The LEAN experts from ZÜBLIN Ground Engineering are making their debut in the new airport tunnel construction project at Stuttgart Airport: for the first time, the team is testing an in-house developed LEAN concept. “With our new methods, we can identify the steps in the construction process that are critical for performance and visualise the entire process development,” explains Diego Bellato, Head of Digitalisation and Process Management at ZÜBLIN Ground Engineering.
During the test run, the construction process is recorded directly at the point where the value is generated using a combination of work sampling studies and time sampling studies. Based on this potential analysis, for which Diego Bellato’s team also programmed an app, continuous analyses and adjustments, as well as target/as-built comparisons of the various construction activities, are carried out. Production planning and control (PPC) is generated in this way, taking into account the trade-specific
cycles and incorporating the real data coming from the construction site. The experience gained in this way can, in the future, offer added value, for example in the tendering and execution phase, and expand the know-how in the application of LEAN methods in ground engineering.
Step I: Value stream mapping
The value streams are identified and visualised on the basis of an overall process analysis (OPA). For the construction of a bored pile wall, for example, the production of each individual bored pile and the sequence, number and duration of the single steps in the process can be analysed. The determination of the time required is based on the technical properties of the equipment used, but also on the experience of the construction teams at the site. Each step of the target process is assigned to one of three categories: value-adding (1); not value-adding, but necessary (2); or waste (3).
Step II: Collection of process data
With an in-house-programmed potential-analysis app, the production data (as-built data) can be recorded at the construction site and stored in the database of ZÜBLIN Ground Engineering together with the target processes and duration. The recording of the production intervals is uncomplicated: the worker selects the predefined activities at the actual time of execution in the app and the corresponding time stamp is stored in the database in real time. Site managers and authorised project participants can access this data at any time.
Step IV: Implementation of production planning and control
The statistical evaluation of the recorded as-built data and previous target/as-built comparisons enables a failure mode and effect analysis (FMEA). Early recognition of risks allows improvement measures to be initiated at a proper time. For this purpose, potential errors are recorded and evaluated with a risk indicator, according to their probability of occurrence and detection. Production planning and control (PPC) is set up on the basis of the determined value streams, the actual construction processes, the collected data and following analysis. The aim is to communicate and record possible deviations from the target performance in weekly and daily plans in a timely manner. These changes are adjusted in the above-mentioned plans and controlled regularly. This, along with the results of the production control methods, is discussed weekly by the construction team at the site.