Spider Truss Pipe

7/27/2019 Spider Truss Pipe

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MODERN STEEL CONSTRUCTION january 2010

hospitality

PCLConstructors

By Doug CaPLan

Spkliasym

metry


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january 2010 MODERN STEEL CONSTRUCTION

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A larger-than-life diamond relies on carefully detailed structural steel.

LOCaTED 12 MILES fROM VERNON, BRITISh COLUMBIa,

approximately halway between Calgary, Alberta, and Vancouver,British Columbia, the new Sparkling Hill Resort is scheduled to

open in March 2010. Perched atop a spectacular granite ridge thisstunning our-story, 152-room hotel overlooks the Okanagan Val-ley to the north and Okanagan Lake to the south.

Promising to be no less dazzling than the surrounding country-side, the resort eatures the best that can be ound in comort andrejuvenation: spa, yoga, massage, and more, as the rst true Euro-pean-style wellness hotel in North America.

In that spirit, a glass-encased crystal atrium, a compelling sym-bol or Sparkling Hill Resort, welcomes guests as the main architec-tural eature at its ront entrance. The atriums glass arrangement

was inspired by a Swarovski Crystal and is built on a structuralsteel rame. It is a non-symmetrical assembly o 15 large glass tri-angles, all having dierent dimensions and sloping in many dier-ent directions and planes. The crystal structure spans 13 m wideand stands 17 m above the second foor. Its top edge is more thanour stories high.

The crystal is visible rom a great distance. Air travelers as ar as20 km away will recognize the suns refections emanating rom thecrystal, and those on the ground will marvel at the crystals refec-tions and reractions as they drive by.

Building te Jewel o te Okngn

As the main architectural eature o the Sparkling Hill Resort,this avant-garde structure pushed the boundaries o possibilities.

The architects and engineers decided upon a large structural

steel pipe rame or supporting the glass panels orming the crys-tal structure. The crystal rame is made rom 8-in. standard pipepositioned 100 mm (slightly less than 4 in.) behind the glass panels,inside the building. The pipes ollow all the joining triangular glasspanel seams. Brackets attached to the pipe support the glass panels.

The triangles or this crystal are arranged to create three apexes,that is, three dierent points where the corner o either six or eighttriangles would converge. That meant all o the pipes behind thetriangular glass panels needed to converge at common work points.

This conguration resulted in every pipe having a dierent trajec-tory relative to the other pipes. No two panels were even remotelysimilar, which promised to make the steel abrication both inter-esting and challenging.

Because o the sites mountain-top location, the schedule wasvery tight. The crystal needed to be completed beore winterarrived. The design o the steel pipe rame, however, was still a

work in progress when the project went out or tender. The gen-eral contractor, PCL Constructors, knew that the lowest bidderwould not be the deciding actor in awarding this type o work.The rst priority was nding trades with a reputation or qualityworkmanship. For the crystal structure, in particular, there were nosecond chances. It had to be done right the rst time. The general

Doug Caplan is the owner ofDECCON Steel DetailingServices, Ltd., Surrey, BritishColumbia (www.decsteel.com).He was the companys projectmanager for the Sparkling Hill

Resort project.

Opposite pge: a steel pipe fmewk sppts the f-st lss

cstl t the htel etce, setti te f elece f visits tthe Spkli Hill rest i Ve, Bitish Clmbi.

Rendering nd poto, bove: at sme pits s m eiht lsspels cme tethe st iches bve the steel fmewk, mkipecisi detili d fbicti impetive.

edei & pht: DECCon Steel Detili


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MODERN STEEL CONSTRUCTION january 2010

contractor chose a steel abricator and steel detailer based on theirexperience and past history o success, collaboration and integrity.

The architect provided two sets o 3D coordinates, whichconsisted o 21 individual coordinates or the pipe rame and 14individual coordinates dening the corners o the triangular glasspanels. The 3D model was constructed using these two sets ocoordinates. The datum or all coordinates was to originate roma common point or the entire project so that all trades would be

working to and rom the same point.The glass panels are held in place by a pre-tensioned wire cable

system. A total o 150 cables are required to secure 27 glass struts,which are perpendicular to the glass panels. One end o the strut isattached to the glass. The other end, standing 500 mm below theglass, is held and locked in place by our 10-mm-diameter stainlesssteel cables. Struts and cables were supplied by the glass supplier.

The abricator, however, became responsible or supplying andinstalling more than 170 connector plates on the steel pipe rame

or the cables. The detailer was responsible or the steel detail-ing o the entire project and or locating all the cable connectorplates on the steel pipe rame. Because the cables needed to be pre-tensioned and ordered beore the crystal was erected, the detailerprovided the glass supplier 3D models so that they could measureaccurately the length o the cables.

