GEOTECHNICAL REPORT FOR

HIGH RISE BUILDING BURJ KHALIFA

CASE STUDY : BURJ KHALIFA

The Burj Khalifa in October 2012

Former names

Burj Dubai

Record height

Tallest in the world since 2010[I]

Preceded by Taipei 101General information

Type Mixed-useArchitectural style

Neo-futurism

Location 1 Sheikh Mohammed bin Rashid Boulevard,Dubai, United Arab Emirates

Coordinates 25°11 49.7″N55°16 26.8″E′ ′ Coordinates: 25°11 49.7″N 55°16 26.8″E′ ′

Construction started

6 January 2004

Completed 30 December 2009

Cost USD $ 1.5 billion[2]

Height

Architectural 828 m (2,717 ft)[3]

Tip 829.8 m (2,722 ft)[3]

Roof 828 m (2,717 ft)

Top floor 584.5 m (1,918 ft) (Level 154)[3]

Observatory 555.7 m (1,823 ft) (Level 148)[3]

Technical details

Floor count 154 usable floors[3][4]

plus 9 maintenance levels, 46 spire levels,[5] and 2 below-ground parking levels

Floor area 309,473 m2(3,331,100 sq ft)[3]

Lifts/elevators 57 (55 single deck and 2 double deck), made by Otis Elevator Company

Architect Adrian Smith at SOM

Developer Emaar Properties[3]

Structural engineer

Bill Baker at SOM[6]

Main contractor

Samsung C&T Corporation, Besix andArabtecSupervision Consultant Engineer & Architect of Record Hyder ConsultingConstruction Project Manager Turner ConstructionGrocon[7]

Planning Bauer AGand Middle East Foundations[7]

Lift contractor Otis[7]

VT consultant Lerch Bates[7]

INTRODUCTION

• The Burj Dubai Project is a multi-use development tower with a total floor area of 460,000 square meters that includes residential, hotel, commercial, office, entertainment, shopping, leisure, and parking facilities. The Burj Dubai project is designed to be the centerpiece of the large scale Burj Dubai Development that rises into the sky to an unprecedented height that exceeds 700 meters and that consists of more than 160 floors. The Client of Burj Dubai Tower, Emaar Properties, is a major developer of lifestyle real estate in the Middle East.

Turner International has been designated by the owner as the Construction Manager, and Samsung Joint Venture (consisting of Samsung, Korea base contractor; Besix, Belgium base contractor; and Arabtec, Dubai base contractor) as the General Contractor. The design of Burj Dubai Tower is derived from geometries of the desert flower, which is indigenous to the region,and the patterning systems . The modular Y-shaped building, with a setback at every seventh floor, was part of the original design concept that allowed Skidmore, Owings and Merrill to win the invited design competition. The tower superstructure of Burj Dubai is designed as an all reinforced concrete building with high performance concrete from the foundation level to level 156, and is topped with a structural steel braced frame from level 156 to the pinnacle. The tower massing is also driven by wind engineering requirements to reduce dynamic wind excitation. As the tower spirals into the sky, the building’s width and shape diminish, thus reducing wind dynamic effects, movement, and acceleration. Integrating wind engineering principals and requirements into the architectural design of the tower results in a stable dynamic response,, taming the powerful wind forces.

FOUNDATION • The foundation system for the Burj Dubai is comprised of 192

bored piles . 1.5-m (approximately 5-ft) in diameter and approximately 50-m deep (164-ft). A 3.7-m (12-ft) thick raft foundation sits on top of the piles under the full footprint of the structure.

