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Three-dimensional models form the basis for the use of BIM on the building site
The entire world of construction is moving ever further towards model-oriented planning and building. Among the front-runners – and not just in Germany – is the family-run construction company Max Bögl, headquartered in Neumarkt, Upper Palatinate. The company has become one of the largest building, technology and services firms in the German construction sector. In order to fulfill the high quality demands, even in complex construction tasks, partnership-based collaboration with clients, project participants and partner companies is a fixed part of the company strategy. In addition, the use of the latest construction IT and BIM technologies makes an important contribution.
Building Information Modeling (BIM) has for a long time not restricted itself to structural engineering: Thoroughgoing, integrated construction processes – from pre-planning through realization to usage and maintenance – can offer assistance just as well to participants in infrastructure projects, introducing more safety, quality and flexibility in the implementation of the construction task. To drive forward BIM processes actively in the field of highway and drainage engineering at Max Bögl, Evelyn Roßner, who is experienced in the infrastructural field, was given the task, as BIM coordinator, of implementing such thoroughgoing thought processes in civil engineering projects. “Three-dimensional models form the basis for the use of BIM on the building-site,” the expert explains. “They not only bring many advantages throughout the entire planning and construction process, but also make things once apparently impossible, possible,” Evelyn Roßner continues.
Commissioned by the North Bavarian Highway Directorate, the company undertook the renewal of the concrete roadway and renovation of the drainage on an approx. ten kilometer stretch of the BAB A7 highway between the Gollhofen and Uffenheim intersections. For this project, for the first time, the functionalities of the RIB software iTWO civil for pipeline construction, in interplay with the enterprise solution RIB iTWO 5D, were employed. The drainage-specific features of the software were conceived for the demands of such measures. Volume objects in the model form the basis, which are automatically provided with special attributes for cost determination and construction billing. Here, depth steps were considered. In pipeline construction – depending on the depth step – different cost approaches arise for backfilling, for example, or the length of a pipe. The volume objects for the model approach receive corresponding attributes. The height of a chamber ring or the diameter and material of a special pipe can be freely or generically assigned attributes of a drainage project.
Over a period of around nine months, the company constructed, among other things, 20 pre-cast concrete shafts, 115 pre-fabricated plastic shafts, approx. 830 meters of partial soakaway piping and in total around 5,500 meters of multi-purpose pipeline and around 300 meters of reinforced concrete piping. Here, the partial soakaway piping and the multi-purpose piping were installed as a longitudinal drainage below the trough and the reinforced steel pipes as transverse to the roadway to drain the central reservation and as an outlet. The client, who also works with RIB software solutions, provided the information on the existing site in ISYBAU format. Quantity takeoff took place at Max Bögl for the first time with the extended RIB software and was completed within a period of around two weeks. Evelyn Roßner estimates that the quantity takeoff for this kind of measure could be possible in an even shorter time, as soon as all members of the team know the functionalities well and are confident with the BIM program. Once the takeoff is complete, the new data on the state of the road/channel are once again handed over to the client in ISYBAU format so that all extensions and alterations to the drainage after renovation are available.
The client demanded gradations from us of between 1, 1.75 and 3 meters in depth. By hand, this would be practically impossible to bill
“The levels presented a particular challenge,” the BIM coordinator explains. “The client demanded gradations from us of between 1, 1.75 and 3 meters in depth. By hand, this would be practically impossible to measure”, the expert says. An exact height plan would be required here in order to determine which ground layer heights are present in which areas of the drainage. “It would be an immense job and thus a huge time expenditure,” she adds. “However, it is no problem with the iTWO civil solution, because here the formation layer is known and the program calculates all the required heights and depths automatically.”
One clear way in which work changes when BIM models are used in highway or pipeline engineering is the initial added effort needed at the start of a construction project. This has been the experience of this expert from the construction company, based in Neumarkt. This is because numerous working processes are moved to the calculation or project preparation phase: From a rough model in the calculation phase, a more detailed one arises through project preparation to execution, one which is continuously and uninterruptedly supplied with information and further extended towards complexity. Thus, in this early project phase, many aspects are prepared that can immensely reduce the workload in later cycles – for all participants. In pipeline construction, for example, the planned height for the shafts to be built remains preserved to the end of the project.
Even when alterations are made over the course of the project, the RIB program iTWO Civil enters these into the overall process, notifies of all adjustments and makes them accessible for everyone on the site and in the office for whom they may be of relevance. “If we work throughout in a model-oriented way, finished volume objects are used in all subsequent processes of a construction task,” Evelyn Roßner acknowledges. “This optimizes all further tasks for the quantity surveyors and site managers equally.”