Analytical method for derivation of stress block parameters for flexural design of FRP reinforced concrete members

This work derives stress block parameters for fibre-reinforced polymer (FRP) reinforced concrete (RC) members by applying the newly developed RC flexural theorems without doing structural tests. The equivalent rectangular stress block method is widely used for flexural design of RC members. Conventionally, stress block parameters are obtained from extensive flexural tests of RC members. Parameters of the stress block are closely related to material properties. Therefore, new stress block parameters are required when new materials, such as FRP, are used in construction. Structural testing is expensive, and test data is often insufficient for derivation of stress block parameters when a new material is applied in practice. The derived stress block parameters from this work and relevant RC flexural strength are compared with experimental results as well as those recommended by ACI 440.1R-15 and CSA-S806-12. More accurate results are obtained using the proposed parameters compared with those calculated from existing design codes. The method can also result in significant savings in FRP material due to more accurate calculation. The proposed approach facilitates more accurate yet convenient design for flexural strength of FRP-reinforced concrete members by engineers using the conventional stress block approach.