NUK II,
Narodna in univerzitetna knjižnica Ljubljana (mednarodni natečaj 2012)

Vodilni motiv urbanistično arhitekturne zasnove NUK II izvira iz glavne kulturno zgodovinske vrednote ostankov Emone ohranjene na gradbeni parceli. To je dobro ohranjeno križišče dveh rimskih ulic, ki ga definirajo štiri insule. Preplet urbanističnega rastra rimske Emone in današnjih gradbenih linij v strukturi stavbnih mas nove knjižnice posledično izpostavi prisotnost rimskih izkopanin v tem območju in po drugi strani omogoči organsko umestitev novega stavbnega volumna v obstoječi prostorski kontekst ter izoblikovanje zanimivih notranjih prostorov.

Tloris štirih, na zunanji strani po današnjih gradbenih linijah odrezanih Emonskih insul, je ekstrudiran do višine 24m in tvori osnovni stavbni volumen. V sredino tako dobljenih stavbnih mas sta vloženi dve nadstropji knjižnih skladišč, ki vse štiri volumne povežejo med seboj, obenem pa po horizontali prerežejo odprti prostor nekdanjih rimskih ulic ter ustvarijo dva osrednja več etažna notranja prostora: v spodnjem delu glavno avlo in v zgornjem delu glavno čitalnico. Vogalni volumen, med obema glavnima vhodoma z Rimske in Zoisove ceste v osi rimskih cest, je spodaj odrezan in odpira notranjost knjižnice ter izpostavlja izkopanine pod njo. Večji stavbni volumen ob Emonski cesti je na poziciji nekdanjega notranjega atrija izvotljen tako, da nastane zgoraj dve višinski del knjižnice, spodaj pa dve višinski prostor kavarne.

Stavba je kompaktna celota, ki zapolnjuje praktično ves razpoložljivi prostor. S cestne strani je stavba pravilno oblikovan volumen z ravnim zaključnim vencem, ki poudarja njeno pomembnost. Po višini sledi obstoječim izobraževalnim objektom ob mestnem ringu. Višinski preskok proti Križankam opredeljuje mejo nekdanje Emone na eni strani in srednjeveškega mesta na drugi strani. Nova kompaktna zazidava zaključi stavbni blok modernega mesta. Nižja starejša zazidava ob Rimski cesti se ohrani kot zanimiva zgodovinska značilnost te ceste. Na severnem koncu je nakazana možnost kasnejše širitve knjižnice in lokacija četrtega vertikalnega jedra.

Izbrana je relativno umirjena fasadna kompozicija, nevtralen kolorit ter za obravnavani prostor običajni materiali kot so steklo in umetni kamen. Tako se nova stavba nevsiljivo vključi v občutljiv historični prostor ter izraža potrebno resnost, dostojanstvo in reprezentančni značaj. Premišljena kompozicija praznin, prepletenih z zelenjem, kljub temu naredi stavbo moderno in dinamično ter vnaša v javni prostor zanimivo napetost in identiteto.

Simbolna govorica fasadne kompozicije, določena z belo mrežo senčil, nakazuje urejeno zbiranje znanja, ki se skozi čas, v vedno novih plasteh, nalaga v stavbi. Horizontalni pasovi z neenakomernim ritmom vertikal so odraz raznolikosti virov in vmesnih praznin ter digitalne dobe (črtna koda) v kateri knjižnica nastaja. Bela barva pomeni čistost in resnico ter neskončno število še nepopisanih listov, ki čakajo na prihodnja spoznanja. Pred velikima razglednima oknoma nad obema vhodoma je zasajena trta, ki zmehča pogled na stavbo in iz nje ter nas opozarja na prepletenost dela človeških rok z naravo. Spomni na slovensko nacionalno himno in v tej povezavi deluje kot slovenski nacionalni simbol.

Glavna avla, dvovišinski prostor na poziciji rimskih ulic, je poljavni vstopni prostor in osrednje mesto celotnega programa knjižnice. S svojo razsežnostjo nadomešča nekoliko skromneje odmerjeni prostor pred knjižnico. Okoli nje so nanizani vsi vzporedni programi NUK II, od recepcije in osrednjega informacijskega pulta z otokom digitalne knjižnice preko 24h čitalnice in kluba, do avditorija, trgovinice, večje kavarne ter garderob s sanitarijami. Tu je urejenih tudi več predstavitvenih točk nekdanje Emone. V obsežnem prostoru glavne avle, namenjenemu številnim neformalnim stikom, se bodo zvrstile različne občasne razstave in drugi dogodki. Vsi programi v spodnjem delu so dostopni iz glavne avle in so lahko odprti tudi izven delovnega časa knjižnice, kjer je vstop posebej kontroliran.

