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Civil, Architectural, and Environmental Engineering / Improvements on construction productivity benefits projects. These benefits are diverse and varied. Costs can be reduced, schedule performance can be improved, skilled labor shortage can be mitigated, and much more. These last few years, construction sites have undeniably made significant progress through advances in heavy equipment, tools, and materials. But there are still some areas that have strong potential to improve construction productivity such as craft information systems, materials management, and construction methods, which abound of opportunities that just need to be pursued. Innovations represent some of these opportunities, however if established process and practices for managing construction productivity are not effectively utilized and implemented, they are likely to have a little impact on construction productivity. This thesis summarizes a research study which aimed to identify productivity practices that have the most significant positive impact on craft productivity and to document and incorporate them into an implementation resource. Surveys involving over a hundred experts and extensive literature review were used to gather accurate data. Construction industry and civil engineering academic experts were also consulted to accomplish this goal. / text

This thesis sets out research carried out to investigate the usefulness of a descriptive database of construction methods for safety assessment. In addition, it investigates the possibility of utilising construction images as sources of safety related information. / The construction industry has been recognized as a hazardous work environment with a high accident rate for years, hence, site safety is a problem. Nowadays, the use of construction images in the form of photographs is commonplace and they are used as sources of information. The literature review reveals that they have never been used as sources of information concerning construction safety practice. / A preliminary investigation is conducted to study the possibility of utilizing construction images as sources of safety related information. The findings revealed that it is possible to use construction images as sources of information for construction safety assessment however, there were problems related to image interpretation and dissimilar safety judgment. It was assumed that those problems were arising from lack of safety knowledge and experiences, also no safety assessment method existed that could be used when using images as sources of information. / To overcome problem related to the existence of safety assessment method, the research developed a method to assess safety by using information observed from images. As a similar safety judgment would be obtained from a same guideline therefore, a safety guideline was established, including safety checklist and safety scores. To give meaning of sets of safety score, two methods of conditional probability approach from Artificial Intelligence that quantitatively deal with uncertainty, the Bayes’ Theorem and the Fuzzy Logic Theory, were employed. The Bayes’ Theorem formula was adopted for calculating a likelihood of a hypothesis being true based on evidence or P(H/E). The hypothesis used in this research that a safe construction practice being used. The evidence used to test this hypothesis is information collected from construction images. This method allows construction practices shown in the images to be defined as having a high level of safety or low level of safety. / The construction practices with low level of safety do not need to analysed further. Fuzzy logic theory can then be used for further classifying those images identified as having a high level of safety into one of three classifications: “most likely safe”, “fairly safe” or “most likely unsafe”. / To overcome problem related to lack of safety knowledge and safety experience, one method of reasoning based on reuse past experience was employed, called the Case- Based Reasoning (CBR). The CBR method will allow safety information stored in database to be reused for reasoning process to give safety scores. As CBR works based on stored information from database therefore an image database has to be developed. / Following works (or researches) have been done to overcome problems revealed from preliminary investigation therefore those works have to organize in a structured and systematic system. The research was developed a safety assessment system called SAFE AS. / The safety assessment system worked in two processes, manual calculation and information storage into database. Manual calculation worked as follows: First, a construction practice judgment is given based on image data, safety checklist and using safety scores provided. Secondly, a construction practice is defined into one of two definitions provided: a high-level and a low-level of safety based on Bayes’ Theorem formula and given safety scores. Third, a high-level of safety of construction practice is classified into one of three classifications: most likely safe, fairly safe and most likely unsafe, which are developed, based on fuzzy sets formula. Following manual calculation process, the result from the process then become an input for the second process: information storage. All information of images and their safety practices are stored in an image database. These two processes are done separately and manually. / Problem is arising from manual safety assessment system, that the processes are time-consuming. To overcome this problem, even to make a safety assessment system practically more benefit, the system is developed in a Web-based system, which allows safety assessment process and information storage process done comprehensively and automatically. All users can share their safety knowledge and experiences, and reuse stored experience as a basis of reasoning process from anywhere. / As a result, the research has developed a Web-based safety assessment system to show how to utilize construction images to assess safe construction practice, store information from assessment process, and reuse this information for safety knowledge enhancement. Two experiments using 69 images and a set of detailed images have confirmed the application of a Web-based safety assessment system and verified its reliability. / Another benefit from the safety assessment system is the safety likelihood scores obtained, which can be used to detect safety trends that are developing in construction project over time. These trends were used to predict the likely safety of the construction practices in use on the project in future so it can be used as indicators to monitor and control safety in construction projects. With this process construction images can be used as sources of safety related information and the safety assessment system can be used in future for predicting, monitoring and controlling of on-site safety. / Areas needing future research are suggested, including providing advance search features in the assessment system to retrieve closer relevant cases for case-based reasoning and automated hazard recognition and identification feature to avoid accident occurrence as the result of human carelessness.

