From BIM Journal. Click Here to Read Issue 3
From BIM Journal Issue 03 – here
As part of the London Bridge Train Station redevelopment, Waldeck were contracted to provide the detailed pre-cast reinforced concrete design and deliverables for almost 4000 individual concrete elements across 15 new platforms (9 through and 6 terminating).
The new station is being transformed into a vision of the future creating new platforms for more trains, building a new concourse and creating a bigger, better station for passengers in the fourth busiest station in the country.
The project is being funded by the Thameslink programme – a £6bn Government investment in rail. The redevelopment works is being carried out by Costain and Hyder/WSP on behalf of Network Rail, with the pre-cast platforms being supplied by FP McCann Ltd.
Waldeck were involved at the very beginning of the project during the Early Contractor Involvement (ECI) phase, assisting the pre-planning of the offsite manufacture activities by undertaking concept and scenario analysis within our range of 3D design and visualisation tools. This early stage engagement enabled the Waldeck team to develop innovative solutions to benefit the offsite manufacture and site based handling and placement of the platform units in the most efficient way, whilst keeping to strict site carriage limits and adhering to a tight programme of works.
During the ECI phase, the Waldeck project team utilised an array of analysis and scenario planning toolsets to pre-plan and review designs for the optimal solution of platform configuration and erection. The final output being designed and developed as table and kerb solution to allow a 2.8m long section of platform to being constructed in only 6 individual pieces of concrete. Each section comprised of two tables which sat on two kerb units at the track face to retain ballast, and two slabs spanning between tables to infill. The 3D design optioneering proved fundamental to the overall success of the process and ensured constructability and fit around the steel canopy framework for the roof. This solution however was only suitable for the widest sections of the platforms, the Waldeck project team therefore undertook further iteration analysis within 3D visualisation and coordination toolsets to produce workable solutions for the entire platform configuration, saving time and maximising the standardisation of units overall.
A unique feature of London Bridge Station is the open concourse beneath the live track and platforms. The track and platforms are suspended on a series of large steel frame bridges providing a new challenge to Waldeck. As well as designing pre-cast units to fit into the steel framework, we also had to ensure the solution was able to withstand the impact of a train derailment, punching shear from the physical connection to the steel frame and help insulate the concourse from the noise of 15 live tracks. To address the many constraining factors, Waldeck undertook detailed 3D spatial analysis within the federated model environment to facilitate the bespoke design of an acoustic wall with a ‘joggle’ joint and upstand to form solid connections between the steel frame which were physically bolted to each wall, and the pre-cast slabs overhead.
Whilst standardisation of units were achieved wherever possible, the particular consideration the Waldeck project team had to take into account during the 3D design and analysis stage was the shape of each platform. The unique curves and level changes required to suit the track layouts, meant the majority of all pre-cast concrete slabs were uniquely shaped which posed further coordination implications, all of which were successfully addressed by the effective use of integrated 3D toolsets.
A major function of the Waldeck project team’s role on the project was to work in a collaborative 3D environment, enabling all project stakeholders to effectively and efficiently coordinate their designs to maximise overall project success. Each work stage entailed the approval and release of a package of Microstation DGN 3D models from various stakeholders within the overall design team. The project collaboration management process in-line with BS 1192:2007+A2:2016 was adhered to by all stakeholders and ensured all parties were always working with the latest version of approved project information at all times and was therefore pivotal to the success of the overall project.
Due to the size of the project and number of 2D cast unit drawings required to support the manufacture process, Waldeck developed a 3D design plan to maximise efficiency. The Waldeck project team utilised in-house specialist toolsets to pre-plan and design each unit type (walls, slabs, tables etc.).
To further facilitate and enhance overall project coordination, at defined BIM project milestones points during the modelling stage of each work package, the Waldeck team was required to issue globally coordinated BIM models comprising of all pre-cast elements to the projects Common Data Environment. The main contractors BIM Coordinator was then able to undertake clash detection reviews within an overall federated project information model, providing clash reports to all stakeholders and enable the progressive monitoring and rectification of clash resolution across the entire project. As the Waldeck team also had responsibility of designing and modelling all of the fixtures and fittings required for each pre-cast unit, the BIM coordinator was able to check all of the M&E systems had the necessary supports in the correct locations on top of checking for physical clashes. This was a great benefit to the smooth running of the project by mitigating the need to post fix support systems to the pre-cast units on site.
By working collaboratively with all project stakeholders utilising the project Common Data Environment (CDE), any issues raised during clash detection was assigned as an action to the appropriate party and swiftly rectified before any concrete had been cast, eliminating on-site delays. Without working collaboratively in this manner, adhering to project BIM workflows and processes it would have been hugely time and resource intensive to ensure that all pre-cast elements would fit the unique curves, falls and levels of each of the platforms, as well as the remainder of the stations structure and services.
Accordingly, the Waldeck BIM for the scheme was utilised as a base for all designs and was a key element in Costain winning a national award for the use of BIM from Building magazine. Once clash detection had been completed and all members of the design team were satisfied the work stage was fit for construction, Waldeck carried out a Category 2 design check and formally issued the work stage for construction.
Adopting Tekla Structures allowed Waldeck to model reinforcement within the 3D environment directly into each unit, automatically generating bar bending schedules. Modelling reinforcement directly into each unit also had the added benefit of allowing us to perform 3D coordination reviews detecting reinforcement clashing with cast in fixtures and fittings immediately and make adjustments to bar shape or spacing, mitigating the factory discovering a clash with the reinforcement cage and impacting on the casting schedule. General arrangement drawings and reinforcing drawings where applicable could then be automated for each unit directly from the modelled geometry, allowing a single BIM technician to produce an average of 50 cast unit drawings a week, a huge increase over traditional 2D methods where a 2D pre-cast detailer could only achieve 20-25 drawings a week.
Generating the deliverables in this manner along with a thorough two stage checking procedure on every drawing and schedule produced, allowed Waldeck to provide a constant supply of drawings to the pre-cast factory and greatly reduce the number of factory queries and errors.
The single biggest challenge faced by Waldeck during the project were design changes post approval for construction. The Waldeck project team were provided with the fully federated models of each work package, this allowed any changes which would impact the pre-cast platforms to be quickly identified when undertaking our discipline 3D coordination reviews. As changes were made to the Waldeck models, output deliverables were automatically updated to suit the new geometry allowing for a quick turnaround of revised information to the factory. In a large proportion of cases, changes would be made to units before leaving the factory, and in some cases even before a unit had been cast, vastly improving on site delays.
From BIM Journal Issue 03 – here
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