Slab strengthening

According to the design requirements, in the three-storey underground roof of the 4# garage, the 4-17 axis/4-G axis to the south of the 4-H axis post-pouring belt, the additional cover steel bar was originally designed as HRB400 25@200, and the site construction was HRB400 14@200. Therefore, it is necessary to adopt certain reinforcement measures to strengthen the floor structure. Consider sticking carbon fiber reinforced polymer(CFRP) sheet to reinforce.

Carbon fiber reinforced polymer(CFRP) sheet reinforcement for floor slab

According to the maximum transverse reinforcement area

As =25@200-14@200

   =490.9－153.9

   =337mm²

According to steel bar and carbon fiber technical index, the design strength of reinforcement is: fy=360N/mm²

Carbon fiber design strength: Ff=3400N/mm²

 Af×Ff =Asfy

  Af = fy×As / Ff

     = 360×337/3400

     = 35.69mm²

    B=35.69/0.167=213.72mm²  ＜300mm² 

After 15% fold shear, the cross-sectional area of carbon fiber is: 

150×2×0.85=255mm² ＞213.72mm² 

Therefore, in the south side of the post-cast strip of the floor, the double-layer 150 mm wide spacing 200 mm long carbon fiber reinforced polymer(CFRP) sheet is glued to meet the reinforcement requirements.