Analysis and deflections of reinforced concrete flat slabs

1998 ◽  
Vol 25 (3) ◽  
pp. 451-466 ◽  
Author(s):  
Alaa G Sherif ◽  
Walter H Dilger
Keyword(s):  
Reinforced Concrete ◽  
Design Method ◽  
Concrete Slab ◽  
The Finite Element Method ◽  
Bilinear Method ◽  
Flexural Members ◽  
Flat Slabs ◽  
Direct Design ◽  
Continuous Slab ◽  
Equivalent Frame

The results of a test on a full-scale 5 m continuous slab are used to study the methods of analysis and calculation of deflection of reinforced concrete flat slabs. The most commonly used methods for the analysis of flat slabs, namely the equivalent frame method, the prismatic member method, the direct design method, and the finite element method, are critically compared using the results of the slab tested. Based on the comparison with the unbalanced column moments in the test, improvements for the prismatic member method are suggested. For the deflection calculations of cracked reinforced concrete flexural members, three methods are investigated: the effective moment of inertia approach, the mean curvature approach, and the bilinear method given in the CEB manual for deflections. To calculate the deflections of flat slabs as column and field strip deflections, new coefficients for distributing the bending moments between the column and middle strips are proposed.Key words: analysis, deflection, flat concrete slab, test.

Microcomputer analysis of reinforced concrete slab systems

1993 ◽  
Vol 20 (4) ◽  
pp. 587-601 ◽  
Author(s):  
Pierre Léger ◽  
Patrick Paultre
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Structural Design ◽  
Concrete Slab ◽  
Three Dimensional ◽  
Structural Behaviour ◽  
Reinforced Concrete Slab ◽  
Element Analysis ◽  
Equivalent Frame ◽  
Frame Method

Microcomputer finite element analysis of reinforced concrete slab systems can now be routinely performed to produce realistic numerical simulation of three-dimensional structural behaviour. However, an efficient use of this approach requires an automated integration of design and analysis procedures. Guidelines for proper finite element modelling of slab systems are first presented along with simple post-processing algorithms to perform automatically the design or verifications from the analytical results. Numerical applications on simple slab systems subjected to uniform and concentrated loads are then used to illustrate the relative performance between finite element analyses and the equivalent frame method. Key words: microcomputer, reinforced concrete slab, finite element method, structural design.

scholarly journals DEVELOPMENT OF REINFORCED CONCRETE SLAB EMBEDDED WITH CAPSULE-SHAPED VOIDS : Structural experiment & design method(Structures)

2004 ◽  
Vol 10 (20) ◽  
pp. 119-124
Author(s):  
Yasuhiro ODA ◽  
Yasuyuki HOSOI ◽  
Hiroyuki TOMATSURI ◽  
Akio HOSHINO ◽  
Akira BANNO ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Design Method ◽  
Concrete Slab ◽  
Experiment Design ◽  
Reinforced Concrete Slab

scholarly journals A Design Method to Induce Ductile Failure of Flexural Strengthened One-Way Reinforced Concrete Slabs

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7647
Author(s):  
Huy Q. Nguyen ◽  
Tri N. M. Nguyen ◽  
Do Hyung Lee ◽  
Jung J. Kim
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
Design Method ◽  
Concrete Slab ◽  
Ductile Failure ◽  
Reinforced Concrete Slabs ◽  
Failure Loads ◽  
Ultimate Failure ◽  
Rc Slabs

Strengthening existing reinforced concrete (RC) slabs using externally bonded materials is increasingly popular due to its adaptability and versatility. Nevertheless, ductility reduction of the rehabilitated flexural members with these materials can lead to brittle shear failure. Therefore, a new approach for strengthening is necessary. This paper presents a methodology to induce ductile failure of flexural strengthened one-way RC slabs. Ultimate failure loads can be considered to develop the proposed design methodology. Different failure modes corresponding to ultimate failure loads for RC slabs are addressed. Flexural and shear failure regions of RC slabs can be established by considering the failure modes. The end span of the concrete slab is shown for a case study, and numerical examples are solved to prove the essentiality of this methodology.

scholarly journals Comparative Study Among Direct Design Method, Equivalent Frame Method and Finite Element Method for Analysis of Slabs

