scholarly journals Study of the stress-strain state of reinforced geosynthetic material or the foundation of the bored foundation of the bridge

2019 ◽  
Vol 6 (4) ◽  
Author(s):  
Sergey Kudryavtsev ◽  
Tatiana Valtseva ◽  
Vyacheslav Shemyakin ◽  
Yuliya Bugunova ◽  
Zhanna Kotenko
Keyword(s):  
Bearing Capacity ◽  
Building Materials ◽  
Nonlinear Models ◽  
Far East ◽  
Soil Mass ◽  
Operational Reliability ◽  
Climatic Conditions ◽  
Stable Operation ◽  
Rational Solutions ◽  
High Level

The building of constructions in northern regions of the Far East is always connected with a high degree of seasonal freezing risk. This especially refers to a line transport structures which require a high level of reliability and responsibility. Such structures should provide permissible deformability and bearing capacity of the bases when exposed to promising moving loads in difficult geological and climatic conditions. The article discusses the study of the foundations of bored foundations of bridges using methods of mathematical modeling and geosynthetic materials. The study used standard and numerical calculation methods to determine the rational parameters of structural elements and the degree of their operational reliability and durability. In determining the behavior of structures as a whole with the joint interaction of their individual elements with each other, nonlinear models of the soil of the base of the structures were used. Numerical modeling of bored foundations in an elasto-plastic soil mass allowed us to develop effective structural solutions to reduce the deformability of the bridge and increase the bearing capacity of the pile foundation due to reinforcing measures during the construction of the grillage and the creation of rational parameters of the structure as a whole. One of the rational solutions for the main issues which is connected with a construction of facilities in the areas with complex geological and climatic conditions is reasonable usage of modern geosynthetic material properties. Such materials are capable of providing long-term stable operation of facilities made of local building materials. So, the properties of such geosynthetics materials must fully comply with the demands of conditions of their work in the structures and provide a long lifespan as well as high quality.

scholarly journals The construction of buildings and structures in extremally climatic conditions: features of the organization of works and used materials

2018 ◽  
Vol 5 (4) ◽  
Author(s):  
Alexandra Funk
Keyword(s):  
Building Materials ◽  
Construction Materials ◽  
Climatic Conditions ◽  
The Arctic ◽  
Deep Foundations ◽  
Construction Technology ◽  
Destructive Effect ◽  
Environment Temperature ◽  
Materials Used ◽  
High Level

The author considers the features of the organization of works and construction materials used in the construction of buildings and structures in extreme climatic conditions. Also, the features of the influence of climatic conditions on the quality and basic properties of building materials, construction technology, etc. the High level of complexity of the organization of construction works, in particular, in the Arctic, caused by the aggressive environment, temperature changes (especially low in winter), land work is complicated by permafrost. This especially affects deep foundations, pipes, basement panels, piles. The author notes that the destruction of such objects is affected by the saturation of their ground water with its circulation from the bottom up. Also has a destructive effect and hydrostatic pressure, sea, river and lake water, next to which the construction site is being built. The author comes to the conclusion that the construction of buildings and structures, taking into account the construction area, which is characterized by certain meteorological and climatic conditions, has certain features, respectively, to increase the efficiency of construction in extreme climatic conditions-is a complex multi-faceted task of the organization and technology of construction production, designed to improve the quality of construction, reduce the timing of its implementation, labor and cost of work.

scholarly journals Parametric bootstrap estimators for hybrid inference in forest inventories

2017 ◽  
Vol 91 (3) ◽  
pp. 354-365 ◽  
Author(s):  
Mathieu Fortin ◽  
Rubén Manso ◽  
Robert Schneider
Keyword(s):  
Multiple Imputation ◽  
Nonlinear Models ◽  
Parametric Bootstrap ◽  
Simulation Studies ◽  
Variance Estimator ◽  
Resampling Methods ◽  
Forest Inventories ◽  
Point Estimator ◽  
Complex Models ◽  
High Level

