Researches on ultra-high performance concrete (UHPC) have been conducted worldwide owing to its outstanding durability and strength performances. The exploitation of the mechanical properties of UHPC will render it po...Researches on ultra-high performance concrete (UHPC) have been conducted worldwide owing to its outstanding durability and strength performances. The exploitation of the mechanical properties of UHPC will render it possible to achieve economic design through substantial reduction in the cross sectional dimensions and simplification in the reinforcement arrangement. This paper investigates experimentally the load transfer in the prestressed concrete anchorage zone. To provide distinctive features of UHPC compared to ordinary concrete, the cross sectional dimensions of the member were reduced and the stress distribution, deformation and cracking pattern of the PS anchorage zone were examined experimentally according to the degree of reinforcement of the members chosen. The distributions of the bursting stress, spalling stress and longitudinal edge stress in the specimens were observed according to the various types of reinforcement. All the specimens satisfied the load-bearing capacity criterion specified by the European ETAG-013 guidelines and their stress distributions were similar to those in the PS anchorages of post-tensioned members applying ordinary concrete. The cracks propagated longitudinally with lengths up to twice the cross sectional dimensions and their width was smaller than when applying ordinary concrete owing to the bridging effect of the steel fibers in UHPC. Accordingly, the exploitation of the high strength of UHPC enabled us to secure the resistance of the anchorage with no need for particular reinforcing devices.展开更多
A high resolution time measurement system with high data transfer rate was designed for the COLTRIMS (Cold Target Recoil-Ion Momentum Spectroscopy) system in Institute of Modern Physics,Chinese Academy of Sciences.It ...A high resolution time measurement system with high data transfer rate was designed for the COLTRIMS (Cold Target Recoil-Ion Momentum Spectroscopy) system in Institute of Modern Physics,Chinese Academy of Sciences.It is used to measure the Time of Flight(TOF) with a high resolution for all 20 channels.Based on the PCI Extensions for Instrumentation(PXI) standard,the readout electronics system consists of one Clock-Trigger fan-out module and four TOF modules.Test results show that the system meets the demands of COLTRIMS,with a time resolution of better than 25 ps and a data transfer rate over 20 MB/s.展开更多
文摘Researches on ultra-high performance concrete (UHPC) have been conducted worldwide owing to its outstanding durability and strength performances. The exploitation of the mechanical properties of UHPC will render it possible to achieve economic design through substantial reduction in the cross sectional dimensions and simplification in the reinforcement arrangement. This paper investigates experimentally the load transfer in the prestressed concrete anchorage zone. To provide distinctive features of UHPC compared to ordinary concrete, the cross sectional dimensions of the member were reduced and the stress distribution, deformation and cracking pattern of the PS anchorage zone were examined experimentally according to the degree of reinforcement of the members chosen. The distributions of the bursting stress, spalling stress and longitudinal edge stress in the specimens were observed according to the various types of reinforcement. All the specimens satisfied the load-bearing capacity criterion specified by the European ETAG-013 guidelines and their stress distributions were similar to those in the PS anchorages of post-tensioned members applying ordinary concrete. The cracks propagated longitudinally with lengths up to twice the cross sectional dimensions and their width was smaller than when applying ordinary concrete owing to the bridging effect of the steel fibers in UHPC. Accordingly, the exploitation of the high strength of UHPC enabled us to secure the resistance of the anchorage with no need for particular reinforcing devices.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences under Grant No.KJCX2-YW-N27
文摘A high resolution time measurement system with high data transfer rate was designed for the COLTRIMS (Cold Target Recoil-Ion Momentum Spectroscopy) system in Institute of Modern Physics,Chinese Academy of Sciences.It is used to measure the Time of Flight(TOF) with a high resolution for all 20 channels.Based on the PCI Extensions for Instrumentation(PXI) standard,the readout electronics system consists of one Clock-Trigger fan-out module and four TOF modules.Test results show that the system meets the demands of COLTRIMS,with a time resolution of better than 25 ps and a data transfer rate over 20 MB/s.
