SALIENT FEATURES OF IS:13920 - 1993. CODE OF PRACTICE FOR DUCTILE DETAILING OF RC STRUCTURES SUBJECTED TO SEISMIC FORCES. BEAM DESIGN: ( Actual program is available in Super Civil CD )
SR	DESCRIPTION
1	Ductile detailing is a must for structures in Zone IV & V. However it should also be followed in zone III, when  Importance factor is > 1.0  OR  Structure is > 5.0 Storey high  OR  the structure is industrial in nature.
2	Minimum longitudinal reinforcement on any face/section shall be : 0.24 * sqrt (fck)/fy
3	The factored axial stress shall not be > 0.1 fck, else the beam should be designed as column.
4	B/D > 0.30 preferably.
5	B should not be < 200 MM.
6	The maximum steel ratio should not be > 2.5 % per face.
7	Beam should not be a DEEP beam.
8	+ve reinforcement should not be < 50 % of -ve steel at that joint.
9	Minimum steel at any section face shall not be < 25 % of maximum -ve steel at any joint.
10	Re-distribution of support moments are not allowed for seismic moments at joints.
11	Development length {Ld} = Ld + 10 x Ø at end joints of column/beam.
12	Top & bottom reinforcements shall be continuous at column joints.
13	All links shall be closed type, having a 135° hook with a 10 Ø extension, but not less than 75 mm at each end.
14	The longitudinal bars shall be spliced, only if links are provided over the entire splice length at spacing not > 150 MM.
15	All splice shall have Ld in tension.
16	Lap splice shall not be at : Column Joints. 2 x d from column face. Within 0.25 x span.
17	Not > 50 % of bars shall be spliced at any section.
18	The Minimum link Ø shall be 6 MM for span < 5.0 M. Use 8 MM Ø links for span > 5.0 M.
19	The Links shall be designed for : Factored SF as per Analysis. SF due to formation of plastic hinges at both ends + gravity loads as per analysis.
20	Spacing of Links within 2 x d from supports shall be minimum of : d/4 8 x Ø of smallest longitudinal bar.
21	Spacing of links shall not be < 100 MM.
22	1st link shall start 50 mm away from support.
23	Spacing of links away from 2 x d from support shall not be > d÷ 2.
24	Link spacing shall not be > 300 MM. { As per IS-456-2000 }.
25	The top as well as bottom reinforcement shall atleast have 2 bars continuous throughout the whole member.
26	We have restricted the beam section to an Under-Reinforced Section so that they can undergo large rotation before failure. The contribution of concrete towards shear strength is neglected.