48 INDIAN HIGHWAYS, OCTOBER 2013

IRC

Amendment No. 1/ August, 2013/IRC:6-2010 to

IRC:6-2010“StandardSpecificationsandCodeofPracticeforRoadBridges, section II – loads and stresses”

(Fifth Revision)

Clause No. For Read

219.5.1 Fundamental time period of the bridge member is to be calculated by any rational method of analysis adopting the modulus of Elasticity of concrete as per IRC:21 and taking gross uncracked section for moment of inertia. The fundamental period of vibration can also be calculated by method given in Annex D.

Fundamental time period of the bridge member is to be calculated by any rational method of analysis adopting the modulus of Elasticity of concrete (Ecm) as per IRC:112 and considering moment of inertia of cracked section which can be taken as 0.75 times the moment of inertia of gross uncracked section, in the absence of rigorous calculation. The fundamental period of vibration can also be calculated by method given in Annex D.

219.9 (ii) under mandatory provisions

To improve the performance of bridges during earthquakes, the bridges in Seismic Zones IV and V may be specifically detailed for ductility for which IS:13920 or any other specialist literature may be referred to.

To improve the performance of bridges during earthquakes, the bridges in Seismic Zones III, IV and V may be specifically detailed for ductility for which IRC:112 shall be referred.

Amendment No. 2 /August, 2013/IRC:6-2010 to

IRC:6-2010“StandardSpecificationsandCodeofPracticeforRoadBridges, section II – loads and stresses”

(Fifth Revision)

Clause No. For Read

Fig. 13 of Clause

219.5

Period T (secs)

Note: For structural components like short and rigid abutments, the value of Sa/g shall be taken as 1. Also, the response reduction factor R shall be taken as 1.0 for seismic design of such structures.