Analysis on Extension Length of Shape Steel in Transfer Columns of SRC–RC Hybrid Structures

Kai Wu,Jianyang Xue,Yang Nan,Hong-tie Zhao 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.3

Seismic performance of SRC–RC transfer column was analyzed based on the experiment of 16 transfer columns specimens under low cyclic reversed loading, which mainly focus on the extension length of shape steel. Analysis of ductility, bearing capacity, energy dissipation capacity and degeneration ratio of strength were completed. Displacement ductility promotes at fi rst and then reduces with increasing of extension length of shape steel, reaching the peak value when extension length gets close to three fi fths of column height. Extension length of shape steel has little eff ect on bearing capacity, while energy dissipation capacity of transfer columns is infl uenced by many factors. Three fi fths of column height is the rational extension length of shape steel, of which specimens have advanced in energy dissipation, good stability of stiff ness and strength. The bond performance between concrete and shape steel decreases with the increasing of extension length of shape steel, and hence the stability of strength decreases. Minimum extension length of shape steel was confi rmed and the calculation method was proposed, which is mainly used to ensure the bend yielding of shape steel at bottom section. Moment at the truncation section leads to pull-out eff ect of steel bars, which enhances with increasing of the moment and section ratio of shape steel. Contrafl exure point is at three fi fths of column height. If the shape steel extends to contrafl exure point, moment of steel truncation section will reach minimum. So the reduce the concrete damage with better deformation ability and mechanical behavior of transfer column.

Experimental study on shear damage and lateral stiffness of transfer column in SRC-RC hybrid structure

Kai Wu,Jiangpeng Zhai,Jianyang Xue,Fangyuan Xu,Hongtie Zhao 사단법인 한국계산역학회 2019 Computers and Concrete, An International Journal Vol.23 No.5

A low-cycle loading experiment of 16 transfer column specimens was conducted to study the influence of parameters, likes the extension length of shape steel, the ratio of shape steel, the axial compression ratio and the volumetric ratio of stirrups, on the shear distribution between steel and concrete, the concrete damage state and the degradation of lateral stiffness. Shear force of shape steel reacted at the core area of concrete section and led to tension effect which accelerated the damage of concrete. At the same time, the damage of concrete diminished its shear capacity and resulted in the shear enlargement of shape steel. The interplay between concrete damage and shear force of shape steel ultimately made for the failures of transfer columns. With the increase of extension length, the lateral stiffness first increases and then decreases, but the stiffness degradation gets faster; With the increase of steel ratio, the lateral stiffness remains the same, but the degradation gets faster; With the increase of the axial compression ratio, the lateral stiffness increases, and the degradation is more significant. Using more stirrups can effectively restrain the development of cracks and increase the lateral stiffness at the yielding point. Also, a formula for calculating the yielding lateral stiffness is obtained by a regression analysis of the test data.

Experimental research on seismic behavior of SRC-RC transfer columns

Kai Wu,Jianyang Xue,Yang Nan,Hongtie Zhao 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.1

It was found that the lateral stiffness changes obvious at the transfer position of the section configuration from SRC to RC. This particular behavior leads to that the transfer columns become as the important elements in SRC-RC hybrid structures. A comprehensive study was conducted to investigate the seismic behavior of SRC-RC transfer columns based on a low cyclic loading test of 16 transfer columns compared with 1 RC column. Test results shows three failure modes for transfer columns, which are shear failure, bond failure and bend failure. Its seismic behavior was completely analyzed about the failure mode, hysteretic and skeleton curves, bearing capacity deformation ability, stiffness degradation and energy dissipation. It is further determined that displacement ductility coefficient of transfer columns changes from 1.97 to 5.99. The stiffness of transfer columns are at the interval of SRC and RC, and hence transfer columns can play the role of transition from SRC to RC. All specimens show similar discipline of stiffness degradation and the process can be divided into three parts. Some specimens of transfer column lose bearing capacity swiftly after shear cracking and showed weak energy dissipation ability, but the others show better ability of energy dissipation than RC column.

