Abstract

Currently discovers have proven the use of new materials to improve the mechanical properties in reinforced concrete(RC)structures rather than the common ones used mostly in the past century such as steel rebar and light weight concrete.One of those materials that can fulfill these expectations is the use of Fiber-Reinforced Polymer(FRP)reinforcement as a prime material instead of steel reinforcement.

FRP reinforcement is commonly made from basalt,aramid,glass _or carbon.BENMOKRANE et al.[1-2]indicate some FRP reinforcement qualities like corrosion resistance,structure behavior and lightweight according to test results.The corrosion factor represents the main reason over steel reinforcement for choice selection.Hence,the FRP properties are being studied for the comprehension of its behavior in individual members as well as structural behavior.

Recently papers have been researching the FRP capacity under limit states design.FRP reinforced bars are checked for service limit state and ultimate limit state to control deflection,cracking and resistance.According to design,the ultimate limit is governed by the amount of reinforcement while the service limit is governed by the beam cross section and crack width respectively.International codes such as US codes[3-4]and Canadian codes[5]have similar approaches to identify service and ultimate limits state.

Due to its mechanical properties,FRP behaves as lineal elastic material up to its failure unlike steel reinforcement that yields.Also,because of its higher stress capacity(ffu)joined with a lower elasticity modulus(Ef)causes the service limit state often controls the design of FRP rather than the ultimate state limit.According to international codes formulas for FRP design,the ratio state limit[R,Eq.(1)]will have lower values due to current parameters.This implies an overdesign member or overstressing induced by high loads.

Meanwhile,for conventional RC beams the ratio is rather higher and usually the ultimate limit state governs its designs.This study intends to investigate the parameters to increase the efficiency on service limit state of FRP concrete beams to prevent overdesigning for ultimate limit state.

As a preliminary work,the study focuses on currently bibliographic resources(design codes,journey papers,reports)on the topic of service level on a first phase.Later on,it'll proceed to investigate the design parameters and establishes relationships between new and former variables from test specimens to develop prototype formulae for ratio improvement as a way to prevent overdesign member.