Abstract:The full-scale model tests of two large cable-stayed Bridges (Nancha Bridge of Nanjing Yangtze River No. 2 Bridge and North Cha Bridge of Runyang Yangtze River Highway Bridge) are briefly introduced, and the anti-cracking safety factor and ultimate bearing capacity of cable pylon anchoring area are studied. At the same time, the rational arrangement of the prestressed cables in the anchoring area of the cable tower and the simulation effect of the cable tower segment model on the whole cable tower are also studied, which has theoretical guiding significance and practical value for the cable tower design of cable-stayed bridge.

Abstract:Through the establishment of linear and nonlinear finite element analysis models conforming to the characteristics of the containment structure of advanced nuclear power plants, a reasonable prestressed tension sequence of the containment is obtained, and the working performance and ultimate bearing capacity of the containment under design accident internal pressure and severe accident internal pressure are calculated. The results are compared with the large-scale structural model test results of 1:10, and a consistent conclusion is reached: advanced Nuclear power plant containment meets the international qualification standard of ultimate bearing capacity ≥2.5 times design internal pressure. The rationality of the conceptual design of containment for advanced nuclear power plant is verified.

Abstract:Based on the test of four flat beam-column joints, a set of design methods for the inner and outer core areas of flat beam-column joints considering the steel fiber in the inner and outer core areas and the unbonded prestressed tendons in the flat beam are obtained through theoretical derivation. The method makes full use of the strength of concrete in the inner and outer core areas of the joint, correctly considers the role of column axial pressure, and carefully checks the vertical shear resistance of the joint. The reliability of the proposed design method is verified by the experimental data.

Abstract:In the construction of water conservancy and hydropower projects, prestressed anchor cables (rods) are usually used to strengthen unstable slopes to improve their stability. However, up to now, the design of prestressed anchorage is mostly too conservative, resulting in too much engineering waste, and the anchorage design theory and method need to be further studied. By analyzing the factors affecting the design parameters of rock anchor and applying optimization and decision theory, the method of determining the design parameters of rock anchor is proposed, and the decision support system RSASYS for rock anchor support design is established, which provides a new analysis method for engineering designers to design rock anchor. The practice proves that this method is feasible and can obtain great economic benefit.

Abstract:Through the test of 6 unbonded prestressed two-way plates, the main factors affecting the deformation of two-way plates are studied, such as the structural form and the ratio of prestressed reinforcement. The influence of the side beam on the maximum deflection in the span of simply supported plate is converted into load and support condition coefficients. The effect of prestressed and non-prestressed tendons in two directions on the maximum deflection in the span of simply supported plates is reflected by the reduced ratio of reinforcement (ApQ) parameter, and the formula for calculating the short-term stiffness and deformation of unbonded prestressed simply supported plates is established. The calculated results agree well with the experimental results.

Abstract:Based on the cross section equilibrium equation and structural equilibrium equation, a numerical algorithm of aging analysis is proposed to calculate the aging effect of prestressed concrete structures by considering the shrinkage and creep of concrete and the relaxation of prestressed steel beam. This method can be used to predict the stress and deflection of prestressed concrete structures at any time from construction to operation to the whole design period. This theory has been verified by experiments and has been applied in practical bridge engineering.

Abstract:An experimental study on the long-term performance of prestressed composite beams has been carried out for the first time in China. The long-term deformation of prestressed composite beams, the strain of prestressed tendons, the strain of steel beams, and the slip between steel beams and concrete slabs are systematically studied through a one-year long-term load test. Based on the method of effective modulus of age adjustment, the creep stiffness matrix and creep force vector of prestressed composite beam elements are derived, and a time-dependent analysis program is developed.

Abstract:This paper discusses the development, construction characteristics and prefabrication methods of segment-by-span prefabricated Bridges. Combined with the new Liuhe Bridge project in Shanghai, the design features of precast segment beams are introduced, the construction method of constructing by hole with bridge erecting machine, the application of new prestressed materials and new technology, and the main test results of precast segment beams are analyzed.