The project
We were contacted by a long term customer William Hare who use us for our expertise and experience to ensure that they use the best quality products for their structural jobs available.
This project was no different. Especially with it being a key London landmark and the largest most difficult slide bearing application we have attempted. The structure is the 21 Moorefield’s building located above the underground station. The slide bearing is required for a critical jacking operation in which the customer wanted to ensure that there was minimal friction to prevent sheer stress on the steel structures. After this operation the bearing would remain in situ having completed its task.
The requirements: the customer needed bearing that would be able to take a load between 14-18Mpa without yielding. They discussed with us their proposed methods of installing the bearing and requested a quotation for us to complete the works from production to installation. This was not a simple task as the steel plates that required PTFE bonding to them were already welded to part of their final structure meaning that they were now over 2m above the ground, not a dizzying height but certainly one that would face challenges preparing the steel and bonding the PTFE.
After much discussion we advised that there was no possibility of bonding the PTFE to the already semi welded structure. Our design and manufacturing teams came together to devise a solution that would work for both ourselves and our customer. We needed to solve the following.
- Load requirement of 14-18Mps over the total surface area.
- Method of fixing the slide bearings into place to allow them to be effective.
- Design and delivery of the slide bearings within 2 weeks.
The load requirement meant that we narrowed down the slide bearing configurations down to 1 option using our AF115 material which can take a much higher compressive load, around 50Mpa in the recessed design giving a comfortable factor of safety which is always recommended when producing parts for a structure that will have excessive foot traffic.
We now had to come up with the method of fixing the slide bearings into place and delivering the complete bearings within 2 weeks. Through the meetings we found the most effective and economic solution for our customer.
THE BEARINGS
These consisted of 4 sets of plates that would be fixed to the top and bottom plates of the customer’s structure, 2 sets to be held in a diagonal location and the remaining 2 in a horizontal one. The bottom section of the plates shown below. These required a recess to withstand the large load they were going to be under, this raised an additional problem, to machine the plates they would have to be cut into smaller plates to allow for them to fit on our Mills. We got our steel suppliers to produce the overall configuration for us and we then cut these into the required lengths to suit our mills.
These plates have since been sent to the customer and fixed in place ready for installation at the building site. This being one of many examples where we as a company provide effective solutions to complex problems.
