Buckling Restrained Brace: Enhancing Building Seismic Performance

Structure of buckling restrained brace

BRB-01: BRB structure

Buckling restrained brace (BRB) is an innovative structural support device designed to enhance a building's resistance to lateral loads like earthquakes. A BRB consists of four components: a core unit (yielding steel core), an outer restraining unit (steel tube), a unbonded material between the core unit and the outer restraining unit, and the filling material (mortar). The BRB exhibits ideal elastic-plastic behavior, maintaining stable performance under repeated cyclic loads. This significantly enhances the ductility and seismic capacity of structures. Besides, it avoids the compressive buckling failure common in conventional braces, making it suitable for both new construction and reinforcing existing buildings and providing an economical and reliable seismic solution.

Working Principle

The BRB does not buckle under load, providing a stable lateral stiffness to effectively control the overall deformation of the structure. Under seismic action, the BRB will first enter the yielding state, dissipating seismic energy through the plastic deformation of the steel core while providing additional damping, significantly reducing the impact of the earthquake on the structure. This mechanism of 'yielding but not buckling' makes the BRB a key component in enhancing the seismic performance of structures.

Working principle of ordinary brace

BRB-02: Working principle of ordinary brace

Working principle of buckling restrained brace

BRB-03: BRB working principle

Category

BRBs are divided into circular BRBs and square BRBs by shape. Colors are not standardized and can be customized per project requirements, with common options including yellow, white, and gray.

A blue circular buckling restrained brace

BRB-04: Blue circular buckling restrained brace.

One gray and two white square buckling restrained braces arranged in order

BRB-05: Gray and white square buckling restrained brace.

Three yellow square buckling restrained braces stacked together

BRB-06: Yellow square buckling restrained brace.

Specifications

  • Material: Steel
  • Yield force: 500–1500 kN
  • Axis length: 5500–8000 mm
  • Product length: 3500–6000 mm
  • Reference product yield displacement: 4.7–8.3 mm
  • Exterior size: 150 mm × 150 mm, 200 mm × 200 mm

Table 1: Buckling Restrained Brace Specifications

Model Yield Force (F) Axis Length Product Length Reference Product Yield Displacement Exterior Size (Width × Height)
(kN) (mm) (mm) (mm) (mm)
BRB500-3500 500 5500 3500 4.8 150 × 150
BRB500-4000 6000 4000 5.6 150 × 150
BRB500-4500 6500 4500 6.3 150 × 150
BRB500-5000 7000 5000 6.8 150 × 150
BRB500-5500 7500 5500 7.6 150 × 150
BRB500-6000 8000 6000 8.1 150 × 150
BRB750-3500 750 5500 3500 4.7 200 × 200
BRB750-4000 6000 4000 5.5 200 × 200
BRB750-4500 6500 4500 6.2 200 × 200
BRB750-5000 7000 5000 6.9 200 × 200
BRB750-5500 7500 5500 7.6 200 × 200
BRB750-6000 8000 6000 8.1 200 × 200
BRB1000-3500 1000 5500 3500 4.7 200 × 200
BRB1000-4000 6000 4000 5.5 200 × 200
BRB1000-4500 6500 4500 6.3 200 × 200
BRB1000-5000 7000 5000 6.7 200 × 200
BRB1000-5500 7500 5500 7.4 200 × 200
BRB1000-6000 8000 6000 8.2 200 × 200
BRB1500-3500 1500 5500 3500 4.8 200 × 200
BRB1500-4000 6000 4000 5.5 200 × 200
BRB1500-4500 6500 4500 6.3 200 × 200
BRB1500-5000 7000 5000 6.7 200 × 200
BRB1500-5500 7500 5500 7.6 200 × 200
BRB1500-6000 8000 6000 8.3 200 × 200
  • Stiffness ratio after yield: 0.035. Recommended core material: Q235B.
  • If other parameters are required, production can be customized according to design requirements.

Common Core Plate Material Properties

Table 2: Common Core Plate Material Properties

Material Symbols Yield Point Tensile Strength Yield Ratio Elongation
(N/mm2) (N/mm2) (%) (%)
BLY100 100±20 200–300 ≤ 60 ≥ 50
BLY160 160±20 220–320 ≤ 80 ≥ 45
BLY225 225±20 300–400 ≤ 80 ≥ 40
Q235B 220±15 370–500 ≤ 82 ≥ 25

Installation

Installation method of a single diagonal buckling restrained brace

BRB-07: Single diagonal type buckling restrained brace.

Installation method of two double diagonal buckling restrained braces

BRB-08: Double diagonal type buckling restrained brace.

Features

  • Optimized cross-section design
  • Excellent ductility
  • Dual functions of bracing and damping
  • Seismic displacement control
  • Simple connection method
  • Post-earthquake maintainability

Applications

The BRB systems, with their outstanding performance and cost-effectiveness, have emerged as an ideal choice for both new construction and reinforcement projects, elivering reliable seismic safety and protection for diverse building types.

  • High-rise buildings
  • Airports and transportation hubs
  • Schools and hospitals
  • Conference and exhibition centers
  • Industrial workshop
High-rise building frame using red square buckling restrained brace

BRB-09: For high-rise buildings

School exterior using white circular buckling restrained brace

BRB-10: For schools

Exhibition center exterior using brown circular buckling restrained brace.

BRB-11: For exhibition centers

Yellow square buckling restrained brace used in industrial buildings.

BRB-12: For industrial buildings