ANALYSIS OF PROPERTIES OF THE FRP REBAR TO CONCRETE STRUCTURES

The application of the FRP (Fiber Reinforced Polymer) rebar is presented in this paper. The various kinds of fibers, depending on the types of the FRP rebar and types of matrix of FRP are listed. The main tasks of matrix and fibers are specified. The two methods of FRP bars production are explained. The selected physical and mechanical properties of the various types of the FRP rebar are shown and compared. The long-term properties of the FRP rebar, as relaxation and creeping processes, are also introduced. The FRP properties were compared to conventional steel reinforcement properties. Moreover, the typical disadvantages of traditional reinforced concrete, as the susceptibility to corrosion were presented. It is shown that the FRP reinforcement is quite opposite, since it has almost total resistance to corrosion. The corrosion factors, to which the FRP is resistant, are presented and explained

THE STRUCTURAL SOLUTIONS OF THE TIMBER ROOFS: JOINTS AND JOINING PLATES

In the article the authors present the practical design solutions regarding to structural timber roofs, especially the carpentry joints. The selected factors and parameters which should be respected during the correct static scheme of the roof structure selection are presented. The main differences between the two widely used and visually similar static schemes of roof systems are listed: the rafter – collar tie and the rafter – doubled collar tie roofing systems. A concise comparison of the structural work of these systems is presented. Primarily, in the paper the selected joints and joining plates were discussed in detail. The most popular traditional solutions of used carpentry joints and the new, alternative ones are described. The advantages and disadvantages of discussed solutions are pointed, as well as the advices on their practical use in the construction industry. As a conclusion, based on the conducted research it can be stated that using the innovative solutions of joints and joining plates avoids the most common assembly errors and are a good solution for joining the structural elements of the timber roofs

Use of the Toyota management principles for evaluation of the company’s mission

In the paper there were described the elements of the Toyota roof. Electroacoustic products were characterized. Immaterial resources of the company were analyzed. To do so, the BOST survey, whose questionnaires were filled in by employees of the chosen enterprise, was used. Particular attention was paid to the following factors: quality, costs, lead time, work safety and personnel moral

Jakość obsługi klienta w bezprzewodowej telefonii komorkowej

Момент, когда начали оценивать и замечать сферу услуг, наступил относительно недавно. Этот сектор начали замечать и приписывать ему значительную роль в разного рода фирмах. Эта работа, поднимая вопрос качества обслуживания клиента в радиотелефонной сети, не дает исчерпывающего ответа. Факторами, которые имеют решающее влияние на качество обслуживания, считают следующие: пред- и послепродажное обслуживание в дилерских группах; вид используемого телефонного аппарата; вид и сила сигнала, передаваемого наземными приемно-передающими станциями. Все из перечисленных факторов воздействуют в одинаковой мере на качество обслуживания, но отсутствие одного из вышеперечисленных факторов приводит к невозможности реализации услуги. Стратегия развития фирмы старается объединить людей и приблизить их к постижению сегодняшнего мира, мира информации и цифровой техники, а также пытается показать дружественный облик последней. Служить этому должны различные заботы о благе клиента и желание служить ему, а также предложение ему своих услуг на как можно высшем, мировом уровне. Приятное обслуживание, желание быть полезным 24 часа в сутки, квалифицированные рабочие кадры, постоянно повышающие свою квалификацию, являются столпом развития фирмы, ориентированной на потребности клиентов

