WO2013103878A1 - Buckling restrained brace with lightweight construction - Google Patents
Buckling restrained brace with lightweight construction Download PDFInfo
- Publication number
- WO2013103878A1 WO2013103878A1 PCT/US2013/020364 US2013020364W WO2013103878A1 WO 2013103878 A1 WO2013103878 A1 WO 2013103878A1 US 2013020364 W US2013020364 W US 2013020364W WO 2013103878 A1 WO2013103878 A1 WO 2013103878A1
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- WO
- WIPO (PCT)
- Prior art keywords
- core
- restrainer
- buckling restrained
- brace
- restrained brace
- Prior art date
Links
- 238000010276 construction Methods 0.000 title description 5
- 239000000837 restrainer Substances 0.000 claims abstract description 90
- 229920002430 Fibre-reinforced plastic Polymers 0.000 claims abstract description 20
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 19
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- 230000006835 compression Effects 0.000 claims abstract description 17
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- 239000004570 mortar (masonry) Substances 0.000 claims abstract description 7
- 125000004122 cyclic group Chemical group 0.000 claims description 42
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C3/00—Structural elongated elements designed for load-supporting
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04H—BUILDINGS OR LIKE STRUCTURES FOR PARTICULAR PURPOSES; SWIMMING OR SPLASH BATHS OR POOLS; MASTS; FENCING; TENTS OR CANOPIES, IN GENERAL
- E04H9/00—Buildings, groups of buildings or shelters adapted to withstand or provide protection against abnormal external influences, e.g. war-like action, earthquake or extreme climate
- E04H9/02—Buildings, groups of buildings or shelters adapted to withstand or provide protection against abnormal external influences, e.g. war-like action, earthquake or extreme climate withstanding earthquake or sinking of ground
- E04H9/021—Bearing, supporting or connecting constructions specially adapted for such buildings
- E04H9/0237—Structural braces with damping devices
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C3/00—Structural elongated elements designed for load-supporting
- E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
- E04C3/29—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces built-up from parts of different material, i.e. composite structures
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C3/00—Structural elongated elements designed for load-supporting
- E04C3/30—Columns; Pillars; Struts
- E04C3/32—Columns; Pillars; Struts of metal
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G23/00—Working measures on existing buildings
- E04G23/02—Repairing, e.g. filling cracks; Restoring; Altering; Enlarging
- E04G23/0218—Increasing or restoring the load-bearing capacity of building construction elements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/32—Investigating strength properties of solid materials by application of mechanical stress by applying repeated or pulsating forces
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C3/00—Structural elongated elements designed for load-supporting
- E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
- E04C2003/026—Braces
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04H—BUILDINGS OR LIKE STRUCTURES FOR PARTICULAR PURPOSES; SWIMMING OR SPLASH BATHS OR POOLS; MASTS; FENCING; TENTS OR CANOPIES, IN GENERAL
- E04H9/00—Buildings, groups of buildings or shelters adapted to withstand or provide protection against abnormal external influences, e.g. war-like action, earthquake or extreme climate
- E04H9/02—Buildings, groups of buildings or shelters adapted to withstand or provide protection against abnormal external influences, e.g. war-like action, earthquake or extreme climate withstanding earthquake or sinking of ground
- E04H9/028—Earthquake withstanding shelters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
- G01N2203/0075—Strain-stress relations or elastic constants
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/026—Specifications of the specimen
- G01N2203/0262—Shape of the specimen
- G01N2203/0268—Dumb-bell specimens
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/026—Specifications of the specimen
- G01N2203/0298—Manufacturing or preparing specimens
Definitions
- a buckling-restrained brace is a structural element designed to withstand cyclic loading in the form of repeated tensile and compressive forces such as from an earthquake or an explosive blast. BRBs add reinforcement and energy dissipation to steel frame buildings to protect them from large deformations by yielding in tension and compression, while at the same time resisting failure due to buckling.
- BRBs have a steel core member and a surrounding tubular member filled with mortar that is designed to resist buckling of the core member when the core member is subjected to compression loading. Although conventional BRBs are adequate in some situations, it would be desirable to provide BRBs having the same energy dissipating performance while having a lower overall weight, which among other advantages makes handling and installation easier.
- buckling restrained brace having a light-weight construction.
