Visual programming for structural assessment of out-of-plane mechanisms in historic masonry structures

Funari, ‪Marco Francesco; Spadea, Saverio; Lonetti, Paolo; Fabbrocino, Francesco; Luciano, Raimondo

doi:10.1016/j.jobe.2020.101425

Cited by 39 publications

(36 citation statements)

References 38 publications

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“…In this paper, cracks are observed in local zones near the T-shaped flange in which compressive strength is relatively sufficient, and thus the tensile stresses, strains, and damage factors are the most concerned parts in the analysis. The role tensile stresses and damage variable play in crack developing and the structural strengthening effect of this case is similar with that in masonry collapse analysis and seismic assessment, reported in literatures [17,18], of which the literature [18] used the CDP model to access the structure's damage pattern. (1 ) ( )…”

Section: Numerical Modelingsupporting

confidence: 75%

Strengthening Mechanism of Studs for Embedded-Ring Foundation of Wind Turbine Tower

Chen

et al. 2021

Energies

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The embedded-ring wind turbine foundations were widely applied in the early development stage of wind power industries because of its properties such as easy installation and adjustment. However, different damages occurred on some embedded-ring wind turbine foundations in recent years. Based on the common damage phenomena of embedded-ring wind turbine foundations, the structural defects and damage mechanisms of embedded-ring wind turbine foundations are analyzed in a gradual way. Cheese head studs are proposed to be welded on the lateral wall of the steel ring to strengthen the connection between the steel ring and the foundation concrete. The foundation pier is elevated 1 m to increase the embedded depth of the steel ring. The circumferential confining pressure is applied on the lateral side of the foundation pier to lead it into a state of pressure. One simplified method is proposed to calculate the contribution of welding studs in this strengthening method. Taking an embedded-ring wind turbine foundation as an example, the numerical analyses for the original foundation and the reinforced one are carried out to compare the stress and strain distribution changes. Based on the numerical results corresponding to the peak and valley value loads, the fatigue life of the concrete and studs are evaluated according to the relevant design codes. The numerical results show that this strengthening method can coordinate the deformation of the embedded steel ring and the foundation concrete by circumferential prestressing and welding studs. The maximum principal stresses of the foundation pier and the fatigue stress range of the concrete around the bottom of the steel ring have been greatly reduced after strengthening. The gaps between the embedded steel ring and the foundation pier are also obviously decreased because of these strengthening measures. The stress concentration phenomena of the concrete around the T-shaped flange have been remarkably improved. The fatigue life can meet the requirements of relevant design codes after strengthening. Therefore, it can be concluded that the safety performance and service life of the embedded-ring foundation can be guaranteed.

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Section: Numerical Modelingsupporting

confidence: 75%

Strengthening Mechanism of Studs for Embedded-Ring Foundation of Wind Turbine Tower

Chen

et al. 2021

Energies

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“…Figure 8 shows the axial stress-strain behavior diagram in tension and pressure for concrete materials. In this figure, the model stiffness in loading is reduced by a factor of (1 − d c ) or (1 − d t ) [ 47 , 48 ]. In this form, ε t in and ε c in are the residual tensile and compressive strains in the case of non-damage, respectively, and ε t pl and ε c pl are the residual tensile and compressive strains in the case of concrete damage, respectively.…”

Section: Numerical Modelingmentioning

confidence: 99%

Numerical Modeling of Unreinforced Masonry Walls Strengthened with Fe-Based Shape Memory Alloy Strips

et al. 2021

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This study presents a new way to improve masonry wall behavior. Masonry structures comprise a significant part of the world’s structures. These structures are very vulnerable to earthquakes, and their performances need to be improved. One way to enhance the performances of such types of structures is the use of post-tensioning reinforcements. In the current study, the effects of shape memory alloy as post-tensioning reinforcements on originally unreinforced masonry walls were investigated using finite element simulations in Abaqus. The developed models were validated based on experimental results in the literature. Iron-based shape memory alloy strips were installed on masonry walls by three different configurations, namely in cross or vertical forms. Seven macroscopic masonry walls were modeled in Abaqus software and were subjected to cyclic loading protocol. Parameters such as stiffness, strength, durability, and energy dissipation of these models were then compared. According to the results, the Fe-based strips increased the strength, stiffness, and energy dissipation capacity. So that in the vertical-strip walls, the stiffness increases by 98.1%, and in the cross-strip model's position, the stiffness increases by 127.9%. In the vertical-strip model, the maximum resistance is equal to 108 kN, while in the end cycle, this number is reduced by almost half and reaches 40 kN, in the cross-strip model, the maximum resistance is equal to 104 kN, and in the final cycle, this number decreases by only 13.5% and reaches 90 kN. The scattering of Fe-based strips plays an important role in energy dissipation. Based on the observed behaviors, the greater the scattering, the higher the energy dissipation. The increase was more visible in the walls with the configuration of the crossed Fe-based strips.

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“…Casapulla et al [12,13] proposed a macro-block model coupled with a simplified procedure for predicting the collapse load and the failure mechanism of in-plane loaded masonry walls with non-associative frictional contact interfaces. The same authors [14] have recently revisited the previous macro-block approach implementing the frictional resistance computation.…”

Section: Introductionmentioning

confidence: 99%

A Tool for the Rapid Seismic Assessment of Historic Masonry Structures Based on Limit Analysis Optimisation and Rocking Dynamics

2021

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This paper presents a user-friendly, CAD-interfaced methodology for the rapid seismic assessment of historic masonry structures. The proposed multi-level procedure consists of a two-step analysis that combines upper bound limit analysis with non-linear dynamic (rocking) analysis to solve for seismic collapse in a computationally-efficient manner. In the first step, the failure mechanisms are defined by means of parameterization of the failure surfaces. Hence, the upper bound limit theorem of the limit analysis, coupled with a heuristic solver, is subsequently adopted to search for the load multiplier’s minimum value and the macro-block geometry. In the second step, the kinematic constants defining the rocking equation of motion are automatically computed for the refined macro-block model, which can be solved for representative time-histories. The proposed methodology has been entirely integrated in the user-friendly visual programming environment offered by Rhinoceros3D + Grasshopper, allowing it to be used by students, researchers and practicing structural engineers. Unlike time-consuming advanced methods of analysis, the proposed method allows users to perform a seismic assessment of masonry buildings in a rapid and computationally-efficient manner. Such an approach is particularly useful for territorial scale vulnerability analysis (e.g., for risk assessment and mitigation historic city centres) or as post-seismic event response (when the safety and stability of a large number of buildings need to be assessed with limited resources). The capabilities of the tool are demonstrated by comparing its predictions with those arising from the literature as well as from code-based assessment methods for three case studies.

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Visual programming for structural assessment of out-of-plane mechanisms in historic masonry structures

Cited by 39 publications

References 38 publications

Strengthening Mechanism of Studs for Embedded-Ring Foundation of Wind Turbine Tower

Strengthening Mechanism of Studs for Embedded-Ring Foundation of Wind Turbine Tower

Numerical Modeling of Unreinforced Masonry Walls Strengthened with Fe-Based Shape Memory Alloy Strips

A Tool for the Rapid Seismic Assessment of Historic Masonry Structures Based on Limit Analysis Optimisation and Rocking Dynamics

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