Overlapping design and production through modelling
In the Easton Helsinki project, design was as much about modelling as it was about modelling.
The risks of the Easton Helsinki shopping centre project, which was challenging in many ways, were managed through model-based design and implementation. The client had a clear objective from the outset to implement an accurate implementation model, also to assist maintenance.
The new Easton Helsinki shopping centre in the Itäkeskus district of Helsinki will be built in phases. The first phase is located on the eastern part of the existing K-Citymarket and the parking area. The building will house a new K-Citymarket, other shopping centre space and two levels of ground-level parking. The design followed the client's guidelines and the planner's objectives, such as recognisable local architecture, shopping corridors as part of the area's transport network, accessibility and pleasant and adaptable commercial spaces.
The project was implemented using the project management model of Haahtela-Building Ltd, with the information modelling directly under the project management service. The information model has been extensively used, with exceptionally strong links to a tight schedule overlapping design and production. In this project, design was as much about modelling as it was about modelling.
Jukka Rannisto, the project manager of Byggnadsekonomi's BIM production control, supported Haahtela's organisation and was responsible for scheduling and production information model control. He prepared and monitored site schedules, trained site staff in the use of data models, performed data model-based analyses and quantity surveying, and provided some planning guidance on data models and schedules. The guidelines for coordination have been based on YTV2012, with further refinements where necessary.
"What was special about this project is that I used data models in some way in almost all my tasks," says Rannisto. "The most essential features of the project in terms of BIM coordination were the implementation model, the precise level of coordination, the ten modelling parties, the large scope, and the strong constraints in design and site implementation. Contractors were also obliged to install according to the information models."
The implementation model was the client's intention
"The implementation model was the client's wish," continues Rannisto, who was involved in all stages of the project. "This influenced, among other things, the level of coordination and the use of the data model for installations on site. The implementation data was also fed back into the design on a model basis."
The data model was used very extensively in the project. Rannisto says that it was used at least by the designers, supervisors, contractors, project management, the client and the end users of the facilities.
"In addition to the model-based design work and related tasks, models were used in many ways at different stages. For example, data models were used to explore and develop the final building, plan and schedule work, manage schedule and safety risks, perform quantity surveying and cost control, optimise implementation through various analyses and simulations, perform machine control for civil engineering, and retrieve data required for installation on site."
"The data model was also used to monitor, for example, the supply chain of elements from design to manufacturing and installation in real time, and the information obtained enabled us to react quickly to problems," says Rannisto.
Working within the same model requires a clear agreement on design boundaries
The building's distinctive feature is the undulating double façade of ceramic rods. There are more than 30 000 rods of different colours and lengths, supported by a corrugated steel frame. In order to realise this challenging structure, no alternative was seen other than to transfer information between the parties on a model basis. The corrugated form was designed using specialised 3D design software, from which the information was transferred to the architect's model. This model served as the input for the structural engineer's steel frame design in Tekla Structures. Finally, the contractor carrying out the façade went on to use the model produced by the structural engineer to produce the mechanical design in Tekla. The data transfer went well and the end result was as desired.
At best, the IFC models, updated on a weekly cycle, enabled a rapid flow of information between the parties. For element design, the transmission of source data was even faster and the flow of information was virtually real-time, as the structural and element designers used Tekla's Model Sharing functionality. Due to the tight schedule, working within the same model required a precise agreement on design boundaries, but allowed for a quick response to design changes and source data needs.
"Actual installation data, i.e. the changes made compared to the planned ones, was transferred from the site to the design department using a model-based approach. A lot was learned from the process and it was made to work, but further software development is needed to make the whole process easier," says Rannisto.
The scheduling challenges on the site were solved in many different ways. Traditional resource-based site schedules were created using Vico's Schedule Planner, and the quantities used as the basis for scheduling were obtained from data models. The installation schedule for the frame elements was exported to the element level and fed into the Tekla Structures shared model using Tekla Model Sharing. The site and the element factory also had access to the shared model, which was used to track the scheduling of the different phases.
Assessing the feasibility of changes and coordinating plans would have been impossible without data models
"When the prefabrication design was already underway, a major change was made to the frame by dropping a whole floor (IVKH) to a lower level," says Rannisto.
"This posed many challenges, but we were able to make the changes so quickly that the frame installation was finally completed on schedule. The client felt that this would not have been possible using traditional methods. In addition, many small changes were made along the way as more tenants came into the shopping centre and the plans were completed for a variety of reasons. Assessing the feasibility of the changes and coordinating the plans would have been impossible without the data models."
"The IV machine room, which was changed in the middle of the design, was indeed such a big change that it would not have been possible to implement it within the given timeframe if everyone had not worked to the same model," says Anne-Mari Kuoppala, Project Manager at Ramboll, which was responsible for the element design. "The misunderstandings were avoided largely thanks to Tekla Model Sharing. In hindsight, we are very pleased that sharing was dared to be introduced at an early stage. Of course, as this was the first shared modelling project for many parties, the approach required some growing pains and learning. However, we were able to agree well on design boundaries and roles. Such approaches are bound to increase, and rapid-cycle planning is something we need to be prepared for. Rapid change will become the new normal, but the quality of plans must not be compromised by time constraints. It is vital that information models are coordinated by a single person responsible to ensure that they are of maximum use later in the life of the building."