• The Tower is founded on a 3700mm thick high performance reinforced concrete pile supported raft foundation . The reinforced concrete raft foundation utilizes high performance Self Compacting Concrete (SCC) and is placed over a minimum 100mm blinding slab over waterproofing membrane, over at least 50mm blinding slab. The raft foundation bottom and all sides are protected with waterproofing membrane

FOUNDATION• Raft Foundation System (Raft foundation is a thick

concrete slab reinforced with steel which covers the entire contact area of the structure like a thick floor. Sometimes area covered by raft may be greater than the contact area depending on the bearing capacity of the soil underneath. The reinforcing bars runs normal to each other in both top and bottom layers of steel reinforcement. ). The piles are 1500mm diameter, high performance reinforced concrete bored piles, extending approximately 45 meters below the base of the raft. pile capacities of 3000Tonnes.

STRUCTURE SYSTEM

SITE PLAN

• landscape design process Site planning generally begins by assessing a potential site for development through site analysis. Information about slope, soils, hydrology, vegetation, parcel ownership, orientation, etc. are assessed and mapped. By determining areas that are poor for development (such as floodplain or steep slopes) and better for development, the planner or architect can assess optimal location and design a structure that works within this space

Now site plan of burj khalifa

• The Burj Dubai site area is approximately 105,600m2 and encompassing the tower, the office annex, the pool annex, and the parking areas, divided into three zones (Zone A, Zone B, and Zone C). The site logistic works and planning works are constantly evolving to reflect current construction activities, lay-down areas, site traffic circulation, etc.

IMPORTANCE OF GEOTECNICAL REPORT:

• The Geotechnical report provides critical and vital information for the owner, architect, design engineer, and the contractor to use and evaluate. A foundation failure of a major structure is measured in millions of dollars and ruined careers. The drilling was carried out using cable percussion techniques with follow-on rotary drilling methods to depths between 30m and 140m below ground level. The quality of core recovered in some of the earlier boreholes was somewhat poorer than that recovered in later boreholes, and therefore the defects noted in the earlier rock cores may not have been representative of the actual defects present in the rock mass. Phase 4 of the investigation was targeted to assess the difference in core quality and this indicated that the differences were probably related to the drilling fluid used and the overall quality of drilling Standard Penetration Tests (SPTs) were carried out at various depths in the boreholes and were generally carried out in the overburden soils, in weak rock or soil bands encountered in the rock strata.

SOIL INVESTIGATION • Before the building could be constructed, two years of ground

work had to be laid, including 6 months of geotechnical investigation and testing, and a year and a half of excavation and foundation construction. There were many challenges faced by the geotechnical team in the construction of the tower. These included the unique architectural design of the building footprint itself, the generally weak soil of the construction site and the overall size of the structure, creating massive loads on the foundation. As with most large buildings, the Burj Khalifa uses a deep foundation design, consisting of both a 3.7 meter thick raft foundation and 192 bored piles.

. The purpose of this design is to allow the weight of the building to be spread over a larger volume of soil, decreasing the load in any given portion. Bored piles are piles cast into drilled holes in the ground on site. This allowed the engineers of the project to both create variable length piles depending on the loads the pile is expected to bear, and to disturb the already weak soil much less than a traditional driving of piles would. Where these piles would go and all their various properties were determined after very extensive soil testing. 23 boreholes were drilled around the construction site and extensive testing was performed in the area in and around where the foundation would be placed, including inside the boreholes themselves. This found that the soil was dominated by loose sands near the surface, and weak sand stones and siltstones underneath. Because of the weak soil conditions, many large and very deep piles were needed to properly stabilize the structure.

. The precise dimensions of the piles vary with the locations around the site, but generally are 1.5 meters in diameter, and 50 meters long for the building, and 30 meters long for the surrounding plaza and podium. The final problem faced in the foundation design was simply the large weight and size of the building. This created large loads that had to be distributed between the slab and the piles. With an empty weight of over 500,000 metric tons pushing down and a building height of over 800 meters acting as a lever arm for the high speed winds, the loads on the foundation are astronomical, reaching a maximum of 37 Mega Newton's per pile on one side. This is equivalent to over 5 and a half fully loaded Airbus A380’s stacked on top of each other. But despite this massive weight, the incredible engineering put into pile and slab design has kept the building from settling even three inches.