الفهرس 
Lightwelght structural concreteOnly 14 pages are availabe for public view
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Abstract
Some times the need to reduce the weight of a structural element is not less important than increasing its strength, especially in heavy structures such as tall buildings and bridges where the structure’s weight is one of the main problems that faces the designers. In spite of the increasing use and demand of Lightweight Concrete (LWC), the conceptual and structural design aspects for buildings made from LWC and Infra-Lightweight Concrete (ILWC) have not been adequately explained. Issues such as element dimensions, connections, and reinforcement types and details as well as short and long-term deformations and dynamic behaviour for LWC structures should be covered in up-to date codes. Therefore, this study deals with conceptual and structural design of buildings made from LWC and ILWC and generally consists of two main objectives: - Development and production of new mixtures for LWC and ILWC with minimized dry density and very good mechanical and physical properties. - The ability to apply and involve these new materials in the construction field through intensive series of experimental tests on different structural elements and connections under static and dynamic loads. In order to achieve the first objective in the study, two targets were defined, the first: fair-faced ILWC for walls with minimum dry density (ρmin < 800 kg/m³), minimum thermal conductivity enough to eliminate the heat insulation materials, and maximum strength enough to resist the vertical bearing stress from floors. The second target: fair-faced LWC for construction of floor slabs and beams with minimum dry density, minimum thermal conductivity and maximum strength enough to resist flexural and shear stresses comparable to normal concrete (NC). Once the ILWC and LWC materials were developed and their mechanical and physical properties were determined, a series of large-scale experiments was conducted. For ILWC, a real application i.e. a one-family house in Berlin, was built in 2006. Because of its favourable physical properties and its good durability, ILWC reinforced with GFR was used for the first time as monolithic cast-in-site concrete to construct the outer walls of this house without any additional insulation [Schlaich M., et. al., 2008]. Infra-lightweight concrete is an engineered high-tech material whose potential and various other design aspects are not yet fully exploited. The study shows the limits of ILWC, but also its great potential for fair-faced concrete buildings. For LWC, eight beams constructed from the newly developed LWC mixture with concrete strength class of LC 30/33 and reinforced with glass-fibre bars and steel bars, in addition to two control beams constructed from normal concrete C 30/37 and reinforced with steel bars, were tested experimentally for flexural strength capacity, shear strength capacity, ductile behaviour and bond behaviour in tension and compression zones of the beams. from the economic point of view, using LWC in construction of the floor slabs in tall buildings will reduce the total costs of tall buildings through the reduction of the amount of steel reinforcement, the reduction of foundation volume, and the reduction of vertical members’ cross-sections that saves the used horizontal area. Because they are the most affected components of tall buildings during earthquake excitations, an experimental study was done to investigate the behaviour of interior and exterior joints between LWC beams and NC columns under seismic loads. The development of highly damage-tolerant beam-column connections would allow structural engineers to design joints for moderate shear distortions which exhibit little damage, reduce rotation demands in beam plastic hinges, and eliminate the need for post-earthquake joint repairs. One option for achieving this goal is to use LWC beams which were reinforced with glass-fibre reinforcement bars with superior deformation capacity in beam-column connections.