Move BIM to site Bouygues UK - Tower Hamlets Town Hall

Author: Simon Hall

Operating in the UK for over 20 years, Bouygues UK has progressively grown its business in the sectors of building, infrastructure and industry. Bouygues UK focuses on sectors where it is particularly well-positioned to add value through its technical expertise, skills and experience, drawing on the talents of the wider global Bouygues Group. They are an innovative business with a diverse workforce, which underpins how they approach their extensive project portfolio. Their philosophy of knowledge sharing, adopting best practices and embracing new ideas ensures they consistently deliver the highest quality projects to their clients. By drawing on the heritage and support of the Bouygues Group, which operates in over 90 countries, their local expertise and focus on intelligent, competitive delivery, twinned with the resources, reach and backing of their parent company that gives Bouygues UK the edge, delivering work with passion, flair and innovation.

Tower Hamlets London Borough Council is the local authority for the London Borough of Tower Hamlets in Greater London, England. The Council was created by the London Government Act 1963 and replaced three local authorities: Bethnal Green Metropolitan Borough Council, Poplar Metropolitan Borough Council and Stepney Metropolitan Borough Council.

About the Project

The Tower Hamlets Town Hall (THTH) is a Grade II listed building, the site of the former Royal London Hospital. It is one of London’s oldest historic landmarks and has been at the heart of the borough’s history since it was opened to patients in 1757. London Borough of Tower Hamlets acquired the building in 2015 and began redevelopment work to convert the building as the new Town Hall and headquarters for the Council. The new town hall will provide a total of 26,700m2 of civic office space, including an open-plan office space on the upper floors.

“At its heart will be a community feel with a café, outdoor spaces, and an idea store. Whether you want to host a meeting, borrow a book or get involved in what is happening in your neighbourhood, the town hall will bring people together and make Tower Hamlets a better place.”
John Biggs – Mayor of Tower Hamlets

Challenges

Working in the environment of a Grade II listed building comes with its own unique set of challenges.

The need to protect both the heritage of the site was paramount to Bouygues UK, as was the working environment, including an emergency helicopter flight path above; a London Underground tunnel below; a combination of busy roads and party walls around the site and the proximity of two large, working hospitals, the Royal London Dental Hospital and the Royal London Hospital. Throughout the project, Bouygues UK employed methods intended to achieve both goals.

“As part of our continuous improvement, innovation is key to our business. The digitalization of our industry and the very demanding BIM Level 2 requirements of our Tower Hamlets Town Hall Project have been the drivers for us to look at implementing new ways of working.”
Jerome Magnier - Project Director, Bouygues UK

Implementation

Before any construction work began, Bouygues UK designers created 3D BIM models generated by several software of various disciplines. The BIM models are primarily used for coordination and problem detection between the disciplines involved in the project.

For a project of this scale, engineers would ordinarily need to use on-site all the 2D information generated through a BIM model to turn the virtual project into a real construction site. It is from these models that all the 2D data, such as plan views, sections and elevations, are generated. The layout of the virtual project on site was made by engineers and surveyors using the 2D information for office preparation and setting out. With the pre-existing 3D models, Bouygues UK could use them for the setting out and construction instead of using the 2D data.

To achieve this objective, Bouygues UK choose the Leica iCON System.

“With their proposed new technology, Leica were offering the opportunity to bringing the digital BIM model to the construction site and using it on a daily basis during the works. Not only this has helped to streamline a complex process of managing the information, but is has helped ensuring the accuracy of the information provided to site, directly extracted from the model. A special contribution to the design and installation work of the MEP in the reconversion of the old Royal London hospital. With our investment in this technology we increase quality, reduce errors, save time and also contribute to reducing our carbon footprint.”
Jerome Magnier - Project Director, Bouygues UK


BIM Model to Site Bouygues and Leica Geosystems

The solution consisted of a robotic total station and a portable computer with special software to handle the BIM model and connect with the total station. The system used International Foundation Class (IFC) files, which can be read, edited and understood by the most popular software used in the industry.

