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Comparative Study by Simulation of Interlocking and Ordinary Building Blocks under Static Loads

Engineering（科研） 2020年第6期12卷 356-381页

作者： Joseph Bikoun Mousi edmond adjovi Mechanics Materials Structures and Productivity Laboratory (LM2SP) Doctoral Training Unit in Physics and Engineering Sciences University of Douala Douala Cameroon Laboratory of Energetics and Applied Mechanics (LEMA) of Polytechnic School of Abomey-Calavi University of Abomey-Calavi Abomey-Calavi Benin

In order to recommend the use of the masonry of chipboards with eviscerated bed joints and hollow vertical joints, we did a comparative study using simulation of the behavior of walls with traditional blocs and those of the new model of blocs. Thus, using Solidworks, we built up walls of 2.40 m length and 1.30m height following strictly the real constraints of elevation. Using finite elements method, the meshing, loading and the observation of the behavior are done through CosmosWorks. We can define a study used by Solidworks and Cosmos Works interface, and introduce parameters of walls;the meshing is then done (here we have volumic elements with three noses);then the big rigidity matrix is defined;the equations are also defined and solved and results are presented in numerical and graphical form. Since that form of results is not easy to analyse, we passed them to MATLAB in order to have usual curves more easily to analyse. The difficulty here is based on the conception of geometry of piece which must have same constraints and dimensions corresponding exactly to the real model. The other difficulty is to define parameters to use for a heterogeneous material like masonry. Once those difficulties are solved, the logical follows fully the steps of finite elements method until the solution in terms of noses repartition constraints, displacements and deformations. Then, we simulated the behavior on vertical static load, vertical static load and horizontal applied load and composed loads (vertical and horizontal) which are real conditions generally known in masonry walls. It has been shown that the new kind of masonry has a better behavior than the traditional one when loaded in its plan;in contrary, the behavior is less when loaded in the perpendicular plan.

关键词： Walls Chipboards Simulation Behavior Static Finite Elements

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Importance and Role of Biodiversity and Tropical Forests in the Cultural, Socio-Economic and Religious Life of African Black People： Case of Benin

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Journal of Environmental Science and Engineering(B) 2017年第6期6卷 312-322页

作者： adjovi edmond Codjo Amadji Togbe Armel Olodo Emmanuel Department of Civil Engineering Polytechnical School of Abomey-Calavi The University of Abomey-Calavi Abomey-Calavi 01-2009 Benin Department of Civil Engineering School of Bulding Science and Technology and Road The National University of SciencesTechnologies Engineering and Mathematics Abomey 243 Benin Department of Mechanical and Energy Engineering Polytechnical School of Abomey-Calavi The University of Abomey-CalaviAbomey-Calavi 01-2009 Benin

Biodiversity and tropical forests play a fundamental role in the life of the black people of Africa. In Benin, while some aspects of this role are well-documented, others are barely known. Moreover, these information remains so far very scattered through the literature which does not allow to have a global view on the contribution of biodiversity and forests to the life of people. In this work, it is presented the role of forests and biological diversity in the main vital areas of life of populations in south of Benin. The methodology used was based, with regard to the field, on bibliographical research, observation and/or field stakeholder survey. Investigations are more particularly focused on hardwood lumber uses and the species that are significantly used. The results highlight the uses that are made of vegetal elements of biological diversity and timber as forest products in south of Benin. The main areas explored are animist or traditional religion and traditional medicine, as well as socio-cultural and economic life. In this latter area, the most used timber species and their uses are identified; these include furniture, light carpentry, sculpture, formwork, canoe construction, drums and mortar making.

关键词： Biodiversity forest areas of life African populations wood

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Use of Additive Based on Non-Timber Forest Products for the Ecological Stabilization of Raw Earth:Case of the Parkia Biglobosa Nut and Vitellaria Paradoxa

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Journal of Renewable Materials 2023年第12期11卷 4143-4160页

