Concrete filled steel column (CFSC)

The CFSC system has many advantages compared with the ordinary steel or the reinforced concrete system. One of the main advantages is the interaction between the steel column and concrete, local buckling of the steel column is delayed by the restraint of the concrete and the strength of concrete is increased by the confining effect of the steel column.

The CFSC column system has many advantages compared with ordinary steel or reinforced concrete systems. Interaction between steel column and concrete: Local buckling of the steel column is delayed and the strength deterioration after the local buckling is moderated, both due to the restraining effect of the concrete. On the other hand, the strength of the concrete is increased due to the confining effect provided by the steel column. Drying shrinkage and creep of the concrete are much smaller than in ordinary reinforced concrete.

The steel ratio in the CFSC cross section is much large than in reinforced concrete and concrete-encased steel cross sections. The steel of the CFSC section is well plasticized under bending because it is located most outside the section.

Labor for forms and reinforcing bars is omitted, and concrete casting is done by tremie or pump-up method. This efficiency leads to a cleaner construction site and a reduction in manpower, construction cost, and project length.

Concrete improves fire resistance so that fireproof material can be reduced or omitted.

Because of the merits listed above, better cost performance is obtained by replacing a steel structure with a CFSC structure.

The environmental burden can be reduced by omitting the form work and by reusing steel column and using –quality concrete with recycled aggregates.

1. The concrete filled column system has many advantages compared with ordinary steel or reinforced concrete systems. The main advantages are listed below:

2. Interaction between steel tube and concrete: Local buckling of the steel tube is delayed, and the strength deterioration after the local buckling is moderated, both due to the restraining effect of the concrete. On the other hand, the strength of the concrete is increased due to the confining effect provided by the steel tube, and the strength deterioration is not very severe, because concrete spalling is prevented by the tube. Drying shrinkage and creep of the concrete are much smaller than in ordinary reinforced concrete.

3.Cross-sectional properties: The steel ratio in the CFST cross section is much larger than in reinforced concrete and concrete-encased steel cross sections. The steel of the CFST section is well plastified under bending because it is located most outside the section.

4. Construction efficiency: Labor for forms and reinforcing bars is omitted, and concrete casting is done by Tremie tube or the pump-up method. This efficiency leads to a cleaner construction site and a reduction in manpower, construction cost, and project length.

5. Compared with the hollow steel sections, concrete filled steel sections will have a higher fire resistance, and the need less fire proof material around the steel tubes, because concrete has a larger thermal capacity than air which is enclosed in the hollow steel tubes. Even if the sustained loads carried by steel are decreased by heat, the column will not be crushed during the fire if the columns are designed to sustain the dead and live loads only by their concrete cores. So the structures will not surer great damage. Concrete improves fire resistance so that fire proof can be omitted interaction b/w steel tube and concrete: Local buckling of the steel tube is delayed, and the strength deterioration after the local buckling is moderated, both due to the restraining effect of the concrete.

6. Significant economic advantages over either pure structural steel or reinforced concrete alternatives.

7.Identical cross sections with different load and moment resistances can be produced by varying steel thickness, the concrete strength and reinforcement. This allows the outer dimensions of a column to be held constant over a number of floors in a building, thus simplifying the construction and architectural detailing.

8. Higher strength and stiffness compared with RC columns of the same materials properties. Cross section properties: Steel ratio into CFST is much larger than in RC sections. The steel of CFST sections is well plastified under bending because it is located most outside the sections.

9. Cost performance: Cost effective when we compared to steel structure because of composite effect (steel and concrete).

10.Environmental: Form work can be reduced so that production of steel will be less and using high quality concrete with recycled aggregates.

Concrete filled steel column (CFSC)

The CFSC system has many advantages compared with the ordinary steel or the reinforced concrete system. One of the main advantages is the interaction between the steel column and concrete, local buckling of the steel column is delayed by the restraint of the concrete and the strength of concrete is increased by the confining effect of the steel column.

The CFSC column system has many advantages compared with ordinary steel or reinforced concrete systems. Interaction between steel column and concrete: Local buckling of the steel column is delayed and the strength deterioration after the local buckling is moderated, both due to the restraining effect of the concrete. On the other hand, the strength of the concrete is increased due to the confining effect provided by the steel column. Drying shrinkage and creep of the concrete are much smaller than in ordinary reinforced concrete.

The steel ratio in the CFSC cross section is much large than in reinforced concrete and concrete-encased steel cross sections. The steel of the CFSC section is well plasticized under bending because it is located most outside the section.

Labor for forms and reinforcing bars is omitted, and concrete casting is done by tremie or pump-up method. This efficiency leads to a cleaner construction site and a reduction in manpower, construction cost, and project length.

Concrete improves fire resistance so that fireproof material can be reduced or omitted.

Because of the merits listed above, better cost performance is obtained by replacing a steel structure with a CFSC structure.

The environmental burden can be reduced by omitting the form work and by reusing steel column and using –quality concrete with recycled aggregates.

1. The concrete filled column system has many advantages compared with ordinary steel or reinforced concrete systems. The main advantages are listed below:

2. Interaction between steel tube and concrete: Local buckling of the steel tube is delayed, and the strength deterioration after the local buckling is moderated, both due to the restraining effect of the concrete. On the other hand, the strength of the concrete is increased due to the confining effect provided by the steel tube, and the strength deterioration is not very severe, because concrete spalling is prevented by the tube. Drying shrinkage and creep of the concrete are much smaller than in ordinary reinforced concrete.

3.Cross-sectional properties: The steel ratio in the CFST cross section is much larger than in reinforced concrete and concrete-encased steel cross sections. The steel of the CFST section is well plastified under bending because it is located most outside the section.

4. Construction efficiency: Labor for forms and reinforcing bars is omitted, and concrete casting is done by Tremie tube or the pump-up method. This efficiency leads to a cleaner construction site and a reduction in manpower, construction cost, and project length.

5. Compared with the hollow steel sections, concrete filled steel sections will have a higher fire resistance, and the need less fire proof material around the steel tubes, because concrete has a larger thermal capacity than air which is enclosed in the hollow steel tubes. Even if the sustained loads carried by steel are decreased by heat, the column will not be crushed during the fire if the columns are designed to sustain the dead and live loads only by their concrete cores. So the structures will not surer great damage. Concrete improves fire resistance so that fire proof can be omitted interaction b/w steel tube and concrete: Local buckling of the steel tube is delayed, and the strength deterioration after the local buckling is moderated, both due to the restraining effect of the concrete.

6. Significant economic advantages over either pure structural steel or reinforced concrete alternatives.

7.Identical cross sections with different load and moment resistances can be produced by varying steel thickness, the concrete strength and reinforcement. This allows the outer dimensions of a column to be held constant over a number of floors in a building, thus simplifying the construction and architectural detailing.

8. Higher strength and stiffness compared with RC columns of the same materials properties. Cross section properties: Steel ratio into CFST is much larger than in RC sections. The steel of CFST sections is well plastified under bending because it is located most outside the sections.

9. Cost performance: Cost effective when we compared to steel structure because of composite effect (steel and concrete).

10.Environmental: Form work can be reduced so that production of steel will be less and using high quality concrete with recycled aggregates.