types of support and support reactions

1. Frictionless support

-------> the reactions act normal to the surface at the point of contact as shown

2. Roller and Knife edge support

-------> the rollr and knife edge restricts the motion normal to the surface . so reactions act normal to the surface at point of contact as shown

3. Hinged support

-------> restricts the motion of the beam vertically as well as horizontally .thus there are 2 independent reactions R_1x and R1y acting on point of contact . these 2 rectangular components can be combined into a single force R1 at any unknown direction .

in general if the body acted upon is in equilibrium under the action of three no parallel forces they must pass pass through same point hence direction of R1 can be determined.

as shown

4. Built in support

-------> one end is embedded in the concrete , it restricts the motion of the end horizontal and verticle direction s. It also restricts the rotation of the beam AB about the point of contact .

so reactions R1x and R1y are exerted accompanied by a reaction couple C1

as shown