Thin-walled square steel tube regeneration mixed column under axial compression and Experimental study on seismic
Abstract: Recycled Concrete mixing components is an effective way of recycling waste concrete, and has broad application prospects. For the further expansion of the concrete recycled in the form of the mixed components, to improve their theoretical system, and application to lay the experimental and theoretical basis for concrete recycled mixed components, carried out the following: 18 regeneration of mixed concrete cube specimen under uniaxial pipeline compression test to analyze the mixing ratio of waste concrete, the old and new concrete strength and poor regeneration of mixed concrete compressive strength and stress - strain curves; proposal gives renewable hybrid combination of concrete strength formula. The results showed that:
Situ strength of concrete with waste concrete similar to (1) a mixture of waste concrete on the regeneration of mixed concrete compressive strength in less than 33% did not show a clear regularity; in-situ concrete strength significantly greater than the abandoned concrete, recycled mixed The compressive strength of concrete is reduced as the mixing ratio of waste concrete.
(2) regeneration of mixed concrete, the non-dimensional stress - strain curve with in-situ concrete is essentially similar, but relatively more gentle decline of the former Advance.
(3) using a linear combination formula renewable mixed concrete compressive strength with good engineering precision. 16 renewable hybrid stub columns of thin-walled square steel tube axis pressure test to study the mixing ratio of waste concrete, old and new concrete strength, the pipe wall thickness and other factors on the specimen under axial compression performance; based on a combination of old and new concrete strength, compared to analysis of the related formula pre-effectiveness of the test pieces under axial compression bearing capacity. The results show that:
(1) compared with full-situ thin-walled square steel tube concrete columns, thin-walled square steel tube regeneration of mixed short columns of steel yield earlier, waste concrete mixing ratio the greater the steel tube yield the sooner; (2) thin-walled square steel tube regeneration of mixed short columns under axial compression bearing capacity of the overall showing a trend to decrease than increase with the mixture of waste concrete, to reduce the regeneration of magnitude greater than the thin-walled circular steel hybrid stub columns; but when new, the old concrete compressive strength similar to the mixing ratio by 20%? changes in the range of 33% limited impact on the regeneration of mixed short columns under axial compression load on the thin-walled square steel tube;
(3) To enable the regeneration of mixed short columns with similar security with full-situ short columns Heavy Wall Steel Pipe, it is recommended that the adjustment factor calculated according to current design standards, thin-walled square steel tube regenerative hybrid stub columns under axial compression load multiplied by 0.9. 15 thin-walled square steel tube regeneration mixed column in the given regular axis force and the level of reciprocating loads seismic experiment investigated the waste concrete mixing than, pipe wall thickness, shaft pressure ratio and other parameters specimen seismic performance; based on old and new The combination of strength of the concrete, according to the design standards of the domestic and foreign steel concrete structure and fiber based on ABAQUS beam element numerical model, the horizontal bearing capacity of the specimen were calculated and analyzed. Studies have shown that: (1) waste concrete mixing ratio between 0 ~ 40% change on the specimen initial lateral stiffness, steel local buckling failure displacement, negative stiffness behavior, the equivalent viscous damping, hysteresis curve limited impact on the shape, but the regeneration of horizontal bearing capacity of the mixed columns in general lower than the full-situ column;
(2) when the pipe wall thickness between 1.78mm ~ 5.5mm, with the increase in pipe wall thickness of the specimen did not show better deformation capacity;
(3) in the pipe wall thickness of only 1.78mm (thickness ratio of 168.5 seamless pipe), the axial compression than the destruction of 0.4 recycled mixed column displacement angle up to 1/35, to meet the limits of the displacement angle between the relevant layer of the current seismic code requirements ; (4) use of the existing standard to calculate the horizontal bearing capacity of renewable mixed column of thin-walled square steel tube available considerable security and full-situ column; (5) cross-sectional area and the amount of steel at the same time, thin-walled square steel tube regeneration of mixed column seismic performance better than the reinforced concrete column.
Key words: thin-walled square steel tubes recycled cement mixed columns under axial compression seismic performance
[Degree-granting units: South China University of
[Degree levels: Master
[Degree-granting Year: 2011
【Key Words】: TU398.9