Dynamic experimental study on single and double beam-column joints in steel traditional-style buildings

Xue, Jianyang,Qi, Liangjie,Yang, Kun,Wu, Zhanjing Techno-Press 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.5

In order to study the failure mode and seismic behavior of the interior-joint in steel traditional-style buildings, a single beam-column joint and a double beam-column joint were produced according to the relevant building criterion of ancient architectural buildings and the engineering instances, and the dynamic horizontal loading test was conducted by controlling the displacement of the column top and the peak acceleration of the actuator. The failure process of the specimens was observed, the bearing capacity, ductility, energy dissipation capacity, strength and stiffness degradation of the specimens were analyzed by the load-displacement hysteresis curve and backbone curve. The results show that the beam end plastic hinge area deformed obviously during the loading process, and tearing fracture of the base metal at top and bottom flange of beam occurred. The hysteresis curves of the specimens are both spindle-shaped and plump. The ultimate loads of the single beam-column joint and double beam-column joint are 48.65 kN and 70.60 kN respectively, and the equivalent viscous damping coefficients are more than 0.2 when destroyed, which shows the two specimens have great energy dissipation capacity. In addition, the stiffness, bearing capacity and energy dissipation capacity of the double beam-column joint are significantly better than that of the single beam-column joint. The ductility coefficients of the single beam-column joint and double beam-column joint are 1.81 and 1.92, respectively. The cracks grow fast when subjected to dynamic loading, and the strength and stiffness degradation is also degenerated quickly.

Protection of chickens against infectious bronchitis virus with a multivalent DNA vaccine and boosting with an inactivated vaccine

Fang Yan,Zhong Li,Yongting Hu,Jianyang Qiu,Wenxin Lei,Wenhui Ji,Xuying Li,Qian Wu,Xiumin shi,Yujun Zhao 대한수의학회 2013 Journal of Veterinary Science Vol.14 No.1

The protective efficacy of DNA plasmids encoding avian infectious bronchitis virus (IBV) S1, N, or M protein was investigated in chickens. Chickens were inoculated monovalently (with plasmid pVAX1-16S1, pVAX1-16M, or pVAX1-16N alone) or multivalently (combination of the three different plasmids, pVAX1-16S1/M/N). A prime-boost immunization protocol against IBV was developed. Chickens were immunized with the multivalent DNA vaccine twice and then boosted with an inactivated vaccine once. Antibody titers of the chickens immunized with pVAX1-16S1/M/N were much higher than those of the monovalent groups (p < 0.01). A protective rate up to 90% was observed in the pVAX1-16S1/M/N group. The serum antibody titers in the prime-boost birds were significantly higher than those of the multivalent DNA vaccine group (p < 0.01) but not significantly different compared to the inactivated vaccine group at 49 days of age. Additionally, the prime-boost group also showed the highest level of IBV-specific cellular proliferation compared to the monovalent groups (p < 0.01)but no significant difference was found compared to the multivalent DNA vaccine group, and the prime-boost group completely protected from followed viral challenge.

Polyacrylonitrile mesoporous composite membranes with high separation efficiency prepared by fast freeze-extraction process

Ruixue Lv,Faizal Soyekwo,Qiugen Zhang,Runsheng Gao,Jianyang Wu,Yan Qu,Aimei Zhu,Qinglin Liu 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.49 No.-

Polymer mesoporous membranes are widely employed in many membrane processes includingultrafiltration and dialysis, and become more crucial with increasing demand in chemical and lifefields. Here we report a highly-efficient polymer membrane with sub-5 nm pores and highflux frompolyacrylonitrile (PAN) nanoparticles produced from dilute PAN solution via fast freeze-extractionprocess. The25 nm-size PAN nanoparticles forming brad-like chains are dispersed in ethanol solutionand used to prepare the membrane byfiltration-assisted assembly method across a macroporoussupport. Effects of solvents and usage of PAN on membrane formation is studied in detail. The resultantmembranes comprise of the nanoparticles stacked on the support to form a mesoporous separation layerwith a controllable thickness and a cut-off of below 5 nm. They exhibit excellent separation performancesin ultrafiltration of protein and nanoparticle solutions. Typically, the membrane with 94.6% rejection of5 nm gold nanoparticles has a pure waterflux of 823 L m 1 h 1 bar 1 and perfect rejection for ferritinmolecules and 10 nm gold nanoparticles. The newly developed membranes should have wide applicationin chemical, environment and lifefields.