This guide provides recommendations on design provisions for the use of ASTM A1035/ASTM A1035M Type CS Grade 100 (690) deformed steel bars for reinforced concrete members. The recommendations address only those requirements of ACI 318-14 that limit efficient use of such steel bars. Other code requirements are not affected. Any other ACI 318 versions will be explicitly specified.
Although there are limiting ACI 318 requirements, ACI 318-14 Section 1.10 would allow the use of high-strength reinforcement. “Sponsors...shall have the right to present the data on which their design is based to the building official or to a board of examiners appointed by the building official.”
The International Building Code (IBC 2012) would allow the same under Section 104.11, “Alternative materials, design and methods of construction and equipment”. To approve an alternative material under this section, a building department would typically require an ICC Evaluation Service (ICC-ES) Evaluation Report, which would be based on an ICC-ES Acceptance Criteria (AC) document. An AC document (ICC-ES AC429) and an Evaluation Report (ICC-ES ESR-2107) exist, permitting the use of ASTM A1035/A1035M Grade 100 reinforcement.
This guide includes a discussion of the material characteristics of Grade 100 (690) ASTM A1035/A1035M (CS) deformed steel bars and recommends design criteria for beams, columns, slab, systems, walls, and footings for Seismic Design Category (SDC) A, B, or C, and for structural components not designated as part of the seismic-force-resisting system for SDC D, E, or F.
A structure assigned to SDC A, B, or C is required to be designed for all applicable gravity and environmental loads. In the case of SDC A structures, seismic forces are notional structural integrity forces. This guide addresses all design required for SDC A, B, and C structures.
Because the modulus of elasticity for ASTM A1035/A1035M (CS) is similar to that of carbon steel (ASTM A615/A615M) using higher specified minimum yield strength fy may result in higher steel stress at service load condition and potentially cause wider cracks and larger deflections, which may be objectionable if aesthetics and water-tightness are critical design requirements. Higher deflection can also contribute to serviceability issues. Also, with higher fy, the required development length will be longer.
Keywords: bar; design; guide; high-strength steel; structural.
Table of Contents
1.3—Historical perspective and background
1.4—Reinforcing steel grades availability
1.5—Introduction of ASTM A1035/A1035M Type CS Grade 100
CHAPTER 2—NOTATION AND DEFINITIONS
CHAPTER 3—MATERIAL PROPERTIES
3.2—Weights, dimensions, and deformations
3.3—Specified tensile properties
3.4—Measured tensile properties
3.5—Actual compressive properties
4.3—Tension- and compression-controlled limits
4.4—Strength reduction factor ϕ
4.5—Stress in steel due to flexure
4.6—Compression stress limit
4.11—Strength design for shear
5.2—Specified minimum yield strength for longitudinal reinforcement
5.3—Specified minimum yield strength for transverse reinforcement
CHAPTER 6—SLAB SYSTEMS
6.2—Shear design of one-way slabs
CHAPTER 8—FOOTINGS AND PILE CAPS
CHAPTER 9—MAT FOUNDATIONS
CHAPTER 10—OTHER DESIGN CONSIDERATIONS
10.1—Seismic design limitations
10.2—Development and lap splice length
10.3—Mechanically spliced bars and headed bars
10.4—Bending and welding of bars
10.5—Use of ASTM A1035/A1035M (CS) bars with ASTM A615/A615M bars
APPENDIX A—DESIGN EXAMPLES
APPENDIX B—FLEXURAL ANALYSIS USING NONLINEAR STRESS-STRAIN CURVE OF ASTM A1035/A1035M (CS) GRADE 100 (690) REINFORCEMENT
APPENDIX C—FLEXURAL BEHAVIOR OF BEAMS REINFORCED WITH ASTM A1035/A1035M BARS