Load distribution in edge stiffened slab and slab-on-girder bridge decks

1988 ◽  
Vol 15 (6) ◽  
pp. 977-983 ◽  
Author(s):  
K. N. Smith ◽  
I. Mikelsteins
Keyword(s):  
Load Distribution ◽  
Limit State ◽  
Bending Moment ◽  
Beam Deflection ◽  
Highway Bridge ◽  
Bridge Design ◽  
Grillage Analysis ◽  
Single Vehicle ◽  
Beam Bending ◽  
Girder Bridge

The results of a study on the effect of edge beam geometry on the static live-load load distribution characteristics of single-span slab and slab-on-girder bridge superstructures are presented. Using a grillage analysis, the influence of various forms of edge stiffening on longitudinal bending moment and vertical deflection at midspan was investigated. Two load cases utilizing the Ontario Highway Bridge Design truck were considered. Of particular interest is the load case of a single vehicle in a travelled lane, as edge beam deflection under this condition is governed by a serviceability limit state design requirement of the Ontario Highway Bridge Design Code.For the bridge geometry and loadings considered, all types of edge stiffening significantly affect edge beam bending moment and deflection at midspan; the effect generally increases as the span decreases. Edge beam bending moment increases as the stiffness of the edge beam is increased. Considering the change in edge beam stiffness, edge beam deflection decreases even though the bending moment carried by the edge beam increases. The results of the grillage analysis agree well with an interpretation of the simplified method of analysis of the Ontario Highway Bridge Design Code. When the deflection criterion is affecting a bridge design, it would be beneficial to account for the edge stiffening. Key words: load distribution, edge stiffening, edge beams, bridge deck analysis, grillage analysis.

Ultimate load distribution characteristics of a model slab-on-girder bridge

1987 ◽  
Vol 14 (6) ◽  
pp. 739-752 ◽  
Author(s):  
M. S. Cheung ◽  
N. J. Gardner ◽  
S. F. Ng
Keyword(s):  
Load Distribution ◽  
Limit State ◽  
Ultimate Limit State ◽  
Live Load ◽  
Nonlinear Behaviour ◽  
Distribution Characteristics ◽  
Load Redistribution ◽  
Girder Bridge ◽  
Load Distribution Factors ◽  
Ultimate Limit

The introduction of limit states design philosophy and the ever growing demand for higher permissible loads for overload vehicles or special permit vehicles necessitates a thorough investigation of the behaviour and live load distribution characteristics of bridges beyond the working stress range. Evaluation of the live load moment capacity at ultimate utilizing elastic load distribution factors is neither realistic nor logical, as the distribution factors should reflect the ultimate structural/load responses including nonlinear behaviour, load redistribution due to yielding, etc.The purpose of this paper is to study load distribution characteristics of a slab-on-girder bridge model at ultimate loads and to develop load distribution factors for the ultimate limit state which include load redistribution, nonlinear behaviour, and other effects. Key words: load distribution factor, ultimate limit state, load redistribution, nonlinear behaviour, slab-on-girder bridge, OHBD truck.

scholarly journals Stability of crane beam walls with fatigue cracksin the compressed belt zone

2020 ◽  
Vol 17 (4) ◽  
pp. 47-53
Author(s):  
A. E. Kubasevich ◽  
Keyword(s):  
Crack Length ◽  
Bearing Capacity ◽  
Critical Stress ◽  
Fatigue Cracks ◽  
Limit State ◽  
Bending Moment ◽  
Limit States ◽  
Stress Strain ◽  
Beam Bending ◽  
Stress Parameters

The paper describes a method for assessing the bearing capacity of the crane beam walls with fatigue cracks. There has been developed and implemented an algorithm for evaluating the stress-strain and limit state of the beam with a crack in the wall under a compressed belt. There has been established the dependence of the stress-strain and limit states of the beam wall on the value of the initial relative beam bending and the crack length in the section under the action of the bending moment and transverse force. The author presents the results of numerical studies of the effect of cracks on the bearing capacity of the beam wall. The influence of the amplitude of the initial beam wall deflection on the critical stress parameters is revealed. The dependence of the values of critical stress parameters on the relative crack length is considered.

