Efficient strengthening of opened-joint for reinforced concrete broken slabs

Advances in Structural Engineering

Baraghith

et al. 2020

Impact loading could impair the entire structure or a part of it, thus making the human life at stake. In this study, to improve the impact resistance of reinforced concrete slabs under drop-weight loading, a thin layer of strain-hardening cementitious composites was added at either tension or compression side of the slab. The main parameter of this study was the three contact surface conditions, namely grinding, grinding plus steel dowels, and grinding plus epoxy adhesive, between the substrate slab and the strain-hardening cementitious composites layer. Therefore, 63 reinforced concrete slabs were prepared and tested under the effect of drop-weight falling from three different heights: 1, 1.5, and 2 m. In addition, for comparison purposes, additional seven slabs were tested under central incremental static loading until failure is presented. It was found that the strain-hardening cementitious composites–strengthening layer enhanced the impact and static response of the strengthened slabs when added at either tension or compression side. Besides, to achieve the outermost impact resistance showing ductile performance, it is better to provide a thin layer of the strain-hardening cementitious composites at the tension side of the slab connected to the substrate slab by epoxy resin applied on pre-prepared grinded surface.

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Impact and static behavior of strain-hardening cementitious composites–strengthened reinforced concrete slabs

Mahmoud

Advances in Structural Engineering

Baraghith

et al. 2020

“…2 were provided and extended outside concrete slabs in the tension side in order to hold the provided welded wire mesh in the UHP-SHCC material. The anchored welded wire mesh having a 4 mm bar diameter and a 100 × 100 spacing in both directions was provided in order to prevent the detachment between the substrate slab and the thin UHP-SHCC layer as confirmed by previous studies (Afefy et al, 2016; Afefy and Fawzy, 2013) as well as to enable the UHP-SHCC material to develop better crack distribution. Figure 3 shows details of both slabs of Group No.…”

Section: Experimental Work Programmentioning

confidence: 99%

“…This material provides higher compressive strength as well as tensile strength with strain hardening behavior. Previous studies approved the efficiency of such material in enhancing the overall structural performance of RC members when provided in either tension or compression side (Afefy et al, 2016;Afefy and Fawzy, 2013;Afefy and Mahmoud, 2014;Kunieda et al, 2009Kunieda et al, , 2010Li, 1993Li, , 2004.…”

Section: Introductionmentioning

confidence: 99%

Punching shear resistance of strengthened reinforced concrete interior slab–column connections using ultra-high-performance strain-hardening cementitious composite material

Advances in Structural Engineering

El-Tony

2019

The main target of this article is to find out the most applicable strengthening technique to change the brittle punching shear failure of slab–column connection to a ductile one. The considered strengthening technique uses the combined effect of the internal single-leg stirrups and a thin layer of ultra-high-performance strain hardening cementitious composite material provided in either tension or compression side. Thus, 12 slab specimens divided into four groups were prepared and configured. It was found that the slab provided with properly anchored single-leg stirrups with a cross-shaped thin layer of ultra-high-performance strain hardening cementitious composite material at the compression side proved the most efficient technique among all the considered configurations. This technique enabled the slab to sustain a punching load of about 2.38 times that of the control unstrengthened slab. In addition, it exhibited ductile failure showing strain hardening and softening plateaus. Finally, the experimental shear resistances of all the strengthened slabs were compared against the design resistances stipulated by different design standards such as the ECP 203-2007, ACI 318-14, DIN 1045-1, and EC2-2004 codes. It can be concluded that the failure characteristics stipulated by the DIN 1045-1 code showed the most rational results compared with those of the experimental findings.

“…This material is a new generation of fiber reinforced cementitious composites, which has high tensile ductility and durability characteristics along with strain-hardening plateau [1][2][3][4]. Because of the improved characteristics of the UHP-SHCC material in both compression and tension, it exhibited remarkable results in increasing and/or restoring the ultimate load carrying-capacity of reinforced concrete members when provided in either compression or tension side in the members [5][6][7][8][9]. The effect of small amount of reinforcement ratio on the UHP-SHCC tension members has been investigated in order to enhance the post cracking behavior [5].…”

Section: Introductionmentioning

confidence: 99%

Effect of Internal Reinforcement on the Tensile Characteristics of the UHP SHCC Material

Elnagar

Baraghith

International Journal of Advances in Structural and Geotechnica

et al. 2017

Ultra-High-Performance Strain-Hardening Cementitious Composites (UHP-SHCC) is one form of fiber reinforced composites, which has high compressive and tensile strengths along with high strain capacity in tension with strain hardening plateau. Obviously, proper selection of strengthening/retrofitting material plays an important role in restoring the lost capacity of the strengthened/retrofitted member. This paper investigated experimentally the effect of internal reinforcement in the UHP-SHCC specimens on the tensile strength as well as the cracking characteristics. Seven UHP-SHCC specimens with identical dimensions of 500 x 150 x 50 mm were tested under pure axial tension. Different configurations of the internal reinforcement were considered; namely, internal orthogonal mesh of clear spacing of 50 mm in both directions, or smooth bars of 6 mm diameter. For both configurations, different reinforcement ratios were considered. The experiential results showed that the internal mesh configuration enabled the specimen to develop better crack distribution along with higher tensile capacity compared to those of specimens having internal smooth bars configurations. In addition, increasing the internal reinforcement ratio resulted in increase the tensile strength of the UHP-SHCC as well as reduce the average crack spacing.