| Fiber reinforced polymer/plastic(FRP)has attracted more and more attention and applications in the field of civil engineering due to its outstanding properties such as high specific strength,specific stiffness,corrosion resistance and fatigue resistance.With the rapid development of economy,the construction of large-span bridges has been put on the agenda.However,the application of traditional steel cable in largespan bridges is limited due to its shortcomings such as self-weight,easy corrosion and easy fatigue.The FRP material has become a popular candidate to replace steel as a new type of cable due to its excellent performance.Basalt fiber reinforced polymer/plastic(BFRP)is expected to be more widely studied and applied in the field of bridge due to its low production cost and high performance.When applied as bridge cable,BFRP may be subjected to lateral impact loads such as vehicle impact during service.FRP material is a significant anisotropic material,and its matrix material is a temperature-sensitive material.This paper used the Instron Ceast 9340 impact testing machine and universal testing machine MTS to test the lateral impact resistance and residual tensile loading capacity of the BFRP tendon under different conditions,and the damage morphology of the BFRP tendon at the impact face is observed with electron microscope.The main investigations and results of this paper are as follows:(1)The low velocity impact response of BFRP bars under the coupling action of4 groups of pre-tension ratio(2%,10%,20% and 30%)and 4 groups of impact energy(12.76 J,19.14 J,25.52 J and 31.90J)at room temperature was tested.Meanwhile,the residual tensile loading capacity of the incompletely broken specimens was further measured.Experimental results indicate that the failure modes of BFRP tendon include resin failure on the impact side,partial fracture of the fiber and complete fracture of the BFRP tendon.Under 19.14 J impact energy,the failure mode of the BFRP tendon changes from resin failure on the impact side to partial fracture of the fiber when the pretension ratio is increased from 2% to 10% and 20%.Meanwhile,the applied pretension enhances energy consumption,but the influence on the peak force is minimal.When the BFRP tendon is not completely broken,the residual deformation,energy consumption and the impact contact time of the specimen are negatively related to the pretension ratio.When the BFRP tendon is completely broken,the residual deformation of BFRP tendon decreases with the pretension ratio while the energy consumption and impact time first increases and then decreases with the pretension ratio.And the residual tensile loading capacity of the BFRP tendon decreases with the increase of impact energy.The impact damage level of BFRP tendon can be appropriately assessed with both the residual tensile loading capacity and the ratio between energy consumption and total impact energy(energy absorption ratio)of the specimen.(2)The lateral impact resistance and residual tensile loading capacity of BFRP tendon under the coupling action of different temperatures(-20℃,25℃,50℃ and90℃)and impact energy(12.76 J,19.14 J,25.52 J and 31.90 J)were studied.The results show that the failure mode and peak force of BFRP tendon are not significantly affected by the change of test temperature,but the residual deformation and energy consumption of the specimens show an upward trend when the temperature increased.When the impact energy increased,the peak force,residual deformation and energy consumption of the specimen all increase,but the impact time first increases and then decreases.Under the impact energy of 12.76 J,the residual tensile bearing capacity of BFRP tendon decreases with the increase of temperature.At room temperature,the residual tensile bearing capacity of BFRP tendon is the highest when the impact energy is 12.76 J.The energy absorption ratio of BFRP tendon under different impact energy shows different trends with the change of temperature.(3)The transverse impact resistance and residual tensile capacity of BFRP tendon were tested under the low impact energy(12.76 J)with the change of pre-tension and temperature.The results show that the failure mode of BFRP tendon is not significant affected by the coupling effect of temperature and pretension.Compared with the influence of temperature on the peak load,the influence of pretension is more significant.Both of the maximum deformation and residual deformation at the impact point of BFRP tendon increases when the test temperature increase.While the application of pretension shows the opposite result.The application of pretension reduces the energy consumption of BFRP tendon,and the energy consumption is the lowest at room temperature.The influence of pretension and temperature on the residual tensile loading capacity of BFRP tendon is mutual.After different pretension and temperature,BFRP tendon may have the same residual tensile loading capacity. |
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