Techrete (UK) Ltd. Techrete Ireland Ltd.Techrete (UK) Ltd.

General Enquiries: estimating@techrete.com

www.techrete.com

Sales and Design Office

Feldspar CloseWarren Park WayEnderbyLeicester LE19 4SDEnglandTel: +44 (0)1 162 865 965Fax: +44 (0)1 162 750 778

Design & Production Office

Stephenstown Industrial ParkBalbrigganCo. DublinIreland Tel: +353 (0)1 690 1700Fax: +353 (0)1 690 1777

Production Office

Station RoadScawbyBrigg North LincsDN20 9DTEnglandTel: +44 (0)1 652 659 454Fax: +44 (0)1 652 659 458

A new leading development for John Lewis, set in the heartof Leeds Victoria Quarter opened its doors on the 20thOctober 2016.

Victoria Gate is an outstanding structure bothinternally and externally. It is home to the John Lewisflagship store and internal shopping arcades. The arcadedesign allows light to flood in from above and reflectsLeeds historic shopping arcades.

Externally, the intricate grid façade draws on Leeds richtextile legacy for inspiration and the colour of the Techretereconstituted concrete cladding compliments thesurrounding buildings.

The Techrete team are proud to have been part of thedesign, manufacture and installation of this project to pushthe limits of precast concrete engineering and to help provethat visions can become a reality.

ARCHITECTS: ACME, Friedrich LudewigDEVELOPER: Hammerson PLCMAIN CONTRACTOR: Sir Robert McAlpine3D BIM MODELING: TechretePRECAST CONTRACTOR: Techrete

C O N T E N T S

Introduction

04OVERVIEW Victoria Estate Shopping District06CLADDING DESIGNDesigned to merge with different finishesand conceal joint pattern

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MANUFACTURINGClever Solutions for Manufacturing

12 BIM 3D MODEL Quality and Accuracy 16

LOGISTICS & INSTALLATIONDeploying Skilled Resources20

ABOUT VICTORIA GATEFlagship John Lewis Store

VICTORIA GATE

V I C T O R I A G AT E

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VICTORIA GATE, LEEDS

Victoria Gate is a flagship John Lewis store with a strikingfaçade and a 21st century elegant arcade which echoes Leedsrich arcade history. It is an iconic building with incredibleattention to detail taking architectural inspiration from the Grade IIlisted Victoria Quarter built in the late 19th century and drawingupon the rich history of the textile industry of the area. The newbuilding is wrapped in a grid of diamonds evoking an ultra-lightgeodesic structure, impossible to achieve without the new precastconcrete technologies and the ability of the BIM 3D digital era.

L E E D S0504

OVERVIEW

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Set to transform the city’s retail, dining and leisure appeal, Victoria Gate has become part ofthe new 53,400m2 (575,000 sq ft) Victoria Estate shopping district. This stunningdevelopment was completed in October 2016.

STEEL STRUCTUREAt the perimeter, the structural columns are set out according to adiamond or diagrid geometry, to form a series of raking steelworkcolumns. The horizontal setting out of the nodal intersectionsbetween the centreline of the raking columns is consistent at4200mm and varies perpendicularly with vertical spacing betweennodal intersects getting closer towards the top of the building tosuit the smaller diamond shaped cladding panels at high level.

SUPERSTRUCTUREThe substructure and superstructure of the JLP store wasdesigned in accordance with the landlord’s specification ofworks which set out the parameters of the structural design. TheRC frame building is 5 storeys in height comprising of 4 levels ofretail and a roof level with split plant and restaurant areas.

The structural grid is typically based on 9.6m x 9.6m bayswith four larger 10.8m x 9.6m bays within the central portion ofthe building.

The floor plate cantilevers from interior column positions toform the central atrium void and comprises a 550mm depth RCflat slab within the four larger structural bays.

RC columns are typically 600mm x 600mm within largersales areas and non-sales areas at B1 and B2 levels, with 650mmx 650mm and 700mm x 700mm RC columns to support thelarger column loads.

