Serviceability Analysis of Reinforced Lightweight Aggregate Concrete Beams
With its widespread adoption, concrete is an indispensable building material for urban and transport infrastructure. However, the high density of concrete significantly increases the dead load of structures, and that in turn leads to more massive members and higher foundation costs. To reduce the self-weight, the use of lightweight aggregate concretes (LWAC) is a prominent solution. However, the absence of reliable constitutive models and design approaches has restricted the structural application of LWAC. The present research focuses on the serviceability behaviour of reinforced LWAC beams subjected to short-term loading. The experimental programme encompasses eight beams with the reinforcement ratio varied from 0.30% to 0.55% tested by the authors. The inverse analysis approach is applied for deriving a tension-stiffening model of LWAC member. The model was derived with the elimination of shrinkage effect, which is vital for adequate evaluation of the deformation behaviour of reinforced elements made of LWAC (due to relatively large shrinkage deformation and low cracking resistance of the concrete material). The derived model was verified with the employment of nonlinear finite element software ATENA in conjunction with the test results from a number of beams reported in the literature. The comparative analysis reveals satisfactory accuracy of the proposed model: the relative prediction errors were within the 5% interval. The experimentally obtained crack spacing of beam specimens is also compared with the computed crack spacing, and the results are in good agreement.
Keywords- Crack spacing, Deformations, Inverse analysis, Lightweight aggregate concrete, Serviceability, Short-term loading, Tension-stiffening.