Table of Contents: 1. Historical background about the tall buildings. 2. Lateral Resisting Systems. 3. Using Technology in high rise building design. 4. Conclusion. 5. References

Historical Background (Why & How): In 1885,William LeBaron introduced the steel columns and frames as modern construction materials. LeBaronbuilt10-storiessteeltallbuildingcalledHomeInsurance building in Chicago. The use of steel as a construction materials and the development of elevator technologies remove the height limitations. In 1913, the Woolworth building in Manhattan was the first to reach 60 stories (242 m).This building is still in service till now.

Historical Background (Why & How): In the beginning of the twentieth centuries, the large companies recognized the advertising and publicity advantages of connecting their names to tall buildings. Chrysler building (77- stories, 319 m) and Wall Tower Building (66-stories, 290 m) are examples of tall buildings built in the name of companies. After World War II, the need for more space was the drive to build new tall buildings such as Empire State Building in New York City (381 m). The Table below summarizes examples of the current tall buildings in the world. The figure below gives pictures of tall buildings.

Historical Background (Cont.): Hight= 147 m

Historical Background (Cont.):

#BuildingCityFloorsHeightYear 1Burj KhalifaDubai m Makkah Clock Royal Tower [Abraj Al Bait] Makkah95601 m2012 3Taipei Tower (Taiwan)Taipei m Shanghai World Financial Center (China) Shanghai m International Commerce Centre [Union Square] Hong Kong m2010 6,7 Petronas Towers Kuala Lumpur m1998 8Nanjing Tower (China)Nanjing66450 m2010 9Willis Tower (Chicago)Chicago m KK100 (China)Shenzhen m2011

 There is a new Tall building under construction is called the Kingdom Tower.  It is height almost 1000m which will break the boundaries and make a new record in the tall building.

Lateral Resisting Systems: Ideally,a structural engineer should choose the most efficient structural elements to resist gravity and lateral (wind and seismic) loadings. However, ideal design conditions are rarely present. The structural engineer must accommodate a certain restrictions for the most efficient design. The efficiency of the structural systems is compared via their weight per unit floor area.

1-Rigid Frames: Deformed Shape The deformed shape of the Frame system shows that the frame has a high rigidity in the upper floors where there is a little deformation more than the lower floor.

2-Shear walls & Cores: The shear walls are primary lateral load resistance. Shearwallsactasverticalcantilevers,typicallyaroundelevator, stairs and service shafts. Shear wall are stiffer than rigid frames and are economical to about 55 stories. Whenshearwallarecombinedwithframes,thewallattractall lateral loads, so the frames is designed only for gravity.

2-Shear walls(cont.): The deformed shape of the Shear Wall system system shows that the Wall has a high rigidity in the Lower floorswherethereisa littledeformation more than the Higher floor. Deformed Shape

3-Shear Wall-frame Structures(Cont.):

4-Outrigger-Braced Structures(Cont.):

The outrigger A core inside the building  The outrigger makes a better distribution of straining actions between core and shear wall or frames.  The outrigger system also decreases the total drift of the building.  Using another outrigger in the lower floors will enhance the distribution of straining actions

4-Outrigger-BracedStructures(Cont.):

7-Framed-TubeStructures(Cont.):

8-Mega Truss Structures:

Technology vs. Civil Engineering :

The Pearl River Tower برج نهر اللؤلؤ

Technology vs. Civil Engineering :

Conclusion: The efficiency of the structural systems is compared via their weight per unit floor area. The structure engineer has to do his best to choose the most appropriate lateral system which meet architecture requirements in addition less cost and higher resistance for lateral and gravity loads by making value engineer for the proposed system and compare between the alternatives. We can make composite systems which consists of more than one of the above systems which allow us to design taller buildings that could not be designed using one system only.

References: Paulino, Madison R., “Preliminary Design of Tall Buildings” a thesis submitted to the faculty of Worcester Polytechnic Institute. Hoogendoorn, P.P., “Lateral Load Design of Tall Buildings” a master submitted to Delft University of Technology. Taranath,BungaleS.,“StructureAnalysis&DesignoftallBuildings” TH845.T Leonard, Johan, “Investigation of Shear Lag Effect in High-rise Buildings with Diagrid System” Massachusetts Institute of Technology L.A. Prieto, Portar, “Structural Forms for Tall Buildings” Florida International Univeristy 2007.