| Abstract [eng] |
The review part of the master's thesis analyzes the scientific literature of Lithuania and foreign countries related to the wooden structures of pitched roofs. A brief overview of the historical design solutions for pitched roofs. Types of wooden structures of sloping roofs and their components are analyzed. The most common errors that determine the durability of wooden structures of a sloping roof are considered. Recent research in the field of roof construction solutions, the application of which can reduce the negative impact on environmental pollution, is reviewed. The methodological part of the work presents the classification of multi-criteria evaluation methods, evaluates various multi-criteria methods with each other. Their simplicity, computation time, reliability, etc. are compared. The scientific literature describing the successful application of the MOORA method in various fields is reviewed. The algorithm for the implementation of the MOORA method is presented in the work. In the research part of the work four types of wooden roof trusses are investigated. The same external dimensions of all roof trusses and different layouts of internal elements are selected. Wooden roof trusses are designed to withstand the technical use loads of snow, wind, roofing, ceilings and attics. The total length of the investigated trusses is 13.7 m, the trusses cover a span of 12 m. In the work, after interviewing construction experts, the evaluation alternatives of the wooden truss of the sloping roof are presented and the most rational variant is selected by the MOORA method. The order of alternative priorities is determined according to the truss weight, deflection, price of materials, number of joints, volume of wood in the insulation layer and indicators of the possibility to use the attic. Autodesk AutoCad, Robot Structural Analysis Professional 2022, Microsoft Excel programs are used to draw and calculate trusses in the research part. The object of the research is the wooden constructions of pitched roofs and their installation technologies. The aim of the work is to perform a multi-criteria evaluation of the efficiency of a wooden roof truss. Work task: 1. To analyze the scientific literature of Lithuania and foreign countries related to the wooden constructions of sloping roofs. 2. To present the classification of multi-criteria evaluation methods and the evaluation algorithm of the MOORA method. 3. To present the evaluation alternatives of the wooden truss of the pitched roof and to select the most rational variant by the MOORA method. To determine the order of alternative priorities according to the indicators of truss weight, deflection, price of materials, number of joints, volume of wood in the insulation layer and the possibility of using the attic. Research methods: analysis of scientific and technical literature, survey of experts, MOORA method. The main results and conclusions of the research. Empirical research using MOORA method investigated four different types of pitched roof trusses according to the weight of the timber structure, the price of materials, the number of joints, the volume of wood in the insulation layer, the maximum deflection and the technical use of the attic. A truss with four springs (type I) was found to be the most effective in covering a 13.7 m wide roof. The master 's final project consists of: abstracts in Lithuanian and English, introduction, 3 chapters, conclusions, references, list of information sources. The work consists of 66 pages with 18 tables, 34 pictures and 4 appendices. |
