SAID T. GOMAA, MOHAMMED H. BALUCH, HAMDY H. ABDEL‐RAHMAN and AMMAR K. MOHAMMED
A finite element formulation for flexure of isotropic plates based on a recent refined theory is developed. The refined theory incorporates effects of transverse shear, transverse…
Abstract
A finite element formulation for flexure of isotropic plates based on a recent refined theory is developed. The refined theory incorporates effects of transverse shear, transverse normal stress and transverse normal strain. The Galerkin finite element method was used to develop the finite element equations for both plate bending and inplane problems. The performance of the proposed finite element model was evaluated by solving problems of uniformly loaded thick plates with different support conditions. The results of the present formulation are compared with Mindlin/Reissner and elasticity solutions.
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Y.N. Ziraba, M.H. Baluch, A.M. Sharif, G.J. Al—Sulaimani, A.K. Azad and I.A. Basunbul
This paper presents a finite element model for analysis of damaged RCbeams strengthened or repaired by externally bonding glass fibre reinforcedplastics (GFRP) on the tension side…
Abstract
This paper presents a finite element model for analysis of damaged RC beams strengthened or repaired by externally bonding glass fibre reinforced plastics (GFRP) on the tension side of the beams. The salient features include: (i) the introduction of a thin, six—noded element to simulate behaviour of the concrete/epoxy glue/GFRP interface and )ii( a scheme of loading a virgin RC beam to a prescribed displacement to simulate damage, unloading and then reloading the damaged RC beam fortified by an externally bonded GFRP plate. Results are presented for RC beams repaired by plates of varying thickness and a transmutation of failure mode is noted from classical flexure for the case of external reinforcement in the form of thin GFRP plates to a unique concrete cover rip off failure for thicker GFRP plates and not predicted by the ACI shear strength formula for diagonal tension failure of unplated RC beams of similar geometry.
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Hamdy H. Abdel‐Rahman, Mohammed H. Baluch and Ali I. Al‐Hejji
A new finite element model has been developed for the analysis of thick beams that incorporates the influence of transverse normal strain in addition to the effect of transverse…
Abstract
A new finite element model has been developed for the analysis of thick beams that incorporates the influence of transverse normal strain in addition to the effect of transverse shear strain. It has been shown that the inclusion of the normal strain effect into Timoshenko beam formulation, in the new model, results in the modification of the element force vector only, where a new term is added, while keeping the flexural and shear contributions to the element stiffness matrix unchanged. Comparisons between closed form solutions, Timoshenko beam results and the results of the new model for isotropic beams of depth to span ratio of up to 0.5, show that the new development reduces the errors with respect to exact solutions to almost a half at a very little extra expense.
M.S.A. ABBASI, M.H. BALUCH, A.K. AZAD and H.H. ABDEL‐RAHMAN
This paper presents the full range sensitivity study of various components of material model on the response of reinforced concrete slabs subjected to central patch loads using…
Abstract
This paper presents the full range sensitivity study of various components of material model on the response of reinforced concrete slabs subjected to central patch loads using non‐linear finite element analysis. A layered degenerate quadratic plate element with five degrees of freedom was employed. Smeared crack model was used with orthogonal cracking. The components considered in this work are: perfectly plastic models versus hardening models, role of crushing condition on collapse load, influence of dowel effect on punching capacity, parametric variation of tension stiffening parameter, parametric variation of degraded shear modulus and the role of yield criterion.
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A.M. Shazali, K. Rahman, M.H. El‐Boghdadi, S.F. Taher and M.H. Baluch
Focuses on a finite element computational model for the Timoshenko beam which is idealized as an elasto‐plastic‐damage medium governed by Lemaitre’s continuum damage mechanics…
Abstract
Focuses on a finite element computational model for the Timoshenko beam which is idealized as an elasto‐plastic‐damage medium governed by Lemaitre’s continuum damage mechanics (CDM) model for ductile fracture. Response under monotonically increasing loading does not show any deviation from elasto‐plastic simulation. However, a marked difference in the residual stress field is noted by virtue of the unloading phase, in which the CDM model allows for stiffness degradation in contrast to classical elasto‐plasticity which requires unloading at the (frozen) initial stiffness of the material.
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Khalid Abou El-Ftooh, Ahmed Atta, Ayman Ahmed Seleemah and Salah El-Din Fahmy Taher
Separately, nonlinear finite element analysis, artificial neural networks (ANNs) and continuous damage mechanics (CDM) attracted many investigators to model masonry infilled…
Abstract
Purpose
Separately, nonlinear finite element analysis, artificial neural networks (ANNs) and continuous damage mechanics (CDM) attracted many investigators to model masonry infilled frames. The purpose of this paper is to pursue four phases to develop a versatile model for partially and fully low-rise infilled RC frames using these tools.
Design/methodology/approach
The first phase included the study of the behavior of 1,620 low-rise infilled reinforced concrete frames using macro-scale nonlinear pushover finite element analysis. The approach helped to explore the effects of imposing different masonry infill distributions for one of the typical models of school buildings in Egypt. The outputs of this phase were used in the second phase for the development of an ANN model where input neurons included number of stories, continuity conditions, frame geometry, infill distribution and properties of RC sections. The third phase included the employment of the notions of CDM on the structural scale. Monitoring frames’ stiffness degradation allowed for damage variables identification. In the fourth phase, the simpler equivalent static lateral load (ESLL) for elastic analysis was employed in conjunction with ANN and CDM to obtain the capacity curves for partially and fully low-rise infilled RC frames.
