SEISMIC BEHAVIOR OF BEAM COLUMN JOINTS IN

REINFORCED CONCRETE MOMENT RESISTING

FRAMES

PAVANKUMAR N4BW13CSE082ND SEMESTER M.TECHSTRUCTURAL ENGINEERING

GUIDE-Mr. CHETHAN GOWDA R K

Introduction to Beam-Column Joint

Types & Importance of Beam-Column Joint

Seismic Behaviour of Joints

Reinforcing Beam-column Joints

Provision for Horizontal ties in beams

Anchorage of beam bars

Exterior joint

Interior Joints

In RC buildings, portions of columnsthat are common to beams at theirintersections are called beam-column joints.

Since their constituent materials havelimited strengths, the joints have limitedforce carrying capacity.

When forces larger than these are appliedduring earthquakes, joints are severelydamaged.

Repairing damaged joints is difficult, and sodamage must be avoided. Thus, beam-columnjoints must be designed to resistearthquake effects.

Under earthquake shaking, the beams adjoininga joint are subjected to moments in the same(clockwise or counter-clockwise) direction .

Under these moments, the top bars in thebeam-column joint are pulled in one directionand the bottom ones in the opposite direction .

If the column is not wide enough or if thestrength of concrete in the joint is low,there is insufficient grip of concrete onthe steel bars.

In such circumstances, the bar slips insidethe joint region, and beams loose theircapacity to carry load.

one diagonal length of the joint elongates andthe other compresses . If the column cross-sectional size is insufficient, the concrete inthe joint develops diagonal cracks.

Diagonal cracking & crushing of concrete canbe prevented in Joints.

Mostly, for this large column size is the mosteffective.

Another way is providing steel ties alsoknown as stirrups.

Reinforcing the beam column joint

Reference

Seismic Behavior of Beam Column Joints in Reinforced Concrete Moment Resisting Frames, Document No. :: IITK-GSDMA-EQ31-V1.0 Final Report :: A - Earthquake Codes IITK-GSDMA Project on Building Codes

How do beam-column joints in RC buildings Resist Earthquakes? IITK-BMTPC Earthquake tips20

Thank you