Search results for "CONSTRUCTION"
showing 10 items of 2670 documents
LRPH device optimization for axial and shear stresses
2020
The paper concerns an in-depth study of a special connection for steel structures and the formulation of the related optimal design problem. The connection is called Limited Resistance Rigid Perfectly Plastic Hinge (LRPH) and it represents an innovative device devoted to join steel beam elements of frame structures. The device consists in a sequence of steel cross sections constituted by two parallel flanges with suitably different thickness connected by as many webs with constant and equal thickness. The fundamental innovation of the device is the possibility of designing special connections with elastic stiffness and limit strength independent of each other. Such a special characteristic …
Theoretical elastoplastic buckling of stringer stiffened cylindrical shells
1985
Abstract A linear analysis method is offered to predict the theoretical elastoplastic buckling of stringer stiffened cylindrical shells subjected to longitudinal loading. Welding residual stresses are taken into account in the calculation, but effects of geometrical imperfections and pre-buckling displacements are ignored. The examples analysed show a good correlation between the analytical results and those obtained experimentally with stocky models of moderate geometrical imperfections.
Effects of Different Test Setups on the Experimental Tensile Behaviour of Basalt Fibre Bidirectional Grids for FRCM Composites
2020
Fibre-reinforced cementitious matrix (FRCM) composites have been effectively used during the last ten years for the strengthening of existing concrete and masonry structures. These composite materials are made of medium- and high-strength fibre meshes embedded in inorganic matrices. Synthetic fibres are the ones that are currently the most used
Effect of the fiber geometry on the pullout response of mechanically deformed steel fibers
2013
Abstract A simple model to predict the influence of fiber geometry on the pullout of mechanically deformed steel fibers from cementitious matrix is proposed. During the pullout the mechanically deformed fiber is subjected to repetitive bending and unbending which cause an increase of the tension in the fiber. This increase of the tension depends on the amount of plastic work needed to straighten the fiber during pullout. The model input parameters are mechanical and geometrical properties of mechanically deformed fibers. Model predictions were compared to the experimental results on the hooked-end and crimped steel fiber pullout and good agreement was observed.
Effectiveness of stirrups and steel fibres as shear reinforcement
2004
This paper presents the results of experimental tests carried out on rectangular simply supported beams made of hooked steel fibre reinforced concrete with and without stirrups, subjected to two-point symmetrically placed vertical loads. The tests, carried out with controlled displacements, allow one to record complete load-deflection curves by means of which it is possible to deduce information on dissipative capacity and ductile behaviour up to failure. Depending on the amount of transverse reinforcement, volume fraction of fibres added in the mix and shear span, the collapse mechanism is due to predominant shear or flexure, thus showing the influence of the aforementioned structural para…
Effect of corner over-reinforcing strips on the compressive behaviour of TRM confined masonry columns
2020
Several recent works studied the efficiency of inorganic matrix composites, namely Textile Reinforced Mortar (TRM) or Fabric Reinforced Cementitious Matrix, for enhancing the strength and shortening capacity of masonry columns subjected to axial load. Literature studies were addressed to study the great number of variables involved in the problem, such as the nature and the grade of mortar, the strength of the fabric, the number of reinforcing layers, the type, the arrangement and the strength of the masonry, and helped to draw the first technical guidelines for practitioners and designers. All the experimental works highlighted that the actual performance of TRM confinement in masonry memb…
Random short sisal fiber biocomposites: Optimal manufacturing process and reliable theoretical models
2018
Although several works have been published in literature on agave fibers and their biocomposites, accurate information about the choice of both the fibers and the manufacturing processes that allow the user to optimize the biocomposites properties in terms of strength and stiffness are not yet available; also, no theoretical models that can be used for an accurate evaluation of the mechanical properties of these biocomposites, are reported.To this aim, the present work intends to give a contribution by considering green epoxy biocomposites reinforced by both short and discontinuous sisal agave fibers arranged in proper MAT-type fabrics. In particular, an optimized manufacturing process that…
General stress-strain model for concrete or masonry response under uniaxial cyclic compression
2002
The paper proposes analytical forms able to represent with very good approximation the constitutive law experimentally deducible by means of uniaxial cyclic compressive tests on material having softening post-peak behaviour in compression and negligible tensile strength. The envelope, unloading and reloading curves characterizing the proposed model adequately approach structural responses corresponding to different levels of nonlinearity and ductility, requiring a not very high number of parameters to be calibrated experimentally. The reliability of the model is shown by comparing the results that it is able to provide with the ones analytically deduced from two reference models (one for co…
The influence of steel fibres on compressive and tensile strength of ultra high performance concrete : A review
2020
Abstract This review paper presents the effects of steel fibre reinforcement regarding the compressive and tensile strength of UHPC. The intention is to give an overview of the research field and supply guidance for future research. Relevant papers were identified through a systematic literature search. An accumulation of the results shows that fibres have potential for improving the tensile strength of UHPC. The effect depends on fibre content, type and hybrid combinations. The effect of fibres on compressive strength seems to be questionable. Variations in test specimen geometry and other factors might also influence the results.
Laboratory Tests for Assessing the Reliability and Durability of Innovative Cold-Glued 3D Glass Building Subcomponents
2020
The paper shows the results of analyses of the behavior of an innovative subcomponent made of two glass shells and a plastic thermal belt interfaced with a resin-based adhesive, in order to define the plastic material–adhesive combination able to guarantee compliance with the requirements related to mechanical strength, thermoacoustic insulation, dimensional stability, material compatibility, and durability. Two different types of ultraviolet (UV)-curing adhesive were used to establish the best plastic–adhesive combination. A study of the mechanical behavior and the reliability over time of the bonded assembly was conducted by performing accelerated weathering tests and tensile tests on 30 …