A Study On Utilized Quantity And Utilization Level Of Externally Bonded Strengthened Materials

Reinforced concrete structures are often in need of strengthening and repairing. For a new structure, such a need arises when the completed structure does not satisfy prescribed performance in term of strength and serviceability due to design errors and construction faults. In all these cases, cost effective solutions are required for structural strengthening.Among the many strengthening techniques available, the method of plate bonding has been an attractive one in recent years, due to its simplicity and speed of application and minimum increases in structural self-weight and size. Steel plate and fiber-reinforcement polymer (FRP) plate have both been used in plate bonding, depending on the requirement of a particular situation. Steel plates have been used very widely to strengthen RC beams, slab and also columns. Although a great deal of research has been carried out in recent years on the use of plate bonding for strengthening concrete structures, the work has generally been limited to concrete beams which almost supposed the bonding materials were used fully.However, the maximum utilized quantity of externally bonded strengthening materials of reinforced concrete structures depends on many factors including the type of materials, reinforcement ration of the sections, value of externally bonded strengthening materials and strength grade of concrete. Because of the contents above, the externally bonded strengthening materials quantity and the used value are specified in this paper.The main work carried out goes on as following:1. To study utilization level and bearing capacity of externally bondedsteel plates in axially loaded reinforced concrete columns.Utilization level and bearing capacity of externally bonded steel plates in axial loaded reinforced concrete columns depend on first loaded value, kinds of the externally bonded steel plate and strength degree of concrete. Based on the stress-strain relationship and limit strain value of concrete of Chinese "code for design of concrete structures"(GB50010 — 2002), the bound conditions of full utilization for the externally bonded steel plates were derived and the formulas of bearing...