- a buckling restrained brace comprises a core member, core restrainer member sections, and a jacket member.
- the core member has two opposite ends.
- the core restrainer member sections are configured to be arranged around the core member.
- the jacket member comprises fiber reinforced polymers configured to be wrapped around the core restrainer member sections and core member to couple the core restrainer member sections to the core member.
- the core restrainer member sections and jacket member cooperate to provide greater resistance to buckling of the core member when the brace is subjected to
- the brace can have a weight less than 50% of a weight of a conventional buckling restrained brace of similar length and having a steel core and mortar- filled tubular core restrainer member of comparable cross- sectional areas, respectively.
- the core member can have a cross section defining at least one pair of opposed spaces configured to receive a respective number of core restrainer member sections.
- the core member can have a T-shaped cross section defining two opposed spaces, wherein each of the two spaces is configured to receive one of the core restrainer sections.
- the core member can be comprised of two-angled sub-members defining a T-shape when positioned adjacent each other.
- the core member can have a cross-section defining at least four separated spaces, wherein each of the spaces is configured to receive one of the core restrainer sections.
- the core member can be comprised of four angled sub-members, and the angled sub-members can be arranged such that the vertices thereof are adjacent but spaced apart from each other in a cross section of the core member.
- the core member can be comprised of two T-shaped sub-members arranged opposite to each other.
- the core restrainer members can be tubular and have a rectangular cross section or a circular cross section, and are sometimes referred to herein as "tubes".
- the jacket member can be sized to extend over an intermediate portion of the core member between the two opposite ends.
- the core member can be formed of a ductile material, such as an aluminum alloy.
- the core member can comprise at least two core member sections and at least one spacer member positioned between the core member sections.
- the spacer member can be formed of a plastic material or fiber reinforced polymers.
- the jacket member can comprise at least one layer of material applied at different angles relative to the core member. In some implementations, two or more layers are used.
- the jacket member can comprise at least one layer of material applied at an angle of about 30 degrees relative to an axis of the core member.
- the core member can be configured to dissipate seismic energy through substantially reversible cyclic plastic strain.
- the core member, core restrainer member sections, and jacket member can be constructed of materials selected to reduce corrosion from exposure to environmental conditions.
- the core member, core restrainer sections, and jacket member are configured to allow the core and the core restrainer sections to translate relative to each other under pre-defined loading conditions imposed on the brace.
- Figure 1(a) is a perspective view of an implementation of a buckling restrained brace having a light weight construction with an intermediate portion of the brace cut away to show the relative positions of various components.
- Figure 1(b) is an enlarged perspective view of a portion of the brace of Figure 1(a).
- Figures 1(c), 1(d), 1(e) and 1(f) are end elevation views of representative braces having different core member and core restrainer member configurations.
- Figure 1(g) is a perspective view similar to Figure 1(a) of another implementation of a buckling restrained brace.
- Figure 1(h) is an enlarged perspective view of a portion of the brace of Figure 1(g).
- Figures 2(a) and 2(b) are side elevation views of a representative brace identifying various dimensions used in modeling.
- Figure 2(c) is an end view of the brace of Figures 2(a) and 2(b) showing bolted connections to gusset plates.
- Figure 3(a) is a set of diagrams showing a single degree of freedom mechanical model for modeling the brace.
- Figure 3(b) is a drawing showing another model of the brace.
- Figure 4 is a scatter plot of required restrainer stiffness vs. restrainer length providing a comparison between analytical and numerical results.
- Figure 5(a) is a drawing showing dimensions for two test coupons.
- Figure 5(b) is a perspective view showing a test apparatus for subjecting a test coupon to a predetermined loading.
- Figure 6 is a graph of stress versus axial strain showing the brace's response to predetermined loading.
- Figure 7 is a graph showing maximum cyclic stress versus a number of reversals for the brace of Figure 6.
- Figure 8(a) is a graph of normalized stress versus axial strain based on testing of another representative coupon.
- Figure 8(b) is a side elevation view of the representative coupon tested in Figure 8(a).
- Figure 9(a) is a perspective view of a core member showing how it is modeled using finite element analysis.
- Figure 9(b) is a graph of axial load versus axial displacement for the model of Figure 9(a).
