BRACED FRAME SRUCTURE WITH SHEAR CORE

• Shear walls: To resist the lateral load caused by wind & earthquake

• Relatively thin: height/width

• The assembly of shear walls is known as “coupled shear wall”

• Belt trusses distribute the tensile and compressive force to the large no. of exterior trusses

BRACED CORE STRUCTURE:

• Shear Resisting core

• Minimized possibility of torsion due to lateral load

• May contain one or more cores

Connected by outriggers to provide column free space

• Out rigger generally form of steel trusses or reinforced concrete

• connect core to the peripheral columns, reduce the overturning moment and lateral drift in the building.

TUBE STRUCTURE:

• Utilize entire building to resist lateral loads.

• Outer frame: closely spaced columns rigidly connected to deep spandrel beams.

• Loads are transferred by external frame

Exterior column spacing 5ft to 15 ft (1.5 m-4.5 m)

Spandrel beam depth 24 in-48 inch (600-1200mm)

Shear lag reduced by use of belt truss placed on exterior wall panels.

Belt truss used to equalize tension and compression forces due to shear lag.

TUBE IN TUBE STRUCTURE:

Stiffness of framed tube is improved by using structural core.

• Resist gravity as well as lateral loads.

• Floor diaphragms tie the exterior and interior tube together

• Allowing two tubes to resist as one unit

BRACED TUBE STRUCTURE:

Framed tube + Diagonals = braced tube

• Diagonal braces and spandrel beams give wall like rigidity against lateral loads

• Stiffening the parameter frames overcomes the shear lag problem faced by framed tube.