scholarly journals Integration of Modelling Approaches for the Seismic Assessment of Complex URM Buildings: The Podestà Palace in Mantua, Italy

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 269
Author(s):  
Sergio Lagomarsino ◽  
Stefania Degli Abbati ◽  
Daria Ottonelli ◽  
Serena Cattari
Keyword(s):  
Global Analysis ◽  
Integrated Approach ◽  
Element Model ◽  
Computational Effort ◽  
Seismic Assessment ◽  
Structural Element ◽  
Seismic Behaviour ◽  
Dynamic Interactions ◽  
Equivalent Frame ◽  
Modelling Strategies

This study investigated seismic assessments of the Podestà Palace in Mantua (Italy). This masonry palace has a complex geometrical configuration that resulted from the addition of various units stratified over centuries. This feature makes seismic assessment challenging from a modelling perspective due to the interaction among units. Here, an integrated use of three modelling strategies characterised by a different computational effort and degree of accuracy was employed: (i) the Structural Element Model, according to the Equivalent Frame Approach, to study the global response of the whole structure and to estimate the mutual dynamic interactions among units; (ii) the Macro-Block Model, to assess the out-of-plane response of facades prone to the activation of local mechanisms; and (iii) the Finite Element Model, to deepen the seismic response of some critical parts, highlighted by a global analysis but also roughly described by the Equivalent Frame Model. This integrated approach consists in the use of results achieved from one modelling approach as input for another. For example, the floor spectra estimated by (i) were used to define the seismic input in (ii); for assessing the most critical portions, more accurate models were addressed (as in case (iii)). The comprehensive interpretation of the seismic behaviour obtained by these models also allowed us to address more rationally possible strengthening solutions, such as the in-plane stiffening of vaults (particularly spread in the building), aimed to guarantee a better redistribution of seismic actions in such a complex building.

scholarly journals Numerical Modelling of Reinforced Concrete Slender Walls Subjected to Coupled Axial Tension–Flexure

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiaowei Cheng ◽  
Haoyou Zhang
Keyword(s):  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Element Model ◽  
Lateral Loading ◽  
Design Parameters ◽  
Seismic Behaviour ◽  
High Rise ◽  
Ultimate Deformation ◽  
Axial Tension ◽  
Plastic Hinge Length

AbstractUnder strong earthquakes, reinforced concrete (RC) walls in high-rise buildings, particularly in wall piers that form part of a coupled or core wall system, may experience coupled axial tension–flexure loading. In this study, a detailed finite element model was developed in VecTor2 to provide an effective tool for the further investigation of the seismic behaviour of RC walls subjected to axial tension and cyclic lateral loading. The model was verified using experimental data from recent RC wall tests under axial tension and cyclic lateral loading, and results showed that the model can accurately capture the overall response of RC walls. Additional analyses were conducted using the developed model to investigate the effect of key design parameters on the peak strength, ultimate deformation capacity and plastic hinge length of RC walls under axial tension and cyclic lateral loading. On the basis of the analysis results, useful information were provided when designing or assessing the seismic behaviour of RC slender walls under coupled axial tension–flexure loading.

scholarly journals Low-rise structures in reinforced concrete: approximation of material nonlinearity for global stability analysis

2018 ◽  
Vol 11 (1) ◽  
pp. 1-25
Author(s):  
L. M. MOREIRA ◽  
C. H. MARTINS
Keyword(s):  
Global Stability ◽  
Iterative Process ◽  
Global Analysis ◽  
Second Order ◽  
Material Nonlinearity ◽  
Flexural Stiffness ◽  
Analysis Model ◽  
Structural Element ◽  
Global Stability Analysis ◽  
Stiffness Reduction

