scholarly journals THE MECHANICS OF TENSILE MEMBRANE ACTION IN COMPOSITE SLABS AT HIGH TEMPERATURES

2016 ◽  
Author(s):  
Ali Alskeif ◽  
Ian W. Burgess ◽  
Shan-Shan Huang
Keyword(s):  
High Temperatures ◽  
Concrete Slabs ◽  
Steel Beams ◽  
Membrane Action ◽  
Yield Line ◽  
Flat Slabs ◽  
Plastic Yield ◽  
Reinforced Concrete Slabs ◽  
Load Carrying ◽  
Composite Slabs

<p>The mechanics of tensile membrane action of thinlightly-reinforced concrete slabs has been re-examined during the last two years.The re-examination is based on large-deflection plastic yield-line analysis, applied to flat slabs. As deflection increases beyond the optimum yield-line pattern, tensile membrane action is mobilized and further load carrying capacity is provided. This paper represents an extension of this re-examination to include composite slabs at high temperatures. As temperature increases, the unprotected downstand steel beams significantly lose capacity, allowing for further deflection until the overall capacity degrades to the applied load. Tensile membrane action then allows further increase of steel temperature until a maximum is reached.</p>

Experimental Behavior of One-Way Concrete Slabs at Large Displacements

2011 ◽  
Vol 105-107 ◽  
pp. 1035-1039
Author(s):  
Da Shan Zhang ◽  
Yu Li Dong
Keyword(s):  
Vertical Displacement ◽  
Concrete Slabs ◽  
Large Displacements ◽  
Membrane Action ◽  
Yield Line Theory ◽  
Reinforced Concrete Slabs ◽  
Load Carrying ◽  
Line Theory ◽  
Support Conditions ◽  
Displacement Transducers

This paper presents the tensile membrane action on one-way reinforced concrete slabs, and two full-scale specimens with one edge clamped and one edge simply supported were tested at large displacements. The details of the two tests including support conditions, arrangement of reinforcements and layout of displacement transducers are described. The test results show that the load-carrying capacity of the two slabs is significantly improved due to the tensile membrane action, about 26.6% more than the predicted value using the well-established yield-line theory. Until maximum vertical displacement reached 1/15 of the span-length, the slab did not fail and carried the load steadily.

Fire performance of reinforced concrete slabs: a numerical analysis

2021 ◽  
Author(s):  
Andreia Romero Fanton ◽  
Luiz Carlos de Almeida ◽  
Leandro Mouta Trautwein
Keyword(s):  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Finite Element Modelling ◽  
Concrete Slabs ◽  
Fire Performance ◽  
Membrane Action ◽  
Numerical Studies ◽  
Reinforced Concrete Slabs ◽  
Thermomechanical Behaviour ◽  
Load Carrying

<p>The emergence of tensile membrane action as a key load-carrying mechanism has increased experimental and numerical studies on the fire performance of concrete slabs since 2000, however, the different behaviour due to aggregate type is less studied in slabs numerical analysis. This paper presents a numerical analysis of the thermomechanical behaviour of reinforced concrete slabs exposed to fire, using Finite Element Modelling in ATENA and GiD. Results were validated against experimental data from the literature subjecting slabs to ISO834 and hydrocarbon time- temperature curves. 3 calibration steps were done to combine mechanical and thermal behaviours. A parametric analysis was carried out with calcareous and siliceous aggregates to provide information for safer slab design and consequent fewer accidents related to fire situation. The choice of aggregate type must always be considered in design.</p>

Numerical Limit Analysis of Slab Bridges with Construction Joints

2018 ◽  
Author(s):  
Thomas Westergaard Jensen ◽  
Linh Cao Hoang
Keyword(s):  
Carrying Capacity ◽  
Limit Analysis ◽  
Concrete Slabs ◽  
Load Carrying Capacity ◽  
Layer Model ◽  
Yield Criteria ◽  
Reinforced Concrete Slabs ◽  
Load Carrying ◽  
Construction Joints

The conic yield criteria for reinforced concrete slabs in bending are often used when evaluating the load‐carrying capacity of slab bridges. In the last decades, the yield criteria combined with numerical limit analysis have shown to be efficient methods to determine the load carrying capacity of slabs. However, the yield criteria overestimate the torsion capacity of slabs with high reinforcement ratios and it cannot handle slabs with construction joints. In this paper, numerical limit analysis with the conic yield criteria are compared with yield criteria based on an optimized layer model. The analysis show an increasing overestimation of the load carrying capacity for increasing reinforcement degrees. Furthermore, yield criteria, which combine the conic yield criteria with an extra linear criterion due to friction, are presented for slab bridges with construction joints. The yield criteria for slabs with construction joints are used, in combination with limit analysis, to evaluate a bridge constructed of pre‐cast overturned T‐beams and in‐situ concrete. The analysis show that the load carrying capacity is overestimated, when the construction joints are not considered in the yield criteria.

Load-Carrying Capacities of Fully Clamped RC Slab Accompanying Compressive-Tensile Membrane Actions: A Theoretical Approach

2020 ◽  
Vol 20 (08) ◽  
pp. 2050094
Author(s):  
Wanxiang Chen ◽  
Lisheng Luo ◽  
Zhikun Guo ◽  
Yingjie Wang
Keyword(s):  
Bearing Capacity ◽  
Carrying Capacity ◽  
Flexural Rigidity ◽  
Load Carrying Capacity ◽  
Membrane Action ◽  
Yield Line ◽  
Load Carrying ◽  
Membrane Effects ◽  
Rc Slab ◽  
Rc Slabs

Fully clamped reinforced concrete (RC) slab is a common structural component possessing better load-carrying capacity over simply supported slab. Currently, typical yield line theory is a popular approach to estimate the bearing capacity of fully clamped RC slab, although it would greatly underestimate the actual ultimate resistance. This paper is devoted to enriching the knowledge of membrane action and its contribution to the load-carrying capacity of the clamped slab. The resistance trajectory of fully clamped RC slab from loading to failure undergoes three phases: the ascending branch raised by outward movement prevention, the descending branch due to crushed concrete and the re-ascending branch caused by reinforcement strain. Applied load–deflection curves of RC slab accompanying compressive-membrane actions are achieved according to the bending theory of normal cross-section. The reserve capacities accompanying tensile-membrane actions in the condition of large deformations are further derived. The whole load–deflection curves that considered compressive-tensile membrane effects are finally presented, where the mid-span displacements are revised by the deflection equations and the softening coefficient of flexural rigidity. It is indicated that the load–deflection relationships of fully clamped RC slabs can be reasonably depicted by taking compressive-tensile membrane effects into account, which are fairly different from yield line approaches. Comparative analysis shows that analytical results are in good agreement with experimental data reported by Park et al. and illustrates that the proposed model is capable of predicting the bearing capacity of fully clamped RC slab with very good accuracy.

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