Wave-Shaped Reinforcing Element for Punching Shear Resistance
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Solution Overview
Problem
Punching shear failures occur in concrete components under local increased loads, as they cannot absorb transverse forces within their concrete load-bearing capacity, leading to potential structural failures.
Innovation Solution
A wave-shaped reinforcing element with inclined waves is introduced into the concrete reinforcement system, where the waves are angled to align with the direction of the increased load, enhancing the punching shear resistance by distributing the load effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional straight reinforcement bars are used, then the concrete load-bearing capacity is maintained, but the punching shear resistance is insufficient under local increased loads
Solution Approach 1:
The reinforcement bar is formed with corrugations featuring rounded fourth sections connecting straight third sections, creating a curved wave-shaped profile. This curvature enables the reinforcement to better distribute localized loads and resist punching shear forces compared to straight bars, while maintaining manufacturability through standard corrugation forming processes.
Solution Approach 2:
The corrugations are strategically positioned and oriented with specific section angles (10° ≤ α ≤ 80°) to address the local stress concentration at punching shear critical sections. The wave-shaped profile creates localized reinforcement zones that specifically target areas of high shear stress without requiring complete structural redesign.
2Strength
If the section angle of reinforcing corrugations is increased to improve load distribution, then the punching shear resistance increases, but the manufacturing complexity increases
Solution Approach 1:
The section angle α of the corrugations is optimized within the range 10° ≤ α ≤ 80° (preferably 30° ≤ α ≤ 75° or 50° ≤ α ≤ 60°) to achieve effective load distribution. This parameter optimization balances manufacturing feasibility with structural performance, avoiding excessively steep angles that would be difficult to form while ensuring sufficient shear resistance.
Solution Approach 2:
The corrugations extend partially along the reinforcement bar length rather than requiring complete coverage, with the wave pattern concentrated at critical sections. This partial action approach provides sufficient punching shear resistance at key locations without the manufacturing complexity of fully corrugated bars throughout their entire length.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Reinforcing element (3) for a punching shear reinforcement system (10) for a concrete structural element, comprising at least one corrugated reinforcing bar (30) with a first free end and a second free end opposite it, wherein reinforcing waves (303;304) are formed in a third direction (Z), and wherein at least one inclined reinforcing wave is provided which comprises straight third parts (303) which extend at a part angle of 10° ≤ α ≤ 80° with respect to the third direction (Z), whereby the at least one inclined reinforcing wave is inclined towards the second free end of the reinforcing bar (30).