Composite Construction 1 Introduction to composite construction of buildings General 2 Steel and concrete These two materials complete one another:  Concrete is efficient in compression and steel in tension  Concrete encasement restrain steel against buckling  Protection against corrosion and fire  Steel bring ductility into the structure General 3 Aspects for using composite structures:  Architectural  Economical  Functionality  Service and Flexibility  Assembly Aspects for using composite structures 4 Architectural:  Longer spans  Thinner slabs  More slender column  More generous opportunities for design Aspects for using composite structures Economical: 5  Reduction of height reduces the total of the building --> saving area of cladding  Longer spans with the same height --> column free rooms  Additional storeys with the same total height of building  Quicker time of erection:  Saving costs, earlier completion of the building   Lower financing costs Ready for use earlier thus increasing rental income Aspects for using composite structures 6 Functionality:  Fire protection by using principles of reinforced concrete in which the concrete protects the steel Aspects for using composite structures 7 Service and building flexibility:  Adaptable structures  Modification during the life of the building  Modify services without violating the privacy of other occupants  Accommodation of service facilities in the ceiling within a false floor in a coffer box running along the walls Aspects for using composite structures 8 Assembly:  Working platforms of steel decking  Permanent shuttering   Reinforcement of profiled steel sheetings Speed and simplicity of construction  Quality controlled products ensure greater accuracy Construction methods 9 Traditionally two counteracting methods of construction could be observed both connected with special advantages but also disadvantages worth mentioning.  Conventional concrete  Construction in steel construction method + freedom of form and shapes + easy to handle + high ratio between bearing capacity and weight + prefabrication + thermal resistance + high accuracy - time-consuming shuttering - low fire resistance - sensitive on tensile forces - need of higher educated personal Construction methods 10  Composite Construction comparing these two methods a combination of both presents the most economic way + higher bearing capacity + higher stiffness + plastic redistribution Construction elements 11 composite slab composite column composite beam floor = beam + slab Construction elements 12 Composite slabs  Reinforced concrete slab in-situ concrete on shuttering partially prefabricated slabs fully prefabricated slabs Construction elements 13 Slabs  Pre-stressed concrete slabs Construction elements 14 Slabs  Profile steel sheeting Interlock between steel and concrete frictional mechanical end anchorage Construction elements 15 Beams  Conventional and innovative composite beams Construction elements 16 Beams  Types of shear connectors Construction elements 17 Columns  Examples of composite columns Construction elements 18 Joints  Example of vertical shear transfer between beam and column bracket for the lower flange reinforcement weld seam removed after concreting contact piece bracket with shear connectors shot-fired nails Examples 19 Millennium Tower (Vienna - Austria)      55 storeys Total height 202 m Total ground floor 38000 m2 Capital expenditure about 145 million Euro Time of erection: 8 months Examples 20 Millennium Tower (Vienna - Austria) 42,342,3 m m Concrete slab Concrete core Composite Slim floor beams Composite frame Composite columns Examples 21 Millennium Tower (Vienna - Austria) Total time of erection: 8 month max. speed 2 to 2.5 storeys per week! Examples 22 Citibank Duisburg (Duisburg - Germany)  15 storeys Total height 72 m  Total ground floor 14500 m2  Examples 23 Parking deck “DEZ” (Innsbruck - Austria)  4 storeys  Ground dimensions 60 x 30 m Max. span length 10.58 m with 26 cm slim floor slab (= l/40)  Examples 24 Parking deck “DEZ” (Innsbruck - Austria) Erection of composite columns over 2 storeys Assembly of prefabricated concrete slabs Examples 25 60 260 200 Parking deck “DEZ” (Innsbruck - Austria) Cross section of the slim-floor beam and slab -200 mm concrete slab -60 mm prefabricated concrete elements -steel beam: web 165/20 mm flange 245/40 mm -headed studs: 22 mm Concluding summary 26 Composite construction is popular for buildings because of following aspects:  Economy  Architecture  Functionality  Service and building flexibility  Assembly