scholarly journals Serviceability limit state of two-way reinforced concrete slab strengthened with different techniques

2018 ◽  
Vol 162 ◽  
pp. 04001
Author(s):  
Eyad Sayhood ◽  
Ammar Ali ◽  
Zahraa Sharhan
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Limit State ◽  
Experimental Results ◽  
Bottom Surface ◽  
Reinforced Concrete Slab ◽  
Near Surface ◽  
Reinforced Concrete Slabs ◽  
Concrete Layer ◽  
Near Surface Mounted

The experimental results for service load of sixteen simply supported two way reinforced concrete slabs under the action of concentrated patch load were determined based on the amount of permissible deflections and the crack widths.All the slabs had the same overall dimensions and flexural steel reinforcement. Five types of strengthening were adopted. The first and second methods include applying either near surface mounted (NSM) or near reinforcement mounted (NRM) ferrocement layers. While the third method includes applying a concrete layer reinforced with welded wire fabric mesh of various diameters. The fourth and fifth methods include fixing CFRP rods and laminates, respectively, on the bottom surface of slabs. Strengthening techniques were applied on the bottom surface of fifteen slab specimens. In addition, a control slab specimen without any strengthening was used for the purpose of comparison. The calculated results for ultimate loads based on serviceability requirements (deflection and crack width according to both ACI and BS formulae) were lower than the experimental results.

Measuring the Deflection of Reinforced Concrete Slab

2015 ◽  
Vol 1106 ◽  
pp. 87-89
Author(s):  
Branislav Páleník ◽  
Anna Stará ◽  
Richard Kratochvíl ◽  
Miloš Zich
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Limit State ◽  
Concrete Slabs ◽  
Limiting Factor ◽  
Reinforced Concrete Slab ◽  
Precise Levelling ◽  
Reinforced Concrete Slabs ◽  
Concrete Ceiling

A significant limiting factor for the design of reinforced concrete ceiling slabs is the assessment of the limit state of deflections limit. There could be more methods of calculating deflections, but it is necessary to confront them with the reality on the construction. In this article the measurements of the deflection of reinforced concrete slabs are stated, which are then assumed to be compared with different calculation ways. For the measurement the slab was selected, which is located in a multifunctional building in Brno in Houbalova Street. The measurement was carried out by a precise levelling method.

scholarly journals Experimental and Theoretical Behavior of Reinforced Concrete Two Way Slabs Strengthened by Steel Fiber Ferrocement Layers at Tension Zone

2018 ◽  
Vol 26 (3) ◽  
pp. 199-211 ◽  
Author(s):  
Mazen D. Abdullah
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Concrete Slab ◽  
Experimental Results ◽  
Wire Mesh ◽  
Reinforced Concrete Slab ◽  
Concentrated Load ◽  
Simply Supported ◽  
Reinforced Concrete Slabs

An experimental and analytical  behavior of strengthened reinforced  concrete two way slabs  by steel fiber ferrocement layers ,this  study  included  testing 14  simply supported two way slabs, which include 1 control slab, 13 strengthened slabs. In the strengthened slabs the effect of  the ferrocement layers with; steel fiber content in the ferrocement mortar  of (0.25,0.5,0.75.1.1.25%), thickness of ferrocement layers, the compressive strength for ferrocement mortar and wire mesh layers number of ferrocement was investigated. The mid span deflection at ultimate load and cracks pattern  were discussed.  All the reinforced concrete slab specimens were designed of the same dimensions and reinforced identically to fail in flexure. Simply supported conditions for all slabs has bean tested under central concentrated load. The experimental results show that; the ultimate loads and mid span deflection of strengthened reinforced  concrete slabs were more effected by  using the steel fiber on the ferrocement mortar, increasing the thickness of ferrocement and the compressive strength of ferrocement. Three-dimensional nonlinear finite element analysis has been used to conduct the analytical investigation, ANSYS (Version 16.0) computer program was used in this study. The analytical result from modeling in ANSYS program exhibited a good agreement with experimental results.

