Adjustable Column Uplift-Resisting Assembly
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Solution Overview
Problem
Existing support columns, such as the WM series, are inadequate in resisting uplift loads caused by wind and seismic activity, failing to meet current building codes, particularly section 9.23.13 of the National Building Code, which requires enhanced bracing to resist lateral loads.
Innovation Solution
An uplift-resisting assembly is introduced, featuring a tubular member with a housing and threaded rod system that transfers uplift loads from a top plate to the tubular member, utilizing washers and a housing design with side walls to secure the assembly and resist uplift, while allowing for height adjustment without compromising structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional support columns are used, then the structure can support vertical loads, but the columns cannot resist uplift loads caused by wind and seismic activity
Solution Approach 1:
The column is divided into a tubular member and a separate uplift-resisting assembly. The uplift-resisting assembly includes a housing with side walls that can be selectively attached to the tubular member, allowing the column to function in both simple compression support mode and enhanced uplift resistance mode depending on loading conditions
Solution Approach 2:
The uplift-resisting assembly serves multiple functions: it provides uplift resistance through the housing and threaded rod mechanism, allows height adjustment of the column, and can be selectively engaged or disengaged based on whether uplift resistance is needed. This multi-functional design adds uplift capability without requiring a completely different column type
2Ease of manufacture
If the column structure is simplified, then manufacturing and installation are easier, but the moment carrying capacity and uplift resistance are insufficient
Solution Approach 1:
The uplift-resisting assembly is designed to be self-contained and self-installing. The housing with side walls attaches to the tubular member using the threaded rod mechanism that is integral to the assembly itself, eliminating the need for separate welding or complex fastening operations. The assembly essentially installs itself through the threaded engagement mechanism
Solution Approach 2:
The threaded rod is received within the bore of the tubular member, and the housing encloses the threaded rod mechanism. This nested arrangement allows the uplift-resisting components to be compactly integrated with the main column structure without requiring additional space or complex external attachments
3Reliability
If permanent support devices are used, then structural stability is improved, but the devices become complex and difficult to adjust
Solution Approach 1:
The column design transitions from a static, fixed-height structure to a dynamic, adjustable system. The threaded rod mechanism allows the top plate to be moved vertically along the tubular member by rotating the threaded rod, enabling height adjustment while the column remains installed in the structure. This dynamic capability maintains reliability while improving operability
Solution Approach 2:
The threaded rod acts as an intermediary mechanism between the top plate and the housing. By rotating the threaded rod, the top plate can be adjusted in height without disturbing the housing's attachment to the tubular member. This intermediary mechanism decouples the height adjustment function from the structural attachment function, allowing independent optimization of both
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The uplift-resisting assembly effectively meets or exceeds current building codes by providing significant resistance to uplift loads, with tested columns demonstrating increased resistance to failure under tension, achieving average failure forces of approximately 11,076 lbs before top connection failure, compared to prior art which failed at around 4000 lbs.
Implementation Method 1
A threaded rod extends through an opening in a top of the housing and an opening in the closed top end of the tubular member and into the bore thereof
Implementation Method 2
An adjustment nut is threaded to the threaded rod and is rotatably positioned between the top of the housing and the closed top end of the tubular member for adjusting an effective height of the column
Implementation Method 3
A housing, having a top with an opening formed therein for the threaded rod, at least one side wall extending therefrom for connection to the tubular member
Implementation Method 4
The adjustment nut bears against the top of the housing in uplift and against the closed top of the tubular member in compression
Data Source
AI summary
An uplift-resisting assembly, connected to a top of a tubular member of a height adjustable structural column, acts to transfer load, particularly uplift loads imposed on the structure to which the column supports, therethrough and into the tubular member. The housing of the assembly is connected to the tubular member, which is connected to a base such as a footing. A threaded rod extends through the housing and into the tubular member. A top plate, connectable to a structure above is attached to the top of the threaded rod. An adjustment nut, threaded onto the threaded rod for adjusting the height of the column is sandwiched between the top of the housing and the top of the tubular member. The adjustment nut bears on the tubular member in compression and bears on the top of the housing during uplift, the uplift being transferred via the housing into the tubular member.