When the Willis Tower was conceived in the early 1970s, its architects and engineers faced a challenge no office building had ever encountered at such scale: how to move tens of thousands of people efficiently through more than one hundred floors without turning the structure into a solid block of elevator shafts.
What they created was not merely an elevator system — it was a fully engineered vertical city.
At the time of its completion, the tower contained an astonishing 103 elevators, including 14 double-deck elevators, a highly advanced technology for the era. These double-deck cabs — two elevator cars stacked one on top of the other — allowed twice the number of passengers to move using the same shaft space, dramatically reducing how much of the building had to be sacrificed to vertical circulation.
In total, 97 elevator cabs served office floors, occupying 83 shafts, an extraordinary feat of spatial efficiency for such a massive structure.
But the true innovation was the introduction of the sky lobby system, inspired by urban transit networks.
Rather than sending elevators directly from the ground floor to every office level — which would have required hundreds more shafts — engineers divided the tower into vertical zones.
From the main lobby, passengers could ride express double-deck elevators straight to major transfer hubs located on the 33rd/34th floors and again on the 66th/67th floors. These sky lobbies functioned like vertical subway stations, where people transferred to local elevator banks serving the surrounding floors.
All office floors from the 34th to the 103rd story were reached only through these sky lobbies, making the system both faster and far more space-efficient.
In addition, two high-speed elevators traveled directly from the lobby to the Skydeck on the 103rd floor, carrying millions of visitors to one of the most famous observation decks in the world.
Even logistics were carefully engineered.
The tower included six freight elevators, one of which traveled the full height of the building — over 1,440 feet (440 meters) — serving every single floor. This elevator was also designed for emergency use, reserved for the Chicago Fire Department during fires or evacuations, while other elevators could be remotely controlled from the 33rd floor to assist rescue operations.
Complementing the elevators were 16 escalators, including dramatic double-height escalators connecting the main lobby with lower mezzanine levels, and another set linking the 33rd and 34th floors within the first sky lobby.
At the time of construction, this system was nothing short of revolutionary.
It allowed a megastructure with over 4 million square feet of office space to function smoothly, efficiently, and safely — something previously thought impossible at such heights.
Even today, decades later, the Willis Tower’s elevator design remains a benchmark in skyscraper engineering. Engineers from around the world still study its sky lobby concept, double-deck technology, and traffic flow modeling as foundational principles of modern supertall buildings.
Each year, the elevators carry nearly six million passengers, silently moving an entire working population up and down the tower — just like streets and subways move a city horizontally.
The Willis Tower is not merely tall.
It is a living vertical metropolis — and its elevator system is the infrastructure that makes that city breathe.
Aujourd'hui, j'aimerais écrire sur un bâtiment qui me fascine. Actuellement, il existe déjà de nombreux autres bâtiments aussi hauts que celui-ci, voire plus grands. Par exemple, la tour la plus haute se trouve à Dubaï, suivie du gratte-ciel récemment achevé à
Kuala Lumpur, qui curieusement, dans cette ville il y a quelques années, les célèbres
tours Petronas ont été construites et ce sont elles qui ont arraché le titre de plus haut bâtiment. haut de la
tour willis. Deuxièmement, le troisième bâtiment le plus haut du monde à ce jour est la
tour de Shanghai. puis il y a plusieurs bâtiments plus hauts que la tour willis et ils sont aussi en Chine, à
séoul, et même l'actuel
One world trade center à new york, est plus haut que la tour willis, à cause de l'antenne. puisqu'il a quelques mètres de moins si l'on s'en tient à la hauteur du dernier étage. la vérité est que la tour willis a exactement
110 étages. et le seul centre commercial mondial en compte 94, mais il est également plus tôt dans le classement des bâtiments les plus hauts, en raison de l'antenne. Comme la tour Petronas, elles sont supérieures non pas à cause du nombre d'étages mais à cause des mâts qui font partie de la structure, ce ne sont pas à proprement parler des antennes, ajoutées plus tard, c'est pourquoi elles ont été conjointement qualifiées de plus haut bâtiment du monde et a ainsi dépassé la tour willis. mais aujourd'hui je vais parler de la tour willis, qui est une ville dans la ville.
