The Lateral Buckling of Steel-Concrete Composite П-Beam

2008 ◽  
Vol 400-402 ◽  
pp. 287-293
Author(s):  
Li Zhong Jiang ◽  
Lin Lin Sun ◽  
Xing Li
Keyword(s):  
Bending Moment ◽  
Computing Methods ◽  
Lateral Buckling ◽  
Computing Model ◽  
Negative Moment ◽  
Numerical Computing ◽  
Negative Bending ◽  
The Stability ◽  
Simplified Calculation ◽  
Elastic Stage

Based on the theoretical analysis of steel-concrete composite П-beam’s lateral buckling, the computing model and simplified computing model on the stability of composite П-beams are brought forward. According to above two models, composite beam’s lateral buckling is studied in negative moment regions using the energy method, and the formulas which are used to calculate critical bending moment in negative moment regions in the elastic stage are deduced. Compared with other stability theories and methods, this paper represents the design correction and suggestion about the stability of composite П-beam in negative bending regions. Moreover, the simplified calculation method, which is used to compute the lateral critical buckling moment of steel-concrete composite П-beam loaded by equal-end moment, not only simplifies the computing process, the computing results also have the equivalent accuracy with numerical computing methods.

scholarly journals On Flexural Performance of Girder-To-Girder Wet Joint for Lightweight Steel-UHPC Composite Bridge

2020 ◽  
Vol 10 (4) ◽  
pp. 1335 ◽  
Author(s):  
Shuwen Deng ◽  
Xudong Shao ◽  
Banfu Yan ◽  
Yan Wang ◽  
Huihui Li
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Bending Moment ◽  
Inhibitory Effect ◽  
Careful Consideration ◽  
Joint Interface ◽  
Test Results ◽  
Negative Moment ◽  
Composite Bridge ◽  
Negative Bending

Joints are always the focus of the precast structure for accelerated bridge construction. In this paper, a girder-to-girder joint suitable for steel-ultra-high-performance concrete (UHPC) lightweight composite bridge (LWCB) is proposed. Two flexural tests were conducted to verify the effectiveness of the proposed T-shaped girder-to-girder joint. The test results indicated that: (1) The T-shaped joint has a better cracking resistance than the traditional I-shaped joint; (2) The weak interfaces of the T-shaped joint are set in the areas with relatively lower negative bending moment, and thus the cracking risk could be decreased drastically; (3) The natural curing scheme for the joint is feasible, and the reinforcement has a very large inhibitory effect on the UHPC material shrinkage; The joint interface is the weak region of the LWCB, which requires careful consideration in future designs. Based on the experimental test results, the design and calculation methods for the deflection, crack width, and ultimate flexural capacity in the negative moment region of LWCB were presented.

Research on Key Issues in Design of Outer-Plated Steel-Concrete Continuous Composite Beams

2012 ◽  
Vol 166-169 ◽  
pp. 414-419
Author(s):  
Li Hua Chen ◽  
Fei Xiao ◽  
Qi Liang Jin
Keyword(s):  
Composite Beam ◽  
Bending Moment ◽  
Longitudinal Shear ◽  
Structural Features ◽  
Composite Beams ◽  
Steel Beam ◽  
Negative Moment ◽  
Key Issues ◽  
Negative Bending ◽  
The Moment

Based on the theoretical analysis and testing results, some key issues in design of outer-plated steel-concrete continuous composite beams are discussed. The influence of the form of steel beam upper flange on the behavior of composite beam is analyzed. The requirements about longitudinal reinforcement strength in the concrete flange of the negative moment region are given. It is suggested that the moment-shear interaction should be neglected when calculating the flexural capacity of outer-plated steel-concrete composite beams under negative bending moment. The behavior of longitudinal shear resistance at the interface between the concrete flange and web of composite beam is studied, and the related calculating formula is put forward based on the structural features of the composite beam.