Predelne stene v tem delu so izvedene kot steklene muzejske vitrine, postavljene v linijah ohranjenih rimskih zidov; v spodnjem delu kažejo ostanke zidov, nad višino 70cm pa so stekla vitrin prekrita s potiskom kovinske barve z izrezi za predstavitev najdenih predmetov, v zgornjem delu pa s perforacijo, ki kot čipka zastira programe v medetaži. Dvovišinski prostor s stropom, osvetljenim z računalniško vodeno LED tehnologijo, ki simulira odprto nebo, daje obiskovalcu pravo tridimenzionalno doživetje velikosti rimskih cest in križišča.

Glavna čitalnica, tri višinski prostor s stekleno shed streho, nad tlorisom obeh rimskih ulic, je osrednji prostor odprte knjižnice. Obdelana je v svetlem lesu. Okoli nje so v treh etažah nanizani vsi knjižnični programi ter med seboj povezani s stopnišči in pasarelami. Časniki v prostem pristopu so locirani v medetaži spodnjega javnega dela s katerim ohranjajo vizualni stik. Velika panoramska okna se na koncu vzhodnega trakta odpirajo proti Križankam in Gradu, na koncu južnega trakta pa proti Krimu.

Komunikacije za obiskovalce so, v nasprotju s trgovskim centrom, kjer se mora obiskovalec izgubiti med trgovinami, jasne in pregledne. V spodnjem delu daje orientacijo glavna avla, zgoraj pa glavna čitalnica. Povezani sta s skupino treh panoramskih dvigal, postavljenih za kontrolno linijo v pritličju in dobro vidnih iz obeh osrednjih prostorov. Za zaposlene so predvidena tri vertikalna jedra s stopniščem, dvigalom in instalacijskim jaškom, ki so sistemsko in pravilno razvrščena. Ob njih so po etažah manjše sanitarije in čajne kuhinje. Četrto, za primer kasnejše širitve, je nakazano na simetrični poziciji. Služijo za komunikacijo uslužbencev in kot požarna stopnišča. Severno jedro služi kot glavni dostop za osebje in za prihajajoče ter odhajajoče knjige iz nabave in medknjižnične izposoje, medtem ko zahodno jedro, okoli katerega so locirane vse informacijske točke, služi za zbiranje vrnjenih knjig s strani obiskovalcev.

Objekt bo izpolnjeval zahteve za energetski razred »A« in bo energetsko pozitiven. Kot vir energije za ogrevanje, hlajenje in sanitarno toplo vodo so predvidene visoko učinkovite reverzibilne toplotne črpalke voda-voda z uporabo podtalnice. Prezračevalno klimatske naprave bodo zagotavljale več kot 75% rekuperacijo toplote. Stavba je zasnovana tako, da maksimalno izkorišča naravno dnevno svetlobo. Umetna razsvetljava je izvedena z varčnimi LED svetili. V stekleno shed streho čitalnice so vkomponirani PV paneli za pridobivanje sončne električne energije.

Fasadni ovoj je tehnološko sodobno zasnovan. Pred zastekljeni toplotni ovoj, ki spušča v notranjost stavbe kar največ dnevne svetlobe, je obešena mreža senčil, ki v vročih dneh ščiti pred direktnimi sončnimi žarki, za nizko zimsko sonce pa so na notranji strani senzorsko vodeni beli prosojni screen-i.

The leading motif of the new library design stems from the most important historical element of the former Roman city Emona, preserved on the building site. That is a well preserved crossing of two Roman streets, defined by four building blocks (insulae). The volumetric structure of the new library reflects the superposition of Roman Emona urban grid and contemporary building lines, which consequently exposes the presence of Roman ruins in this area. On the other hand, this enables an organic implantation of the new structure into the existing urban fabric and creation of interesting internal spaces.

The floor plan of the four Roman insulae, on the external side arbitrarily cut by the building lines of contemporary city streets, has been extruded to the height of 24m to define the basic building volume. Then, two floors of compact book storage have been inserted in the middle of it, to connect four separate volumes in a whole and to form two central double-height spaces above the Roman streets: aula magna below and the main reading room above. The lower part of the corner volume, between the two main entrances from Emonska and Zoisova Roads in the axis of Roman streets, has been cut out to open the library interior and expose the Roman ruins underneath. The larger building volume at Emonska Road has been also hollowed out on the position of a Roman atrium, so that a double height space has been formed above in the open library and below in the restaurant.

