910_saw_kaeng krachan elephant house at zurich zoo_low_v2

8/10/2019 910_saw_Kaeng Krachan Elephant House at Zurich Zoo_low_V2

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SIKA AT WORK

THE KAENG KRACHAN ELEPHANTHOUSE AT ZURICH ZOOSIKA® SYSTEMS “FROM BASEMENT TO ROOF”



BASEMENT TO ROOF SOLUTIONSFOR ELEPHANT HOUSE ATZURICH ZOO

PROJECT DESCRIPTIONThe Kaeng Krachan Elephant Park in Zurich Zoo is innova-tive in design and also in the way in which the elephants arelooked after. The zoo’s growing elephant family now has morethan six times as much room as they did before, including anumber of different pools and showers both indoors and out-side, which they make active use of. Asian elephants are goodswimmers, as they frequently cross stretches of water in thewild and often bathe in order to regulate their body tempera-ture and look after their skin. Visitors can now also see theelephants when they are swimming from a special underwaterviewpoint.

Another husbandry innovation is that the animals are nowcared for in “protected contact” at all times. This means thatthe keepers are no longer in the same room as the elephants,which gives the animals more freedom to develop theirnormal social structure and behaviour, plus this also ensuresgreater safety for the zoo’s staff.

The centrepiece of the 11,000 m 2 elephant park is the unique6,800 m 2 elephant house, an 80 m diameter facility with amulti-faceted timber roof structure weighing more than 1500tons. This free-form, at roof design requires no additionalcolumns inside for support, plus in addition to weatherproof-ing and insulating the building, it also successfully uses thenatural light provided by a total of 271 different shaped sky-lights to simulate the forest canopy of the elephants' naturalhabitat in Thailand.

This roof is supported by a ne architectural ligree concreteframework around the perimeter, but primarily the loads fromthe huge timber frame and shell are absorbed circumferen-tially by the structural foundations. These consist of a pre-stressed, free running concrete ring beam that transfers theload to the ground at three low points in the facade throughspecially piled foundations. The ring beam runs around thebuilding for a total length of approx. 270 m, its cross-sectionis approximately 48 x 200 cm, however it is not rectangular,but adapted to the curvature of the structure.



PROJECT REQUIREMENTSStructural Foundations, Watertight Basements and Archi-tectural Concrete Facades : – Initially on site the main exca-vation required slope stability, with sprayed concrete sidesand pile walls being necessary prior to the main constructionworks.

For the structural foundations, including the prestressed ringbeam, the highest specications were set for the concretewith regards to strength development, self-compaction, lowshrinkage and optimum installation within dened minimumtime frames. A self-compacting mix and a maximum particlegrading of 16 mm were stipulated due to the reinforcementdensity in the ring beam i.e. shear and torsion bars, withdense ange reinforcement around both axes, plus up to veprestressing 2 cable ducts in the same cross-section. A “lowshrinkage” specication was also demanded for the structuralconcrete and the oor slabs of the building in order to mini-mize deformation and cracking.

The majority of the facilities utility services and plant rooms,together with some of the animal stalls, are built below, orpartially below ground, which required them to be designedand built as watertight structures. This is to prevent anyground water penetration and equally to prevent and con-tamination of the ground water by animal excretions or wastewater from the daily activities and cleaning regimes in thefacility.

The sustainable construction approach for this project also re-quired that rainwater from the roof was collected and storedfor use in the facility; reinforced concrete holding tanks forthis purpose were therefore designed in such a way as to alsofunction as an integral part of the structure and so had beabsolutely watertight.



SIKA AT WORK

THE KAENG KRACHAN ELEPHANT HOUSE AT ZURICH ZOO

Structural Glazing: Elastic, movement accommodating, butairtight, bedding for the glazing was necessary to preventstress and unwanted constraints on the glass panels. TheEngineers therefore checked materials for their suitability bycarrying out compatibility and adhesive tensile strength tests.

