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

2020 ◽  
Vol 23 (8) ◽  
pp. 1614-1628 ◽  
Author(s):  
Mohamed H Mahmoud ◽  
Hamdy M Afefy ◽  
Ahmed T Baraghith ◽  
Amira B Elnagar
Keyword(s):  
Reinforced Concrete ◽  
Thin Layer ◽  
Strain Hardening ◽  
Human Life ◽  
Impact Resistance ◽  
Concrete Slabs ◽  
Cementitious Composites ◽  
Reinforced Concrete Slabs ◽  
Drop Weight ◽  
The Impact

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.

THE EFFECT OF IMPACT LOADS ON PRESTRESSED CONCRETE SLABS

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Youmn Al Rawi ◽  
Yehya Temsah ◽  
Hassan Ghanem ◽  
Ali Jahami ◽  
Mohamad Elani
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
Concrete Slabs ◽  
Shear Mode ◽  
Reinforced Concrete Slab ◽  
Finite Element Program ◽  
Reinforced Concrete Slabs ◽  
The Impact

Many research studies have been conducted on the effect of impact loading on structures, and design procedures were proposed for reinforced concrete (RC) slabs; however the availability of these studies and procedures are limited for prestressed slabs. The proposed research will examine, using numerical analysis, the impact of rock fall on prestressed concrete slabs with equivalent moment capacity reinforced concrete slabs. It is expected that prestressed concrete slabs will have different behavior to resist impact loading compared with traditional reinforced concrete slabs. The thickness of the prestressed concrete slab will be 25cm whereas that of the reinforced concrete slab will be 30cm. The impact loading consists of 500Kg drop weight. The drop height will be 10m, 15m and 20m.The structural analysis is performed using a Finite Element program "ABAQUS". A comparison will be done between both slab types in terms of failure mode, damage, and deflection. It has been found that both slabs failed in punching. However, the RC slab performed better than the prestressed concrete slab with respect to the value of the deflection at mid-span, while both showed punching shear mode of failure.

BEHAVIOR OF REINFORCED CONCRETE SLABS UNDER ACCIDENTAL IMPACTS

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Shamsoon Fareed
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
High Mass ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Reinforced Concrete Slabs ◽  
Numerical Predictions ◽  
Operational Life ◽  
The Impact

Loads resulting from activities such as rock fall, heavy drop weights (for e.g. equipment's, heavy machines during installation), missile and aircraft interaction with slabs may results in loading intensity which have higher magnitude as compared to static loading. Based on the velocity of the impacting object at the time of contact, these activities may result in impact loading. Therefore, slabs designed should provide resistance to these accidental loading during their entire operational life. In this study, a dynamic non-linear finite element analyses were conducted to investigate the behavior of the reinforced concrete slabs subjected to high-mass low-velocity impacts. For this purpose, initially an already published impact test results were used to validate the numerical predictions. Following validation, a study was conducted to investigate the influence of the impact velocity on the behavior of the reinforced concrete slab. Based on the numerical investigation, it was found that the velocity of the impacting object has a significant influence on the behavior exhibited by slab under impact loading. Furthermore, it was also found that the behavior of slab under impact is both local and global. Local behavior is associated with the damage caused at the contact area of the slab and the impactor, whereas global behavior refers to the overall deformation of the slab when stress waves move away from the impact zone and travel towards the supports.

scholarly journals Effect of Strengthening Methods on Two-Way Slab under Low-Velocity Impact Loading

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5603
Author(s):  
Sun-Jae Yoo ◽  
Tian-Feng Yuan ◽  
Se-Hee Hong ◽  
Young-Soo Yoon
Keyword(s):  
Reinforced Concrete ◽  
High Performance Concrete ◽  
Impact Load ◽  
Reaction Force ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Low Velocity Impact ◽  
Fiber Reinforced ◽  
Reinforced Concrete Slabs ◽  
The Impact

In this study, the performance of reinforced concrete slabs strengthened using four methods was investigated under impact loads transferred from the top side to bottom side. The top and bottom sides of test slabs were strengthened by no-slump high-strength, high-ductility concrete (NSHSDC), fiber-reinforced-polymer (FRP) sheet, and sprayed FRP, respectively. The test results indicated that the test specimens strengthened with FRP series showed a 4% increase in reaction force and a decrease in deflection by more than 20% compared to the non-strengthened specimens. However, the specimen enhanced by the NSHSDC jacket at both the top and bottom sides exhibited the highest reaction force and energy dissipation as well as the above measurements because it contains two types of fibers in the NSHSDC. In addition, the weight loss rate was improved by approximately 0.12% for the NSHSDC specimen, which was the lowest among the specimens when measuring the weight before and after the impact load. Therefore, a linear relationship between the top and bottom strengthening of the NSHSDC and the impact resistance was confirmed, concluding that the NSHSDC is effective for impact resistance when the top and bottom sides are strengthened. The results of the analysis of the existing research show that the NSHSDC is considered to have high impact resistance, even though it has lower resistance than the steel fiber reinforced concrete and ultra-high-performance-concrete, it can be expected to further studies on strengthening of NSHSDC.

scholarly journals Experimental research of the impact of upper reinforcement on the tension membrane action of narrow three-span reinforced concrete slabs

2020 ◽  
Vol 310 ◽  
pp. 00056
Author(s):  
Miroslaw Wieczorek
Keyword(s):  
Reinforced Concrete ◽  
Failure Mechanism ◽  
Experimental Research ◽  
Experimental Tests ◽  
Concrete Slabs ◽  
Membrane Action ◽  
Experimental Stand ◽  
Reinforced Concrete Slabs ◽  
Reinforced Steel ◽  
The Impact

The aim of the paper was to demonstrate the influence of reinforced steel parameters and quantity on the failure mechanism of four three-span models of reinforced concrete strips with the dimensions 7140×500×190 mm. Two models had only bottom reinforcement, while two were reinforced at the bottom and upper sides. The paper contains the description of the experimental stand and models along with the results of experimental tests which were compared with the results of the calculations based on traditional methods.

scholarly journals Researchon Impact Resistance of Fibre Reinforced Concrete

2019 ◽  
Vol 8 (6S4) ◽  
Keyword(s):  
Reinforced Concrete ◽  
Impact Test ◽  
Impact Resistance ◽  
Steel Fibers ◽  
Fibre Reinforced Concrete ◽  
Drop Weight ◽  
Weight Test ◽  
Drop Weight Test ◽  
The Impact

in this exam, an undertaking is needed to bear in mind the impact restriction of fiber bolstered concrete. on this exam, a easy, rational and reasonable drop weight test become finished on fiber invigorated cement as indicated with the resource of ACI board 544. Fibers containing steel, polypropylene, sisal have been used because the invigorating in four unmistakable quantity components, for instance, 0%,0.five%,1%,1.five%. The results validated that developing the quantity part of fiber prolonged the impact deterrent of sturdy version stood out from customary bond. The outcomes moreover shown that steel fibers are greater dominant at extending the impact test than severa strands.

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