computer Software ◽  
Shallow Foundations ◽  
Shaking Table ◽  
River Sand ◽  
Foundation Soil

Abstract The usual structural analysis assumes that buildings are fixed to the ground. This is not always the case, especially for structures with shallow foundations on soft soils. It was learned from the literature review that neglecting soil compliance in the structural analysis may result in significant structural damage during an earthquake event. The seismic performance can greatly differ between buildings rigidly fixed to the ground and buildings for which soil compliance is considered. Therefore, the main goal of the experiment conducted in the laboratory of the Faculty of Civil Engineering in Rijeka was to observe the dynamic behaviour of a structure on soft soil. The model was experimentally tested using a shaking table. The foundation soil was modelled using local river sand. For parametric analysis, a numerical model was done using the computer software SAP2000. The model was calibrated using experimentally obtained results. A comparison between the experimental and numerical models is presented in the paper.

Experimental Identification of Structural Damage by Neural Networks

1995 ◽  
Author(s):  
Rosario Ceravolo ◽  
Alessandro De Stefano ◽  
Michel Grosjacques ◽  
Donato Sabia
Keyword(s):  
Neural Networks ◽  
Dynamic Response ◽  
Structural Damage ◽  
Dynamic Behaviour ◽  
Damage Identification ◽  
Numerical Models ◽  
Analysis Data ◽  
Simply Supported ◽  
Response Data ◽  
Experimental Identification

Abstract The problems involved in structural damage identification by means of pattern recognition neural techniques are addressed. As is known, mechanical system recognition can be achieved by making appropriate use of these connectionistic instruments. Recognition takes place on the basis of an incomplete set of data contained in the system’s dynamic response. Some methods, previously developed by the authors on the basis of numerical models, are validated through the use of noisy data. To this end, an experimental research was carried out on simply supported beams. The tests made it possible to acquire a wealth of dynamic response data from beams damaged artificially to produce defects of varying entity and position. The data obtained, appropriately normalised, are used as inputs for supervised neural networks. In particular, frequency analysis data are able to provide a summary characterisation of the distortion in a structure’s dynamic behaviour. Different signal processing and analysis procedures are compared in order to identify the best resolution and sensitivity capabilities in the diagnostic performance of neural networks.

scholarly journals Application of Artificial Neural Networks for Predicting the Bearing Capacity of Shallow Foundations on Rock Masses

2021 ◽  
Author(s):  
M. A. Millán ◽  
R. Galindo ◽  
A. Alencar
Keyword(s):  
Bearing Capacity ◽  
Analytical Solutions ◽  
Shear Failure ◽  
Numerical Models ◽  
Computational Effort ◽  
Shallow Foundations ◽  
Geological Strength Index ◽  
Rock Masses ◽  
Ann Model ◽  
Artificial Neural

AbstractCalculation of the bearing capacity of shallow foundations on rock masses is usually addressed either using empirical equations, analytical solutions, or numerical models. While the empirical laws are limited to the particular conditions and local geology of the data and the application of analytical solutions is complex and limited by its simplified assumptions, numerical models offer a reliable solution for the task but require more computational effort. This research presents an artificial neural network (ANN) solution to predict the bearing capacity due to general shear failure more simply and straightforwardly, obtained from FLAC numerical calculations based on the Hoek and Brown criterion, reproducing more realistic configurations than those offered by empirical or analytical solutions. The inputs included in the proposed ANN are rock type, uniaxial compressive strength, geological strength index, foundation width, dilatancy, bidimensional or axisymmetric problem, the roughness of the foundation-rock contact, and consideration or not of the self-weight of the rock mass. The predictions from the ANN model are in very good agreement with the numerical results, proving that it can be successfully employed to provide a very accurate assessment of the bearing capacity in a simpler and more accessible way than the existing methods.

Earthquake Damage Assessment Based on Fuzzy Logic and Neural Networks

2001 ◽  
Vol 17 (1) ◽  
pp. 89-112 ◽  
Author(s):  
Mauricio Sánchez-Silva ◽  
Libardo García
Keyword(s):  
Neural Networks ◽  
Fuzzy Logic ◽  
Damage Assessment ◽  
Structural Damage ◽  
Management Strategies ◽  
Computer Software ◽  
Good Representation ◽  
Feed Forward Neural Network ◽  
Risk Management Strategies ◽  
Potential Damage

Potential damage assessment is fundamental for defining mitigation procedures and risk management strategies. Damage assessment involves the difficulties of defining, assessing, and modeling the variables involved, as well as handling uncertainty. Seismic damage estimation of structures does not only depend on the behavior of the structural system, but it involves other factors, which differ in nature. The paper presents a methodology for damage assessment of structures that combines systems theory, fuzzy logic, and neural networks. A feed-forward neural network supported on the systemic organization of information is used to assess the expected structural damage for a given earthquake. The methodology provides a very useful environment to consider the context of the building structure. The network has been trained using the damage observed in the recent earthquake that occurred in central Colombia. Several sets of structures were evaluated and the results compared to the damage observed. The model showed to be highly reliable and a good representation of experts' opinions. Computer software ERS-99 was developed and is currently being used for teaching and consulting purposes.