“We knew that we wanted to bring the model to the construction site, we knew that the technology was available. So, we looked for and found the Leica iCON system that seemed to meet our expectations. Bouygues UK management decided that Tower Hamlets will be the project to try this approach and after a year of implementation, we can say that the system corresponded in full of what we expected from it at this stage. It was undoubtedly a winning bet”
Antonio Santos – Civil Engineering Chief Surveyor, Bouygues UK

The BIM Manager published the latest models in the server into a local folder. The models were created in Revit Format, Navisworks format or IFC format. After receiving a notification by mail saying that new updated models are available in the CDE folder, Bouygues UK engineers would access the folder and retrieve the model in IFC format, which would later be used in the iCON System.

After the upload of the IFC files, Bouygues UK proceeded with the quality control. The quality control consisted of ensuring that the setting out is made with the same standards of the traditional processes, checking the quality and accuracy of the model inside the iCON system by cross-checking with the 2D drawings. The 2D information is gathered by the engineers in charge of the drawings and comes from 4P and delivered to the Survey Team. The selected latest IFC file is retrieved from the CDE folder and uploaded into the iCON system.

After selecting the point, the portable computer will connect with the robotic total station and start the setting out process automatically. Until this point, no 2D information was needed and the staked points were recorded for future documentation for quality purposes and verification reports. In the retaining building, Bouygues UK used the potential of this system by managing to set out the builder works on the vertical elements, such as walls, using the capability of the system to calculate the intersection of the existing wall with the Builder works axes on site.

All types of inquiries were made directly on the model, including dimensions, lengths, heights, points, areas, volumes, type of materials, and others depending on how the IFC model was generated. This information could be shared by anyone on site who needed it.

Advantages

• The advantages of this solution were immense:
• The designers saved time in the creation of 2D information
• The contractors saved time in the printing of 2D information
• The drawing revisions were facilitated and some even needed
• The entire project could be viewed, not just the 2D element
• Errors were dramatically reduced during the transposition from the 3D model to 2D information and from 2D to site
• With the model on-site, anyone was able to access the data needed
• A significant reduction of the Carbon Footprint by using less paper, ink, plastic and other products related to the physical drawing production
• The possibility of using the model in conjunction with total stations, robots and site virtual reality created new forms of setting out and visualization on site

“To be able to receive the latest version of the project from the BIM team and after half an hour go to the construction site and start the implantation of columns, walls, slabs, metal structure or MEP services in a precise way is remarkable. Of course we took our precautions to check the liability of the system to guarantee the quality of the construction and also we count with our strong BIM department that create the conditions for this to happen. It is not only the time we save but also the decrease in the possibility of making mistakes, and once in the field, you can check your work against the model immediately, do verifications, produce as built and send it back to the office or BIM team. Even our supervisors and team leaders in the site ask to see the system and put questions about the design.”
Antonio Santos – Civil Engineering Chief Surveyor, Bouygues UK

Setting out these elements on vertical walls required a special set of elevation drawings, plan drawings, and schedules. The models saved the design team a lot of time and effort, allowing Bouygues UK to begin the works much sooner. The process of preparation almost disappeared and setting out was quicker and more accurate. The innovative technology from Leica Geosystems proved that the arrival of a 3D model on-site into the daily activities of the RC production was one of the great jumps on the project, especially on the engineering surveying side by side with the apparition of the calculator machines, computers, cad software, Total Stations and GPS. The solution will also improve the collaboration between the design and construction teams with updated and site-friendly reliable BIM models.

“We do not need to do any preparation in the office as the software creates the points for us. The IFC Models from the designer are flagged with red and green points. We receive approved models with specific information and only approved points”
Antiono Santos – Civil Engineering Chief Surveyor, Bouygues UK