Papers by Keyword: Short Column

Abstract: Bamboo scrimber is a promising engineered bamboo material in the construction sector due to its favourable mechanical and aesthetic properties. Although considerable research on mechanical properties has been conducted, there is a gap in the knowledge of slenderness limits for short columns of bamboo scrimber. Slenderness limits suggested in four testing and structural design standards that are commonly used for engineered bamboo have been critically analysed and compared to identify their relative shortcomings. From these standards, Eurocode 5 proposes a better limit while the others behave conservatively. Owing to the lack of a design standard for engineered bamboo, researchers abide by standards compiled for timber/engineered timber to predict the compressive response of intermediate and long columns. In addition to showing the limitations of these studies, a rational column equation has been derived with a modified Euler load that yields reasonable accuracy with respect to two experimental studies.

Abstract: An experimental study was carried out to investigate the behaviour of short column confined by waste plastic bags and nylon strips and findings of this study are presented in this paper. Eight reinforced concrete (RC) short columns were casted. Among them two specimens were named as control, while remaining six specimens were divided into three groups [two specimens for each group] based on different confinement techniques investigated in this study. In retrofitting technique 1 (RT-1), RC short columns were externally confined by full wrap of plastic bags, while in retrofitting techniques 2 (RT-2) and 3 (RT-3), confinement was provided to the short columns by stirrups of nylon and plastic bags with 25 mm clear spacing, respectively. The testing under compression loading was performed on UTM of 100T capacity. From the results obtained, seismic parameters such as ductility, fracture energy before peak and after peak, factor k* and load-displacement response were studied. The results indicated that RC short column confined by RT-1 (full wrap) gives better performance in terms of ductility and fracture energy after peak. Increase in the ductility of RT-1 specimen was about 25% as compared to the control one. Moreover, post-peak fracture energy exhibited by short column confined through techniques RT-1 and RT-2 was 132 and 125 N/mm as compared to control one with 14 N/mm of fracture energy. The experimental observations further indicated that the failure of control specimen was sudden showing high brittleness while the failure of confined specimens by RT-1 and RT-2 techniques was observed to be gradual giving some warning before final failure.

Abstract: For traditional ordinary concrete wall column prone to thermal bridges, posted outside the insulation board short life than the life of the building，in the glazed hollow bead of recycled concrete foundation with good thermal conductivity test and compressive strength of the proposed ,use glazed hollow bead of recycled concrete exterior wall column instead of the traditional ordinary concrete wall column ,and using the finite element software ANSYS simulation analysis the uniaxial compression of glazed hollow bead of recycled concrete short columns and ordinary concrete short columns. Comparative analysis showed the same intensity level glazed hollow bead of recycled concrete ultimate compressive bearing capacity of an analog value the same as ordinary concrete short columns. To validate the ANSYS simulation of concrete short columns under uniaxial compression condition .

Abstract: To study the ultimate bearing capacity of axial compression short column of double back-to-back C steel with gusset plates, the bearing capacity of seven short columns of this section type were analyzed by experiment and finite element analysis, the destroyed form of the composite columns were understood, the degree of influence of C steel type, plate thickness and plate spacing on mechanical performance of composite columns were got, some basis for the application of this type member in practical engineering were provided.

Abstract: Under the action of axial compression, it is difficult to deduce the capacity of concrete-filled rectangular steel tube (CFRST) short column in theory because of the complex constraining force between the steel tube and concrete. This paper uses two methods to study the axial bearing capacity of CFRST short column, the first method is to consider the main factors influencing the axial bearing capacity of CFRST column based on a great deal of experiments and use multiple linear regression method of mathematical statistics to obtain the formula of the axial bearing capacity of CFRST short column; the second method is to simulate the axial compression test of CFRST short column by using the powerful structure finite element analysis software ANSYS, and determine the axial bearing capacity of CFRST short column through 3D solid modeling, rational meshing and correct loading method. Those two methods provide new thoughts for forecasting the axial bearing capacity of CFRST short column.

Abstract: BFRP has excellent strength, durability, thermal properties and economic cost. To test seismic performance of short columns strengthened with BFRP. Low cyclic loading test was conducted on one comparative short column and two RC short columns strengthened with BFRP. The test shows that short columns warped by BFRP show excellent failure modes, shear capacity, ductility and energy dissipation. As a new fiber reinforced plastic, BFRP has a good prospect in the area of seismic strengthening for its low cost and comprehensive mechanical properties.

