Shape correction factors for drying shrinkage of several typical concrete cross-sections

When a concrete member is loaded for a long period of time, creep and shrinkage of concrete gradually develop. The prediction of this time-dependent behaviour is important as it may cause serious serviceability problems in concrete structures. The shape and size of a concrete cross-section and environmental conditions have an important effect on the moisture flow and moisture distribution of a concrete cross-section and affect the drying shrinkage and drying creep behaviour and thus the long-term behaviour of the concrete member. The impact of the shape and size of the cross-section on the net macroscopic temporal strain and curvature due to shrinkage is investigated in this contribution using numerical simulations. A time-dependent analysis is commonly based on equations given by design codes. The effect of moisture diffusion in these equations is included in an empirical manner and is commonly, among others, defined based on the notional size of the element. As a result of the investigations performed in this contribution, simple shape correction factors are proposed which can be applied to the notional size of elements with different shapes in order to improve the accuracy of the time dependent prediction of drying creep and shrinkage of existing code formulations. The proposed correction factor is based on numerical simulations of different geometries (rectangular, circular, T-shaped beams, ribbed plates, box girders, ribbed plates, hollow core slabs, TT-elements) and a wide range of element sizes