The culvert having one or more square or rectangular opening and their floor and top slabs are monolithically constructed with abutments and pier is referred to as box culvert.
- Box culverts are four-sided rectangular structures, the lower side pressed into the ground below, the top serving as the roadway and the lateral sides supported by the soil on either side of the obstruction.
- A box culvert may be constructed with a single box, or multiple box cells placed side by side.
- The typical size of the boxes is 3’x2’ or 12’x12’ in 1’ span and rise increments. (Usually comes in lengths of 6’ and 8’).
- Standard design: ASTM C 1433.
- Velocity of flowing water might change because of the bottom slab.
- The sharp corners of the box-shaped slabs make it unsuitable for vehicles running at high velocity.
- Box culvert is required for purposes which require artificial flooring.
- It can be used for rainwater disposal and drainage, hence it might not have used in dry seasons.