- Figure 10(a) is a cross section of a core member at an intermediate point showing various dimensions used in modeling brace end moments.
- Figure 10(b) is a diagram illustrating end moments or rotations that the brace of Fig. 10(a) may experience during severe seismic loading.
- Figures 11(a) through 11(f) show axial load versus log-displacement relationships for six groups of simulations.
- Figure 11(g) is a graph of the required restrainer stiffness versus the end moment ratio for two groups of braces.
- Figure 12(a) is a perspective view of a brace showing yielding prior to buckling.
- Figure 12(b) is a perspective view of the brace of Fig. 12(a) showing its deformed shape after buckling.
- Figure 12(c) is an enlarged view of a portion of the brace of Figs. 12(a) and 12(b) that has been subjected to buckling showing that a plastic hinge is created in the area of junction between its full section and its intermediate section.
- Figures 13(a) and Figure 13(b) are graphs of axial load versus axial displacement for one prototype.
- Figures 13(c) and Figure 13(d) are graphs of axial load versus axial strain at mid-length for the prototype of Figs. 13(a) and 13(b).
- Figure 13(e) is a plot of normalized cumulative-displacement versus restrainer stiffness for the prototype of Figs. 13(a) and 13(b).
- Described herein is a new BRB, having an aluminum core member for seismic force dissipation, and fiber reinforced polymers (FRP) arranged to couple tubular core restrainer sections to the core, thus accomplishing the goals of decreased installation weight, increased system compactness and efficient energy dissipation.
- FRP fiber reinforced polymers
- Competing concepts have been characterized as beneficial due to decreased installation cost, having replaceable cores, ability to use low-skilled labor for installation, compact for installation confined spaces, and use in existing building retrofits.
- replaceable shear links constructed of low yield point aluminum installed in concentrically braced frames or special truss moment frames (Rai and Wallace 2000) and replaceable aluminum plate shear panels (Rai 2002, Mazzolani et al. 2004, Brando et al. 2009) have all been proposed and tested with moderate success.
- FRP has successfully been used in structures since the 1970s and has been commonly employed in applications bonded to concrete or steel members requiring strengthening or repair (Zhao and Zhang 2007). More pertinent applications recently have been developed that increase ductility of steel members. For instance, bonded unidirectional sheets wrapped around special truss moment frame chord members enhanced cyclic response of plastic hinge behavior (Ekiz et al. 2004). FRP strips bonded to compression elements of flexural members (Accord and Earls 2006), webs of WT compression members (Harries et al. 2009), and HSS columns (Shaat and Fam 2006, 2007, 2009) have also been reported to delay local buckling of elements subjected to compression.
- the new brace utilizes materials readily available in many sizes and profiles to allow customization of the core-restrainer configuration as shown in Fig. 1(a).
- stock extruded aluminum profiles for the core members should lower procurement and fabrication costs;
- bi-planar symmetry of the brace cross-section should eliminate potential for global buckling in a weak direction;
- non-tapered core cross section dimensions should allow a tight fit to the restrainer tubes without shimming;
- back to back core elements should be continuously supported by high modulus FRP spacers to prevent core rippling;
- sufficient space should be provided at the tip of core elements to allow Poisson expansion;
- unrestrained sections of the core should be sufficiently robust to prevent local or torsional buckling modes;
- the core should be fabricated without welding to prevent material embrittlement and fatigue notching;
- a reduced core section should be used to direct plastic straining to the mid-length of the brace away from
- Seismic forces, story drift, axial displacement, frame geometry and end connections were established within the context of a model building based on the SAC 3-story office building located in Los Angeles, CA (FEMA 2000).
- Two adjacent BRB frames (BRBFs) in an inverted v-brace configuration were centered on each of the four perimeter column lines.
- Figs. 2(a)-(c) show a definition of the brace geometry with a two-step core profile.
- An end to end core length L b 4.83 m [190 in] was generated using assumed W21xl 11 beams and W14xl76 columns to remain consistent with previous literature reports on testing of full-scale BRBFs (Fahnestock et al. 2007).
- Table 1 shows all prototype brace dimensions.
- Flexural stiffness of the elastic restrainer serves to prevent transverse bifurcation of the core hence increasing the critical buckling load P cr .
