Design properties of laterally loaded nailed or bolted wood joints

1988 ◽  
Vol 15 (4) ◽  
pp. 633-643 ◽  
Author(s):  
Ian Smith ◽  
Luke R. J. Whale ◽  
Colin Anderson ◽  
Barry O. Hilson ◽  
Peter D. Rodd
Keyword(s):  
Mechanical Properties ◽  
Key Words ◽  
Bolted Joints ◽  
Design Codes ◽  
Short Term ◽  
Limit States ◽  
Design Solutions ◽  
Reliable Knowledge ◽  
Laterally Loaded

This paper summarizes the output from a long-term project commenced in 1980 with the objective of providing reliable knowledge of the mechanical properties of nailed or bolted joints subjected to short-term lateral loadings. Motivation was the development on an international basis of probability-based partial coefficients limit states design codes for structural timberwork. Comparisons are presented between design solutions produced by applying this research and those by the use of contemporary "soft conversion" international partial coefficients limit states design codes that were calibrated from previously available data. Differences relate primarily to design of bolted joints. It is shown that there is an established acceptance in Canada of the approach adopted. Key words: wood, joints, nails, bolts, design.

Long-Term Deformations of Strengthened Reinforced Concrete Linear Elements

2016 ◽  
Vol 691 ◽  
pp. 51-60 ◽  
Author(s):  
Martin Krizma ◽  
Lubomir Bolha
Keyword(s):  
Reinforced Concrete ◽  
Long Term Results ◽  
Short Term ◽  
Limit States ◽  
Linear Elements ◽  
Repeated Load ◽  
The Moment ◽  
Concrete Elements ◽  
Fiber Fabric

The issue of strengthening the damaged linear reinforced concrete elements have been engaged since 2008. We focused on the analysis of resistance and the characteristics of limit states of serviceability in the damaged and subsequently strengthened elements at a short-term loading. In the introduction phase, the strengthening of the elements was carried out with the following procedures – installation of an overlayer on the coupling board or a combination of the board and use of glass – fiber fabric (GFRP). The strengthening was also affected by the type of contact (reinforced/non-reinforced) – the deformed element/coupling board and its effect on resistance, type of deformation and serviceability. In the non-reinforced contact, we applied some of the types of adjustments to the surface of the strengthened element. At the moment, we are dealing with the effects of time and repeated load on the strengthened elements. The results correspond to the reinforced contact. The values are compared with the short-term results of the strengthened beams and with the long-term results of the beams prepared for strengthening.

scholarly journals Influence of Gradation on the Mechanical Properties of Aged Hot-Mix Asphalts

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 632
Author(s):  
Saieth Baudilio Chaves-Pabón ◽  
Hugo Alexander Rondón-Quintana ◽  
Carlos Alfonso Zafra-Mejía
Keyword(s):  
Mechanical Properties ◽  
Cyclic Load ◽  
Stress Condition ◽  
Resilient Modulus ◽  
Permanent Deformation ◽  
Short Term ◽  
Clear Trend ◽  
Indirect Tensile ◽  
Effects Of Aging

When a hot-mix asphalt (HMA) ages, its mechanical properties, resistance, and durability change. Several studies have been conducted throughout the world to evaluate the effects of aging in HMAs. However, few studies have analyzed the influence of gradation. The main objective of this study was to evaluate the influence of gradation on the mechanical properties of aged HMA mixes. For such purposes, three HMA mixes with different gradations were manufactured (named HMA-10, HMA-19, and HMA-25), which were conditioned in STOA (short-term oven aging) and LTOA (long-term oven aging) by following the guidelines established by the AASHTO R30 specification. Marshall, Indirect Tensile Strength (ITS), resilient modulus, permanent deformation, fatigue (under controlled-stress condition), and Cantabro tests were performed. These tests were carried out to evaluate resistance under monotonic and cyclic load as well as the resistance to moisture damage and abrasion. The best performing mix in the test was HMA-19. There is no clear trend about the influence of gradation over the susceptibility of mixes for aging. This susceptibility changes depending on the test performed and the property measured. Furthermore, in resilient modulus tests, it is observed that the influence of gradation on aging susceptibility changes depending on the test temperature.

scholarly journals The Effects of Various Conditions of Short-Term Rejuvenation Heat Treatment on Room-Temperature Mechanical Properties of Thermally Aged P92 Boiler Steel