As well as transmitting axial column loads through the building,the diagrid columns have also been designed to act as part of atruss. At the south east corner of the building, the plant stackfloors are suspended above the delivery entrance with a deep trussfrom first to fourth floors incorporating diagrid columns. Thetruss is designed as a propped cantilever spanning from the firstcolumn position next to the delivery entrance on the southelevation to the tip of the 1400mm deep cantilever beam.

Designed to incorporate different finisheswithin the various sections, the typicalpanel is a composition of variouselements cast separately and combined as a whole inthe final stage of manufacture.

The irregular section varies from 400mm to160mm thick, the N shape configuration to formthe diamond diagrid ranges from approximately6.0m wide and 4.8m high on the lower levels, to4.2m width and 3.1m high to the upper levels.

CLADDING DESIGN

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Typical panel 3D and front view

The diagrid pattern inspired byLeeds textile history needed to bedeconstructed by Techreteengineers to panelise a façade that wouldfit with precast manufacturing needs andpay homage to the richness of theArchitecture.

CLADDING DESIGN

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The design intent of the uniqueconfiguration of the diagrid was toconceal the joint pattern.Early design development with the DesignTeam ensured both architectural intent andstructural requirements could be met toproduce this superb effect.

The complexity of the pleated surfacechallenged engineering and mould makerstoo. When combined with the inclinedjoint pattern, the innovative outcome isevidenced in the finished building.

Single bay configuration

Jointing strategy

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During design development the 3D BIMmodels from all trades were federated.This allows clashes to be identified andremoved early. This process proves to beinvaluable at construction stage saving time andresources.

Innumerable intricate details gleaned from thedesigners’ minds, the geometry, the engineeringand the manufacture were converted into millions

of computer bytes to model a stunning façadewith levels of accuracy never before dreamed of.

In the end, more than 600 drawings starting withgeneral arrangements, followed by bay elevations,sections, plans, steel and concrete builders work,unit drawings, reinforcement and fixing detailshave been generated from the original model tocover the whole process with levels of accuracynever previously envisaged.

CLADDING DESIGN, BIM 3D MODEL

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It would be certainly ambitious to run sucha complex design with a blank paper and apencil. However, the machine to replacehuman creativity has not been yet invented.

As always, the basic principles of the design,developed by our engineers, start with a deepanalysis of the architectural and structuralrequirements, followed by a hand made sketchscheme as the most effective method of

communication. After that, the new 3D BIMtechnology takes over.

Obviously, communications skills areinsufficient without the knowledge of thematerials capacities, new manufacture methodsand the subsequent transport and installationequipment. All of these elements combine tocreate greater efficiencies in the process toensure on-budget delivery of the project.

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CLADDING DESIGN, BIM 3D MODEL

3D model. Back panel view

The precast elements are supported in twolocations through a corbel cast in the panel,transferring the vertical loads to the steelstructure. Due to the complex geometry, the bearingload supports have been located to different levelswithin the same panel. One rests on the horizontalbeam while the other is transferred to the inclinedcolumn.

Finally, four restraint fixings secured to a steel platewelded to the inclined columns give the horizontalstability in the permanent condition.

The panel weight varies according to size.Generally the panels weighed heavier thannormal due to the pleated pattern with theheaviest weighing circa 14 Tonne.

This factor, together with the unusual shape, is not atrivial issue to dismiss when the precast units aredesigned for handling. The lifting fixing locations hadto be carefully positioned according to the panels centreof gravity. This enabled the panel to be rotated whenrequired and lifted into position.

3D model. Front panel view

Victoria Gate, Leeds

The scale and variety of finishes ensuredthat the facilities at both production siteswere utilised on this iconic project. Asmentioned earlier, the concrete panels are madein a two stage cast. The polished prism elementsat the centre of the diagrid were cast in theTechrete factory at Balbriggan (Ireland), whichhouses an automatic polishing machine capableof working 24/7.

Carefully packaged, the polished sections weredispatched via standard transport to thecompany’s facility in Brigg (North Lincolnshire,England), where the final manufacturing stagewas carried out.

