Stream flowline delineation from high-resolution digital elevation models (HRDEMs) can be problematic due to the fine representation of terrain features as well as anthropogenic drainage structures (e.g., bridges, culverts) within the grid surface. The anthropogenic drainage structures (ADS) may create digital dams while delineating stream flowlines from HRDEMs. The study assessed the effects of ADS locations, spatial resolution (ranged from 1m to 10m), depression processing methods, and flow direction algorithms (D8, D-Infinity, and MFD-md) on hydrologic connectivity through digital dams using HRDEMs in Nebraska. The assessment was conducted based on the offset distances between modeled stream flowlines and original ADS locations using kernel density estimation (KDE) and calculated frequency of ADS samples within offset distances. Three major depression processing techniques (i.e., depression filling, stream breaching, and stream burning) were considered for this study. Finally, an automated method, constrained burning was proposed for HRDEMs which utilizes ancillary datasets to create underneath stream crossings at possible ADS locations and perform DEM reconditioning. The results suggest that coarser resolution DEMs with depression filling and breaching can produce better hydrologic connectivity through ADS compared with finer resolution DEMs with different flow direction algorithms. It was also found that stream burning with known stream crossings at ADS locations outperformed depression filling and breaching techniques for HRDEMs in terms of hydrologic connectivity. The flow direction algorithms combining with depression filling and breaching techniques do not have significant effects on the hydrologic connectivity of modeled stream flowlines. However, for stream burning methods, D8 was found as the best performing flow direction algorithm in HRDEMs with statistical significance. The stream flowlines delineated using the proposed constrained burning method from the HRDEM was found better than depression filling and breaching techniques. This method has an overall accuracy of 78.82% in detecting possible ADS locations within the study area.

Building Information Modeling (BIM) är en relativt ny arbetsmetod i byggbranschen som allt fler företag anammar i sina olika projekt. Med hjälp av BIM kan projektets arbete effektiviseras redan i ett tidigt stadie. Då man till exempel kan utföra kollisions kontroller i skapade 3D modeller de olika aktörerna i mellan redan i projekteringsfasen och på så vis undvika problem när byggarbetet väl har startat. BIM processen består av tre delar. De kallas 3D, 4D och 5D vilket omfattar 3Dmodulering, tidplanering och kostnadskalkylering. I denna rapport riktas fokus på tidplaneringsfasen för att ge en bild av hur arbetet skulle kunna bli bättre om BIM användes för att tidplanera och dess hinder i utvecklingen i användningen av BIM. För att få en uppfattning av hur det var att planera utfördes en jämförelse av Gantt planering och Flowline planering. Där en Flowline planering upprättades från en befintlig Gantt planering för att se hur de olika metoderna skiljer sig åt. / Building Information Modeling (BIM) is a relatively new method of working in the construction industry that more and more companies embrace in various projects. With the help of BIM project work efficiency can be increased at an early stage. For example, I can perform collision checks in the created 3D models of the various players already in the planning phase, this can help avoiding problems when the construction work has started. BIM process consists of three parts. They are called 3D, 4D and 5D and include 3D visualization, scheduling and costing. In this report the focus is mostly on time planning phase to provide a picture of how the work could be better if the BIM was used to planning and its obstacles in the development of the use of BIM. To get an idea of how the planning was carried out as a comparison of the Gantt planning and Flowline planning was made. Where a Flowline plan was established from an existing Gantt planning , then to see how the methods are different from each other.

