Normal stress distribution of timber-concrete composite panels with an adhesive shear connection under thermal and humidity loadings

Abstract

Humidity and temperature conditions have a substantial influence on the stresses and total deformation of timber-concrete composite panels, especially in terms of the high rigidity of the shear connection. In the present research, the normal stresses that resulted from the hygrothermal load of timber-concrete composite panels with an adhesive shear connection were analyzed. Three timber-concrete composite panel specimens were placed in controlled climate conditions. Strains in two orthogonal directions were measured. The stress distribution resulted from an approximate analytical calculation model. The results show that the highest stresses occurred near the shear connection. An increase in timber moisture content by 2.1% was predicted to result in exceeding the flexural tensile strength in the concrete perpendicular to the timber grain direction. At an outdoor temperature range, stresses influenced only by the temperature alone will possibly not cause a failure of timber or concrete. Under winter environmental conditions, the stress in timber can possibly reach 12% of the bending strength of the timber used.

The Adhesive Shear Connection of Timber and Concrete Slabs in Humid Environment

“…Based on this expectation, the strain gauges were placed in the middle of the TCC slab span. However, as resulted from the FEM analysis of the warm Environment 3, the highest values of normal stresses were observed not in the middle part of the specimens, as previously expected in [19], but at the edges of specimens (Figures 13 and 14). The thermal expansion coefficient of concrete is almost 9times higher than that of the timber parallel to the grain (in the x-direction), but on the contrary, it is 0.32-times lower than that of the timber perpendicular to the grain (in the z-direction).…”

“…The presented study discusses the potential use of TCC with adhesive shear connection in such humid environmental conditions. The research performed [19] dealt with the behaviour of TCC panels with an adhesive shear connection solely under the hygrothermal load and without other impacts, such as creep from gravity load or concrete shrinkage. The specimen loading was performed in a climate chamber.…”

“…These coefficients for concrete were calculated similarly, but the differences in relative humidity of the environment were used for the humidity expansion coefficient. More can be found in [19].…”

“…The theoretical analysis of the specimens was performed by a finite element method (FEM) using ANSYS software [19]. The geometry of the model corresponded to real specimens.…”