Polishing is a delicate process which requiresspecial skills and equipment. The panels are overcast to allow for the external skin to be removedby a grinding stone in the water-cooled process.This procedure removes between 4mm and 6mmfrom the exposed face of the panel.

Once in Brigg, the polished sections arepositioned in the bespoke moulds having takenconsideration of the reduction in the polishthickness to achieve the accuracy level required.After casting, the shiny surface is protected toallow the acid etching of the remaining exposedarea, resulting in a contrast of matt and brightreflections.

To protect and ensure the colour consistency theselected aggregates and sands for the concretemix were carefully stored at both factories in siloswith moisture control.

The manufacturing logistics were somewhat of achallenge. Polished prisms, final panels, specialfixings and other components were specificallyreferenced and tracked along the whole processby the company QA system.

Finally, the resulting products were transportedto the project site where the “in house” erectioncrew proceeded with the panel installation.

MANUFACTURING

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Careful consideration went into solving thegeometry at faceted corners and the challenge tomould manufacturing was immense with no twofacets being the same.

The quality and level of accuracy driven by the 3D BIMmodel has been the key to ensuring the accuracy ofinformation required by the mould manufacturers.

In fact, some of the most difficult moulds were fed directlyfrom the 3D software to the mould makers CNC cuttingmachine to produce a kit of parts and to allow assembly inthe factory works.

The moulds were made in timber, specially reinforced toachieve the required robustness when pouring the concretemix. Once the panel was cast, a hydraulic tilting table wasused to remove it from the mould, repeating the cycle every24 hours.

Thereafter, special care was taken with each unit during thecuring period. The panels were kept indoors during thiscuring process in a controlled environment, which allowedthe monitoring of moisture and temperature.

In the final stage, the polished surfaces were carefullymasked and specialist finishers executed an acid etchingprocess to deliver the texture and tones intended by theArchitect.

2 stage cast and tilting table

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Logistically, the diversity of shapes and weight requiredclever solutions for manufacturing, storage and siteinstallation.Each level came from a different mould family with siteinstallation sequence floor by floor. The faceted units tocorner areas were all unique and installed at the end.

More than 880 cast units cast have been processed throughthe factory logistics system, stored and then loaded ontospecial trailers for delivery to site.

Even though the Brigg factory was not far from theconstruction site, the coordination between the site andfactory teams required top communication skills to ensurethe efficient transportation of panels weighting upto14Tonne on a 60 mile trip.

LOGISTICS & INSTALLATION

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The transport and installation logistics ofsuch highly engineered panels posed somesubstantial challenges.The size of the panels was at the transportationlimits for the national roadways and bridges. Panelswere transported on their side and rotated prior toinstallation to the correct orientation for theirposition on the structure.

The rotation of these panels involved a process ofcareful positioning of the lifting points to ensurethat they were coordinated with the centre ofgravity of the panels. This eliminates the risk of anydamage to the panels during the installation process.

Panels were then lifted off the trailer by the craneand rotated to their correct orientation with theassistance of an air hoist. As evidenced in thephotographs the size, weight, shape and profile ofthese units required ground breaking engineeringinput to ensure a near flawless installation process.

The operation pushed the envelope of thetransportation and logistics element of precastengineering.

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Restrictions placed on the site programrequired additional resources to shortenthe site works time frame.The use of mobile cranes in the early stages ofthe program allowed the installation of thelower level panels to commence prior to thecompletion of the upper levels of thesuperstructure.

Anyone with experience in the manipulation ofheavy loads will appreciate the additionaldifficulty associated with the installation of theunderslung panels at the main entrance.

Retail opening dates, once set, are unmovable.Meeting the target finish date for this stunningbuilding was imperative. Once the structurewas handed over to Techrete, erection crewsworked both day and night shifts to ensure thatset targets were met.

The entire team at Techrete are unbelievablyproud of their achievements on this project andenjoyed working with all the stakeholders tobring this project to fruition.

LOGISTICS & INSTALLATION

West Main Entrance

South West Corner West Elevation

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