Abstract In forestry, the variable of interest is not always directly available from forest inventories. Consequently, practitioners have to rely on models to obtain predictions of this variable of interest. This context leads to hybrid inference, which is based on both the probability design and the model. Unfortunately, the current analytical hybrid estimators for the variance of the point estimator are mainly based on linear or nonlinear models and their use is limited when the model reaches a high level of complexity. An alternative consists of using a variance estimator based on resampling methods (Rubin, D. B. (1987). Multiple imputation for nonresponse surveys. John Wiley & Sons, Hoboken, New Jersey, USA). However, it turns out that a parametric bootstrap (BS) estimator of the variance can be biased in contexts of hybrid inference. In this study, we designed and tested a corrected BS estimator for the variance of the point estimator, which can easily be implemented as long as all of the stochastic components of the model can be properly simulated. Like previous estimators, this corrected variance estimator also makes it possible to distinguish the contribution of the sampling and the model to the variance of the point estimator. The results of three simulation studies of increasing complexity showed no evidence of bias for this corrected variance estimator, which clearly outperformed the BS variance estimator used in previous studies. Since the implementation of this corrected variance estimator is not much more complicated, we recommend its use in contexts of hybrid inference based on complex models.

Ruling out Change: Institutional Impediments to Transfer of Technology in Ship Building and Design in the Far East

Itinerario ◽  
1995 ◽  
Vol 19 (3) ◽  
pp. 142-152
Author(s):  
Bao Leshi
Keyword(s):  
Coastal Waters ◽  
Building Materials ◽  
Far East ◽  
Local Conditions ◽  
Ship Building ◽  
The Past ◽  
Transfer Of Technology ◽  
Construction Techniques ◽  
Different Types ◽  
Technological Tradition

In the Chinese technological tradition, no sector, apart from that of agriculture, is as rich in original ideas as naval architecture. Over the past three millennia, hundreds of different types of craft have been developed for use on China's shallow lakes, on its fast flowing rivers and along its often stormy coastal waters. Each type was developed for specific use as a means of transportation, and would seem to represent the ultimate answer to the challenges posed by local conditions. Ultimate answer, that is, within the limitations of the traditional building materials with which these boats were constructed and fitted out. Nor was ingenuity confined to construction techniques.

Bearing Capacity Characteristic of Unsaturated Granular Soils

2011 ◽  
Vol 261-263 ◽  
pp. 989-993 ◽  
Author(s):  
Anuchit Uchaipichat ◽  
Ekachai Man Koksung
Keyword(s):  
Bearing Capacity ◽  
Matric Suction ◽  
Ultimate Bearing Capacity ◽  
Experimental Program ◽  
Granular Soils ◽  
Test Results ◽  
High Level ◽  
Unsaturated Granular Soils ◽  
Capacity Characteristic

An experimental program of laboratory bearing tests was performed to characterize the bearing capacity of foundation on unsaturated granular soils. All tests were performed by pushing a circular rod on the surface of compacted sand specimens with different values of matric suction until failure. The test results show an increase in ultimate bearing capacity with increasing matric suction at low suction value but a decrease in that at high level of suction. The comparisons between the test results and simulations using the expressions proposed in this paper are presented and discussed. Good agreements are achieved for all testing values of suction.

Development of a numerical approach to assess the effect of coupled heat and moisture transfer on energy consumption of residential buildings in Moroccan context

2021 ◽  
pp. 174425912110560
Author(s):  
Yassine Chbani Idrissi ◽  
Rafik Belarbi ◽  
Mohammed Yacine Ferroukhi ◽  
M’barek Feddaoui ◽  
Driss Agliz
Keyword(s):  
Energy Consumption ◽  
Building Materials ◽  
Moisture Transfer ◽  
Residential Buildings ◽  
Building Design ◽  
Energy Performance ◽  
Climatic Conditions ◽  
Heat And Moisture Transfer ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture

Hygrothermal properties of building materials, climatic conditions and energy performance are interrelated and have to be considered simultaneously as part of an optimised building design. In this paper, a new approach to evaluate the energy consumption of residential buildings in Morocco is presented. This approach is based on the effect of coupled heat and moisture transfer in typical residential buildings and on their responses to the varied climatic conditions encountered in the country. This approach allows us to evaluate with better accuracy the response of building energy performance and the indoor comfort of building occupants. Annual energy consumption, cooling and heating energy requirements were estimated considering the six climatic zones of Morocco. Based on the results, terms related to coupled heat and moisture transfer can effectively correct the existing energy consumption calculations of the six zones of Morocco, which currently do not consider energy consumption due to coupled heat and moisture transfer.

