Papers by Keyword: Shear Lag

Abstract: We establish the entity model of groove beams in Midas FEA. Then we compare and analysis the shear lag effect of prestressed reinforcement caused in different locations. It can provide some suggestions for prestressed rib of groove beams. The result shows that when the prestressed steel beam is located in the middle of small beam, the effect of shear lag is maximum and the shear lag effects of prestressed in two ends are similar, Prestressed reinforcement can be arrangement refer to the results.

Abstract: The main bridge of Yunshi Hanjiang River Bridge is a prestressed concrete extradosed bridge with two pylons, a single cable plane and with span arrangement (128+238+128) m. The main girder of the bridge is the concrete continuous triple-cell single box girder of long cantilevers and variable sections, the box girder is 26.5m wide. The cantilever of girder is 5.75m wide as to reduce the self-weight of main girder. In the design, the software Dr.Bridge was used to establish the finite element model for the box girder and to carry out the global calculation of the girder lateral calculation. The software ANSYS was used as well to establish the finite element model for the segments of the main girder and to carry out the analysis of the local stress of the girder. The results of the calculation and analysis indicate that the global structure of the bridge is safe and reliable and the structure can meet the requirements for highway vehicle riding safety and comfort. No significant local stress concentration appears in the main girder, the stress amplitude values of the stay cables are within 30Mpa, and the structure can meet the requirements for durability in the process of service of the bridge. With long cantilever design greatly reduce the self-weight of main girder and saving cost, at the same time make the bridge look lighter and beautiful. The results of the analysis provide a reference for analysis on the shear lag effect and lateral calculation of the concrete continuous triple-cell single box girder of long cantilevers and variable sections.

Abstract: This paper introduces the test and analysis of shear lag effect of a vast scale model of a continuous box girder with variable depth under symmetric lateral varying concentric loads. The strain distribution of the top plates and bottom ones of three cross-sections is tested, while the concentric loads respectively forced on the middle section and the quartile ones. Those sections are: the root-section of the cantilever, mid-section and one quartile section. Test shear lag coefficients of feature points were got through dividing the test strains to those calculated by elementary beam theory. They are compared with those soluted by method of energy variational calculus. The comparing result shows that the shear lag coefficients of the top plate shift from positive to negative accompanying with the load position from ribs to mid point of top plate. At the same time, the overall shear lag coefficient level increases. Meanwhile that of the corresponding bottom plate distribution character finely changes, but its overall shear lag coefficient declines that means that the contribution to bending resisting of bottom weakens. Lateral position of concentric loads has fine influence on shear lag of those sections relatively far from the loads.

Abstract: In this paper,a brief and effective finite element analysis model is established though using the ETABS.The influence of strengthened story’s quantity and location to the Sheer Lag Effect through the elastic linear analysis was researched.The variation of the Sheer Lag Effect in the process of the changing quantity and location of strengthened story and so on are discussed.The influence relation of strengthened story by the Sheer Lag Effect is analyzed,which has the important practical significance to reality structure design.

Abstract: By mean of the energy functional variational principle and considering shear lag effect of flange, the dynamic governing differential equation for the I-section cantilever beam in the action of compressive load P at the member end is obtained. The equation is solved by the separation variable method. According to the weigh residual method, the relation between natural frequency coefficient and critical load coefficient as well as the flutter critical load coefficient are made, the influence of shear lag effect on natural frequency coefficient and critical load coefficient is discussed.

Abstract: During the last two decades, active research has gone into the theoretical and the practical aspects of the electro-mechanical impedance (EMI) technique for structural health monitoring (SHM).This paper reviews the theoretical developments in modelling the force transfer mechanism between the piezoelectric-ceramic (PZT) patch and the host structure pertinent to the EMI technique. The review covers the modelling efforts spanning about last one and a half decades. The models reviewed include the shear lag based model, simplified shear lag model, the refined shear lag model and the continuum shear lag model. The first three listed models ignored the inertia term. The last model, that is the continuum based model, takes care of all the piezo, structural and adhesive effects rigorously and simultaneously. Typical comparisons between the outcomes resulting from the models are discussed.

Abstract: The shear lag and shear deformation effects on deflection of composite girder with corrugated steel webs (CGCSW) was studied. The influence of shear lag and shear deformation effect was expressed by deflection coefficient δ1 and δ2. Parametric analysis within a scope of dimensions of built-in girders was performed, including girder span, width, height, thickness of concrete flange and thickness of steel web. The results show that the deflection coefficient of shear lag effect is approximately directly proportional to square of width-span ratio, while the deflection coefficient of shear deformation effect is related to all parameters. It’s suggested that shear lag effect on CGCSW’s deflection be neglected when width-span ratio is smaller than 1/9, and shear deformation effect should always be considered.

Abstract: The tensile and compression performance and shear performance should not be changed when using variation principle to analyze shear lag of box beams. So based on transformed-section method, the section composed with steel and concrete can be transformed to one section made of supposing material. The shear lag of supposing section is analyzed to calculate the distribution of normal stress, then according to the constitutive relation of steel and concrete, the stress of actual section can be obtained. At last, the formula of normal stress in flange slab for reinforced concrete box girder is given.

Abstract: This paper presents an method to solve the vertical deflection of the box beams with corrugated steel webs, considering both the shear lag and shear deformation of corrugated steel webs. The method is deduced by means of the variational principle. The formulas given by this method is simple and practical. Then, a comprehensive analysis on the effects of shear lag and shear deformation of corrugated steel webs is given for a simply supported box beam with corrugated steel webs under uniformly distributed. The results of vertical deflection obtained by this paper are in good agreement with those obtained by the finite element method (FEM) and the model test, respectively.

Abstract: Based on six basic assumptions and deformation behaviour, the total potential energy of arches are obtained. The basic displacement functions are expressed with spline function. According to minmum potential energy principle, the characteristic equation is deducted. The characteristic value is solved by multiplication power method. An exampleof arches in the action of endmoment is calculated. The critical positive and negtive moment of out-of-plane stability in arches with single sysmetry axis section are studied.