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The optimal design of a twenty-five bar space truss commonly involves multiple loading conditions acting on 4 node elements in the linear elastic model. In this paper, we describe the behavior of the truss system with our experimental loading conditions on five node elements subject to minimum displacement and stresses that are used to formulate the constrained nonlinear optimization problem. Numerical computations are developed with the objective of mass minimization and the best structural design is selected by applying the interior point method with the guidance of Matlab Optimization Toolbox. Our numerical results show the optimal values of cross-sectional areas, material densities, and internal forces which satisfy the minimum weight design. These results provide the appropriate mass to the experimental data and allow substantial changes in size, shape, and topology.

All around the world, the Building Information Modeling (BIM) is transforming the architecture of engineering design and of construction industry. While it is in an early implementation stage in African Sub-saharan Countries, many construction regulators and project owners are beginning to enforce the BIM application from the project design stage to its commissioning. The aim of this research work is to provide an approach for designing industrial warehouses using BIM as it was done in the industrial zone of the Kribi Deep Sea port in Cameroon. The proposed methodology is presented in six steps: definition of BIM general requirements, design of the 3D BIM architectural model, sizing of wall and roof for specific requirements, design of the 3D BIM structural model, coordination of 3D BIM models and interference detection and creation of 4D BIM model. Results obtained from the application of BIM on the design of a warehouse, dedicated to preserve the natural and biological essence of cocoa and coffee products in a hostile marine environment, show that this methodology is easily appropriated and implemented by local design and construction engineers through available engineering software in the local market.

In the absence of the exact footing form of shallow foundations, we develop a procedure to determine the optimal footing form made up of four foothills from the knowledge of the inexact footing forms. The structural perturbations that are the major cause of the inexact forms are approximated in linear elastic model whose the solution is used to formulate the evolutionary structural optimization problem. To stabilize the solution, a serial of decisions is made to minimize structural perturbations in finite element modeling, initial volume and design constraints. By using the evolutionary structural optimization technique, we examine if the material of efficient and inefficient perturbations is needed or not on the points of inexact forms. Our analysis shows that the loading forces can be transferred to structural perturbations when they are efficient and used to reinforce the design material. This transfer can modify geometric elements of footing in finite element analysis and the optimal solution. The results of the numerical experiment provide the optimal footing form of shallow foundation, the sizes of associated foothills and the form of inefficient perturbations. This approach allows to redesign the structures from the inexact forms and detects the errors of dimensioning.

The selection of soils for construction of engineering structures is done on the basic of set number of criteria. In road construction, the criteria used are the value of the CBR index at 4 days imbibition. For earth dams and road embankments where materials should be compacted at their maximum dry density, we will adopt the criterion: the compaction characteristics at its optimum modified proctor. The determination of these criteria are very time consuming and can generate several delays which is inconsistent with the strategies of productivity of Publics Works companies. To reduce these delays, relations permitting us to predict their values from soil identification parameters should be developed. In this context, 1500 laboratory test results obtained from samples collected throughout the Cameroon territory were studied. Correlations which obtained were tested on around thirty results gave a prediction with error lower than 6.02%.