Seismic Performance of Flat Slab Column Building

Flat slab building systems are getting popularity in India because it offers distinct advantages such as low cost due to ease of construction (e.g. slip forms), low floor to floor height, and flexible use of space. Hence this kind of system is generally used for office and parking areas. In Flat slab buildings the load is transferred directly from slab to columns without beams but when slab encounter any opening or discontinuity than beams are used such as around lift core ,discontinuous edges of slab, etc. Flat slabs with drop panels or column heads are generally constructed as these extra projections provide safety against punching shear and also reduce the heavy negative moment. If no drop panel are provided than that system is called Flat Plat (Fig 1.1) which are more economical in construction as compared with Flat slabs. This system performs well in resisting gravity or vertical loads but performs poorly during cyclic loading and hence many Building codes around the world has rejected the application of this building system in active earthquake zones keeping in mind the past failures of these types of buildings during major earthquakes.

https://docs.google.com/document/d/1nGCxGIfTBuPyTdD7XPy1Jt69OZiWmhQ4YICQts8HjAc/edit?ndplr=1

Burj Dubai ::world’s supertall sky-scraper

Burj Dubai ("Dubai Tower") is currently under construction in Dubai, United Arab Emirates. When it is completed in late 2009, it is predicted to be the tallest man-made structure in the world. Scheduled for occupancy in September 2009, the building is part of a 2 km² (0.8 sq mi) development called 'Downtown Dubai' Project.
The total budget for the Burj Dubai project is about $4.1 billion US and for the entire new 'Downtown Dubai', $20 billion US.

Burj Dubai Tower
Architect - Skidmore, Owings & Merrill LLP
Developer - EMAAR Properties
Contractor - Samsung Constructions / BESIX / Arabtec
Construction - Steel Reinforced Concrete / Steel Spire
Rendering - UV Solar Glass / Aluminum / Stainless Steel
Floors - 216 above ground floor plates / 164 occupied floors
Height - 818m / current design
(Proposed height not released officially)
Elevators - Fastest in the world with a speed of 1050m/min
Completion due - 6th August 2009
Website-http://www.burjdubai.com/

• The tower is being constructed by a South Korean company, Samsung Engineering & Construction which also built the PETRONAS Twin Towers and the Taipei 101.


• The tower is designed by Skidmore, Owings and Merrill, who also designed the Sears Tower in Chicago and the Freedom Tower in New York City.


• The design of Burj Dubai is reminiscent of the Frank Lloyd Wright vision for The Illinois, a mile high skyscraper designed for Chicago, Illinois. The building resembles the bundled tube form of the Sears Tower, but is not a tube structure.

Purpose:
Burj Dubai has been designed to be the centerpiece of a large-scale, mixed-use development that will include 30,000 homes, nine hotels such as the Burj Dubai Lake Hotel & Serviced Apartments, 0.03 km² (0.01 sq mi) of parkland, at least 19 residential towers, the Dubai Mall, and the 0.12 km² (0.05 sq mi) man-made Burj Dubai Lake.

The silvery glass-sheathed concrete building will give the title of Earth's tallest free-standing structure to the Middle East — a title not held by the region since 1311 AD when Lincoln Cathedral in England surpassed the height of the Great Pyramid of Giza, which had held the title for almost four millennia.

The decision to build Burj Dubai is reportedly based on the government's decision to diversify from a trade-based economy to one that is service and tourism-oriented. According to officials, it is necessary for projects like Burj Dubai to be built in the city to garner more international recognition, and hence investment.
Sheikh Mohammed bin Rashid Al Maktoum wanted to put Dubai on the world map with something really sensational.

Facts and Figures:
 The design of Burj Dubai is ostensibly derived from the patterning systems embodied in Islamic architecture, with the triple-lobed footprint of the building based on an abstracted version of the desert flower hymenocallis.
 The tower is composed of three elements arranged around a central core. As the tower rises from the flat desert base, setbacks occur at each element in an upward spiraling pattern, decreasing the cross section of the tower as it reaches toward the sky. At the top, the central core emerges and is sculpted to form a finishing spire.
 A Y-shaped floor plan maximizes views of the Persian Gulf. Viewed from above or from the base, the form also evokes the onion domes of Islamic architecture.
 The exterior cladding of Burj Dubai will consist of reflective glazing with aluminum and textured stainless steel spandrel panels with vertical tubular fins of stainless steel. The cladding system is designed to withstand Dubai's extreme summer temperatures.
 The interior will be decorated by Giorgio Armani. An Armani Hotel (the first of its kind) will occupy the lower 37 floors. Floors 45 through 108 will have 700 private apartments on 64 floors.
 Corporate offices and suites will fill most of the remaining floors, except for a 123rd floor lobby and 124th floor (about 440 meters (1,444 ft)) indoor/outdoor observation deck. The spire will also hold communications equipment. An outdoor zero-entry swimming pool will be located on the 78th floor of the tower.
It will also feature the world's fastest elevator, rising and descending at 18 m/s (40 mph). The world's current fastest elevator (in the Taipei 101) travels at 16.83 m/s (37.6 mph) . A total of 56 elevators will be installed that can carry 42 people at a time and are double-deck elevators.
 Engineers rotated the building 120 degrees from its original layout to reduce stress from prevailing winds. Over 45,000 m³ (58,900 cu yd) of concrete, weighing more than 110,000 tones (121,000 ST/108,000 LT) were used to construct the concrete and steel foundation, which features 192 piles buried more than 50 m (164 ft) deep.

