Study On Aging Damage Repairment Of Old Transmission Tower Concrete Foundation Main Column

The part of tower concrete foundation main columns of the old high-voltage transmission line(such as running for more than 25 years)were resulting in aging damage due to eroded by the natural environmental factors long time,which making their bearing performance and durability significantly reduce.In this paper,two kinds of repair methods that are repair reagent and increasing section were proposed for the different damage level of the tower foundation main columns,meanwhile the repair effect of two repair methods was conduct to experimental research.The concrete foundation main columns of 500 kV typical transmission line tower were detected,and causes and mechanism of damage of the tower foundation main columns was analyzed.The compressive strength and the anti-carbonation performance of the concrete with repair reagent at different age were tested,and the age and concrete strength on the repairing effect of the compressive strength and the increasing effect of the anti-carbonation performance were analyzed.The results show that the repairing effect of the compressive strength show the law of increase at first and then decrease with the increasing of the age,which is best at age 28d;The increasing effect of the anti-carbonation performance show the law of gradually decrese with the increasing of the age.The bearing performance of low-strength concrete short columns with repair reagent was experimental studied,and the repair reagent dosage and concrete strength on the repairing effect of the bearing performance was analyzed.The results show that the repairing effect of the bearing performance is increase with the increase of the repair reagent dosage.The bearing performance of the short column specimens after reinforced was experimental studied,and the effect of loading method,reinforcement thickness,strength of reinforcement material,eccentric eccentricity on the bearing capacity of the specimens was analyzed.The results show that increasing the thickness of the reinforcement can greatly improve the axial compression bearing capacity of the specimens after reinforced;Increasing the strength of the reinforcement material can improve the bearing capacity of the specimen after reinforced,while the increasing degree of the axial compression bearing capacity is not obvious when the gap is too large between the strength of the reinforcement materia and the original;The biaxial eccentric compression bearing capacity of the specimens decreases with the increase of eccentricity.Finally,the calculation formula of the biaxial eccentric ultimate bearing capacity of the specimens after reinforced is derived,and the correctness of the derived formula was analyzed combined with the experimental results,which can provide reference for reinforcement scheme design and engineering application.