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EN
Purpose: The purpose of the research is to study the deformability of glass multilayer columns at the central compression using digital image correlation. It becomes possible to use the method of digital image correlation for the experimental study of load bearing building structures of glass. Design/methodology/approach: The approach which has been used to solve the above problems is to conduct an experimental study of glass columns on central compression, in which deformations were measured using digital image correlation. Findings: The possibility of using load bearing building structures of glass triplex has been discovered. A program of experimental studies was developed. It included the testing of prototype samples on central compression with rigid fastening. On the basis of the obtained results, a graph of dependence of relative deformations on normal tension, graphs of the dependence of the bending of columns on load in different planes, and a modulus of elasticity of triplex glass have been determined. Research limitations/implications: The lack of a calculation methodology and regulatory documents for designing load bearing building structures of triplex glass increases their cost, since each project is individual and requires the experimental research. Practical implications: Using the approaches developed in the paper, the method of digital image correlation, which is to measure deformations when testing glass structures on central compression can be applied. Originality/value: The experimental study is probably the first one in which deformations of glass columns are determined using the method of digital image correlation, so it is new and original. The lack of a calculation methodology and regulatory documents for designing load bearing building structures of triplex glass, increases their cost, since each project is individual and requires the experimental research.
EN
Purpose: of this paper presents the experimental results of a study of strength and flexural behaviour of non-autoclaved foam-concrete beams reinforced with bamboo Design/methodology/approach: Six experimental samples of reinforced lightweight foamed concrete beams with hardened density D800 and D1200 with the same bamboo reinforcement were tested on lateral bending. Findings: A low level of anchoring of bamboo reinforcement in foam-concrete beams can provide their premature destruction. Research limitations/implications: Next experiments should be provided for improving the anchoring of bamboo reinforcement such as the bad adhesion between the bamboo and foam-concrete caused premature destruction of experimental samples. Practical implications: Replacement of steel reinforcement on the bamboo one in foamconcrete structures can be economical benefit. Originality/value: Increasing of experimental base leads to developing and creating new building standards in the nearest future.
3
Content available remote Flexural strength of glass using Weibull statistic analysis
EN
Purpose: The aim of the study is to measure the flexural strength of glass by proposed experimental procedures. In addition, step-by-step guidelines for the strength data analysis using a two-parameter Weibull distribution are given. Design/methodology/approach: Twelve glass samples of three series were tested by three-point bending with horizontal ‘3PB(H)’ and vertical ‘3PB(V)’ orientation of samples. A two-parameter Weibull distribution was applied as an appropriate model to describe three strength data sets for glass. Findings: The experiments performed on nominally identical glass specimens revealed a wide range of flexural strength values, from 39.77 MPa to 171.71 MPa at a loading rate of not more than 1.05 MPa/s. 3PB(V) samples with vertical orientation demonstrated the flexural strength similar to that of 3PB(H) samples with horizontal orientation. The Weibull modulus, which is the measure of flexural strength variation, was between 2.04 and 5.23 at the coefficient of determination R2 greater than 90% for all series. The characteristic values of the glass strength, corresponding to the 5% fractile value, in accordance with the test evaluation procedure were 23.71 MPa, 31.98 MPa, 53.43 MPa for the first, the second and the third test series, respectively. Research limitations/implications: The maximum flexural strength of glass highly depends on the surface condition, and therefore the strength of the glass of different batches is variable whatever the case may be. For the guaranteed strength of glass used for structural purposes it is necessary to conduct strength tests of the glass from each batch under conditions that closely correspond to actual operating conditions. Practical implications: The obtained strength data is needed for designing glass load bearing constructions subjected to actual operating conditions (e.g. multilayered glass plates working on bending under static loading). Originality/value: A comprehensive overview of the existing methods for glass strength testing was presented. The features of the used flexural tests and the statistical analysis of the measured strength data were described. The results may be of a particular interest to the specialists in the modern design of load bearing glass constructions.
4
Content available Experimental research of woodenarches
EN
This paper presents the findings of the pilot studies of two-hinged wooden arches. The prototype models of wooden arches with the span of 6m and the rise of 1m were designed. The models had a rectangular cross-section of 180x40mm and a T-section of 180x40mm with a plywood plate with the thickness of 6 mm and the width of 500mm. The main objective of the T-section was to ensure the stability of the arch. Each arch was composed of six segments – boards joined by clamping plates. The bowstring truss including two inclined tie bars enables carrying asymmetric loads and provides in-plane stability of the arch. A methodology for laboratory testing of the prototype models of wooden arches subjected to different types of loads was developed. Two prototypes of wooden arches were tested with rectangular cross-sections and two T-section ones subjected to the loading across the span, and two prototypes subjected to the half-span loading. In total, eight arches were tested. Deflections of arches, cross-section deformations and arch thrust force were recorded. The arches were tested until failure. The results of testing revealed insufficient stability of the arches with rectangular cross-section in the horizontal plane. For the arches with T-section the whole arch rib was damaged, the in-plane stability was ensured by the T-section. The collapsing force of the T-section arch was about 1.3times greater than the collapsing force of the rectangular section arches.
