The Glassworks, Back Turner Street

How outside-the-box thinking provided an elegant solution to complicated temporary works requirements

The Glassworks, a stunning new development from Salboy, is nearing completion in the heart of Manchester’s Northern Quarter. Designed with sustainability, health and well-being in mind, this landmark project will provide some of the finest hybrid office space in the Northwest.

Renaissance came on board to help clients Domis and Salboy overcome the engineering intricacies of the build, giving them the tools and support they need to be able to deliver this forward-thinking and ambitious project.

The Glassworks – project specifics

The Glassworks project consists of three interlinked buildings across an extremely tight work site. At one end, a magnificent 18-story glass-fronted tower will provide a modern array of office spaces high up in the Manchester skyline.

Connected to the tower, a pre-existing glass bottle factory is undergoing a full internal restructure, with only the outer façade being incorporated into the new development. This preservation maintains the heritage of the building, allowing the developer to layer modern construction methods with the area’s industrial history.

Finally, a third 5-story glass-fronted building will cap off this truly unique project.

The challenge

Preserving the façade of the glass bottle factory wouldn’t ordinarily cause an issue from an engineering perspective. However, due to the external site limitations of the project, Renaissance was extremely limited in the space available for external temporary works that could support the façade while the interior was demolished.

Flanked on both sides by existing buildings which have basement structures expanding under the street, it soon became clear that an external façade temporary works structure was unfeasible.

After ruling out an external approach, we began investigating the feasibility of supporting the façade via an internal temporary works. We consulted with a temporary works specialist and while the internal approach avoided the issues of the external one, we discovered that the amount of steelwork required for an internal temporary structure would be an environmental disaster. The amount of steel required to support the façade would have eclipsed the amount of steel you would put in the steel frame of that size for a new building.

It was very difficult to justify such a waste of resources both economically and environmentally, not-to-mention completely out of sync with the environmental ambitions of the project.

A different solution was required.

The solution

To provide the supporting works required for the heritage element of the project, Renaissance delivered a truly unique and considered engineering solution.

While the original plan for the development was for a concrete frame to be used throughout, a change of tactic was decided and the building was cut into three independent frames.

By switching the middle section of the building to a lightweight steel frame, a raft foundation was now possible. Without a piling rig driving through the middle, the old frame could be kept in place while the new frame was built, with the eventual demolition performed in stages.

A new raft footing was carefully built around the existing foundations. Cutting small holes in the existing floors allowed the new steel frame to be needled through and around the existing one.

Working in close collaboration with Domis, the existing floors were demolished ‘top-down’, with each floor replaced in sequential order. This intricate dance around the existing frame meant there were always floors ‘grabbing’ the walls, and the temporary steelwork was reduced to a small number of re-usable props.

This method of top-down demolition and sequential construction is believed to be a UK first. By taking this innovative approach, we were able to save 90 tonnes of steel and 75 tonnes of embodied carbon in the temporary works package.

Ultimately, we were able to stay true to the environmental goals of the project while still hitting the brief.

The client’s view

“Renaissance was instrumental in marrying the environmental goals of this project with our plans to preserve the history of the existing structure. Their solution-focused approach and steady support have helped us deliver a truly unique project that will stand the test of time”.

Nick Russell – Salboy

Client: Salboy and Domis
Location: Manchester
Value: £20M