Revenue House - architectural typology to be valorised

This research was carried out on the state of degradation of the historic core of Annaba city, Algeria. This degradation is caused by multiple factors, the most important of which is the absence of shared responsibility of public actors. The number of collapses multiplied which became a source for the creation of large office buildings with modernist tendencies, but without any architectural identity. The real estate park in downtown Annaba brings together urban entities according to various principles and logics of composition, structuring the urban image of the city of Annaba. The objective of this study is to build a complete catalogue summarizing the structures and fundamental characteristics of old buildings. Initially, this study defines all the notions linked to urban morphology and the typologies of housing. Secondly, an architectural study will be carried out on the “income house”, which represents the basic unit for the development of this historic nucleus. The typological analysis was applied to 44 buildings from the 19th and early 20th centuries located on the boulevard named “Revolution Square” in order to identify a set of common and specific criteria for the classification of “house income”.

Investigation of the mechanical and thermal characteristics of an eco-insulating material made of plaster and date palm fibers

The negative impact of the production and use of building materials on the environment has become evident, so in recent decades, to find more sustainable, eco-friendly, and low-cost materials, the last research tends to reconsider the use of natural fibers and traditional building materials. This paper aims to develop a bio-composite based on the southern Algerian region's local materials consisting mainly of plaster and waste from date palm trees. Many properties were examined experimentally through previous research of our team (physical, mechanical, and microstructure characteristics) [1, 2] to characterize these materials. Several samples of bio-composite of plaster configurations with short length (20mm) and eight-weight ratios (0.5% - 4%) of palm fibers were prepared for mechanical, thermal, and physical characterizations. In addition, tested all previous properties on the specimens after 28 days of curing in normal conditions. The results show a clear improvement in the bio-composites mechanical performance (an increase in the bending strength with achieving compressive strength) and their thermal properties, which have been well developed (density, thermal conductivity, and specific heat capacity). To enhance the resistance of palm fibers to chemical degradation in the plaster's alkaline environment and improve the adhesion between them, these fibers were treated with a NaOH solution of 1% concentration. The plaster's composites reinforced with date palm fibers can be qualified as eco-friendly and thermal insulation building materials.

Effects of different processes of tunneling on displacements soil using 3D Finite Element Method

The excavation process of tunnels induces stresses and deformation in the surrounding soil. The method of excavation is one of the major problems related to the safety of the operators and the ground stability during the construction of underground works. So, it is necessary to choose an ideal method to minimize the displacements and stresses induced by tunneling. The main aim of this study is to simulate numerically the effect of different processes of tunneling on ground displacements, the settlements at surface soil and the internal efforts induced in the lining tunnel; in order to select the best process of excavation, which gives us a less effects on displacements generated by tunneling, thus, ensuring the stability and the solidity of the underground constructions. In addition, this study allows us to control and to predict the diverse movements generated by tunneling (displacements, settlements, efforts internes) exclusively for the shallow tunnel nearby to the underground constructions in the urban site. This modeling will be done by employing five different processes for tunnel excavation using the NATM (New Austrian Tunneling Method) method. The first process, the modeling of the excavation tunnel, is done almost in the same way as in reality; the partial face excavation, with seven slices, made by the excavation. The second process, by partial face excavation, is divided into eleven slices, next, we used the partial face excavation by nine slices, and then in thirteen slices. Finally, the dig is made by full-face excavation. The paper contributes to the prediction of the response of the soil environment to tunnel excavation using the NATM method and to minimize the diverse movements generated by tunneling. The appropriately chosen methodology confirms that displacements and subsidence are strongly influenced by the tunneling method. The three-dimensional Finite Elements Method using Plaxis3D program has been applied in the numerical simulation. The study resulted in the recommendation of a process that minimizes the effect of excavation on subsidence and ground displacement for a particular Setiha tunnel.

Exploring the impact of balconies on cooling energy demand in an arid climate zone

This paper explores the impact of balconies on the energy demand required for cooling in the arid climate zone of the city of Adrar, in Algeria. For the purpose to assess several situations of the balconies, we have chosen a parametric method based on a campaign of thermal simulations. The open and eliminated balcony type were selected and characterized by four parameters: the balcony to room ratio, the orientation, the window type, and the balcony position. A set of 100 simulations was selected randomly based on the Monte-Carlo probability technique. The final sample was corrected based on Cook’s distance which gave 85 simulations as a final sample size. A generalized regression model was performed to identify the impact of each parameter. The accuracy of the model is above 97% and the sensitivity analysis shows that the most important factor is the balcony to room ratio which could reduce the energy demand up to 26% followed by the window type (24%), the orientation (8%) and the balcony position (5%). This conclusion stresses the idea of considering the balcony as a passive solution to reduce the cooling energy demand.

Experimental and numerical study of the behavior of a stone column subject to the loading effect

The realization of engineering structures in compressible sites, requires in-depth geotechnical reconnaissance, as well as a study of the mechanical behavior of the soil, in order to adapt suitable soil improvement solutions. This is the case with the Annaba viaduct in Algeria, where it was found during the site survey that the soil is poor and very compressible. The foundations in these soils eventually pose the problem of their low bearing capacity and significant settlement. This, therefore, leads to the choice of reinforcement techniques. Among the many methods of improving soils, we have selected the stone column technique. The object of our article is to study the behavior of these columns, in terms of settlement and, through the loading tests on real site, we have found out that the intermediate columns are stiffer and more confined than the bank columns and the percentage reduction in settlements of these two types is important. Then, this experimental study is validated by the Plaxis 2D software, where the configurations are studied to find the best model that approximates the real behavior of the reinforced soil.

