Dipl.-Ing. (FH) Thomas Hauber, Max Bögl 

The magic of a new vision

The team of the Mefisto research project researches the virtual construction site

Virtual construction site with cranes, concrete distributor, wind and fall protection.


The further development of all instruments for construction site planning is decisive

All of the partners involved in a construction project are confronted by a steady increase in complex problems. The problem solution is in addition complicated by unclear connections on the construction site. To keep pace with these problems, the consistent further development of all instruments for construction site planning and controlling are of decisive importance.

The goal: realistic models of the construction site for meaningful investigations

After the use of building information models had become established in many areas, it appeared in principle possible to expand the models of the building with a virtual construction site environment. Our idea of a virtual construction site environment was intended to be modeled as realistically as possible on the future construction site to introduce comprehensive transparency to the construction site geometry and construction processes.

The solution: supplement of the construction model with construction machinery models

The virtual construction site is the consistent further development of the ”BIM” and was expedited with passion and determination. The decisive step on the way to a construction site model is supplementing the construction model with models of the construction machinery required and infrastructure facilities. On the basis of the multimodel system, the construction site can be described by various interdependent specialist models that are independent of each other. Individual elements of the construction site were reproduced from particular perspectives. In the centre is first the construction plot, supplemented by the infrastructure of the construction site and equipment with its dimensions, movement possibilities, performance and cost key data. Ideally, information from other specialist models, such as process models and bills of quantities, can also be included. Depending on what aspects are focused on, various models can be linked as a suitable multimodel. As a whole the investigations have shown that the virtual construction site is perfectly suitable for the construction site planning.

Virtual construction site of a tower block with work platforms and construction machinery.
Representation and calculation of construction site and construction machinery in RIB iTWO.

Publication for all project partners – RIB iTWO as project platform.


Modeling process - overview

All general components of the construction site planning were selected from the newly created construction machinery library and the construction site layout planned in the CAD development environment SolidWorks. The customary application area of SolidWorks is mechanical engineering. Consequently, numerous adaptations were required. The design of the construction site model was then exported via the newly developed CPIXML interface in RIB iTWO. The publication and calculation of the configured construction site model occurred on the project and information platform RIB iTWO. The data exchange between the project partners occurred via standardised multimodel containers. 


Modeling procedure - example

In the example of the tower block a wind and fall protection installation is used as the central safety module. The individual components of the wind and fall protection installation were selected from the newly created construction machinery library. The selected elemental model is equipped with all important information, such as the weight, materials used, the recommended assembly process and the valid assembly tolerances. Fast adaptation of the model geometry to the specific use conditions is possible via the configuration rules. Realistic movement processes of the construction machinery are ensured via the kinematic constraints. If one considers the cranes, the estimate of the range required and the lifting load capacity needed produce the crane types possible. The hook height intended reveals the number of tower pieces required. Together with the suspension or base anchoring, all components are adopted from the library and the crane assembled and configured. Finally the construction model is consistently supplemented with all cranes, scaffolding and concrete pumps needed. This process adheres to defined rules, which evaluate the location and height coordinates and provide the basic construction site layout as a result.

Construction process analysis.


Investigations on the construction site model: visualisation and testing of construction viability

The three dimensionally visualised construction site model offers a good idea of the planned construction task and the planned construction site installation. The configuration of the extremely demanding formwork systems, like an automated lifting raise platform, is in general possible. The number of climbing machines, the lifting process and spatial conditions on the ”production island” can be subjected to a conceptual check.

Collision check and movement analysis

As a result of a considered visualisation of the construction site and emphasis of potential collisions, the decisive overview can be obtained. All crane models used have the specific movement potential of the reproduced originals. In this way investigations on lifting, turning and trolley movement of the service loads can be carried out.


Determination of the equipment performance

Although every construction project is unique, many production processes are similar: the virtual construction site can describe the special production process through the interaction between construction elements, the construction machinery used and the workforce involved. The investigation of the material flows required serves the improvement of the supply security. For example, the consideration of the stationary concrete pump is significant: the pump performance of the concrete pump in this case does not correspond to the standard performance, since the concrete has to be pumped to the top floors of the tower block. The pump performance is reduced by the hydrostatic pressure head and by the internal friction of the unusually long delivery line. The construction site model provides information on the planned concrete pump, the standard pump performance, the exact length of the delivery line with the number of pipe elbows and the actual hydrostatic pressure head. With this information the pump performance to be expected can be determined under real construction site conditions. The pump output determines the specific manufacturing duration for the proper processing of the concrete
transported. (see following page).

Analysis of pump output: pressure head and pipeline length.


Investigation of transport processes

Another example: ensuring the implementation of the formwork across all deployment locations. For this purpose it is necessary to concentrate the formwork as transport units. The path from stripping the formwork via cleaning to the next use is reproduced with typified transport units. This results in a geometric check of the transport routes and crane conveyance. An analysis of the scheduling produces all components that are to be produced in a particular period. In this example the analysis of the quantities was carried out based on a model on the project platform RIB iTWO.

Geometric check of the transport routes of a floor formwork system.


Analysis of construction processes

The analysis of a construction process as interaction between construction work, people, material and equipment provides significant data on the effort involved in the production processes, suitable for subsequent simulations.


Conclusion

The virtual construction site describes our idea of an effective instrument for modern construction site planning. Our vision of the new tool is a realistic multimodel of the entire planned construction site with all of its components and properties: a virtual, three-dimensional construction site model. To allow this vision to be realised all conditions which characterise the construction site should be recorded as precisely as necessary and the tried-and-tested traditions and methods in the construction site planning taken up and further developed. The virtual construction site will only become a meaningful tool for supporting and securing strategic decisions through a meaningful analysis of geometry, crane movements and production processes in the hands of creative engineers. Conceived in this manner, we expect a noticeable increase in planning security.

Rotary tower crane in RIB iTWO.
Construction process analysis.
Material flows in RIB iTWO.



Hoisting and assembly process.
Vision of construction site planning.







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