scholarly journals ANALYSIS STUDY ON CHANGE OF TENDON TENSION FORCE DISTRIBUTION DURING THE PRESSURIZATION PROCESS OF PRESTRESSED CONCRETE CONTAINMENT VESSEL (PCCV)

Author(s):  
Takako KASHIWASE ◽  
Hideo NAGASAKA
Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2087 ◽  
Author(s):  
Danhui Dan ◽  
Pengfei Jia ◽  
Guoqiang Li ◽  
Po Niu

It is typically difficult for engineers to detect the tension force of prestressed tendons in concrete structures. In this study, a smart bar is fabricated by embedding a Fiber Bragg Grating (FBG) in conjunction with its communication fiber into a composite bar surrounded by carbon fibers. Subsequently, a smart composite cable is twisted by using six outer steel wires and the smart bar. Given the embedded FBG, the proposed composite cable simultaneously provides two functions, namely withstanding tension force and self-sensing the stress state. It can be potentially used as an alternative to a prestressing reinforcement tendon for prestressed concrete (PC), and thereby provide a solution to detecting the stress state of the prestressing reinforcement tendons during construction and operation. In the study, both the mechanical properties and sensing performance of the proposed composite cable are investigated by experimental studies under different force standing conditions. These conditions are similar to those of ordinary prestressed tendons of a real PC components in service or in a construction stage. The results indicate that the proposed smart composite cable under the action of ultra-high pretension stress exhibits reliable mechanical performance and sensing performance, and can be used as a prestressed tendon in prestressed concrete structures.


2018 ◽  
Vol 8 (11) ◽  
pp. 2139 ◽  
Author(s):  
Long Chen ◽  
Jinjie Chen ◽  
Jianxi Wang

There is confusion in the original design concept for the tensioning of longitudinally connected reinforcement of the CRTSII (China Railway Track System) slab ballastless track. In order to clarify the effect of tension value of longitudinal reinforcement on the mechanical characteristics of the ballastless track, a three-dimensional finite element model, considering the nonlinear interaction between the track slab and cement-emulsified asphalt (CA) mortar of the CRTSII slab ballastless track, was established. The mechanical characteristics of the track structure under longitudinal tension load and temperature gradient load of the longitudinal joint were calculated. A method of applying prestress to post-pouring concrete was proposed according to the concept of prestress loss of pretensioning prestressed concrete, a reasonable tensile force value was proposed after the crack width, and the reinforcement stress of the ballastless track in the operation stage was checked and calculated according to the concrete design principle. When the tension force is greater than 300 kN, it is harmful to the bonding between the slab and mortar layer, which is prone to interlayer damage. In order to add prestress to concrete with wide joints to ensure the longitudinal stability of the ballastless track, and that the reinforcement stress and crack width meet design requirements, it is suggested that the tension force value should be 230 kN. Further, the temperature difference between reinforcement and concrete should be 30 °C before the initial curdle of wide joint concrete.


Author(s):  
Dein Shaw ◽  
H. C. Lin

In this study, the tension force distributions in the film of COF cartridge are studied. It is noted that if the tension force on the film is too high, the interface between chip and film cracked. If the force is too low, there is no enough friction force to keep the COF in fix position when the cartridge is on the transportation vehicle. The relative motion between the chips of lower layer and the film of upper layer will cause the fatigue of interface of chips and film. It is also important to note that due to the friction the tension force at any section of the film is different. To fine the force distribution, a method to determine the tension force is developed and only effect of axial direction is considered. The assumption makes the film behave like a string. The results show that the forces on the film are different whenever the film passes a chip underneath.


2010 ◽  
Vol 5 (4) ◽  
pp. 452-462 ◽  
Author(s):  
Anton Andonov ◽  
◽  
Dimitar Stefanov ◽  
Marin Kostov

A direct procedure is proposed for capacity assessment of prestressed concrete containment structures subjected to internal accident loads. The assessment procedure is based on graphical comparison between the structural capacity and the load intensity by plotting both parameters in the same “temperature gradient – overpressure” coordinate system. Furthermore, the capacity in terms of structural integrity and leak tightness is evaluated, corresponding to different limit states or performance levels. A new damage index is proposed in order to correlate the intensity of damages on the containment structure with the load intensity. The criteria for leak tightness and structural integrity are adopted for VVER-1000 containment structure. The ultimate pressure capacity, the failure mode and the capacity corresponding to different performance levels of the containment structure are assessed. The influence of the temperature load on the structure response is also studied. Conclusions are drawn on the VVER-1000 containment vessel overpressure capacity and its response to different design basis and severe accidents. The main failure mode and the critical zones of the structure are also determined.


Sensors ◽  
2015 ◽  
Vol 15 (6) ◽  
pp. 14079-14092 ◽  
Author(s):  
Keunhee Cho ◽  
Sung Park ◽  
Jeong-Rae Cho ◽  
Sung Kim ◽  
Young-Hwan Park

Sensors ◽  
2016 ◽  
Vol 16 (8) ◽  
pp. 1317 ◽  
Author(s):  
Keunhee Cho ◽  
Jeong-Rae Cho ◽  
Sung Kim ◽  
Sung Park ◽  
Young-Jin Kim ◽  
...  

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