A PROMISING ASSORTMENT OF TREES AND SHRUBS FOR LANDSCAPING IN VOLGOGRAD CITY

2021 ◽  
pp. 5-18
Author(s):  
E.N. Tyukhtina ◽  
Keyword(s):  
Negative Impact ◽  
Ornamental Plants ◽  
Botanical Garden ◽  
Climatic Conditions ◽  
Green Spaces ◽  
Ecological Situation ◽  
High Concentration ◽  
High Level ◽  
The City ◽  
Trees And Shrubs

The article deals with one of the most relevant topics of the modern city and ecology - the problem of landscaping in Volgograd. The city is characterized by an industrial urbanism, with a high concentration of population, saturation of production facilities and vehicles, which contributes to a high level of negative impact on the environment. The pace of greening of the city lags behind the pace of construction of the residential sector, and the existing green spaces do not meet the sanitary and hygienic, aesthetic requirements. The prospects of this problem are determined, the existing green spaces are considered, data on the climatic conditions of the city and the ecological situation are given. Improvement in the field of landscaping is associated with the scientifically sound placement of green spaces, taking into account all the factors that affect the growth and development of plants in the urban environment. Unfortunately, due to the uneven distribution of the assortment of trees and shrubs, the species composition of the central streets and squares of the city is extremely poor. The study focuses on the role of the botanical garden in urban landscaping and aims to create recommendations for the sorting of tree and shrub plants for urban landscaping. As a result of the analysis of the assortment of ornamental plants of the open ground of the botanical garden, the article proposed species and varieties of woody and shrubby plants that have passed the introduction tests for more than 5-10 years. Recommendations for sorting are aimed at improving the ecological situation of the city and greening the recreation areas of citizens. The proposed list of tree and shrub species cannot fully solve the problem of greening the city, but it will help to significantly enrich the composition of tree and shrub plants.

scholarly journals Chronology of Lake El'gygytgyn sediments – a combined magnetostratigraphic, palaeoclimatic and orbital tuning study based on multi-parameter analyses

2013 ◽  
Vol 9 (6) ◽  
pp. 2413-2432 ◽  
Author(s):  
N. R. Nowaczyk ◽  
E. M. Haltia ◽  
D. Ulbricht ◽  
V. Wennrich ◽  
M. A. Sauerbrey ◽  
...  
Keyword(s):  
Global Climate ◽  
Far East ◽  
Climatic Conditions ◽  
Sedimentation Rates ◽  
Scientific Drilling ◽  
Lake El’Gygytgyn ◽  
Age Model ◽  
Orbital Tuning ◽  
Lake Floor ◽  
The Impact

Abstract. A 318-metre-long sedimentary profile drilled by the International Continental Scientific Drilling Program (ICDP) at Site 5011-1 in Lake El'gygytgyn, Far East Russian Arctic, has been analysed for its sedimentologic response to global climate modes by chronostratigraphic methods. The 12 km wide lake is sited off-centre in an 18 km large crater that was created by the impact of a meteorite 3.58 Ma ago. Since then sediments have been continuously deposited. For establishing their chronology, major reversals of the earth's magnetic field provided initial tie points for the age model, confirming that the impact occurred in the earliest geomagnetic Gauss chron. Various stratigraphic parameters, reflecting redox conditions at the lake floor and climatic conditions in the catchment were tuned synchronously to Northern Hemisphere insolation variations and the marine oxygen isotope stack, respectively. Thus, a robust age model comprising more than 600 tie points could be defined. It could be shown that deposition of sediments in Lake El'gygytgyn occurred in concert with global climatic cycles. The upper ~160 m of sediments represent the past 3.3 Ma, equivalent to sedimentation rates of 4 to 5 cm ka−1, whereas the lower 160 m represent just the first 0.3 Ma after the impact, equivalent to sedimentation rates in the order of 45 cm ka−1. This study also provides orbitally tuned ages for a total of 8 tephras deposited in Lake El'gygytgyn.

scholarly journals Concrete based on sulfur binder being modified with inorganic additives

2018 ◽  
Vol 212 ◽  
pp. 01013
Author(s):  
Vadim Balabanov ◽  
Victor Baryshok ◽  
Nikita Epishkin
Keyword(s):  
Frost Resistance ◽  
Building Materials ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Strength Properties ◽  
Climatic Conditions ◽  
Freezing And Thawing ◽  
Concrete Mixtures ◽  
Irkutsk Region ◽  
Water Saturated

