Analysis of Collar Roof Considering Deflection of Reinforced Concrete Rim with Cracks

Abstract

This paper deals with the interaction between collar roofs and the bottom support structure made as a reinforced concrete rim. In present, the collar roofs are widely used for their ability to omit internal vertical support structures (columns, support walls), which might be sometimes a complication during a design of the layout of the building. Collar roof acts on the bottom support structure of the building by quite big lateral horizontal forces. For structure analysis of collar roof is often assumed the infinity stiffness of the reinforced concrete rim. The correctness of this assumption depends of the constructional solution of the concrete rim anchoring. When the concrete rim is anchored to the transverse wall only, the assumption of infinity stiffness of the reinforced concrete rim is not fulfilled properly. The paper shows the example of the collar roof supported on the reinforced concrete rim. There is made a comparison of internal forces in two frames. One frame has rigid lateral support; the second one has a flexible lateral support. The flexibility of the lateral support is due to the deflection of the reinforced concrete rim. The occurrence of cracks in the reinforced concrete rim is taken into account. This paper shows the possibility how to deal with the considering cracks in reinforced concrete beam in calculation without using software, which is able to calculate reinforcement concrete beams with steel reinforcement and cracks in concrete.