Calculation of precast elements as an introduction to BIM

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1 Building Information Modelling BIM Calculation of precast elements as an introduction to BIM BIM is the integrated process of planning, building and managing, supported by a consistent digital building model which is accessible to everyone and which integrates all geometrical and descriptive information in a component-oriented way. The basis of the process is a 5D model which, in addition to the 3D geometry, contains the component costs as the fourth dimension and the time flows as the fifth. BIM is an international trend in the building industry. In building construction in particular, appropriate models are used for various tasks such as calculation, visualisation and status report. A number of software producers offer tools for the creation and evaluation of BIM models. The use of BIM is compulsory in some countries. Wolfgang Ehlert, Ingenieurbüro für Bauinformatik, Germany Jochen Hanff, ceapoint aec technologies GmbH, Germany Drawing Model BIM is neither a product nor a certain software, but a method. The BIM Guideline for Germany [1] states: The central advantages of the BIM method are considered to be the quality, currentness and transparency of project information, which can be evaluated at all times and leads to greater security with regards to costs, deadlines and sustainability in the handling of the project. One of the essential features of this method is the re-use of information between the individual sub-processes and task areas. The models can be used, for example, for the determination of the quantities for the calculation and for the quantity survey for the scheduling. The great benefit here is that different structures can be determined efficiently from the model for different tasks. Model-oriented vs. drawing-oriented The fundamental difference between the model-oriented working method and the traditional drawing-oriented working method is the data models, which illustrate The data models for the BIM method offer more than a pure 3D representation objects with their essential properties and save them not just as lines and text in a drawing. The data models for the BIM method thus go beyond the pure 3D representation of a building. The information, for which the I in BIM stands, is therefore not the 3D geometry, but the properties of the objects. Changed processes and new fields of activity BIM models can be used, for example, for the determination of the quantities for the calculation and for the quantity survey for the scheduling. Costs Deadlines, process management Presentation BIM enables a new type of co-operation between different project participants. This co-operation involves the exchange of models, giving rise to dependences through the forwarding of information between the participants. Information prepared in one place is re-used in another. Due to these dependences the processes of planning and executing a building task are changed. The activities that traditionally take place to a large extent in parallel are networked by the re-use of information. Amongst other things this also affects the time at which an activity can be carried out. This change in the process of planning and execution is of particular importance and is the deciding factor in many cases as to whether the use of BIM is successful or unsuccessful. When deciding on the use of BIM in a project or in the company, therefore, the change of processes must be particularly observed and taken into consideration. The change of the processes and the use of new tools result in new demands being placed on the participants in a building pro - ject. It is generally assumed that new fields of activity or career profiles also arise as a result. Particularly worthy of mention here is the task of BIM co-ordination, the purpose of which is to ensure the flow of information between the individual disciplines. This task requires extensive organisational skills and technical knowledge. The BIM co-ordinator ensures that the necessary information is 24