作者： Bio Chéïssou Koto Tamou Jean-Michel Mechling Crespin Prudence Yabi Gildas EdjrossèF.Godonou edmond Codjo adjovi Mohamed Gibigaye AndréLecomte Nicolas Brosse L2EGC-Laboratory of Studies and Tests in Civil Engineering University of SciencesTechnologyEngineeringand MathematicsAbomeyBenin IJL-Jean Lamour Institute University of LorraineNancyFrance LEMA-Laboratory of Energetics and Applied Mechanics University of Abomey-CalaviAbomey-CalaviBenin LERMAB-Study and Research Laboratory on Wood Material University of LorraineNancyFrance

The housing sector today uses elaborate materials such as cement,iron,sand,often prohibitively expensive and whose production generates a strong environmental impact(scarcity of resources,transport,greenhouse gas greenhouse,etc.).In order to meet the challenges of sustainable development,earth construction is experiencing a resurgence of interest these *** its many advantages,raw earth material has drawbacks,in particular its low mechanical resistance and its loss of geometric characteristics in the face of water,which slow down its *** part of this study,the mechanical characteristics and durability of raw earth were improved by using residual water from the processing of Parkia Biglobosa(nere)and Vitellaria Paradoxa(shea)nuts in order to optimize its use for the construction of modern *** this end,the decoctions resulting from the artisanal transformation of the nut of the Parkia Biglobosa into African mustard and of the Vitellaria Paradoxa into shea butter were added to the raw earth according to volume proportions of 25%,50%,75%and 100%of the aqueous solution to obtain the projected ***,mechanical characterization and durability tests were carried out on the composites *** results revealed that the decoctions of Vitellaria Paradoxa and Parkia Biglobosa improve the compressive strength of the material by up to 90%and 260%,***,these decoctions improved the resistance to water penetration of the 100%additive composite by 1.5 times for Vitellaria Paradoxa and 5 times for Parkia *** study shows that it is possible to use decoctions as raw earth stabilizers to build modern,ecological buildings at lower energy ***,more in-depth studies on surface wettability and long-term durability are planned to better characterize the geomaterial.

关键词： Raw earth organic additive adobe Vitellaria Paradoxa Parkia Biglobosa durability

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Assessment of the Internal Instability for Granular Soils Subjected to Seepage

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Journal of Geoscience and Environment Protection 2016年第6期4卷 46-55页

作者： Marx Ferdinand Ahlinhan Marius Bocco Koube Codjo edmond adjovi Ecole des Sciences et Techniques du Batiment et de la Route (ESTBR) Université Polytechnique d’Abomey (UPA) Abomey Benin

The knowledge of the internal stability of granular soils is a key factor for the design of granular and filter for the geotechnical infrastructures such as dykes, barrages, weirs and roads embankment. To evaluate the internal instability of granular soils different criteria are generally used in the practice. However, the results of these criteria on the same soil may lead to different evaluations of the internal instability. In this paper the common criteria used for the internal instability have been presented and compared as far as possible. It was found that the most internal instability criteria define a limit value for the secant slope of the grain size distribution curve of the granular soils. Based on this finding an own criterion for the evaluation of the internal instability of granular soil has been developed and compared to the common criteria. A very good agreement between some criteria was found. Furthermore, a site specific assessment for the evaluation of the internal instability of granular soil has been proposed in order to get more confidence in this evaluation.

关键词： Internal Instability Granular Soils Seepage Dams Dykes Site Specific Assessment Instability Index

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Wastewater Management in Third World Cities: Case Study of Cotonou, Benin

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Journal of Environmental Protection 2014年第5期5卷 387-399页

作者： Sena Peace Hounkpe edmond Codjo adjovi Martin Crapper Esi Awuah Civil Engineering Department Université d’Abomey-Calavi Cotonou Benin Department of Civil Engineering Kwame Nkrumah University of Science and Technology Kumasi Ghana School of Engineering The University of Edinburgh Edinburgh UK

Poor wastewater management coupled with lack of sanitation facilities has aggravated the sanitation challenges in developing countries.?This study was aimed at providing information on the current state of sanitation in Cotonou City through surveys. The most common sanitation facilities in the city were septic tanks, latrines and soakaway pits. Mechanical desulging was mainly used (94%) for desludging latrines and septic tanks with a frequency of less than once a year for 73% of the houses;manual desludging was most common for soakaway pits. 84% of sullage generated is disposed without treatment. The only existing stabilization pond plant, managed by a private company SIBEAU, is overloaded;the effluent is poor (up to 2250mg/l BOD5) and does not meet any quality standards. 96% of survey respondents recognise that the sanitation situation in the city is not good;it has to be improved by providing an appropriate and sustainable sanitation management system.