- the plastic hinge was justified by first considering the internal core moment by combining elastic column Eqs. (4) and (5) for a pinned-pinned column and solving for the internal moment at mid-length M int p at a given transverse displacement A t in Eq. (6). Tangent modulus theory was used to account for core material non-linearity by replacing E c with E ct .
- the resisting moment M res provided by the bundled tube restrainer was calculated from equilibrium on the column half-length shown in Fig. 3a and Eq. (7) where E r and I r are the Young's modulus and moment of inertia of the restrainer, respectively. Comparison of showed approximately two orders of magnitude difference at a common transverse displacement
- Tangent modulus E ct of the core was taken as 1% of Young's modulus to account for strain hardening. The sharp transition between elastic and plastic behavior negates the need for an incremental approach accounting for material non-linearity.
- the prototype to be considered in the numerical simulations used a restrainer stiffness of 33.4 kN/m [0.191 k/in] provided by four 4.25 in x 0.25 in bundled tubes.
- the SDOF model resulted in required stiffness values equal to 82% of the Euler model, indicating that it may be unconservative. However, restrainer stiffness was selected to fall in between these values.
- Alloy 6061-T6511 is a relatively inexpensive heat-treated structural aluminum that is available in many extruded profiles that are conformable to square or round FRP tubes. This alloy has proven to be reliable when limited to the elastic range, but reversed cyclic behavior has not been reported for ⁇ /2 > 4% and required investigation to determine its cyclic behavior such as is reported for plate steels (Dusicka et al. 2007).
- Figs. 5(a) and 5(b) define the monotonic tension and cyclic push-pull coupons machined from 0.875 inch round bar and test setup which used a MTS load frame with a +/- 445 kN [+/- 110 k] capacity.
- cyclic material behavior uses a calibrated general nonlinear combined kinematic-isotropic constituitive model. This model has proven to be capable of simulating the Bauschinger effect, cyclic hardening with plastic shakedown and relaxation of the mean stress (Simulia 2010).
- the calibration procedure used a 3D finite element model of the test coupon comprised of C3D4 tetrahedral continuum elements as depicted in Fig. 8(b). Convergence of the fine mesh was studied by varying the number of degrees of freedom and the element polynomial.
- Coupon simulations were set to run in displacement control for two full cycles to verify calibration. Superposition of three backstresses effectively captured the shape of the experimental hysteresis plots in the Bauschinger region by accounting for strain ratcheting effects. Superposition of the experimental and numerical results for the 2%, 3% and 4% strain amplitudes are illustrated in Fig. 8(a) with reasonable correlation. Isotropic hardening was not used due to its negligible influence on cyclic behavior as shown by the stable maximum cyclic stress plots.
- Numerical models were created using commercially available finite element analysis and post-processor software (Simulia 2010) and configured as shown in Fig. 9(a). Core angles were modeled as four separate 3D planar extrusions meshed with fully integrated, general purpose 4-node shell (S4) elements capable of modeling large membrane strains and the restrainer was modeled as a single ID beam meshed with Timoshenko (B31) elements. Beam element section properties were assigned using equivalent square tubes representative of the x-x and y-y flexural stiffness of the bundled restrainer tubes acting compositely. Core and restrainer nodes were connected with slide-plane connectors to the angle tips and slot connectors to the angle vertex to decouple axial interaction and allow Poisson deformation.
- S4 general purpose 4-node shell
- BRBF in-plane drift may introduce end moments or rotations into the brace during severe seismic loading as shown in Fig. 10(b) for an inverted v-brace configuration.
- This effect causes additional flexural demand on the restrainer above those caused by ideal column buckling models.
- An upper bound end moment that utilizes the available plastic moment of the core's intermediate section M p ' was used to quantify this effect which can be determined by performing a rigorous non-linear push-over analyses of the BRB/BRBF assembly which is beyond the scope of this research.
- the available plastic moment of the axially loaded member is reduced below the value of F y Z as is shown diagrammatically in Fig. 10(a) when all four core angles act compositely by shear transfer occurring at the bolted connections.
- model building was multiplied by two as specified by the cyclic loading protocol for "Qualifying Cyclic Tests of Buckling-Restrained Braces” (AISC 2005).
- Figs. l l(a)-(f) show axial load vs. log-displacement relationships for the six groups of simulations. Each dual plot illustrates the ability of the trial to meet the target axial displacement before reaching the failure criteria.