Det finns stora besparingsmöjligheter i byggbranschen genom effektivare kommunikation och planering. Examensarbetet har genomförts på tre av Q-gruppens byggarbetsplatser i Stockholmsområdet. En ombyggnation/ nyproduktion av lägenheter och lokaler i Saltsjöbaden, en nyproduktion av lägenheter och förskola på Södermalm samt en ombyggnation av lokaler i Folksamhuset på Södermalm. Kvalitativa intervjuer, deltagande observationer och en omarbetning av en befintlig Gantt tidplan till en LoB (Line of Balance) tidplan visar hur situationen med kommunikation och planering i byggbranschen upplevs av platsledning och yrkesarbetare samt hur det kan förbättras. Examensarbetet omfattar två delar där kommunikation mellan platsledning och yrkesarbetare på byggarbetsplatsen är den ena och användning av LoB planering är den andra. Examensarbetet visar att de som arbetar i produktionen gärna ser en kombination av planeringsmetoderna Gantt och LoB. Samtliga intervjuade är överens om att en väl fungerande kommunikation och planering är väsentligt för att projekt ska fortlöpa smidigt. Kommunikationen bidrar till en gemenskap och känsla av delaktighet som är viktig för viljan att utföra ett bra jobb. Därför är det angeläget att sätta den sociala arbetsmiljön centralt, mår man bra gör man också ett bra jobb. / There are significant saving opportunities in the construction industry by having an effective communication and planning. The degree project has been conducted at three of Q-gruppen AB construction sites in Stockholm. A renovation/ new construction of apartments and premises in Saltsjöbaden, a new construction of apartments and nursery school in Södermalm, and a conversion of premises at Folksamhuset in Södermalm. Qualitative interviews, participant observations and a reworking of an existing Gantt schedule to a LoB (Line of Balance) schedule shows how the situation with communication and planning in the construction industry is experienced by site management and skilled workers as well as how it can be improved. The degree project comprises of two parts where communication between site management and skilled workers on the construction site is one and the use of LoB planning is the other. The degree project shows that a combination of the two planning methods Gantt and LoB would be prefered. All interviewees agree that a good communication and planning is essential to make sure that the project proceeds smoothly. Communication contributes to a community and a sense of belonging that is important for the willingness to do a good job. Therefore, it is essential to put the work environment centrally, if you feel good you will also do a good job.

This degree project aims to find solutions to prevent construction process from delay by detecting and resolving work-space congestions and time-space conflicts based on 4D-modeling. The purpose is to improve the work efficiency on the construction site of a hospital project. Through a software experiment, the proposed solutions will be tested to see if the conflicts on the construction site can be resolved or minimized. This is achieved by following the construction phase of the NKS project from Skanska AB. The largest hospital project in Sweden. The theoretical framework focuses on the concepts of 4D, work-space congestions, time-space conflicts, lean construction, last planner system, project organization as well as reviewing a variety of literature regarding how to resolve the conflicts during the construction process. The useful data and information have been gathered through semi-structured interviews with project managers and workforce. The obser-vations have been done on-site. Followed by 4D software experiment, by associating the tasks to the different areas through LBS with the time constraint data, the effi-ciency of work based on the quantity takeoff can be evaluated and thus it allows pro-ject managers to foresee the potential conflicts easily. Eventually, applying 4D - modeling helps the planners visualize the inefficiencies in the schedule and thus re-schedule the tasks before they lead to delays. / Syftet med detta examensarbete är att finna lösningar för att förhindra konstruktions-processen från förseningar genom att upptäcka och lösa arbetsplatsstörningar samt tids- och utrymmeskonflikter baserat på 4D-modelering. Målet är att effektivisera arbetet på byggarbetsplatsen för ett sjukhusprojekt. Genom simuleringar kommer föreslagna lösningar, för att undvika konflikter på arbetsplatsen, att prövas för att få bukt med eller minimera dessa konflikter. Detta uppnås genom att följa byggnadsfasen av NKS-projektet från Skanska AB. Sveriges största sjukhuspro-jekt. Den teoretiska referensramen fokuserar på begreppen: 4D, arbetsutrymmesbelast-ning, tids- och platskonflikt, lean construction, last planner-systemet, projektorgani-sation samt granskning av litteratur som handlar om konfliktlösning under byggpro-cessen. Användbara data och information har samlats in via semistrukturerade inter-vjuer med projektledare och byggnadsarbetare. Observationer har gjorts på plats. Följt av 4D-simulering, genom att sammankoppla uppgifter till de olika områdena ge-nom LBS med tidsrestriktionsdata, kan effektiviteten av arbete som bygger på mängdavtagning utvärderas. Det tillåter projektledare att utan svårighet förutse po-tentiella konflikter. Så småningom kan tillämpningen av 4D-modellering hjälpa plane-rare att visualisera ineffektiviteter i tidsplanen och därmed planera om arbetsuppgif-terna innan de leder till förseningar.