Comparison of Canadian Highway Bridge Design Code and AASHTO LRFD Bridge Design Specifications regarding pile design subject to negative skin friction

2020 ◽  
Vol 57 (7) ◽  
pp. 1092-1098
Author(s):  
James R. Bartz ◽  
James A. Blatz
Keyword(s):  
Skin Friction ◽  
Drag Force ◽  
Limit State ◽  
Highway Bridge ◽  
Ultimate Limit State ◽  
Design Code ◽  
Bridge Design ◽  
Negative Skin Friction ◽  
Design Specifications ◽  
Aashto Lrfd

Negative skin friction acting on piles has long been included in the design of bridge foundations subject to ground settlement. However, currently there are inconsistencies in how negative skin friction and drag force are incorporated into the calculation of the geotechnical ultimate limit state (ULS), partly due to differences in the design codes. The latest editions of the Canadian Highway Bridge Design Code and AASHTO LRFD Bridge Design Specifications are compared with the analysis of a hypothetical steel H-pile, driven through a settling clay layer into a dense, nonsettling layer. The results show that foundation designs can be significantly more conservative and costly when adhering to the AASHTO code because this code includes the drag force in the geotechnical ULS. It is concluded that adhering to the CHBDC can result in a reduced foundation system by considering the actual force distribution in the pile.

Combined flexure and torsion of I-shaped steel beams

1989 ◽  
Vol 16 (2) ◽  
pp. 124-139 ◽  
Author(s):  
Robert G. Driver ◽  
D. J. Laurie Kennedy
Keyword(s):  
Limit State ◽  
Bending Moment ◽  
Phase Behaviour ◽  
Inelastic Interaction ◽  
Steel Beams ◽  
Ultimate Limit State ◽  
Second Phase ◽  
Design Standards ◽  
Limit States ◽  
Interaction Diagram

Design standards provide little information for the design of I-shaped steel beams not loaded through the shear centre and therefore subjected to combined flexure and torsion. In particular, methods for determining the ultimate capacity, as is required in limit states design standards, are not presented. The literature on elastic analysis is extensive, but only limited experimental and analytical work has been conducted in the inelastic region. No comprehensive design procedures, applicable to limit states design standards, have been developed.From four tests conducted on cantilever beams, with varying moment–torque ratios, it is established that the torsional behaviour has two distinct phases, with the second dominated by second-order geometric effects. This second phase is nonutilizable because the added torsional restraint developed is path dependent and, if deflections had been restricted, would not have been significant. Based on the first-phase behaviour, a normal and shearing stress distribution on the cross section is proposed. From this, a moment–torque ultimate strength interaction diagram is developed, applicable to a number of different end and loading conditions. This ultimate limit state interaction diagram and serviceability limit states, based on first yield and on distortion limitations, provide a comprehensive design approach for these members. Key words: beams, bending moment, flexure, inelastic, interaction diagram, I-shaped, limit states, serviceability, steel, torsion, torque, ultimate.

Anchor rod forces and maximum bending moments in sheet pile walls using the factored strength approach

1996 ◽  
Vol 33 (5) ◽  
pp. 815-821 ◽  
Author(s):  
A B Schriver ◽  
A J Valsangkar
Keyword(s):  
Water Pressure ◽  
Limit State ◽  
Bending Moment ◽  
Ultimate Limit State ◽  
Sheet Pile ◽  
Limit States ◽  
Working Stress ◽  
Geotechnical Design ◽  
Ultimate Limit State Design ◽  
Sheet Pile Wall

Recently, the limit states approach using factored strength has been recommended in geotechnical design. Some recent research has indicated that the application of limit states design using recommended load and strength factors leads to conservative designs compared with the conventional methods. In this study the influence of sheet pile wall geometry, type of water pressure distribution, and different methods of analysis on the maximum bending moment and achor rod force are presented. Recommendations are made to make the factored strength design compatible with conventional design. Key words: factored strength, working stress design, ultimate limit state design, anchored sheet pile wall, bending moment, anchor rod force.

