Study on the Influence of Concrete Strength on the Dynamic Performance of Prestressed Steel-Concrete Composite Beams

2013 ◽  
Vol 838-841 ◽  
pp. 392-396
Author(s):  
Wei Xu ◽  
Jian Ming Wu ◽  
Rui Ya Xiao ◽  
Wei Xu

Through the finite element analysis, studies on mechanical performance of prestressed steel-concrete composite beams when it is undered the low reversed cyclic loading, based on constitutive model of elastic-plastic and consider nonlinear property of materials, it indicated good agreement with the experiment. Change concrete strength of composite beams and study hysteresis curve, energy dissipation and so on.Study found that with the improvement of concrete strength, the hysteresis loop of prestressed steel-concrete composite beams become plump, down by the load carrying capacity, energy dissipation ability were improved significantly.when the load upward, the load bearing capacity,energy dissipation have a small rise, but not obvious. Incresae the concrete strength is good for dynamic performance of prestressed steel-concrete composite on the whole.

2020 ◽  
pp. 136943322098166
Author(s):  
Weiwei Lin

In this study, straight composite steel-concrete beams were tested to investigate their mechanical performance under combined negative bending and torsional moments. Two specimens were used in this study, and different ratios between the applied negative bending and torsional moments were induced. Load and deflection relationships, strain development on the steel main girder and shear connectors (stud), and the slip development on the steel-concrete interface were recorded in the test and reported in this paper. The results indicate that increase of torsional moment will result in the significant decrease of the load-carrying capacities (e.g. yield load and ultimate load) of the specimens. It was also found that the normal strains of stud shear connectors in such beams are very large and non-negligible compared to their shear strains. In addition, the maximum interface slip was found occurring at around the 1/4 span, and the support conditions and serious crack of the concrete were considered to be the main causes. The research results obtained in this study can provide references for the design and analysis of steel-concrete composite beams subjected to the combined negative bending and torsional moments.


2014 ◽  
Vol 1079-1080 ◽  
pp. 177-182
Author(s):  
Shao Wu Zhang ◽  
Ying Chuan Chen ◽  
Geng Biao Zhang

In order to study the performance of concrete frame columns that reinforcedby assembleinclined web steel truss, with the same reciprocatinghorizontal displacement and different axialcompression.It canbe calculate the mechanical behavior of concrete frame columns and reinforced columns by using the finite element analysis software ABAQUS. Simulation analysis shows that the bearing capacity ofreinforced columnshas greatly increased andpresented a full hysteresis curve. The result shows that the reinforcement method of assemble inclined web steel truss can greatly improve the bearing capacity and ductility of the concrete frame column, and the axial compression is larger, the better the reinforcement effect.


2021 ◽  
Vol 2101 (1) ◽  
pp. 012059
Author(s):  
Z J Yang ◽  
X Li ◽  
G C Li ◽  
S C Peng

Abstract Hollow concrete-filled steel tubular (CFST) member is mainly adopted in power transmission and transformation structures, but when it is used in the superstructure with complex stress, the hollow CFST member has a low bearing capacity and is prone to brittle failure. To improve the mechanical performance of hollow CFST members, a new type of reinforced hollow high strength concrete-filled square steel tube (RHCFSST) was proposed, and its axial compression performance was researched. 18 finite element analysis (FEA) models of axially loaded RHCFSST stub columns were established through FEA software ABAQUS. The whole stress process of composite columns was studied, and parametric studies were carried out to analyze the mechanical performance of the member. Parameters of the steel strength, steel ratio, deformed bar and sandwich concrete strength were varied. Based on the simulation results, the stress process of members can be divided into four stages: elastic stage, elastoplastic stage, descending stage and gentle stage. With the increase of steel strength, steel ratio, the strength of sandwich concrete and the addition of deformed bars, the ultimate bearing capacity of members also increases. Additionally, the increment of those parameters will improve the ductility of the member, except for the sandwich concrete strength.


Author(s):  
Ashwin Padmanaban Iyer ◽  
Anne Goj ◽  
Omar K. Ahmed

This study provides a methodology that can be used to evaluate the dynamic performance of fast depressurization devices used in liquid-filled oil transformers. Liquid-filled transformers are susceptible to explosions due to internal arcing if the dielectric insulation fails. The internal arc vaporizes a portion of the liquid and generates a sudden pressure wave. The first peak of the pressure wave has been measured to be as high as 13 bars, with time durations on the order of milliseconds [1]. Transformer tanks have a typical static withstand limit of approximately 1 bar gauge [2]. It is thus imperative that the tank be depressurized before the static pressure reaches such a threshold. One industry-accepted Fast Depressurization System [3] used to depressurize transformers after an internal arc is based on a patented rupture disk design [4]. This study compares the dynamic performance of this disk to results from a successful test campaign using a rupture disk as the depressurization device. Limiting loading rate values from the test campaign are then used to comment on the effectiveness of the design. The evaluation methodology is based on Pressure-Impulse (P-I) curves. The P-I curve was generated by running a series of Implicit Dynamic analysis using Code_Aster [5]. This iterative process first required establishing a failure mode that is consistent with actual observed failure in the field and observable in the Finite Element Analysis (FEA) model. The criteria were then used in interpreting the response of the Rupture Disk to a series of different half-sine wave pulse loading of varying amplitudes and time-periods. The generated P-I curve was then compared to loading rates observed in the test campaign [1] as well as three other higher loading rates (1.28 times, 2 times, 3.8 times, and 10.25 times the reported experimental rate) to qualitatively assess the effectiveness of the design. Results indicated that disk functions extremely effectively as a Fast Depressurization System as also corroborated by the test campaign. Although this methodology is used for the rupture disk, it is expected that this methodology can be extended to compare the dynamic performance of other depressurization devices.


