Knowledge-Hub
Knowledge-Hub

181 Talgarth Road

London, United Kingdom
Industry
Construction
Sector
Urban Living
Building Type
Hotel
Building Elements
Concrete Frame, Isolated Ground Floor Slab

The Project

Developed by Dominus and designed by Rogers Stirk Harbour + Partners this development is made up of student accommodation and a 400 room hotel to be constructed on the former site of the West London Magistrate’s Court. The project had been on and off for years but eventually started in earnest in December 2022 when Whitby Wood, with whom we had successfully delivered a number of projects in the past, contacted us asking for support with the building vibration isolation system design. 

 

Key value we brought to the project

Aside from the quality and performance of the system we provided, the key value we provided was speed. We were highly reactive right from the start, fielding questions and developing a design that, based on experience, considered the critical aspects and constraints of the project. This tempo continued right through detailed design, manufacture and supporting the contractor throughout the installation. 

Dominika Maciejewska
Project Manager
181 Talgarth Road development will always stay in my mind because it was my first project acting as Project Manager. With my 3 years of Application Engineer’s experience at Farrat, great support from the main Engineer, Adriana Leotta, and the entire Production Department I could really enjoy working on this complex but swift moving project. One of my favourite tasks were site inspections where I could check the installation progress and see how our work during the design and production stage turns into a real building in centre of London.
The site is bounded to the north by Talgarth Road and the eastern approach to the Hammersmith Flyover, and directly to the south by the District (12 trains per hour each way) and Piccadilly (24 trains per hour each way) London Underground Lines as they approach Hammersmith Station to the northwest. The hotel operator’s requirement regarding re-radiated noise from railway trains not visible from the bedroom window when measured at the bedhead shall not exceed 30dB LAF,max. The acoustic consultant RBA Acoustics’ vibration analysis predicted that the typical worst-case levels were up to 48 dB LAF,max meaning the building vibration isolation system need to achieve a reduction of nearly 20 dB LAF,max which from experience from previous projects was highly achievable with a well designed and constructed 8Hz system.
The rest of the development, including the 10-story part of the hotel, was deemed to not require vibration isolation.
On first impression it is perfectly reasonable to assume, as the contractor, HG Construction did, that this is wasteful and overly expensive because the ground floor did not need isolation. However, when viewed holistically, the additional cost to isolate the ground floor using Farrat’s innovative VFT System, would be less than the costs involved in: 1. Restraining each column in case of notional horizontal loads and disproportionate collapse whether isolated at the top or bottom of the column. 2. Allowing differential movement between the isolated columns and non-isolated ground floor slab whilst maintaining fire protection, waterproofing and thermal insulation. 3. Acoustically isolating every interface between the non-isolated ground floor and the isolated first floor slabs including façade, services, internal walls, fixtures and fittings etc. And then policing their construction throughout the project to ensure no bridging has been created.
Once all avenues had been explored it was agreed to proceed with this design. Since it was a multi-building site, the contractor could concentrate on other buildings in the development to allow time to design and manufacture the building vibration isolation system.
Farrat and Whitby Wood worked intensively and collaboratively to incorporate the vibration isolation system into the structure. Starting with identifying the key structural nodes of columns, cores and shear walls and then undertaking the load modelling process to integrate the LNR acoustic bearing spring stiffnesses into the structural load model. Once the LNR bearing design was fixed, the next stage was the lateral restraint design using Farrat’s standard 700kN VI Shear Key to resist all shear loads passing along the core and shear walls.
With the positions and types of each element now designed Farrat’s team created detailed setting out and installation instructions for the LNR Bearings, VI Shear Keys and VFT System in order that the system could be installed by the contractor without the need to a specialist installation team.
Following an accelerated manufacturing programme, materials were delivered to site within 6 weeks of the design being completed. Here we see 700kN VI Shear Keys and LNR Failsafe Assemblies delivered and ready to be installed.
Farrat VFT System delivered to site.
A Farrat 8Hz LNR Failsafe assembly ready to be grouted in place. The unit comes with lifting eyes for easy movement and placement on site and levelling screws in each corner to minimise installation time and avoid fiddly shims. The steel plates above and below the LNR bearing helps spread the load into the concrete reinforcement.
Levelled and grouted LNR assembly with VFT System laid around it onto which the ground floor slab’s thermal insulation is laid.
Levelled and grouted LNR assembly with VFT System laid around it onto which the ground floor slab’s thermal insulation is laid.
8Hz VI Shear Key levelled and grouted with VFT System laid around it and the thermal insulation in the background.
General view of the construction methodology.
In the advanced stage of installation with the thermal insulation laid onto which the gas membrane and waterproofing (yellow) is laid ready to receive the ground floor slab.
During installation of the reinforcement for the ground floor slab. In the bottom left of the image you can see the rebar constructed around the shear and tension studs protruding from a 700kN VI Shear Key. This image nicely demonstrates that once the floor slab is cast the entire building is isolated and construction can continue without worrying about follow on trades bridging the building vibration isolation system.
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