scholarly journals Assessment of reinforced concrete slab of historical structures by the yield-line method

2021 ◽  
Author(s):  
Rayan Mahrouseh ◽  
Zoltán Orbán

AbstractThe study demonstrates and evaluates an approach in the structural analysis phase when assessing reinforced concrete slabs.Due to different values of a parameter in the tests’ results, 10 models was crated for the first case study and 4 models for the second one.In order to compare the results in terms of the flexural bearing capacity, the slabs were analyzed by using elastic finite element analysis and yield-line analysis.Comparing the results shows that minor modification in the parameters associated with bearing capacity and the boundary conditions can affect the adequacy factor considerably, while the parameters those relate to boundary conditions affect the distribution of the yield lines.

The analysis of various regulatory methods for calculating reinforced concrete slabs for punching and comparing with experiment results is made. The tested sample, measuring equipment and test bench are described. Dimensions and materials for the production of the prototype were chosen on the basis of experience in the construction of girderless and capless regular monolithic reinforced concrete frames. The results of experimental studies of a fragment of a slab reinforced concrete structure in order to study the stress-strain state, when implementing the mechanism of punching, are presented. The results of observations obtained during the tests are presented. A comparison of the nature of operation of the tested fragment of the slab with the nature of operation of the full-fledged construction is given. A comparative analysis of the stress-strain state of the tested sample and the results of the calculation of the bearing capacity for punching according to various normative methods is performed. According to the results of the experiment, the main criteria determining the implementation of the punching mechanism are established, and a new method for calculating girderless floors is proposed on the basis of a fundamentally different approach in determining the bearing capacity.


2019 ◽  
Vol 97 ◽  
pp. 03001
Author(s):  
Vladimir Agapov

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.


2012 ◽  
Vol 249-250 ◽  
pp. 1063-1068
Author(s):  
Qian Ma ◽  
Dan Wu ◽  
Xu Dong Shi ◽  
Xiu Gen Jiang

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.


1993 ◽  
Vol 20 (4) ◽  
pp. 587-601 ◽  
Author(s):  
Pierre Léger ◽  
Patrick Paultre

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.


2019 ◽  
Vol 969 ◽  
pp. 349-354 ◽  
Author(s):  
J. Chithra ◽  
Praveen Nagarajan ◽  
A.S. Sajith ◽  
R.A. Roshan

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.


Author(s):  
Youmn Al Rawi ◽  
Yehya Temsah ◽  
Hassan Ghanem ◽  
Ali Jahami ◽  
Mohamad Elani

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.


Author(s):  
Shamsoon Fareed

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.


2014 ◽  
Vol 7 (6) ◽  
pp. 940-964
Author(s):  
M. V. A. Lima ◽  
J. M. F. Lima ◽  
P. R. L. Lima

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.


2021 ◽  
Vol 50 (1) ◽  
pp. 227-238
Author(s):  
Yanuar Haryanto ◽  
Nanang Gunawan Wariyatno ◽  
Hsuan-Teh Hu ◽  
Ay Lie Han ◽  
Banu Ardi Hidayat

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.


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