The sharply continental climate of the Irkutsk region is characterized by wide temperature intervals throughout the year. The repeated cyclicity of freezing and thawing of building materials in the water-saturated state influences the change in technical characteristics and the durability of concrete products and structures. The concrete products’ features in such climatic conditions create the need for the production of concretes with improved indicators of physical and mechanical properties. The effect of modifying additives on the technological characteristics of sulfur concrete is established. The effect of all elements of sulfur concrete on its strength and frost resistance. The composition of sulfuric concrete is obtained, which meets all the requirements and also has high strength and increased frost resistance. Formulations with a certain ratio of structural sulfuric concrete mixtures were developed. As a result of the use of technical sulfur in the composition of concrete products, the problem of utilizing annually accumulating reserves of technical sulfur is partially solved. The strength properties of sulfuric concretes easily compete with high-quality brands of concrete, special types of concretes that have in their composition additives.

scholarly journals Effect of Pile Spacing on Group Efficiency in Gypseous Soil

2019 ◽  
Vol 5 (2) ◽  
pp. 373 ◽  
Author(s):  
Bilal Jabbar Noman ◽  
Safaa H. Abd-Awn ◽  
Hassan O. Abbas
Keyword(s):  
Bearing Capacity ◽  
Load Condition ◽  
Soil Mass ◽  
Deep Foundation ◽  
Collapsible Soil ◽  
Floating Pile ◽  
Group Efficiency ◽  
Gypsum Content ◽  
Group Pile ◽  
Gypseous Soil

As a matter of fact, the gypseous soil is usually considered as collapsible soil, such type of soil illustrates high resistance to settlement and high bearing capacity when it is dry, but it loses these characteristics when it is inundated and collapses excessively because of the sudden decrease in the volume of the surrounding soil mass. It is founded in the arid and semi-arid regions of the world in Asia, South Asia (Iraq, Syria, Jordan, Yemen, and Iran), North Africa, North America, moreover, it covers more than (31%) of the surface area in Iraq. Gypseous soil is one of the most difficult problems facing the process of building any project because of the difficulty of preventing leakage of water to the soil in practice. Deep foundation (piles) are one of the most common types used in collapsible soils which penetrating problematic soil layers and reaching more hard ones (end bearing piles) or transfers loads depending on skin friction (floating pile). The current work is directed to study the behavior of single and group driven pile of square pattern (4 piles) in case of floating pile (friction pile) with different spacing (2D, 4D, 6D) and length to diameter (L/D) ratio of (20) in this special medium dense soil (gypsum content 30% and 61%) under axial load condition. The investigation was carried out to measure the soil collapse before and after inundation. The results showed that the group efficiency for spacing 2D is less than one while for spacing 4D and 6D are more than that value. In addition, the spacing 4D was more efficient to carry 4 group pile in both dry and soaked cases, in addition, the result showed a high reduction in the bearing capacity at inundation state of group pile of (82% in gypsum content 30%) and ( 87% in gypsum content 61%) with respect to dry state.

scholarly journals IMPROVING THE EFFICIENCY OF FIBRE CONCRETE PRODUCTION

2020 ◽  
pp. 4-9
Author(s):  
V. Nelyubova ◽  
V. Babaev ◽  
Nataliya Alfimova ◽  
S. Usikov ◽  
O. Masanin
Keyword(s):  
Building Materials ◽  
Production Efficiency ◽  
Raw Materials ◽  
Basalt Fiber ◽  
Operational Reliability ◽  
Fiber Reinforced Concrete ◽  
Technological Parameters ◽  
Optimal Method ◽  
Physicomechanical Characteristics ◽  
Concrete Production

fiber concrete is one of the types of effective building materials that ensure the operational reliability of structures due to a set of unique properties. However, the maximum physicomechanical characteristics of this type of products are achieved only if the fiber is evenly distributed in the concrete matrix and the optimum ratio of raw materials is reached. In this connection, the aim of the work was to increase the production efficiency of fiber-reinforced concrete by optimizing the formulation and technological parameters of its manufacture. The optimal method of introducing the fiber into the concrete mix and the type of superplasticizer were previously determined, which allowed ensuring the maximum physicomechanical characteristics of the products. Optimization of prescription parameters was carried out using the method of mathematical planning of the experiment, where the amount of cement, superplasticizer and basalt fiber were varied. After processing the results, the dependences of the compressive strength on variable factors were obtained, which would allow to select the optimal dosages of raw materials for given mechanical characteristics of the products.

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