关键词： Urban Sanitation Septic tanks Soakaway Pits Latrines Desludging Wastewater Treatment Developing World Cities

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Experimental Analysis of Hydraulic Conductivity for Saturated Granular Soils

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Geomaterials 2023年第3期13卷 71-90页

作者： Ahlinhan Marx Ferdinand Djenou B. Dorothée adjovi edmond Codjo Laboratory of Study and Test in Civil Engineering (L2EGC) National High School of Public Works (ENSTP) National University of Sciences Technologies Engineering and Mathematics (UNSTIM) Abomey Republic of Benin

Hydraulic conductivity is the ability of a porous media to transfer water through its pore matrix. That is a key parameter for the design and analysis of soil fluid associated structures and issues. This paper presents the test results of the vertical hydraulic conductivity kv carried out on one poorly graded sand and three gap graded gravely sand. It was found that the vertical hydraulic conductivity of saturated soil depends on the grain size distribution curve, on the initial relative density of the soil. Compilation of these current test results and other test results published, shows that the common approaches predict well to some extent the vertical hydraulic conductivity kv for the poorly graded sand materials and underestimate the kv values for gap graded gravely sand materials. Therefore, new approaches are developed for the prediction of the vertical hydraulic conductivity in saturated poorly graded sand and gap graded gravely sand. The derived results from the new approaches lie in the range of the recommended values by (EAU 2012) and (NAVFAC DM 7 1974).

关键词： Permeability Hydraulic Conductivity Tests Saturated Granular Soils Prediction Approaches

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Physical Characterization of Laterite for the Formulation of Structural Concrete

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Open Journal of Civil Engineering 2023年第3期13卷 411-426页

作者： Dekandji Thomas Ekpo Yemalin Daniel Agossou Judicial Agbelele edmond C. adjovi INSTI Lokossa National University of Sciences Technologies Engineering and Mathematics Abomey Benin L2EGC/ENSTP Materials and Structure Team National University of Sciences Technologies Engineering and Mathematics Abomey Benin

This study presents another approach to the use of laterite as a common construction material for the development of a new type of concrete. Laterites are found all over the world and are used in various ways in road construction as sub-base, base course or wear courses. Being a material consisting in the raw state of sand and gravel, the study addresses its use for the formulation of structural concrete. The physical characterization made it possible to identify three granular classes distributed as follows: 28.26% passing at 80 μm, 32.12% sand (0.08/4 mm) and 39.62% nodule (4/25) mm. The absolute density of the aggregates varies from 2.73 and 2.82 from the sand to the nodules. The absorption rate varies from 3.01% and 5.71% respectively for sand and nodules. The granular compactness of the different granular classes studied varies from 0.580 to 0.630. The formulation of the concrete was made by the method of absolute volumes by varying the W/C ratio from 0.4 to 0.7, N/S from 2.2 to 2.8 and that of the cement dosage from 350 to 450 kg/m3. The results obtained show that the density of the concrete formulated based on these aggregates of lateritic origin have a density which varies between 2000 and 2300 kg/m3. With a cement content of 400 kg/m3, a W/C ratio of 0.4 and N/S of 2.8, concrete based on lateritic aggregates offers better mechanical performance in compression of approximately 21.23 ± 1.24 MPa at 28 days. This strength class obtained allows laterite concrete to be used as structural concrete in the structure of civil engineering works.

关键词： Laterite Concrete Granular Compactness Mechanical Strength

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Influence of Salinity on Duckweed Growth and Duckweed Based Wastewater Treatment System

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Journal of Water Resource and Protection 2013年第10期5卷 993-999页

作者： Sena Peace Hounkpe Wendeou Martin Pepin Aina Martin Crapper edmond adjovi Daouda Mama Civil Engineering Department Université d’Abomey-Calavi Cotonou Benin Faculy of Science and Technology Université d’Abomey-Calavi Cotonou Benin School of Engineering The University of Edinburgh Edinburgh UK