Numerical Analysis of Anti-Impact Performances of the Reinforced Concrete Slab

2012 ◽  
Vol 249-250 ◽  
pp. 1063-1068
Author(s):  
Qian Ma ◽  
Dan Wu ◽  
Xu Dong Shi ◽  
Xiu Gen Jiang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Impact Resistance ◽  
Reinforced Concrete Slab ◽  
Reinforced Concrete Slabs ◽  
Steel Bar ◽  
Parameterized Modeling ◽  
Element Theory ◽  
Bar Diameter

The influence of the structure parameters on the anti-impact performances of the reinforced concrete slab is studied in the article. The reinforced concrete model is established by using ANSYS 13.0/LS-DYNA and nonlinear finite element theory and the parameterized modeling is achieved. The results show that the increase of the thickness of the slab and the steel bar diameter result in the enhancement of impact resistant capability of the slab; a appropriate quantity of reinforcement is significant; Increasing the concrete strength has a distinct impact on the slab’s impact resistance when using relatively low strength concrete. However the influence becomes weak after the concrete strength comes to C60 and higher. The fruits are useful to the designing of reinforced concrete slabs.

scholarly journals Reinforced Concrete Slab Optimization with Simulated Annealing

2019 ◽  
Vol 9 (15) ◽  
pp. 3161
Author(s):  
Flavio Stochino ◽  
Fernando Lopez Gayarre
Keyword(s):  
Simulated Annealing ◽  
Reinforced Concrete ◽  
Structural Optimization ◽  
Virtual Work ◽  
Concrete Slab ◽  
Limit State ◽  
Slab Thickness ◽  
Ultimate Limit State ◽  
Space Partitioning ◽  
Reinforced Concrete Slabs

Flat slabs have several advantages such as a reduced and simpler formwork, versatility, and easier space partitioning, thus making them an economical and efficient structural system. When producing structural components in series, every detail can lead to significant cost differences. In these cases, structural optimization is of paramount relevance. This paper reports on the structural optimization of reinforced concrete slabs, presenting the case of a rectangular slab with two clamped adjacent edges and two simply supported edges. Using the yield lines method and the principle of virtual work, a cost function can be formulated and optimized using simulated annealing (SA). Thus, the optimal distribution of reinforcing bars and slab thickness can be found considering the flexural ultimate limit state and market materials costs. The optimum result was defined by the orthotropic coefficient k = 8, anisotropic coefficient g = 1.4, and slab thickness H = 11.8 cm. A sensitivity analysis of the solution was developed considering different material costs.

Critical Review of Design Procedures for Reinforced Concrete Slabs as per IRC 112-2011

2019 ◽  
Vol 969 ◽  
pp. 349-354 ◽  
Author(s):  
J. Chithra ◽  
Praveen Nagarajan ◽  
A.S. Sajith ◽  
R.A. Roshan
Keyword(s):  
Reinforced Concrete ◽  
Critical Review ◽  
Concrete Slab ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Finite Element Software ◽  
Reinforced Concrete Slabs ◽  
Distributed Load ◽  
Uniformly Distributed Load ◽  
Sandwich Model

Nowadays finite element software is used for the design and analysis of reinforced concrete slabs. This paper intends to have a critical review based on a comparison study between the three design methods and to estimate the amount of reinforcement to be provided in each case. The three methods discussed are; the three-layer sandwich model (IRC 112-2011), Wood Armer method (EN1992-1-1:2004) and the conventional design method as per IS 456-2000. In the recently revised code for bridges IRC 112-2011, there is a recommendation to adopt three-layer sandwich model for the design of reinforced concrete slab. In this paper, a critical review of this method is done, and it is used for slabs subjected to uniformly distributed load. This method is illustrated by considering the design of rectangular slab subjected to uniformly distributed load. The results of this method are compared with the results obtained using Wood Armer method and using the moment coefficients suggested in IS 456-2000.

