Резюме. Цель. Целью данной статьи является анализ возможностей, предоставляемых исследователям различными расчетными методами (в первую очередь -численными) для теоретического исследования напряженно-деформированного состояния (НДС) сложных многопроёмных вертикальных несущих систем. Метод. Раскрыта принципиальная сущность метода конечных разностей (сеток) и метода конечных элементов, описаны их преимущества и недостатки при решении плоской задачи теории упругости, в частности -при расчете НДС панельно-рамных конструкций, объединенных в единую вертикальную многосвязную систему. Результат. Изложенные в статье материалы позволяют оптимизировать методику теоретического анализа НДС сложных многосвязных систем с учетом имеющихся в наличии средств вычислительной техники и лицензионных пакетов программ автоматизированного расчета строительных конструкций. Вывод. Проведенный авторами анализ показывает, что при наличии достаточно мощных ЭВМ наиболее универсальным и эффективным является метод конечных элементов, с использованием которого составлено большое число программных пакетов, позволяющих исследовать НДС любых конструкций, сложных по своей форме, топологии, характеру нагружения и т.п. Ключевые слова: плоская задача теории упругости, метод сеток, метод конечных элементов, многосвязные панельно-рамные системы, рамная аналогия, бигармоническое уравнение, разностные аналоги, напряженно-деформированное состояние

In this article structural concepts peculiarities of bridge structures for mountain conditions were analyzed. It is noted that the mountainous terrain is characterized not only by a complex broken rock but also by the course of earthquakes and their genetic varieties: landslides, avalanches, rockfalls, etc. It is also noted that the interaction of the plain bridge and the environment is one-sided, while mountainous bridges themselves are negatively influenced by the mountainous environment. The Republic of Dagestan territory is considered an example of mountainous terrain. The linking bridge structures problem to various mountainous terrain regions is investigated here. The peculiarity of the mountain rivers and bridge crossings interaction is noted in this paper, as well as the influence of rivers on the constructive justification of the mountain bridges solutions. The possibility of using cascade systems for regulating the mountain rivers water regime for the rational bridge crossings design with several holes is considered. Various options for the bridge crossings placement relative to mountain rivers are given as well as described their peculiarities. Current support parts and expansion joints are considered and analyzed from the mountain bridge use on structures suitability point of view. The necessity of using seismic-insulating expansion joints and their influence on the conditions of vehicles passing through the bridge structure during an earthquake is substantiated here. The problem of using road pavements on mountain bridge structures is noted, the most common road pavements designs are described and analyzed. The concepts of the «ideal» bridge and their applied significance in relation to mountainous terrain are presented. The constructive and technological solutions considered within the framework of this article will improve the bridge structure’s efficiency in mountainous conditions.

The manual, taking into account the modern requirements of medical science, discusses the main issues of the organization of sanitary and hygienic control and assessment of the impact of environmental and hygienic factors on the health of the population in the sections «Air environment as an environmental factor», «water Hygiene and water supply», «Nutrition of a healthy and sick person». Much attention is paid to illustrations of devices at the stages of laboratory studies of the studied hygienic factors, which is designed to facilitate the development of the discipline by students. All sections end with the final lesson, outlining the main questions on the theoretical and practical part of the topics covered, situational problems, approximate topics of reports, questions for independent work and tests. The manual has been approved and recommended for publication and use in the learning process by the decision of the Central Coordination Methodological Council of the DSMU.