This paper reports the full-scale experimental measurements of temperature distribution over the surfaces of bridges' steel-concrete beams under the influence of positive and negative ambient temperatures. It has been established that the temperature is distributed unevenly along the vertical direction of a bridge's steel-concrete beam. It was found that the metal beam accepted higher temperature values. The maximum registered temperature difference between a metal beam and a reinforced concrete slab at positive ambient temperatures was +9.0 °C, and the minimum temperature difference was −2.1 °C. The mathematical models for calculating a temperature field and a thermally strained state of bridges' steel-concrete beams under the influence of variable climatic temperature changes in the environment have been improved, taking into consideration the uneven temperature distribution across a bridge's reinforced concrete beam. The possibility has been established to consider a one-dimensional problem or to apply the three-dimensional estimated problem schemes as the estimation schemes for determining the thermo-elastic state of reinforced concrete bridges. The temperature field and the stressed state of bridges' reinforced concrete beams were determined. It was found that the maximum stresses arise at the place where a metal beam meets a reinforced concrete slab. These stresses amount to 73.4 MPa at positive ambient temperatures, and 69.3 MPa at negative ambient temperatures. The amount of stresses is up to 35 % of the permissible stress values. The overall stressed-strained state of a bridge's reinforced concrete beams should be assessed at the joint action of temperature-induced climatic influences and loads from moving vehicles
The nature of the cyclicity phenomenon and life cycle in the development of urbanized systems is outlined. The paper defines the extent to which the components determine the processes peculiar to cyclical development. To generate the hierarchy of factors causing the cyclicity in urban development, uniqueness of origin, and patterns of urban cycle development, the model of space five-dimensionality and historical context of urban development were used. The space five-dimensionality model is conceptual, its substantiation and interpretation considering the specific tasks contribute to the adjustment of the system condition, its evaluation, and specification of development directions based on the methodological platform of the system approach. The approach that stipulates the identification of urban space elements and their interaction with the view to search for characteristics consistency and compatibility is the ground for substantiation of the urban development cyclicity. The cyclicity phenomenon and life cycle in the development of urbanized systems are analyzed on the basis of the selected examples from Lviv’s history and present. The need for and methods to consider cyclicity in substantiation of architectural-urbanistic decisions are outlined in Lviv’s urban development. The following most important urban issues are emphasized: development of the Poltva valley; lack of system nature in reserving the areas in the suburban zone; aggravated transport problems caused by ignoring the general plan requirements and provisions; lack of system housing policy; engineering-technological problems and suspension of industrial development in the city. General requirements to organization and development of Lviv urban space considering the cyclicity and positive change in current trends are suggested.
To determine the tendencies of reflection of the socioeconomic and spatial changes of the post-Soviet period in the minds of Lviv residents, to outline the factors influencing the transformations that are taking place. Historical development of Lviv – a multifunctional city with almost 800 years of history, cultural and educational center of Ukraine, was artificially transformed into an industrial center in the Soviet period. Transformations of Lviv image of the post-Soviet period were investigated on the basis of official statistics, analysis of town-planning projects and selective urban inventory. The actions of the authorities in influencing the changes in the image of the city are analyzed on the basis of approved strategic documents of development, as well as the activities of local self-government bodies. During the last three decades, Lviv has lost its competitiveness, and there is a decrease in population due to both natural growth and migration; increasing concentration of people and business functions in its central part; problems of transport and preservation of the historical environment of the city are aggravated; tourist anthropogression on the city is growing and tourist erosion is increasing. Assessments of an image change in residents’ perceptions are analyzed by comparing their own research and questionnaires. 200 surveys were conducted, the results of which are as follows: 1) An increase in the disorder of urban life and an increase in its intensity were recorded; 2) c the spatial image of the city is associated mainly with the growing importance of the old part of the city (localization of more and more services); 3) post-industrial territories are treated as places where the crisis of the city is visible; 4) the symbols of the city are unchanged, new ones are not named; 5) areas of high attractiveness in functional, social and aesthetic relations are distinguished, as well as low attractiveness spaces. The spatial changes of Lviv in the post-Soviet period are generally assessed as critical. The residents point out that Lviv does not create a sacred image anymore, it loses the aura of its intellectual and cultural center; the center is not attractive to architecture and history, but to restaurants that have transformed former art salons and bookstores; architectural identity and uniqueness are lost; space polarization is deepening (expensive commercial housing adjacent to neglected public spaces); commerce with a devastating excitement about the existing spatial order burst into the historical environment. The lack of a unified vision of city development and management of urban planning processes «in manual mode» causes chaotic and unsystematic changes that destroy the spatial structure, principles of city development and causes irreparable mistakes in its construction then copy it into the registration web field.
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