Published Article / Construction projects all over the world involve many challenges, particularly for large public projects. The emerging complex nature of construction activities has brought with it characteristic features, such as, cost increases, delay in the delivery of project, to which rework (carrying out an activity more than one time) has a high contributing factor, stemming from imperfection. This study identified the sources of rework on construction projects in Nigeria from three perspectives: the client, contractor, and consultant. The study was concentrated on the South West part of Nigeria. The quantitative research method was adopted. Random sampling technique was employed in the selection of sample size. A total of one hundred and twenty (120) questionnaires were analysed using inferential statistics. The following are the findings of this study: the contributions of the client leading to rework are in the form of poor communication, inadequate construction planning and poor management practices. From the consultant, they are: lack of understanding and correct interpretation of customer requirements, constraints in carrying out activities and inexperience of personnel and on the part of the contractor they are: wrongly laying of forming course, poor quality concrete, and poor plastering. Based on the conclusions reached, the following recommendations were drawn. They are: the development of a standard information gathering format relative to clients 'by designers and clients' writing down their intentions before visiting designers; formal technical training should be given to foremen on permanent appointments with organisations, attention should be given for adequate supervision, and construction methods should be analysed before selection and their use.

After a century of sporadic advances in equipment, tools, materials, and methods, the US construction industry still faces a low rate of productivity growth. To improve the productivity of any site activity, it is important to rapidly record relevant data about utilized resources and processes, as well as about the output quantities produced by these activities. There is sufficient evidence to suggest that activity-level productivity measurement is the premise for making any productivity improvement decision. To date, certain aspects of productivity measurement, such as input/output quantities, are partially automated through advanced project control systems. However, measuring the process of construction activities for productivity improvement remains an elusive goal for most construction companies. This is mostly due to the massive manual effort embedded in these data collection methods. Digital cameras are inexpensive devices that are widely used in the construction industry as an effective site observation method. This opens the door for conducting scientific method studies on complex operations through examining recorded videos. However, in the absence of an efficient video interpretation method, tedious manual reviewing is currently still required to extract productivity information from the recorded videos. This research aims to develop a computational methodology to rapidly and intelligently interpret construction videos into productivity information. It determines what elements can represent the steps and information flows in construction video interpretation. It identifies, develops, and evaluates computer vision algorithms to enable reliable visual recognition and tracking of construction resources in typical construction environments. It develops methods to enable context aware video computing. A software prototype, the Construction Video Analyzer, was developed and implemented based on this conceptual methodology. The proposed methodology was validated through using the developed prototype system to analyze five construction video sequences that record various types of construction operations. The Construction Video Analyzer was able to interpret these videos into productivity information with an accuracy that was close to manual analysis, without the limitations of onsite human observation. The developed methodology provides site management with a tool that can rapidly collect productivity data with greatly reduced manual efforts. / text

Vid miljöövervakning av konstruktionsprojekt såsom byggnation av väg och järnväg är det vanligt att uppsatta riktvärden för grumlighet överskrids. I en genomgång av årsrapporter från infrastrukturprojektet BanaVäg i Väst visade det sig att riktvärden för grumlighet ofta sätts upp utan noggrann kartläggning av vattendragens naturliga grumlighetsnivåer. Detta arbetssätt beror förmodligen på den oklara lagstiftningen gällande riktvärden på grumlighet och på bristfälliga anvisningar för hur referensprovtagning av grumlighet bör utformas. För att komma åt problematiken med opålitliga riktvärden borde riktvärden därför anpassas till enskilda vattendrag. I detta examensarbete gjordes ett försök att ta fram en metod för att kunna sätta vattendragsanpassade riktvärden. En dynamisk modell utvecklades för att ta fram grumlighet utifrån jordbruksareal, andel lera i avrinningsområdet samt vattenflöde. Modellen gav bäst, men trots allt inte tillfredställande, resultat för vattendrag med avrinningsområden mindre än 100 km2. För vattendrag som hade ett större avrinningsområde blev modellresultaten sämre, förmodligen på grund av en komplex samverkan mellan olika drivvariabler, där vissa inte ens togs hänsyn till i modellen. För att komma vidare med vattendragsanpassade riktvärden i Sverige föreslås fortsättningsvis en omfattande nationell satsning framförallt för större värdefulla vattendrag. Denna satsning bör innefatta anpassning av mer avancerade modeller för grumlighet till svenska förhållanden. Sammanfattningsvis visar studien tydligt att det finns ett stort behov av att förbättra metoderna för att kontrollera grumlighet samt att ta fram riktvärden anpassade utifrån naturliga grumlighetsnivåer i de olika vattendragen. / It has been noticed that construction activities close to watercourses often result in turbidity values that exceed guideline values. A detailed analysis of annual reports from the Swedish infrastructure project “BanaVäg i Väst” has shown that recommended values of turbidity often are determined without consideration of natural variations in turbidity. The performance probably depends on the lack of appropriate legislation on acceptable turbidity values and on how turbidity should be monitored during construction activities. The objective of this thesis was therefore to develop a method to determine background values for turbidity as a basis for setting water system adapted reference values. In the thesis a model for turbidity was developed with agricultural area, clay content within the watershed and discharge as input variables. With the dynamic model variations in turbidity could best be explained in watercourses of watersheds less than 100 km2, but even for these watercourses the model performance remained poor. For watercourses draining larger watersheds the model performance became even poorer, most probably due to complex interactions of a variety of driving variables, of which some were not included as input variables. A recommendation is therefore a national initiative where more advanced models can be used, at least for large watercourses that are highly vulnerable, after adaption to Swedish conditions. This study clearly shows that there is an urgent need in Sweden to improve methods to monitor turbidity as well as to improve guideline values by adjusting them according to background turbidity levels.

The subject of the thesis "Rationalization of Construction price statistics" is to outline the issue of reporting of construction activities in the Czech Republic and try to be as simple as possible for statistical purposes, if possible. From a theoretical approach for construction work price indices and their stats go over to the practical part calculation of indices. Available data from the Czech Statistical Office on price indices of building work in recent years converted in terms of weights of permanent representatives from the perspective of individual statements. The goal is, to find a satisfying combination of representatives of both methodological procedures and exclude them from the forms for reporting. This should be saved in time statistical survey of individual respondents and abridged interpretation of outputs of the Czech Statistical Office.