2011 ◽  
Vol 94-96 ◽  
pp. 220-224 ◽  
Author(s):  
Xi Guang Cui ◽  
Hai Dong Xu

Considering the strain rate then puts forward the modified uniaxial dynamic constitutive model related to strain rate in concrete-filled square steel tube and the modified calculation results match well with the experimental results. Based on the above conclusion, uniaxial compression performance finite element analysis with different strain rate among 10-5/s–10-3/s is completed, the results showed that strain rate can obviously change the dynamic performance of the concrete-filled square steel tube. Through the analysis of the influencing factors of the core concrete compressive strength, it is showed that with the increasing of the strain rate and the improving of concrete strength, the ultimate bearing capacity of concrete-filled square steel tube is higher and the ductility is reduced. With the increasing of stirrup ratio, ultimate bearing capacity is greater and the ductility is enhanced. With the sectional dimensions increasing, the ultimate bearing capacity is greater and the ductility is enhanced.


2011 ◽  
Vol 71-78 ◽  
pp. 4521-4524 ◽  
Author(s):  
Ji Gang Zhang ◽  
Yan Mei Liu ◽  
Yuan Feng Gao ◽  
Jian Han

Pall-typed dampers(PFD) have good energy dissipation, and shape memory alloy(SMA) brace has good super-elastic performance, so the PFD-SMA support system is put forward. Through the test study of PFD-SMA support system, analyze the influence to its hysteretic characteristic by preload force of Pall-typed frictional damper, the stiffness and length parameters of shape memory alloy support. The test results show that PFD-SMA support system s have good energy dissipation and good reposition due to its super-elastic performance, with pre-load force increase, its super-elastic performance acts better, its hysteretic curve show super-elastic performance too, and it verifies the correctness of the finite element analysis.


2014 ◽  
Vol 578-579 ◽  
pp. 695-698
Author(s):  
Xi Le Li ◽  
Li Hua Niu

Based on the model experiment on seismic behavior of a 1-span, 2-story concrete-filled rectangular steel tubal (CFRST) frame under lateral cyclic loads, a 3-D nonlinear finite element model of concrete-filled rectangular steel tubular frame is proposed in the paper. Compared with the experimental hysteresis curve, the computational results are found to be accurate, which shows that this model proposed in the paper can be applied in structure analysis of concrete-filled rectangular tubular frames. So the model was used in the finite element analysis of concrete-filled rectangular frame with different axial load level. Compared the computational displacement envelop curves, it concludes that the ductility and bearing capacity of CFRST frames reduces with the increasing axial load level.


2014 ◽  
Vol 501-504 ◽  
pp. 1609-1614
Author(s):  
Zhong Peng ◽  
Jun Huang ◽  
Shao Bin Dai ◽  
Ji Xiong Liu

3 medium thick-walled cold-formed steel top-and-seat angle joints were designed. The ABAQUS nonlinear finite element analysis on earthquake resistance behaviors of the joints were conducted under low cyclic loading. The results indicate that the failure processes and failure modes of 3 specimens are basically the same, the destruction of joints derive from buckling deformation of the top-and-seat angle and buckling of the steel beam flanges; the shapes of hysteresis curves of all specimens are obvious pinch together and present spindle, the displacement ductility factors are greater than 5.5, the equivalent viscous damping factors are greater than 0.158, all the specimens possess good energy dissipation capacity. The secant stiffness variations are almost similar, each specimen represents significant degradation. Increase the thickness of angle and diameter of high-strength bolt can improve the mechanical performance of the joints. Increase the bolt diameter, the ductility, energy dissipation capacity and initial stiffness enhance obviously, however, there is no apparent effect while increasing the thickness of angle.


2011 ◽  
Vol 308-310 ◽  
pp. 368-372
Author(s):  
Shou Wen Yao ◽  
Jian Li Lv ◽  
Qing Dong Peng

Dynamic performance is one of the most important factors in the product’s life. Transmission housing is one of the important components in vehicle, which has direct influence on the vehicle’s powertrain performance. Dynamic topology optimization can improve the product’s performance. The dynamic topology model is built, in which the density of elements are the design variables, the displacement of frequency response and volume are the constraints, and the objective is to maximize the first natural frequency of the housing. According to the result of optimization, the CAD model of housing is rebuilt and the finite element analysis of the new housing is done.The results show that both the static and dynamic performance are improved besides the mass reduction, namely, dynamic topology optimization can significantly improve the product’s performance.


2014 ◽  
Vol 488-489 ◽  
pp. 704-707
Author(s):  
Ying Wang ◽  
Miao Li ◽  
Jin Hua Xu ◽  
He Fan

Based on finite element analysis o f concrete filled steel tube beam-column joints under the single axial compression ratio and concrete strength, further research was done to analyze the seismic performance of concrete filled steel tube beam-column joints under different axial compression ratio and concrete strength. Beam-column joint which is connected by bolts with welding extended steel sheets at the beam root was analyzed. The results show that with the increase of axial compression ratio, strength and stiffness degradation of the joint accelerated gradually. Axial compression ratio at 0.3, 0.4 are appropriate values for joints specimen, load-displacement hysteresis curve of joint specimens is relatively plump and shows good seismic performance. Chance of concrete strength also had effect on seismic performance of joint specimen, but in contrast it is not so obviously.


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