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Vliv chemické a tepelné modifikace na mechanické vlastnosti bukového dřeva
Vodák, Michal
The presented diploma thesis is focused on the analysis of the influence of selected beech wood (Fagus sylvatica L.) modifications and its behavior under mechanical stress. Beech samples were modified with acetic anhydride, with melamine-formaldehyde resin and thermally modified using temperatures 180, 200 and 220 ° C. The shear moduli and shear strengh parallel and perpendicular to the grain, compression moduli a compression strenght parallel and perpendicular to the grain and 3point static bending moduli and strenght perpendicular to the grain were determined. The mechanical behavior of the modified wood was studied under various MC conditions, i.e., oven dried at 103 ± 2 °C to 0 % moistruce content, conditioned at 65 % relative humidity and 20 °C and conditioned at 90 % relative humidity and 20 °C. The digital image correlation (DIC) method was employed as a virtual extensometer to observe stress-strain diagrams. The results show a statistically significant effect of wood modification on mechanical behavior in the context of equilibrium moisture content. More significant percentage changes were observed for yield strength values compared to the modulus of elasticity. Acetylation of wood lowered the effect of moisture to a statistically insignificant value in the case of modulus of elasticity measured by 3point static bending. Wood acetylation also led to increase of the compressive strength perpendicular to the grain by about 100 %. All types of wood modifications have shown the potential for commercial use, even for structural applications. However, a specific method must be selected based on the requirments of designed construction. It is not possible to determine one modification method that would perform best across all applications.
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Shear Resistance of Prestressed Beams According to the Different Design Approaches
Baran, Jaroslav ; Borzovič, Viktor
The contribution deals with the shear resistance of prestressed beams and aims to compare experimental results with different design approaches. The experiment included two experimental tests on a sample prestressed beam. The course of the experiment is briefly described in the discussion. The prestressed beam, with an I cross-section, had bonded tendons and a total length of 7.0 m. A detailed description of the beam reinforcement, material characteristic and test setup are included. The reliability of individual design approaches is compared based on the analysis developed in this contribution.
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Design of reinforced concrete structure with respect to fire resistance requirements
Pivodová, Alena ; Klodner, Jan (referee) ; Perla, Jan (advisor)
The diploma thesis deals with an analysis of internal forces of B4 reinforced construction of an office building. Analysis takes into account interaction with subsoil and when designing structural parts of the building, different requirements for fire resistance of a structure are taken into account. A Dlubal RFEM 5.17 program was used for finite element analysis, and model functionality verification was performer by using a summation of moments method. The thesis deals with the design and assessment of a point-supported slab, column, inner and external walls.
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Overpass bridge across the highway
Černý, Pavel ; Šopík,, Leonard (referee) ; Nečas, Radim (advisor)
The topic of this thesis is detailed design of the supporting structure of a bridge. Three variants are designed. The structure is designed as a single beam bridge of 6 spans. The calculation of load efects make in software MidasCivil 2019 and Scia Engineer 18.1. The subject of the expertise of the structure is service limit state and ultimate limit state. For evaluation of cross sections is used MS Excel. Both design and relevant drawing documentation of the bridge deck and substructure. The design and assessment are according to the europien standards.
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Sewage pumping station
Kustyánová, Orsolya ; Šulák, Pavel (referee) ; Strnad, Jiří (advisor)
This thesis deals with the design and assessment of all supporting parts of a reinforced concrete sewage pumping station in the village Vrbice u Velkých Pavlovic. The main parts of the thesis are the technical report, static analysis, drawing documentations and visualisations. Calculation of internal forces was performed by the software Scia Engineer and verified by manual calculation. The drawing documentation consists of shape and reinforcement drawings of supporting parts.
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Design of the speed-way bridge structure
Nádvorník, Ondřej ; Rybák, Vít (referee) ; Klusáček, Ladislav (advisor)
This Master's thesis deals with the detailed design of the supporting structure of the bridge with two sections, with the rise in the direction of the intermediate support, and cross-cut single-beam construction. The supporting structure is designed from the prestressed concrete, prestressing losses are accurately quantified. It also deals with the assessment of pillar base threshold and pilot groups. The assessment was carried out according to the limit states.
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The use of advanced composite materials for the design of concrete structures
Macháček, Jan ; Matušíková, Anna (referee) ; Girgle, František (advisor)
The diploma thesis deals with the design of concrete structures reinforced by FRP according to ACI, fib, CSA and EC2 regulations, which are stressed by a shear force. The diferences between steel rebar and FRP reinforcement were described, in particular its mechanical degradation over time and a different stress-strain diagram. Furthermore, shear capacity calculations were performed according to the regulations and compared with the real tests. Then the parametric analysis of shear strength was performed. In the practical part, the design of concrete floor slab structure supported by the pillars and walls was performed. The upper reinforcement of this slab was designed with FRP and the lower with steel rebar. Double-headed studs were used as a punching shear reinforcement.
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On the cutting geometry and kinematics of the arthroscopic forceps part
Pospíchal, Oldřich ; Polzer, Aleš (referee) ; Píška, Miroslav (advisor)
This Thesis presents a design innovation in arthroscopic forceps. Based on surveying the subject-matter literature on arthroscopic surgery of the knee, design changes are proposed to alter the cutting geometry of the functional end of the instrument to improve its utility. The proposed changes are imple-mented in a prototype, which is then compared with the current design. The comparison is made by testing the functioning of the instrument and the force required to shear the test material.
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Concrete flat slab supported by columns
Lehoťák, Roman ; Švaříčková, Ivana (referee) ; Perla, Jan (advisor)
The bachelor thesis deals with the analysis of internal forces and the design of the shape and reinforcement of the reinforced concrete monolithic slab, the ceiling above the 6th floor of the University Hospital in Bohunice. The calculation of internal forces was performed by the substitute frame method and the finite element method in the Nemetschek Scia Engineer 18.0 program. The work deals with the design and assessment of the board and adjacent stairs.
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