Construction:
Burj Dubai is made from reinforced concrete. As construction of the tower progresses, it becomes increasingly difficult to vertically pump the thousands of cubic meters of concrete that are required.
 The previous record for pumping concrete on any project was set during the extension of the Riva del Garda Hydroelectric Power Plant in Italy in 1994, when concrete was pumped to a height of 532 m (1,745 ft).
 Burj Dubai now holds this record as of August 19, 2007, as it has a height of 536.1 m (1,759 ft), to hold the record for concrete pumping on any project; and as of October 2, 2007 concrete was pumped to a delivery height of 588 m (1,929 ft).
 Special mixes of concrete are made to withstand the extreme pressures of the massive weight of the tower; each batch of concrete is tested and checked to see whether it can withstand certain pressures. The concrete pumps, pipelines and booms are provided by Putzmeister AG of Aichtal, Germany .
 As the consistency of the concrete on the project is essential, it was difficult to create a concrete that could withstand the thousands of tones bearing down on it, but also to withstand Gulf temperatures that can reach 50 °C (122 °F).

 To combat this problem, the concrete is not poured during the day. Instead, ice is added to the mixture and it is poured at night when it is cooler and the humidity is higher. A cooler concrete mixture cures evenly throughout and therefore is less likely to set too quickly and crack. Any significant cracks could put the whole project in jeopardy.

Future Trends:
Burj Dubai's potential competitors are:
The proposed Murjan Tower, in Manama, Bahrain. It is expected to be 1,022 m (3,353 ft) in height with 200 floors
The proposed 1,001 m (3,284 ft) Burj Mubarak al-Kabir to be erected in Kuwait as part of a massive development project called Madinat al-Hareer (City of Silk).
Another proposed tower which may surpass the height of Burj Dubai , is Al Burj (The Tower), near Dubai Marina. Speculation has suggested various heights between 700 m (2,297 ft) and 1,200 m (3,937 ft), but the developer is keeping the final height tightly under wraps. If built, it will be only 22 km (14 mi) from the Burj Dubai site.
India is joining this race with proposed under construction “Palaris Royale Tower” Worli,Mumbai with a 320 m height.

Case Study of LUPU Bridge

WORLD’S LONGEST ARCH BRIDGE LUPU BRIDGE (shanghai)

LUPU BRIDGE INTRODUTION :

• The Lupu Bridge of Shanghai is the longest steel arch bridge in the world. Its 550-meter-long arch span is 32 meters longer than that of the New River Gorge Bridge in the US state of West Virginia.
• Lin Yuanpei was the chief designer of the bridge.
• With 2.2 billion yuan (US$266 million) of investment. A six lane bridge Construction began in October 2000 and it was completed in June 2002.
• Main contractor was Shanghai Tongzhu Engineering Pvt Ltd.
• Similar to the Sydney Harbour Bridge, the Lupu Bridge also functions as a sightseeing attraction.
• The viewing platform of the Lupu Bridge is installed at the top of its giant-bow-like arch lib. Sightseers are to take the high-speed transparent elevator up to the main deck of the bridge, walk up the steps of the pathway along the arch rib—the back of this “giant-bow”- for about 280 meters, reaching the viewing platform about the size of a basketball field.

STRUCTURAL DETAILS:
Lupu Bridge is a half-through suspension arch bridge with the main span of 550 meters.

• The entire whole-steel arch-beam combined structure is composed of steel box arch ribs, orthotropic steel girder, spatial steel hangers, inclined steel columns, steel box bracings between two ribs, and horizontal post-tensioning strands.
• Two inclined arch ribs are 100 meters high from the bottom to the crown and have the cross section of rectangular steel box with the 5-meter width and the depth of 6 meters at the crown and 9 meters at the rib bases.
• The orthotropic steel girder provides six lane carriageways in the center of the deck and two sightseeing pedestrian ways on both sides, which are supported on arch ribs with some hangers and columns.
• There are several horizontal post-tensioning strands in both sides of the girder between the cross beams of both ends of the bridge girder to balance the dead load thrusts from the arch ribs of the central span.

THE LUPU TOP TEN:

1. The longest arch bridge in the world. Its 550-meter-long arch span.
2. The first ever box-arch bridge in the world. The section area of the main arch also sets a record: 9 meters high, 5 meters wide. The main arch is made up of 27 sections.
3. The first major arch bridge to be connected exclusively by welding. The length of on-site welding totals more than 40,000 meters—comparable to the total length of the inner-city elevated freeway of Shanghai.
4. The heaviest lifting weight of single component (860 tons), plus the heaviest lifting weight over the arch rib in a river (480 tons).
5. The most complicated and multiple technologies used in the construction of the main bridge, combining three distinctive methods of bridge-building technology: cable-stay, arch and suspension.
6. The volume of steel used in an arch bridge: more than 35,000 tons. It equals the steel used in building three 70,000-ton vessels.
7. The volume of steel used for the control towers building process: more than 11,000 tons in the construction of a single arch bridge.
8. The 16 horizontal staying cables used in the bridge-building are the longest (760 meters), thickest (18cm in diameter), heaviest (110-ton each) and with the greatest tension-pull tonnage (over 1700 tons) in the world.
9. The greatest thickness of on-site steel plates welding (100mm) in the construction of a steel bridge in the world.
10. The structure is designed to withstand a Force-12 hurricane, and can meet the challenge of an Earthquake that happens once in 3,280 years.