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Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Construction of structural concrete frames may take place by using either cast in-situ or precast methods. With the cast in-situ method, these elements are constructed on the construction site as needed. Precast construction on the other hand is more resembles a line. The elements are constructed in a precast yard in a systematic fashion and once completed, they are taken to the construction site where they are to be erected. This study identifies the aspects and attributes which influence the quality of concrete during the construction phase of these two construction methods. The study is independent from the conceptual or design phase. Information regarding these aspects and attributes were obtained from literature and from contractors in industry through interviews and site visits. The literature review also focuses on quality management techniques and factors that influence quality in the construction environment. The information obtained from the site visits and literature was used to design a survey which was sent out to a number of respondents. A comparison between in-situ and precast construction was made based on the results of the survey. The synthesis of the research findings can be used by project teams to help them decide on the choice between in-situ and precast construction. It was found that precast construction is better for durability, and fitness for purpose is less complex for the in-situ solution. Recommendations for future studies are provided at the end of the document. / AFRIKAANSE OPSOMMING: Konstruksie van beton struktuurrame kan plaasvind deur die gebruik van in-situ of voorafvervaardigde metodes. Met die in-situ metode, word hierdie elemente op die terrein gebou soos benodig. Tydens voorafvervaardigde konstruksie aan die ander kant is die konstruksie soortgelyk aan 'n produksielyn. Die elemente word gegiet in 'n voorafvervaardingsterrein in 'n sistematiese wyse, en sodra dit voltooi is, word dit na die konstruksie terrein geneem waar dit opgerig word. Hierdie studie identifiseer die aspekte en eienskappe wat 'n invloed op die kwaliteit van beton het tydens die konstruksiefase van hierdie twee konstruksie metodes. Die studie is onafhanklike van die konseptuele of ontwerp fases. Inligting rakende hierdie aspekte en eienskappe is verkry uit die literatuur en van kontrakteurs in die bedryf deur middel van onderhoude en besoeke. Die literatuur fokus ook op die gehalte, bestuurs-tegnieke en faktore van gehalte in die bou-omgewing. Die inligting is verkry deur ‘n vraelys wat aan 'n aantal respondente gestuur is. 'n Vergelyking tussen in-situ en voorafvervaardigde konstruksie is vervolgens gemaak op grond van die resultate van die opname. Die sintese van die bevindinge kan gebruik word deur projek spanne om hulle te help besluit oor die keuse tussen in-situ en voorafvervaardigde konstruksie. Die resultate dui daarop dat voorafvervaardigde konstruksie beter is vir duursaamheid, maar passing op terrein is minder kompleks vir die in-situ oplossing. Aanbevelings vir toekomstige ondersoeke word aan die einde van die studie gemaak.

