Post-Installed Reinforcing Bar Guide

6.0 WHAT ’ S THE BACK STORY ?

shear force at the bar cutoff does not exceed 2 / 3 ϕV _{n}

, or b ) continuing reinforcement provides double the area required for flexure at the bar cutoff (# 11 and smaller ) and the factored shear force does not exceed 3 / 4 ϕV _{n}

, or c ) Stirrups or hoops meeting the requirements of e . g ., 9.7.3.5 ( c ) are provided along each terminated bar over a distance 3 / 4d from the cutoff point .

Section 9.7.3.8.2 requires that positive moment reinforcement in beams that are “ part of the primary lateral-load-resisting system ” be anchored to develop f _{y} in tension at the face of the support .

Section 9.9.4.5 requires that positive moment reinforcement in deep beams be anchored to develop f _{y} at simple supports unless the design is carried out using the strut and tie provisions of Appendix A .

Section 25.5.1.3 requires that bars spliced by noncontact lap splices in flexural members be spaced not more than the lesser of 1 / 5 the required splice length and 6 inches .

Table 25.5.2.1 provides requirements for Class A and Class B tension lap splices . Class A splices ( l _{d}

) are permitted where at least twice the required reinforcement is provided and 1 / 2 or less of the total reinforcement is spliced within the required lap length . Class B splices ( 1.3 l _{d}

) are permitted in all other cases .

Section 25.5.2.2 requires that bars of different size be spliced over a length not less than l _{d} of the larger bar or the tension lap splice length ( 1.3 l _{d} ) of the smaller bar .

Section 18.6.3.3 requires that hoops or spiral reinforcement is provided over the lap splice length of flexural reinforcement in special moment frames . Splices are not permitted within joints , within a distance of twice the member depth from the joint face , and “… where flexural yielding of the reinforcement is likely to occur as a results of lateral displacements beyond the linear range of behavior .”

Section 18.8.5.1 requires that the development length of # 3 through # 11 straight bars in tension in special moment frames be taken as shown in equation 9 :

Note : This equation , which is 2.5 times the value applicable to hooked bars , applies to low-lift construction and can therefore logically be extended to post-installed reinforcing .

Section 18.10.6.4 ( k ) permits horizontal reinforcement in the wall web to be anchored to develop f _{y} in tension within the confined core of the boundary element provided the required area of web reinforcement does not exceed the required area of the boundary element transverse reinforcement parallel to the web reinforcement .

Section 18.12.7.3 requires that all reinforcement “ used to resist collector forces , diaphragm shear , or flexural tension … be developed or spliced for f _{y} in tension .”

6.4 DEVELOPMENT AND SPLICING USING CSA A23.3-19 CHAPTER 12 PROVISIONS

CSA A23.3-19 Chapter 12 contains provisions for reinforcing bar development and splice lengths in non-seismic applications similar to those of ACI 318-19 . While not formally recognized in ICC-ES ESRs , Hilti HIT-RE 500 V3 and HIT-HY 200 V3 is commonly used with the provisions of CSA A23.3-19 based on the testing performed in accordance with ICC-ES AC308 . As with the design for ACI 318-19 Chapter 25 , design of postinstalled reinforcing bars with HIT-RE 500 V3 and HIT-HY 200 V3 may be performed equivalently to cast-in reinforcing bars using the applicable equations in CSA A23.3-19 , Chapter 12 . The basic expression for tension development length is provided in the equation as follows :

Post-installed reinforcing bars

Transverse reinforcement limits width of splitting cracks

A

CIP reinforcing bars

forces transferred directly to CIP reinforcing bars via bond

Section A-A f _{y} d l b d

= ( Eq . 9 ) ( 26 λ )

Section 18.8.5.4 requires that straight bars terminated at a joint pass through the confined core of a column or boundary element , and any portion of l _{d} not within the core be increased by a factor of 1.6 . Section 18.10.2.3 ( b ) stipulates that development length

l _{d} be increased by a factor of 1.25 . “… where yielding of longitudinal reinforcement is likely to occur as a result of lateral displacements …” in special structural walls and coupling beams .

Splicing of post-installed reinforcing bars Tension development length : CSA A23.3-19 12.2.2 EQ 12-1

f ^{=} ^{1} ^{.} ^{15} k _{1} k _{2} k _{3} k _{4} _{y}

A d ( d _{cs} + k _{b} _{tr)}

where the confinement term ( d _{cs} + K _{tr}

) shall not be taken greater than 2.5 times the bar diameter and the design value of l _{d} shall not be less than 300 mm per 12.2.1 .

25 2021