Study on Crack Resistance of Steel Fiber Reinforced Self-Stressing Concrete in Old Bridge Reinforcement

2008 ◽  
Vol 400-402 ◽  
pp. 543-548
Author(s):  
Bo Xin Wang ◽  
Cheng Kui Huang
Keyword(s):  
Crack Resistance ◽  
Steel Fiber ◽  
Bending Moment ◽  
Theoretical Models ◽  
Internal Force ◽  
Fiber Reinforced ◽  
Conventional Concrete ◽  
Continuous Beams ◽  
Negative Moment ◽  
Negative Bending

Steel Fiber Reinforced Self-stressing Concrete (SFRSSC) is a new type of fiber reinforced composite material. It has various applications in civil engineering for its well known superior properties such as self-expansive performance and high tensile resistance. However, it is not widely accepted as an effective reinforcement in the rehabilitation of the old bridges at present. The primary goal of this research is to apply SFRSSC to improve the crack resistance in the negative bending moment areas of the old bridges. Firstly, a computer analysis on the internal force of the continuous T-beams with 5 spans is given in this paper. The results show that the expansive action of SFRSSC can effectively decrease the internal force in the negative bending moment area. Meanwhile, based on the experiments of 5 composite concrete inverted T-beams, the crack resistance of the beams reinforced with SFRSSC layers is investigated. The test results obviously indicated that the composite layers enhanced the cracking moments 44.9% more than conventional concrete layers, though its height is only 13.9% of the cross section height. It is concluded that the continuous beams strengthened by SFRSSC has greatly improved the crack resistance in negative bending moment areas compared with the continuous beams strengthened by conventional concrete. According to the existing theoretical models, a procedure how to determine the self-stress is supplied and a formula which evaluating the crack resistance of composite T-beams in negative moment area is deduced in order to supply references to the old bridge rehabilitation design.

scholarly journals Experimental Study on Fatigue Performance of Negative Bending Moment of Steel-Concrete Continuous Composite Box Girder

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Pu Gao ◽  
Kuan Li ◽  
Yuanxun Zheng
Keyword(s):  
Concrete Slab ◽  
Bending Moment ◽  
Composite Beams ◽  
Fatigue Tests ◽  
Reinforcement Ratio ◽  
Fatigue Performance ◽  
Fatigue Load ◽  
Shear Connection ◽  
Negative Moment ◽  
Negative Bending

The experimental work presents results on the fatigue performance of composite beams in the negative moment region and the changes of stiffness and deformation of composite beams under repeated loads; fatigue tests were carried out on two double-layer composite beams. The fatigue performance of composite beams with different reinforcement ratios under complete shear connection and the variation of deflection, strain of the reinforcement, strain of steel beam, and crack growth under fatigue load were obtained. The results showed that the fatigue resistance performance of concrete slab with low reinforcement ratio was much lower than that of concrete slab with high reinforcement ratio whereas, under the fatigue load, the stress of the welding nail in the negative moment region was small and the slip was almost negligible. The degradation of stiffness and the development of cracks were mainly due to the degradation of bond-slip between the concrete and reinforcement. The fatigue failure mode was the fracture of the upper reinforcement in negative moment region. The results obtained in this study are helpful in the design of composite beam.

scholarly journals Experimental and Numerical Studies on the Negative Flexural Behavior of Steel-UHPC Composite Beams

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xinhua Liu ◽  
Jianren Zhang ◽  
Zihan Cheng ◽  
Meng Ye
Keyword(s):  
Crack Width ◽  
Bending Moment ◽  
Composite Beams ◽  
Flexural Behavior ◽  
Element Analysis ◽  
Conventional Concrete ◽  
Bond Slip ◽  
Cracking Performance ◽  
Negative Moment ◽  
Negative Bending

The cracking of concrete in the negative moment region for a composite beam subjected to a negative bending moment reduces the beam’s strength and stiffness. To improve the cracking performance of composite beams, this paper presents an experimental investigation on applying ultrahigh-performance concrete (UHPC) instead of conventional concrete. Three steel-UHPC composite beams with different forms of joints were designed and tested through a unique rotation angle loading method using a spring displacement control testing setup. The crack distribution, rotation versus crack width, load versus spring displacement, and strains in the UHPC slab and steel girders were measured and studied. Nonlinear finite element analysis using ABAQUS based on the damaged plasticity model of concrete was carried out for comparison with the test results. The experimental and numerical results showed that the use of a UHPC slab can enhance the cracking performance of composite beams. Considering the convenience of construction, a reasonable joint form was suggested, and the appropriate UHPC longitudinal laying length in the negative moment region was proposed to be 0.1 L. Furthermore, a simplified formula for calculating the UHPC crack width was developed based on bond-slip theory.

