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Xu H.,Southwest Jiaotong University | Yu Z.-X.,Southwest Jiaotong University | Zhao S.-C.,Southwest Jiaotong University | Zhao S.-C.,Key Laboratory of Seismic Engineering of Sichuan Province
Sichuan Daxue Xuebao (Gongcheng Kexue Ban)/Journal of Sichuan University (Engineering Science Edition) | Year: 2012

To overcome the difficulty in the convergence of hysteretic analysis on numerical calculation by available models for concrete, an incompatible D-P model was proposed to simulate concrete based on the classical Drucker-Prager(D-P for short) model with modified cap yield criterion. A large amount of trial calculation was implemented to reveal the rational range of incompatible parameters α and k. The proposed model was used to simulate the mechanical behavior of a reinforced concrete specimen under monotonic load at mid-span, as well as hysteretic behavior of a reinforced concrete specimen and a steel reinforced specimen under low cyclic loading separately. By comparing with the experimental results, the adaptability of the model was verified adequately, and the restoring force model of concrete specimen under low cyclic loading could be obtained through numerical calculation.


Zhang P.,Southwest Jiaotong University | Sun Y.,Southwest Jiaotong University | Sun Y.,Kobe University | Zhao S.,Southwest Jiaotong University | Zhao S.,Key Laboratory of Seismic Engineering of Sichuan Province
Advanced Materials Research | Year: 2011

Analytical study was conducted to investigate effect of friction dampers on vibration control of steel frame structures. The friction dampers installed in a ten-storey sample frame structure have two levels of fictional resistances. Unlike the conventional friction damper which has one frictional resistance, the friction dampers with variable resistances (VRFD) can apply two levels of frictional resistances, the lower resistance of which is attended to absorb the seismic energy by a moderate earthquake or a strong wind, and the higher one of which is expected to dissipate the seismic energy induced by a severe earthquake. The time-historey analytical results of the sample frame have indicated that the VRFD could not only mitigate the seismic response of the frame structure under a moderate earthquake more effectively than the conventional frictional damper, but also provide the same level of damping effect to the structure under severe earthquake as the conventional one. © (2011) Trans Tech Publications, Switzerland.


Zhang P.,Southwest Jiaotong University | Yu Z.,Southwest Jiaotong University | Sun Y.,Southwest Jiaotong University | Sun Y.,Kobe University | And 2 more authors.
Advanced Materials Research | Year: 2012

The shear-type friction damper using aluminum alloy as the friction material were designed and tested under cyclical loading to investigate the effect of the lap gap to the frictional performance. The test results indicated that the dampers with a lap gap could also absorb energy stably with the same hysteretic behavior as a general friction damper; the frictional force of the shear-type friction damper depended not only upon the bolts tension by the high-strength bolts that clamped the sliding steel plate but also strongly upon the scale of lap gap. The lap gap changed in a scale of 0.12mm only, the average sliding force has four times increase at a lower level of bolt tension, and a double effect to increasing sliding force at the higher level of bolt tension.


Xu H.,Southwest Jiaotong University | Lv L.,Southwest Jiaotong University | Zhibin Z.,Southwest Jiaotong University | Yu Z.,Southwest Jiaotong University | Yu Z.,Key Laboratory of Seismic Engineering of Sichuan Province
Proceedings of the 12th International Symposium on Structural Engineering, ISSE 2012 | Year: 2012

Rockfall disasters happen frequently in the western mountainous area, which seriously influences the safety of bridge structures. In order to investigate damage modes of the reinforced concrete column under the impact load of rockfall, a finite element model is established based on Holmquist-Johnson-Cook (HJC) damage constitutive model, and the energy principle is used to testify stability of the calculation results. Besides, a group of parameters, including impact height (h), impact velocity (v), elevation impact angle (α) and the rock diameter (d), is taken into consideration to research their effect on damage degree of the column. The calculation results indicate that the HJC constitutive model can simulate the behavior of concrete under impact load effectively and the damage mode and degree is mainly affected by impact kinetic energy.


Pan Y.,Southwest Jiaotong University | Pan Y.,Key Laboratory of Seismic Engineering of Sichuan Province | Cao S.,Nanjing Southeast University | Jing D.,Nanjing Southeast University | And 2 more authors.
Advanced Materials Research | Year: 2011

A total of 32 circular-section concrete columns confined by CFRP sheet were tested in uniaxial compression involved in different preload ratio, concrete strength and CFRP plies. The failure characteristic and mechanics behavior of confined concrete columns were presented, and the descending of the peak stress and strain of confined concrete due to preload were analyzed. The experimental results indicated that the confinement effect of CFRP was influenced by preload ratio observably. The second stiffness, the peak stress and strain declined with preload ratio ascending, and the extent developed with the enhancement of CFRP ply. © (2011) Trans Tech Publications, Switzerland.

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