Experimental Study on Loading Capacity of Glued-Laminated Timber Arches Subjected to Vertical Concentrated Loads

Glued-laminated timber arches are widely used in gymnasiums, bridges, and roof trusses. However, studies on their mechanical behaviours and design methods are still insufficient. This paper investigates the in-plane loading capacity of circular glued-laminated timber arches made of Douglas fir. Experiments were conducted on four timber-arch models with different rise-to-span ratios under concentrated loads at mid-span and quarter-point locations. The structural responses, failure modes, and loading capacity of the timber arch specimens were obtained. The results show that the timber arches presented symmetric and antisymmetric deformation under mid-point and quarter-point loading conditions, respectively. The downward shifting of the neutral axis of the cross section was observed under mid-point loading condition, which contributes to higher loading capacity compared to that under quarter-point loading condition. The loading condition significantly affects the ultimate loads and the strain distribution in the cross section. Based on the design formula in current standards for timber structures, an equivalent beam-column method was introduced to estimate the loading capacity of the laminated timber arches under vertical concentrated loads. The moment amplification factor in the formula was compared and discussed, and the value provided in the National Design Specification for Wood Construction was recommended with acceptable accuracy.

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VALUATION OF DURABILITY OF ROD PILLARS OF THE SLOPY RESCUING DEVICE

Bulletin of Lviv State University of Life Safety ◽

10.32447/20784643.21.2020.07 ◽

2020 ◽

Vol 21 ◽

pp. 67-72

Author(s):

L. Dzyuba ◽

Kh. Lishchynska ◽

A. Somyk

Keyword(s):

Cross Section ◽

Emergency Response ◽

Horizontal Plane ◽

Loading Capacity ◽

Structural Elements ◽

The Third ◽

Material Type ◽

First Case ◽

The Cross ◽

Straight Rod

The need for special saving devices arises during emergency response. Such situations are connected with rescuing of people or animals from deep narrow holes or even from under blockages of constructions. By using the saving devices the cargo raising on a certain height is possible if other ways of delivery are absent. Main structural elements of saving devices are three rod pillars. Top ends of rods are connected in a mounting knot. Often the saving device is equipped with the winch. The winch could be fasten to one of the rod pillars or have individual placing. Rescuing devices differ in a type of a rod design (straight or a slopy plane), loading capacity, rods production material, type of rods connection, a possibility of using on slopes with pillars location in the different planes, modifications of winches, compactness during transportation. There is a big variety of rescuing devices, however in the market of Ukraine offer mostly straight rod rescuing devices. Therefore there is a need for creation of design and durability checking of the slopy rod rescuing device which could be applied to carrying out rescue operations from bridges, buildings and other constructions. In this work it is performed an estimation of durability of a design of the slopy rod rescuing device. It is considered three cases of the support pillars placement. The first case is when pillars of the slopy rescuing device are placed in one horizontal plane. The second case - the longest rod pillar is placed on a ledge. The third case - two shorter rod pillars are placed on a ledge. For each of these cases it is established a type of deformation of rods of the saving device. Construction rods are stretching or compression during work are and loaded with longitudinal forces. From the stretching durability condition the cross section of steel rods is picked up.

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A New Approach to the Demonstration of Oxidase-Localization Using Tannic Acid Or Catechin

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073933 ◽

1973 ◽

Vol 31 ◽

pp. 698-699

Author(s):

V. Mizuhira ◽

Y. Futaesaku

Keyword(s):

Cross Section ◽

Tannic Acid ◽

Elastic Fiber ◽

The Other ◽

New Approach ◽

Tissue Block ◽

Active Reaction ◽

The Cross

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.

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Energy Distribution in Electron Beams

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096096 ◽

1972 ◽

Vol 30 ◽

pp. 568-569

Author(s):

Tamotsu Ohno

Keyword(s):

Electron Beam ◽

Energy Distribution ◽

Cross Section ◽

Integral Curve ◽

Electron Beams ◽

Electron Gun ◽

Angular Divergence ◽

Apparent Increase ◽

Integral Width ◽

The Cross

The energy distribution in an electron; beam from an electron gun provided with a biased Wehnelt cylinder was measured by a retarding potential analyser. All the measurements were carried out with a beam of small angular divergence (<3xl0-4 rad) to eliminate the apparent increase of energy width as pointed out by Ichinokawa.The cross section of the beam from a gun with a tungsten hairpin cathode varies as shown in Fig.1a with the bias voltage Vg. The central part of the beam was analysed. An example of the integral curve as well as the energy spectrum is shown in Fig.2. The integral width of the spectrum ΔEi varies with Vg as shown in Fig.1b The width ΔEi is smaller than the Maxwellian width near the cut-off. As |Vg| is decreased, ΔEi increases beyond the Maxwellian width, reaches a maximum and then decreases. Note that the cross section of the beam enlarges with decreasing |Vg|.

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Research in the cross-section of community psychology and global climate change: A call for action

PsycEXTRA Dataset ◽

10.1037/e628592012-083 ◽

2009 ◽

Author(s):

Marci Culley ◽

Holly Angelique ◽

Courte Voorhees ◽

Brian John Bishop ◽

Peta Louise Dzidic ◽

...

Keyword(s):

Climate Change ◽

Cross Section ◽

Global Climate Change ◽

Community Psychology ◽

Global Climate ◽

The Cross

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Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2019.01.22-30 ◽

2019 ◽

pp. 22-30

Keyword(s):

Cross Section ◽

Cross Sections ◽

Applied Load ◽

Experimental Studies ◽

Strength Properties ◽

Research Topic ◽

Normative Values ◽

Laminated Glass ◽

The Cross ◽

Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

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