scholarly journals Cutting of Round Timber with Heart Rot to Structural Lumber

2021 ◽  
pp. 160-172
Author(s):  
Aleksandr S. Тoropov ◽  
◽  
Evgeniya V. Тоropova ◽  
Viktor Е. Byzov ◽  
Alexander V. Sergeevichev ◽  
...  
Keyword(s):  
Net Present Value ◽  
Large Diameter ◽  
Average Diameter ◽  
Timber Harvesting ◽  
Building Structures ◽  
Ecological Situation ◽  
Load Bearing ◽  
Softwood Lumber ◽  
Round Timber ◽  
Structural Lumber

Softwood lumber is widely used for the manufacture of load-bearing structures. However, the quality of round timber for lumber manufacturing has been deteriorating recently. The average diameter of round timber entering sawmills is constantly decreasing, and heart rot is common in large-diameter round timber. This is due to the fact that more and more conifers in the forest are being affected by heart rot. The rot infestation is related to the deterioration of the ecological situation caused by environmental pollution. As a rule, the removal of rot occurs at the stage of round timber harvesting. Therefore, during harvesting, most of the wood with heart rot continues to remain in the forest. In addition to littering the area, it continues to infect sound wood. At the same time, together with the wood affected by rot, the sound sapwood, which has good strength characteristics, is also removed. A method for processing round timber with heart rot into elements of load-bearing structures is proposed. In particular, a technological scheme for manufacturing I-beams from such timber has been developed for low-rise house construction. Corner elements are produced as a result of cutting round timber and removing heart rot by milling. The corner elements are dried in clamped state using special devices. Then they are glued together to obtain beams with a cross-section in the form of an I-beam. A set of equipment for the processing round timber with heart rot was selected. The paper presents the results of calculating the costs for organizing the production. The effectiveness of the technological project is evaluated using the method of discounted cashflows by the following indicators: net present value, profitability index, and discounted payback period. The assessment results confirm the effectiveness of the production organization of load-bearing structures made of round timber affected by heart rot. The processing of wood that remains in the forest into elements of building structures not only increases the wood reserves for construction, but also creates conditions for improving the ecological situation in forest areas. For citation: Toropov А.S., Byzov V.Е., Toropova Е.V., Sergeevichev А.V., Sazanova E.V. Cutting of Round Timber with Heart Rot to Structural Lumber. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 160–172. DOI: 10.37482/0536-1036-2021-6-160-172

scholarly journals CPT Parameters of Loess Subsoil in Lublin Area

2021 ◽  
Vol 11 (13) ◽  
pp. 6020
Author(s):  
Krzysztof Nepelski ◽  
Agnieszka Lal
Keyword(s):  
Water Content ◽  
Building Structures ◽  
Load Bearing ◽  
Engineering Research ◽  
Loess Soils ◽  
Epigenetic Processes

Loess soils were created by the wind transporting particles with later or in parallel occurred protogenetic, syngenetic and epigenetic processes. As a result, various genetic processes affected loesses strength and deformability characteristics. The aim of the study is to estimate the main CPT parameters of loess subsoil in Lublin area according to divided facies. The subsoil in the area of the Nałęczowski Plateau, where Lublin is located, consists mainly of loess from aeolian and aeolian–diluvial facies, and in the deeper parts—from aeolian–alluvial facies. Most of the results obtained for the aeolian facies at the level of qc in the range from 4.5 to 8.0 MPa indicate that these soils are a good load-bearing substrate for building structures. Cone resistances mostly at the level of 1.5–4.0 MPa for the diluvial and alluvial facies confirm that these facies constitute less favorable foundation conditions. The reduced resistance results mainly from the increased water content in ground pores. It is especially the soils of the diluvial facies that provide unfavorable foundation conditions, as they occur near the surface. Genetic processes are a very important element that should be taken into account in engineering research.

STRENGTHENING SUPPORTING COLUMNS WITH CARBON CONCRETE

2021 ◽  
Vol 95 (3) ◽  
pp. 59-67
Author(s):  
K. HOLSCHEMACHER ◽  
◽  
A.G. BULGAKOV ◽  
W. POLIENKO ◽  
◽  
...  
Keyword(s):  
Composite Material ◽  
Building Materials ◽  
Point Load ◽  
Geometrical Parameters ◽  
Building Structures ◽  
Technical School ◽  
Load Bearing ◽  
Floor Slabs ◽  
Wide Range ◽  
The Subject

Textile concrete is an innovative composite material that has been the subject of intensive research since the beginning of the 90s of the last century. After the approval of the rules and regulations on its application to strengthen floor slabs, an important step was taken towards its entry into the building materials market. Questions regarding the reinforcement of rod-shaped load-bearing elements of building structures need additional research. Despite the great potential available, the method of tying load-bearing supports and columns is still not well understood. There is a need for research on a wide range of geometric parameters and the reinforcement systems used. The Institute of Reinforced Concrete of the Higher Technical School in Leipzig tested various samples of carbon-reinforced samples in a wide range of geometrical parameters. Their goal was to assess the effect on a possible increase in the bearing capacity of carbon-reinforced columns at a concentrated point load.

