Experimental and numerical investigation of one-way reinforced concrete slabs using various strengthening systems

Abstract

This paper presents different effective strengthening techniques to enhance the flexural strength of one-way reinforced concrete (RC) slabs. To assess the effectiveness of utilizing the suggested strengthening techniques, an experimental and numerical study was conducted. The experimental program included seven one-way RC slabs with dimensions of (2000 mm × 1000 mm x 150 mm). The first specimen was considered a control slab without providing any strengthening technique, and the remaining six specimens were strengthened with various systems. Ultra-High Performance Fiber Concrete (UHPFC) was used to strengthen the second specimen (S1-UHPFC), where a layer of UHPFC with a thickness of 50 mm was placed in the tension side of the slab within the specified slab depth. The third specimen (S2-HSC) is the same as the second specimen, but it is strengthened with High-Strength Concrete (HSC). The fourth specimen (S3-R.B) was strengthened from the bottom of the slab by bonding steel skewer bars with square cross sections (12 mm × 12 mm) by near-surface mount (NSM) technique. The fifth specimen (S4-C.B) is the same as the fourth specimen (S3-R.B) but the square skewer bars have been replaced by circular ones with a diameter of 12 mm. The sixth specimen (S5-S.P) was strengthened from the bottom of the slab by bonding stainless steel strips with a width of 50 mm and a thickness of 1 mm. The last specimen (S6-A.P) is similar to the sixth specimen (S5-S.P), but the stainless steel strips were replaced with aluminum ones. The results show that the failure loads of specimens S3-R.B and S4-C.B are greater than the control specimens S0-C.S by about 62 % and 41 %, respectively. In addition to specimen strengthening, using stainless steel strips or aluminum strips was less effective than the previous strengthening methods. However, this type is distinguished by its resistance to corrosion. To verify the outcomes of the experimental tests, a finite-element model using ABAQUS program was performed. Finally, An excellent agreement between the experimental and numerical results was obtained.