Gable End Frame Permanent Bracing Arriostre Permanente de Armazones Hastiales
Inadequate design and/or construction can lead to several possible modes of failure. Un diseño o construcción incorrectos pueden dar lugar a fallos en la estruc-tura.
Examples of gable end frame perma-nent bracing to resist lateral loads. Ejemplos de apun-talamientos perma-nentes del armazón hastial para resistir las cargas laterales.
The goal of gable end frame bracing is to transfer the lateral loads applied perpendicular to the gable end frame safely into the roof and/or ceiling diaphragm(s) and the wall. La meta es transferir de forma segura las cargas laterales aplicadas perpen-dicularmente al armazón hastial a la pared o a los diafragmas de techo.
Lateral Force Transfer to Roof and Ceiling Diaphragms
Roof DiaphragmGable End Frame
Ceiling Diaphragm
Structural Sheathing
End wall
Potential Modes of Failure
Connection failure between top of end wall and bottom of Gable End Frame
Excessive bow in Gable End Frame
Ceiling and finish cracking and related serviceability issues (i.e., construction defects)
Diagonal bracing and blocking by Building Designer
Ceiling diaphragm
Gable End Frame by Truss Designer
Horizontal L-reinforcement
if required by Building
Designer. Design attachment
to resist both compression and
tension forces.
Gable End Frame-to-wall
connection by Building
Designer
Gable End Frame
by Truss Designer
Gable End Frame-to-wall
connection by Building
Designer
Blocking by Building Designer
Bottom Chord Continuous Lateral Restraint and Diagonal Braces. See BCSI-B3 or as specified by the Building Designer
Blocking by Building Designer
Roof diaphragm
Gable end wall Permanent Diagonal Bracing by Building Designer
Most manufactured gable end frames contain only flat vertical “studs” (as opposed to trian-gulated web members) and are designed to transfer roof loads (i.e., gravity and/or uplift) acting vertically in the plane of the frame directly into a continuous structural bearing below. Any web member reinforcement, shown on the Truss Design Drawing (TDD) for the gable end frame, is required to prevent column buckling of the web members due to the vertical loads applied to the frame.La mayoría de armazones hastiales fabricados contienen solamente montantes planos y verticales (a diferencia de las viguetas triangulares) y están diseñados para transferir cargas de techo (p. ej.: gravedad o elevación) directamente a un soporte continuo inferior actuando vertical-mente en el plano del armazón. El refuerzo de las viguetas, como se muestra en el dibujo de diseño de la armadura (Truss Design Drawing, TDD) para el armazón hastial, es necesario para evitar que las columnas de las viguetas cedan debido a las cargas verticales aplicadas sobre el armazón.
In service, gable end frames often experience lateral loads applied parallel and perpendicular to their plane from wind and/or seismic events. Gable end frames are not designed to resist these loads but rely on properly designed and installed structural sheathing, bracing, and connections to the bearing wall, roof and ceiling diaphragms to adequately resist and transfer these lateral loads.Una vez montados, los armazones hastiales a menudo soportan cargas laterales aplicadas para-lela y perpendicularmente a sus planos en caso de seísmo o viento. Los armazones hastiales de-penden de que el entablado estructural, el apuntalamiento y las conexiones estén correctamente diseñados e instalados en la pared de soporte y en los diafragmas de techo para resistir y transferir esas cargas laterales adecuadamente.
The building designer may decide to design a balloon-framed end wall, which eliminates the need for a gable end frame (Figure A). If a gable end frame is used, it must match the profile of the adjacent trusses to ensure the top of the end wall aligns with and is braced by the ceiling diaphragm (Figure B).
CAUTION A flat bottom chord gable end frame used with adja-cent trusses that have sloped bottom chords (Figure C) creates a condition in which the top of the end wall and bottom of the gable end frame cannot be supported directly by the ceiling diaphragm. This condition is prohibited by the prescriptive requirements of the building code and requires special end wall bracing design consid-erations by the building designer.
Truss Designers may provide standard design tables and details to assist the building designer in determining the bracing and/or reinforcement required to transfer lateral loads due to wind and/or seismic forces from the gable end frame into the roof and/or ceiling diaphragm. These tables and details do not take the place of a complete flow of loads analysis by the building designer.
Los diseñadores de armaduras pueden proporcionar tablas de diseño estándar e información para ayudar al diseñador estructural a determinar el apuntalamiento o refuerzo necesario para transferir las cargas laterales provocadas por fuerzas sísmicas o de viento del armazón hastial al techo o diafragma de techo. Estas tablas e información no sustituyen el flujo completo de análisis de cargas que debe llevar a cabo el diseñador estructural.
Examples of gable end frame web reinforcement to resist lateral loads applied perpendicular to the plane of the frame.
Vertical members with T- or L-Reinforcement
Scab reinforcement for structural gable end frame
Vertical member of Gable End Frame
T-Reinforcement
L-Reinforcement
Scab Reinforcement on one faceTruss member
7/16 OSB
Block sheathing edges within 4' of Gable Truss
Fasten OSB to framing @ 3" o.c. on edge, 6" o.c. in field with 8d nails2x4 SYP outrigger at 24" on center. Clip to Gable Top Chord with HB w/(10) 8d nails.
Block between outlookers. Fasten to Gable Top Chord w/ 10d Toe-nails @ 8" o.c.
Gable Top Chord
L-Reinforcement on Gable Verts as specified by Truss Manufacturer.Gable Truss
If vertical is not present, scab full height vertical from Bottom Chord to Top Chord w/(4) 10d nails each end. (TYP)
Clip end of Lateral Restraint to Gable Bottom Chord with (2) H2.5 w/(8) 8d nails.
Gable Bottom Chord. Fasten to top plate w/ 10d toe-nails @ 8" o.c.
Strap Gable Truss to stud wall with MSTA12 with (8) 10d nails @ 48" o.c.
2x4x8' SYP Lateral Restraint @ 48". Fas-tened to each truss w/ (2) 16d common nails.
2x4 No. 2 SYP X-bracing at mid-span and at 48" o.c. run back 8' from gable. Attach to gable and truss verticals w/(3) 16d nails.
SAMPLE
Example of balloon- framed gable end wall. Fireblocking not shown for clarity.
Figure A
Example of raked gable end wall (with scissors gable end frame)
El diseñador estructural puede decidir diseñar una pared con armazón de globo (balloon frame), lo cual elimina la necesidad de usar un armazón hastial (Imagen A). Si se utiliza un armazón hastial, tiene que coincidir con el perfil de las armaduras adyacentes para garantizar que la parte superior de la pared del fondo quede apuntalada por el diafragma del techo y esté en línea con este último (Imagen B).
¡ATENCIÓN! Si se usa un armazón hastial de cuerda inferior plana con armaduras adyacentes que tienen cuerdas inferiores inclinadas (Imagen C), se creará una bisagra en el punto de contacto entre la pared y el armazón que se encuentra por debajo del diafragma del techo. Esto está prohibido en algunos códigos de construcción y el diseñador estructural debe realizar diseños especiales de apuntalamiento de la pared del fondo.
Ejemplos de refuerzo de viguetas del armazón hastial para resistir car-gas laterales aplicadas de forma perpendicular al plano del armazón.
Example detail provided by a building designer, specifying gable end frame bracing and reinforcement.
Structural Building Components Association6300 Enterprise Lane • Madison, WI 53719
608-274-4849 • sbcindustry.com
SAMPLE
Balloon Framed Gable End Walls and Sloped Bottom Chord Gable End FramesParedes de Extrema Hastíales de Armazón Continua y Armazones Hastíales con Cuerdas Inferiores Pendientes
