POSTER PAPER PROCEEDINGS

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1 ITA - AITES WORLD TUNNEL CONGRESS April 2018 Dubai International Convention & Exhibition Centre, UAE POSTER PAPER PROCEEDINGS

2 BIM Model-Based Project Management for Optimizing Project Development Insights into the Practical Application at the Albvorland Tunnel Project Wolfgang Fentzloff, Jens Classen Implenia Construction GmbH, Tunnelling Department, Landsberger Str. 290 a, D Munich, Implenia Construction GmbH, Tunnelling Department, Landsberger Str. 290 a, D Munich, ABSTRACT Building Information Modelling (BIM) is a method used to plan and manage projects based on 3D-models. Linking the 3D-models to the dimensions of time (4D) and costs (5D) generates the so called process model which gives rise to a graphic project management tool. In most cases the adoption of BIM stops at the 3D-level. The 3D-model can be efficiently used for considering the various works in the course of realizing a structural building or a civil engineering structure and for the visualization of them. Revealing geometrical clashes in advance takes on greater significance by using clash detection tools. According to the motto virtual construction first then the actual construction interferences in the construction process can be minimized / removed to save time and costs. However BIM is far more than this. The combination of the geometry of the structure with time and costs reveals much more information about the status of a project. From this point on it is not only possible to detect any interferences and the related extra costs and time but to make a prediction of the anticipated consequences in cost and time. 4D-simulations visualize the construction sequences and reveal any clashes. Once the costs are linked to the timeline, a forecast of the expected cashflow in the project can be carried out (5D-simulation) at any time. All three dimensions incorporated in one process model shows demonstratively the progress of the works and/or the project to a planned reference date and allows evaluations with regards the target, actual and forecast. Extracting the relevant data out of the model is a platform for reporting purposes based on any pre-defined key performance indicators. In order to generate this information it is crucial that the project initiator (client) set up a consistent structure in the components of the 3D-model, the activities in the schedule and the items of the BoQ. Moreover the roles and processes must be clearly defined and strict discipline is to be maintained by the acting professionals in order to keep the validity of the Process Model at a high level. Finally tunneling projects are unique when it comes to time and cost tracking, specifically with regard to executing works in an unknown underground environment. The expected geology is based on an interpretation of geological investigations in advance of the works. In the course of the execution deviations are usual. Means and ways to reflect this fact must be incorporated in the process model in an appropriate way and should be agreed to by all parties involved. 2 These instruments are being deployed in a project currently under construction, i.e. the Albvorland Tunnel project, to gain insights into the future use of BIM on largescale infrastructure projects.

3 Key words: Building Information Modelling (BIM); Process Model; Project Management Tool; Visualization; Simulations (4D & 5D); Reporting 1. INTRODUCTION BIM Building Information Modelling takes advantage of the continuous use of a digital building model over the individual phases of the life cycle. This means that the structure is planned with the help of 3D models that allow a lifelike interactive presentation. The models consist of components in which relevant information is stored. In addition to the general information such as geometries, construction materials, etc., the components are also linked to activities from the construction program and to costs from the items of the Bill of Quantities (BoQ), making it possible to make reliable statements on the various completion stages and the associated costs within the scope of project management. DB Projekt Stuttgart Ulm GmbH (PSU) has been commissioned with the planning and technical implementation of the highly complex Stuttgart Ulm Railway Project in southern Germany which is currently one of the largest infrastructure projects in all of Europe. It is broken down into two sub-projects Stuttgart 21 (S21) to rearrange the Stuttgart rail hub and the New Wendlingen Ulm Line (NBS) with high-speed tracks. One of the most prominent structures of the NBS is the double-tube Albvorland Tunnel running in a west-east direction with a length of around 8.2 km; three further tunnels are shorter than 500 m (see Fig. 1). Figure 1. Situation of the Albvorland Tunnel project 2. BASIS FOR USING BIM The German Federal Ministry of Transport and Digital Infrastructure (BMVI), saw the importance of BIM for the near future in terms of digitalisation of the German construction industry and thus released a graduated scheme for the digitalisation in design and construction works in

