Search results for "construct"
showing 10 items of 3723 documents
Geometric deformation measurement and correction applied to dynamic streak camera images
2002
The complete procedure of measuring and correcting geometric deformations encountered with dynamic streak camera images in the picosecond range is presented and discussed. First, we describe the experimental setup derived from the well known spacing calibration grid method. The implemented measurement bench, adapted to time-resolved 1D imaging, notably exhibits a great accuracy and repeatability both in space and time thanks to a three-axis motorized translation stage and programmable delay lines. Second, we examine image restoration by two different analytical transform means (local versus global): results and performances of both are compared. Then we deal with final image reconstruction …
Experimental investigation on BFRCM confinement of masonry cylinders and comparison with BFRP system
2021
Abstract Fabric reinforced cementitious mortar (FRCM) materials have started to be employed during the last years with the aim of overcoming the drawbacks related to the use of fibre reinforced polymer (FRP) composites, proving to be potentially suitable for strengthening masonry structures. Moreover, the will to develop materials able to guarantee a certain degree of sustainability without renouncing to adequate mechanical properties has drawn the attention to the use of basalt fibres, which appear to be a valid alternative to carbon or glass fibres. This work presents an experimental investigation on a basalt FRCM (BFRCM) system to confine circular masonry columns, aimed at evaluating the…
Stress transfer mechanism investigation in hybrid steel trussed-concrete beams by push-out tests
2014
Abstract Results of push-out tests carried out on Hybrid Steel Trussed–Concrete Beams (HSTCBs) before and after the concrete casting are presented and interpreted. Firstly, in order to check the ability of weldings before casting, tensile tests were performed on specimens reproducing different types of welded joints. Simplified design formulae were used to predict their ultimate strength. Secondly, results obtained by push-out tests on specimen representative of the beam before and after the concrete casting are presented and discussed. Finally, simplified analytical models proposed by the current European building code were adapted to the specific typology to roughly predict the ultimate s…
FEM analysis of push-out test response of Hybrid Steel Trussed Concrete Beams (HSTCBs)
2015
Abstract Aiming to investigate the steel truss–concrete stress transfer mechanism in Hybrid Steel Trussed–Concrete Beams (HSTCBs), a three-dimensional (3D) nonlinear Finite Element (FE) model is developed. The constitutive relationship of the steel composing the plates and the rebars is modeled by means of a quadri-linear law, while the concrete behavior is defined by means of a Concrete Damaged Plasticity (CDP) model, suitable for modeling concrete and brittle materials. Two main failure mechanisms are considered, namely the tensile cracking and the compressive crushing. In order to accurately grasp the complicate dowel and bond phenomena arising at the steel–concrete interface, a 3D solid…
Strength and strain enhancements of concrete columns confined with FRP sheets
2004
The compressive behavior up to failure of short concrete members reinforced with fiber reinforced plastic (FRP) is investigated. Rectangular cross-sections are analysed by means of a simplified elastic model, able also to explain stress-concentration. The model allows one to evaluate the equivalent uniform confining pressure in ultimate conditions referred to the effective confined cross-section and to the effective stresses in FRP along the sides of section; consequently, it makes it possible to determine ultimate strain and the related bearing capacity of the confined member corresponding to FRP failure. The effect of local reinforcements constitute by single strips applied at corners bef…
Limited Resistance Rigid Perfectly Plastic Hinges for Steel Frames
2017
The paper concerns the proposal of a new special device for steel frames that can be utilized as external constraint as well as internal one connecting the structure beam elements. The device is designed as a rigid perfectly plastic hinge characterized by suitably chosen stiffness and resistance. Its constituting material is steel. The elastic stiffness and the limit resistance, treated as independent of each other, are fixed with the aim of satisfying special features required to the structure. The proposed device is thought as a sandwich section with wing thickness appropriately variable. Its dimensions are designed so that it can exhibit the fixed independent stiffness and limit resistan…
Revista electrónica de investigación y evaluación educativa
2010
Este trabajo tiene el propósito de mostrar el uso de la metodología de Modelos de Ecuaciones Estructurales (SEM) para validar la estructura conceptual de cuestionarios de contexto que se utilizan en los estudios nacionales e internacionales para evaluar el logro educativo de los escolares. Desgraciadamente, los organismos evaluadores no destinan los mismos recursos técnicos a los cuestionarios de contexto que a las pruebas de aprendizaje, por lo que rara vez los primeros son sujetos a estudios de validez. Para mostrar el uso de la metodología SEM, se seleccionó el cuestionario dirigido a alumnos que utilizó el Instituto Nacional para la Evaluación de la Educación (INEE) para conocer los fac…
A tool for a first analysis of architectural façades
1997
Abstract This work presents a tool for analysing the figurative structure of architectural facades. The procedure begins by singling out the elementary shapes which make up the facade image; it detects and identifies them as “area objects”, even if present in combination in virtual or mental form and groups them into classes of equal objects. A second step is the analysis of the inner structure of the classes: equidistant, arithmetical and geometrical sequences, or alternate distances are distinguished. The procedure ends by singling out the symmetries which structure the facade image and displaying them, pointing out their implied hierarchy through a thickness differentiation.
Theoretical and Experimental Model for the Analysis of a Cardan Cross
2015
The work presents the aproach of initial moddeling and calculus in order to prepare an finite element investigation of the cardan transmission joint. For this, it is necessary to develop a flexible informational system that would connect the constructive design of cardan transmissions to the technological design within a unitary structure. Due to the typodimensional diversity of cardan transmissions, the design and manufacturing of the various components for a certain application domain (medical aparature, dental and agricultural machines, lifting and transportation machines etc.) has been typified. In order to study the problems that occur in the practice of using cardan transmissions, the…
Groups are not always the same
1993
The idea of supporting group meetings at the same time and at the same place by computer raises the problem of how salient features of group behaviors are understood in meetings. In this paper we take a critical look at several beliefs about group behaviors in research dealing with electronic meeting systems (EMS). The paper argues based on an empirical study that the concept of a small, cohesive business team, so widely held, in all EMS research is not necessarily a valid starting point in thinking of meeting support. In particular, the paper critically evaluates a number of beliefs of user aspects, group features such as composition, structure and protocols, and task characteristics such …