The library building is a compact whole, filling almost all available space. From the street side it is a regular volume with a straight horizontal cornice, emphasizing its importance. Its height follows the height of existing educational buildings along the city ring. The radical drop of height at Križanke area marks the border of Emona on one side and medieval Ljubljana on the other. The new compact construction completes the building block of the modern city. The lower older buildings on Rimska Road are preserved as an interesting historical characteristic of this street. The possibility for later library extension is indicated on the northern side, where the position of the possible fourth communications core is shown.

A calm formal expression of the exterior, a neutral color scheme and common local materials, such as glass and artificial stone are selected. In this way, the new building is smoothly implanted into the historically sensitive space and expresses the necessary seriousness, dignity and representativeness. A thoughtful composition of voids, interwoven with greenery, makes the new library modern and dynamic and brings into the public space an interesting tension and identity.

The symbolic language of the façade, defined by a white net of sunshades, indicates an organized and never ending collection of knowledge, which is piling up in the library in always new layers. Horizontal strips with an irregular rhythm of verticals reflect the diversity of sources and voids in-between, as well as the digital era (bar code) in which the library is being built. The white color means purity and truth as well as an endless number of yet blank pages waiting for future knowledge. In front of large panoramic windows above the two entrances a vine is planted to humanize the view of and from the building and to remind us how the man-made world and nature are interwoven. It also reminds us of the Slovenian national anthem and acts as a Slovenian national symbol.

Aula magna, a double-height space on the position of Roman streets, is a semi-public entrance area and the focus of all activities in the building. Its size replaces rather small public area in front of the library. Here, one can find the reception and the main library information desk, 24-hour reading room and the library club, auditorium, library shop, restaurant, wardrobes and toilets. Here, one will discover many permanent presentation points of Emona and in its vast space of countless informal social contacts, temporary exhibitions and other events will take place. All activities in this part of the building are accessible irrespective of the working hours of the library, since its entrance is additionally controlled.

Partition walls in this area are designed as glass museum showcases, placed over the preserved Roman walls: below they show the remnants of Roman walls, while above 70cm they are covered by metal color print with cutouts for presentation of excavated items and on top perforated to screen the working rooms in mezzanine. The double height-space with a computer driven LED illuminated ceiling, imitating open sky, gives the visitor a real three dimensional experience of the size of roman streets and crossing.

The main reading room, a triple-height space with a shed glass roof, above the contours of Roman streets, is the central space of the open library. It is clad in light natural wood. All library programs are placed around it in three levels and are connected by stairs and walkways. Reading room for newspapers is located in the mezzanine of the lower part, with which it is visually connected. Two large panoramic windows open towards Križanke and the Ljubljana Castle on the east and towards Krim Mountain on the south.

Communications for visitors are clear and transparent, in contrast with modern shopping centers, where one is supposed to get lost between shops. Easy orientation for visitors below is provided by aula magna and by the main reading room above. They are connected by a group of three panoramic elevators, located behind the control line on the ground floor, well visible from both central spaces. For employees, three vertical cores with staircase, elevator and installation shaft are located in a regular disposition. Lavatories and kitchenettes are located beside them on each floor. The fourth core is indicated on a symmetrical position, in case of later expansion of the library. They are used as communication for employees and as fire escapes. The northern core is used as the main access for the staff and for incoming and outgoing books, acquired a new or from dislocated storages or lent to other libraries, while the one on the west side, where all information desks ale located, serves for collection of returned books from visitors.

The building fulfills the requirements for the highest class A regarding an efficient use of energy an will be energy positive. Effective reversible heat pumps water-water are used as source of energy for heating, cooling and hot sanitary water, using shallow groundwater. Ventilation system recuperates more than 75% of heat from the waste air. The building is designed in such a way to use the maximum amount of natural daylight. For artificial illumination LED technology is used. PV panels are incorporated in the glass shed roof to produce solar electricity.

The façade envelope is designed on the basis of latest technologies. In front of the glass thermal envelope, letting into the building as much natural light as possible, a mesh of sunshades is attached to protect the interior against direct sun exposure in hot days, while the low winter sun is shaded by sensor regulated translucent white screens on the inner side.