- the failure criteria were defined as buckling or reaching a limiting transverse displacement at the mid- length of the brace.
- the relationship given in Eq. (14) was derived from where M r and S r
- Fig. 11(g) shows the linear effect of application of end eccentricity on required E r I/L r . Slope of the lines remained constant between the Group A and B braces demonstrating that reduced section length has insignificant effect. Furthermore, end eccentricity may be accounted for by superimposing from 34.4 to 37.2 kN/m of additional stiffness per unit of ⁇ which effectively doubles required E r I/L r for this prototype.
- Fig. 4 illustrates scatter plot comparison between analytical and numerical results.
- conservatism of two or greater may be required to account for material non-linearity, load eccentricity, reasonable transverse displacement as well as possible local buckling effects near the end of the restrainer.
- Table 3 shows test parameters for the Group B brace. Representative hysteresis plots for Group IB prototypes for load vs. axial displacement and load vs. transverse displacement are given in Figs. 13(a)- 13(d). Inadequately restrained braces exhibited large transverse displacement along with pinched hysteresis loops on the compression excursions while adequately restrained braces exhibited full symmetrical loops with minimal transverse displacement. Group IB hysteresis plots of load vs. axial strain at the mid- length of the reduced section demonstrate tension side strain ratcheting for the inadequately restrained brace (96-R1-M0) and nearly symmetrical loops for the adequately restrained brace (96-R3-M0).
- Proprietary wrap systems are common and typically exhibit ultimate tensile strengths of 582 MPa [84.4 ksi] in the primary fiber direction and have an effective laminate thickness of 1.27 mm [0.05 in].
- a truss-like mechanism was conceived using two layers of wrap along the entire length of the restrainer oriented at +/- 30° from the longitudinal axis to resist shear flow in tension through the primary fibers.
- the allowable shear strength of the wrap was calculated as 9.85 kN/cm [5.63 k/in] using a degree of conservatism of 1.5 to account for additional extreme fiber longitudinal stress imparted by bending of the restrainer assembly. Although, additional stress in the wrap from bending is expected to be minimal since the modular ratio of the fabric and tubes is unity.
- the described prototype brace was calculated to weigh 200 kg [440 lb] or 27% and 41% the weight of a traditional mortar-filled tube and all-steel BRB of similar length, core area and restrainer dimensions. Thus, the described prototype brace weighs less than 50% of a comparable conventional brace.
- a single square tube of comparable size (8 in x 1/4 in) was used for the mortar- filled tube. Since the nominal yield strength of common steel and 6061-T6 aluminum are almost identical, similar core sizes were considered fair comparison.
- Nominal unit weight for mild steel, aluminum and concrete mortar were taken as 7860 kg/m J [490 lbs/ft 3 ], 2650 kg/m 3 [165 lbs/ft 3 ] and 2410 kg/m 3 [150 lbs/ft 3 ], respectively. This comparison serves to highlight the considerable weight savings that can be realized with the described brace.
- a buckling restrained brace 10 sometime referred to as a "full cruciform" type.
- the brace has an elongate core member 12 with opposite ends 14, 16.
- At least one spacer member 18 is positioned on the core member 12.
- the core restrainer member sections 20 are coupled together with the spacer member 18 and the core member 12 by a jacket 19 comprising fiber reinforced polymer fabric that is configured to be wrapped around the assembled core member and core restrainer member sections with the spacer member sandwiched therebetween.
- the core member is made of aluminum, although other materials with suitable ductility could be used.
- the ends 14, 16 of the core member 12 are exposed.
- the core restrainer member sections 20 can have a rectangular (or square) cross-section as shown in Figs. 1(a), 1(b), 1(c) and 1(e), a circular cross section as shown for the core restrainer members 24 in Figs. 1(d) and 1(f), or any other suitable cross-section.
- the core restrainer sections may have a hollow tubular configuration over at least a portion of their length.
- the core member may be comprised of a single member or several sub- members.
- the core member 12 is comprised of comprised of four angles 22a, 22b, 22c, and 22d arranged such that adjacent side surfaces are in contact with each other and the vertices are adjacent each other and oriented toward the center as shown.
