Papers by Author: Feng Zheng

Abstract: In order to provide a theoretical basis for the alignment regulation of prestressed box-girder bridge with corrugated webs, so that the control for alignment can be more targeted. Optimization model of alignment regulation for cantilever constructed pre-stressed box-girder bridge with corrugated webs is proposed based on optimization principle. The sensitivity of alignment error, transverse stress of bottom plate and transverse deformation of corrugated web with respect to design parameters is analyzed during three classical construction stages. The results indicate that the concrete density, concrete elastic modulus, longitudinal and transverse pre-stress are key control parameters of alignment regulation; alignment error is not sensitive to the change of uniformly distributed temporary loads; the cantilever state at one fourth span is most sensitive to the change of design parameters.

Abstract: Some secondary effect introduced by corrugated configuration of corrugated web was studied and formulas were proposed. The deduction for these formulas was resolved into two steps. Step I: to solve the behavior of whole corrugated web by considering it as an orthotropic plate; Step II: to solve the secondary effect according to the shape parameters of corrugation based on the result of Step I. Subsequently, a numerical experiment was designed to validate the analytical work with the help of finite element package ANSYS taking material nonlinearity into consideration. The results obtained from numerical and analytical methods show good agreement. It indicates that the formulas proposed in this paper are convenient and efficient. This research deals with this secondary effect for the first time; more studies are needed for the effect on local buckling of corrugated webs.

Abstract: In order to research the mechanic performance of 7A05 aluminum alloy, a series of tests, including tensile test about aluminum alloy substrate, tensile test about aluminum alloy butt welded joint, tensile test about transverse partition of aluminum alloy welded joint and hardness test were conducted. The results of these tests indicate that the strength and hardness of HAZ of this material exhibit a W-shaped reduction. There are an symmetrical softened area at 10~20mm from the center of weld. Due to ageing effect, the strength and hardness of HAZ can resume to 80%of the substrate one month after welding. Based on the analytical deduction and experimental data fitting, the theoretical strength model for HAZ of aluminum alloy is proposed. For the purpose of engineering design, the HAZ is transformed into a uniform strength reduction zone, the width and strength value is determined according to the principle of equal strength.

Abstract: The calculation model for torsion strength of prestressed concrete beams (PCs) under pure torsion is deduced theoretically based on Fixed-Angle Softened Truss Model (FA-STM) and an efficient algorithm for the model is proposed. The calculated values of torsion strength and the Torque-twist curves predicted by the proposed method agree well with these obtained from tests for the two specimens available in literature. These indicate that the proposed method can not only calculate the torsion strength efficiently but can also predict the load—deformation curve of the PCs.