2018 ◽  
Vol 6 (2) ◽  
Author(s):  
Mereen Hassan Fahmi Rasheed ◽  
Bahman Omar Taha
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Design Method ◽  
Computer Software ◽  
Direct Design ◽  
The Face ◽  
Frame System ◽  
Equivalent Frame ◽  
Frame Method ◽  
Element Method

Beam-column frame system and flat plate slab system are analysed by semi-empirical, Direct Design method (DDM) and approximate elastic method, Equivalent Frame method (FEM) and the results of both methods are compared with computer software based on Finite Element method (FEM), taking into account the effect of changing the beam and column stiffness and the panel length ratio, for 3, 4, and 5 equal span frames and three non-equal spans. The moment coefficients with respect to the maximum clear span moment are determined by the three methods for negative end moments at the face of support and mid span positive moment. These coefficients are constant in DDM, while in EFM are changed with changing the column and beam sizes. The results of EFM is more accurate than DDM, on the bases of results of EFM, new moment coefficients are suggested to use instead of DDM moment coefficients. In case of EFM calculation aren’t satisfactory for hand calculations the FEM is used by applying available computer software.

scholarly journals The effect of cracks on the bearing capacity of reinforced concrete slabs

2019 ◽  
Vol 97 ◽  
pp. 03001
Author(s):  
Vladimir Agapov
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Strain State ◽  
Concrete Slab ◽  
Physical Nonlinearity ◽  
Concrete Slabs ◽  
The Finite Element Method ◽  
Reinforced Concrete Slab ◽  
Reinforced Concrete Slabs ◽  
Composite Fabrics

Cracks occur in reinforced concrete slabs for two reasons - due to increased operational loads and due to manufacturing and installation defects. When cracks are detected, the question arises about the residual bearing capacity of the slab and the need of its strengthening. To solve this problem by calculation, it is necessary to take into account physical nonlinearity. An algorithm for the calculation by the finite element method is proposed. The main feature of the algorithm is the use of multilayered finite elements, which allows modeling the cracks by specifying the corresponding material characteristics of those layers which the crack passes through. A method for determining the bearing capacity of a slab with cracks after its reinforcement with composite fabrics is also considered. An example of the study of the stress-strain state of a reinforced concrete slab with cracks by the proposed method is given. The implementation of the algorithm in the PRINS program is described and the possibility of using this program for solving practical problems is discussed.

scholarly journals Structural performance assessment of reinforced concrete flat slab-edge column connections under the effects of outward eccentricity

2015 ◽  
Vol 8 (2) ◽  
pp. 164-195
Author(s):  
N. G. B. Albuquerque ◽  
G. S. S. A. Melo
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Slab ◽  
Bending Moment ◽  
Structural Performance ◽  
Structural Behaviour ◽  
Reinforced Concrete Slab ◽  
Specific Test ◽  
Flat Slabs ◽  
Vertical Displacements

Although several advantages - either constructive or architectural - are assigned to flat slabs, the continuity between consecutive spans in multifloor buildings may turn slab-column connections into a critical region, due to the limited contact between both elements. When transferring moments caused by horizontal and/or vertical eccentric loads are present, these effects are even more pronounced on external panels. Specific studies on the effects of outward eccentricities are still rather scarce, although it is recognized that the codes, in general, are concerned with eventually meeting all potential cases, seeking to improve safety structural performance. Some current recommendations are based on considerable extrapolations, whose theory was originally developed for cases of asymmetric loading at internal connections and need to be consolidated with specific test data. Thus, to investigate the structural behaviour of slabs-edge columns connections, four specimens were tested, reproducing a 2,350 mm x 1,700 mm portion of a 180 mm thick reinforced concrete slab adjacent to a 300 mm x 300 mm cross section squared edge column, with a projection at the base for the imposition of eccentricities. The position of the support under the column has determined the eccentricity, defining in physical terms the interaction between bending moment and shear force, as follows: 300 mm (inward), centred (reference) and 300 mm and 400 mm (outward). Experimental results allowed to comparatively assess the performance of the specimens relating the strain measurements in steel and concrete, vertical displacements, rotations, failure mode and ultimate loads of the slabs. Results indicate that the influence of transferring moments on failure modes is much more pronounced than the shear action in the case of edge connections subjected to outward eccentricities.

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