Rolled Thread Pile Shaft for High Load Anchoring
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Solution Overview
Problem
The carrying capacity of ground anchors is limited by the mobilized earth resistance of the anchor plate, and existing technologies face challenges in achieving secure fastening of pile shafts in soil objects under varying loads and conditions.
Innovation Solution
A Bohrverpresspfahl with a pile shaft featuring a rolled external thread of greater slope than the anchor head, providing improved bond stress and crack distribution, and optionally rounded edges and thread grooves for enhanced durability and corrosion resistance, allowing for higher load capacities and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional external thread is used on the pile shaft, then the structure is simple to manufacture, but the bond stress in the grout is insufficient and cracking occurs under large loads
Solution Approach 1:
The patent changes the geometric parameters of the external thread by rolling it instead of cutting it, creating a greater slope angle and rounded edges that improve bond stress distribution in the grout without requiring additional corrosion protection layers
Solution Approach 2:
The rolling process creates rounded edges on the thread projections and grooves, which distributes stress more evenly and prevents stress concentration points that would lead to cracking under load
2Reliability
If additional corrosion protection is applied to prevent cracking, then the durability is improved, but the device complexity and manufacturing steps increase
Solution Approach 1:
The rolled thread geometry itself provides the corrosion resistance function through its rounded edges and stress distribution characteristics, eliminating the need for separate corrosion protection layers while maintaining durability
3Force
If the thread slope is increased to improve bond stress, then the load capacity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent replaces the conventional cutting process with a rolling process that inherently creates the desired greater slope angle and rounded edges through plastic deformation, achieving the required geometry with standard manufacturing tolerances rather than precision machining
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 solution enables secure fastening and high load-bearing capabilities, with internal capacities up to 3,865 kN, minimal deformation, and robustness in both cohesive and non-cohesive soils, suitable for marine and civil engineering applications.
Implementation Method 1
the bond stress is improved in the grout and, consequently, achieve a more even cracking
Implementation Method 2
the edges formed during rolling of the external thread are rounded. Thus, the bond stress is improved in the grout and, consequently, achieve a more even cracking
Implementation Method 3
Such an inventive solid rod with said threaded particular requires no additional corrosion protection, which is otherwise required in order to avoid cracking of the concrete
Data Source
AI summary
The invention relates to a drilled and grouted pile with a pile shaft made of round steel and an anchor head having an external thread on which a head plate can be fastened by means of a nut, for anchoring, in particular of sheet pile walls. To enable secure fastening of the pile shaft in the ground, the invention proposes that the pile shaft be provided with a rolled external thread along its entire axial length, having a larger pitch than the external thread in the drill head, preferably a thread pitch of 15 mm to 25 mm.