Findings
The obtained capacity curves were compared with the nonlinear finite element results. The close agreement of all curves indicated how rigorous, yet simple, the suggested solution procedure is.
Social implications
The study is concerned with an important type of service buildings. These are the school buildings of Egypt.
Originality/value
The paper presents a combination of four phases that include FE analysis, ANNs, ESLL, and CDM to obtain the capacity curves for partially and fully low-rise infilled RC frames. Such a combination of approaches in tackling a practical problem related to service buildings is innovative and deserves research interest.
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Abdel‐Hakim A. Khalil, Tarek M. Fawzy, Salah El‐Din F. Taher and Galal A. Abdellah
In this paper, Isoparametric finite element formulations are derived for special elements for representing the steel‐concrete interface. Curved multi‐noded Isoparametric element…
Abstract
In this paper, Isoparametric finite element formulations are derived for special elements for representing the steel‐concrete interface. Curved multi‐noded Isoparametric element for reinforcing steel idealization is proposed. In addition, special thin Isoparametric element in a form of a sheath is suggested in order to model the bond‐slip characteristics. Special provisions are taken into account to avoid numerical difficulties. The proposed elements are incorporated in non‐linear finite element program DMGPLSTS and applied to the problem of tension stiffening of reinforced concrete members. The results are noted to reflect a softer overall response attributable to the slip effect.
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Temidayo Oluwasola Osunsanmi, Clinton Ohis Aigbavboa, Wellington Didibhuku Thwala and Ayodeji Emmanuel Oke
The prevalent practice of construction supply chain (CSC) in developing countries with a focus on Africa was presented in this chapter. Two African countries (South Africa and…
Abstract
The prevalent practice of construction supply chain (CSC) in developing countries with a focus on Africa was presented in this chapter. Two African countries (South Africa and Ghana) were selected due to the extensive literature on the CSC emanating from the countries. The impediment to the effective management of the CSC in the two African countries was also examined in this chapter. It was discovered that the vital inhibition to the performance of CSC in developing countries is the adoption of culture from developed countries without a proper model for ensuring its implementation in developing countries. Also, no model has incorporated the principles and technologies of the fourth industrial revolution (4IR) to manage the CSC. The failure to adopt the 4IR technologies like block chain, big data and the internet of things has prevented the proper application of CSC practices in developing countries. CSC practices like collaboration, integration, lean supply chain, information sharing, financial management and communication are the primary practice in developing countries. Finally, this chapter called for the development of a model for managing the CSC in developing countries in alignment with the principles of the 4IR.
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Kazim Ali, Muhammad Rizwan Yaseen, Muhammad Sohail Amjad Makhdum, Abdul Quddoos and Azeem Sardar
The main purpose of this study is to identify the socioeconomic determinants of dropout from primary schools and to give policy suggestions to address the issue.
Abstract
Purpose
The main purpose of this study is to identify the socioeconomic determinants of dropout from primary schools and to give policy suggestions to address the issue.
Design/methodology/approach
A total of 600 dropout and enrolled respondents were selected from 60 government primary schools of district Chiniot. School heads and parents of dropout children were taken as samples. The results were obtained by employing the Probit regression model.
Findings
Numbers of family members, age of the family head, exchange marriage and poverty status have positive relationship with dropout from primary schools. The findings revealed a higher rate of dropout among girls, which is a major cause of concern.
Practical implications
Education is regarded as a basic human right and a valuable human capital. It is included in Millennium Development Goals to achieve universal primary education and in Sustainable Development Goals as quality education. Underdeveloped countries are facing the problems of high dropout and lack of quality education, especially in Pakistan. These problems need to be addressed to keep pace with developed nations and to meet development goals.
Originality/value
It is recommended that government should create employment opportunities, family planning programs, legislature measures on exchange marriage and child labor. The involvement in co-curricular activities in learning and usage of audio-visual aids in the teaching process can improve the enrollment in the primary schools.
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Valentina A. Salomoni, Carmelo E. Majorana, Giuseppe M. Giannuzzi and Adio Miliozzi
The purpose of this paper is to describe an experience of R&D in the field of new technologies for solar energy exploitation within the Italian context. Concentrated solar power…
Abstract
Purpose
The purpose of this paper is to describe an experience of R&D in the field of new technologies for solar energy exploitation within the Italian context. Concentrated solar power systems operating in the field of medium temperatures are the main research objectives, directed towards the development of a new and low‐cost technology to concentrate the direct radiation and efficiently convert solar energy into high‐temperature heat.
Design/methodology/approach
A multi‐tank sensible‐heat storage system is proposed for storing thermal energy, with a two‐tanks molten salt system. In the present paper, the typology of a below‐grade cone shape storage is taken up, in combination with nitrate molten salts at 565°C maximum temperature, using an innovative high‐performance concrete for structures absolving functions of containment and foundation.
Findings
Concrete durability in terms of prolonged thermal loads is assessed. The interaction between the hot tank and the surrounding environment (ground) is considered. The developed FE model simulates the whole domain, and a fixed heat source of 100°C is assigned to the internal concrete surface. The development of the thermal and hygral fronts within the tank thickness are analysed and results discussed for long‐term scenarios.
Originality/value
Within the medium temperature field, an innovative approach is here presented for the conceptual design of liquid salts concrete storage systems. The adopted numerical model accounts for the strong coupling among moisture and heat transfer and the mechanical field. The basic mathematical model is a single fluid phase non‐linear diffusion one based on the theory by Bažant; appropriate thermodynamic and constitutive relationships are supplemented to enhance the approach and catch the effects of different fluid phases (liquid plus gas).