- the core member 12 can be comprised of two tee members 26a, 26b arranged opposite each other, i.e., with the respective uninterrupted side surfaces facing each other.
- the multiple sub-members are separated from each other, e.g., by the interposed spacer member(s), over at least an intermediate portion of the length of the brace 10.
- exemplary configurations define at least one pair of separated spaces (such as two pair or four spaces as shown in Figs. 1(c)- 1(f)) for receiving the core restrainer member sections.
- a debonding material such as PTFE can be applied between adjacent surfaces of the core restrainer member sections 20 and the core member 12 to ensure that there is no coupling or bonding between the adjacent surfaces. In some embodiments, no such debonding material is used.
- FIG. 1(g) and 1(h) another exemplary embodiment of a buckling restrained brace 210 is shown.
- the brace 210 is similar to the brace 10 of Figs. 1(a) and 1(b), except the brace 210 has an elongate core member 212 formed in a T-shape (shown inverted in the figures), and there are two core restrainer member sections 220 received in the spaces defined on either side of the core member 212.
- a jacket 219 of fiber reinforced polymer fabric is wrapped around the core restrainer member sections 220 and the core member 212.
- the core restrainer member sections 20, 200 are made of fiber reinforced polymers.
- the core member 12, 212 is made of a suitable material, such as, e.g., an aluminum alloy.
- the brace 210 does not include any spacer member, but one or more spacer members can be provided if desired or if required in certain circumstances.
- BRB applied end moment was quantified using an upper bound approach in lieu of performing specific frame analyses in order to account for story drift two times greater than the maximum 2.5% given in typical building codes.
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Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/370,747 US20150000228A1 (en) | 2012-01-06 | 2013-01-04 | Buckling restrained brace with lightweight construction |
MX2014008313A MX2014008313A (en) | 2012-01-06 | 2013-01-04 | Buckling restrained brace with lightweight construction. |
EP13733695.4A EP2800842A4 (en) | 2012-01-06 | 2013-01-04 | Buckling restrained brace with lightweight construction |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201261584066P | 2012-01-06 | 2012-01-06 | |
US61/584,066 | 2012-01-06 |
Publications (2)
Publication Number | Publication Date |
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WO2013103878A1 true WO2013103878A1 (en) | 2013-07-11 |
WO2013103878A4 WO2013103878A4 (en) | 2013-09-06 |
Family
ID=48745451
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2013/020364 WO2013103878A1 (en) | 2012-01-06 | 2013-01-04 | Buckling restrained brace with lightweight construction |
Country Status (8)
Country | Link |
---|---|
US (1) | US20150000228A1 (en) |
EP (1) | EP2800842A4 (en) |
CL (1) | CL2014001797A1 (en) |
CO (1) | CO7111258A2 (en) |
EC (1) | ECSP14012743A (en) |
MX (1) | MX2014008313A (en) |
PE (1) | PE20142122A1 (en) |
WO (1) | WO2013103878A1 (en) |
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WO2015018221A1 (en) * | 2013-08-05 | 2015-02-12 | 东南大学 | Embedded lightweight material body, sleeved concrete buckling restraint support |
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US11649632B2 (en) * | 2018-04-20 | 2023-05-16 | Paul William Richards | Buckling-restrained braces and frames including the same |
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- 2013-01-04 US US14/370,747 patent/US20150000228A1/en not_active Abandoned
- 2013-01-04 PE PE2014001080A patent/PE20142122A1/en not_active Application Discontinuation
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CN106703492A (en) * | 2016-11-15 | 2017-05-24 | 东南大学 | Buckling induction support of casing with inducing unit of groove type |
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CN113901544B (en) * | 2021-09-14 | 2023-05-23 | 浙江工业大学 | Method for controlling spatial separation and restraint of waves in beam structure |
Also Published As
Publication number | Publication date |
---|---|
ECSP14012743A (en) | 2015-09-30 |
PE20142122A1 (en) | 2015-01-07 |
EP2800842A1 (en) | 2014-11-12 |
WO2013103878A4 (en) | 2013-09-06 |
CL2014001797A1 (en) | 2015-01-02 |
EP2800842A4 (en) | 2015-11-11 |
CO7111258A2 (en) | 2014-11-10 |
US20150000228A1 (en) | 2015-01-01 |
MX2014008313A (en) | 2015-03-03 |
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