Abstract: This paper presents a new method of direct stress test in the core area of CFRP confined concrete short column by using cement-based piezoelectric sensor. The sensors are embedded in the core area of concrete short columns, dynamic fatigue tests are taken on the columns before and after CFRP reinforcement respectively. The results show that an obvious linear relation is found between sensor output signal and test input load, the slope of load-sensor signal curve of concrete short column is larger after CFRP reinforcement, the sensor signal peak is increased with the increase of the loading frequency, but the loading frequency is almost no effect on the increasing extent of the stress, the stresses in the core area of concrete short columns can be significantly improved after the columns reinforced by CFRP, the increment percentages are in the range of 5% ~ 20%.

Abstract: Concrete-filled steel tube structure is one of the important load-bearing systems of modern high-rise building.The research indicate that concrete-filled steel tube structure has a good static and seismic performance,and concrete-filled steel tubular component is always used as axial compression and compression-bending component.However,what about the mechanical behavior of this combinational structure (concrete-filled steel tubular columns with steel bone built-in) So there is a new type of special-shaped cross-section of composite structure,that is the T-shaped concrete-filled steel tubular columns with steel bone.The research about this structure is less throughout domestic and foreign.So the axial compressive experiments of six T-shaped concrete-filled steel tubular stub columns, five with and one without steel bone, were carried out. The effects of tube confining factor, bone indicator on the axial compressive behavior of the columns are analyzed. Experimental results indicate that the ultimate strength of the T-shaped steel tubular stub columns with steel bone increases, can be increased by 71.7%.And that the setting of steel bone improves the confinement of the concrete core, delays or even avoids the local buckling of the steel tube before the stress attains the yield strength. The ductility of the columns is also greatly increased.And at last in this paper, use of static equilibrium conditions and limit yield conditions,and in reference to literature[1],the calculation equation of compression capacity of this combinational column is derived.Moreover,calculation results according to the formula in this paper are in good agreement with the experimental results. The conclusions might be used as reference to structural design and plan.

Abstract: A comparative study is conducted on the seismic behaviors of five 1/2 scale recycled concrete short columns with 1.75 shear span ratios. The stirrup ratio in the specimens was changed from 0.4%, 0.9%, to 1.29% while the ratio of their longitudinal reinforcement was the same. Crossed reinforcing bars were set in two of the specimens. Cyclic loading test was carried out for the specimens under axial compression ratio 0.4. The stiffness and its degradation, load-carrying capacity, ductility, hysteretic behavior, energy dissipation and failure phenomena of each short column were analyzed. Results show that, with the increase of the stirrup ratio in the specimens, the shear failure of the specimens is getting lighter and lighter. And the load-carrying capacity, ductility, energy dissipation capacity are improved greatly, but the rate of the increase is tending to slow. Moreover, crossed reinforcing bars in the short columns are able to improve the seismic behavior. Recycled concrete can be used for structural columns with low axial compression ratio in earthquake area.

Abstract: This paper presents the experimental results of the wood columns externally strengthened with fiber reinforced polymer (FRP) subjected to axial compressive loading. In total, 14 square short wood columns were made, which were reinforced by FRP in two reinforcing arrangements. The main parameters studied in the test were (1) the strengthening materials, i.e. carbon FRP (CFRP), basalt FRP (BFRP) and aramid FRP (AFRP); (2) the reinforcing arrangements, i.e. the full wrapping of FRP and the partial reinforcing arrangement; (3) the layers of FRP sheets applied, i.e. one, two and three. The ultimate strength, load-axial displacements curves, load-strain relationships, and the failure modes of all the columns were presented. The test results show that both types of the reinforcing arrangements could increase the ultimate strength and stiffness of the columns tested greatly. The columns strengthened with two layers of FRP sheets gave higher load carrying capacities when compared to the columns strengthened with one or three layers of FRP sheets. The result confirms that the more layers of FRP sheets, the higher of load carrying capacity; however, the adverse results were shown when three layers of FRP sheets applied. Finally, the result also showed that the full wrapping reinforcing arrangement is more effective than the partial one in enhancing the stiffness.