The Study Of Unbonded And Efficient Anchorage Structure Of Prestressed CFRP Plate

The reinforcement technology of Prestressed CFRP plate is an active reinforcement technology of bridge,which has the double advantages of high specific strength and corrosion resistance of CFRP and high efficiency of closing cracks and increasing bearing capacity.Anchorage device is the core component of the prestressed carbon fiber reinforced system,convenient and reliable anchorage of carbon fiber board is the key to ensure the utilization rate of materials,reduce the difficulty of construction,and ensure the reinforcement effect and engineering safety.Among many anchorage devices,the wedge type anchorage is one of the most simple and efficient anchorage methods for CFRP.Among them,the wedge type anchorage is one of the most simple and efficient anchorage methods for CFRP plate.In this paper,based on the previous research and feedback of engineering application,the following research has been carried out:(1)Through the analysis of anchorage theory and finite element simulation,it is shown that the large hole end,small wedge end and the carbon fiber board in this position are the places where the stress is relatively concentrated.The measures of fillet or chamfering the contact edge of the anchor cup hole and wedge,increasing the angle difference,etc.can reduce the stress concentration of the anchorage.It is revealed that the top pressure has little effect on the anchorage performance when the CFRP and the wedge do not slip and the wedge follows freely in the anchor cup.Therefore,increasing the friction resistance of the contact surface between the wedge and the carbon fiber board,reducing the friction coefficient of the contact surface between the wedge and the anchor cup,making the wedge follow freely in the anchor cup,can realize the anchoring of the carbon fiber board under the condition of small pushing load.(2)Based on the analysis of the coordination between chemical bond and mechanical anchorage in the traditional wedge anchorage structure,and the influence of adhesive on the friction and anchorage technology of the contact surface between the CFRP and the wedge,the chemical bond was removed from the anchorage of the carbon fiber board,and the measures such as increasing the wedge input of the wedge were proposed to realize the non bond mechanical anchorage.Through the optimization of anchorage device,the anchorage technology is simplified,and a more simplified design concept of carbon fiber board tension system is provided.(3)The tensile test of CFRP is carried out to verify that for the optimized anchorage,under the condition of ensuring enough strength of the anchor cup and friction resistance of the wedge to the CFRP,the top pressure and friction coefficient of the anchor cup have an effect on the circumferential strain of the anchor cup during the tensile stage of the CFRP,but they are not the key influencing factors of the anchoring efficiency.The anchoring efficiency system of the anchorage after removing the adhesive has been verified The data can still meet the requirements of national and industrial specifications.Through the above work,on the basis of ensuring the anchoring efficiency of carbon fiber board,this paper cancels the use of adhesive in the anchorage of carbon fiber board with wedge type anchorage device,and realizes the low top pressure non bonding mechanical anchorage.Through the design of key parts of anchorage device,it simplifies the reinforcement system of prestressed carbon fiber board and the construction method of anchorage and tension,and further promotes the promotion of prestressed carbon fiber board technology application.