A Mathematical Model to Simulate Static Characteristics of T-Beam Bridge with Wide Flange

This study considers various factors, such as shear lag effect and shear deformation, and introduces the self-stress equilibrium for shear lag warping stress conditions to analyze the static characteristics of T-beam bridges accurately. In the mechanical analysis, three generalized displacement functions are applied, and the governing differential equations and natural boundary conditions of the static characteristics of T-beams are established on the basis of the energy variational principle. In the example, the influences of the shear lag effect, different load forms, and span ratio on the mechanical properties of T-beam bridges are analyzed. Therefore, the method of this study enriches and develops the theoretical analysis of T-beams, and it plays a certain guiding role in designing such a structure.

Performance Evaluation of Concrete Pavement Slab Considering Creep Effect by Finite Element Analysis

Creep, as an intrinsic property of concrete material, will inevitably affect the performance of concrete pavement slabs in the field. However, the creep effect on the performances of concrete pavement slabs is far from being fully investigated. In this study, a test set-up is designed to measure the flexural creep of concrete beams exposed to both sealed and drying conditions. The measured flexural creep results are then modeled by the microprestress–solidification theory-based creep model which is incorporated into finite element analysis to evaluate numerically the creep effect on the moisture warping deformation, warping stress, and the total stress under traffic load in concrete slabs. Parameters including slab size, slab thickness, and subgrade modulus are considered. It is found that concrete creep has a significant effect on slab performance. Based on the measured creep properties in this study, the warping deformation of slabs can be reduced by 8–62%, and the warping stress and the total stress can be relaxed by at least 50%. Therefore, it is of importance to incorporate creep effect in analyzing warping deformation and stress generated in concrete pavement slabs. This study also provides a numerical methodology to the current performance evaluation of concrete slabs in the field.

Warping Torsional and Distortional Stress of Composited Box Girder with Corrugated Steel Webs

The torsional behaviors of composite box girders with corrugated steel webs are more obvious than traditional concrete girders due to the lower torsional rigidity. In this paper, the torsion and distortion of this kind of composite girder are studied. The formulas for warping normal stress and shear stress were put forward according to the second theory of Umanskii, considering the accordion effect of corrugated steel webs. Then, the influences of different dimensional parameters on the torsional and distortional stress are investigated. Results show that the effect of parameters on stress is different and implicit in composite box girders with corrugated steel webs. Under eccentric loads, the warping torsional and distortional stress in this kind of girder should not be neglected. Compared with girders under corresponding symmetric loads, the total warping stress may be as big as flexural normal stress, and the total shear stress usually reaches 30 to 50 percentage of flexural shear stress. So the warping stress and additional shear stress due to warping torsion and distortion are suggested to be calculated by the proposed equations in structural analysis, which are usually not taken into account in conventional concrete box girders.

An Efficient Direct Calculation Approach for Fatigue Assessment of Container Ships Concerning Bending and Warping Stresses

Container ships are particularly susceptible to torsional loads. The distribution of torsion-induced warping stress in a container ship hull is more complicated and difficult to be expressed by beam theory formulas. In practice, finite element (FE) analysis is typically used to calculate the stress response to wave-loading conditions. However, it is time consuming to compute hull girder stresses for all relevant sea conditions through FE analyses. In this paper, an efficient and robust approach is proposed by combining beam theory and FE analyses in the determination of hull girder stresses. The parameters required by beam theory can be regressed through matching stress records from a FE analysis with the corresponding sectional and pressure loads from the hydrodynamic simulation. Stress records obtained using the proposed method are utilized in fatigue assessment of a case study container vessel. The results show that the accuracy of the regression approach is satisfactory compared with the full FE analyses.

Ultimate Strength Analysis of a River-Sea Ship Under Combined Action of Torsion and Bending

For a River-Sea ship hull with a relatively low torsional rigidity due to the large deck openings, the analysis of the effect of torsion induced warping stress[1] on the structural strength as well as the ultimate hull strength interaction relationships between the torsion and vertical bending is of significant importance. The present study deals with the ultimate strength of a River-Sea ship under combined action of bending and torsion by the means of numerical and experimental research. Based on the results, a proposed equation defining the ultimate strength interaction relationship for this River-Sea ship is given.

Study on Web Parameters of Prestressed Concrete Composite Box Girder with Corrugated Steel Web

Taken the Chongqing PC composite box girder with corrugated steel web for background , spatial finite element calculation model is set up by adopting the mixed unit, the influence about geometric parameters of corrugated steel perforation is analyzed by used linear and nonlinear finite element calculation of steel box girder .It shows that bending stress and warping stress was reduced by increasing the bending angle of corrugated steel webs of composite beams, while the buckling strength improved obviously; the ratio of the top slab and the floor slab maximum thickness of box girder to the corrugated steel perforation should be about 20; the mechanical properties of composite beams will be improved by reducing the length of straight slabs of corrugated steel webs.

The Effect of Warping Stress on the Lateral-Torsion Buckling of Cold-Formed Zed-Purlins

An analytical model is developed for analysing the elastic lateral-torsion buckling of cold-formed zed-purlins with partially lateral restraint from metal sheeting. The model is used to estimate the effects of warping stresses on the lateral-torsion buckling behavior of cold-formed zed-purlins with various boundaries and interval braces provided by antisag bars. The results show that the warping stress only has remarkable influence on the lateral-torsion buckling when the boundary of the member is fixed and there is no antisag bar present.

Increase of Warping Rigidity in Open Sections of a Containership by Stiffening Plates

Distributions of warping stress and deformation of modules with open-section and longitudinal stiffening plates were determined by a finite-element program. Eleven models of various stiffnesses and configuration but under the same torsional moment were studied. The loading and overall hull size are close to a containership of 38 000-ton loading capacity. The prismatic thin-walled beam analysis was performed on a model to compare the results from the finite-element approach. It has been found that the warping rigidity can be effectively increased by installing plates along the axis of the ship. The maximum warping stresses, which are usually found at the hatch corners of the wing boxes, are evaluated and compared.