2 Dr.-Ing. Wolfgang Ehlert (1951) studied civil engineering in Bochum and has worked in the precast industry since 1988 (10 years in CAD, since 2001 in ERP). Dr.-Ing. Jochen Hanff, CEO of ceapoint aec technologies GmbH. ceapoint aec technologies GmbH from Essen develops products and offers consulting for model-oriented work in the construction industry. The company was founded in 2010 by Dr. Jochen Hanff, who had worked for many years in notable companies in the construction industry. During that time he concerned himself intensively with Virtual Design and Construction and was involved in a large number of BIM projects in Germany and abroad in the context of this activity. This enabled him to get hands-on experience of the use of BIM and the requirements in different projects. jochen.hanff@ceapoint.com present in a model and available to the participants. In order to do this the BIM co-ordinator needs to know the tasks of the individual participants in addition to having a technical understanding of the possibilities and limits of the software tools and file formats employed. BIM use in Germany and model availability In Germany BIM has mainly been used so far in the field of building construction. However, innovative building contractors are also starting to use it in other areas such as underground construction or the planning, production and assembly of precast elements. Overall, however, the use of BIM is still uncommon and a great deal of action is needed to implement the BIM method practically and efficiently. In particular in the early phases of a building task, the challenge lies in the timely production of models that possess the necessary degree of information while the expenditure for their production is nevertheless justified. The production of 3D models as part of the production of plans by specialised planners and the timely provision of these models to the building contractor is unfortunately the exception rather than the rule. An essential requirement for BIM is thus not met. A further consequence of this is that the quantity survey, as the basis of the calculation, still takes place in the conventional way on the basis of more or less accurate plans. The advantages of a calculation on the basis of a 3D model are obvious, however. Essentially these are: Efficient calculation of the costs by means of the automatic determination of the calculation parameters from a suitable 3D model Visual representation on the interactive 3D model and thus increased security in the calculation: You have to see what you re calculating Visual representation of planning, production and assembly status on the 3D model Quantity survey in the precast plant For the aforementioned reasons, amongst other things, it is still predominantly the state of the art in precast plants to use markers with different colours from the available general arrangement drawings for the quantity survey in order to ascertain the quantities of the various precast elements. Afterwards a parts list is created as the further basis for the quotation, for which the dimensions (parameters) of the various precast elements are taken from the plans. The actual calculation then takes place on the basis of this parts list. Calculation in the precast plant The calculation of structural and architectural concrete components takes place on the basis of the single geometry. So that the prices of the various precast elements can be determined with sufficient accuracy but with minimum effort, despite differing geometries, parameterised sample parts are used in the Betsy precast concrete element ERP system, which can similarly be supplemented by parameterised modules such as recesses and corbels. This system offers the option of visualising the calculated parts as a 3D diagram and thus of graphically checking it. For common precast elements, open source software is used to generate parameterised 3D sample diagrams which can be adapted by the cus- SAA Engineering Automation Technology for Concrete Precasting Plants Count on our Support team SAA Engineering GmbH Gudrunstraße 184/4, A-1100 Vienna T:

3 Fig. left: conventional markers with manual entries and overlaid software result markers Fig. right: elements in status colours (yellow = plan exists, green = produced) with display of position, assembly sequence number and target delivery date tomers to plant-specific needs. Further 3D samples can be created by the customers using the same means. Quantity survey with software marker and 3D model creation An A0 plotter stands in most precast plants today, although unfortunately only very few works have their own technical office. The works receive the plans as PDF files and print them out themselves. Even if the plans, which are thus in digital form, are not always free of contradictions or complete, they form the basis together with the method described below for a new-type quantity survey and a simple way of creating 3D models. In place of the coloured markers on the paper, a software marker can be used in the PDF plans with Betsy. Sections or elevations of the 3D diagram of the precast element are placed in the respective PDF general arrangement drawing and counted at the same time. The placement of a column in a top view is done with a single mouse click, while with a double click the start and end points of a beam or the left and right upper corners of a flat part can be determined together with the corresponding dimensions at the same time. By clicking (referencing) on marked points of already recorded components, the dimensions can be recorded with sufficiently high accuracy, but can also be changed and supplemented easily in the automatically created parts lists. Due to the placement of the elements in the general arrangement drawings as described above, not all position coordinates of the parts in the building model are obtained. However, these can be added in the fields provided in the parts list with a minimum of effort. This type of quantity survey gives rise to a) the parts list with main dimensions for the calculation. b) graphical linkage of the calculated elements with the position on the PDF plans. c) a 3D model. d) a possible entry into BIM. Advantages a) The numbers of items are correct. b) In the case of an order, the graphical linkage of the elements with their positions in the plans permits amongst other things the fast assignment of assembly sequences as an entry into the planning of assembly, production and planned delivery. c) The 3D model can be used to show the customer what he is going to get, since the model can be displayed by free software on PCs, tablets and smartphones. d) You no longer have to hope that you will get a 3D model from other people at some time in order to gain BIM experience. The model and the object data (quantities, prices) can be transferred to the ceapoint desite MD BIM information and visualisation system ( and can be used there, for example, together with BIM data from Autodesk Revit and Tekla Structures and other CAD systems. Perfection of the 3D model The 3D model created by the software marker is helpful and sufficiently accurate for the quantity survey and the calculation. For presentation purposes, however, a reworking of the model is required. Betsy provides a number of tools for this that do not require an extensive user interface and are therefore quickly learnt. The results of individual steps can be checked graphically with desite MD. So that this rework can be performed very comfortably, Betsy makes intensive use of the ceapoint desite MD bi-directional interface. Objects can be added, shifted and removed via the interface. In this way it enables the direct, interactive control and changing of the individual 3D elements and the entire 3D model from Betsy, as in a CAD system. However, the 3D model should not and cannot replace a CAD program. Visualisation and evaluation of models Apart from the interactive visualisation of the components for the calculation, the current production and assembly status can be illustrated in the model. To do this, the 3D models can be displayed on PCs, tablets and smartphones using free software 26