4 In the meantime, the BMVI is performing research into practical application of the method within the scope of four pilot projects. For example, the Deutsche Bahn is testing the methodology for the Rastatt Tunnel as part of the Karlsruhe Basel project and for the Filstal Bridge of the New Wendlingen Ulm Line (see Fig. 2). Figure 2. Model of the Filstal Bridge Simultaneously one of the German road authorities, Deutsche Einheit Fernstraßenplanungs- und -bau GmbH (DEGES), is deploying BIM for various projects, too. A further funding agreement between the Deutsche Bahn and the BMVI was signed in October 2016 with the aim of supporting various BIM projects. In order to gain more experience with BIM in regards to the large number of highvalue contract awards the PSU took BIM into consideration in other parts of the S21/ NBS project, such as the bridge over the Neckar River in Stuttgart and specifically in one sector of the Albvorland Tunnel. In the case of the Albvorland Tunnel, the first practical experience will be gained with 5D links (linking costs to the 3D model), i.e., cost budgeting, in addition to 3D planning and 4D links to the scheduling. 3. THE SCOPE OF BIM IN THE TENDER PROCESS At the beginning of the design phase, the BIM method was not part of the planning process. Therefore, the design planning was prepared conventionally using 2D planning methods. It was not until the tendering stage that specifications were made as to what the employer intended to implement by means of the BIM method. In order to limit the scope involved, the use of BIM in the Albvorland Tunnel project has been restricted to the west modelling area (see Fig. 3). 4

5 Figure 3. Modelling area at portal west of the Albvorland Tunnel The following structures/ components are integrated into the modelling area: Foundation work, pit excavation work and excavation support (anchored bored pile retaining walls, bulkheads and soldier pile walls) of the preliminary cut with the two western tunnel portals of the new line, the portal of the freight train link s connecting tunnel to the NBS (GZA tunnel) and the portal of the freight train link s tunnel below the A8 federal motorway (GZA-BAB tunnel); General civil engineering work, facilities and third-party roads (service road, rescue area/road), final drainage system, supporting structures; Open track: embankment; Sonic boom structures (mitigating tunnel boom). The client hopes to achieve the following by using BIM: Building-up expertise in handling BIM in large-scale infrastructure projects; Gaining insights into where BIM can generate potential benefits in terms of cost effectiveness; Developing the greatest possible system interoperability, specifically taking the Deutsche Bahn s own systems into account; Facilitating optimization and quality assurance in planning and implementation; Achieving improved communications and exchange of information with project participants; More precise and efficient determination of quantities (also in the event of changes). All the appropriate measures necessary to be successful in the favoured goals, as well as the following defined BIM applications, were set-out in a specific appendix to the tender documents. This can be seen as a first draft version of the Employer s Information Requirements (EIR). The long-term goals are based, among other things, on the BIM objectives specified 5

6 by the BMVI as part of the multistage plan for digital planning and construction. These include, for example, achieving a higher degree of precision in planning and cost certainty as well as optimization of costs during the life cycle. 3.1 The Defined BIM Applications The BIM applications defined in the EIR shall be implemented at the west modelling area of the Albvorland Tunnel; these are outlined in the following D-Assisted Detailing and Coordination for Planning Purposes The application 3D-assisted detailing and coordination for planning purposes contains the generation of a 3D model of the area concerned with all required geometries and objects including the information and properties assigned to them (see Fig. 4). Figure 4.3D model combined with 2D drawings showing land parcels and detailed views Geometry is usually described by length, width, height and diameter. In addition, every component is assigned its own identification number (important for later links), the structure number, information on the material and specifics to tunnel construction, e.g., the tunnel meter, length of one round, driving class, block length and even the pertinent item of the BoQ for linking costs is recorded. The 3D model serves as a basis for planning and on-site meetings as well as for improving communication between the project participants. Potential conflicts can be identified at an early stage and alternatives can then be presented. The conflicts identified at an early stage relate, for example, to utilities crossing the structure (power supplies, telephone lines) that have to be relocated away from the construction area prior to the start of work or anchors that would have led to ill- 6

7 defined situations at places where several rows of anchors would cross each other or even penetrate underground structures. In addition, the 3D model is linked to the 2D technical planning documentation from which the status and overviews of planning packages are prepared according to the target, actual and forecast. Furthermore, the 3D model is used as a basis to determine model-based quantities for plausibility testing of scheduling resources and BoQ-items D and 5D Simulations The 4D model of the BIM modelling area in the Albvorland Tunnel is created by linking the 3D model to the construction schedule. This is used as the basis for 4D simulations, visualizations, analyses and optimization work for scheduling feasibility. Moreover, regular review of the 4D model (this means continual adjustment of the construction processes if they change on account of external influences), evaluations of the construction sequences as well as quantities and resources according to target, actual and forecast. The consequence of continual updating of construction progress is that any impact on the schedule becomes immediately apparent which enables the corresponding countermeasures to be initiated. Figure 5. Examples of visualization of 4D & 5D simulations in the process model In order to generate the 5D model, the 4D model is linked to the pertinent contractual prices contained in the BoQ and the related items themselves (see Fig. 5). If the component-related performance reports are continually integrated into this 5D model it can be used to present and evaluate not only construction progress but also performance levels and costs (target, actual, forecast) for project management purposes in the so-called process model Reporting 7

