CONSTRUCTION work on the superstructure of the world’s tallest tower was due to commence last month, over an 85,000-sq-m site in Obhor north of Jeddah, Saudi Arabia, following the recent completion of the foundation works.

The $1.5-billion Kingdom Tower, which will soar to a record-breaking height of more than 1 km, is now above the ground and construction work is moving at an accelerated pace, according to the Jeddah Economic Company (JEC), owner and developer of the Kingdom Tower and Kingdom City.

The piling works for the foundation, which is one of the most important and difficult stages of the project, took 12 months to complete, says a top official of JEC.

“JEC has achieved new world records using the latest technologies for high-rise buildings foundation construction. About 270 piles were cast in situ reaching 105 m below natural ground level and with diameters that vary between 1.5 and 1.8 m,” says Mounib Hammoud, the CEO of JEC.

The raft is considered one of the world’s largest one-piece reinforced steel foundations with a thickness ranging between 4.5 to 5 m.

The tower ... viewed from the side and from the air.

“Both piles and raft are supported with anti-corrosion technologies to preserve the steel reinforcement using cathodic protection. In addition, strain gauge instrumentation and load cells have been built-in to detect any changes in the soil and provide continuous readings about any environmental changes to the area around the foundations. Finally, earthing and lightning prevention systems were installed into the raft piling foundation.”

He continues: “Some of the techniques specified include the use of high-strength concrete reaching cylinder compression of 85 MPa. The reinforced steel used is deformed bars Grade 60 and up to 40 mm in diameter and with yield strength of 520 MPa.

The piling work on the project was completed in December by ground engineering specialist Saudi Bauer. Fugro completed detailed ground investigations and specialist foundations testing for the supertall tower.

The Kingdom Tower is being built in accordance with the highest construction standards using the most advanced techniques, with specifications surpassing what is usually required, says Hammoud.

Raft piling works ... completed.

The main contractor on the project is Saudi Binladin Group and the architect is the US-based Adrian Smith+Gordon Gill Architecture (AS+GG).

The stunning, sleek and gleaming silvery grey tower scores well in the green league in terms of its environmentally-efficient design, energy and water usage, carbon footprint and other sustainable issues, Adrian Smith, a partner at AS+GG told Gulf Construction (Gulf Construction, May 2012).

AS+GG’s design for Kingdom Tower is both highly technological and distinctly organic. “With its slender, subtly asymmetrical massing, the tower evokes a bundle of leaves shooting up from the ground – a burst of new life that heralds more growth all around it,” says Smith.

The sleek, streamlined form of the tower can be interpreted as a reference to the folded fronds of young desert plant growth. “The way the fronds sprout upward from the ground as a single form, then start separating from each other at the top, is an analogy of new growth fused with technology,” he says.

While the design is appropriate to the Saudi context, it also represents an evolution and a refinement of an architectural continuum of skyscraper design. The three-petal footprint is ideal for residential units, and the tapering wings produce an aerodynamic shape that helps reduce structural loading due to wind vortex shedding.

The drop-off area ... high class finishes.

“The Kingdom Tower’s design embraces its architectural pedigree, taking full advantage of the proven design and technological strategies of its lineage, refining and advancing them to achieve new heights,” Smith says.

The result is an elegant, cost-efficient and highly constructible design that is grounded in built tradition and aggressively forward-looking, taking advantage of new and innovative thinking about technology, building materials, life-cycle considerations and energy conservation, he adds.

In designing the finer details of the Kingdom Tower, the Chicago-based AS+GG is leading an interdisciplinary team that also includes renowned consultant Thornton Tomasetti, the engineer on three of the world’s top 10 tallest buildings and the building services engineering consultant Environmental Systems Design (ESD).

The Kingdom Tower features 170 storeys, seven of which will be allocated for the five-star Four Seasons Hotel offering 200 rooms, eleven storeys for 121 luxury serviced apartments, and seven storeys for offices. The tower will also have 61 storeys that include 318 housing units of various types, a gym, spa, cafes and restaurants, several sky lobbies and the world’s highest observation floors located on the top floors at a height of 660 m, enabling visitors to view the city of Jeddah from the sky.

A further double-height eight full refuge floors that are fire resistant will be allocated throughout the tower.

The skyscraper will feature a sky terrace – roughly 30 m in diameter – at level 157, which will be an outdoor amenity space intended for use by the penthouse floor.

The tower will have 58 high-speed elevators including the double-decker high-speed elevators reaching a speed of 12 m per second, in addition to other distinctive features, making the Kingdom Tower an iconic landmark of Saudi Arabia.

Construction of the tower is expected to five years to complete.

Located on an area of more than 5.3 million sq m, the Kingdom City will provide a contemporary lifestyle environment supported by an integrated advanced infrastructure. The city is designed to be a vital point for business and trade, as well as being a tourist hotspot.

“The main objective of developing the Kingdom City is to provide a unique environment to live, work and play and offering residents and visitors elevated service levels. The city will significantly enhance Jeddah’s global status as a dynamic business, commercial, educational, medical and entertainment hub and will contribute to consolidating the sustainable growth of Jeddah’s real estate development,” says Hammoud.