Ce dessin que j'ai réalisé moi-même peut nous donner une idée de ce qu'est le
transport vertical dans ce gigantesque bâtiment. Ce n’est pas absolument exact. mais c'est assez clair pour nous donner une idée. J'ai peint les
ascenseurs express en jaune. Il existe un nombre important d'ascenseurs qui vont directement du rez-de-chaussée aux étages intermédiaires, c'est-à-dire que n'importe quel étage allant du 33ème étage jusqu'au bas, vous pouvez accéder à n'importe lequel d'entre eux directement depuis le rez-de-chaussée. Par contre, si la destination vient du 33ème étage, alors il faut prendre un ascenseur express, qui est l'une des lignes jaunes, précisément celle de gauche, et ce groupe de 6 ascenseurs va directement au 33ème et 34ème étages, Une fois sur place, les passagers doivent changer les batteries de l'ascenseur pour monter aux différents étages 40, 50, 60, etc. Si la destination est le 70ème étage par exemple, alors vous devez prendre un autre groupe de 6 ascenseurs express depuis le rez-de-chaussée qui cette fois en moins d'une minute parcourent les 66 étages qui mènent au deuxième
skylobby du bâtiment. Une fois sur place, à l'aide d'un
escalier roulant, les passagers doivent monter jusqu'au 68ème étage et y localiser la batterie d'ascenseurs qui les mènera aux étages correspondants, c'est-à-dire aux 74ème, 85ème, 93ème, 100ème, etc. Ils doivent toujours utiliser le skylobby au 66ème étage. Le bâtiment dispose également de deux ascenseurs très directs du sous-sol au
103ème étage, où se trouve le célèbre
observatoire public, qui est l'une des attractions touristiques les plus populaires de
les États Unis. Logiquement, il existe également des ascenseurs directs et avec des arrêts à absolument tous les étages, mais ce sont des ascenseurs de service utilisés par les employés des services internes de ce géant. J'espère que vous avez apprécié cette explication et qu'avec mon dessin c'est un peu plus clair.
La construction a commencé en 1971 et en 1973, les premiers employés ont commencé à entrer. à peine deux ans et le géant était déjà construit. Le bâtiment possède le plus grand nombre d'ascenseurs dans un bâtiment au rez-de-chaussée. de là, les ascenseurs vont directement aux skylobbies situés aux étages supérieurs. un système qui a déjà été utilisé au 875 north michigan avenue et dans les célèbres tours jumelles de new york. dans la tour willis, il y a des ascenseurs directs depuis le rez-de-chaussée uniquement si vous devez vous rendre aux 28 premiers étages. donc votre bureau est au 28ème étage, vous pouvez aller tout droit, sans avoir à prendre deux ascenseurs. Il faut également garder à l'esprit que dans ce gratte-ciel, il y a 14 ascenseurs avec un système à double cabine. Ce sont les fameux skylobbies, qui reçoivent ces ascenseurs super rapides, directs, et sans aucun arrêt, sauf au 33e étage et au 66e étage.Une fois là-bas, il faut changer d'ascenseur, par un petit escalator, et prendre les ascenseurs locaux jusqu'au niveau supérieur. étages. Vous ne pouvez passer des étages 34 à 103 que si vous utilisez les ascenseurs express au préalable. il n'est pas possible d'aller directement de la rue, encore moins à des étages si hauts qu'ils ne sont desservis que par des ascenseurs express. Il n'y a que deux ascenseurs directs au 103ème étage, mais c'est exclusif pour les touristes qui visitent l'observatoire situé à cet étage.
Au 67ème étage, il y a un restaurant mais c'est pour les clients du bâtiment ou les rendez-vous précédents pour des événements spéciaux. les vues sont fabuleuses. Je pense aussi qu'au 103ème étage on peut dîner en réservant à l'avance, plus d'informations sur les pages web respectives. ce que j'ai vu est fabuleux et les vues spectaculaires pendant que l'on dîne.