8 The third application for the Albvorland Tunnel consists of reporting. In this respect, the 3D, 4D and 5D models are used to generate presentations and evaluations of the key performance indicators relating to schedules, costs, performance and planning. One possible visualization can be seen in Fig. 6. Once certain key figures (tunnel meters, cubic meters of concrete, etc.) are specified comparison of target, actual and forecast can easily be presented in the form of dashboard or cockpit views and will allow a quick overview of the status of the project (earned value analysis). Figure 6. Visualization of construction progress according to target, actual and forecast 3.2 Challenges Relating to the Implementation of BIM As BIM is still a recently developed method and as various project participants often do not have sufficient BIM expertise at the beginning of the project or acceptance of the need to use BIM methods has to still be developed in some cases, there is a danger that the BIM method will be pushed to the side during the implementation phase if it is applied simultaneously to conventional planning methods. The active involvement of management and employees alike is vital for the implementation of BIM methods. For this reason, workshops must be held with all participants from the very beginning with the objective of providing support in the various stages of BIM implementation and to present to all individuals involved the potential and advantages of BIM. Furthermore, it is important to be aware of the possibilities offered by BIM and to specify in the call for tender exactly what is expected at what point in time. Due to differences in the levels of expertise on the part of project participants, there are also different expectations. If this is not laid out unambiguously it will be impossible to ensure that participants work with BIM with as little friction as possible. 4. PRACTICAL IMPLEMENTATION OF THE CALL-FOR-TENDER TERMS 8 The project initiator took a courageous and trailblazing step in the call for tender by deciding to deploy BIM for the Albvorland Tunnel after the construction project had

9 already been taken to the tendering stage using conventional planning methods. While this only applies to a sub-area at the West portal it does, however, include all of the main works involved in the project: tunnelling works, civil engineering works, special foundation works, earthworks. This approach makes it possible to process the complex relationships within the scope of preparing a 3D/4D/5D model with the necessary depth of detail in order to gain the desired level of experience. As, in contrast to structural engineering construction projects, BIM had only been deployed to a minor extent in civil engineering infrastructure projects, the Contractor considered it important to not only fall back on its own pool of experience from projects in Scandinavia but also to employ an external team of advisers to develop the general approach and detailed procedures and specifications; this team comprised representatives from think project and AEC3 as commercial enterprises and the Technical University of Munich. Revit was the main software used, among other programs, to prepare the 3D models and RIB itwo for the links to scheduling and costs (4D, 5D). A few other programs such as Desite, Navisworks, Thekla BIMsite are currently being tested with respect to their effectiveness for BIM on the project. The following topics were handled during this process: Preparation of a BIM implementation plan (BIP); Preparation of guidelines and recommendations for modelling; Preparatory work on model structure and model coding; Specification of the level of development and information to be contained in the partial models (LoDs); Use of the shared parameters tool BIM*Q to determine the parameters in Revit families including adjustment on an ongoing basis; Preparation of the process models in RIB itwo to link the construction program to the 3D model; Adjusting the structures of the BoQ (items) to achieve a proper link of costs to the model (5 D); Export of the CPIXML files from Revit using a plug-in to input the data into itwo. In this context, make sure that the software used implements an interface for the standardized data format IFC (Industry Foundation Classes) in order to ensure compatibility of the results from the various programs used. In principle, the challenge coming up in the specific case of the Albvorland Tunnel arose from the fact that the project structure corresponded to the conventional planning process but not to the requirements of the model-based structure. The greatest challenge to be overcome was the lack of a consistent work breakdown structure (WBS) within the project that had to be prepared by the Contractor after the contract had been awarded. The existing structure was adjusted in various steps. Figure 7 shows an example of the WBS adapted to a shoulder of the inner lining of one of the tunnels. 9