This research endeavor investigated the possibility to combine the visual advantages of both graphical schedule visualization methods, the Linked Gantt Charts (LGC) and Flowline graphs (FLG), derived from the activity-based and location-based scheduling systems, to help resolve some of their shortcomings by capitalizing on their combined strengths. In order to accomplish the goal of the research, a graphical representation system that combines these two scheduling visualization methods, LGC and FLG, is developed. Afterwards, the research attempted to empirically validate the ability of the proposed tool to visually communicate and combine logical and spatial relationships between scheduled activities. This is compared to comprehending the same information by looking at a stand-alone LGC or FLG. The accuracy and time, of deciphering various details of a sample project schedule, are used as parameters to evaluate the proposed scheduling visualization tool, and compare it to the existing LGC and FLG systems. The Hybrid Graphical Representation (HGR) is the tool developed by this research to combine Linked Gantt Chart bars from the activity-based scheduling approach, and flow-lines from the location-based scheduling approach. The HGR concept is founded on the basic idea that both LGC and FLG share a common X-axis, Time. The only difference is in a LGC the Activities are listed on the Y-axis, while the FLG shows Locations on the Y-axis. This research proposed adding a third dimension to the FLG, listing the project Activities on a Z-axis. Viewing the HGR 3D graph from the top, the user will observe the Gantt bars with Time on the X-axis and the Activities listed on the Z-axis. Observing the schedule from the front view, the user will see the flow-lines developed from the location-based scheduling approach with Locations on the Y-axis and Time on the X-axis. After conducting a series of online surveys measuring the time and accuracy of using a prototype HGR schedule, it was found that the users were able to reap the benefits of both scheduling approaches (LGC and FLG), and visually link and communicate information concerning the activities' logical relationships and spatial relationships. However, it took the participants a relatively longer time to achieve that higher accuracy utilizing the HGR tool.

The rapid depletion of hydrocarbon fields around the world has led the industry to search for these resources in ever increasing water depths. In this context, the large diameter (D > 100mm) vertical riser has become a subject of great interest. In this research work, a major investigation was undertaken to determine the two phase flow hydrodynamics in a 254mm vertical riser. Two types of experiments were performed for range of air-water superficial velocities. The first experimental campaign addresses the issue of the two gas injector’s performances (conventional vs. novel design gas injector) in the large diameter vertical riser. The experimental results show that the novel design gas injector should be the preferential choice. The second set of the experimental work investigates the two phase flow hydrodynamics in the vertical riser in detail. The two phase flow patterns and their transitions were identified by combination of visual observations and statistical features. Based on the results, the experimental flow regime map was developed and compared with the existing vertical upflow regime maps/models. None of the flow regime transition models adequately predicted the flow regimes transitions in large diameter vertical risers as a whole. In this regard, the Taitel et al. (1980) bubble to slug flow transition model has been modified for large diameter vertical upflow conditions, based on the physical mechanism observed. The general trends of modified criteria agreed well with the current and other large diameter experimental results. The effect of upstream conditions on the vertical riser flow behaviour was also investigated in detail by two different inlet configurations (i) near riser base injection and (ii) upstream flowline injection. It was found that no significant differences exist in flow behaviour at low air-water superficial velocities for both the inlet configuration, at high air-water superficial velocities, the intermittent flow behavior in flowline influences the riser flow pattern characteristics and thereby controls the riser dynamics. It is found that liquid slugs from the flowline naturally dissipate to some extent in the riser as a consequence of compression of succeeding bubble that rapidly expands and break through the liquid slug preceding it when it enters the riser. The experimental work corroborates the general consensus that slug flow does not exist in large diameter vertical upflow condition. Experimental data has been further compared to increase the confidence on the existing two phase flow knowledge on large diameter vertical riser: (a) by comparing with other experimental studies on large diameter vertical upflow in which generally, a good agreement was found, (b) by assessing the predictive capability of void fraction correlations/pressure gradient methods. The important implication of this assessment is that the mechanistic approach based on specific flow regime in determining the void fraction and pressure gradient is more successful than conventional empirical based approaches. The assessment also proposes a proposed set a of flow regime specific correlations that recommends void fraction correlations based on their performances in the individual flow regimes. Finally, a numerical model to study the hydrodynamic behaviour in the large diameter horizontal flowline-vertical riser system is developed using multiphase flow simulator OLGA. The simulated results show satisfactory agreement for the stable flows while discrepancies were noted for highly intermittent flows. The real time boundary application was partially successful in qualitatively reproducing the trends. The discrepancies between the predicted results and experimental data are likely to be related to the incorrect closure relations used based on incorrect flow regimes predictions. The existence of the multiple roots in the OLGA code is also reported for the first time.

