Dissipative Façade Bracket for Blast Load Mitigation

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Solution Overview

Problem

Current blast-resistant façade designs face challenges in managing blast wave energy dissipation and reducing the risk of progressive collapse, while also addressing the hazards of glass fragmentation and load transfer to the building structure, with a need for more efficient energy-absorbing anchoring systems that do not significantly increase fabrication and installation costs.

Innovation Solution

A dissipative façade anchoring system that deforms significantly beyond a certain load threshold, reducing peak reaction forces by 50-70% compared to traditional rigid load transfer brackets, and is designed to maintain structural integrity and mitigate hazards both inward and outward from the building, using a combination of dissipative elements and a balanced design approach that optimizes resilience and protection performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional rigid anchoring systems are used to transfer blast loads to the building frame, then structural strength is improved, but peak reaction forces increase significantly and risk of progressive collapse increases

Engineering Contradiction:

Improvestructural strengthVSAvoidpeak reaction forces

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

The anchoring system transitions from a static rigid connection to a dynamic system that changes its mechanical behavior based on load conditions. Under normal service loads, the bracket maintains a rigid elastic connection, but under extreme blast loads exceeding the activation threshold, it dynamically transforms into a dissipative mechanism with controlled plastic deformation, allowing the system to adapt its stiffness characteristics to the applied load level

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The bracket's mechanical parameters (stiffness, strength, deformation capacity) are specifically designed and tuned to change at a predefined load threshold. The yield strength and plastic deformation capacity are calibrated so that the bracket activates its energy-dissipating mechanism only when blast pressures exceed normal operational loads, thereby maintaining rigidity during service while limiting peak reactions during extreme events

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If rigid anchoring systems are used to maintain façade stability, then structural integrity is improved, but glass fragmentation hazards and framing stresses increase

Engineering Contradiction:

Improvefaçade stabilityVSAvoidglass fragmentation hazards

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The invention converts the potentially harmful rigid connection that transmits full blast forces to the glass and framing into a beneficial dissipative mechanism. By allowing controlled plastic deformation in the bracket, the system transforms the harmful peak loads into useful energy dissipation, thereby protecting the glass panels from catastrophic fragmentation while maintaining overall façade stability

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Force

If energy-absorbing deformable brackets are used to reduce peak reactions, then load transfer to building frame is reduced, but bracket deformation capacity requirements increase

Engineering Contradiction:

Improveload transfer to building frameVSAvoidbracket deformation capacity requirements

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The bracket is designed with specific material and geometric parameters (yield strength, cross-sectional area, moment of inertia, plastic section modulus) that are tuned to achieve the desired deformation capacity. These parameters are calculated based on the target peak reaction reduction (50-70%) and the expected blast load spectrum, ensuring the bracket has sufficient deformation capacity without excessive complexity

Inventive Principle:

Principle #35Parameter changes

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 dissipative anchoring system effectively reduces the load transfer to the building frame, minimizes glass and framing stresses, and enhances safety by allowing controlled deformation, thereby reducing the risk of progressive collapse and glass fragmentation hazards, while providing cost-effective and efficient blast resistance.

Implementation Method 1

beyond a certain predefined and tuned value, the anchoring system deforms significantly, following a controlled resistance versus deformation plateau

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

The anchoring system is designed to resist as a rigid elastic element when subject to traditional loads such as dead loads, wind, impacts

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS11499332B2Dissipative bracket to mitigate effects of explosions on building facades

Publication Date: 2022.11.15 PERMASTEELISA

AI summary

A glazed façade anchoring system to a building including a box with a connection system to the façade and connection to the building slab. The first and second connections enable relative movement between one another, when the façade moves within the gap between the rear surface of the façade and the building slab edge under the high pressure loads due to exceptional events such as explosions. The device includes one or more solid elements with dissipative components acting in compression in the inward building direction and one or more solid elements with dissipative components acting in compression in the outward building direction.