10 Figure 7. Implementation of the Work Breakdown Structure The basic setup is designed by identifying an object using information about it. The information goes from general to specific. Finding proper acronyms for each level in the WBS results in a unique code per object, the so-called ID. In this example the ID for the shoulder in a particular tunnel on the left side of the inner lining of section 105# is AVT_WST_TUN_GZA_IL_SH_LE_105. You will find the ID as a property in the 3D model as well as in the 4D model and the 5D model. This system is the crucial backbone in order to be able to generate a realistic simulation of the construction process taking scheduling and costs into account. A further benefit can be achieved for the running phase of the tunnel when RFID tags are implemented into the real objects that again contain the same ID and store the relevant information for facility management purposes (see Fig. 8). Figure 8. Object information stored in RFID tag for FM purposes In addition to this very important WBS issue, many more details dedicated to tunnelling need to be clarified. Besides the challenge of the far more complex geometry of the different structural elements in tunnelling compared to architectural buildings, e.g. fixing tunnel cross-sections along a 3D axis, there are issues related to geology affecting 3D, 4D and 5D (see Chapter 5). 10

11 5. SPECIAL INSIGHTS GAINED DURING IMPLEMENTATION WITH RESPECT TO THE ALBVORLAND TUNNEL One of the most important insights gained is the necessity to train all parties involved to attain the same understanding of how BIM is to be applied. Another important issue is the need for approval or to mutually agree on a processing status for the 3D model as a basis for meaningful project management. The fact that infrastructure projects in general and tunnelling jobs in particular deal with a defined construction material, specifically the ground, does not easily allow the transfer of BIM applications from the more developed routines of architectural building to tunnel projects. Due to fluctuating ground characteristics, it is difficult to make consistent predictions and results in unforeseen surprises over and over again. Usually there is a preliminary ground investigation of the project area to determine the geology, but a certain risk of ground conditions (water, tensions, fault zones, petrochemical conditions, etc.) that cannot be detected is immanent. Interpretation of the anticipated ground conditions are based on sporadic probe drills and other auxiliary information. This knowledge has already been taken into consideration in the project management of tunnelling projects in the past as well as today. Using BIM with its capability to fix, analyse and evaluate project progress, it must be taken into consideration that the described uncertainties require continuous adjustment of the appointed models with special respect to target and forecast. One simple example is the target of the current excavation progress of the tunnel depending on the actual distribution of anticipated excavation and supporting classes. The target is usually defined by a certain probability of occurrence of various classes according to the investigations during the design phase distributed in a percentage assigned to certain advance sections. Time and cost calculations will consider those distributions for the complete tunnel length but has to be adjusted for intermediate reference data. Furthermore, the demands placed on data protection in the institutions involved or, as the case may be, their employees is an aspect that should not be underestimated. There is still a long way to go before 3D planning will be used as the sole basis for model-based project management. 2D planning is currently indispensable if only for the release and approval processes as it is apparent that the technical tools (hardware and software) still do not always fulfil their purpose and further skills will have to be developed among the individuals involved. Furthermore, the third parties that are involved in the approval process (authorities, municipalities, etc.) have not yet reached a stage where they are able to grant the necessary approvals on the basis of documentation prepared in 3D. Changes in the scope of work during the execution phase necessarily evoke an adjustment of either the 3D model or even the 4D and 5D model according to the respective impact. For the time being, it is a common practice that a long time passes between the occurrence of those changes and the willingness to raise change orders accordingly. The significance of any BIM process model in-use will tremendously suffer from the lack of willingness to agree quickly upon changes and their consequences in time and costs for the project. Finally, it is still an ongoing process to test alternative software solutions with regard to the capability of deploying add-ons or plug-ins. Those individual solutions help 11

12 to optimise the software to meet any user requests for creating and displaying specific key figures within reporting processes. 6. POTENTIAL FOR IMPROVEMENT IN FUTURE CALLS FOR TENDER In principle, it is important to differentiate between the planning tasks to be rendered by the individual contractual partners (design and build, sole contractor, general contractor, etc.). In the present case, where the client prepares the design planning, uses it as a basis for the call for tender and then makes it available to the contractor for detailed planning purposes, the contractor should be provided with a 3D model from the client with defined guidelines for offer processing in order to perform a modelbased calculation and to be able to immediately superimpose detailed planning once he should be awarded the contract. The BoQ should be generated from the model and, furthermore, the entire project structure including the activities from the construction program should constitute an integrated whole, enabling the individual components to be linked to scheduling and costs (3D 4D 5D) in a coherent manner for project management purposes. This means that, in the future, BIM will have to be deployed from the very outset of a project. All project participants from the individual trades from the respective life cycles of a structure should be consulted at the beginning of the project in order to define, already at this stage, the respective requirements and needs that, in turn, specify the structure, methods, planning principles, etc. for implementation (see Fig. 8). Figure 9. Scheme of involvement of project participants and corresponding input In this context, it is not only necessary to implement these technical and processrelated constraints but is also imperative to take issues arising from contract law into account. Similarly, the willingness to use BIM on the part of the individuals involved has to be strengthened. 7. SUMMARY AND OUTLOOK 12 The following conclusions can be drawn from the current project progress with

