Analysis of the Seismic Performance of a Two-Span Specially Shaped Column Frame

In traditional building construction, the structural columns restrict the design of the buildings and the layout of furniture, so the use of specially shaped columns came into being. The finite element model of a reinforced concrete framework using specially shaped columns was established by using the ABAQUS software. The effects of concrete strength, reinforcement ratio, and axial compression ratio on the seismic performance of the building incorporating such columns were studied. The numerical analysis was performed for a ten-frame structure with specially shaped columns under low reversed cyclic loading. The load-displacement curve, peak load, ductility coefficient, energy dissipation capacity, and stiffness degradation curve of the specially shaped column frame were obtained using the ABAQUS finite element software. The following three results were obtained from the investigation: First, when the strength of concrete in the specially shaped column frame structure was increased, the peak load increased, while the ductility and energy dissipation capacity weakened, which accelerated the stiffness degradation of the structure. Second, when the reinforcement ratio was increased in the specially shaped column frame structure, the peak load increased and the ductility and energy dissipation capacity also increased, which increased the stiffness of the structure. Third, when the axial compression ratio was increased in the structure, the peak load increased, while ductility and energy dissipation capacity reduced, which accelerated the degradation of structural stiffness.

Parametric Analysis on Collapse-resistance Performance of Reinforced-concrete Frame with Specially Shaped Columns Under Loss of a Corner Column

A finite element model is verified accurate enough to simulate the static test of one reinforced-concrete frame with specially shaped columns subjected to the loss of a ground corner column. As the frame sustained loads primarily depending on the beam resisting mechanism in the test, four related parameters, namely the height of beam section, rebar ratio of beam, rebar ratio of slab and limb length of specially shaped column are chosen for parametric analyses respectively. It is indicated that the collapse-resistance capacity remarkably increases with the increasing of the height of beam section and rebar ratio of the lower steel bars of beam. The increase of the rebar ratio of slab and upper steel bars of beam could enhance the stiffness and collapse-resistance capacity slightly. The lengthening of the limb of specially shaped column only increases the stiffness of the frame. According to an equivalent method, the rectangular column frame is obtained to compare collapse-resistance performance with the specially shaped column frame. It is concluded that the frame with specially shaped columns could maintain the equivalent collapse-resistance capacity while reduce the lateral stiffness compared with the rectangular column frame.

Experiment on Seismic Behavior of Frame with Specially Shaped Columns Used Wide Flange in the First Floor and General on the above

Studies show that the stiffness of the first floor column about concrete frame with general specially shaped column is insufficient, the column bottom will be compression damaged easily, the author advice using wide flange specially shaped column in the first floor to enhance the stiffness, so this paper designed a 1/3 scale RC frame with specially shaped columns used wide flange in the first floor and general on the above, furthermore the height of the first floor was higher than other floors. Then low frequency cyclic loading was experimented to the concrete frame, the seismic behavior of this kind frame such as damage characteristic, failure mechanism, bearing capacity, deformation capacity, hysteresis curve and storey drift were researched. It was shown that the seismic behavior of this structure was generally good, the method that changed the first floor to wide flange specially shaped column for concrete frame with specially shaped columns could enhance the stiffness of the first floor clearly, meanwhile the seismic behavior of the frame were improved.

Numerical Analysis on a New Type Cross-Shaped Frame Joint of Steel Reinforced Concrete Special-Shaped Column

In order to facilitate the construction, this paper presents a new type of cross-shaped frame joint of steel reinforced concrete special-shaped column, and the cross-shaped frame joint of new type of specially-shaped column is the regular concrete joint which is added acre steel-shaped steel. Numerical analysis is conducted on a regular concrete cross-shaped frame joint of specially-shaped column of a frame structure in the region with intensity 8 of Chinese intensity scale, and the joint of corresponding new type of specially-shaped column of the same structure, to obtain the conclusion that when the new type of cross-shaped frame joint of steel reinforced concrete special-shaped column is 6% in steel ratio, the ultimate bearing capacity of joint relative to the RC nodes can improve 34.5%.which shows that the cross-shaped frame joint of new type of specially-shaped column can not only has the advantages of convenient construction, accelerate the construction speed, and the shear capacity also has safeguard.

Study on Mechanical Performance of the End-Plate Connection Joint between H-Section Beam and Closed Specially-Shaped Column

This paper brings forward a new kind of specially-shaped column and its end-plate connection joint with H-section beam. The static loading and cyclic loading simulation tests of the joint are carried out using the finite element software. Under static load, the moment-rotation curves with different parameters are obtained, and then the effects of those parameters on the initial stiffness and the ultimate moment and the stress distribution of key positions of the joint are discussed; under cyclic load, the moment-rotation hysteretic curves are obtained and mechanical behaviors of the basic test specimen are comprehensively analyzed. The results indicate that the joint possesses not only reasonably high initial stiffness and ultimate capacity, but also excellent ductility and energy-dissipation capacity.

Effect of Axial Compression Ratio on Ductility and Bearing Capacity of Specially Shaped Columns with HRB500 Reinforcement

Four specially shaped columns with HRB500 reinforcement were tested under low cyclic loading. The hysteretic curve, yield load, ultimate load, displacement ductility and rigidity degradation were compared in order to research the effect of axial compression ratio on ductility and bearing capacity of specially shaped column with HRB500 reinforcement. It is shown that the axial compression ratio has greater influence on ductility and bearing capacity. With the increase of axial compression ratio, the bearing capacity of HRB500 reinforcement concrete specially shaped column can be enhanced while the deformation capacity becomes worse. The hysteretic characteristic of specially shaped columns with HRB500 reinforcement is improved and the stiffness degeneration becomes slow with the decrease of axial compression ratio.

Experimental Research on Seismic Behavior of Interior Joints of Specially Shaped Columns Reinforced by Fiber

Based on the low cyclic loading experiments on three interior joints with specially shaped columns, in which one of them was reinforced by polypropylene fiber in the core zone of joint, another steel fiber, the other was not reinforced, the authors compare the results in terms of damage characteristic, bearing capacity, displacement and ductility, hysteretic curve of the moment-rotation, rigidity degradation and energy dissipation. It is shown that seismic behavior of specially shaped column interior joints reinforced by fiber is improved significantly. The interior joint of specially shaped column reinforced by polypropylene fiber has a better damage characteristic and energy dissipation while that by steel fiber shows a higher yield load and bearing capacity.