The reasons for differences in calculations in investor’s and contractor’s estimations

The occurrence of differences between the employer’s estimate and the bid quotation is widespread and difficult to avoid. The differences between the investor’s and contractor’s calculations are often quite significant. This article analyses the differences between the value of the contract and the bid submitted for construction work carried out on a multi-storey buildings in 2013. An attempt was also made to analyse the reasons for such differences, providing possible ways to solve the problem

Integracja dokumentacji w procesie budowlanym z wykorzystaniem modelowania informacji o budynku

This paper presents a practical approach to the problem of data collection using the BIM model. The aim is to show how to use the BIM model to capture the data from the 3D design documentation, construction documents, construction schedule, and the use of BIM for the acquisition and storage of documents, including specifications, details of materials, information producers, workshop drawings, photographs, etc.Artykuł przedstawia praktyczne podejście do problemu gromadzenia danych z wykorzystaniem modelu BIM. Celem jest pokazanie sposobu wykorzystania modelu BIM do przechwytywania danych z 3D dokumentacji projektowej, dokumentów budowy, harmonogram budowy, a także wykorzystanie BIM do pozyskiwania i przechowywania dokumentów, w tym specyfikacji, szczegółów materiałowych, informacji producenckich, rysunków warsztatowych, zdjęć itp

Analysis of solutions for exterior walls in the bim model using the ahp method

This paper presents selected variants of thermal insulation for external walls of single family homes. The main aim of this article is to analyze the technological and economical solutions based on the BIM model. The technical and economic analysis concerns the calculation and evaluation of both the costs of constructing the walls and the energy demand of the model building designed by the authors. The last part of the paper compares and prioritises proposed solutions in regard to the accepted assessment criteria using the AHP method, which allows for selecting the best solution

The Concept of a Knowledge Base to Aid in Cost Estimating of Sports Facilities

Background. Reasoning based on cases is one of the heuristic techniques which is used in making right decisions in complex situations. Inference systems typically use previously acquired knowledge which is the basis for creating tools to represent and process information. So far, there has been a wide variety of solutions developed to make inference in conditions of incomplete knowledge, but this process appears in very few studies related to civil engineering.Research aims. This article will provide a concept of the model of knowledge base and a method of describing sports facilities. The cost estimation model will be based on the prices of the integrated works which, being based on the indicated system, will allow to create the module supporting cost and tender calculations. Methodology. The authors present the main assumptions of the concept of estimating the costs of sports facilities with the use of the system of inference on the basis of cases (CBR – Case-Based Reasoning).Key findings. The indicated method is designed to improve the accuracy of estimating the costs of planned sports investments and improve the decision-making process at the planning stage

Analysis of a passive design sports hall: construction and use

This article presents an analysis of how the construction and insulation materials used for the walls of a sports hall built according to passive design affect the overall construction costs. The authors also attempt to answer whether the objective of achieving the lowest possible energy consumption in a building is actually economically sound. Cost analyses will be carried out to this end, the optimum insulation thickness will be determined, and the time necessary to balance the investment expenditure will be calculated for an energy-efficient construction project

Possibilities of Reducing Energy Costs in the Life Cycle of Office Buildings

Buildings absorb energy at every stage of the life cycle. The paper analyses the phases of the life cycle of an office building indicating the possibilities of reducing energy consumption. In particular, attention was paid to the most energy-intensive phase, that is the use phase. Both simple actions and more advanced solutions allowing to reduce the energy demand of a building during the use phase are characterized. For an exemplary office building, life cycle costs were calculated taking into account selected solutions improving energy efficiency

Forecasting of sports fields construction costs aided by ensembles of neural networks

The paper presents an original approach to construction cost analysis and development of predictive models based on ensembles of artificial neural networks. The research was focused on the application of two alternative approaches of ensemble averaging that allow for combining a number of multilayer perceptron neural networks and developing effective models for cost predictions. The models have been developed for the purpose of forecasting construction costs of sports fields as a specific type of construction objects. The research included simulation and selection of numerous neural networks that became the members of the ensembles. The ensembles included either the networks of different types in terms of their structure and activation functions or the networks of the same type. The research also included practical implementation of the developed models for cost analysis based on a sports field BIM model. This case study examined and confirmed all of the four models’ predictive capabilities and superiority over models based on single networks for the particular problem. Verification including testing and the case study enabled selection of the best ensemble-based model that combined ten networks of different types. The proposed approach is prospective for fast cost analyses and conceptual estimates in construction projects

A procedure of repairing housing defects in development investments

The article presents the results of the analysis of defects revealed by the supervision inspector during the acceptance of works in one of the Krakow multi-apartment buildings. During the tests, it was found that the most frequently occurring defects include: cracks in walls and ceilings, scratched glass, lack of straight angles between the walls or scratched window sills. There is an average of 11.32 defects per apartment and 0.23 defects per square meter of apartments. It was revealed that very significant, significant and insignificant defects had a similar quantitative share. A procedure for the reception of apartments was proposed, which will be the basis for the development of a mathematical model supporting decision making at the time of acceptance

SZACOWANIE WSTĘPNYCH KOSZTÓW BUDOWY BOISK SPORTOWYCH Z WYKORZYSTANIEM WNIOSKOWANIA Z PRZYPADKÓW

W artykule zostanie pokazane zastosowanie metody CBR (Case Based Reasoning) na wczesnym etapie budowlanego procesu inwestycyjnego w celu szacowania kosztów boisk sportowych. Analiza ma na celu zbadanie możliwości wspomagania kosztorysowania robót budowlanych z wykorzystaniem wnioskowania z przypadków. Zaprezentowana zostanie baza danych zawierająca 84 przypadki boisk sportowych dla których przeprowadzono postępowania przetargowe. Baza danych zawiera także ceny wybranych ofert w toku postępowania. Następnie pokazano proces wnioskowania z przypadków w celu wyboru najbardziej zbliżonych przypadków do analizowanego problemu. Obliczone zostały lokalne podobieństwa przypadków nowych i starych zawartych w bazie danych, a następnie podobieństwo globalne. Wybrane zostały przypadki, dla których podobieństwo globalne było większe niż 95%. Wybrane przypadki zostały następnie adaptowane ze względu na różnice w czasie kalkulowanych ofert starych przypadków, a czasem oszacowania dla nowego przypadku oraz różnic w lokalizacji inwestycji. W tym celu dokonano korekty o dwa współczynniki korekcyjne: współczynnik waloryzacyjny i współczynnik regionalny. Obliczenia przeprowadzono dla czterech modeli różniących się przyjętymi wagami zmiennych objaśniających przypadki oraz ilością zmiennych dla których obliczane były podobieństwa lokalne. Na koniec wyliczono średni absolutny szacowany błąd MAEE dla analizowanych modeli i dokonano analizy błędów w odniesieniu do publikowanych wskaźników polskich oraz zagranicznych w celu oceny błędu dla analizowanych modeli