ANALIZA DWUWARSTWOWEJ POWŁOKI ŁUKOWEJ NA PRZYKŁADZIE PRZYKRYCIA HALI SPORTOWEJ

W artykule przedstawiono analizę dwuwarstwowej powłoki łukowej stanowiącej przykrycie hali sportowej. Przykrycie walcowe wykonano z blachy grubości 1 mm kształtowanej na zimno. Profil blachy składa się z dwóch środników z górnym wygięciem poprzecznym połączonych u dołu z półką dolną. Przestrzeń dystansową między powłokami wypełniono dwiema warstwami wełny mineralnej. Dach opiera się przegubowo na żelbetowej konstrukcji wsporczej. Podparcie ciągłe zrealizowano za pomocą liniowego kątownika oporowego oraz blach nachylonych pod kątem 60 stopni. Analizę konstrukcji, wytrzymałościową i wyboczeniową, z uwzględnieniem nieliniowego zachowania materiału i możliwości utraty stateczności (GMNA) wykonano w programie ANSYS, w oparciu o model belkowy oraz powłokowy. Powłoki połączono ze sobą elementem podatnym o charakterystyce materiału przenoszącego tylko siły ściskające. Włączenie do współpracy powłoki dolnej z górną, odbywa się gdy materiał podatny (wełna mineralna), zostanie pod działaniem obciążenia ściśnięty o wartość przekraczającą 60 mm, zmienia się wówczas charakterystyka materiału, który z podatnego staje się bardzo sztywny. Obliczono długość wyboczeniową łuku kołowego przegubowo podpartego na obu końcach oraz określono wartość imprefekcji geometrycznych łuku. Konstrukcje obciążono zgodnie z wymaganiami aktualnych norm PN-EN i stworzono kombinacje obciążeń. Dla najbardziej niekorzystnego przypadku obciążeń przedstawiono ścieżki równowagi, zarówno dla modelu powłokowego jak i belkowego. Dla modelu belkowego pokazano ponadto wykres naprężeń Hubera-Misesa oraz wartości ugięć

The computational analysis of the crack width of beams reinforced with CFRP and steel bars

The aim of the paper is to explain the particular problems related to the use of FRP reinforcement in bending beams. The paper compares the aspect of Serviceability Limit State (SLS) of simply supported concrete beams reinforced with Carbon Fiber Reinforced Polymer (CFRP) bars and three various types of steel bars (the steel grades are 35G2Y, 20G2VY-b and B500SP). The computational analysis of change in crack width under the influence of various level of service live load was investigated. The calculations of beam reinforced with FRP bars was based on Italian design guideline (CNR-DT 203/2006) and the conventional reinforced concrete beams (RC) were analysed in accordance with the European standard Eurocode 2 (EN 1992-1-1:2004)

Weight minimization of spatial trusses with genetic algorithm

A genetic algorithm is proposed to solve the weight minimization problem of spatial truss structures considering size and shape design variables. A very recently developed metaheuristic method called JAYA algorithm (JA) is implemented in this study for optimization of truss structures. The main feature of JA is that it does not require setting algorithm specific parameters. The algorithm has a very simple formulation where the basic idea is to approach the best solution and escape from the worst solution. Analyses of structures are performed by a finite element code in MATLAB. The effectiveness of JA algorithm is demonstrated through benchmark spatial truss 39-bar, and compare with results in references

Influence of the percentage of reinforcement damage on the bearing-capacity of RC beams

This article presents the test results of reinforced concrete beams with different percentages of reinforcement damage. One of the main causes of structural damage is corrosion. The main cause of corrosion is an aggressive environment, which can endanger the environmental ecology. During the study, the effect of damage to reinforced concrete beams was investigated. The beams were produced full-sized, 100x200x2100 mm. According to the research program, 6 beams were tested, including undamaged control samples with a single reinforcement bar of ∅20 mm - BC-1 and BC-2; samples with a reinforcement bar of ∅20 mm with about 10% damage - BD-3 and BD-4; samples with a reinforcement bar of ∅20 mm with about 20% damage - BD-5 and BD-6. The reinforcement bar was damaged before concreting the samples. As a result, it was determined that a reduction in the bearing-capacity of the reinforced concrete beams depended on the percentage of damage to the reinforcement bar

Analysis of FRP bars used as reinforcement in concrete structures

In the design and construction of building and engineering structures, it is of utmost importance to provide their reliability and safety. The use of FRP (Fiber Reinforced Polymers) bars as reinforcement of structural concrete elements could help reducing the typical defects of reinforced concrete and increase its strength parameters. In the paper the selected FRP bar characteristic properties are presented and advantages derived therefrom are specified. Furthermore, the most commonly used in construction types of FRP bars, depending on the raw material used during the production process are listed. In addition, the possibility of recycling of elements reinforced with FRP bars is presented and compared with traditional reinforced concrete (reinforced with steel bars). The production method of FRP bars (pultrusion) is shown. Moreover, the advantages and disadvantages of using this method are discussed