Abstract In the analysis of the second-order global effects, the material nonlinearity (NLF) can be considered in an approximate way, defining for the set of each structural element a mean flexural stiffness. However, there is less research concerning low-rise buildings in the analysis of global stability in contrast to high buildings, because these have a greater sensitivity to this phenomenon and they are more studied. In this way, the paper objective is to determine the flexural stiffness values, of beams and columns, for buildings with less than four floors, to approximate consideration of the NLF in the global analysis. The idealized examples to buildings with 1, 2 and 3 floors, being simulated through the software CAD/TQS and an analysis model based in an iterative process. The simulations results defined the stiffness values of the set of beams and columns in each example, followed by a statistical analysis to define general values of application in the buildings. Finally, a proposal is suggested of stiffness reduction coefficients for beams and columns to be adopted in the approximation the NLF (EIsec = αv/p ∙ Eci Ic), as follows: buildings with 1 floor (αv = 0,17 and αp = 0,66), buildings with 2 floors (αv = 0,15 and αv = 0,71) and buildings with 3 floors (αv = 0,14 and αv = 0,72). The results obtained can be used for the analysis of low-rise structures to consider the second order global effects with more safely.

scholarly journals Holistic versus monomeric strategies for hydrological modelling of modified hydrosystems

2010 ◽  
Vol 7 (5) ◽  
pp. 8265-8308
Author(s):  
I. Nalbantis ◽  
A. Efstratiadis ◽  
E. Rozos ◽  
M. Kopsiafti ◽  
D. Koutsoyiannis
Keyword(s):  
Water Management ◽  
Holistic Approach ◽  
Calibration Procedure ◽  
Computational Effort ◽  
Test Case ◽  
Bottom Up ◽  
Modelling Strategies ◽  
Extended Surface ◽  
Output Information ◽  
Surface And Groundwater

Abstract. The modelling of modified basins that are inadequately measured constitutes a challenge for hydrological science. Often, models for such systems are detailed and hydraulics-based for only one part of the system while for other parts oversimplified models or rough assumptions are used. This is typically a bottom-up approach, which seeks to exploit knowledge of hydrological processes at the micro-scale at some components of the system. Also, it is a monomeric approach in two ways: first, essential interactions among system components may be poorly represented or even omitted; second, differences in the level of detail of process representation can lead to uncontrolled errors. Additionally, the calibration procedure merely accounts for the reproduction of the observed responses using typical fitting criteria. The paper aims to raise some critical issues, regarding the entire modelling approach for such hydrosystems. For this, two alternative modelling strategies are examined that reflect two modelling approaches or philosophies: a dominant bottom-up approach, which is also monomeric and very often, based on output information and a top-down and holistic approach based on generalized information. Critical options are examined, which codify the differences between the two strategies: the representation of surface, groundwater and water management processes, the schematization and parameterization concepts and the parameter estimation methodology. The first strategy is based on stand-alone models for surface and groundwater processes and for water management, which are employed sequentially. For each model, a different (detailed or coarse) parameterization is used, which is dictated by the hydrosystem schematization. The second strategy involves model integration for all processes, parsimonious parameterization and hybrid manual-automatic parameter optimization based on multiple objectives. A test case is examined in a hydrosystem in Greece with high complexities, such as extended surface-groundwater interactions, ill-defined boundaries, sinks to the sea and anthropogenic intervention with unmeasured abstractions both from surface and groundwater. Criteria for comparison are the physical consistency of parameters, the reproduction of runoff hydrographs at multiple sites within the basin, the likelihood of uncontrolled model outputs, the required amount of computational effort and the performance within a stochastic simulation setting.

The effects of well damage and completion designs on geo-electrical responses in mature wellbore environments

Geophysics ◽  
2021 ◽  
pp. 1-50
Author(s):  
Gungor D. Beskardes ◽  
Chester J. Weiss ◽  
Evan Um ◽  
Michael Wilt ◽  
Kris MacLennan
Keyword(s):  
Finite Element ◽  
Electrical Potential ◽  
Real Life ◽  
Element Model ◽  
Computational Effort ◽  
Real Surface ◽  
Well Completion ◽  
Geologic Storage ◽  
Well Damage ◽  
Electrical Responses

Well integrity is one of the major concerns in long-term geologic storage sites due to its potential risk for well leakage and groundwater contamination. Evaluating changes in electrical responses due to energized steel-cased wells has the potential to quantify and predict possible wellbore failures as any kind of breakage or corrosion along highly-conductive well casings will have an impact on the distribution of subsurface electrical potential. However, realistic wellbore-geoelectrical models that can fully capture fine scale details of well completion design and state of well damage at the field scale require extensive computational effort or can even be intractable to simulate. To overcome this computational burden while still keeping the model realistic, we utilize the Hierarchical Finite Element Method which represents electrical conductivity at each dimensional component (1-D edges, 2-D planes and 3-D cells) of a tetrahedra mesh. This allows us to consider well completion designs with real-life geometric scales and well systems with realistic, detailed, progressive corrosion and damage in our models. Here, we present a comparison of possible discretization approaches of a multi-casing completion design in the finite element model. The impacts of the surface casing length and the coupling between concentric well casings, as well as the effects of the degree and the location of well damage on the electrical responses are also examined. Finally, we analyze real surface electric field data to detect the wellbore integrity failure associated with damage.