La fabrication additive (Impression 3D) consiste à fabriquer des objets couche par couche en utilisant un modèle 3D, un matériau approprié et une machine dédiée. Pour la construction, c’est un nouveau mode constructif qui se profile. Depuis 2010, la fabrication additive a fait un saut technique et médiatique dans ce secteur. Les projets d’impression 3D se sont multipliés et diversifiés avec les premières maisons construites entièrement au moyen de cette technologie (Winsun, D-Shape, Contour Crafting, Apis Cor…etc). Ce travail s’inscrit dans le cadre d’une thèse CIFRE démarrée en 2015 entre le laboratoire de génie civil de l’Ecole Centrale de Lille et l’entreprise Bouygues Construction. L’objectif de ce travail est d’étudier le potentiel de la fabrication additive pour la construction et plus précisément de proposer une formulation à matrice cimentaire qui sera mise en œuvre par impression 3D.La thèse est organisée en trois grandes parties.La première partie est consacrée à la définition de l’impression 3D et des matériaux cimentaires pour définir leurs interactions. La deuxième partie est dédiée à la formulation d’un matériau cimentaire imprimable. L’imprimabilité a été définie par trois indicateurs : l’extrudabilité, la buildabilté et l’adhérence. La troisième partie est destinée à la validation de la formulation proposée. Ce travail peut être considéré comme une première approche pour définir un protocole d’évaluation de l’imprimabilité des matériaux cimentaires à l’échelle du laboratoire ainsi qu’une première étape pour la conception d’une imprimante 3D destinée et adaptée à la construction. / Additive Manufacturing (3D printing) consists in building an object layer by layer following a 3D model. For this purpose an appropriate material, machine and model are needed. From Construction industry point of view, 3D printing is considered as a new building method. Since 2010, the use of 3D printing for construction has known a large evolution. More and more real construction projects are using this new technology. Some of these examples are Winsun in China, D-Shape in Italy, Contour Crafting in California or Apis Cor in Russia…etc.The work presented in this manuscript was conducted through an industrial PhD thesis (CIFRE) which was launched between “Ecole Centrale de Lille” and “Bouygues Construction” in 2015. The objective of this work was to study the potential of large scale 3D printing integration in the construction process and more precisely the development of a printable cement based mix design.The work is organized in three main parts.The first part was dedicated to 3D printing and cement based material as general concepts. Then their interactions were analyzed. The second part was devoted to the printable mix design. The printability was defined using three indicators: Extrudability, Buildability and layers adhesion. The third part was dedicated to check the printability of the proposed mix design. This work may be considered as a first approach to define a laboratory scale methodology for cement based materials printability testing. It is also a step to contribute to the development of construction 3D printers.

To solve the spectrum scarcity problem caused by the high number of wireless applications and users, the concept of cognitive radio (CR) was proposed in the past few years. Cognitive radio networks (CRNs) provide dynamic spectrum access (DSA), where the unlicensed users can access the spectrum without causing unacceptable level of interference to the primary user (PU). DSA was based on conventional spectrum sensing information or geolocation databases. Later, radio environment map (REM) as an improved geolocation database was introduced to enhance the DSA process. It is a comprehensive map consists of different integrated databases, and the interference field information is one of its databases. In this thesis, a description of the REM concept and its construction methods will be presented. The focus will be for the indirect methods for constructing interference map, which represents a layer of the REM. Indirect method refers to the methods that utilize known model information, to first estimate the primary transmitter parameters and then generate REM. Two indirect methods under lognormal shadowing were presented and compared. The better of these two methods is further investigated in different scenarios. These scenarios include different number of sensors, varied size of measurements, several shadowing spread values, different percentages of error in path-loss exponent, and the effect of the number of moving sensors and their speeds to the REM quality. The performance is evaluated using these metrics: “localization error, signal power error and correct detection zone ratio (CDZR). The results show that performance is enhanced as the number of sensors and the size of measurements increase, whereas clear degradation in REM quality is shown when shadowing spread increases or the model parameters are not well calibrated. Also, as the number of moving sensors or their speeds increase, the REM performance becomes less effective

This diploma thesis is a survey describing the relationship that different methods of determination of wear of properties have to valuation of the market price and to the price obtained according to the valid assessment act no. 151/1997 Sb. As a basis for this survey, three family houses of different age were chosen to show the relationships of different methods to prices in various stages of life span of the buildings. All the partial results of the analysis of the different methods of determination of wear of particular buildings were compared with the market and obtained prices. The family houses were assessed according to the assessment act and its relevant implementing decree no. 3/2008 Sb. The valuation of the market prices was made according to the current situation at the real property market in respective locations of the assessed properties.

