Expertise in large projects, partnering, BIM and Lean: the keys to success

Over the course of a project, a partnering model offers many different levers to help manage and execute the work involved. But a great deal of advance preparation is required to sort things out with the client, architect and the in-house team, to clarify expectations and to bring all the different elements together into an effective whole. Partnering also depends on goodwill from all sides, trust, a lot of time, and a lot of discussion. We look at the Südcampus Bad Homburg project to see how the two-stage partnership process works in practice.

As requested by the customer

Fortunately, Wüstenrot, Implenia’s client on this job, is familiar with the idea of partnering. The tender process was already divided into two stages: Wüstenrot explored the opportunities for partnering with several general contractors, but ultimately liked the model offered by Implenia’s Major Projects branch best.

Following Expo Real 2018, Implenia was only too pleased to take the opportunity to present itself and its partnering model. The team from Major Projects and Design Management impressed the client with a clearly structured, proven partnering model. Implenia began contract negotiations with Wüstenrot and in spring 2019 signed a two-stage agreement.

Phase 1, the pre-construction phase, included the various planning and approval steps up to bid submission, while phase 2 covered detailed building design and the actual construction work.

HOAI service phases 1-4* were handled by the architectural team selected by both parties and hired by Wüstenrot. The Major Projects branch handled all the other specialist planning as well as overall coordination. A large team made up of client, design managers, architects, specialist planners and builders worked together to formulate and optimise the building specifications, the dimensions of the new buildings and the desired product standards. The development process was regularly supported by the branch’s calculation team and realigned whenever reliable indicators suggested it was necessary.

This all took a year and a half before building approval drawings were completed in summer 2020. The resulting diverse mix of homes would necessitate a further large investment of time in the next phases of planning.

Project work needs good communication

Construction plans were already divided into separate plots for the building approval drawings, and these were sent to the authorities for approval.

Developing and building a new urban neighbourhood together with all the associated access logistics is a highly complex business. Mastering the challenge in this case has only been possible thanks to regular workshops with the right experts, active coordination with the client in planning meetings, and the early involvement of an experienced operational construction team and the calculation department. A collaborative approach, mutual respect and a clear focus on a common goal were vital here.

One special feature of the Südcampus project is that Implenia worked with its planners and architects right from the start on all the service phases and actively took over management of the whole process. Supplemented by structural engineering planning from its own Building Engineering specialists, Implenia worked through the phases in constant consultation with the operational team. The big advantage of this is that everyone was heavily involved in the project and familiar with its details even before the final designs were completed, before offer calculations were made and well before actual construction begins.

Owing to the size of the project, the detailed building designs – service phase 5 according to the HOAI* – took several more months to complete. In this phase too, close collaboration is needed between everyone involved in planning and construction; the relevant product manufacturers also need to be brought into the process. Thanks to our team’s expert guidance, detailed issues could be resolved effectively from both the technical and commercial perspectives as part of the ongoing Value Engineering approach. The BIM model plays a crucial role here especially when it comes to the definition and quantification of building elements and materials. The resulting data is being used to produce service specifications and directories, as well as for calculating the required quantities of concrete, steel and other material, and for timetabling.

Putting together and coordinating the Implenia team

Our project managers and cost calculators have played key roles right from the start, bringing their experience to the tendering and execution process at the earliest possible stage. The design managers are also crucial: they have already been through the planning phases on many projects and also know all the interfaces and possible weak points from the operational side. The success of any project depends to a large extent on the core competences of planning and execution management.

Kolja Schmidt, design manager and head of internal technical services at the branch, has been a constant throughout the Südcampus project, playing a key role from the start. Alexander Korth, senior project manager, and his execution team were also actively involved in the planning and tendering process.

Digitalization in action

BIM was not contractually required by the client, but all the planners involved worked with modelling and were willing to collaborate on a BIM execution plan from an early stage. Models were regularly exchanged and discussed via a common platform provided by Implenia.