13 regard to BIM: The 3D model must be prepared during the drafting stage and become part of the call for tender. It is necessary to create a uniform project structure (WBS) with regard to the activities from the construction program and the items of the BoQ taking into account the models to be created with their respective components. The check for conflicts using the 3D model is, if employed correctly, a very suitable instrument for identifying execution problems in a timely manner. The 4D and 5D linking, in particular, are challenging issues that require the corresponding systems. In the event that the linking is successful, however, this provides a powerful project management tool. A large amount of detail coordination is necessary between the project participants in order to achieve a uniform understanding of the objectives aspired to in the application of BIM. Regular BIM meetings are a suitable means to this end. When it comes to cost tracking, it must be taken into consideration that costs are defined differently by the client and the contractor. In the event of amended or additional works, it will be necessary to specify within the framework of the construction contracts an unbureaucratic way in which the changes to construction time and construction costs that are generated can be defined in order to be able to fully exploit the possibilities offered by BIM. The provisions of the intended construction agreement have to meet the needs arising from BIM. One issue that has to be clarified is the point at which the project initiator involves the individual protagonists (general and specialist planners, experts, authorities, construction company, etc.) who make their important contributions to the project development, execution and running to which contractual model. BIM is an important tool that, on the basis of models, makes it possible to compile and process a wide range of data within the framework of the progressing digitalisation of the construction industry. The existing structures relating to project handling have to be adapted to the new requirements of BIM in terms of technical, legal and human issues. The technical side of the structural change has been addressed in this report. To the same extent, however, it will also be urgently necessary to reflect on new contractual models and the willingness of the individuals involved to implement BIM. Ultimately, BIM is no longer just a project management method or tool, but rather constitutes a radical cultural change in the development and handling of a project. At this point, we are still in the beginning stages but the great potential and the necessary cultural change are the driving force behind this pioneering work. 13

14 8. CITATIONS AND REFERENCES 1. ASTOUR, H.; SCHÜTT, B.; WÖRNER, C. (2017): «BIM im Bahnprojekt Stuttgart-Ulm - Anwendung aus Auftraggebersicht. In: Paper for the Congress IPDC 2016 (International Planning, Design and Construction) on in Innsbruck, Austria. 2. German Federal Ministry of Transport and Digital Infrastructure (BMVI): Stufenplan Digitales Planen und Bauen, FRAHM, M.; HALLFELDT, Jens; ASTOUR, H.; LORENZ, T. (2017): «Planung und Bau des Albvorlandtunnels mit besonderer Berücksichtigung der Anwendung von BIM. Tunnel 2017/3; pp HALLFELDT, J.; ASTOUR, H.: «Anwendungsfälle BIM beim Albvorlandtunnel». 2. Felsmechanik-Tag. WBI-Print Volume 19, pp SINGER, D; SCHAPKE, S-E (2016): «Modellierungsrichtlinien Projekt Albvorlandtunnel, BIM Consult, think project, AEC ;3 6. BRAUNERT, W: «Albvorlandtunnel, Erkenntnisse und Erfahrungen der BIM-Bearbeitung, Implenia Construction GmbH, Presentation for BIM-Jour-Fixe; FENTZLOFF, W (2016): «BIM in der Ausschreibungs- und Ausführungsphase Erfahrungen vom Albvorlandtunnel Implenia Construction GmbH, Wiener Gespräche FENTZLOFF, W (2017): «BIM Model-based Project Management, Using the Albvorland Tunnel as a Pactical Example» Implenia Construction GmbH, 11th International Tunnelling and Underground Structures Conference 2017, Slovenia, Ljublijana 9. ESCHENBRUCH, K.; LEUPERTZ, S. (2016) :»BIM und Recht ; Werner Verlag, Cologne 14

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