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 Finite Difference Energy Method for nonlinear numerical analysis of reinforced concrete slab using simplified isotropic damage model

2014 ◽  
Vol 7 (6) ◽  
pp. 940-964
Author(s):  
M. V. A. Lima ◽  
J. M. F. Lima ◽  
P. R. L. Lima
Keyword(s):  
Reinforced Concrete ◽  
Finite Difference ◽  
Energy Method ◽  
Virtual Work ◽  
Concrete Slab ◽  
Damage Model ◽  
Flexural Behavior ◽  
Structural Element ◽  
Reinforced Concrete Slab ◽  
Reinforced Concrete Slabs

This work presents a model to predict the flexural behavior of reinforced concrete slabs, combining the Mazars damage model for simulation of the loss of stiffness of the concrete during the cracking process and the Classical Theory of Laminates, to govern the bending of the structural element. A variational formulation based on the principle of virtual work was developed for the model, and then treated numerically according to the Finite Difference Energy Method, with the end result a program developed in Fortran. To validate the model thus proposed have been simulated with the program, some cases of slabs in flexure in the literature. The evaluation of the results obtained in this study demonstrated the capability of the model, in view of the good predictability of the behavior of slabs in flexure, sweeping the path of equilibrium to the rupture of the structural element. Besides the satisfactory prediction of the behavior observed as positive aspects of the model to its relative simplicity and reduced number of experimental parameters necessary for modeling.

scholarly journals Investigation on Structural Behavior of Bamboo Reinforced Concrete Slabs under Concentrated Load

2021 ◽  
Vol 50 (1) ◽  
pp. 227-238
Author(s):  
Yanuar Haryanto ◽  
Nanang Gunawan Wariyatno ◽  
Hsuan-Teh Hu ◽  
Ay Lie Han ◽  
Banu Ardi Hidayat
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Absorption Capacity ◽  
Concrete Slabs ◽  
Structural Behaviour ◽  
Reinforced Concrete Slab ◽  
Concentrated Load ◽  
Steel Reinforced Concrete ◽  
Reinforced Concrete Slabs ◽  
Cracking Pattern

Reinforced concrete is perhaps the most widely used building material in the world. However, the materials used for reinforcement of concrete i.e. steel is quite expensive and scarcely available in the developing world. As a result, bamboo is considered to be a cheaper replacement with high tensile strength. This research investigated the structural behaviour of bamboo-reinforced concrete slabs used for footplate foundation subjected to concentrated load. For this purpose, four different reinforced concrete slab panels were developed and analyzed. The influence of replacing steel with bamboo for the reinforcement of concrete slabs on their structural behaviour was assessed by determining the load-deflection characteristics, the ultimate load, the stiffness, the ductility, the cracking pattern, and the energy absorption capacity. The results showed that in comparison to steel reinforced concrete slabs, the strength of 82% can be acquired by the bamboo reinforced slabs. Furthermore, ductility demonstrated by the two types of specimens was almost equivalent i.e. up to 93%. Those indicated that the structural behaviour demonstrated by bamboo reinforced slabs is quite comparable to that of steel reinforced concrete slabs. Therefore, bamboo can prove to be a promising substitute for steel in concrete reinforcement. Future studies may further examine this opportunity.

scholarly journals Comparison of Predicted and Experimental Behaviour of RC Slabs Subjected to Blast using SDOF Analysis

2018 ◽  
Vol 68 (2) ◽  
pp. 138 ◽  
Author(s):  
F. B. Mendonca ◽  
G. Urgessa ◽  
K. Iha ◽  
R. J. Rocha ◽  
J.A.F.F. Rocco
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Experimental Program ◽  
Reinforced Concrete Slab ◽  
Peak Displacement ◽  
Blast Damage ◽  
Reinforced Concrete Slabs ◽  
Military Facilities ◽  
Rc Slabs ◽  
Sdof Analysis

<p>Explosions emanating from terrorist attacks or military weapons cause damage to civilian and military facilities. Understanding the mechanical behaviour of reinforced concrete structures subjected to blast is of paramount importance for minimizing the possible blast damage. A full-scale experimental program consisting of six reinforced concrete slabs with compressive strengths of 60 MPa, 50 MPa and 40 MPa, measuring 1.0 m × 1.0 m × 0.08 m, and subjected to 2.7 kg of non-confined plastic bonded explosive, was conducted in blast test area of Science and Technology Aerospace Department (Brazilian Air Force). This paper compares experimentally measured peak displacement values with theoretical values. Theoretical analysis was carried out using single degree of freedom (SDOF) models. The comparison showed that SDOF analysis worked very well in predicting the reinforced concrete slab peak displacement against blast effects. Qualitative analysis after the experiments showed that the blast wave shape generated by the cylindrical explosive was not uniformly distributed on the slabs for the standoff distance of 0.927 m∕kg1/3.<br /><br /></p>

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