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6076
Author(s):  
Ladislav Falat ◽  
Lucia Čiripová ◽  
Viera Homolová ◽  
Miroslav Džupon ◽  
Róbert Džunda ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Toughness ◽  
Room Temperature ◽  
Laves Phase ◽  
Short Term ◽  
Boiler Steel ◽  
P92 Steel ◽  
The Impact

In this work, the effects of various conditions of short-term rejuvenation heat treatment on room-temperature mechanical properties of long-term aged P92 boiler steel were investigated. Normalized and tempered P92 steel pipe was thermally exposed at 600 °C for time durations up to 5000 h in order to simulate high-temperature material degradation, as also occurring in service conditions. Thus, thermally embrittled material states of P92 steel were prepared, showing tempered martensitic microstructures with coarsened secondary phase precipitates of Cr23C6-based carbides and Fe2W-based Laves phase. Compared with the initial normalized and tempered material condition, thermally aged materials exhibited a slight decrease in strength properties (i.e., yield stress and ultimate tensile strength) and deformation properties (i.e., total elongation and reduction of area). The hardness values were almost unaffected, whereas the impact toughness values showed a steep decrease after long-term ageing. An idea for designing the rejuvenation heat treatments for restoration of impact toughness was based on tuning the material properties by short-term annealing effects at various selected temperatures somewhat above the long-term ageing temperature of P92 material. Specifically, the proposed heat treatments were performed within the temperature range between 680 °C and 740 °C, employing variable heating up and cooling down conditions. It was revealed that short-term annealing at 740 °C for 1 h with subsequent rapid cooling into water represents the most efficient rejuvenation heat treatment procedure of thermally aged P92 steel for full restoration of impact toughness up to original values of normalized and tempered material state. Microstructural observations clearly indicated partial dissolution of the Laves phase precipitates to be the crucial phenomenon that played a key role in restoring the impact toughness.

Study of the Influence of the Chemical Resistance of Polyphenylenesulphone from Radel on Mechanical Properties

2021 ◽  
Vol 899 ◽  
pp. 245-252
Author(s):  
Elena V. Rzhevskaya ◽  
Vladlena V. Davydova ◽  
Igor V. Dolbin
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Chemical Resistance ◽  
Short Term ◽  
Chemical Reagents

The paper presents the results of a study of the chemical resistance and mechanical properties of polyphenylene sulfone manufactured by Solvay, Radel brand, obtained by injection molding. Chemical resistance was investigated in short-term tests (24 hours duration), standard (7 days) and long-term (16 weeks). The mechanics of PPSU samples after exposure to chemical reagents is presented. It was revealed in what chemical environments and how much the mechanical properties of polyphenylene sulfone are preserved.

The Effect of Ageing on the Micro-Creep Properties of Radiation Cross-Linked Materials

2016 ◽  
Vol 368 ◽  
pp. 134-137
Author(s):  
Martin Řezníček ◽  
Martin Ovsík ◽  
Adam Škrobák ◽  
David Manas
Keyword(s):  
Mechanical Properties ◽  
Polymeric Materials ◽  
Term Effect ◽  
Short Term ◽  
Creep Properties ◽  
Long Term Effect ◽  
Radiation Crosslinking ◽  
Positive Effect

Radiation crosslinking of polymeric materials have placed and nowadays in the field of long-term use of loaded products. This article aims to identify the long-term effect of radiation crosslinking on micro-creep properties. The article compares the micro-creep properties of HDPE measured two years ago with the results of tests conducted under the same conditions and on the same samples now. The effect of time on the mechanical properties of the radiation crosslinked materials was demonstrated in short-term tests. These findings demonstrate the positive effect of time on the evaluated parameters.

Effect of weld structure on fracture mode of heat-temperature HP40NbTi alloy

2021 ◽  
pp. 369-379
Author(s):  
S.Yu. Kondrat'ev ◽  
M.D. Fuks ◽  
M.A. Frolov
Keyword(s):  
Mechanical Properties ◽  
Fracture Mode ◽  
Welded Joint ◽  
Structural Heterogeneity ◽  
Term Strength ◽  
Short Term ◽  
Heat Temperature ◽  
Weld Structure

The microstructure and phase composition of pipe welded joint made of HP40NbTi alloy are studied. The short-term and long-term mechanical properties of the pipe base metal and the welded joint are determined. It is shown that the structural heterogeneity of the weld and the formation of G-phase in the heat-affected zone significantly reduce the long-term strength of the alloy. The fracture mode and the role of G-phase in the cracks formation during the operation of the welded joint are studied.

