Building in a challenging environment
The Panorama Tower construction site is located in the middle of an existing commercial centre in Espoo, Finland. This made it a challenging project logistically from the start.
During the project, a number of new functions in the building information modelling (BIM) environment were implemented in the structural design to improve efficiency in both the site logistics and building cost factors.
The 76 metre high Panorama Tower is an office and business building consisting of three building sections, the highest of which has nineteen floors. The total area of the building is 23,600 m2.
The building has a steel column and beam frame. The bracing frame structures are made of concrete and the lightweight facades are largely made of glass. Construction was completed in March 2008.
- Owner - Varma
- Owner’s consultant - Pöyry CM Oy
- Architectural design - Larkas & Laine Oy
- Structural engineering - Pöyry Civil Oy
- HVAC and electrical engineering - Pöyry Building Services Oy
- Project management -A consortium of NCC and Skanska
- Delivery of steel parts for the frame - ruukki
- Foundation casting and cast in place - Sierak Oy
- Lightweight façade elements - ruukki
• Supplementary steel structures for the facade - Teräsnyrkki Steel Oy
BIM – Interoperable for multi stage use
Structural engineering for the Panorama Tower business centre was based on the building information model. Pöyry Civil Oy used Tekla Structures software and Ruukki, the supplier of the steel frame parts, also successfully utilised the same model. The model was integrated with Staad software to perform analysis related to the building’s stability, horizontal displacement and other design calculations.
In addition, a 4D model, containing schedule information, was used to visualise construction sequence of the project during planning and subsequently at site meetings.
A new development in the design process was the use of separate models of the surrounding terrain and the pit excavated under the building. These were integrated into the BIM which could then be used to share information between project members.
BIM – Identification of design errors and communication of change
‘Thanks to the use of BIM, serious mistakes were completely avoided in the project as the measurement environment was absolutely reliable,’ explained Kari Lassila, Project Manager at Pöyry Civil Oy.
He further stated that ‘the highly visual model based design and the possibility of combining models made information exchange easier, decreased the number of errors, and helped to coordinate the design work throughout the project. The greatest benefit was gained in data transfer between project parties. Ruukki, for example, designed the structural steel components through the model. In addition, model based design helped us to keep to the challenging schedule.’
Pöyry, responsible for structural engineering, created a virtual 3D model of the foundation and frame structures of Panorama Tower early in the process. This model included existing structures of the driveway and service traffic tunnels of the nearby Sello shopping mall. The mall was located under the new tower and needed to remain operational during construction. This had to be taken into account during design.
Due to the high cost of steel and fire endurance class requirements for the building, concrete was selected in the draft stage as the frame material in the 3D model, but was later replaced with steel. ‘Through the model, information was easily exchanged between Pöyry and Ruukki, this helped to quickly implement the changes in frame type and subsequent fabrication, allowing delivery of the structures to the site as scheduled. At Pöyry, the biggest job was to implement the changes caused by choosing steel, which was thinner than the concrete designs for beams, floor and roof hollow core slab sets,’ says Lassila.
Ruukki, supplier of the steel frame, carried out their own design based on the transfer model from structural engineering. The frame model was also updated several times as design work progressed but easily transferred back in the BIM environment. This method of operation ensured the compatibility of the structures and a flawless process from fabrication to assembly. A similar method was used for designing the lightweight steel facades.
BIM – Integrating the terrain model
A groundbreaking feature in the project was the integration of a terrain model. A laser scan of the excavated pit and existing tunnels underneath the building created a surface model from the scan. This was transferred to the structural model to verify the position of the existing tunnels. The building exceeded plot boundaries at several points indicating that the structures were forming obstacles under the pedestrian street. This information meant that structural changes could be made early enough to resolve the problem.
This particular activity from the project has been used to create a thesis on building technology at the Helsinki University of Technology. The objective was to investigate the application of laser scanning as the only as-built dimensioning method to determine the position and shape of an excavated foundation pit for new construction under normal site conditions. It also addressed benefits gained from a 3D volumetric model created with laser scan at the different stages of a building project and throughout the building’s lifetime.
The study found that the point cloud produced by the laser scan can be used to rapidly create cross-sections and calculate approximate volumes directly at the site. This can be transferred to the BIM.
The scan data informs the exact backfill and concrete volumes and the number of form panels required for the foundation base. The scan data also provides comprehensive as-built information for repair and alteration work during the lifetime of the building.
The study concluded that laser scanning is a fast as-built dimensioning method and, within certain limits and clearly defined parameters, it can be used to create dimensionally accurate documentation.
Why Pöyry invests in BIM
‘At Pöyry Civil Oy, using building information modelling for structural engineering requires strong investment and dedicated training of the company and its employees,’ says Heikki Solarmo, Vice President of the company. ‘BIM was introduced in the field of forest industry, traditionally a strong area of construction at Pöyry, some time ago. Since then, its benefits have proven to be so successful in all areas of construction that we have made the decision to move into model-based designing structural engineering as well.’
In addition to the accuracy of the structures and improved design process, further benefits are realised through integration between different design areas within our Group and additional external disciplines such as quantity surveying and scheduling. The features of the model associated with the building’s lifetime are an increasingly important part of our delivery to the client. Pöyry Civil Oy has previously concentrated on the modelling of industrial buildings, so for us, the Panorama Tower project was a natural expansion of modelling to the area of office and business construction.
The model-based planning of Panorama was pioneer work. We now have the capacity to perform the entire design process in BIM, if the client so desires. Even though there still is a lot of room for development, the benefits of modelling are already obvious. In today’s building projects, building information models are being utilised in scheduling assembly, frame erection, and building engineering, as well as property maintenance. There are many possibilities to benefit from and modelling is quickly becoming general practice’.
Why Ruukki invests in BIM
‘Ruukki has a long tradition in building information modelling’, explains Timo Alanko, head of Ruukki’s engineering department. ‘The model is used for managing the supply process. It also forms the basis for the development of processes throughout Ruukki’s supply chain. The model makes it possible to link scheduling with product information and in this way improves schedule management in projects. BIM improves the quality of building. Dimensional errors within plans have been almost completely eliminated.
As BIM becomes more widely used, its benefits increase. Information exchange between project parties, as well as data synchronisation, becomes increasingly important. Because of this, neutral formats for data transfer should be developed so that information from different parties could be brought to common use. To avoid overlapping modelling functions, modelling carried out by the parties should be documented and the information content of the models unified’.