Use of Biopolymers in the Stabilization of Clay Soils

The treatment and stabilization of soils make it possible to recycle materials on construction sites in preparation for the installation of a final covering or the construction of a road network. In road geotechnics, various materials such as lime, cement, and pozzolans were used as additions to stabilize clay soils. In recent years, bio-polymers and bacteria are of increasing interest to researchers in the field of stabilization and improvement of the physico-mechanical and chemical characteristics of clay soils. Currently, in place of traditional clay treatment techniques and to minimize environmental problems, natural fibrous waste is being used increasingly and spectacularly. Several studies on biotechnological engineering applications already exist, such as the use of vegetation, algae, bacteria, enzymes, and biopolymers. The northern Algerian region where the urban tissue does not stop expanding contains significant potential in terms of wheat straw, which represents a very present agricultural waste. So, there is a local interest in the sustainable development of several regions known to produce wheat. This study is interested in investigating the effect of wheat straw on the stabilization of swelling clay soil. In order to improve the physico-mechanical characteristics of clay soils, a series of laboratory tests (Atterberg limit, Proctor test, direct shear test, Oedometer test, and unconfident compressive strength test) were carried out on reconstituted clay soil with defined initial properties through numerous analyses (e.g., XRD and XRF) and then treated with different vegetable fiber content. The results indicate that there is an improvement in the compressibility characteristics of the treated soil, a remarkable decrease in the swelling index and the compressibility index respectively with increasing percentages of wheat straw.

An attempt to apply the kinematic method of rigid solids in the study of bearing capacity of shallow foundations

In the geotechnical engineering field, shallow foundations are frequently needed to ensure good fieldwork stability. They are also intended to permanently and uniformly transmit all load pressure on the seating floor. However, numerous mechanical constraints, such as bearing capacity of foundations, durability, stability, design of shallow foundations, lead, unfortunately, to a serious realization challenge. Finding an adequate solution presents the main goal and effort of both scholars and professionals. Indeed, the corresponding drawback is observed through the high number of reported damages that occurred in the structure of foundations and the punching failure. The failure mechanisms of shallow foundations, verified in full size or on scale models, show “sliding surfaces” and rigid (solid) blocks, which can be described with the kinematic method of rigid solids. The main objective of this study is the application of the kinematic method of rigid solids in the study of the stability of shallow foundations with respect to punching, the purpose of which is to determine the bearing capacity factors Nc, N γ, and the passive earth pressure coefficient Kp of foundations. In this context, two mechanical models have been proposed with 5 and 7 rigid solids, and a program developed via the MathCAD environment is applied to check the validity of the two previous models. The kinematic method of rigid solids gives results very close and comparable with that of Caquot/Kerisel for the factors of the bearing capacity and passive earth pressure coefficient - the ratio Kp - according to the five- and seven-solid model.

Asphalt mixture and its time delay of stress after strain at change of temperature and frequency

Materials in pavement construction are used due to their material properties. Asphalt mixtures, which are today most used during building pavement construction, have a significant place. Asphalt mixtures are classified as viscoelastic materials due to their material properties. This article focuses on the time delay of the stress behind the strain, which is a specific property for viscoelastic materials. It is particularly focused on one type of asphalt mixture, which is used in the binder course and in the upper base layer. The selected asphalt mixture was tested on a four-bending machine and the samples had a beam shape. The sample was tested at four temperatures and seven frequencies. In the discussion, the article focuses on the comparison of the time delay of the stress Δt behind the strain during the change of temperature and frequency. It is clear from the results that the selected asphalt mixture is significantly affected by the change in temperature as well as the change in frequency. The conclusion is devoted to a summary of the acquired knowledge and observation, which is focused on examples in practice.

Project Info Water

The main goal of Project Info Water is to raise awareness about water management and water resources in the Slovak republic. The target groups of the project are kindergarten students, primary school students, citizens of the affected area, and the government. The project contains four groups of activities – informal, media, online, and presentation activities. Informal activities include thematic brochures with a brief description of the topics Water of Eastern Slovakia, Household water, Flood, Flood protection, Water structures of Eastern Slovakia, Water in the landscape. The presentation activities include the description of webinars, the media, and social activities include print advertisement and access to social media fun pages.

Behaviour of Self-Compacting Concrete incorporating Natural Perlite used as Part of Cement and as Aggregates

Perlite, a natural glassy volcanic rock could be used as supplementary cementitious material to reduce environmental pollution and the consumption of precious natural resources in the concrete industries. The aim of this work is to assess natural perlite used as 50% aggregates substitution by volume (sand or gravel) and as 10%, 15%, 20% cement substitution in self-compacting concrete. Workability characteristics and mechanical properties were analysed. Results showed that replacing 50% of natural aggregates with 50% of perlite aggregates or substituting cement with 10% of perlite powder generated the best workability characteristics and improved compressive, flexural strength, and elastic modulus of concrete at 28 days. Moreover, the results were combined to develop correlations that prove to be good between mechanical properties of self-compacting. Using perlite as aggregates offers a new source of supply and saves natural aggregates. Also, perlite used as cement substitution helps to reduce PC consumption, cost, and CO2 emission.