PSI - Issue 18

Muhammad Fawad et al. / Procedia Structural Integrity 18 (2019) 189–197 M.Fawad/ Structural Integrity Procedia 00 (2019) 000–000

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3.1.3. Load- Displacement Curve LD Curve show that at the maximum load, deflection value of 3.37mm is recorded. Curve is showing that the after maximum displacement the load value starts decreasing as the load bearing capacity of retrofitting material decreases.

Figure 3- LD Curve of Steel Plate Strengthening

3.1.4. Discussion on Results Steel plate strengthening has worked a lot for the subject bridge. The overall condition of bridge has been improved efficiently. These results show that the Displacement of bridge has been reduced from 19.9mm to 3.37mm, which is very less than the allowable deflection limit. Therefore, bridge is safe in this criterion. Overall cracked region has been reduced along the sidewalls and bottom plates. Cracked area of bridge has been reduced from 125.5 m² to 66.4 m², which is almost half the cracked area. Critical crack width has been reduced from 0.61mm to 0.237mm, which is less than the allowable crack width limit.

Figure 4-3D Model of Bridge- FRP Strengthening

3.2 Retrofitting Using FRP Strips In case of FRP, it is important to define that which kind of FRPs are needed for usage. It can be in the form of fabric sheets, fiber plates and CFRP bars. In this case, it will be more convenient to use the FRP strips (Like the steel plates). Among the available sizes, 3mm thick strips will be used having a width of 100mm. This size has been selected because it is easy to model in ATENA as discrete sized material creates some problems during modelling in ATENA. In this case we have to first design the reinforcement layout along the sidewalls and bottom plates of bridge. The number of strips are 17 strips along the sidewall and 46 along the bottom plate.After defining the material macro elements will be defined in the same way as defined in case of steel plate for FE modelling , the only difference is that