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.

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.

Redistribution of longitudinal moments in straight, continuous concrete slab – steel girder composite bridges

2006 ◽  
Vol 33 (4) ◽  
pp. 471-488 ◽  
Author(s):  
A Ghani Razaqpur ◽  
Afshin Esfandiari
Keyword(s):  
Finite Element ◽  
Concrete Slab ◽  
Limit State ◽  
Slab Thickness ◽  
Ultimate Limit State ◽  
Bridge Design ◽  
Moment Redistribution ◽  
Composite Bridges ◽  
Composite Bridge ◽  
Aashto Lrfd

The effect of loading and geometric parameters on the transverse and longitudinal redistribution of moments in continuous composite bridges, comprising a concrete slab on parallel steel girders, is investigated with the nonlinear finite element method. Fifty bridges are analyzed over their entire range of loading up to failure, and their moment redistribution factors are determined and compared with the relevant predictions of the Canadian Highway Bridge Design Code (CHBDC) and the AASHTO LRFD Bridge Design Specifications. The parameters studied included truck position along the bridge, number of loaded lanes, bridge width, number of girders, slab thickness, degree of composite action, and presence of diaphragms. The study reveals that among the preceding parameters only the number of loaded lanes and the bridge width significantly affect transverse redistribution of moments at ultimate limit state (ULS). However, most of the preceding parameters affect longitudinal redistribution at ULS. Finally, it is demonstrated that plastic analysis of composite multi-girder continuous bridges, treated as an equivalent beam, provides a reasonable estimate of their longitudinal moment redistribution capacity at ULS. It is demonstrated that the actual load-carrying capacity of a composite bridge may be more than 50% higher than that predicted by the CHBDC or AASHTO code. Such higher predicted capacity may obviate the need for retrofit in some cases.Key words: analysis, bridge, composite, concrete, distribution, finite element, inelastic, load, steel.

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.

scholarly journals Simplified method of applying loads to flat slab floor structural model

2018 ◽  
Vol 219 ◽  
pp. 03002
Author(s):  
Maciej Tomasz Solarczyk ◽  
Andrzej Ambroziak
Keyword(s):  
Reinforced Concrete ◽  
Structural Model ◽  
Concrete Slab ◽  
Limit State ◽  
Ultimate Limit State ◽  
Live Load ◽  
Element Mesh ◽  
Flat Slab ◽  
Chessboard Pattern ◽  
The Impact

The article analyses the impact of the live load position on the surface of a reinforced concrete flat slab floor of 32.0 m × 28.8 m. Four variants of a live load position are investigated: located on the entire concrete slab, set in a chessboard pattern, applied by bands and imposed separately in each of the slab panels. Conclusions are drawn upon differences in bending moments, the time of calculation and the size of output files. The problems in the interpretation of results are presented too. A procedure is presented to model the reinforced concrete structures in computational programs. The recommendations of the Eurocodes are presented regarding to load combinations in the Ultimate Limit State (ULS). Convergence analysis of the finite element mesh is carried out to verify the obtained results. The law status on the implementation of the Building Information Modelling (BIM) technology in Poland points out significant time savings in the application of this technology.

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 Assessment of the Effect of the Pre-cast Beams IG Axial Spacing on the Effort Bridge Span

2019 ◽  
Vol 1 (1) ◽  
pp. 281-288
Author(s):  
Roman Gąćkowski ◽  
Jacek Selejdak
Keyword(s):  
Reinforced Concrete ◽  
Positive Impact ◽  
Concrete Slab ◽  
Limit State ◽  
Concrete Bridges ◽  
Ultimate Limit State ◽  
Reinforced Concrete Slab ◽  
Bridge Span ◽  
Reinforced Concrete Bridges ◽  
Ultimate Limit

Abstract In designing of reinforced concrete bridges are often used pre-cast of pre-tensioned or post-tensioned prestressed members. In professional practice, when designing bridge span pre-cast of pre-tensioned prestressed beams IG type, different axial beams spacing’s are used and they are joined by a reinforced concrete slab. The paper presents a comparative analysis of an influence of the axial spacing of IG type beams in the cross-section of the bridge, on the bridge span effort, using standards PN-85/S-10042 and PN-EN 1992-2:2010. The optimal axial spacing of pre-cast IG type beams is presented, while maintaining the standard conditions of ULS (Ultimate Limit State). Such a solution has a positive impact on the costs of the entire project, significantly lowering the global investment cost.

Software for Design and Assessment of Rotationally Symmetrically Loaded Reinforced Concrete Slabs in the Shape of Circle or Ring

2015 ◽  
Vol 749 ◽  
pp. 368-372
Author(s):  
Jana Vaskova ◽  
Pavlina Matečková
Keyword(s):  
Reinforced Concrete ◽  
Limit State ◽  
Design Principles ◽  
Tangential Direction ◽  
Concrete Slabs ◽  
Ultimate Limit State ◽  
Serviceability Limit State ◽  
Reinforced Concrete Slabs ◽  
The Subject ◽  
Ultimate Limit

The subject of this paper is an universal software for reinforced concrete annular and circular slabs reinforced in the radial and tangential direction. Such slabs are used for roof and ceiling structures of buildings. The software can be used for design and assessment of rotationally symmetrically loaded annular and circular reinforced concrete slabs with arbitrary supports and span. Based on user's choice, the software proposes solutions to not only meet all the design principles, but especially ultimate limit state and serviceability limit state.

scholarly journals Effect of the Geometrical Constraints to the Wenner Four-Point Electrical Resistivity Test of Reinforced Concrete Slabs

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4622
Author(s):  
Kevin Paolo V. Robles ◽  
Jurng-Jae Yee ◽  
Seong-Hoon Kee
Keyword(s):  
Experimental Investigation ◽  
Electrical Resistivity ◽  
Reinforced Concrete ◽  
Concrete Slab ◽  
Plain Concrete ◽  
Electrode Spacing ◽  
Concrete Slabs ◽  
Reinforced Concrete Slabs ◽  
Spacing Ratio ◽  
Geometrical Constraints

The main objectives of this study are to evaluate the effect of geometrical constraints of plain concrete and reinforced concrete slabs on the Wenner four-point concrete electrical resistivity (ER) test through numerical and experimental investigation and to propose measurement recommendations for laboratory and field specimens. First, a series of numerical simulations was performed using a 3D finite element model to investigate the effects of geometrical constraints (the dimension of concrete slabs, the electrode spacing and configuration, and the distance of the electrode to the edges of concrete slabs) on ER measurements of concrete. Next, a reinforced concrete slab specimen (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)) was used for experimental investigation and validation of the numerical simulation results. Based on the analytical and experimental results, it is concluded that measured ER values of regularly shaped concrete elements are strongly dependent on the distance-to-spacing ratio of ER probes (i.e., distance of the electrode in ER probes to the edges and/or the bottom of the concrete slabs normalized by the electrode spacing). For the plain concrete, it is inferred that the thickness of the concrete member should be at least three times the electrode spacing. In addition, the distance should be more than twice the electrode spacing to make the edge effect almost negligible. It is observed that the findings from the plain concrete are also valid for the reinforced concrete. However, for the reinforced concrete, the ER values are also affected by the presence of reinforcing steel and saturation of concrete, which could cause disruptions in ER measurements

Sign in / Sign up

Export Citation Format

Share Document