Check capacity/draw interection diagram of a column and design the column for eccentricity in ETABS
6.3 هزار بار بازدید -
3 سال پیش
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Hello dears,Today in this video
Hello dears,
Today in this video I will show you how to determine the capacity of a column for different eccentricity value. The type of failure for a column depends on the value of eccentricity e, which in turn is defined by the load analysis of the building or other structure.
In the region of compression failure the larger the axial load Pn, the smaller the moment Mn that the section is able to sustain before failing. However, in the region of tension failure, the reverse is true; the larger the axial load, the larger the simultaneous moment capacity. This is easily understood. In the compression failure region, failure occurs through overstraining of the concrete. The larger the concrete compressive strain caused by the axial load alone, the smaller the margin of additional strain available for the added compression caused by bending. On the other hand, in the tension failure region, yielding of the steel initiates failure. If the member is loaded in simple bending to the point at which yielding begins in the tension steel, and if an axial compression load is then added, the steel compressive stresses caused by this load will be superimposed on the previous tensile stresses. This reduces the total steel stress to a value below its yield strength.
Consequently, an additional moment can now be sustained of such magnitude that the combination of the steel stress from the axial load and the increased moment again reaches the yield strength.
The typical shape of a column interaction diagram has important design implications. In the range of tension failure, a reduction in axial load may
produce failure for a given moment. When performing a frame analysis, the designer must consider all combinations of loading that may occur, including the combination that produces minimum axial load paired with a moment because the combined loading may place the column in the tension failure range. Within this range, only the compressive load that is certain to be present should be used to calculate the capacity of the column subject to the given moment.
Today in this video I will show you how to determine the capacity of a column for different eccentricity value. The type of failure for a column depends on the value of eccentricity e, which in turn is defined by the load analysis of the building or other structure.
In the region of compression failure the larger the axial load Pn, the smaller the moment Mn that the section is able to sustain before failing. However, in the region of tension failure, the reverse is true; the larger the axial load, the larger the simultaneous moment capacity. This is easily understood. In the compression failure region, failure occurs through overstraining of the concrete. The larger the concrete compressive strain caused by the axial load alone, the smaller the margin of additional strain available for the added compression caused by bending. On the other hand, in the tension failure region, yielding of the steel initiates failure. If the member is loaded in simple bending to the point at which yielding begins in the tension steel, and if an axial compression load is then added, the steel compressive stresses caused by this load will be superimposed on the previous tensile stresses. This reduces the total steel stress to a value below its yield strength.
Consequently, an additional moment can now be sustained of such magnitude that the combination of the steel stress from the axial load and the increased moment again reaches the yield strength.
The typical shape of a column interaction diagram has important design implications. In the range of tension failure, a reduction in axial load may
produce failure for a given moment. When performing a frame analysis, the designer must consider all combinations of loading that may occur, including the combination that produces minimum axial load paired with a moment because the combined loading may place the column in the tension failure range. Within this range, only the compressive load that is certain to be present should be used to calculate the capacity of the column subject to the given moment.
3 سال پیش
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