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Denumire: Petronas TowersLocatie: Kuala Lumpur, Malaysia, 1997Dimensiuni: Inaltime: 451.9m Etaje:88218 000 m2Beton folosit: 160,000 m3Otel folosit: 36,910 tone

Beton monolit de inalta rezistenta pentru fundatie, perimetrul pilastrelor si structura de legatura ofera o capacitate verticala portanta economica, rezistenta solida la incarcatura laterala si o amortizare incredibila pentru confortul ocupantilor. Grinzile de otel ofera punti perpendiculare, economice, eficiente si de camp lung, care sunt usor de adaptat la ulterioare modificari in viitor, le consolideaza un suport cu dimensiuni intre 8,2 si 9.8m lungime Planul turnului are mai multe puncte de legatura si arcuri in consolo, are 16 coloane principale, stabilizatori Vierendeel la jumatatea inaltimii si coloane inclinate pentru contralovituri Un pod unic, sustinut de un arc, se intinde pe o dimentiuse de 58,4m la nivelele 41 si 42, unde turnurile se misca mai mult de 300mm in orice directie. Un varf de otel inoxidabil se afla in varful fiecarui turn Turnurile nu au necesitat nicio amortizare ulterioara Fiecare dintre cele 4 picioare arcuite au cate 3 amortizoare de masa pentru cele 3 moduri principale de comanda vortex Fiecare turn are o greutate de 300,000 de tona metrica europeana (unitatedemas: 1MT= 1 000kg), exercitand o presiune de 1,140 kilopascals

Twin 451.9m (1482 ft) tall towers just completed in Kuala Lumpur, Malaysia, presented a variety of design challenges related to tall buildings and slender members under wind load, and to construction methods in the Far East. Cast-in-place high-strength concrete for the core, perimeter columns and ring beams provides economical vertical load-carrying ability, stiff lateral load resistance, and inherent damping for occupant comfort. Steel beams on metal deck slabs provide eficient, economical and quickly-erected long-span oors which are easily adaptable to future changes in openings and loadings. The unusual tower plan has alternating cantilevered points and arcs, only 16 main tower columns, haunched wind frame ring beams 8.2 to 9.8m (27 to 32 ft) long.Vierendeel outriggers at mid-height and sloped columns at setbacks. A unique arch-supported skybridge spans 58.4 (190 ft) between towers at levels 41 and 42, where the towers move more than 300mm (1 ft) in any direction. A stainless steel pinnacle tops each tower. Extensive analytical, force balance and aeroelastic wind tudies addressed individual tower behavior, influences between towers, pinnacle behavior, skybridge overall behavior and arch leg behavior. No supplementary damping was needed for the towers. Pinnacles have simple chain impact dampers. Each of the four arch legs has three tuned mass dampers for the three main modes ofvortex excitation.A fost folosit ciment, care a adus numeroase beneficii: Pe plan economic. Pentru coloane, cimentul de inalta rezistenta reduce spatiul folosit De localizare.Ofera flexibilitate in metodele de constructie si maximizeaza utilizarea de cunostinte a fortei laborale Conexiuni de constructii simplificate. Geometria complexa a coloaenlor, conexiunilor sunt manevrate de niste armaturi metalite Functionabilitate. Un beton principal ofera arbori rezistenti la foc dar si suport structural Eficienta in rigiditatea structurala laterala. Nu este necesara o intarire in sus datorita proportiilor pe care le au membrele inerente ale sistemuli central, care ofera o rigiditate laterala mare Confort in timpul sarcinilorlaterale. Betonul creste densitatea medie de masa, prelungeste perioada de constructii, reduce perceptia miscarii si imbunatateste comfortul lucratorilor in conditii de vant

