Design of SFRC Flexural Members
SFRC is a modified form of the concrete wherein the short and discrete steel fibers are dispersed in the concrete ingredients at the time of the mixing. The hardened product unlike a plain concrete possesses improved mechanical properties with an enhanced
- PDF / 858,280 Bytes
- 50 Pages / 439.37 x 666.142 pts Page_size
- 25 Downloads / 214 Views
Design of SFRC Flexural Members
SFRC is a modified form of concrete wherein short and discrete steel fibers are dispersed in the concrete ingredients at the time of mixing. The hardened product unlike a plain concrete possesses improved mechanical properties with an enhanced post-cracking tensile resistance and the toughness. This is happening because of the random distribution and orientation of the fibers in concrete caused at the time of mixing and its placement. When the alignment of the fibers coincides with the principal stress in a flexural member, the contribution of the fibers to the material strength is more pronounced than the case is otherwise. The fibers aligned along the direction of the principal stress in a member bridges the crack surfaces effectively and leads to a substantial increase in the ultimate tensile/flexural strength of SFRC member. The improved tensile-force carrying capacity of the concrete enables the designers to rely on the tension capacity of SFRC alone. Nevertheless, this improvement depends heavily on the pouring methods and the procedure used in the SFRC placement and its compaction in the moulds. Unlike the conventional reinforced concrete flexural members, the failure of an SFRC member takes place when the strain on its extreme tensile face exceeds the ultimate strain value, thereby leading to either fiber pullout or fiber fracture depending upon the fiber aspect ratio used in the concrete mix. However, it can be made to fail by crushing of the concrete similar to the conventionally reinforced concrete members, when the steel bars and the steel fibers are used together to reinforce it. The inclusion of conventional rebars in the tensile zone of SFRC member reduces the strain, drastically, on its tension face and results in reduction of the crack-widths significantly. The relatively fine crack-widths aided by the discontinuous nature of the short steel fibers in the SFRC lead to a substantial reduction in the probability of the corrosion initiation. As a result, the material offers a viable option to design and optimize conventional RC flexural sections with an enhanced ductility, durability and toughness (Singh 2015; de Renaud et al. 2012; Giuseppe and Maria 2008; RILEM 2001, 2002, 2003). The present chapter discusses the design concepts and a systematic procedure to proportion flexural members using SFRC as a construction material, along with the other methods prescribed by different guidelines and design codes for this purpose. © Springer Science+Business Media Singapore 2017 H. Singh, Steel Fiber Reinforced Concrete, Springer Transactions in Civil and Environmental Engineering, DOI 10.1007/978-981-10-2507-5_3
59
60
3.1
3 Design of SFRC Flexural Members
Structural Design—Concept
The basic aim of a structural design is to proportion and select various dimensions of the constituent members of the structural system and their other parameters, such as materials, shape, construction technique, etc. so that it should fulfil its intended purpose with an adequate safety, serviceability an
Data Loading...