Roof Waterproong: – The roof itself is unique, but a wellproven and secure system was essential for the roof wa-terproong, including around the 271 roof lights, each witha different shape. All of the necessary upstands, supportplatforms and approximately 1,500 corner sections had to beconstructed by hand due to the variable angles for which stan-dard proles were not available.

To meet the architect’s aesthetic requirements and also tocreate a safe working level for cleaning and maintenance, acontinuous timber platform was designed to span the roof50 cm above the waterproong membrane; this structure isset on 5,615 supports that also needed to be waterproofedwith the membrane system.

Flooring, Containment Lining & Waterproong: – Mechani-cally and chemically resistant ooring that is also easy toclean and very durable was required in many areas. The animalhusbandry and management area of the elephant house ac-commodates the feeding and holding stalls, together withthe veterinary and medical treatment / operating rooms, plusthe facilities utility service controls and plant rooms. Thesehigh-tech and hygienic areas all demanded a top-quality n-ish for efficient running of the facility and for the good of theelephants.



SIKA AT WORK

THE KAENG KRACHAN ELEPHANT HOUSE AT ZURICH ZOO

SIKA SOLUTIONSStructural Foundations, Watertight Basements and Ar-chitectural Concrete Facades: – All of the concrete for thespecialist structural and watertight performance demandsof the elephant house was produced using Sika ViscoCrete®admixture technology, including the ring beam to accommo-date the roof loads and support the entire main building. Themain excavation also required slope stability, with sprayedconcrete sides and pile walls, once again Sika® ViscoCrete®admixtures were used, here in combination with and Sigunit®sprayed concrete accelerators for optimum performance andrapid completion of the sprayed concrete walls between thepiles. The sprayed concrete was applied by the Sika® Sprintermobile spray machine.

The ne ligree reinforced concrete support structure forthe architectural facades was also made possible using thelatest generation Sika® ViscoCrete® technology, in order toachieve the optimum concrete ow, compaction and ultimatestrengths.

The watertight areas and structures used Sika’s engineeredwaterproong solutions to seal and accommodate the re-quired movement capabilities in all of the joints, including theSikadur®-Combiex® system. Sika® Control technology wasalso used in the concrete to prevent shrinkage cracking in theoor slabs.

SikaGrout® technology was used to x and seal the roof sup-ports into the structure

Structural Glazing: As a result of the Engineers testing ofthe different materials proposed, Sikasil® structural glazingadhesives and sealants were used for structural bonding ofthe overhead glazing in adapted proles, plus sealing and UV-resistant bonding of the insulated glazing for the edge seals.

Roof Waterproong: – The roof was produced and water-proofed with a Sika® Sarnal® roong system, fully bonded tothe Duripanel boards, thus allowing joints in this substructureto be fully and securely bridged.

The base of each platform support was enclosed in a mainte-nance-free Sarnal® T tting that was specially developed forthe project by Sika.

Flooring, Containment Lining & Waterproong: – Fast-cur-ing, sprayed Sikalastic® polyurea technology was selected asthe ideal solution to waterproof and provide highly impact andchemically resistant linings on the exposed concrete surfaces.This system was used throughout the elephant house and forprotection of the water retaining and holding tanks, includ-ing the waste-water containment and treatment facilities.Sikaoor® resin systems were applied on all of the traffickedand exposed oors in the visitor entry and access corridors.

SIKA® SYSTEMS FROM"BASEMENT TO ROOF”THE PROJECT PARTICIPANTSOwner: Zoo Zürich AGLead Architects: Markus Schietsch Architekten GmbH, ZurichStructural Engineer: Zoo Zürich AGContractor: Zoo Zürich AG



THE KAENG KRACHAN ELEPHANTHOUSE AT ZURICH ZOO

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SIKA SERVICES AGTueffenwies 16CH-8048 ZurichSwitzerland

ContactPhone +41 58 436 75 78Fax +41 58 436 78 83www.sika.com

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910_saw_kaeng krachan elephant house at zurich zoo_low_v2

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