Innovative delivery models attempt to deliver major construction projects within budget and on time. However, proving their efficiency is difficult because of a missing base for comparing innovative and traditional delivery models. Therefore, a common ground is mandatory, as given in the "Gemeinschaftskraftwerk Inn" (GKI).
Part of the GKI is a 23.5 km long headrace tunnel. The excavations started in the design-bid-build model with a unit price contract, which was terminated during construction by mutual agreement. The alliance contract was chosen to continue the tunnel advance with a new contractor. Only key personnel was exchanged. That allows a unique direct comparison of both delivery models.
A probabilistic analysis was conducted. In principle, probabilistic models of the excavations were introduced to compare the construction time in the two different contract models.
The key finding is that the construction time is 15 % to 22 % faster using the alliance delivery model.
Traditional delivery models like unit price contracts often fail to fit the needs of major projects. These models exceed the budget, and projects are not finished on time. Therefore, innovative delivery models are commonly regarded as a solution and a better approach to project delivery (Sander et al. 2022). Even though these innovative models have been used more frequently in recent years, comparing both models is complicated: projects are only realized in either of these models.
During the construction of the "Gemeinschaftskraftwerk Inn" project, both models were applied. This research project aims to define a common basis for analyzing the different contract models and determine the main points of the contracts that cause delays. On this base, a comparison of the two contract models was conducted to evaluate the efficiency of the alliance contract.
The project "Gemeinschaftskraftwerk Inn" (GKI) is a hydroelectric power plant. Owners are the Tiroler Wasserkraft AG (TIWAG), with a share of 86 %, and the Engadinger Kraftwerke AG, with a share of 14 %. It is located at the Austrian and Swiss border and has been operating since the 4. November 2022. The yearly production is 440 GWh with a total capacity of 89 MW.