Kostnad och tid är två parametrar som går hand i hand i näst intill alla sammanhang, inte minst i byggbranschen. Pressade tidsplaner och snäva budgetar kräver noggrannhet och effektivitet genom samtliga skeden i byggprocessen. Framför allt är en kortare byggtid av stor vikt, som ett resultat av det har det industriella byggandet fått en alltmer betydande roll. Syftet med denna rapport är att undersöka lönsamheten vid användandet av prefabricerade element gentemot konventionell platsbyggning. Arbetet har avgränsats till att undersöka ett enskilt område, nämligen lätta innerväggar. Rapporten har gjorts i samarbete med Peab AB och den har utförts på deras pågående projekt, köpcentrumet Mall of Scandinavia i Arenastaden, Solna. De två byggmetoderna har jämförts med avseende på tid och ekonomi. Vidare har de prefabricerade väggelelementens för- och nackdelar samt alternativa användningsområden undersökts. De prefabricerade innerväggarna som används i projektet tillverkas av företaget Elementum Eco AB i Bollebygd. Monteringen av väggelementen sker med hjälp av en modifierad gaffeltruck, vilket är ovanligt. Metoden kräver endast tre arbetare och medför en avsevärt kortare monteringstid jämfört med platsbyggda innerväggar. Metoden är ny för Peab och det är andra gången som de valt att använda sig av den. Det var vid ett tidigare projekt i Tanums kommun, då köpcentrumet Tanum shoppingcenter byggdes, som metoden introducerades för företaget. Efter färdigställandet var erfarenheterna av väggelementen positiva. Man ansåg sig ha vunnit både tids- och kostnadsmässigt och valde därför att bepröva metoden ytterligare en gång. Jämförelsen mellan de båda byggmetoderna har gjorts på två väggar med samma förutsättningar vad gäller dimension och arbetskraft. Fördjupade intervjuer som huvudmetod, egenhändigt utförda inspektioner och litteraturstudie har föranlett resultat i rapport. Resultatet av detta arbete visar att kostnads- och tidseffektiviteten ökar med en faktor på upp till närmare nio gånger, genom val av prefabricering som metod jämfört med konventionell platsbyggning som metod. Flera fördelar påvisas även inom områden som arbetsmiljö och miljöpåverkan. / Cost and time are two parameters that affect one another no matter what the context is, not least in the building industry. Both time schedules and budgets are pushed to the limit, therefore accuracy and efficiency needs to be considered through all stages of the building process. A shorter construction time is of vital importance and as a result of that, industrial building methods has taken a more significant part in the business. The purpose of this report was to investigate the profitability by using prefabricated panels instead of conventional building methods. Due to a given timeframe the investigation has been defined to focus on one special field, namely light prefabricated interior walls. The report was developed in collaboration with Peab AB and the work has been done on their ongoing project Mall of Scandinavia in Arenastaden, Solna. The two construction methods have been compared with respect to time and finances. Furthermore, the prefabricated panels advantages and disadvantages as well as alternative uses have been studied. The prefabricated interior walls, used in the project, are produced by Elementum Eco AB in Bollebygd. The walls are mounted by means of a modified forklift truck, which is somewhat unique. The mounting process requires only three workers and results in a considerably shorter assembly time compared to site-built interior walls. It is a new method and it is used by Peab for the second time. The company was introduced to the method at an earlier project in Tanum, when Tanum shopping centre was established. The over all experience turned out positive and once completed, both time and cost was considered to have been saved. Peab therefore chose to use the method once more. The comparison between the two methods of construction has been made on two walls with similar conditions in terms of size and manpower. The result of this report shows that both time and cost efficiency can increase nearly nine times by choosing prefabricated interior walls compared to conventional site-built ones. Furthermore, benefits in areas such as environmental impact and work environment are shown as well.