Each cable has a clevis on the end that attaches to the con-nector plate on the pipe rame. Erection clearances were so tight

afte the fme hd bee pied d its emet dsted, the c-ectis wee welded. The cews istlled the ttchmet hdwetht wld hld the lss pels. Pht ctes f W Steel-Tech, Kelw, Bitish Clmbi, Cd.

WaraarSteel-Tech.


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january 2010 MODERN STEEL CONSTRUCTION

that each workpoint needed to be incre-mentally moved away rom the intended

workpoint to ensure adequate erectionclearance or the cable clevis pin. As each

workpoint was re-located, the adjacentworkpoint also needed to be re-alignedto satisy the geometry that engineers hadmeticulously worked out. This was oneo the most time consuming and complex

tasks that the detailer had to deal with, orboth the 3D modelling o the structure as

well as the 2D shop drawings. The pipejunctions just below the glass apex have asmany as eight pipes coming to a common

workpoint, which required modeling in 16cable connector plates to a hub or a totalo 24 entities all coming in rom dierentangles, at dierent slopes, to converge atthe same vertex.

To nd an acceptable location or all thecable connector plates, the detailer addedto its 3D model all o the glass panels,

the 27 glass support struts and stabilizingcables, and cable clevises. This was essen-tial or nding and eliminating any clashbetween cable clevis and pipe, betweencable and pipe, clevis and gusset plates, etc.It also was critical or veriying boltingclearances or the clevis pins and weldingaccess or the cable connector plates. Everycable connector plate had to be re-enteredinto the model several times until a suitablelocation was ound by trial and error. Eachre-entry shited the connector plate slightlyarther away rom the originally intended

work point until all clearance criteria weremet. This trial and error method was by arthe astest way to nding acceptable loca-tion or connector plates.

fbriction nd Erection

Fabrication began beore the crystalmodel was completed. Due to a very tightconstruction deadline, shop drawings wereintentionally shop issued twice. The maincrystal pipe rame was modelled rst. Shopdrawings were then created while the cable

connector plates were still being enteredinto the model. Once the cable plates wereadded to the model, the 2D shop drawings

were updated.The erection strategy was also planned

very careully. There was a very narrow tol-erance or error in installation o the piperame. The entire crystal structure needed tobe within a ew millimeters o the theoretical3D coordinates established by the architect.The pre-tensioning o the cables allowed ora maximum error o only 10 mm.

The strategy was to erect the entire

rame loosely with erection tabs/bolts that

DECConSteelDetailig

had been placed in the model. Once ullyerected but not ully welded, the entirestructure was aligned with guy wires. Withthe help o a surveyor, all 21 coordinates

were pinned into the correct position.Once pinned securely into position, theentire crystal was ully welded. Duringthe nal welding, coordinates periodically

were rechecked to ensure that nothing hadmoved. The crystal structure was erectedrapidly and eciently, making the nalnode adjustments minimal.

A vital key to the abricators successwas the close collaboration they receivedrom the PCL survey team at the job site.Richard Callihan, senior surveyor or PCLConstructors, uses an advanced survey sys-tem combining a Nikon DTM-352 totalstation and MicroSurvey sotware. Thatsetup allows the surveyor team to solve

complex survey calculations and transerthe inormation directly into the total sta-tion or use in the eld.

Callihan initially placed his instrument45 m rom the crystal pipe rame to assistthe erection crew in placing the rames

workpoint nodes. He could locate anygiven workpoint on the outside surace othe pipe rame, but not the pipe centerlines.However the node coordinates supplied bythe architect were along the centerlines othe pipes. To nd the workpoints along thecenterlines o the pipe rames and help in

moving all 21 nodes on the pipe rame to

their exact coordinates, Callihan and hisassistant came up with a clever idea: usingtwo total stations located 19 m rom oneanother and leveraging their powerul sur-

vey sotware.The erection o the crystal structure

was smooth and error ree. Both the steeldetailing and the steel abrication o thecrystal were done successully and the greatcare taken to do both labor-intensive jobsright paid o.

Owner

Spkli Hill rest, Ve, BitishClmbi, Cd

arcitect

C Desi, Vcve, BitishClmbi, Cd

Engineer

red jes Chistffese CsltiEiees, Victi, Bitish Clmbi,Cd

Generl Contrctor

PCL Cstcts, Kelw, BitishClmbi, Cd

Steel Detiler

DECCon Steel Detili Sevices,Se, Bitish Clmbi, Cd (aISCMembe)

Sotwre

Betle PSteel

oveli ptis f the DECCon 3Dmdel tp f phts fm the shppved t be effective w t cfimtht cmplicted pts wee cectl fbi-

cted. I this pht, the mki the pipe(a3012) shws thh the tslcet eemdel piece. The piece mks the fis lse the steel d shw thh the bwmdel fis.

Spider Truss Pipe

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