IRC 112-2011-3

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  INDIAN HIGHWAYS, MAY 201531 Amendment No. 1/IRC:112-2011/January, 2015IRC:112-2011 “Code of Practice for Concrete RoadBridges” S. No.Clause No.& Page No.ForRead 1. 6.4.2.7(1)(Page 46)Creep of concrete depends, on the stress in the concrete, age at loading and duration of loading in addition to the factors listed in Clause 6.4.2.6(1). As long as the stress in concrete does not exceed 0.36 f  ck creep may be assumed to be proportional to the stress. Creep of concrete depends, on the stress in the concrete, age at loading and duration of loading in addition to the factors listed in Clause 6.4.2.6(1). As long as the stress in concrete does not exceed 0.36 f  cm ( t  0 ) creep may be assumed to be proportional to the stress. 2.6.4.2.7(2)(Page 47)The values given in Table 6.9 can be considered as final creep co-efficient for design for normal weight concrete, subject to condition that the compressive stress does not exceed 0.36  f   ck   at the age of loading and mean temperature of concrete is between 10ºC and 20ºC with seasonal variation between – 20ºC to 40ºC. For temperature greater than 40ºC the co- efficient given may be increased by 10 percent in absence of accurate data. In case the compressive stress exceeds 0.36 f  ck  , at loading, non-linear creep shall be considered. The values given in Table 6.9 can be considered as final creep co-efficient for design for normal weight concrete, subject to condition that the compressive stress does not exceed 0.36  f   cm  at the age of loading and mean temperature of concrete is between 10ºC and 20ºC with seasonal variation between – 20ºC to 40ºC. For temperature greater than 40ºC the co-efficient given may be increased by 10 percent in absence of accurate data. In case the compressive stress exceeds 0.36  f   cm ( t  0 ), at loading, non-linear creep shall be considered. 3.Table No. 11.1 Note below Table(Page 114) Note : Positional restraints are given for directions at right angles to the member  Notes :1.Positional restraints are given for directions at right angles to the member.2.Cases 1 to 5 shows superstructure held in position which means the deck is held in position at some location other than the pier under consideration (say typically either at another pier or at the abutment). 3. In case of any floating deck on elastomeric  bearings (simply supported or continuous), Case 7 will be applicable. 4. For a continuous deck fixed at any pier/abutment, Case 7 applies for the design of fixed pier/ abutment. For design of other piers in the longitudinal direction, Case 4 applies for piers with elastomeric bearings and Case 5 applies for  piers with free metallic bearings.4.11.3.2.2(1)(Page 115)Add at the end of the Clause.The effect of imperfection may be represented by an eccentricity in mm,limited to 50 mm l  o  is the height of pier in mm. AMENDMENT TO IRC:112-2011  32INDIAN HIGHWAYS, MAY 2015 S. No.Clause No.& Page No.ForRead 5.12.2.1(2)(Page 120)Where compressive stress in concrete under quasi-permanent loads is within 0.36  f   ck  , linear creep may be assumed. In case compressive stress exceeds 0.36  f   ck  , non-linear creep shall be considered, for which Annexure A-2 may be referred.Where compressive stress in concrete under quasi-permanent loads is within 0.36  f   cm ( t  0 ), linear creep may be assumed. In case compressive stress exceeds 0.36  f   cm ( t  0 ), non-linear creep shall be considered.For stress level in the range of 0.36  f   cm ( t  o ) < σ c  ≤ 0.48  f   cm ( t  o ) the non-linearity of creep may be taken into account using the following equation: ϕ σ   ( t  ,  t  o ) is the non-linear creep coefficient. ϕ  ( t  ,  t  o ) is the linear creep coefficient.k  σ   = is the strength ratio. 6.12.3.4(3)Under Eq. 12.9(Page 127)c is the clear cover to the longitudinal reinforcement.c is the clear cover to the longitudinal reinforcement. Wherever the clear cover exceeds 50 mm a value of 50 mm shall be used in the calculation. Errata No. 1/ IRC:112-2011/January, 2015IRC:112-2011 “Code of Practice for Concrete RoadBridges” S. No.Clause No.& Page No.ForRead 1.6.4.2.2(3)(Page 39) To avoid irreversible damage like local cracking (eg. due to early age prestressing) the achievement of early age strength shall be verified by testing. It is to be noted that the field testing results based on small number of samples are a measure of the mean value of early age strength and not of the characteristic value of early age. The values thus obtained should be reduced by 1.645 x (standard deviation for the grade of concrete). The value of the standard deviation to be used for early age is required to be established by testing at least 30 numbers of samples at site, unless it is know from  past experience. Refer Section 18 for details. To avoid irreversible damage like local cracking (eg. due to early age prestressing) the achievement of early age strength shall be verified by testing. Refer Section 18 for details.2.11.3.1(3)First line(Page 115)Stress – strain relationships for concrete given in Annexure (A2.7) and for steel given in Section 6 (Fig. 6.2 and 6.4) may be used.In so far as material non-linearity is concerned, stress – strain relationships for concrete given in Annexure A2-7 and for steel given in Section 6 (Fig. 6.2 and 6.4) may  be used.3.11.3.1(4)Last line(Page 115) In the absence of more refined models, creep may be taken into account by modifying all strain values in the concrete stress-strain diagram using effective E value as per Clause 6.4.2.5.4 (iii). In the absence of more refined models, creep may be taken into account by modifying all strain values in the concrete stress-strain diagram using effective E value as  per Clause 6.4.2.5(4) (iii).4.15.2.5.1(3)(d)Last line(Page 156)For splicing of bars in beams and columns the stirrups or links provided for other considerations can be taken into account to satisfy the requirement of (2) and its spacing shall not exceed 150 mm.For splicing of bars in beams and columns the stirrups or links provided for other considerations can be taken into account to satisfy the requirement of (b) and their spacing shall not exceed 150 mm.5.15.2.5.6.1 (10)Fig 15.6 (under RHS sketch) (Page 160)n 1  = 1 and n 2  = 2n 1  = 2 and n 2  = 2 AMENDMENT/ERRATA TO IRC:112-2011
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