scholarly journals Parametric Stability Analysis of Groin Vaults

2021 ◽  
Vol 11 (8) ◽  
pp. 3560 ◽  
Author(s):  
Ricardo Maia Avelino ◽  
Antonino Iannuzzo ◽  
Tom Van Mele ◽  
Philippe Block

This paper presents a parametric stability study of groin, or cross vaults, a structural element widely used in old masonry construction, particularly in Gothic architecture. The vaults’ stability is measured using the geometric safety factor (GSF), computed by evaluating the structure’s minimum thickness through a thrust network analysis (TNA). This minimum thickness is obtained by formulating and solving a specific constrained nonlinear optimisation problem. The constraints of this optimisation enforce the limit analysis’s admissibility criteria, and the equilibrium is calculated using independent force densities on a fixed horizontal projection of the thrust network. The parametric description of the vault’s geometry is defined with respect to the radius of curvature of the vault and its springing angle. This detailed parametric study allows identifying optimal parameters which improve the vaults’ stability, and a comprehensive comparison of these results was performed with known results available for two-dimensional pointed arches. Moreover, an investigation of different force flows represented by different form diagrams was performed, providing a better understanding of the vaults’ structural behaviour, and possible collapse mechanisms were studied by observing the points where the thrust network touches the structural envelope in the limit states. Beyond evaluating the GSF, the groin vault’s stability domain was described to give additional insights into the structural robustness. Finally, this paper shows how advances in equilibrium methods can be useful to understand and assess masonry groin vaults.

2020 ◽  
Vol 92 (6) ◽  
pp. 51-58
Author(s):  
S.A. SOLOVYEV ◽  

The article describes a method for reliability (probability of non-failure) analysis of structural elements based on p-boxes. An algorithm for constructing two p-blocks is shown. First p-box is used in the absence of information about the probability distribution shape of a random variable. Second p-box is used for a certain probability distribution function but with inaccurate (interval) function parameters. The algorithm for reliability analysis is presented on a numerical example of the reliability analysis for a flexural wooden beam by wood strength criterion. The result of the reliability analysis is an interval of the non-failure probability boundaries. Recommendations are given for narrowing the reliability boundaries which can reduce epistemic uncertainty. On the basis of the proposed approach, particular methods for reliability analysis for any structural elements can be developed. Design equations are given for a comprehensive assessment of the structural element reliability as a system taking into account all the criteria of limit states.


2015 ◽  
Vol 76 (8) ◽  
Author(s):  
Thevaneyan K. David ◽  
Renga Rao Krishnamoorthy ◽  
Mohamed Jais I. B.

This paper presents background information relevant to the modelling of soil-structure interaction. The interaction between the structural element (i.e. pile foundation or abutments) and the soil medium is believed to have the potential to alter considerably the actual behaviour of any structure. Modelling of the structural element is rather simple and straightforward when compared to modelling the structure in interaction with soil. It is known that the structural analysis simplifies soil behaviour, while geotechnical analysis simplifies structural behaviour. The choice of an appropriate soil constitutive model may have significant influence on the accuracy of soil-structure interaction analyses. A 2D finite element analysis on a pile-cap-pile-soil model replicating actual field work was performed in this paper using OASYS SAFE to further substantiate the choice of an appropriate soil constitutive model for the purpose of soil-structure interaction modelling.


Author(s):  
Jani Romanoff ◽  
Heikki Remes ◽  
Petri Varsta ◽  
Bruno Reinaldo Goncalves ◽  
Ingrit Lillemäe-Avi ◽  
...  

Present paper gives an overview of the factors that affect the strength and structural design of advanced thin-walled marine structures with reduced plate thickness or alternative topologies to those used today in marine industry. Due to production-induced initial deformations and resulting geometrical non-linearity, the classical division between primary, secondary and tertiary responses becomes strongly coupled. Volume-averaged, non-linear response of structural element can be used to define the structural stress strain relation that enables analysis at the next, larger, length scale. This, today’s standard homogenization process needs to be complemented with localization, where the stresses are assessed at the details, such as welds for fatigue analysis. Due to this, the production-induced initial distortions need to be considered with high accuracy. Another key question is the length-scale interaction in terms of continuum description. Non-classical continuum mechanics are needed when consequtive scales are close. Strain-gradients are used to increase the accuracy of the kinematical description of beams, plates and shells. The paper presents examples of stiffened and sandwich panels covering limit states such as fatigue, non-linear buckling and fracture.


