The purpose of this study is to propose a formula for estimating the vertical deflection of the floor when a concentrated load is applied on the beam of a thick-plywood subfloor.
In Chapter 1, we described the background and purpose of the research, and steps of the research.
In Chapter 2, we described the construction of an analytical model for a thick-plywood subfloor. First, in order to create an analytical model of the thick-plywood subfloor, we conducted an experiment in which a concentrated load of 1 kN was loaded on the beam for the thick-plywood subfloor with a planar shape of 5.46m x 3.64m. The vertical deflection distribution of the thick-plywood subfloor through the experiments was figured out. Next, an analytical model of the thick-plywood subfloor that reproduces the test results was generated with an analysis-software by finite element method. Finally, the constructed analytical model was verified that reproduced the vertical deformation of the thick-plywood subfloor.
In Chapter 3, the influence of various factors affecting the vertical deflection of the thick-plywood subfloor was examined analytically. Fig. 4 shows the results.
In Chapter 4, we conducted a parameter study. In the analysis, various influence factors such as the bending stiffness of the beam, the span of the beam, the Young's modulus of the plywood, and the shear stiffness of the wood screw that fastens the plywood to the beam were changed. Analytically, we examined the influence of various factors. Fig. 5 shows the effect of various parameters on the vertical deflection of the thick-plywood subfloor.
In Chapter 5, based on the influence of various factors obtained from the analysis, we derived a formula for predicting vertical deflection of the thick-plywood subfloor that takes into account the effects of both composite action and two-way action. The prediction formulas for the vertical deflection in case concentrated load is applied on the beam of on the thick-plywood subfloor were shown as Equations (1) to (3).
In Chapter 6, the applicability of the prediction formula for vertical deflection of the thick-plywood subfloors was examined for two types of floors in real houses and three types of full-scale floors. The estimated vertical deflections of the full-scale floors ranged from 0.81 to 1.16 for experimental results.
In Chapter 7, a summary of this study was stated.