Seismic behaviour of prestressed high-strength concrete piles under combined axial compression and cyclic horizontal loads

2018 ◽  
Vol 22 (5) ◽  
pp. 1089-1105 ◽  
Author(s):  
Xizhi Zhang ◽  
Sixin Niu ◽  
Jia-Bao Yan ◽  
Shaohua Zhang
Keyword(s):  
Finite Element ◽  
Axial Compression ◽  
High Strength Concrete ◽  
High Strength ◽  
Element Model ◽  
Test Results ◽  
Seismic Behaviour ◽  
Strength Concrete ◽  
Concrete Piles ◽  
Concrete Pile

In order to simulate the seismic behaviour of the prestressed high-strength concrete piles under working state, six full-scale prestressed high-strength concrete piles were tested under combined axial compression and cyclic horizontal loads. Different axial compression levels and prestressing levels of prestressed tendons were studied in this test programme. The failure mode, bending resistance, displacement ductility, stiffness degradation and energy dissipation of the prestressed high-strength concrete piles under different loading scenarios were measured and analysed. Test results indicated that the axial compression ratio and prestressing level of prestressed tendon significantly influenced the seismic performance of prestressed high-strength concrete piles. Theoretical models were developed to predict cracking, yielding and ultimate bending resistances of the prestressed high-strength concrete pile under combined compression and bending. Finite element model was also developed to simulate the ultimate strength behaviour of the prestressed high-strength concrete pile under combined compression and flexural bending. The accuracies of the theoretical and finite element model were checked through validations of their predictions against the reported test results.

Research on Seismic Behaviour Factor of CBSF

2012 ◽  
Vol 166-169 ◽  
pp. 2326-2331
Author(s):  
Cheng Li ◽  
Jun Fen Yang ◽  
Qiang Gu
Keyword(s):  
Limit State ◽  
Element Model ◽  
Research Field ◽  
State Failure ◽  
Computation Method ◽  
Analysis Method ◽  
Seismic Behaviour ◽  
Behaviour Factor ◽  
Concentrically Braced ◽  
Concentrically Braced Steel Frame

In this paper,the definition and computation method of seismic behaviour factor is firstly explained,and then a V concentrically braced steel frame (CBSF) and an inverted-V CBSF were designed according to Chinese design codes,after that, the incremental dynamic analysis (IDA) was used to get the seismic behaviour factor.The results indicated that whether the connections between braces and columns or beams are rigid or hinged,which does not have much influence on the seismic behaviour factor of the structures.But the different seismic wave may bring different seismic behaviour factor for the same stuctures.Furthermore,the analysis method,limit state,failure criterion and finite element model of structures have some influrnce on the seismic behaviour factor of structures,and much work was needed in this research field.

Effect of cracks and pitting defects on gear meshing

2012 ◽  
Vol 226 (11) ◽  
pp. 2805-2815 ◽  
Author(s):  
Alfonso Fernandez del Rincon ◽  
Fernando Viadero ◽  
Miguel Iglesias ◽  
Ana de-Juan ◽  
Pablo Garcia ◽  
...  
Keyword(s):  
Finite Element ◽  
Computational Models ◽  
Inequality Constraints ◽  
Variable Stiffness ◽  
Element Model ◽  
Equation System ◽  
Transmission Error ◽  
Computational Effort ◽  
Gear Mesh ◽  
Non Linear

