Q. Location of construction joints?

Construction joints are generally required in construction works since there is limited supply of fresh concrete in concrete batching plants in a single day and size of concrete pour can be too large to be concreted in one go. 

The number of construction joints in concrete structures must be minimized. If construction joints are required to facilitate construction, it is usually aligned perpendicular to the direction of the member. For slabs andbeams, construction joints are predominantly located at about one-third of the span length. Choice of this location is based on the consideration of low bending moment estimatedwith relatively low shear force. Though location of one-third span is not applicable to simply supported slabs and beams since this location is expected to have considerable shear forces and bending moment when subjected to design loads. Occasionally engineers can tend to select the end supports as locations for construction joints just to simplify construction.