The construction costs of hospital buildings are relatively high due to the need to fulfill their complex functions and avoid mishaps. In this context, this study aims to minimize the total construction costs of hospitals while still satisfying the special architectural, practical, and structural requirements specified by design codes. To this end, 48 design alternatives with two floor systems (flat slabs with and without drop panels), three column spacings, and eight concrete grades were optimized using genetic algorithms provided by Palisade Evolver. The objective function included the materials and labor costs per square meter of the floor plan. The decision variables involved the concrete dimensions and steel bars of floors and columns. The hospital buildings were subjected to gravity, earthquake, and wind loads to thoroughly examine the realistic loading conditions. The design was performed in accordance with the Egyptian code for the design and construction of concrete structures and the Egyptian guidelines for hospitals and healthcare facilities. The results revealed that using low-strength concrete, and flat slabs without drop panels could achieve the best design. The slab thickness had a governing impact on the total cost of both floor systems.
Collapsible soils may experience sudden and excessive settlement when inundated. The use of pile foundations that penetrate the collapsible soil layer to reach a firm stratum is widely used in practice. However, when the ground is inundated, large and sudden settlement of the surrounding soil may take place, causing negative skin friction on the pile’s shaft, which may lead to catastrophic failure. In the literature, research dealing with negative skin friction for piles in collapsible soil is lagging due to the complexity of modeling collapsible soil analytically. Alternatively, results of sophisticated experimental investigation may produce valuable information to predict the negative skin friction and accordingly the drag load on these piles. This paper presents the results of an experimental investigation on a single end-bearing pile in collapsible soil. The investigation is tailored to measure the soil collapse before and during inundation and the associated drag load on the pile. The theory proposed by Hanna and Sharif in 2006 for predicting negative skin friction on piles due to consolidation of the surrounding soft clay was extended to predict the negative skin friction for these piles in collapsible soils. A proposed design procedure is presented.
Compacted clays are commonly utilized as landfill liners due to their impermeable properties, however, the availability of natural clay soil may be difficult or prohibitively expensive in some regions thanks to the expense of transportation, the local soil availability or regulation. As an alternative hydraulic barrier, a compacted mixture of sand with a low percentage of bentonite (6% to 14%) was used. The purpose of this research is to investigate the applicability of bentonite available in the Egyptian market for controlling the hydraulic conductivity of sand-bentonite mixtures to be used in landfill liners. The study was divided into two phases: first, laboratory tests were conducted to identify the optimum bentonite percentage and bentonite types, using local commercial bentonite products. Then, in two distinct landfill liners layers, full-scale measurements were obtained. The experimental program demonstrated that Bentonite produced and found in the Egyptian market can be utilized in landfill liners with an acceptable quality control procedure to prevent any outcome deviation.
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