Design Criteria for bridge is a guideline for contractor’s designer to design the bridge structure with good engineering practice and in conformity with codal and departmental specifications. Separate criteria are devised for flyover and river/creek bridges. This is restricted use of certain type of structures as mentioned below :
(1) Structures sensitive to unequal settlement of foundations indeterminate structures like continuous beams, partial beams etc. resting on yielding type of foundations.
(2) Abutments resting on approach embankments.
(3) Stability of overall structure endangered due to failure of one or more span/spans.
(4) Superstructure with joints at the tip of long cantilevers with hinges or gap slabs.
(5) Structures with continuity only in deck slab, in transverse direction.
(6) Piers in the form of multiple columns with isolated/separate footings resting on yielding type strata.
(7) Spill through type of abutments for river bridges where spilled earth is subjected to stream velocity is more than 2 m/s and tied back returns exceeding 3m in length.
(8) Square ended piers for river bridges.
(9) 2-girder slab system for superstructure in severe exposure.
(10) Piles in deep scour and navigational zone.
Apart from this various limitations are given in the Designs Criteria in view of practices followed in the state/country.