Some restrictions when calculating compressed-bent wooden elements
The basis for the calculation of the upper belts of wooden rod structures under uniformly distributed load is the method of calculating the strength of the compressed-bent elements. This method is based on the theory of longitudinal-transverse bending and adapted for the calculation of rectilinear compressed-bent wooden elements in the first half of the XX century. Since then, this technique has not changed, except for the introduction of correction factors for individual load application schemes. At present, due to the increase in the volume of wooden housing construction, scientific interest in the methods of calculation of compressed-bent wooden elements of various shapes and loading schemes has arisen again. The article is devoted to some restrictions that are recommended to be taken when calculating and designing compressed-bent wooden elements. The need to take into account the deflection when determining the bearing capacity of the structure is considered. The key issue when determining the magnitude of the deflection is the value of the longitudinal force, which as it approaches the critical force gives an intense nonlinear increment of the calculated deflection. It is recommended, when calculating, to limit the value of the longitudinal force to not more than 0.6 of the critical force. An example is given showing that the formula for the strength of the compressed-flexural rod in the normative version of the calculation method does not pay attention to the deflection of the element to be taken into account.