The architects’ models also served as a foundation for the model-based offer calculations, so there was no need for the branch to make a new model; it could just develop and analyse the existing one.

The plan for the actual construction phase is to use mobile devices to make the latest drawings and associated models available to the construction site team at all times, wherever they may be on site. In addition, BIM-based quantity take-offs should make it easier to tender for and pay for subcontractor services, and to make item lists for day-to-day construction work. There is also an interface to Lean Construction: service requirements and quantity specifications from the model are linked to the Lean Construction takt-time plans, for example.

The plan, the method the realisation

If a project is to be brought to a successful conclusion, it is vital to give some thought right from the start as to how all the complex activities on the construction site will be coordinated with each other to ensure a smooth work flow. Construction time and the use of repeatable methods and processes are big themes for the Südcampus project. With seven separate plots, some of which are being built on simultaneously, it takes a huge amount of advance planning to ensure the different trades mesh efficiently, materials are used when they should be and supplies are delivered on time. Lean methods help with the planning of processes and timings, and of construction site facilities and logistics, which is why it is so important for the Lean team to be involved early on.

Overall project manager Alexander Korth, decided to use the advantages of Lean Construction to optimise control of the project and ensure its success. He invited the Lean team to conduct workshops with project workers about the individual stages of construction, from earthworks to bracing, to the various building construction tasks.

Process and deadline planning will ultimately include subcontractors as well. To help ensure the success of the project, these will be invited to regular meetings so they can actively help shape and share responsibility for construction processes. Experience from other projects shows that this can contribute significantly to a smoother construction process and more relaxed handovers.

*HOAI: Germany’s official fee scale for services provided by architects and builders. This scale identifies nine “service phases” also known as construction phases. By defining these phases, the HOAI breaks down the overall services rendered in the course of a construction project and serves as a basis for the fees charged.

How BIM was incorporated into the project

General:

  • The client does not stipulate any BIM requirements
  • Through early involvement in the pre-construction planning also early entry into the HOAI service phase 2
  • All planners involved work with modelling, often using the same authoring software that Implenia uses (Autodesk Revit)
  • This allows early integration of PES-BIM to control and coordinate the model-based planning

Planning phase:

  • Planners and Implenia volunteer to use BIM in this project and to exchange models with each other regularly right from the early planning phase
  • The aim is for everyone involved to have rapid access to the latest plans at all times, to minimise interface losses and to support communications and the flow of information within the planning team
  • This required a BXP (BIM execution plan), which clearly defines the rules for collaboration between everyone involved in planning (architects / structural engineers / TGA planners)
  • The BXP was produced by PES-BIM and the planners together, and continuously adapted to requirements
  • Regular review of the BXP by PES BIM to check e.g. whether rules about localisation and structure were being adhered to
  • Implenia set up the process for model-based conflict control and issue management early on and implemented this with all the relevant planners.

Offer calculation:

  • The models produced by the architects also served as the basis for the model-based offer calculation. This meant there was no need for Implenia to create a new model. It simply checked the architects’ models, aligned them with Implenia Content and analysed them in iTWO.

Detailed building design phase:

  • The plan for this phase is to use the benefits of the BIM method to help the construction site team
  • By using mobile devices loaded with the Dalux Field app, site workers will be able to access the latest drawings and associated models at any time, even when they are away from the site office. This will also make communication with subcontractors easier.
  • In addition, the Desite software can produce model-based quantity take-offs to help with ordering materials and invoicing. Meanwhile, Revit can generate colour-coded overview plans for subcontractors
  • Desite is also linked to Lean and the takt-time planning; this is supported by “4D reports” (model-based scheduling per calendar week).

The “Südcampus” residential district in Bad Homburg certainly qualifies as a major project:

 27 apartment blocks, a creche, seven underground car parks with a total gross floor area of approximately 80,000 m2 on a site of approximately 40,000 m2.
Building target: 540 apartments, creche, underground garages
Start of construction: planned for end of 2020
Construction period: 38 months