The combination of regular model reviews and coordination meetings helped to manage the challenges posed by the pressure of change and design constraints associated with construction. Contrary to the general practice in the industry, the information model coordinator worked directly under the project management, which gave the client and the project management an objective view of the state of coordination of the plans. The design needs could be presented more clearly to the designers from a site perspective, which facilitated the allocation of resources to the right tasks.
Lujabetoni supplied all the precast concrete elements and steel structures for the frame, designed and installed. "From our point of view, the model-based schedule tracking helps significantly to understand the overall picture compared to traditional methods," says Samu Mäkelä, Information Model Coordinator. "Anticipation is much easier with comprehensive schedule tracking for all parties involved. The model allows us to visualise the production situation compared to installations without Excel spreadsheets or reports. In this project, everything that was in the model was correct. The model was used for design guidance and on site to identify elements and retrieve images. The collaboration went well and Tekla Model Sharing speeded it up, especially for the elements."
Lujabetoni intends to further develop the role of the data model coordinator and integrate modelling tools into the production management system developed by the company. Easton Helsinki's schedule tracking system can be used, for example, in a future hospital project. In addition, Lujabeton is developing modelling components such as the Luja-Superlat component.
Pile site of the year 2015 and winner of Tekla BIM Awards
During the civil engineering phase, Tekla's accurate pile modelling brought benefits to the planning of pile work and pile deliveries. The earthworks contractor utilised Tekla Structures ' positional information of the boreholes in the excavation work so that a separate level indicator was not required in the borehole installation. The data fed into the excavator, together with the excavator sensors, allowed the bucket to be accurately guided to the required excavation levels around the sensor holes. The groundwater drains were modelled with trenches, which made it possible to ensure, for example, that the reserves passing through the continuous sensor lines were placed in the correct position.
The scale of the project, the tight schedule, careful pre-planning, good communication and cooperation, and a well-managed site meant that the challenging ground conditions made the project the 2015 Pile Construction Site of the Year. The designers accurately modelled the pile lengths based on test pile driving, which ensured accurate and error-free pile deliveries. Based on the pile dimensions, the necessary additional piles and augmentation of the anchorages were modelled. Visibility was one of the best modelling benefits of the major project.
According to the Tekla BIM Awards jury, the Easton Helsinki project made extensive use of information modeling and model data throughout the construction process. The project partners felt that in this project, design equated to modelling and the use of the information model was also used extensively by the subcontractors. In addition, the client made use of the information model, the benefits of which in design development and decision making were taken up to the client's clients. From the outset, the contractor's objective was to have an implementation model for the maintenance of the building. The jury's view of the winner is summed up in the sentence "Easton Helsinki won a tough competition by a user".
Installation data of the model with the on-site viewers
The contractors' supervisors clarified the issues in advance in the office, and workers have taken installation data from the model on site using software such as Tekla Field3D and Trimble Connect. The review of solution options, hole rotation, installability checks and many other design tasks were carried out on a model basis. The architect and the data model coordinator carried out systematic checks both between the design disciplines and internally for each. For the first time, the HVAC designer used VR glasses to check the installability of pipes and ducts in IV machine rooms. This proved to be such a successful solution that it was extended to other projects. Communication of data model reconciliation was handled using BCF files and a cloud-based tracking tool.
The frame implementation options were compared using Tekla Structures and Vico Schedule Planner, using the element weights and locations from the model. This allowed the optimisation of the frame lifting method in terms of schedule and cost. The simulations in Tekla enabled a more accurate verification of the installation sequence and the necessary modifications. This allowed the installation to continue uninterrupted throughout the project. For example, the installation schedule was updated when the planned installation quantities of cavity slabs were found to exceed the available transport and production resources at any given moment. The entire supply chain of elements was monitored by sharing a snapshot with Tekla Model Sharing, and challenges were responded to quickly.
The requirement for a delivery model for installations carried out exactly as planned led to contractors using the model to carry out the works. The combination models maintained on site have been used in particular for TATE installations. The height, size and location data, as well as the surrounding other technology, were of interest to the installers. The elements were checked for BEC data exported to IFC files and for installation details. The implementation model objective was achieved because the overall picture of the dimensions and installation site was sufficiently outlined using mobile device viewers.
The project piloted a method whereby installation deviations from the plans, or "red pen marks", are exported back to the plans using a data model. During the project, different approaches were experimented with and Tekla Field3D was used.
The parties involved in the project
Client: Kesko Corporation
Project management service tasks: Haahtela-rakennuttaminen Oy
Architect: Lahdelma & Mahlamäki Architectural Office Oy
Structural design by Wise Group Finland Oy
Element design: by Ramboll Finland Oy
HVAC, sprinkler, refrigeration design: Granlund Oy
Framework contractor: Lujabetoni Oy
Data model coordinator and production scheduling: byggnadsekonomi Oy
Project in numbers
Gross area approx. 65700 brm²
Around 5600 elements, 40 km of piles and the same amount of facade cladding
About 32 km of cable trays, 400 km of cable, 15 km of ducts and 57 km of pipes
