Czech Journal of Civil Engineering

Development of prices in the civil engineering – analysis of the situation

2023-06-30T22:22:18+00:00

The market in the construction industry is currently so unstable that no one can even estimate its development. The increase in the prices of building materials in current values was an absolutely unexpected event. In addition to materials, the prices of labor, fuel, overheads and other components of the formula also increased. The price development index has become an unpredictable event that fundamentally affects the construction market. Both contractors and investors have become more cautious and cautious. contracts begin with indexation clauses. Competent organizations reacted with distance and issued methodological guidelines for the public sector. The published methodologies in the field of honey reflect the market, but they are not covered by the overall increase or inflation. Methods of determining price changes were the subject of earlier authors who dealt with this issue. One of them is the use of directional orientation tools published in available databases. The article approximates the predictability of prices, methods of determining the growth of construction prices and evaluates the currently valid methodology for the public sector.

Options for creating a basic passport

2023-06-30T22:34:27+00:00

Currently, the term passport is mainly used in construction practice for the purpose of a legal act connected with construction. For example, it is used during approval, where its detail and need are defined by legislation. In addition to this defined passport, detailed documentation of the state of the building at a certain date, i.e. at a decisive date, is also used. By default, the passport is made by the designer. However, there are other purposes for passports that are drawn up by experts. We can call this a basic passport. It is used by experts in various tasks according to the questions. The processing of the passport includes an inspection, the processing itself and the creation of outputs. Every action requires a certain effort, detail and commitment. According to the question for the expert and the direction of the expert act, the expert must choose the correct procedure. The article brings closer the possibilities and available technologies for such documentation of a certain state of the building to a specific date. It approaches and illustrates the method of photography, the use of software support and spatial laser scanning. The article describes individual methods and approximates the advantages and disadvantages of individual methods and procedures. In the end, he verbally evaluates individual methods.

Data-oriented approach for moisture reduction in heritage buildings

2023-06-30T22:35:17+00:00

Today, several measurement methods aimed at identifying the moisture level of building structures are used in practice. The measured data can be connected to the information model of the building, resulting in an organized database, which will enable not only a better and more complex evaluation, but will enable the automation of the evaluation with the use of artificial intelligence. The problem is mainly the absence of building information models, which are not available especially for historical objects. In this article, we focus on the creation of a methodology for the systematic collection of data on humidity conditions in the constructions of monumental buildings, which will be the basis for the proposal of appropriate measures for adjustment. The first step is the digitization of the building through photogrammetry or terrestrial laser scanning. The second step is the creation of a building information model. The last step is to connect the information from the measurement with the building information model. Enriching BIM with a data set of moisture records from various buildings can significantly contribute to a better understanding of the degree of wetting, identification of causes and also help to choose appropriate measures based on proposed measures in the past.

Lever arm calculating algorithm for efficient and precise vector determinations

2023-06-26T22:26:10+00:00

In the orthophoto processing one of the key steps is the aerial triangulation during which the exterior orientation coefficients of the photographs are determined by adjustment. In order to be able to do this with sufficient accuracy, in addition to knowing the internal orientation elements of the cameras, we need the eccentricity vectors of the GNSS antennas, IMU and sensors determined in relation to each other, i.e. the lever arms. Characteristic points of the airplane and the installed instruments are measured using 3D polar method, while vectors are traditionally determined using a geometric technique. In this paper we will present an algorithm which uses an analytical geometric approach for much quicker and more precise results.

Forecasting the development of prices for construction works and materials in the construction industry in Slovakia and abroad

2023-06-30T22:31:27+00:00

This article deals with the increase in the prices of construction works and materials in the period from the beginning of 2016 to the end of 2022, when the market was and still is very unstable. The value of the price development index of construction works and materials in the most unstable period increased by 35.2 percentage points, in 15 months. Given such price developments in the construction industry, it was and still is almost impossible for contractors to adhere to contractually agreed prices in both the public and private sectors. For construction contracts in Slovakia and abroad, are mostly used types of contract prices. A contract based on unit prices, when the contractor undertakes to fulfill all conditions, provided that the actual incurred own costs and a reasonable profit are paid. A contract with a fixed price (flat price) obliges the supplier to perform work and deliveries, regardless of his own costs incurred in connection with the delivery specified in the contract. Is it even possible and expedient under these uncontrollable conditions to forecast the development of prices in the construction industry? What forecasting methods could be effective for this purpose?

Architecture and real estate market – own residence and current condition

2023-05-25T13:22:40+00:00

Architecture is part of the everyday life of every person in the world. We can perceive it from large and spatially demanding units to a small detail, which we perceive only through closer interaction. But housing is one of those forms that almost every one of us will solve and also means something to everyone. For many people, the question of their own housing is even a fundamental life value and a goal they are trying to reach. Owning real estate = succeeding in life. Is it like that or not? Is our own home even attainable for us at the moment? Maybe today we are stagnant and clinging to goals that currently do not make as much sense as before. Do the properties being sold really have the value they are being offered for on the market? Current trends in the area of new residential construction and the real estate market say rather the opposite. But is this attitude sustainable or are we soon approaching a threshold that means fatal consequences? And what can we - as ordinary people - do to get closer to our dreams of owning and, above all, satisfactory housing?

Air flow in the crawl space

2023-06-16T08:43:56+00:00

The strip foundation with a concrete slab on-ground is common type of foundation in Central Europe. The crawl space is rather exceptional in Central Europe. The paper deals with the air flow and temperature and moisture condition in a naturally ventilated crawl space in the Czech Republic. The monitoring of crawl space took place from April 2022 to February 2023. The air flow, air temperature and relative humidity was continuously monitored in the crawl space. On selected summer days, the space rate changing air was also monitored. Base on the average outdoor air flow, the summer day was selected. The space rate changing air was high during June in the crawl space. On the selected days, the avarage values ranged from 5 ach to 12 ach. In the Czech Republic, there is not Czech Standart that deals with design air flow in the crawl space In the United States, requirements are describes in International Residential Code (IRC – International Code Council). When applying this Code, it was detected the area of ventilation holes in the monitoring crawl space was twice as large as recommended by the International Residential Code.

Experimental study of properties of concrete with dosage of recycled steel fibers

2023-06-30T22:27:39+00:00

Currently, is observing a huge increase in waste tires in the world. Over 1 billion waste tires increase yearly, bringing environmental and health issues. Material recovery of particular waste allows for obtaining recycled steel fibers (RSF). RSFs incorporated in concrete significantly improve recycled steel fiber reinforced concrete's tensile strength and energy absorption (RSFRC). The goal of the experimental research presented in this paper is to investigate the compressive strength of RSFRC, tensile splitting strength and to determine particular fracture mechanical parameters of RSFRC with different doses of RSF. RSFRC compressive strength tests were carried out on three samples for each batch of RSF according to STN EN 12 390-3. Determination of tensile splitting was executed according standard STN EN 12390-6 in case three specimens, cilinders in shape. Selected fracture mechanical properties were determined on three RSFRC beams with a notch for each batch of RSF according to JCI-S-001-2003 and JCI-S-002-2003. Experimental research has shown that with a dose RSF higher than 1.9% by volume an increase in RSFRC compressive strength was observed. Further was invented, that with increase dosage of RSF increase tensile splitting strength of concrete. The bending test result is an increasing trend of fracture energy with an increasing dose of RSF. From this experimental research, it emerged that it is necessary to choose a dose of RSF of at least 1.9% by volume.

EDITORIAL Vol. 9, Issue 1 (2023)

2023-07-20T12:30:58+00:00

Title page + Editorial Board + Scope & Imprint + Contents