A fost folosit otel pentru ca a oferit urmatoarele avantaje: Executie rapida. Formele mobile erau nepotrivite pentru planul etajului si ar fi intarziat procesul Fleibilitate in executie. Grinzile metalice nu sunt legate de ciclul de formare a betonului, se poate folosi simultan pe mai multe etaje Fabricare simpla. Grinzile au fost fabricate de producatori locali, astfel au evitat taxele de import Executie simpla. Minimizeaza folosirea macaralelor datorita greutatii mici pe care au au majoratitatea componentelor din otel Devieri previzibile. Perimetrul consta intr-o serie de triunghiuri in consola si cercuri. ignifugare minimizat. Spre deosebire de puntile de metal din SUA, a fost folosit un profil cu nervuri coada de randunica pentru a oferi podele cu greutate normala a betonului de 110 mm timp de 1,5 ore i 125 mm pentru 2 ore, neutilizand spray de foc.Fundatia Turnurile stau pe sol rigid rezidual Kenny Hill, cu substrat calcaros haotic erodat Distanta de la roca de baza variaza dramatic in fiecare turn de la 75 la peste 180m Au fost folosite coeficiente de frecare pentru a distribui incarcatura uniform S-au folosit agrafele de beton (segmente de perete turnat, folosind tehnici de suspensie-perete), de pn la 105 m lungime Agrafele sunt mai lungi n zonele in care roca de baz este mai profund, pentru a uniformiza aezrile. Agrafa de beton a fost setata la 45 MPa (6500 psi cub) putere. Antenele turnurilor au o adancime de 4,5m. The towers sit on stiff Kenny Hill residual soil, with erratically eroded limestone bedrock beneath.Since distance to bedrock varies dramatically across each towerfrom 75 to over 180 m (250 to600 ft) downfriction elements were used to distribute load gradually in the Kenny Hill. See Figure2. Concrete barrettes (wall segments cast using slurry-wall techniques) up to 105 m (344 ft) longwere used, with friction determined by full-scale load tests and improved by skin grouting (pumpingcement grout at high pressure out of ports set along the barrette faces). Barrettes are longer wherebedrock is deeper, to even out settlements. Barrette concrete was specied at 45 Mpa (6500 p.s.i.cube) strength.The tower pile caps/mats are 4.5 m (14.75 ft) deep. The 13 200 m3 (17 250 cu yd) of 60 Mpa(8700 p.s.i. cube) concrete in each mat was cast in one continuous 44 to 50 h operation. To minimizedifferential temperatures, chilled water was used and, ironically, the mat was insulated for a month

Centrul/miezul/nucleul/scheletul este intarit si eficient din cauza a doi pereti solizi de functionare Nord/Sud si unul Est/vest. De aceea intr-un moment de rasturnare, fundatia suporta mai mult din jumatatea impactului Are o dimensiune care variaza de la 23m patrati la 19x22m pe 4 nivele, cu pereti exteriori care au intre 350 simm si 750mm si pereti interiori cu o dimensiune constanta de 350mm, care impiedica aparitia complicatiior in cazul burlanelor de aerisire Peste nivelul 70, colturile sunt spre interior pentru a nu ingreuna rotatia biroului Calitatea betonului variaza in 3 nivele, de la 80 la 40Mpa, corespunzatoare cu cea a coloanei turnului Cadrul(frame) are 307 parti Lungime: 41m

For the PETRONAS Twin Towers, two virtually solid walls running NorthSouth, and one running EastWest, provide `Webs', for the core `cantilever beam', making the core quite stiff and efficient. As a result, it carries slightly more than half the wind overturning moment at the foundation. To resist wind the core has thick, heavily reinforced corners (see Figure 4). The overall core varies from about 23 m (75 ft) square to 19622 m (62673 ft) in four steps, with outer walls varying from 750 mm (30 in.) to 350 mm (14 in.) and inner walls a constant 350 mm (14 in.) to avoid complications with lift shafts and the self-climbing forming systems. Above level 70, corners of the core drop back to avoid `pinching' office circulation against the perimeter columns.Concrete grade varies in three steps from 80 to 40 Mpa, matching tower column grades

Coloanele Au fost obtinute in forme de otel reutilizabile Cele 16 coloane ale turnurilor au inaltimi diferite, de la un diametru de 2,4m la 1,2m Betonul a variat intre 80Mpa (11 600 p.s.i cub, 10.000 p.s.i cilindru) si 30 Mpa( 5800p.s.i cub, 4900 p.s.i cilindru), pe 3 nivele Dimensiunea diametrelor celor 12 coloane inalta variaza intre 1,4m si 1m S-au folosit forme rotunde pentru coloanele de beton De la etajul 84,pentru ca oblicitatea este mai mare s-au folosit coloane de otel

Columns were cast in reusable steel forms and will be open to view at most oors after chipping ns,filling voids and bug holes, and priming the surface for finish painting. The sixteen tower columns vary along their height from 2.4m (7.9 ft) diameter to 1.2m (3.9 ft).Five size increments minimized the time and cost associated with formwork changes. Concrete variedfrom 80 Mpa (11 600 p.s.i. cube, 10 000 p.s.i. cylinder) to 30 Mpa (5800 p.s.i. cube, 4900 p.s.i. cylinder) in three steps. The twelve bustle columns step in size three times, from 1.4m (4.6 ft) to 1m diameter. Sloping concrete columns use round forms with modified formwork ends. Above floor 84 slopes are greatest and steel columns and ring beams are used to avoid complicated, and therefore slow, concrete formwork construction

