The “Building Code Requirements for Structural Concrete” (“Code”) covers the materials, design, and construction of structural concrete used in buildings and where applicable in nonbuilding structures. The Code also covers the strength evaluation of existing concrete structures. Among the subjects covered are: contract documents; inspection; materials; durability requirements; concrete quality, mixing, and placing; formwork; embedded pipes; construction joints; reinforcement details; analysis and design; strength and serviceability; flexural and axial loads; shear and torsion; development and splices of reinforcement; slab systems; walls; footings; precast concrete; composite flexural members; prestressed concrete; shells and folded plate members; strength evaluation of existing structures; provisions for seismic design; structural plain concrete; strut-and-tie modeling in Appendix A; alternative design provisions in Appendix B; alternative load and strength reduction factors in Appendix C; and anchoring to concrete in Appendix D. The quality and testing of materials used in construction are covered by reference to the appropriate ASTM standard specifications. Welding of reinforcement is covered by reference to the appropriate American Welding Society (AWS) standard. Uses of the Code include adoption by reference in general building codes, and earlier editions have been widely used in this manner. The Code is written in a format that allows such reference without change to its language. Therefore, background details or suggestions for carrying out the requirements or intent of the Code portion cannot be included. The Commentary is provided for this purpose. Some of the considerations of the committee in developing the Code portion are discussed within the Commentary, with emphasis given to the explanation of new or revised provisions. Much of the research data referenced in preparing the Code is cited for the user desiring to study individual questions in greater detail. Other documents that provide suggestions for carrying out the requirements of the Code are also cited.

"building code requirements for structural concrete (aci 318-11) and commentary"

This article surveys the research and development of Engineered Cementitious Composites (ECC) over the last decade since its invention in the early 1990's. The importance of micromechanics in the materials design strategy is emphasized. Observations of unique characteristics of ECC based on a broad range of theoretical and experimental research are examined. The advantageous use of ECC in certain categories of structural, and repair and retrofit applications is reviewed. While reflecting on past advances, future challenges for continued development and deployment of ECC are noted. This article is based on a keynote address given at the International Workshop on Ductile Fiber Reinforced Cementitious Composites (DFRCC) - Applications and Evaluations, sponsored by the Japan Concrete Institute, and held in October 2002 at Takayama, Japan.

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On Engineered Cementitious Composites (ECC)

This paper presents the development of the PVA-ECC in the context of material design under the guidance of micromechanical tools. Specifically, this work illustrates how the fiber/matrix interface may be engineered to accommodate the requirements imposed by the micromechanical models, thus highlighting the importance of interface tailoring on the composite performance. This micromechanics-based material design approach is broadly applicable to achieving high-performance composites with low fiber content for cost-effective structural applications.

Interface tailoring for strain-hardening polyvinyl alcohol-engineered cementitious composite (PVA-ECC)

Seismic Rehabilitation of Existing Buildings

https://www.tpbin.com/Uploads/Subjects/0c9c42eb-ff6e-4ada-b126-dbb3146ed30e.pdf

Comparison of methods for arresting hydration of cement

This paper investigates the behavior of steel fiber-reinforced concrete (SFRC) beams in shear, as well as the possibility of using steel fibers as minimum shear reinforcement. In the study, 28 simply supported beams with a shear span-to-effective depth ratio of approximately 3.5 were subjected to a monotonically increased, concentrated load. The target concrete compressive strength for all of the beams was 41 MPa (6000 psi). The studied parameters included beam depth, fiber length, fiber aspect ratio, fiber strength, and fiber volume fraction. Three types of steel fibers were considered, all with hooks at their ends. The behavior of beams failing in shear prior to or after flexural yielding was also investigated by varying the longitudinal reinforcement ratio. Compared to reinforced concrete (RC) beams without stirrup reinforcement, the use of hooked steel fibers in a volume fraction greater than or equal to 0.75% led to an enhanced inclined cracking pattern and a substantial increase in shear strength.

Shear Behavior of Steel Fiber-Reinforced Concrete Beams without Stirrup Reinforcement

Current design provisions in the ACI Building Code for reinforced concrete (RC) coupling beams in earthquake-resistant structures require substantial reinforcement detailing to ensure a stable seismic behavior, leading toreinforcement congestion and construction difficulties. As a design alternative, the use of high-performance fiber-reinforced cementitious composites (HPFRCCs) in coupling beams with a simplified reinforcement detailing was experimentally investigated. To validate this alternative, four coupling beam specimens were tested, including an RC control specimen detailed as per the 1999 ACI Building Code. A precast construction process was proposed for the HPFRCC coupling beams in this study. This construction alternative would lead to significant savings in time and workmanship at the job site, and provide good material quality control. Results from large-scale tests demonstrated the superior damage tolerance and stiffness retention capacity of HPFRCC coupling beams. It was also observed that diagonal reinforcement is necessary to achieve large displacement capacity. However, the transverse reinforcement around the diagonal bars was successfully eliminated due to the confinement provided by the HPFRCC material.

/pdf/experimental-study-on-seismic-behavior-of-high-performance-3knqfrk8t8.pdf

Experimental Study on Seismic Behavior of High-Performance Fiber-Reinforced Cement Composite Coupling Beams

https://deepblue.lib.umich.edu/bitstream/handle/2027.42/31738/0000677.pdf;sequence=1

On the shear behavior of engineered cementitious composites

The inelastic cyclic response of hybrid connections consisting of RC columns and steel beams (RCS) is studied in this paper. Experimental results from the lateral load testing of nine exterior RCS connections are presented. The primary joint details investigated are two-part U-shaped stirrups passing through holes in the web of the steel beams, steel band plates or cover plates surrounding the joint region, steel fiber concrete or engineered cementitious composite material in the connection, and bearing bars attached to the steel beam. Experimental results indicate that RCS frames are suitable for use in high seismic risk zones. All of the specimens maintained their strength at large levels of story drift without significant loss of stiffness. A joint hoop volumetric ratio of 0.9% was found to be adequate for confinement in RCS joints. However, the amount of joint stirrups can be reduced or even eliminated if steel band plates, engineered cementitious composite material, or fiber reinforced concrete are u...

Seismic response of exterior RC column-to-steel beam connections

This paper describes the development of a theoretical model to predict the shear strength of reinforced concrete beams with and without shear reinforcement. It was assumed that the shear strength of concrete beams can be determined from the failure of the compression zone of a beam cross section. The shear strength of the compression zone was evaluated, considering the interaction between the shear strength and normal stresses developed by the flexural moment. The failure mechanism of the compression zone changes from a tension failure to a compression failure as the shear span-to-depth ratio decreases. The transition of the failure mechanism was properly addressed by considering the geometry of the beam and using material failure criteria of concrete. The proposed strength model can describe the failure mechanisms of both slender beams and deep beams with and without shear reinforcement. This model is verified and further discussed in a companion paper.

James K. Wight

Papers

Shear Behavior of Steel Fiber-Reinforced Concrete Beams without Stirrup Reinforcement

Experimental Study on Seismic Behavior of High-Performance Fiber-Reinforced Cement Composite Coupling Beams

On the shear behavior of engineered cementitious composites

Seismic response of exterior RC column-to-steel beam connections

Unified shear strength model for reinforced concrete beams - Part I: Development