Thermo-Hygral Analysis on Long-Term Natural Frequency of RC Buildings with Different Dimensions

Abstract

Gradual decay of natural frequency of reinforced concrete (RC) buildings is computationally investigated in view of the long-term moisture loss and associated shrinkage of concrete. The thermo-hygral analysis for RC lifetime over several decades is applied with monitoring data of existing multi-story buildings and nuclear power plants in service. The reduced natural frequency is numerically reproduced with delayed cracking near junction planes between structural members of different dimensions in multi-story buildings and dispersed cracks close to the surfaces of RC thick walls of nuclear power plants. In order to quantitatively clarify the impact of drying shrinkage, both sealed and open boundary conditions for moisture migration are assumed at simulation. It is also confirmed logically that the rate of decay for the natural frequency of the middle story RC building is faster because of the small thickness of walls, slabs and columns compared to structural members of nuclear power plants.

Effect of early age drying shrinkage on the seismic response of RC structures

“…Unfortunately, no experimental work was conducted to validate the numerical simulations. In [17], numerical simulations using a Thermo-Hygral model were performed on RC structures of dierent dimensions in order to show that the decrease of natural frequency due to early age eects is more important in structures having a small thickness. In [18] authors modeled the dynamic behavior of a 28 story building of real size kept in either endogenous or non-endogenous conditions using a FEM approach.…”

Impact of Drying on Structural Performance of Reinforced Concrete Beam with Slab

“…However, studies by the authors have shown that the frequency of concrete structures decreases (i.e., the stiffness of the structure decreases) with the change in material properties with age and for different curing conditions [13][14][15][16]. To prevent the failure of RC buildings, any change in the mechanical properties of the structures due to changes in the material properties should be investigated and considered in design methods.…”

Drop-Weight Impact Loading of Polypropylene Fiber Reinforced Concrete Wall after One-Year Drying Shrinkage

“…Until now, drying shrinkage cracking of reinforced concrete (RC) has been viewed only as one of the causes of steel bar corrosion or as a problem of external aesthetics. However, several finite element analyses of full-modeled RC buildings, made possible by recent advancement in numerical techniques, indicate that shrinkage cracking probably affects the seismic performances of structures (Kurihara et al 2017;Kitazawa et al 2018). Figure 1 shows the seismic behavior of a 22-story RC wall building, analyzed in a study by some of the authors (Kitazawa et al 2018).…”