• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.309-314
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• 2000

Stress concentration at haunches of Rahmen bridges was evaluated by means of FEM analysis. The selected haunches were of three different types; straight, skew and curved ones with$55^{\circ}$of angle respectively. The result showed that the effect of stress distribution was the lowest at the curved haunch and the highest at the straight one. Such a result could be used to provide some guidelines for revising related standard specifications.

• Steel and Composite Structures
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• v.23 no.5
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• pp.597-610
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• 2017

This paper presents a mathematical model for fixed-end moments of I-sections with straight haunches for the general case (symmetrical and/or non-symmetrical) subjected to a concentrated load localized anywhere on beam taking into account the bending deformations and shear, which is the novelty of this research. The properties of the cross section of the beam vary along its axis "x", i.e., the flange width "b", the flange thickness "t", the web thickness "e" are constant and the height "d" varies along of the beam, this variation is linear type. The compatibility equations and equilibrium are used to solve such problems, and the deformations anywhere of beam are found by the virtual work principle through exact integrations using the software "Derive" to obtain some results. The traditional model takes into account only bending deformations, and others authors present tables considering the bending deformations and shear, but are restricted. A comparison between the traditional model and the proposed model is made to observe differences, and an example of structural analysis of a continuous highway bridge under live load is resolved. Besides the effectiveness and accuracy of the developed models, a significant advantage is that fixed-end moments are calculated for any cross section of the beam "I" using the mathematical formulas.

• Smart Structures and Systems
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• v.22 no.6
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• pp.689-697
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• 2018

This paper presents a model of the elastic curve for rectangular beams with straight haunches under uniformly distributed load and moments in the ends considering the bending and shear deformations (Timoshenko Theory) to obtain the deflections and rotations on the beam, which is the main part of this research. The traditional model of the elastic curve for rectangular beams under uniformly distributed load considers only the bending deformations (Euler-Bernoulli Theory). Also, a comparison is made between the proposed and traditional model of simply supported beams with respect to the rotations in two supports and the maximum deflection of the beam. Also, another comparison is made for beams fixed at both ends with respect to the moments and reactions in the support A, and the maximum deflection of the beam. Results show that the proposed model is greater for simply supported beams in the maximum deflection and the traditional model is greater for beams fixed at both ends in the maximum deflection. Then, the proposed model is more appropriate and safe with respect the traditional model for structural analysis, because the shear forces and bending moments are present in any type of structure and the bending and shear deformations appear.

• Structural Engineering and Mechanics
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• v.31 no.3
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• pp.297-314
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• 2009

When the temperature of a structure varies, there is a tendency to produce changes in the shape of the structure. The resulting actions may be of considerable importance in the analysis of the structures having non-prismatic members. Therefore, this study aimed to investigate the modeling, analysis and behavior of the non-prismatic members subjected to temperature changes with the aid of finite element modeling. The fixed-end moments and fixed-end forces of such members due to temperature changes were computed through a comprehensive parametric study. It was demonstrated that the conventional methods using frame elements can lead to significant errors, and the deviations can reach to unacceptable levels for these types of structures. The design formulas and the dimensionless design coefficients were proposed based on a comprehensive parametric study using two-dimensional plane-stress finite element models. The fixed-end actions of the non-prismatic members having parabolic and straight haunches due to temperature changes can be determined using the proposed approach without necessitating a detailed finite element model solution. Additionally, the robust results of the finite element analyses allowed examining the sources and magnitudes of the errors in the conventional analysis.

• Journal of Korean Society of Steel Construction
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• v.29 no.1
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• pp.25-36
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• 2017

In the 1994 Northridge earthquake, connection damage initiated from the beam bottom flange was prevalent. The presence of a concrete slab and resulting composite action was speculated as one of the critical causes of the prevalent bottom flange fracture. In this study, four seismic retrofit schemes are proposed in order to salvage welded steel moment connections with composite floor slabs in existing steel moment frames. Because top flange modification of existing beams is not feasible due to the presence of a concrete floor slab, three schemes of bottom flange modification by using welded triangular or straight haunches or RBS(reduced beam section), and beam web strengthening by attaching heavy shear tab were cyclically tested and analyzed. Test results of this study show that haunch and web-strengthened specimens can eliminate the detrimental effect caused by composite action and ensure excellent connection plastic rotation exceeding 5% rad. Design recommendations for each retrofit scheme together with supplemental numerical studies are also presented.