The objective of this study is to use autoclaved aerated concrete (AAC) for infill walls in existing buildings that are unsafe for earthquakes to increase their stiffness. The study included two topics; the first topic introduced six models using AAC in buildings resistance to earthquakes and the effect of self-weight of the buildings comparing bare frame clay partition masonry model (1), bare frame AAC partition masonry model (2), reinforced concrete frames clay infill wall model ( 3), reinforcement concrete frames AAC infill wall model ( 4), reinforcement concrete frames AAC infill wall core model ( 5), reinforcement concrete frames AAC infill wall first and second floors model (6). ETABS software was used to investigate all frame models. Results of the study revealed that AAC infill wall decreases base moment, base shear and displacement. On the other hand, second topic presented five models of single reinforcement concrete frame under lateral loading, considering effect of anchored and unanchored AAC infill wall and clay infill wall. These models are bare frame model (a), RC frame with clay infill wall unanchored model (b), RC frame with AAC infill wall unanchored model (c), RC frame with clay infill wall with anchors model (d), RC frame with AAC infill wall with anchors model (e). Using finite element software (ANSYS WORKBENCH 18.2) failure load, displacement and ductility were presented for all five frames. The results showed that the 'RC frame with AAC infill wall with anchors' model gives the biggest failure load whereas displacement and ductility are the lowest.

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The development of composite sections is of great importance in structural design, with the aim of reducing weight and deflection while limiting the effect on the composite section’s strength and durability. This paper examines the computational analysis of composite sections where reinforced concrete was replaced with autoclaved aerated concrete (AAC) in the compression zone. The first principles of concrete combined with Hook’s law were adopted to find a flexure, shear, equivalent modulus of elasticity, effective moment of inertia, and deflection. The results are discussed and investigated using the finite element models developed by ANSYS WORKBENCH software. We found that the proposed analytical model can effectively provide a solution for the composite cross-section. The comparison between the theoretical calculation of the first cracking loads and the finite element percentage ranges from 89 to 110%. The ratio of the computational calculation of the modulus of elasticity to the finite element results ranged from 0.91 to 1.06. The comparison between the theoretical calculation of the effective moment of inertia to the finite element percentage ranged from 92% to 118%. The ratio of the computational calculation deflection to the finite element ranged from 0.87 to 1.15.

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The study of seepage through earth-fill dams is very important for the constructed dams to ensure that the control of seepage is sufficient for the safe and sustainable operation of the dam. It is also important in the design and construction of new dams to ensure that the seepage through and under the dam will be well controlled. Construction horizontal, inclined, trapezoidal or pipe filters one of the dam protection methods. Cut off also can be constructed to minimize seepage discharge directed to the downstream face of the dam. Seepage through an earth dam with internal cut off is experimentally studied in the laboratory of Irrigation Engineering and Hydraulics Department, Faculty of Engineering, Alexandria University, Egypt on a Hele-Shaw model. Also, using computer program SEEP/W (which is a sub-program of Geo-Studio). The experimental and numerical analyses of seepage through earth-fill dam with internal cut off is conducted. Results from solutions are compared with each other.