REPURPOSING HISTORIC RAIL INFRASTRUCTURE
Camden Goods Yard was the first London terminus for freight rail traffic between Birmingham and London. This historic site is being repurposed and transformed by St George into a multifunctional development featuring housing, office space, shops, cafes, and artisan-maker workshops, a rooftop farm-to-fork restaurant, and a supermarket.
Morrisroe have been appointed to deliver the basement and superstructure.
CUTTING DOWN ON…PROPS
To optimise the construction process, Morrisroe approached Conquip to review the existing propping design and to provide a leaner, more efficient solution.
Our in-house temporary works team were thrilled to collaborate with AJ Morrisroe again, following successful past projects at Marylebone Square and the UCLE Marshgate.
Our team reassessed the existing piling wall design, carrying out their own geotechnical analysis to determine whether the number of props in the original design could be reduced.
The results were impressive! The new temporary works design significantly reduced the number of props from 20 props across 2 levels, to just 6, on a single level.
SUFFICIENTLY BRACED FOR THE CHALLENGE
The main challenge our team faced revamping the temporary works design was to reduce the two-level scheme to just one level of props…not an easy feat. Recalculating the loading on the pile wall proved to be a significant step towards achieving this.
We carried out a full geotechnical analysis and we came to the conclusion that the pile wall was stronger than estimated. The result was that we were able to reduce the number of props and support the pile wall with just one level of horizontal props.
Irene Viloresi | BIM Technician, Conquip
This enabled our team to confidently reduce the number of props and propose a simpler, more efficient design, while remaining within deflection limits of the scheme. Weekly monitoring reports of inclinometers in critical pile locations gave the team assurance that the analysis was on the right track.
Switching from raking props in the inherited design to a knee-brace propping provided more operating space on the ground, enabling the site team to carry out the basement work (building the slabs and liner walls) more easily and work freely under the props. Knee brace propping also eliminates the need for any remedial works. (Raking props would have required areas of the intermediate floor slab to be boxed-out to allow the raking prop to pass through. These ‘holes’ in the slab would have had to be ‘repaired’ once the props were removed.)
The new engineering design enables us to complete all our basement works with no obstructions and eliminates any return visits to site to fill in any infills of slabs or pockets. Also, safety-wise, it allows us to remove the props ‘blue sky’ rather than trying to get another temporary works in place to aid with the prop removal.
Hassan Jeylaani | Project Manager, AJ Morrisroe
IT’S IN THE “SMALL” DETAILS
Our solution used a double stacked waling beam for part of the wall. As the manufacturing tolerances for the modular waling beam sections can be within +/- 5mm, when they are double-stacked, the alignment between the top beam and the bottom beam can differ, especially when they span a long pile wall, like in this project.
To overcome the challenge of transitioning from a double waling beam stack to a single, a somewhat unconventional solution was required. This connection is pretty tricky as the connections between the beams must be incredibly accurate, the final pin connecting the two beams must be within a couple of millimetres.
To achieve the perfect alignment on the connection between the two waling beams, we incorporated a recently launched waling section that, with the use of additional shims, could be adjusted to compensate for the manufacturing tolerances. This section provided the required accuracy to transition from a double-stacked waling beam to a single waling beam. Different – yes, innovative – yes, surprising – no, it’s what we’re renowned for!
This innovative component effectively compensated for the fabrication tolerances, contributing to the overall success of the project.
CONTRIBUTING TO IMPROVED PROJECT OUTCOMES
The new temporary works design benefitted the project in many ways.
Fewer props, less cost. The new design reduced the overall hire cost, thanks to reduced prop numbers and reduced project duration.
REDUCED CARBON EMISSIONS
Lower impact on the environment. Fewer props meant fewer inner-city deliveries and lower CO2 emissions, improving the project’s carbon footprint and reducing the impact on the local community.
Increasing the operating space it made the construction process, including machinery movement and basement access a lot easier and faster.
A COLLABORATION SUCCESS
We were delighted to provide AJ Morrisroe with a temporary works scheme that made vast improvements to the efficiency of the Camden Goods Yard project and allowed the construction team to take advantage of Conquip’s experience and support.
Plenty of experience with Conquip propping. Props have always been very good, they’re easy to fit, and easy to take out. Conquip’s back-up behind the scenes is very good as well. The experience with the Conquip team was second to none and they helped us all the way through.
Barry O’Sullivan | Construction Manager, AJ Morrisroe