Creek Road Technical Case Study

Darren Higgins

o Well served by public transport, there is access to DLR, national rail, river boat and several bus routes which provide quick transportation to central London and surrounding areas.

o Town centre provides several facilities including restaurants, pubs and shops.

o Local attractions include Greenwich Market, Cutty Sark and Greenwich Park.

o Numerous schools and colleges nearby including University of Greenwich.

o Short distance from Canary Wharf and the O2.

Creek Road - Site Location

Creek Road – Townhouseso Townhouses located to south of site

are family homes which form the boundary to a nearby park.

o An intimate mews space is created between theses houses and the rest of the development.

o Quite streetscape will provide pedestrian route to town centre with car parking for owners.

Concrete Formwork Construction

o Technique used by contractor Bouygues in the construction of Creek Road, Greenwich involved using a combination of a bespoke vertical panel system specifically manufactured in France for Bouygues UK alongside a lightweight horizontal panel system.

o Both these systems are modular however they are different to tunnel form systems which requires a very specific building typology.

o This method allows for the construction of a more aesthetically pleasing design whereas tunnel form construction is suited to a repetitive stacked design.

o The construction sequence must be split, casting vertical and horizontal elements separately (generally by core) as the systems are not designed to be used simultaneously.

Bespoke vertical casting system manufactured for Bouygues UK in France (Images: Onur Osman)

Horizontal and vertical formwork systems in place(Image: Luciano Vitello)

Concrete Formwork Construction

o A crane is essential to the construction sequence as it is needed to lift the formwork into a vertical position for it to be restrained using props.

o Site operatives can then fix reinforcement and ties against the erected formwork.

o If services/openings are required they can also be accommodated at this stage.

o The opposing face of the formwork is then positioned at the correct distance by using wedge clamps which will also hold the two panels in place.

o Concrete is then poured and once it has hardened sufficiently the formwork is stripped, easily cleaned and moved to the next position.

Left, view from crane across site(Image: Bouygues UK)

Below, crane jib snapped in high winds from Storm Katie, Easter 2016(Image:Darren Higgins)

Concrete Formwork Construction

o The process of positioning and setting up a full rig can take the majority of a day.

o If complete and there is adequate time left to supervisor a pour the concrete can then be cast.

o The concrete is left to harden and set which can take up to 3-4days, once set the formwork can be struck and positioned into its next location. This process is to be repeated until all vertical members in the core are cast.

o Recent innovation in formwork has led to the development of several different types of small lightweight modular systems that offer versatile formwork solutions on site including lightweight horizontal panel systems.

Lightweight horizontal formwork system erected / Workers laying reinforcement from above / Reinforcement in position awaiting concrete pour (Images: Luciano Vitello)

Concrete Formwork Construction

o The unique feature of using the Creek Road construction technique was that all external, party walls and cores were cast in-situ as shear walls.

o This enabled the construction team to install windows and curtain walling to form an effective watertight seal allowing the first fix to commence at an earlier date than would have previously been expected.

o Routing of services are of utmost importance early in the design process, mistakes can be time consuming to rectify.

Windows inserted forming building envelope, installation of insulation and brickwork (Images: Robert Greshoff)

Lightweight horizontal formwork system removed and cantilever propped (Image: Luciano Vitello)

Left, remedial work needed to re-route services (Images: Darren Higgins)

Detail 1 – Cantilevered Soffito Horizontal formwork system erected

o Reinforcing positionedo Concrete slab pouredo Vertical formwork system is erectedo Reinforcing positionedo Concrete pouredo Vertical formwork strucko Horizontal system remains in positiono Horizontal formwork struck o Slab propped until fully curedo Props removed.o Acoustic resilient layer lapped and tappedo Floor and perimeter insulation laido Screen pouredo Skirting and internal floor finish insertedo Masonry support system wall ties fixedo Brick laid, cavity tray positionedo Insulation cut and secured in placeo Fire barrier inserted and DPC lapped overo Insulation and brickwork continue verticallyo Soffit support system to underside of slabo Brickslip system fixedo MVHR system installedo Remaining soffit supports installedo Timber soffit finish with insect mesh fitted

Detail 2 – External Wall/Soffito Vertical formwork system erected

o Reinforcing positionedo Concrete pouredo Horizontal formwork system is erectedo Reinforcing positionedo Concrete pouredo Vertical formwork strucko Horizontal system remains in positiono Horizontal formwork struck o Slab propped until fully curedo Props removedo Wall ties fixed o External insulation cut and secured o Brickwork laido MVHR system installedo First fix startedo Acoustic resilient layer lapped and tappedo Floor insulation laido Screed poured, internal floor finish fittedo Soffit support system to underside of slabo Shadow gap feature fixedo Insulation to soffit and envelope appliedo DPC lapped and sealed o Remaining soffit supports installedo Timber soffit finish with insect mesh fitted

Detail 3 – Window Sectiono Vertical formwork system erected

o Openings for windows inserted o Reinforcing positionedo Concrete pouredo Horizontal formwork system is erectedo Reinforcing positionedo Concrete pouredo Vertical formwork moved to next levelo Horizontal formwork struck o Slab propped until fully curedo Props removedo Timber packers cut to suit and fixedo Windows lifted into positiono Window brackets secured to timber packerso EPDM sealed to face of concrete and lapped

with windows waterproof membraneo Internal finished to bottom floor completeo Acoustic resilient layer lapped and tappedo Perimeter insulation fixed, screed pouredo Toe board fitted, internal floor finish laido Masonry support system securedo External insulation cut and fixed around DPCo Masonry course continued verticallyo External MVHR system installedo Cavity tray placedo DPC lapped and sealed over fire barriero Aluminium flashings by window manufacturer

applied and fully sealed

The End