The rapid depletion of hydrocarbon fields around the world has led the industry to search for these resources in ever increasing water depths. In this context, the large diameter (D > 100mm) vertical riser has become a subject of great interest. In this research work, a major investigation was undertaken to determine the two phase flow hydrodynamics in a 254mm vertical riser. Two types of experiments were performed for range of air-water superficial velocities. The first experimental campaign addresses the issue of the two gas injector’s performances (conventional vs. novel design gas injector) in the large diameter vertical riser. The experimental results show that the novel design gas injector should be the preferential choice. The second set of the experimental work investigates the two phase flow hydrodynamics in the vertical riser in detail. The two phase flow patterns and their transitions were identified by combination of visual observations and statistical features. Based on the results, the experimental flow regime map was developed and compared with the existing vertical upflow regime maps/models. None of the flow regime transition models adequately predicted the flow regimes transitions in large diameter vertical risers as a whole. In this regard, the Taitel et al. (1980) bubble to slug flow transition model has been modified for large diameter vertical upflow conditions, based on the physical mechanism observed. The general trends of modified criteria agreed well with the current and other large diameter experimental results. The effect of upstream conditions on the vertical riser flow behaviour was also investigated in detail by two different inlet configurations (i) near riser base injection and (ii) upstream flowline injection. It was found that no significant differences exist in flow behaviour at low air-water superficial velocities for both the inlet configuration, at high air-water superficial velocities, the intermittent flow behavior in flowline influences the riser flow pattern characteristics and thereby controls the riser dynamics. It is found that liquid slugs from the flowline naturally dissipate to some extent in the riser as a consequence of compression of succeeding bubble that rapidly expands and break through the liquid slug preceding it when it enters the riser. The experimental work corroborates the general consensus that slug flow does not exist in large diameter vertical upflow condition. Experimental data has been further compared to increase the confidence on the existing two phase flow knowledge on large diameter vertical riser: (a) by comparing with other experimental studies on large diameter vertical upflow in which generally, a good agreement was found, (b) by assessing the predictive capability of void fraction correlations/pressure gradient methods. The important implication of this assessment is that the mechanistic approach based on specific flow regime in determining the void fraction and pressure gradient is more successful than conventional empirical based approaches. The assessment also proposes a proposed set a of flow regime specific correlations that recommends void fraction correlations based on their performances in the individual flow regimes. Finally, a numerical model to study the hydrodynamic behaviour in the large diameter horizontal flowline-vertical riser system is developed using multiphase flow simulator OLGA. The simulated results show satisfactory agreement for the stable flows while discrepancies were noted for highly intermittent flows. The real time boundary application was partially successful in qualitatively reproducing the trends. The discrepancies between the predicted results and experimental data are likely to be related to the incorrect closure relations used based on incorrect flow regimes predictions. The existence of the multiple roots in the OLGA code is also reported for the first time.