PL
W niniejszym artykule przedstawiono wyniki eksperymentalnych badań dwuprzegubowych drewnianych łuków. Skonstruowano badawcze modele drewnianych łuków o rozpiętości 6 m i strzałce 1 m. Modele do badań miały przekrój prostokątny o wymiarach 180x40 mm oraz przekrój teowy ze środnikiem 180x40mm i półką ze sklejki o grubości 6 mm i szerokości 500 mm. Głównym zadaniem przekroju teowego było zabezpieczenie stabilności łuku. Każdy łuk składał się z sześciu elementów – desek, które były połączone między sobą za pomocą płytek kolczastych. W łuku było poziome stężenie z kabla dla przeniesienia sił poziomych od rozporu konstrukcji oraz dwóch pochyłych stężeń z kabli dla przeniesienia niesymetrycznych obciążeń i zabezpieczenia stabilności w płaszczyźnie łuku. Opracowano metodę badania eksperymentalnych wzorców drewnianych łuków w warunkach laboratoryjnych na działanie różnych rodzajów obciążeń. Wypróbowano po 2 badawcze wzorce drewnianych łuków o przekroju prostokątnym i przekroju teowym na działanie obciążenia na całej rozpiętości, a także po 2 badawcze wzorce przy działaniu obciążenia na połowie rozpiętości. W sumie zbadano 8 łuków. W trakcie eksperymentu były odczytywane ugięcia łuku, odkształcenia w przekrojach poprzecznych oraz naprężenia rozciągające w stężeniach. Łuki były badane do całkowitego zniszczenia. W wyniku badań łuków o przekroju prostokątnym ustalono ich niedostateczną stabilność w poziomej płaszczyźnie. Łuki o przekroju teowym niszczyły się w przekroju łuku, ich stabilność z płaszczyzny była zabezpieczona przekrojem teowym. Niszczące obciążenia w łukach o przekroju teowym średnio były 1,3 razy większe od niszczących obciążeń łuków o przekroju prostokątnym.
EN
The article is devoted to particularly important contemporary problems, namely usage of energy-saving and ecological materials in load-bearing structures of buildings. This issue is discussed in the paper in respect of floor slabs. We propose to combine traditional materials (concrete and steel reinforcement) with energy--efficient material (non-autoclaved foamed concrete) in floor slabs structure. It is assumed that employment of precast-monolithic reinforced concrete floor slab with usage of non-autoclaved foamed concrete can afford to decrease dead weight of floor and foundation loading, and to guarantee good thermal and acoustic insulation between storeys.
PL
Artykuł poświęcony jest szczególnie ważnym problemom współczesności, a mianowicie zastosowaniu energooszczędnych i ekologicznych materiałów budowlanych. Problemy te odnoszą się w prezentowanym artykule do płyt stropowych. Proponuje się połączenie w konstrukcji płyt stropowych materiałów tradycyjnych (beton zwykły i pręty zbrojeniowe) z materiałem energooszczędnym (nieautoklawizowanym pianobetonem). Zakłada się, że zastosowanie stropowych płyt prefabrykowano-monolitycznych z wykorzystaniem nieautoklawizowanego pianobetonu pozwoli zmniejszyć całkowity ciężar stropu i obciążenie fundamentu, zapewnić dobrą izolacyjność cieplną i akustyczną pomiędzy piętrami.
6
Content available remote Evaluation of reinforcement bonding in foam concrete
EN
The presented study is devoted to experimental research of the reinforcing bar and foam concrete bonding phenomenon and the estimation of its durability. It is set that the reason of early destruction of the reinforced foam concrete beam structures is the inefficient reinforcing bar and foam concrete bonding. The authors present a method of calculation of bonding stresses on the edge of bar contact with the array of foam concrete, which are defined from the condition of the accepted rectangular distribution diagram of stresses on the length of anchoring. Two types of diagrams are made for usage within the offered engineering method of calculation of bonding strength of both smooth and ribbed reinforcement with foam concrete of different density. The way of improvement in safety of the reinforced foam concrete constructions is specified through the use of anchors.
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