Load bearing capacity and cracking resistance to off-center compression of hollow concrete blocks

Abstract

The research is about concrete hollow blocks that have been and still are used widely in basement wall construction. It shows that only 10… 30% of their strength is used even for mid and high-rise construction. Therefore massive foundation blocks should be made with hollows. By design, optimized blocks can be combined into the following groups: with large cavities, open from below, with vertical closed and through cavities, horizontal cavities and ribbed. The developed designs of effective blocks of walls of basements potentially give the chance to facilitate them considerably and to save concrete. However, almost of the proposed solutions have not been widely used in practice - mainly due to technological problems. It is necessary to continue the search for effective structural and technological solutions of basement wall blocks and their research. The article shows the result of experimental and theoretic research of two types of concrete blocks: FBH-1 with two top opened hollows and FBH-2 with 4 enclosed hollows. FBH-2 block has hollows with arbolite insertions. His type is efficient for basement external wall due superior thermal performance. The blocks were texted as a part of 3-storey masonry of 1.8 m height applying off-centric loads to it. Those texts allowed to get its actual strength capacity as well as cracking resistance. The load bearing capacity and cracking resistance have been calculated using a deformation method according to current codes. The method takes into account an idealized diagram of concrete stretching.The calculations according to developed method showed satisfactory matching with experimental data of load bearing capacity and cracking resistance.