Testing Research On Mechanical Properties Of Anchor Blocks In Externally Prestressed Concrete Structures

With the development of bridge construction industrialization, external prestressing technology is widely adopted all over the world. However, the externally prestressed concrete structures has its drawbacks, for the prestressed tendons are associated with prestressed congcrete bridges only by anchors and deviators, which may easily be destroyed by the extremely complex stress concentration, and lead to the prestressing loss. Hence, the reasonablity and safety of the anchors and deviators relates directly to the normal use of the externally prestressed concrete brides. The mechanical properties of anchor blocks are analyzed by means of theory studying, experimental test and numerical simulation in this paper. The main research contents are as follows:(1) Make a summary about the structure characteristics on anchors of different types. The corresponding application scope, advantages and disadvantages, and mechanical behavior are analyzed. Based on comparisons of design methods about anchor blocks in externally prestressed concrete structures proposed by the relevant specification and Scholars at home and abroad, design formulas and relevant scope of application of the anchor blocks in externally prestressed concrete structures are proposed.(2) Make an experimental research on anchor block according to past researches. The effects to the bearing capacity and failure patterns of the anchor block are studied, such as Shear span ratio, tensile reinforcement ratio. The tests contains six specimens, the development of cracks and the failure patterns, the Stress and strain distribution, the relative displacement, the effects to the bearing capacity, comparisons between the experimental value and the theoretical value are all analysed detailly.(3) According to the experimental research, considering the nonlinearity of material and geometry, some finite element nonlinear analysis are conduct by using ABAQUS to study the mechanical behavior and the failure patterns of the anchor blocks, and make a compression of the experimental and numerical simulation value, such as the load-relative displacement curves and load-strain curves, which are further compared with the conclusion obtained by the experiment to verify the effectiveness of the numerical simulation.