The experimental study of glass multilayer columns using digital image correlation

2019 ◽  
Vol 1 (96) ◽  
pp. 32-41
Author(s):  
B. Demchyna ◽  
M. Surmai ◽  
R. Tkach
Keyword(s):  
Experimental Study ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Building Structures ◽  
Load Bearing ◽  
Regulatory Documents ◽  
Triplex Glass ◽  
Calculation Methodology ◽  
Glass Columns

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.

Coarse woody debris in mid-aged stands: abandoned agricultural versus long-term forest land

2005 ◽  
Vol 35 (6) ◽  
pp. 1502-1506 ◽  
Author(s):  
Asko Lõhmus ◽  
Piret Lõhmus
Keyword(s):  
Coarse Woody Debris ◽  
Dead Wood ◽  
No Reduction ◽  
Woody Debris ◽  
Large Diameter ◽  
Timber Harvesting ◽  
Forest Land ◽  
Successional Forests ◽  
Agricultural Areas

During the 20th century, large agricultural areas in Eastern Europe became forested after their abandonment. To explore the value of these new forests for biota, we assessed volumes of coarse woody debris (CWD) on random transects in mid-aged (40–75 years old) stands. In mixed and deciduous forests that were not forested in the 1930s, downed tree (log) volumes were about two times lower than in cutover sites. The effect on snag volume depended on site type and was generally nonsignificant. Large-diameter CWD showed similar proportions in the long-term and new forest areas, but large, well-decayed trunks tended to be less frequent in the latter. No reduction of dead wood volume was found in new pine stands, 98% of which had previously been classified as mires (bogs). Hence the origin of mid-aged successional forests had affected their CWD supply (particularly logs) to some extent, but the general scarcity of CWD all over the forest land indicated much larger (at least five-fold) losses due to timber harvesting. We conclude that naturally reforested areas should not be automatically excluded from reserve establishment or other CWD-related conservation programmes.

Integrated spatial fire and forest management planning

2010 ◽  
Vol 40 (12) ◽  
pp. 2370-2383 ◽  
Author(s):  
Mauricio A. Acuna ◽  
Cristian D. Palma ◽  
Wenbin Cui ◽  
David L. Martell ◽  
Andres Weintraub
Keyword(s):  
Forest Management ◽  
Net Present Value ◽  
Road Construction ◽  
Timber Harvest ◽  
Timber Harvesting ◽  
Harvest Scheduling ◽  
Fire Loss ◽  
Management Planning ◽  
Forest Management Planning ◽  
Access Road

Forest management planners usually treat potential fire loss estimates as exogenous parameters in their timber production planning processes. When they do so, they do not account for the fact that forest access road construction, timber harvesting, and silvicultural activities can alter a landscape’s vegetation or fuel composition, and they ignore the possibility that such activities may influence future fire losses. We develop an integrated fire and forest management planning methodology that accounts for and exploits such interactions. Our methodology is based on fire occurrence, suppression, and spread models, a fire protection value model that identifies crucial stands, the harvesting of which can have a significant influence on the spread of fires across the landscape, and a spatially explicit timber harvest scheduling model. We illustrate its use by applying it to a forest management unit in the boreal forest region of the province of Alberta in western Canada. We found that for our study area, integrated fire – forest management planning based on our methodology could result in an 8.1% increase in net present value when compared with traditional planning in which fire loss is treated as an exogenous factor.