Storstadsregionernas växande befolkning, viljan att förtäta förorterna, samt miljonprogrammets stora utbud av standardiserade flerbostadshus i ytterstaden leder oss fram till examensarbetets innehåll: en studie om våningspåbyggnad på miljonprogrammets flerbostadshus. Syftet med examensarbetet är utreda miljonprogrammets potential för en vertikal förtätning. Vertikal förtätning innebär att redan befintlig bebyggelse kompletteras med ytterligare våningsplan. Syftet är även att underlätta för kommande påbyggnadsprojekt genom att lyfta fram svårigheter som ett påbyggnadsprojekt kan medföra, samt beskriva hur en våningspåbyggnad kan utföras. För att nå rapportens syfte ska följande frågeställningar besvaras: 1. Varför ska vi bygga ovanpå miljonprogrammets flerbostadshus? 2. Hur utformas en våningspåbyggnad lämpligast med avseende på stommaterial, byggmetod och installationer? 3. Vad bör särskilt beaktas vid en våningspåbyggnad? Examensarbetet kommer att studera miljonprogrammets potential för en vertikal förtätning i främst Stockholms stads förorter. Flerbostadshusens byggtekniska förutsättningar lyfts fram. Utöver det studeras lämpliga byggmetoder, stommaterial och installationslösningar för en påbyggnad. Examensarbetet avslutas med att belysa vad som särskilt bör beaktas i ett påbyggnadsprojekt. Resultatet av examensarbetet visar att miljonprogrammets flerbostadshus har god potential för en vertikal förtätning. Våningspåbyggnaden utformas lämpligast med planelement av betong om den befintliga konstruktionen tål en tung påbyggnad utan förstärkning. I annat fall konstrueras påbyggnadens stomme lämpligast av planelement av trä för miljonprogrammets flerbostadshus. För att fritt kunna utforma våningspåbyggnadens planlösning bör en balkgrund eller ett installationsgolv installeras. Där kan de nya installationerna till påbyggnaden dras. För att undvika störningar under projektets gång är områdets förutsättningar minst lika viktiga att beakta som den befintliga konstruktionens byggtekniska förutsättningar. Hyresgästernas åsikter och skyddsrumsreglerna ska även beaktas tidigt i ett våningspåbyggnadsprojekt. / The growing population in most Swedish conurbations, the desire to densify housing in the suburbs, as well as the suitability of the so called ”the Million Programme” wide range of standardized apartment buildings in the suburbs, led us to the thesis content: a study on storey extension for “the Million Programme” apartment buildings. The aim of the thesis is to facilitate the concept development phase for future storey extension projects and overall, to investigate ”the Million Programme” buildings’ potential for vertical densification. . Vertical densification means supplying additional floors on already existing buildings. To address the purpose of the report, the following questions will be answered: 1. What are the incentives for building on top of ”the Million Programme” apartment buildings? 2. How should a storey extension be designed conveniently concerning construction methods, selection of structural bearing materials and HVAC? 3. What should be considered especially during a storey extension project? The thesis will investigate potential of the buildings of ”the Million Programme” for a vertical densification, mainly in Stockholm’s suburbs. The residential buildings’ technical conditions will be highlighted. In addition, the study will also consider suitable construction methods and structural bearing materials, as well as HVAC solutions for storey extension. The thesis is rounded off by highlighting what should be considered especially during the storey extension project work to avoid or minimize disturbances during the project. The result of the thesis proves that the ”million programme” apartment buildings have good potential for a storey extension. If the existing building allows a massive storey extension without revetments, the storey extension should be made of plan elements of concrete. Otherwise the most appropriate alternative is proven to be plan elements of wood on the “million programme” apartment buildings. To freely be able to design the plan arrangements in the storey extension, an appropriate alternative is to build a beam floor or an installation floor that creates a space between the existing floor and the new floor. This space can be used for the new installations for the storey extension. Our result also proves that the area qualifications are at least as important to observe as the technical qualifications of the existing buildings. Also the opinions of the tenants in the area and shelter regulations are important things to investigate early in the project.