Column End Joint Structure for Wooden Buildings
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Solution Overview
Problem
Existing column end joint structures in wooden buildings are prone to splitting stress at the joint portions between columns and foundations or beams, leading to reduced resistance against bending moments and shearing forces, especially when high forces are applied during earthquakes.
Innovation Solution
A column end joint structure with cutout portions at both ends of the column, where joint fittings are arranged to distribute tensile and compression forces and resist shearing forces, minimizing splitting by distributing loads and restraining displacement through multiple joint bolts and fittings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a screw member and bolt are threaded into the column at positions in the vicinity of both ends in the longitudinal direction of the cross-section to resist bending moment, then the joint portion can resist bending moment effectively, but splitting is generated more easily at the column
Solution Approach 1:
The patent applies local quality by positioning joint fittings at specific locations on the column end face - one at the end edge and another at the center or opposite end edge. This strategic positioning allows different regions of the column to handle different stress types: the end-edge fitting handles bending moment while the center fitting reduces splitting stress, creating locally optimized stress distribution throughout the joint structure.
2Strength
If multiple joint fittings are arranged in the longitudinal direction of the end face to distribute tensile and compression forces, then the resistance to bending moment and shearing force is enhanced, but the device complexity increases
Solution Approach 1:
The patent segments the joint fitting arrangement into distinct functional units positioned at different locations on the end face. By dividing the load-resisting function across multiple separated fittings rather than using one large complex fitting, the structure can distribute tensile and compressive forces more effectively while maintaining manageable complexity through modular, standardized fitting components.
Data Source
AI summary
In a column end joint structure for joining an end of a column made of flat wooden material having a rectangular cross-section to a joining member, splitting generation at the end of the column is controlled. An expansion of crack is controlled when splitting generated. A cutout portion is provided in each of ends in a longitudinal direction of a column end face, and a joint fitting is coupled inside the cutout portion by a joint bolt. The joint fitting is coupled to a foundation by an anchor bolt. Joint fittings are arranged in the longitudinal direction of the end face inside each cutout portion. One joint fitting is located contacting or close to a surface of the column inside the cutout portion such that the joint fitting side face and the surface of the column inside the cutout portion restrain a displacement orthogonal to the column axis.