Today I would like to write about a building that fascinates me. Currently, there are already many other buildings as tall as this one, or even taller. For example, the tallest tower is in Dubai, followed by the recently completed skyscraper in Kuala Lumpur, which oddly enough, in this city a few years ago the famous
Petronas Towers were built and it was they who tore off the title of tallest building. top of willis tower. Secondly, the third tallest building in the world today is the
Shanghai Tower. then there are several buildings taller than the
Willis Tower and they are also in China, in Seoul, and even the current One World Trade Center in New York, is taller than the Willis Tower, because of the antenna. since it is a few meters less if we stick to the height of the top floor. the truth is that the willis tower has exactly 110 floors. and the world's only shopping center has 94, but it is also earlier in the ranking of tallest buildings, due to the antenna. Like the Petronas Tower, they are superior not because of the number of floors but because of the masts which are part of the structure, they are not strictly speaking antennas, added later, which is why they were jointly qualified as the tallest building in the world and thus surpassed the Willis Tower. but today i'm going to talk about willis tower, which is a city within a city.
This drawing that I made myself can give us an idea of what
vertical transportation is like in this gigantic building. This is not absolutely correct. but it's clear enough to give us an idea. I painted the
express elevators yellow. There are a significant number of elevators that go directly from the ground floor to the middle floors, that is, any floor from the 33rd floor to the bottom, you can access any which of them directly from the ground floor. On the other hand, if the destination comes from the 33rd floor, then you have to take an express elevator, which is one of the yellow lines, precisely the one on the left, and this group of 6 elevators goes directly to the 33rd and 34th floors, Once on instead, passengers must change the elevator batteries to go up to different floors 40, 50, 60, etc. If the destination is the 70th floor for example, then you must take another group of 6 express elevators from the ground floor which this time in less than a minute travel the 66 floors which lead to the second skylobby of the building. Once there, using an escalator, passengers must go up to the 68th floor and locate the battery of elevators which will take them to the corresponding floors, that is to say the 74th, 85th , 93rd, 100th, etc. They must always use the skylobby on the 66th floor. The building also has two very direct elevators from the basement to the 103rd floor, where the famous
public observatory is located, which is one of the most popular tourist attractions in the United States. Logically, there are also direct elevators and with stops on absolutely all floors, but these are service elevators used by employees of the internal services of this giant. I hope you enjoyed this explanation and that with my drawing it is a little clearer.
Construction began in 1971 and in 1973 the first employees began to enter. barely two years and the giant was already built. The building has the most elevators in a ground floor building. from there the elevators go directly to the skylobbies on the upper floors. a system that has already been used at 875 north michigan avenue and in the famous
twin towers of new york. In Willis Tower there are direct elevators from the ground floor only if you need to go to the first 28 floors. so your office is on the 28th floor, you can go straight, without having to take two elevators. It should also be borne in mind that in this skyscraper there are 14 elevators with a double cabin system. These are the famous skylobbies, which receive these super fast, direct elevators, and without any stopping, except on the 33rd floor and the 66th floor. Once there, you have to change elevators, by a small escalator, and take the local elevators to the upper level. floors. You can only go from floors 34 to 103 if you use the express elevators first. it is not possible to go directly from the street, much less to floors so high that they are only served by express elevators. There are only two direct elevators to the 103rd floor, but it is exclusive for tourists who visit the observatory located on this floor.
On the 67th floor there is a restaurant but it is for guests of the building or previous appointments for special events. the views are fabulous. I also think that on the 103rd floor you can dine by booking in advance, more information on the respective web pages. what I saw was fabulous and the views were spectacular while we dined.
Oggi vorrei scrivere di un edificio che mi affascina. Attualmente esistono già molti altri edifici alti quanto questo, o anche di più. Ad esempio, la torre più alta è a Dubai, seguita dal grattacielo recentemente completato a Kuala Lumpur, che, stranamente, in questa città qualche anno fa furono costruite le famose Petronas Towers e furono loro a strappare il titolo di edificio più alto. cima della torre di Willis. In secondo luogo, il terzo edificio più alto del mondo oggi è la Shanghai Tower. poi ci sono diversi edifici più alti della Willis Tower e sono anche in Cina, a Seoul, e anche l'attuale One World Trade Center di New York, è più alto della Willis Tower, per via dell'antenna. poiché è qualche metro in meno se ci atteniamo all'altezza dell'ultimo piano. la verità è che la Willis Tower ha esattamente 110 piani. e l'unico centro commerciale al mondo ne ha 94, ma è anche primo nella classifica degli edifici più alti, grazie all'antenna. Come la Torre Petronas, sono superiori non per il numero di piani ma per i tralicci che fanno parte della struttura, non sono propriamente antenne, aggiunte in seguito, motivo per cui sono stati congiuntamente qualificati come l'edificio più alto del mondo. mondo e quindi superò la Willis Tower. ma oggi parlerò di Willis Tower, che è una città nella città.