The development of vibration-based condition monitoring techniques, especially those focused on prognosis, requires the development of better computational models that enable the simulation of the vibratory behaviour of mechanical systems. Gear transmission vibrations are governed by the so-called gear mesh frequency and its harmonics, due to the variable stiffness of the meshing process. The fundamental frequency will be modulated by the appearance of defects which modify the meshing features. This study introduces an advanced model to assess the consequences of defects such as cracks and pitting on the meshing stiffness and other related parameters such as load transmission error or load sharing ratio. Meshing forces are computed by imposing the compatibility and complementarity conditions, leading to a non-linear equation system with inequality constraints. The calculation of deformations is subdivided into a global and a local type. The former is approached by a finite element model and the latter via a non-linear Herztian-based formulation. This procedure enables a reduced computational effort, in contrast to conventional finite element models with contact elements. The formulation used to include these defects is described in detail and their consequences are assessed by a quasi-static analysis of a transmission example.

Fatigue Analysis of Metallic Strips Flexible Pipe

2018 ◽  
Author(s):  
Guowei Sun ◽  
Peihua Han ◽  
Yuxin Xu ◽  
Yong Bai ◽  
Hamad Hameed
Keyword(s):  
Fatigue Life ◽  
Global Analysis ◽  
Element Model ◽  
Dynamic Responses ◽  
Flexible Pipe ◽  
Steel Strips ◽  
Counting Algorithms ◽  
Marine Engineering ◽  
Rainflow Counting ◽  
Specific Working

Metallic strips flexible pipe (MSFP) is widely regarded as an alternative for submarine pipelines. This paper presents a methodology for calculating the fatigue life of MSFP. Firstly, given a specific working condition of MSFP, the dynamic responses of MSFP are calculated through OrcaFlex. The obtained results from the global analysis are then implemented into a finite element model in ABAQUS to determine the stress-history curves of each steel strips layer. The estimated fatigue life is calculated by rainflow counting algorithms, S-N curve and Miner’s rule which are coded in MATLAB. Additional study about average stress correction is carried out, which might be useful for its marine engineering applications.

High Load Jacking Frames for Pin and Hanger Replacement at the Robert Moses Causeway

2020 ◽  
pp. 036119812095907
Author(s):  
Liwei Han ◽  
Qi Ye ◽  
Dan Wei
Keyword(s):  
New York ◽  
Computational Study ◽  
Global Analysis ◽  
Integrated Design ◽  
Integrated Approach ◽  
Efficient Design ◽  
Fully Integrated ◽  
Bridge Structures ◽  
Integrated Design Approach ◽  
Aging Steel

An innovative design of jacking frames was developed for pin and hanger replacement in Robert Moses Causeway (RMC) bridge in Suffolk County, New York. The robust and efficient design of the jacking frames results in a system with improved safety, performance, constructability, and economy. A fully integrated approach for design, fabrication, and construction was employed for higher quality and efficiency. A detailed and precise 3D model was created and directly used for finite element (FE) modeling, producing contract and shop drawings, and designing of temporary work platforms. This paper provides an overview of the integrated design approach and system design, and documents the computational study for this system (global analysis, stress analysis, and large-displacement stability analysis). There are many aging steel bridges in the U.S. and abroad that have similar pin and hanger systems, and jacking frames will be needed to replace those pins and hangers when they exhaust their useful service life. The concepts and details of the jacking frames can easily be emulated by engineers for developing similar safe and robust systems for suspended truss spans and other applicable bridge structures.

Study on FEM Analysis of Multistory Steel Frame Structure and its Optimal Design

2012 ◽  
Vol 433-440 ◽  
pp. 2194-2200
Author(s):  
Ru Wang ◽  
Long Qin ◽  
Zhen Qi Shao
Keyword(s):  
Optimal Design ◽  
Parametric Design ◽  
Fem Analysis ◽  
Element Model ◽  
Steel Frame ◽  
Frame Structure ◽  
Structural Element ◽  
Load Combination ◽  
Section Size ◽  
Steel Frame Structure

An finite element model (FEM) of multistory steel frame structure is established by applying ANSYS parametric design language(APDL) in this paper, where the objective function of optimization is defined as the minimum volume of a Pin framework. The optimal design are carried on by applying the optimized toolbox of ANSYS, based on analysis the situation of the most disadvantageous load combination. Several approaches have been proposed to avoid restraining to the local minimum. Experimental results show that the section size of the structural element improved obviously.

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