Model Test of Steel-Concrete Composite Beam Deck under Negative Moment

2021 ◽  
Vol 871 ◽  
pp. 340-348
Author(s):  
Rui Rong ◽  
Yu Hui Shan ◽  
Li Zhao ◽  
Bao Qun Wang
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Model Test ◽  
Composite Beam ◽  
Bending Moment ◽  
Cable Stayed Bridge ◽  
Composite Girder ◽  
Force Transfer ◽  
Negative Moment ◽  
Negative Bending

In order to understand the mechanical properties and force transfer law of steel-concrete composite beam deck under negative bending moment, and further guide the design. Based on a steel-concrete composite girder cable-stayed bridge, the model test of the mechanical behavior of the steel-concrete composite girder deck under the action of negative moment was carried out. The characteristics of mechanical failure and mechanical properties were analyzed.

scholarly journals The effect of flexural–torsional buckling on the stability of timber members: a case study

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Osama A. B. Hassan
Keyword(s):  
Axial Compression ◽  
Bending Moment ◽  
List Type ◽  
Torsional Buckling ◽  
Solution Methods ◽  
Simplified Solution ◽  
The Stability ◽  
Flexural Torsional Buckling ◽  
Building Engineering

Abstract This study investigates the stability of timber members subjected to simultaneously acting axial compression and bending moment, with possible risk for torsional and flexural–torsional buckling. This situation can occur in laterally supported members where one side of the member is braced but the other side is unbraced. In this case, the free side will buckle out of plane while the braced side will be prevented from torsional and flexural–torsional buckling. This problem can be evident for long members in timber-frame structures, which are subjected to high axial compression combined with bending moments in which the member is not sufficiently braced at both sides. This study is based on the design requirement stated in Eurocode 5. Solution methods discussed in this paper can be of interest within the framework of structural and building Engineering practices and education in which the stability of structural elements is investigated. Article Highlights This case study investigates some design situations where the timber member is not sufficiently braced. In this case, a stability problem associated with combined torsional buckling and flexural buckling can arise. The study shows that the torsional and/or flexural–torsional buckling of timber members can be important to control in order to fulfil the criteria of the stability of the member according to Eurocode 5 and help the structural engineer to achieve safer designs. The study investigates also a simplified solution to check the effect of flexural torsional buckling of laterally braced timber members.

scholarly journals Effects of Maximal Sodium and Potassium Conductance on the Stability of Hodgkin-Huxley Model

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yue Zhang ◽  
Kuanquan Wang ◽  
Yongfeng Yuan ◽  
Dong Sui ◽  
Henggui Zhang
Keyword(s):  
Experimental Data ◽  
Mathematical Method ◽  
Bifurcation Point ◽  
Potassium Conductance ◽  
Maximal Conductance ◽  
Computing Model ◽  
The World ◽  
Stability And Bifurcations ◽  
The Stability ◽  
Sodium And Potassium

Hodgkin-Huxley (HH) equation is the first cell computing model in the world and pioneered the use of model to study electrophysiological problems. The model consists of four differential equations which are based on the experimental data of ion channels. Maximal conductance is an important characteristic of different channels. In this study, mathematical method is used to investigate the importance of maximal sodium conductanceg-Naand maximal potassium conductanceg-K. Applying stability theory, and takingg-Naandg-Kas variables, we analyze the stability and bifurcations of the model. Bifurcations are found when the variables change, and bifurcation points and boundary are also calculated. There is only one bifurcation point wheng-Nais the variable, while there are two points wheng-Kis variable. The (g-Na,  g-K) plane is partitioned into two regions and the upper bifurcation boundary is similar to a line when bothg-Naandg-Kare variables. Numerical simulations illustrate the validity of the analysis. The results obtained could be helpful in studying relevant diseases caused by maximal conductance anomaly.

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