The growth of duckweed (Spirodela polyrrhiza) was investigated in an outdoor batch system under 15 different conductivities ranging from 200 μS/cm to 3000 μS/cm with average 110 μmol/m2 daylight intensity. The growth was performed in an anaerobically treated domestic wastewater using an initial plants population of 50 fronds. Increase in Relative Growth Rate—RGR—(in terms of fresh weight and number of fronds) had a significant non-linear (polynomial) relationship with the conductivity. The maximum RGR related to fresh weight of 0.176 was observed at the conductiviity of 1200 μS/cm while the maximum RGR related to fronds number was 0.193 at the conductivity of 800 μS/cm. The optimum range for duckweeds growth was found to be between conductivities of 600 μS/cm and 1400 μS/cm. The maximal rates of removal of COD of 14.5 mg/day, of 0.65 mg/day, NTK of 15.68 mg/day, faecal coliforms of 100% and turbidity of 80.8% were observed in this range. The COD and PO42- removal rates were highly correlated to the growth rate, with the correlation factor of up to 0.783 and, then to the conductivity. The NTK reduction was positively related to the conductivity.

关键词： Duckweed S. polyrrhiza Growth Rate Conductivity Domestic Wastewater

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Experimental and Numerical Investigation of Stress Condition in Unstable Soil

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Open Journal of Civil Engineering 2016年第3期6卷 370-380页

作者： Marx Ferdinand Ahlinhan Emmanuel Kokou Wouya Yvette Kiki Tankpinou Marius Bocco Koube Codjo edmond adjovi School of Sciences and Technologies for Building and Road (ESTBR) Polytechnic University of Abomey (UPA) Abomey Benin Institute University of Technology Lokossa (IUT) University of Lokossa Lokossa Benin

In unstable soils, a special erosion process termed suffusion can occur under the effect of relatively low hydraulic gradient. The critical hydraulic gradient of an unstable soil is smaller than in stable soils, which is described by a reduction factor α. According to a theory of Skempton and Brogan (1994) [1], this reduction factor is related to the stress conditions in the soil. In an unstable soil, the average stresses acting in the fine portion are believed to be smaller than the average stresses in the coarse portion. It is assumed that the stress ratio and the reduction factor for the hydraulic gradient are almost equal. In order to prove this theory, laboratory tests and discrete element modelings are carried out. Models of stable and unstable soils are established, and the stresses inside the sample are analysed. It is found that indeed in unstable soils the coarse grains are subject to larger stresses. The stress ratios in stable soils are almost unity, whereas in unstable soils smaller stress ratios, which are dependent on the soil composition and on the relative density of the soil, are obtained. A comparison between the results of erosion tests and numerical modeling shows that the stress ratios and the reduction factors are strongly related, as assumed by Skempton and Brogan (1994) [1].

关键词： Unstable Soil Suffusion Hydraulic Gradient Stress Reduction Factor Laboratory Tests Discrete Element Modeling

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Influence of pH on Water Hyacinth Ponds Treating and Recycling Wastewater

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Journal of Water Resource and Protection 2022年第2期14卷 86-99页

作者： Sèna Peace Hounkpe Martin Crapper Albant Sagbo edmond adjovi Martin Pépin Aina Ecole Nationale Supérieure des Travaux Publics Université des Sciences Technologies Ingénierie et Mathématiques d’Abomey Abomey Benin Institute of Infrastructure and Environment School of Engineering University of Edinburgh Edinburgh UK Institut National de l’Eau Université d’Abomey-Calavi Abomey-Calavi Benin

This work has examined the effects of pH on the treatment efficiency and biomass production rate of water hyacinth ponds (WHP) treating domestic wastewater. Experiments were carried out outdoor in WHP, working under batch and subtropical environmental conditions, using pre-treated sewage with pH varying from 5 to 9. It was observed that the plants regulated the pH of the medium to within 6.4 to 7.1 during the treatment processes independently of influent wastewater pH ranges. This adjustment reduced the treatment performances and the biomass production in ponds, the alkaline conditions in ponds being less favorable to the activities of the plants. The optimal removal and biomass production was achieved with influent pH of 7 lying in the above interval. So the optimum influent pH for the growth of plants and the removal of nutrients and organic matters in WHP is within pH 6.4 to pH 7.1.

关键词： Sewage Treatment Biomass Production Water Hyacinth pH

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