Grinda/BEAM

Adancimea lor variaza intre 1,15m la coloane si 727mm la jumatatea turnului sau 775mm in cazul conductei de aer conditionat Aceasta ofera o rigiditate de 34% mai mult decat o grinda uniforma cu aceeasi adancime Calitatea betonului corespunde cu cea a turnurilor pentru a simplifica transportul si pompajul betonului

Perimeter frames at tower and bustle use tapered or haunched ring beams all around. Beam depth varies from 1.15m (3.8 ft) at columns to a at zone 725mm (2.4 ft) deep at tower beam midspan or 775mm (2.5 ft) at bustle midspan to pass ductwork. This works well for stiffness against sidesway, providing 34% more stiffness than a uniform beam of the same average depth. Beam concrete grades match column grades to simplify tracking and concrete pumping.

Console de reazem

Cele din est-vest conecteaza centrul si coloanele perimetrului la etajele 38-40 Vantul are o raza mai mare de actiune aici din cauza formei 3 tipuri de grinzi au fost alipite la pilonii mijlocii pentru a intari rezistenta la vant si pentru a minimiza diferenta de miscorare intre centru si coloane

EastWest outriggers link the core and perimeter columns at levels 3840. Wind in this direction acts on a larger area due to the bustle. Three levels of beams linked by midspan posts were sized to help resist wind overturning while minimizing forces from differential shortening of core and columns.

Podul exterior

Un pod cu doua etaje cu o lungime de 58,4m conecteaza cele doua turnuri la tetajele 41 si 42 La o inaltime de 170m Greutate: 750 tone Datorita inaltimii si deschiderii mari a fost folosit otel profilat pentru a facilita contructia si a reduce greutatea. A fost folosit un arc cu doua articulatii si placii continue ale etajului pentru a minimiza rostul de dilatatie, care porneste de la etajul 29 si se ridica pana la 63 de grade pentru a sustine podul S-a luat in considerare efectul complex de migratie, inclusiv cele ale centrului datorita unei eventuale surpari a turnului, iar unghiul arcului se adapteaza la aceste miscari pentru a mentine echilibrul Picioarele podului au aproximativ 42,6m lungime si cataresc 60 de tone fiecare

Varfurile

Fiecare turn are cate un varf de 73mm proiectate cu lumina pentr aviatie si parafulger Este folosit otel de la un capat la celalalt Varful inferior are 8 cadre de otel in forma de stea,interioare, care stabilizeaza varful superior Varful superior este o singura coloana cu o sectiune transversala de cerc patrat, atasat de la cele 4 fete rotunde ale unei placi de otel fundamentale la 4 colturi inoxidabile

The upper pinnacle is a single mast of tapering `squared circle' cross-section assembled from four faces of curved, structurally functional stainless steel plate bolted to four stainless corner fins

Studii dinamice- turnuri

Proprietatile dinamice sunt importante pentru efectele vantului de travers asupra structurii si comportului pe care il ofera cladirea Fiecare turn a fost modelat tridimensional folosit SAP90 Podul a fost proiectat separate de turnuri pentru a usura constructia

For the overall structural loading, the force-balance and ANSI/ASCE values were very close. Aeroelastic values using 2% of critical damping showed slightly reduced base forces at one tower and slightly increased base forces at the other. Because even a slight increase in damping for `50 year storm' movements would reduce aeroelastic results, the design of both towers was based on the largest force-balance results for either tower.For occupant response, an inherent internal damping of 2% and a `10 year storm' gives peak accelerations at level 87 of 17 to 20 milli-g's from force-balance tests and 14 to 18 milli-g's fromaeroelastic tests well within the commonly used 21 milli-g guideline for comfortable office ccupancy in long-period buildings. Therefore no supplementary damping, such as viscoelastic pads or tuned mass dampers (TMDMs) was needed or provided.

Concluzie

Turnurile folosesc o contructie complexa pentru a obtine beneficii in cost, mod de utilizare sit imp Prezinta numeroase exemple de obiecte ascutite, predispuse la vant Se economiseste spatiu prin folosirea unui beton de inalta rezistenta in centrul, coloaenle perimetrului si in grinzi Contructia de beton foloseste un echipament relative usor si simplu