Many different structural systems are used in architecture. The type of system used depends on the building's needs. The height of the building, its load bearing capacity, the soil specifications and the building materials all dictate the proper structural system needed for a building. In particular, structural systems have evolved to focus on building up as undeveloped land has become scarce.
A wood frame is a type of lightweight structural system. Wood frame constructions are frequently used for office buildings, schools, government buildings, retail buildings, apartments and homes. Buildings with wood-based structural systems are strong and lightweight, which make them very stable in areas that experience earthquakes. How strong the wood is depends on the condition of the wood frame, any knots or splits in the wood, the moisture content of the wood and the direction of the grain.
Precast concrete can be used as part of a structural system or as a complete structural system. A precast system uses precast columns, load bearing precast walls, hollow core or double tee flooring and beams with cladding. Precast systems offer several advantages because they are fast to construct. The precast sections can be made as soon as the builder obtains the permits, and then the building can be erected immediately. This fast construction makes it possible to speedily enclose the building so interior tradesmen can start work sooner.
Steel and Concrete
Steel and concrete structural systems are a type of composite system. This type of system can combine structural steel framing with concrete tubes or concrete shear walls with a steel frame. This system is frequently used to construct tall buildings, such as high-rises. The steel and concrete can resist stress from wind and gravity.
A shear frame structural system is one in which the joints are placed in orthogonal directions. This helps the building resist wind force from any direction. The wind resistance is due to bending of the frame columns and shears. Many times these systems create grid-like surfaces, particularly when lightweight building material is used. Ultimately, deeper frames mean less bending. This is because more force is transferred to the bottom of the building. However, at some point the deepness of the frame will interfere with other building components, such as ductwork and HVAC systems.
Flat Plate System
The flat plate system was one of the first systems used in high-rise buildings. This system uses shear heads or reinforced steel at the columns, and then flat plates between the columns. These flat rate plates are typically made of concrete and modern versions can be precast. The design uses bars that form concentric rings that are then strengthened with orthogonal and diagonal bars between the columns. The thickness of the plate is a main factor in determining the load bearing of the frame.