Narrow Reinforced Concrete Slabs after their Flexural Destruction

2014 ◽  
Vol 969 ◽  
pp. 271-275 ◽  
Author(s):  
Mirosław Wieczorek
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
The Self ◽  
Concrete Slabs ◽  
Building Structures ◽  
Reinforcing Steel ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Horizontal Shift ◽  
Reinforced Concrete Slabs

In the course of the exploitation of building structures frequently situations turn up, in which the structure is not adequately used (it may, for instance, be exposed to considerably greater loads than previously been intended). In the state of an unforeseen overload of the structure, essential reserves of their load-bearing capacity may be disclosed in the case of the self-acting work as a flexible strand. The paper presents the results of investigations concerning the influence of the parameters of reinforcing steel on the mechanism of the destruction of six single-span models of narrow reinforced concrete slabs, in which a horizontal shift of the supports was not possible. The tests were carried out on narrow slabs with the dimensions 3860×480×100 mm. The results of the tests were compared with analytical calculations.

scholarly journals Influence of polysiloxane microspheres on hydrophobicity, structure and mechanical properties of paper materials

Cellulose ◽  
2021 ◽  
Author(s):  
Piotr Pospiech ◽  
Konrad Olejnik ◽  
Urszula Mizerska ◽  
Joanna Zakrzewska
Keyword(s):  
Mechanical Properties ◽  
Large Diameter ◽  
Small Diameter ◽  
Average Diameter ◽  
Barrier Properties ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Material Structure ◽  
Liquid Penetration ◽  
The Impact

Abstract The aim of the study was to investigate the impact of three types of polysiloxane microspheres on the barrier properties, structure and mechanical properties of paper. An influence of new silicon filler on properties of cellulose paper sheet was analyzed. Polysiloxane microspheres were used as an additive introduced into the network of cellulosic fibers in order to obtain new functional properties of the paper. The following types of microspheres were used in the research: M1 hydrophilic of average diameter 23.5 µm, M2 hydrophobic of average diameter 3.1 µm and M3 hydrophobic of average diameter 23.5 µm. The obtained handsheets were analyzed for changes in apparent density, roughness, tensile strength, bursting strength, and tear resistance. Wettability and resistance to liquid were characterized by contact angle measurement, penetration dynamics analysis  and uniformity of liquid penetration measured using an extended liquid penetration analyser. It was found that the presence of M2 (small diameter) microspheres improved significantly the paper’s hydrophobicity without changing the mechanical properties. The addition of M1 and M3 (large diameter) microspheres decreased the mechanical properties of the paper samples and did not improve their hydrophobicity. However, M1 microspheres resulted in increased uniformity of liquid penetration through the paper structure. The presented studies also show that it is possible to obtain paper with high hydrophobic properties only through the filling application when polysiloxane microspheres are used for this purpose. The results also indicate that it is not necessary to hydrophobize the entire material structure in order to achieve its high hydrophobicity. Graphic abstract

scholarly journals Justification of the forces required for leveling ends of floating packaged rafting units

2021 ◽  
pp. 165-178
Author(s):  
И.А. Песков ◽  
С.В. Посыпанов
Keyword(s):  
Shape Factor ◽  
Granular Media ◽  
Analytical Formula ◽  
Theoretical Method ◽  
Average Diameter ◽  
Two Factors ◽  
Calculation Results ◽  
The Media ◽  
Different Characteristics ◽  
Round Timber