Influence of Contact of Damaged Reinforced Concrete Beam and Strengthening Slab for Deformation and Resistance of Reinforced Element in the Long-Term Loading

2017 ◽  
Vol 738 ◽  
pp. 164-174
Author(s):  
Martin Krizma ◽  
Lubomir Bolha ◽  
Martin Moravcik ◽  
Matus Holubek
Keyword(s):  
Bending Moment ◽  
Reinforced Concrete Beam ◽  
Theoretical Research ◽  
Short Term ◽  
Limit States ◽  
Reinforced Beams ◽  
Repetitive Loading ◽  
Beam Strengthening ◽  
Long Term Studies

Experimental and theoretical research oriented on the influence of the time factor to limit states of damaged and then reinforced beams by the strengthening slab. In experiments there were performed two types of contact - reinforced contact (beams ST) "damaged beam / strengthening slab", respectively unreinforced contact with geometric indented modification (beams Z). Both types are based on rules EC2 for short-term load. The results are compared with short-term tests of both types of contact. In long-term studies, we have used as comparative values results for unreinforced beams (beams LTL-n). In both cases the creep coefficients are set for the following variables - total deflection a (tot), and the deflections a (sh) of shear, and the a (fl) the bending moment, the shear deformation γ, curvature ρ. All tests were carried out at the level of loading γ = 0.50. The determining of the creep coefficients was based on the experimental deformation of the fictitious truss system, which have been processed by Williot-Mohr translocation patterns. The results form the input values for the experimental elements in repetitive loading at the same level load.

scholarly journals ANALYTICAL MODELLING OF CONCRETE LONG-TERM AND SHORT-TERM STRAIN/BETONO TRUMPALAIKIŲ IR ILGALAIKIŲ DEFORMACIJŲ ANALITINIS MODELIAVIMAS

2001 ◽  
Vol 7 (1) ◽  
pp. 15-22
Author(s):  
Mindaugas Augonis
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Differential Equations ◽  
Present Model ◽  
Coarse Aggregate ◽  
Physical And Mechanical Properties ◽  
Homogeneous Material ◽  
Stress And Strain ◽  
Short Term

Concrete is not a homogeneous material. However, such an approach does not enable one to precisely determine short-term or long-term strain of concrete which consists of separate materials components with different physical and mechanical properties. Therefore, concrete should be considered a composite of coarse aggregate and mortar. Such a model enables one to take into account different properties of concrete components. The creep or shrinkage of coarse aggregate can be assumed as zero. It is enough to accept only creep or shrinkage of mortar and the present model becomes simpler. In case of a long term, load stress in matrix decreases because of relaxation. Thus, part of load passes from matrix to coarse aggregate. In order to describe such a phenomenon by integro-differential equations of creep it is necessary to know stress history for each element of matrix. It would be difficult to determine creep in this way. It is by far easier to solve macromechanical model of creep by the method of effective modulus of ageing material developed by Z. P. Bazant. This method requires only the increments of stress and strain. Figs 6 and 9–12 show that present models give similar results which are quite well-coincident with present experimental data.

scholarly journals The non-neutrality of money: a response to Dr. Humphrey

2021 ◽  
pp. 263-284
Author(s):  
Adrián O. Ravier
Keyword(s):  
Key Words ◽  
Jel Classification ◽  
Long Term Effects ◽  
Short Term ◽  
Capital Theory ◽  
Economic Cycles ◽  
Palabras Clave ◽  
True Theory ◽  
Short And Long Term

This article answers Dr. Humphrey contention on the similarities between monetarist and Austrian approaches to the neutrality of money. Monetarists at most only concentrate on short term non neutrality while Austrians base their analysis in short, medium and long term non neutrality. For the more, monetarists lack a true theory of capital that could let then understand thet even with flexible markets money would not be neutral in the short term. Key words: Economic cycles, neutrality of money, short and long term effects of money, capital theory. JEL Classification: B53, B49, D01, K13. Resumen: El presente artículo contesta la tesis del Dr. Humphrey según la cual las diferencias entre austriacos y monetaristas son ficticias pues algunos de éstos también reconocieron los efectos distorsionadores del crecimiento monetario sobre los precios relativos. El artículo demuestra que la teoría austriaca considera que el dinero no es neutral ni a corto, ni a medio ni a largo plazo y ello contrasta con el enfoque monetarista que solo reconoce la no neutralidad a corto plazo y por razones equivocadas al carecer de una verdadera teoría del capital. Palabras clave: Ciclo económico, neutralidad del dinero, corto plazo, largo plazo, teoría del capital. Clasificación JEL: B53, B49, D01, K13.

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