Tall Buildings Structural Design Of Concrete Buildings Up to 300m tall
Tall buildings are now a common feature on the skyline of many cities throughout the world with concrete as
the predominant building material used in their construction.
Concrete provides a strong, durable, economic and versatile material which can be engineered to respond to demands placed on it when used in the foundations, columns, walls and floors of tall buildings.
The design and detailing of tall buildings requires detailed knowledge, experience and expertise to properly understand their behaviour.
Guidance on the design of tall buildings is provided in many of the national codes and standards however as the clients, architects and engineers push the boundaries of what is possible our understanding of the structural behaviour is constantly being updated.
Cladding is prefabricated panels that are attached to the structural frame of the building. The main function of cladding is to prevent the transmission of sound, provide thermal insulation, create an external facade, and prevent the spread of fire.
There are different cladding systems, such as curtain wall, metal curtain, stone cladding, brick claddings, precast concrete, and timber cladding.
Cladding systems are non structural elements. However, cladding can play a structural role in transferring wind loads, impact loads, and self-weight back to the structural framework. In particular, wind causes positive and negative pressure on the surface of buildings, so cladding must be designed to have adequate strength and stiffness to resist this load, both in terms of the type of cladding selected and its connections back to the structure.
Particularly in tall buildings, the wind pressure on the glazing is one of the important design considerations, this is because if one glazing fails, when it is fallings off, it will also hit the glazing on the below floors, which will cause a continues failure of the glazing.
Fig.1 shows the typical connection between the facade to structural members. On tall buildings, access systems must be provided to cladding system allowing regular inspection, maintenance, cleaning, and replacement (in particular, replacement of external seals).
Fig.1.Connection details of cladding to structural members
Curtain wall are used widely for tall buildings. Typically, curtain wall systems comprise a light weight frame onto which glazed or opaque infill panels can be fixed. These infill panels are often described as ‘glazing’ whether or not they are made of glass as shown in Figs.2 and 3.
Fig.2.A typical cladding of a tall building in Hague, Netherland
Fig.3. A glass curtain wall example of a building in Delft, Netherland
The frames play an important role in transferring loads back to the primary structure of the building and accommodating differential movement and deflection. Therefore, needs to be designed in detail. In some companies, therefore special fac ade design team to handle it.