Hysteresis Loops of Base Isolation System - An Overview

2021 ◽  
Vol 879 ◽  
pp. 189-201
Author(s):  
M.A. Amir ◽  
N.H. Hamid
Keyword(s):  
Earthquake Engineering ◽  
Structural Damage ◽  
Base Isolation ◽  
Numerical Models ◽  
Hysteresis Loops ◽  
Human Beings ◽  
Rc Buildings ◽  
Isolation System ◽  
Base Isolation System ◽  
Isolation Systems

Recently, there are a lot of technological developments in the earthquake engineering field to reduce structural damage and one of them is a base isolation system. The base isolation system is one of the best technologies for the safety of human beings and properties under earthquake excitations. The aim of this paper is to review previous research works on simulation of base isolation systems for RC buildings and their efficiency in the safety of these buildings. Base isolation decouples superstructure from substructure to avoid transmission of seismic energy to the superstructure of RC buildings. The most effective way to assess the base isolation system for RC building under different earthquake excitations is by conducting experiment work that consumes more time and money. Many researchers had studied the behavior of base isolation system for structure through modeling the behavior of the base isolation in which base isolator is modeled through numerical models and validated through experimental works. Previous researches on the modeling of base isolation systems of structures had shown similar outcomes as the experimental work. These studies indicate that base isolation is an effective technology in immunization of structures against earthquakes.

scholarly journals Thermal-Structural Design of Actively-Cooled Panels Reinforced by Light-Weight Truss Cores

2013 ◽  
Author(s):  
Hongwei Song ◽  
Mingjun Li ◽  
Chenguang Huang ◽  
Xi Wang
Keyword(s):  
Heat Transfer ◽  
Structural Analysis ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Thermal Environment ◽  
Numerical Models ◽  
Lightweight Design ◽  
Optimization Procedure ◽  
Combustion Gas ◽  
Design Variables

This paper focuses on thermal-structural analysis and lightweight design of actively-cooled panels reinforced by low density lattice-framed material (LFM) truss cores. Numerical models for actively-cooled panels are built up with parametric codes to perform the coupled thermal-structural analysis, considering the internal thermal environment of convective heat transfer in the combustor and convective heat transfer in the cooling channel, and internal pressures from the combustion gas and the coolant. A preliminary comparison of the LFM truss reinforced actively-cooled panel and the non-reinforced panel demonstrates that the thermal-structural behavior is significantly improved. Then, an optimization procedure is carried out to find the lightest design while satisfying thermal deformation and plastic strain constraints, with thicknesses of face sheets and topology parameters of LFM truss as design variables. The optimization result demonstrates that, compared with the non-reinforced actively-cooled panels, weight reduction for the panel reinforced by LFM truss may reach 19.6%. We have also fabricated this type of actively-cooled panel in the laboratory level, and the specimen shows good mechanical behaviors.

Application and Validation of Practical Tools for Nonlinear Soil-Foundation Interaction Analysis

2010 ◽  
Vol 26 (1) ◽  
pp. 111-129 ◽  
Author(s):  
Sivapalan Gajan ◽  
Prishati Raychowdhury ◽  
Tara C. Hutchinson ◽  
Bruce L. Kutter ◽  
Jonathan P. Stewart
Keyword(s):  
Interaction Analysis ◽  
Model Performance ◽  
Shallow Foundations ◽  
Winkler Foundation ◽  
Gap Formation ◽  
Foundation Soil ◽  
Lateral Connection ◽  
Practical Guidelines ◽  
Soil Foundation ◽  
The Moment

Practical guidelines for characterization of soil-structure interaction (SSI) effects for shallow foundations are typically based on representing foundation-soil interaction in terms of viscoelastic impedance functions that describe stiffness and damping characteristics. Relatively advanced tools can describe nonlinear soil-foundation behavior, including temporary gap formation, foundation settlement and sliding, and hysteretic energy dissipation. We review two tools that describe such effects for shallow foundations and that are implemented in the computational platform OpenSees: a beam-on-nonlinear-Winkler foundation (BNWF) model and a contact interface model (CIM). We review input parameters and recommend parameter selection protocols. Model performance with the recommended protocols is evaluated through model-to-model comparisons for a hypothetical shear wall building resting on clay and model-data comparisons for several centrifuge test specimens on sand. The models describe generally consistent moment-rotation behavior, although shear-sliding and settlement behaviors deviate depending on the degree of foundation uplift. Pronounced uplift couples the moment and shear responses, often resulting in significant shear sliding and settlements. Such effects can be mitigated through the lateral connection of foundation elements with tie beams.

scholarly journals Normal modes of a "cylindrical valley" of alluvium

1989 ◽  
Vol 22 (2) ◽  
pp. 76-80 ◽  
Author(s):  
W. R. Stephenson
Keyword(s):  
Shear Modulus ◽  
Structural Damage ◽  
Travelling Waves ◽  
Soft Soil ◽  
Normal Modes ◽  
Modes Of Vibration ◽  
Rigid Material ◽  
Cylindrical Volume ◽  
High Bulk ◽  
Low Shear

Some normal modes of vibration are deduced for a cylindrical volume of high bulk modulus, low shear modulus material, embedded in an infinite half space of rigid material. The manner in which they may be excited by travelling waves in the rigid material is examined. The relevance of such processes is discussed with regard to the enhancement of structural damage on soft soil during an earthquake.

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