1989 ◽  
Vol 16 (6) ◽  
pp. 789-797 ◽  
Author(s):  
D. K. McNeely ◽  
G. C. Archer ◽  
K. N. Smith

The use of stone arches for bridge construction has generally ceased, but since these structures still exist in modern road systems, their structural integrity is of current concern. This paper presents an analysis technique suited for the thick jointed heritage stone arch bridges found in Canada. The effect of increased mortar joint size on structural response is investigated. The response of a section to eccentric thrust is postulated and the effective section properties are derived. Structural behaviour proceeds from a fixed arch to a two-hinge, a three-hinge, and finally a five-hinge failure mode for a symmetrical arch with midspan loading. A typical load–deflection curve is developed, suitably adjusted for secondary effects due to changes in geometry and material nonlinearity. Stone arch bridges in Canada were constructed with thick mortar joints, which exhibit significant deterioration of stiffness with load eccentricity and, therefore, significant secondary effects; as thickness increases, ultimate strength decreases. A suitable limit states prediction for the load capacity of old stone arches is proposed. Key words: arch, bridge, heritage, limit states, stone, structural analysis.


2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Jialu Wang ◽  
Xiaoyuan Liu

The flexure hinges are the most vulnerable parts in a flexure-based mechanism due to their smaller dimensions and stress concentration characteristics, therefore evaluating the maximum stresses generated in them is crucial for assessing the workspace and the fatigue life of the mechanism. Stress concentration factors characterize the stress concentrations in flexure hinges, providing an analytical and efficient way to evaluate the maximum stress. In this work, by using the ratio of the radius of curvature of the stress-concentrating feature to the minimum thickness as the only fitting variable, generalized equations for both the bending and tension stress concentration factors were obtained for two generalized models, the conic model and the elliptic-arc-fillet model, through fitting the finite element results. The equations are applicable to commonly used flexure hinges including circular, elliptic, parabolic, hyperbolic, and various corner-fillet flexure hinges, with acceptable errors. The empirical equations are tractable and easy to be employed in the design and optimization of flexure-based mechanisms. The case studies of the bridge-type displacement amplifiers demonstrated the effectiveness of the generalized equations for predicting the maximum stresses in flexure-based mechanisms.


2007 ◽  
Vol 34 (11) ◽  
pp. 1403-1412 ◽  
Author(s):  
Miha Tomaževič

The results of lateral resistance tests of masonry walls and shaking table tests of a number of models of masonry buildings of various structural configurations, built with various materials in different construction systems, have been analyzed to find a correlation between the occurrence of different grades of damage to structural elements, characteristic limit states, and lateral displacement capacity. On the basis of correlation between acceptable level of damage and displacement capacity, it has been shown that the range of elastic force reduction factor values used to determine the design seismic loads for different masonry construction systems proposed by the recently adopted European standard Eurocode 8 EN-1998-1 for earthquake resistant design are adequate. By using the recommended design values, satisfactory performance of the masonry buildings that have been analyzed may be expected when subjected to design intensity earthquakes with respect to both the no-collapse and damage-limitation requirements.


2016 ◽  
Vol 2 (2) ◽  
pp. 40
Author(s):  
Concepción Río Vega ◽  
Ana Ribas Sangüesa

ResumenLa fachada autoportante de ladrillo cara vista es el resultado de una profunda reflexión sobre las diferentes soluciones de fachada de ladrillo que se han utilizado a lo largo de la historia. Ha sido promovida por Hispalyt en estrecha colaboración con el Departamento Técnico de Geohidrol S.A., empresa líder en la investigación, fabricación y comercialización de sistemas para cerramientos de fábrica. Cuando se analizan las diferentes soluciones de las fachadas de ladrillo, bajo la óptica de los requisitos del Código Técnico de la Edificación, la fachada autoportante 'STRUCTURA' se manifiesta como la solución óptima por su simplicidad, sus elevadas prestaciones y el bajo coste en recursos auxiliares. La fachada autoportante 'STRUCTURA' se caracteriza porque la hoja exterior del cerramiento se construye totalmente separada del edificio, gravitando sobre sí misma, lo cual permite la disposición de una cámara de aire (ventilada o no) con aislamiento térmico continuo. De esta forma se elimina el puente térmico en el encuentro con los frentes de pilares y forjados, mejorando notablemente el rendimiento higrotérmico del edificio con el fin de cumplir el Documento Básico de Ahorro de Energía (DB HE), cuyos requisitos en la nueva versión aprobada en Septiembre de 2013 han experimentado un sustancial incremento respecto de los contenidos en la versión anterior. Desde el punto de vista de la respuesta mecánica, la fachada autoportante se fundamenta en el aprovechamiento del potencial que tienen los muros de ladrillo cuando se utilizan como soportes de sí mismos. A diferencia de las soluciones convencionales o de las que requieren elementos auxiliares de sostén dispuestos planta a planta, con la solución 'STRUCTURA' el muro de ladrillo se analiza como un elemento activo en el comportamiento estructural, de manera que su propio peso contribuye beneficiosamente en la resistencia frente a las acciones horizontales.AbstractThe self-supporting face brick façade is the result of a profound reflection on the different solutions for the brick façades that have been used throughout history. It has been promoted by Hispalyt in close collaboration with the Technical Department of Geohidrol S.A., leader company in the research, manufacture and marketing of systems for masonry closings. When analyzing different solutions of face brick façade, under the perspective of the technical building code requirements, the self-supporting façade 'STRUCTURA' appears as the optimal solution for its simplicity, high performance and low cost in auxiliary resources. The self-supporting façade 'STRUCTURA' is characterised by the outer leaf of the enclosure being built fully separately from the building, supported on itself, and thus enabling the provision of an air chamber (ventilated or not) with continuous thermal insulation. In this manner thermal bridges on the fronts of pillars and floors are eliminated, noticeably improving the hygrothermal performance of the building in order to comply with the technical building code basic document for energy saving (DB HE), whose requirements in the new version approved in September 2013 have substantially increased with respect to the requirements of the previous version. From the point of view of the mechanical response, the self-supporting façade is based on exploiting the potential that brick walls have when used as a load-bearing structural element themselves. Unlike conventional solutions or those that require additional support devices arranged floor-to-floor, with the 'STRUCTURA' solution the brick wall is analyzed as an active element in the structural behaviour, so that its own weight contributes beneficially to the resistance against horizontal actions.


