Nonlinear Finite Element Analysis of Reinforced Concrete Slab Strengthened with Shear Bolts

This paper presents an implementation of a rational three-dimensional nonlinear finite element model for evaluating the behavior of reinforced concrete slabs strengthened with shear bolts under transverse load. The concrete was idealized by using eight-nodded brick elements. While both flexural reinforcement and the shear bolts were modeled as truss elements, a perfected bond between brick elements and truss elements was assumed. The nonlinear behavior of concrete in compression is simulated by an elasto-plastic work-hardening model, and in tension a suitable post-cracking model based on tension stiffening and shear retention models are employed. The steel was simulated using an elastic-full plastic model. The validity of the theoretical formulations and the program used was verified through comparison with available experimental data, and the agreement has proven to be good. A parametric study has been also carried out to investigate the influence of the shear bolts’ diameter and number of bolts’ rows around the column-slab connection, on the ductility and ultimate load capacity of slabs

Development of Finite Element Code for Analysis of Reinforced Concrete Slabs

A nonlinear finite element code has been developed to suite the analysis of normal and high strength concrete slabs. The computer program was built up using two computer languages, where the program interface part was coded in Visual-Basic language, while the main part was coded using FORTRAN language. A software called NLFEAS (Non-Linear Finite Element Analysis of Slabs) was developed to predicate and study the three dimensional response of reinforced concrete slabs of different grades, variables and boundary conditions under monotonically increasing loads. Using symmetry, a segment representing one quarter of the slab was considered in the analysis which was modeled using 20-node isoparametric brick elements and a 27-integration rule (3*3*3). Proper numerical material models for cracked concrete were incorporated in the analysis. The efficiency and accuracy of the developed code was verified through comparison with available test data, which showed good agreement. The effects of some finite element parameters such as mesh refinement and integral rule were also investigated

Swelling and Geotechnical Cartography of Saida Soils

The urban expansion and the increase in population led the urbanization to use the spaces called “at risk”.The integration and the treatment of ground’s movements constitute an important characteristic of the equilibrium established by nature. In the Saïda town (Algeria), many projects built on grounds with problems showed signs of degradations such as cracks in structures. These degradations led to the total destruction of the buildings. The principal causes of these disasters are: the expansive nature of soils and landslides, and the disaster phenomenon not considered in the first study of these constructions. The damage also touched road embankments, highways and foundations. In order to solve these problems, it was necessary to propose a geotechnical and risk map for the ZHUN EAST (ESSALAM city, Saïda), a city which includes several yards of the soil with problems, using the Geographical Information Systems (GIS/MapInfo). These tools enable us to express the perception of space and data processing, and consequently the cartography is carried out in an optimal way. These geotechnical and risk maps have a great part of importance in all levels of a study as information, working paper, alert, and especially is a tool for the decision-making aid, by expressing tendencies and orientations. They enabled us to give a field representing the active and potential movements with a hierarchy of risks to guide the developer and the engineer

Reliability and punching shear resistance of slabs in non linear domain

U radu se numerički ocjenjuje otpornost ploča na proboj te se prikazuje usporedba s predviđanjima utemeljenima na nekim propisima za projektiranje. Analizira se i interakcija glavnih parametara koji utječu na proboj i vrstu sloma ploča. Rezultati analize pouzdanosti prikazani su pomoću indeksa pouzdanosti za razne razine Pu/Pflex. Uz analizu pouzdanosti, provedena je i analiza osjetljivosti u smislu različitih razina opterećenja kako bi se na taj način istražio utjecaj osnovnih varijabli na rezultate.In this paper, the punching shear resistance of slabs is numerically evaluated and compared to predictions specified in some design codes. The interaction of major parameters that affect the punching shear behaviour and failure mode of slabs is also studied. Reliability analysis results are presented in terms of the reliability index for various levels of Pu/Pflex. In addition to the reliability analysis, the sensitivity analysis is carried out in terms of different load levels so as to study the effect of main variables on the results

Change and Persistence, Proceedings of the International Conference, Tunis, 12-13 November 2013

This publication is based on the proceedings of an international conference entitled ‘Arab Revolutions and Beyond: Change and Persistence’, which was held in the framework of a multilateral project called ‘Challenges and Transformations in the Wake of the Arab Spring’ (2012-2014). The project is funded by the DAAD (German Academic Exchange Service) and based upon the longstanding partnership between Cairo University in Egypt and Freie Universität Berlin in Germany, specifically between the EuroMed Study Program at the Faculty of Economics and Political Sciences (FEPS) and the Centre for Middle Eastern and North African Politics at Otto-Suhr-Institute, Department for Political and Social Sciences. Dieser Sammelband ist ein Ergebnis der internationalen Tunis-Konferenz "Arab Revolutions and Beyond: Change and Persistence", die im Rahmen des multinationalen DAAD-Projekts "Challenges and Transformations in the Wake of the Arab Spring" im November 2013 stattfand. Neben Kolleg_innen der Universität Kairo, mit der bereits eine langjährige Partnerschaft besteht, sind auch Nachwuchsforscher_innen aus Tunesien, Libyen, Jordanien und weiteren Arabischen Staaten beteiligt. Das Projekt stellt sich den Herausforderungen, welche sich durch die politischen und sozialen Umbrüche in der Region für die akademische Bildung, v.a. in den Sozialwissenschaften ergeben haben. Hieraus soll ein produktiver Dialog über theoretische, methodische und thematische Felder der Sozialwissenschaften eröffnet werden, um die Strukturen von Forschung und Lehre dauerhaft zu verbessern.This publication is based on the proceedings of an international conference entitled ‘Arab Revolutions and Beyond: Change and Persistence’, which was held in the framework of a multilateral project called ‘Challenges and Transformations in the Wake of the Arab Spring’ (2012-2014). The project is funded by the DAAD (German Academic Exchange Service) and based upon the longstanding partnership between Cairo University in Egypt and Freie Universität Berlin in Germany, specifically between the EuroMed Study Program at the Faculty of Economics and Political Sciences (FEPS) and the Centre for Middle Eastern and North African Politics at Otto-Suhr-Institute, Department for Political and Social Sciences. The project addresses the challenges of current political and social transformations and their ramifications for higher education and the social sciences in Egypt and the region. The overarching objective of the project is to enter a productive dialogue on theories, methodologies and topics in social science research among Arab and German researchers. At the same time, we aim to improve teaching and research structures in the social sciences in a sustainable and efficient way. This will build students’ and teachers’ capacities on both shores of the Mediterranean and at the same time strengthen institutional efforts to promote the role of social sciences in the current transformations

On the fatigue response of a bonded repaired aerospace composite using thermography

Lock-in thermography was employed to investigate the repair efficiency of a bonded repaired aerospace composite subjected to step-wise cycling mechanical loading. The studied component (substrate) was artificially damaged with a 5 mm circular notch and subsequently repaired with a tapered bonded patch. Critical and sub-critical damage of the repaired component was monitored via thermography during 5 Hz tension–tension fatigue. The examination of the acquired thermographs enabled the identification of the patch debonding propagation as well as the quantification of the stress magnification at the patch ends and the locus of the circular notch. It was found that fatigue mechanical loading yields both thermoelastic and hysterestic phenomena with the latter being more prominent prior to the failure of the studied repaired component