Questo disegno che ho realizzato io stesso può darci un'idea di come sia il trasporto verticale in questo gigantesco edificio. Ciò non è assolutamente corretto. ma è abbastanza chiaro per darci un'idea. Ho dipinto di giallo gli ascensori rapidi. Ci sono un numero significativo di ascensori che vanno direttamente dal piano terra ai piani intermedi, cioè a qualsiasi piano dal 33° piano fino al fondo, a ciascuno di essi è possibile accedere direttamente dal piano terra. Se invece la destinazione arriva dal 33° piano, allora bisogna prendere un ascensore rapido, che è una delle linee gialle, precisamente quello a sinistra, e questo gruppo di 6 ascensori va direttamente al 33° e 34° piano, Una volta saliti invece i passeggeri devono cambiare le batterie dell'ascensore per salire ai diversi piani 40, 50, 60, ecc. Se la destinazione è ad esempio il 70° piano, allora bisogna prendere un altro gruppo di 6 ascensori rapidi da terra piano che questa volta in meno di un minuto percorrono i 66 piani che conducono al secondo skylobby dell'edificio. Una volta lì, utilizzando una scala mobile, i passeggeri dovranno salire al 68° piano e individuare la batteria di ascensori che li porterà ai piani corrispondenti, cioè il 74°, 85°, 93°, 100°, ecc. Dovranno sempre utilizzare la skylobby al 66esimo piano. L'edificio dispone inoltre di due ascensori molto diretti dal seminterrato al 103° piano, dove si trova il famoso osservatorio pubblico, una delle attrazioni turistiche più popolari degli Stati Uniti. Logicamente ci sono anche ascensori diretti e con fermate assolutamente su tutti i piani, ma si tratta di ascensori di servizio utilizzati dai dipendenti dei servizi interni di questo colosso. Spero che questa spiegazione vi sia piaciuta e che con il mio disegno sia un po' più chiara.
La costruzione iniziò nel 1971 e nel 1973 iniziarono ad entrare i primi dipendenti. appena due anni e il gigante era già costruito. L'edificio ha il maggior numero di ascensori in un edificio al piano terra. da lì gli ascensori portano direttamente alle skylobbies dei piani superiori. un sistema già utilizzato all'875 north michigan avenue e nelle famose torri gemelle di new york. Nella Willis Tower ci sono ascensori diretti dal piano terra solo se devi andare ai primi 28 piani. quindi il tuo ufficio è al 28° piano, puoi andare dritto, senza dover prendere due ascensori. Va inoltre tenuto presente che in questo grattacielo sono presenti 14 ascensori con sistema a doppia cabina. Sono le famose skylobbies, alle quali accedono questi ascensori super veloci, diretti e senza alcuna fermata, tranne che al 33° e al 66° piano. Una volta lì, devi cambiare ascensore, tramite una piccola scala mobile, e prendere gli ascensori locali fino al piano superiore. piani. Puoi passare dai piani 34 al 103 solo se usi prima gli ascensori rapidi. non è possibile accedere direttamente dalla strada e tanto meno ai piani così alti da essere serviti solo da ascensori rapidi. Ci sono solo due ascensori diretti al 103° piano, ma è riservato ai turisti che visitano l'osservatorio situato su questo piano.
Al 67° piano è presente un ristorante ma è riservato agli ospiti dell'edificio o previo appuntamento per eventi speciali. i panorami sono favolosi. Penso anche che al 103° piano si possa cenare prenotando in anticipo, maggiori informazioni nelle rispettive pagine web. quello che ho visto è stato favoloso e i panorami erano spettacolari mentre cenavamo.