2015 ◽  
Vol 1106 ◽  
pp. 168-171 ◽  
Author(s):  
Radovan Hofírek ◽  
Miloš Zich

In concrete structures such as bridges or tanks, hydro insulation is applied several months after the actual construction of the structure itself. Concrete structures dry during part of their lifespan throughout the entire area of their structure. After hydro insulation is applied, drying is affected and it does not occur as it would under normal conditions. This change in drying conditions can eventually lead to changes in the structural behaviour of the structure e.g. bridges or tanks. Current computing programmes for time dependent analysis of the structure do not allow to take into consideration the above mentioned conditions while drying takes place, thus leading to static analysis inaccuracies [2]. The aim of this research is to experimentally demonstrate shrinkage as a result of the difference in drying of the concrete structural element ́s cross-section and their basic comparison with the calculations according to different standards.


2021 ◽  
Vol 1 (63) ◽  
pp. 44-52
Author(s):  
T. Volina ◽  
◽  
S. Pylypaka ◽  
V. Babka ◽  
◽  
...  

The rough plane is a universal structural element of many machines and devices for sifting and separation of parts of technological material. The motion of particles on the horizontal plane, which performs oscillating rectilinear or circular motion, is the most studied. A wavy surface with a sinusoidal cross-sectional line as a working surface will significantly change the trajectories of their motion. The mathematical description of such a motion will change accordingly. The sliding of a particle in a plane will be a partial case of sliding on a wavy surface when the amplitude of the sinusoid is equal to zero. When the wavy surface oscillates and all its points describe circles, the motion of the technological material changes significantly. The regularities of the motion of material particles on such a surface during its circular translational oscillations in the horizontal planes are investigated in the article. Differential equations of relative particle displacement are compiled and solved by numerical methods. The trajectories of the particle sliding on the surface and the graphs of its reaction are constructed. A partial case of a surface is a plane, and the sliding trajectory of a particle is a circle. An analytical expression to determine its radius is found. During circular oscillations of a wavy linear surface with a cross section in the form of a sinusoid relative trajectory of a particle after stabilization of the motion can be closed or periodic spatial curves. To avoid the breakaway of the particle from the surface, the oscillation mode should be set, which takes into account the shape of the surface and the kinematic parameters of oscillations. With the diameter of the circle, which is described by all points of the surface during its oscillation, is equal to the period of the sinusoid, the trajectory of the relative motion of the particle can be a periodic curve. In this case, the particle moves in a direction close to the transverse, overcoming depressions and ridges. In other cases, the trajectory is a closed spatial curve, the horizontal projection of which is close to a circle. The found analytical dependencies allow determining the influence of structural and technological parameters of the surface on the trajectory of the particle.


Author(s):  
B. Riveiro ◽  
G. Cubreiro ◽  
B. Conde ◽  
M. Cabaleiro ◽  
R. Lindenbergh ◽  
...  

In present work it is pretended to estimate elastic parameters of beams through the combined use of precision geomatic techniques (laser scanning) and structural behaviour simulation tools. The study has two aims, on the one hand, to develop an algorithm able to interpret automatically point clouds acquired by laser scanning systems of beams subjected to different load situations on experimental tests; and on the other hand, to minimize differences between deformation values given by simulation tools and those measured by laser scanning. In this way we will proceed to identify elastic parameters and boundary conditions of structural element so that surface stresses can be estimated more easily.


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