Bolted Gusset Plate Beam-to-Column Connection

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Solution Overview

Problem

Existing beam-to-column joint connections in structural steel buildings are unreliable for withstanding extreme loading conditions such as earthquakes due to brittle welds, which can lead to fractures and failure, and require skilled welders, limiting their application.

Innovation Solution

An all-field-bolted dual braced/moment resisting frame connection structure using parallel gusset plates to connect beams and columns, eliminating welds and allowing for misalignment tolerance through slotted bolt holes, and an optional adjustable beam seat for precise alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If full-penetration groove welds are used to connect beam flanges to column flanges, then connection strength is improved, but reliability under extreme loading deteriorates due to brittle fracture

Engineering Contradiction:

Improveconnection strengthVSAvoidreliability under extreme loading

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent replaces the welding process (thermal-mechanical system) with a bolted connection system (mechanical fastening system). The beam flanges are connected to column flanges using high-strength bolts through slotted holes in gusset plates, eliminating the brittle weld metal and heat-affected zone that are prone to fracture under seismic loading.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the connection mechanism from continuous weld metal to discrete bolted fasteners with slotted holes. The slotted holes provide rotational capacity and ductility by allowing movement and deformation, transforming the rigid brittle connection into a ductile energy-dissipating system that can withstand extreme loading cycles.

Inventive Principle:

Principle #35Parameter changes

2Strength

If full-penetration groove welds are used to connect beam flanges to column flanges, then connection strength is improved, but ease of manufacture deteriorates due to requirement for skilled welders

Engineering Contradiction:

Improveconnection strengthVSAvoidease of manufacture

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces the welding process (requiring skilled welders, specialized equipment, and complex procedures) with a bolted connection system. High-strength bolts can be installed by less skilled workers using standard tools, significantly improving ease of manufacture while maintaining connection strength through proper bolt selection and installation procedures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If highly-restrained welds are used to connect beam to column, then connection strength is improved, but ductility deteriorates leading to brittle fracture

Engineering Contradiction:

Improveconnection strengthVSAvoidductility

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent changes the connection characteristics from rigid and restrained to ductile and flexible through the use of slotted holes. The slots allow the connection to rotate and deform during seismic events, providing energy dissipation and preventing brittle fracture while maintaining overall connection strength through the bolted fastening system.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The gusset plates with slotted holes act as intermediaries between the beam and column flanges. These slotted holes provide the ductility and rotational capacity needed to prevent brittle fracture, while the high-strength bolts maintain the force transfer capability, thus mediating between strength and ductility requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If parallel gusset plates are used to carry vertical load, then reliability is improved, but device complexity increases

Engineering Contradiction:

ImprovereliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The gusset plates serve multiple functions simultaneously: they carry vertical loads through bolted connections to the column flanges, provide a mounting surface for diagonal braces, and incorporate slotted holes to provide ductility and rotational capacity for the beam-to-column connection. This multi-functionality reduces the need for separate components, offsetting the apparent complexity with functional integration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11021865B2Gusset plate connection of braced beam to column

Publication Date: 2021.06.01 MITEK HOLDING INC

AI summary

A joint connection structure of a building framework includes a column assembly including a column and a pair of gusset plates connected to the column on opposite sides of the column and extending laterally outward from the column. A full-length beam assembly includes a full-length beam having upper and lower flanges and an end portion received between the gusset plates. The full-length beam is bolted to the gusset plates of the column assembly to connect the full-length beam assembly to the column assembly. A brace has an end portion received between the gusset plates and makes an angle with the beam and with the column. The brace is bolted to the gusset plates at the end portion of the brace.