What are the control joints of reinforced concrete structures?

The control joint of reinforced concrete structure refers to the expansion joint, settlement joint and seismic joint between two adjacent buildings or two parts of buildings to avoid temperature expansion and contraction, foundation settlement and earthquake collision. It is defined in the Code for Design of Concrete Structures: the general term for dividing concrete structure intervals according to structural design requirements.

According to the function, it can be divided into the following ten types:

Expansion joint (extension joint): a structural joint that can effectively eliminate expansion (elongation) deformation in statically indeterminate structures; ?

Shrinkage joint: a structural joint that can effectively eliminate shrinkage (shortening) deformation in statically indeterminate structures; ?

Settlement joints: structural joints that can effectively eliminate poor deformation caused by uneven settlement of foundation in statically indeterminate structures;

Anti-seismic joint: When the structure is forced to move under the action of earthquake, the collision damage of different parts of the structure can be eliminated and alleviated; ?

Body joint: when the shape or volume of the structure changes suddenly, the structure is divided into different parts at the sudden change of body shape;

Local joints: set local structural joints in the position where the structural shape changes suddenly to reduce the influence of stress concentration; ?

Control joint: the joints that are prone to cracks in the structure are actively guided and controlled by pre-setting weak sections or other measures;

Flat-seam: the seam formed at the splicing place when prefabricated components are assembled and connected;

Construction joint: when the volume of concrete pouring is large, divide different construction pouring areas according to the predetermined position and connect the formed joints; ?

Interface joint: the joint formed on the interface between different structural forms, different building components and different building materials.