Due to their unique character building projects are associated with relatively high uncertainties and are characterized by various exogenous and endogenous influences. A special branch of the construction industry is tunneling or respectively pipe jacking. In this sector various factors need to be considered, like the heterogeneity of the ground (= geology) and the general site conditions such as space, accessibility, topology or climate. The capacity of a pipe jacking project is considerably dependent on the capacity of individual processes, in particular on the capacity (= speed and frequency) of the soil excavation process. In order to ensure efficient work and thus the optimization of the productivity of the overall project, it is very important to reduce the number of the many time- and resource-intensive downtimes. Among the main causes of these downtimes are poor planning, waste (of time and resources), the missing of helpful tools and the behavior in unplanned situations. Structural disturbances are among the largest sources of loss regarding the execution of construction works. In order to establish a productivity optimization, the known occurring processes were structured and various tools from the lean area were implemented. The productivity-optimization is done in three steps. The first step is concentrates on the value-generating processes and also their sequences are optimized. The second step also considers optimization of the support processes as well as the dependencies of all plannable processes. The lean thinking methods and principles, which come from the automotive industry, is focused on continuously improving the productivity by reducing waste within the processes. Several of these techniques have already been adapted to the construction industry under the name Lean Construction and most of these techniques start with the first two steps. However, the third step, in which additionally the unplanned disturbance processes are taken into account, is hardly considered, although it does have great potential for increasing the productivity. For this reason, the process model developed in this thesis is concentrating on this third step for the better part and is therefore detecting processes, particularly during standstills, which can be executed parallel to the standstill-causing process (and which may also cause a standstill in the near future), under the consideration of the current conditions of the project like the duration, the resources, the space or the noise. A stoppage is caused either by a necessary support process or a disruptive process. Once a stoppage and its reason are identified, it is determined whether the parallel execution of other processes during this process is possible and with regard to the entire project, makes sense. The aim of this is that once the disruptive process is resolved, the scheduled value-generating processes can continue as long as possible without any further disturbances. For this purpose, the processes whose parallel execution is possible are identified on the basis of predefined criteria. If several processes are parallel possible, these processes are sorted by certain filters which are regarded by their future influences. The process model thus is a decision-making tool for the responsible site staff, which provides reasonable suggestions for further processes. The functionality and applicability of the process model is verified on a pipe jacking project. Both, the flexibility and the adaptability as well as the intuitive use of the model in real use could be shown.     «

Due to their unique character building projects are associated with relatively high uncertainties and are characterized by various exogenous and endogenous influences. A special branch of the construction industry is tunneling or respectively pipe jacking. In this sector various factors need to be considered, like the heterogeneity of the ground (= geology) and the general site conditions such as space, accessibility, topology or climate. The capacity of a pipe jacking project is considerably de...     »