4 It is possible to retrieve the properties of an object in the 3D model at the push of a button Coloured representation in the model. The distinction between produced and non-produced components is shown here ACTUAL data for production and assembly are imported from Betsy and evaluated in desite MD. desite MD offers various functions here for grouping objects, colour-coding them and evaluating their properties. The properties of an object can be retrieved at the push of a button and it is easy to isolate a partial model according to certain criteria. 4D simulation (3D model & time flow) If the objects are linked with activities, then the course of the building progress can be animated with the model. On top of that, any desired properties of the objects can be evaluated over time. These are typically properties such as costs or materiai, but can also be properties such as crane or machine requirements. Thus questions of logistics can also be investigated with the model. Forwarding and re-use of models INDUSTRIAL DESIGN CONSULTANTS SPECIALTY & RETROFIT CONTRACTORS enterprises of ROBERT OBER.com ROBERT OBER & ASSOCIATES, LLC The models created in this way can be exported from desite MD. In addition to the geometry of the objects they also contain their properties and can be used in principle for further BIM applications. Communication between the project participants plays a major part in the BIM method. For this it is necessary to forward the models to partners and to allow as many people as possible to access the information contained in the model. The ceapoint desite SHARE software is avail

5 Literature [1] BIM-Leitfaden für Deutschland, Endbericht des Forschungsprogramms ZukunftBAU, ein Forschungsprogramm des Bundesministeriums für Verkehr, Bau und Stadtentwicklung (BMVBS) Auftragsforschung/3Rahmenbedingungen/2013/ BIMLeitfaden/Endbericht.pdf? blob=publicationfile&v=2 4D simulation and evaluation of resources over time. The course of the costs over time is shown here. Forwarding of models using the free ceapoint desite SHARE software able free of charge for this purpose. This software is limited to the essential functions and has an easy-to-use graphical user interface. Hence, the interactive models can also be used by persons who have little or no experience of CAD programs and who are not used to handling models on the computer. Summary Whereas a complete 3D model from CAD has until now usually only been available after the completion of all working plans, the method described permits the advantageous 3D use at the start of the implementation planning as well as the production and assembly planning. The new software marker from Betsy and the extensive bi-directional connection between Betsy and ceapoint desite MD enable the immediate use of BIM for precast element designs. With the help of the multifaceted analysis and visualisation options in desite MD, the models can be evaluated quickly and simply and the constant visual check increases the security in the calculation and, in the case of manufacture, in all planning processes. The production of a 5D model and the interactive visualisation improves communication between the project participants and creates a basis for further applications of the BIM method in the execution of a building project. FURTHER INFORMATION IBB Consultants & Engineers Ingenieurbüro für Bauinformatik Vor den Feldern 17, Köln, Germany T , F ehlert@betsy.de, ceapoint aec technologies GmbH Max-Fiedler-Str. 6, Essen, Germany T , F jochen.hanff@ceapoint.com, 28