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Hydrotechnical constructions are mostly objects functioning in extreme conditions and requiring a custom-made construction project. In the case of using prefabricated elements, it is required to develop production, transport, assembly, conservation and repair technology. Concerning the problem of concrete cracks, modern repair systems allow positive effects to be achieved in many cases of concrete elements repair. In this work an attempt has been made to assess the properties of concrete, situated in the Baltic Sea environment, in which traditional rebar was partly replaced by dispersed fibre-phase. Fibre-reinforced concrete belongs to the group of composite materials. The presence of fibres helps to increase the tensile strength, flexural strength and resilience and also prevents the appearance of cracks. In the given paper we will also discuss basic parameters of steel and polymer fibres and the influence of both types of fibres on the maturing and hardened concrete. In this work special attention has been paid to the advantages of polypropylene and polymer fibres with regard to commonly-known steel fibres. The use of synthetic fibres will be advantageous in constructions where the reduction of shrinkage cracks and high resilience are essential. On top of that, the use of synthetic fibres is highly recommended when constructing objects that will be exposed to the impact of an aggressive environment. Undoubtedly, polymer fibres are resistant to the majority of corrosive environments. Fibre-reinforced concretes are a frequently implemented construction solution. The possibility of concrete modification allows the emergence of new construction materials with improved physical-mechanical properties, under the condition of being applied relevantly.

Today barrier types are frequently selected for their price with little regard for the total costs the structure will incur over its lifetime. One of the basic tools designed to manage road infrastructure is the life cycle cost method (LCC, Life cycle cost). It sums up the costs to plan, design, build, operate (use and maintain) and decommission a road structure. Having developed dynamically at the turn of the century the method is now widely applied in a number of industries including traffic engineering. Today, depending on data availability and calculation complexity, two groups of life cycle assessments are distinguished: analytical and parametric. Unfortunately, each comes with some limitations and the search for a new universal life cycle cost calculation method continues. The authors propose their own general concept of a method for estimating the life cycle costs of road safety barriers. The article presents a multi-stage process to build the method which is based on international experience and real test site data.

The aim of the regulation in EU countries concerning public procurement is to ensure efficient spending of funds by evaluating and choosing the most advantageous offer. The aim of the conducted research is to determine the extent the Polish contracting entities benefit from the possibility of broad selection of various criteria for tender evaluation. On the basis of the analysis of 500 notices on work procedures conducted in the third quarter of 2016 - the third quarter of 2017 in open and restricted tenders in Poland and 500 tenders in open and restricted proceedings in five selected EU countries, the authors compared and classified of applied the practical criteria to evaluate and select the best offer. In order to collect the information presented in the article, the authors applied the documentary method using domestic and foreign literature regarding the subject and official publications.

The authors demonstrate how expert knowledge about the construction and operation phases combined with monitoring data can be utilized for the diagnosis and management of risks typical to large civil engineering projects. The methodology chosen for estimating the probabilities of risk elements is known as Bayesian Belief Networks (BBN). Using a BBN model one can keep on updating the risk event probabilities as the new evidence (monitoring information) becomes available. Furthermore, the updated probabilities estimated using the available data for the construction phase serve as background information for the subsequent phase. The integrated two-object model of construction-operation may be then used to optimize the decision making, thus minimizing the risks. To better show how the proposed approach works the authors use the example of the road tunnel constructed and operated under the Dead Vistula River in Gdansk.

The costs borne by road infrastructure authorities for managing and maintaining road devices such as safety barriers may be very high. This has prompted the need for identifying and analysing in detail all factors that influence the costs of safety barriers throughout their service life. To meet that need, the authors used international experience and field data collected under the LifeRoSE project to define the cost structure and, as a next step, to analyse factors that are relevant to the costs actually incurred.

An important goal, implemented by EU countries under the Europe 2020 strategy, is sustainable development, which includes supporting economy that effectively uses natural and environmentally friendly resources. Solutions in this area are also promoted in tender proceedings in the area of public procurement. The LCA (Life Cycle Assessment) and LCC (Life Cycle Cost) analysis are indicated as the basis for decision-making by awarding entities. In the article, the authors present on the selected example the benefits of using LCA and LCC. Based on the documents analysis for 350 selected public procurement procedures conducted in Poland in 2017, the authors examine types, average weights and frequency of application of non-price criteria for the selection of the best offer in practice. Based on the results of the research, are formulated conclusions.

The article analyses environmental and ecological criteria of selecting the most beneficial offer in the aspect of LCC. Construction works contracts and the potential method of defining the above criteria, among others, is pondered on (for example by the recommendation of a material, which is supposed to be used, a ban on substances that are harmful for human health as well for the environment). In the relation to the above, it is necessary to define technical parameters that have an impact on the environment, for example the level of pollution and noise emission, electricity and water consumption, or stating the minimal involvement of a processed ingredient. In addition the article presents also an account of the life cycle cost of a building from the point of view of environmental criteria constituting an element of selecting the most beneficial offer in the area of competitive tendering.

In the article, the authors discuss the preliminary information necessary to determine the scope and direction of further research conducted within the project called “The influence of time and operating conditions on the durability and functionality of road safety elements”. The main objective of the project is to develop the concept of a method for optimizing the life cycle costs of road safety devices. The authors draw attention to the close connection between the decisions taken at the design stage and expenses incurred in the course of maintenance and the use of road safety devices, present the specificity of road infrastructure in terms of life cycle costs, discuss the components of the costs and give examples of the LCC analysis applied to the concrete barrier.

Global economic growth causes an increase in natural resources exploitation, particularly in construction branch. The growing use of electricity contributes to climate change. Therefore, it is necessary to search the solutions, which will allow for reducing natural resources exploitation. One of the many opportunities to do that is the application of the recycled materials. The authors of the given article have analyzed three variants of construction solutions. One of them was the production of the walls of a building from reinforced concrete prefabricates with styrofoam insulation layer. The second variant for analysis were prefabricated walls from lightweight concrete, made of sintered clay aggregate with a foam core. The third proposed variant was a system of multi-layered walls, which was made of lightweight concrete with granulated expanded glass aggregate (GEGA). The main objective of the research was to assess the use of lightweight GEGA prefabricates, focusing on economic and technological aspects of the solution. The authors have analyzed the entire construction costs; ceilings and stairs were assumed as reinforced concrete elements. In calculations, the weight of the elements was taken into account, as well as transportation and mounting costs. On the basis of this cost analysis, it was concluded that the use of prefabricated element, made of lightweight concrete with GEGA, could be a replacement for the solutions, widely applied until these days. The analysis has also shown that the use of prefabricates with GEGA is sensible from the economic viewpoint, as it allows for saving construction time. Moreover, the solutions, proposed here, allow for saving natural resources and assuming a more environmentally friendly and caring attitude. [ABSTRACT FROM AUTHOR]