При реализации концепции, обеспечивающей экономическую доступность удаленных лесных ресурсов, предусматривается сплотка малогабаритных пакетов круглых лесоматериалов в двухъярусные единицы в пунктах выхода с мелководных участков рек на глубоководные. Указанная сплотка предполагается в специальных устройствах, где предусматривается, в частности, торцевание сплоточных единиц с целью повышения экономических показателей дальнейшей транспортировки и надежности сохранения их целостности. Для обоснования параметров устройства нужна информация о требуемых усилиях для торцевания плавающих пакетов и двухярусных единиц из них. Установлено, что для ее получения нужны дополнительные исследования. Очевидна целесообразность общей методологии для двухъярусных единиц и составляющих их пакетов, с которых и следует начать исследования. С целью получения зависимости для расчета усилия, необходимого для торцевания плавающих пакетов, использовали теоретический метод, базирующийся на эластиковой теории. При этом плавающий пакет рассматривали как гибкую оболочку, заполненную двумя видами сыпучей среды с разным объемным весом. Граница сред проходит по поверхности воды. Линия обвязки, то есть гибкой оболочки представляет собой комбинацию фрагментов двух эластик с разными характеристиками. Используя параметрические уравнения, описывающие форму эластик, и зависимости для определения давлений в сыпучих средах, получили искомую аналитическую зависимость и ее упрощенный вариант для практических расчетов. Результаты расчетов по предложенной формуле превышают результаты, вычисленные по формуле, полученной ранее по другому алгоритму действий без учета давления обвязок, на 70% при коэффициенте формы пакета 1,5, то есть при сильном давлении обвязок и примерно на 10% – при коэффициенте 2,5, то есть слабом их давлении. Это позволяет считать результаты исследования достоверными, применение использованной методики для соответствующего исследования двухъярусным единиц – целесообразным. Установили, что при фиксированной плотности лесоматериалов наиболее существенно влияют на усилие торцевания изменения отношения высоты пакета к среднему диаметру лесоматериалов, его коэффициента формы и объема. Влияние первых двух факторов в аналитической формуле учитывается множителем, величину которого в практических расчетах можно определить по предложенным графикам или аппроксимирующим зависимостям. When implementing the concept that ensures the economic accessibility of remote forest resources, it is envisaged to raft small-sized packages of round timber into bilevel units at the points of exit from shallow-water sections of rivers to deep-water ones. The specified raft is assumed in special devices, which provide the leveling ends of rafting units to increase the economic indicators of further transportation and the reliability of maintaining integrity. To substantiate the parameters of the device, information is needed on the required forces for leveling ends of floating packages and bilevel units of them. It was found that to obtain it requires additional research. The expediency of a common methodology for bilevel units and their constituent packages is obvious, from which research should be started. To obtain the dependence for calculating the force required for leveling ends of the floating packages, a theoretical method based on the elastic theory was used. In this case, the floating package was considered as a flexible shell filled with two types of granular media with different bulk density. The boundary of the media runs along the surface of the water. The strapping line, that is, the flexible casing, is a combination of fragments of two elastics with different characteristics. Using parametric equations describing the shape of elastic and dependences for determining pressures in bulk media, we obtained the required analytical dependence and its simplified version for practical calculations. The calculation results according to the proposed formula exceed the results calculated according to the formula obtained earlier using another algorithm of actions without considering the pressure of the straps by 70% with a package shape factor of 1.5, that is, with a strong pressure of the straps and by about 10% – with a coefficient of 2.5, that is, their weak pressure. This allows us to consider the results of the study reliable, the use of the methodology used for the corresponding study of bilevel units is expedient. It was found that at a fixed density of timber, the most significant effect on the force of leveling ends is changes in the ratio of the height of the package to the average diameter of timber, its shape factor and volume. The influence of the first two factors in the analytical formula is considered by a factor, the value of which in practical calculations can be determined from the proposed graphs or approximating dependences.

scholarly journals Das Potenzial der Totholzakkumulation im deutschen Wald | Potential of deadwood accumulation in German forests

2010 ◽  
Vol 161 (5) ◽  
pp. 171-180 ◽  
Author(s):  
Franz Kroiher ◽  
Katja Oehmichen
Keyword(s):  
Tree Species ◽  
Forest Inventory ◽  
Decay Constant ◽  
Dead Wood ◽  
Large Diameter ◽  
Timber Harvesting ◽  
National Forest Inventory ◽  
Time Span ◽  
National Forest

Deadwood is an important part of the forest ecosystem. The quantity available depends on the rates of accumulation and of decomposition. A comprehensive pool of data regarding the deadwood stock for Germany is collected by the German national forest inventory. Moreover, the Projection Modelling of Forest Development and Timber Harvesting Potential (WEHAM) adds other important parameters such as growth rates and potential roundwood availability. Using this data, scenarios for the accumulation of deadwood were developed. For the calculation of deadwood decomposition, independent of tree species, a decay constant k = 0.054 was derived for the whole of Germany. The study shows that a long-term stop in timber harvesting in Germany, assuming the proportions of different tree species remained constant, would lead to a saturation of deadwood with a total of 184 m3/ha. If the German forest presented a natural composition of tree species, a deadwood stock of 150 m3/ha at most could be accumulated. Based on these scenarios, rates of accumulation of total dead-wood and of deadwood of large diameter can be calculated taking into account the deadwood stock levels desired and the time span involved. It has been shown that 7.3% of the WEHAM potential roundwood availability must remain in the forest per year if the quantity of deadwood is to be maintained at 11.5 m3/ha. If an increase in the accumulation of deadwood is to be aimed for, the annual input rate together with the desired deadwood stocks are increasingly influenced by the time span involved. Thus shorter time spans with greater stocks of deadwood to be achieved make it possible to approach the WEHAM potential roundwood availability. The results presented in this paper should assist in decision-making concerning stocks of deadwood to be aimed for in the forest and, in the future, serve as a basis for the selection, evaluation and discussion of quantities of dead-wood to be achieved.

Sign in / Sign up

Export Citation Format

Share Document