New constructive form of rigid connection of sitecast reinforced concrete ceiling to concrete filled tube column

Abstract

Abstract. Purpose. Concrete filled tube columns have significantly better compression strength than same shape regular reinforced concrete columns. However, the disadvantage of applying the concrete filled tube columns is the complication of providing the rigid connection to sitecast reinforced concrete ceiling. Such type of joining has less ceiling thickness versus to regular rigid joining, using the steel girders, which is important for high-rise buildings. Regarding to this, the task of creating the new constructive form of connection concrete filled tube to sitecast reinforced concrete ceiling, which constructive fulfilment allowed providing the rigid connection sitecast reinforced concrete ceiling to concrete filled tube and decrease the material consumption of reinforced concrete frame was set. Originality. Basing on analyzing of existent researches of constructive forms of concrete filled tube to reinforced concrete ceiling joining and investigation in reinforced concrete area, the new constructive form of rigid connection of concrete filled tube to sitecast reinforced concrete ceiling, which is enhanced by using steel rigid element which consists of vertical steel plates, which cross column concrete core, and welded to steel tube was offered. For providing the rigid connection with concrete filled tube column, construction of ceiling includes the stripes of external steel plate reinforcing, welded to steel rigid element and to concrete filled tube column’s steel casing. Methodology. The comparative finite element analysis modelling of tension-strain conditions of sitecast reinforced concrete ceiling construction with 477mm diameter concrete filled tube columns with link and rigid conditions of joining of ceiling and column and using the stripes of external steel plate reinforcement in case of rigid connection, was made using the Autodesk Robot Structural Analysis. The first model included the regular sitecast reinforced concrete ceiling. The second model included the reinforced concrete ceiling with external steel plate reinforcement, modeled by equivalent rigidness finite elements. Findings. The comparative finite element modelling proved the effectiveness of offered constructive decision by decreasing the bending moments in plate middle area on 40%. Practical value. New constructive form provides the rigid connection of concrete filled tube column to sitecast reinforced concrete ceiling and allows to decrease ceiling height and overall material consumption of reinforced concrete frame.