The Effects of the Rubber Bearing on the Seismic Performance of the Aqueduct-Water Coupling Structure

2013 ◽  
Vol 275-277 ◽  
pp. 1370-1373
Author(s):  
Qiu Hua Duan ◽  
Dan Dan Zeng ◽  
Lu Feng Yang

Rubber bearings are widely used in bridge structures. The aqueduct structures are water bridges, so rubber bearings are often set at the end of the aqueducts. Rubber bearing cannot solve the problems such as temperature stress and supporting inhomogeneous settlement, but also play role of isolation damping. This paper mainly studies on the effects of the water-depth with changing rubber bearing on the seismic performance of the aqueduct-water coupling structure by numerical analysis.

Author(s):  
Naito Nobuyuki ◽  
Park Kyeonghoon ◽  
Mazda Taiji ◽  
Uno Hiroshige ◽  
Kawakami Masahide

The characteristics of the seismic bearing change depending on various factors. When an earthquake occurs, the behavior of the bridge may differ from the values expected in the structural design. The shear deformation of the seismic bearing may increase, but it is difficult to reach the fracturede formation. This paper studied the effect of the stiffness due to various dependency and durability on Lead Rubber Bearings (LRB) and the over strength of bridge piers on the bearing behavior when an earthquake occurred. As a result, if the stiffness of LRB reduces within the criteria, seismic performance can be expected safety even if the shear strain designed in the current design is greater than the allowable shear strain. The reason is that the hardening phenomenon in the high strain region of the laminated rubber bearing suppresses the displacement. Also, since the seismic bridges with over strength of the piers have come near elastic behavior when an earthquake occurs, shear strain is easy to be large.


2021 ◽  
pp. 1-14
Author(s):  
Deng Pan ◽  
Tao Zhang

The stability of bridges in the face of earthquake hazards has always been the focus of construction engineering. At present, a large number of bridge construction has begun to use isolation rubber bearings to increase the seismic capacity of bridges. However, in the face of high-intensity earthquake disasters, the seismic performance of the bridge is gradually unable to meet, the main reason is the lack of relevant research on the seismic performance of the bridge in high seismic intensity area. Therefore, this study will explore the changes of the bridge in the face of high-strength earthquake, and try to use high damping rubber bearings for the isolation design of the bridge. By establishing the finite element model of continuous bridge combined with isolation rubber bearing, the numerical calculation of bridge element is carried out on this basis, and the isolation effect of isolation rubber bearing is analyzed. The results show that the compression resistance and shear resistance of the isolated rubber bearing are strong. Under the influence of different seismic waves, the maximum displacement of the bearing is 0.131 m and the maximum horizontal force is 389.6 kN, which are lower than the allowable value of the bridge, and the overall seismic performance of the bridge has been significantly improved, which can play a good theoretical support in the construction of continuous bridges in high seismic intensity areas.


2019 ◽  
Vol 3 (Special Issue on First SACEE'19) ◽  
pp. 199-206
Author(s):  
Bertha Olmos ◽  
José Jara ◽  
José Luis Fabián

This paper investigates the effects of the nonlinear behaviour of isolation pads on the seismic capacity of bridges to identify the parameters of base isolation systems that can be used to improve seismic performance of bridges. A parametric study was conducted by designing a set of bridges for three different soil types and varying the number of spans, span lengths, and pier heights. The seismic responses (acceleration, displacement and pier seismic forces) were evaluated for two structural models. The first model corresponded to the bridges supported on elastomeric bearings with linear elastic behaviour and the second model simulated a base isolated bridge that accounts for the nonlinear behaviour of the system. The seismic demand was represented with a group of twelve real accelerograms recorded on the subduction zone on the Pacific Coast of Mexico. The nonlinear responses under different damage scenarios for the bridges included in the presented study were estimated. These results allow determining the seismic capacity of the bridges with and without base isolation. Results show clearly the importance of considering the nonlinear behaviour on the seismic performance of bridges and the influence of base isolation on the seismic vulnerability of medium size bridges.


Biomolecules ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 27
Author(s):  
Iwona Sadura ◽  
Dariusz Latowski ◽  
Jana Oklestkova ◽  
Damian Gruszka ◽  
Marek Chyc ◽  
...  

Plants have developed various acclimation strategies in order to counteract the negative effects of abiotic stresses (including temperature stress), and biological membranes are important elements in these strategies. Brassinosteroids (BR) are plant steroid hormones that regulate plant growth and development and modulate their reaction against many environmental stresses including temperature stress, but their role in modifying the properties of the biological membrane is poorly known. In this paper, we characterise the molecular dynamics of chloroplast membranes that had been isolated from wild-type and a BR-deficient barley mutant that had been acclimated to low and high temperatures in order to enrich the knowledge about the role of BR as regulators of the dynamics of the photosynthetic membranes. The molecular dynamics of the membranes was investigated using electron paramagnetic resonance (EPR) spectroscopy in both a hydrophilic and hydrophobic area of the membranes. The content of BR was determined, and other important membrane components that affect their molecular dynamics such as chlorophylls, carotenoids and fatty acids in these membranes were also determined. The chloroplast membranes of the BR-mutant had a higher degree of rigidification than the membranes of the wild type. In the hydrophilic area, the most visible differences were observed in plants that had been grown at 20 °C, whereas in the hydrophobic core, they were visible at both 20 and 5 °C. There were no differences in the molecular dynamics of the studied membranes in the chloroplast membranes that had been isolated from plants that had been grown at 27 °C. The role of BR in regulating the molecular dynamics of the photosynthetic membranes will be discussed against the background of an analysis of the photosynthetic pigments and fatty acid composition in the chloroplasts.


2005 ◽  
Vol 8 (3) ◽  
pp. 247-257 ◽  
Author(s):  
Y. Fukumoto ◽  
T. Takaku ◽  
T. Aoki ◽  
K. A. S. Susantha

This paper presents the innovative use of hot-rolled thickness-tapered mill products, longitudinally profiled (LP) plates, for the seismic performance of bridge bents of single and portal framed piers. The study involves the inelastic cyclic testing and numerical analysis of tested beam-columns and portal frames in order to evaluate the effects of tapering ratios of LP plates, penetration of yielding, and number of locally buckled panels on their structural ductility. A structural design method is proposed for the portal frames having LP panels under cyclic loadings.


2010 ◽  
Vol 8 (1) ◽  
pp. 126-133 ◽  
Author(s):  
Purvee Bhardwaj ◽  
Sadhna Singh

AbstractIn this paper we focus on the elastic and thermodynamic properties of the B1 phase of CaO by using the modified TBP model, including the role of temperature. We have successfully obtained the phase transition pressure and volume change at different temperatures. In addition elastic constants and bulk modulus of B1 phase of CaO at different temperatures are discussed. Our results are comparable with the previous ones at high temperatures and pressures. The thermodynamical properties of the B1 phase of CaO are also predicted.


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