Elastic-plastic bending of the pipeline under combined loading

2021 ◽  
pp. 372-377
Author(s):  
Виктор Миронович Варшицкий ◽  
Евгений Павлович Студёнов ◽  
Олег Александрович Козырев ◽  
Эльдар Намикович Фигаров
Keyword(s):  
Internal Pressure ◽  
Limit State ◽  
Bending Moment ◽  
Axial Direction ◽  
Longitudinal Force ◽  
Combined Loading ◽  
Dimensional Problem ◽  
Elastic Plastic ◽  
Pipeline Section ◽  
Thin Walled Pipe

Рассмотрена задача упругопластического деформирования тонкостенной трубы при комбинированном нагружении изгибающим моментом, осевой силой и внутренним давлением. Решение задачи осуществлено по разработанной методике с помощью математического пакета Matcad численным методом, основанным на деформационной теории пластичности и безмоментной теории оболочек. Для упрощения решения предложено сведение двумерной задачи к одномерной задаче о деформировании балки, материал которой имеет различные диаграммы деформирования при сжатии и растяжении в осевом направлении. Проведено сравнение с результатами численного решения двумерной задачи методом конечных элементов в упругопластической постановке. Результаты расчета по инженерной методике совпадают с точным решением с точностью, необходимой для практического применения. Полученные результаты упругопластического решения для изгибающего момента в сечении трубопровода при комбинированном нагружении позволяют уточнить известное критериальное соотношение прочности сечения трубопровода с кольцевым дефектом в сторону снижения перебраковки. Применение разработанной методики позволяет ранжировать участки трубопровода с непроектным изгибом по степени близости к предельному состоянию при комбинированном нагружении изгибающим моментом, продольным усилием и внутренним давлением. The problem of elastic plastic deformation of a thin-walled pipe under co-binned loading by bending moment, axial force and internal pressure is considered. The problem is solved by the developed method using the Matcad mathematical package by a numerical method based on the deformation theory of plasticity and the momentless theory of shells. To simplify the solution of the problem, it is proposed to reduce a twodimensional problem to a one-dimensional problem about beam deformation, the material of which has different deformation diagrams under compression and tension in the axial direction. Comparison with the results of numerical solution of the two-dimensional problem with the finite element method in the elastic plastic formulation is carried out. The obtained results of the elastic-plastic solution for the bending moment in the pipeline section under combined loading make it possible to clarify criterion ratio of the strength of the pipeline section with an annular defect in the direction of reducing the rejection. Application of the developed approach allows to rank pipeline sections with non-design bending in the steppe close to the limit state under combined loading of the pipeline with bending moment, longitudinal force and internal pressure.

Three Dimensional Grillage Analysis of Reactions on Supports of a Pre-Erection Block

2013 ◽  
Author(s):  
Sungchan Kim ◽  
Cheolho Ryu ◽  
Youngho Kim ◽  
Changbong Han ◽  
Dong Geun Kim
Keyword(s):  
Load Distribution ◽  
Three Dimensional ◽  
Evaluation Process ◽  
Center Of Gravity ◽  
Integrated System ◽  
Structural Safety ◽  
Detail Design ◽  
Grillage Analysis ◽  
Cad Models ◽  
Reaction Forces

There are many PE(Pre-Erection) Blocks in open areas of the shipyard, which are supported by the wooden, concrete, or steel supports. Their position and numbers are decided on a basis of the workers’ experiences. Recently, many shipyards have been making PE blocks with various shape and weight distribution because of the variety of kinds of ships and their building technology. Seriously, they are treating blocks which have not been experienced. In order to evaluate the reliability of all support plans of PE Blocks in such situation, many man hours (MH) are consumed, and the special knowledge and technology about structural analysis are required. We proposed how to conveniently and quickly evaluate the structural safety on PE block supports and developed an application system to implement the evaluation process with three dimensional part models of the PE block and their weight information. The evaluation is based on the simplification to a grillage model of a PE block and its grillage analysis. The load distribution on the grillage model is calculated by two approaches. The first is that the load distribution on the grillage nodes are estimated with the real weight and the center of gravity of each part of a PE block, which can be provided from design databases of the shipyard. The other is that the load distribution is optimally estimated only with the weight and the center of gravity of sub blocks of a PE block. The latter is useful in the case that block information of mother ships can be obtained without the detail design of the PE block. The integrated system has been comprehensively implemented in order to make the grillage model from the three dimensional CAD models of the PE block and their weight information, and to perform the grillage analysis for the reaction forces on the block supports. In the application program, the grillage model can be automatically built from CAD models of PE block. Also the grillage can be modified by inserting, splitting, and deleting a beam element.

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