Article #4: Safety First!

City blast injures workers

Two construction workers were taken to hospital suffering burns and shock after an electrical explosion in Melbourne's inner city yesterday. Read it more here, click link.

http://www.theage.com.au/news/national/city-blast-injures-workers/2007/06/04/1180809394251.html?s_cid=rss_age

The Petronas Twin Towers, Kuala Lumpur, Malaysia.

The Petronas Twin Towers

Architect: Cesar Pelli

Location: Kuala Lumpur, Malaysia

Building Type: Skyscraper, commercial office tower
Construction System: Glass, steel, and concrete
Climate: Tropical
Context: urban
Style: Modern Architecture

The Petronas Twin Towers were the tallest buildings in the world from April 15th, 1996 until October 17th, 2003 when Taipei 101 (Financial Center) was topped out at 508m (1676ft). The 88-storey Petronas Twin Towers, developed as an integral part of the Kuala Lumpur City Centre (KLCC) project, house PETRONAS' new corporate headquarters.

Completed in 1997, the Twin Towers are a striking glass-and-steel combination with floor plans based on an eight-pointed star. The Towers were designed to symbolize strength and grace using geometric principles typified in Islamic architecture. The towers are also joined at the 41st and 42nd floors (175m above street level) by a 192ft-long (58.4m) double-decker skybridge - linking the two sky lobbies and facilitating the movement between the two towers.

Construction

The building was constructed in the middle of the city centre. It brought together the world's leading practitioners of engineering, building technology and construction. Construction planning began in January 1992. By March 1993, the excavators were hard at work digging down to 30 metres below the surface of the site. The extent of excavation required over 500 truck-loads of earth to be moved every night.

The next stage was the single largest and longest concrete pour in Malaysian history: 13,200 cubic metres of concrete was continuously poured through a period of 54 hours for each tower. This record-breaking slab, together with 104 piles forms the foundation for each of the towers. From this floor rose a 21-metre high retaining wall, with a perimeter length of over 1 kilometre. This concrete shell and the basement area it enclosed required two years of up to 40 workers on site all day and night.

As an added consideration, two different contractors were chosen for each tower to allow cross-monitoring of construction values and techniques – with one coming to the aid of the other should problems arise. The construction of the structure commenced in April 1994, after rigorous tests and simulations of wind and structural loads on the design. The 'composite' structure of the Towers employs both the flexibility of steel and the rigidity of high-strength concrete.

Each component material was used to best effect in constructing the 452 m-high buildings. About 80,000 cubic metres of high strength concrete with 37,000 tons of steel were used to form the frames of both Towers. Of particular importance was maintaining the verticality of the structures throughout the full height as they were being built. The reason for this, besides reinforcing the aesthetic design, were to ensure structural load integrity and the safe passage of the high-speed double-decker elevators.

The determination of verticality was monitored by international specialist surveyors who, with the aid of global positioning systems, checked alignments every day and every night. The same surveyor used the same instrument at the same time in every 24 hours, thereby minimising any element of differences in judgment. Construction works were done primarily at night and finishing works were done primarily during the day (to minimize the cost of artificial lighting). As a result, the entire management and construction team redefined the Malaysian industry standard of 'fast-track'.

The PETRONAS Twin Towers were finally encased in steel and glass and could be viewed as complete in June 1996.

Reference:
http://www.emporis.com/en/wm/cx/?id=petronastwintowers-kualalumpur
http://www.petronastwintowers.com.my/internet/pett/pettweb.nsf/frm_home_hi?OpenFrameset

Updates!

I've updated some of the site visits and articles. which they are in my April/May blog folder. so check it out! or just browse through my older posts.. thank you!