bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on Shear Behavior of Prestressed Concrete Deep Beams with Draped Tendons
Authors: Wang Guo Lin , Meng Shao Ping
Published: December 2010

Two simply supported deep beams were tested, one with draped prestresssing tendons and the other without for reference. Shear behavior and the prestressing effect were focused on. The test results showed that deep beams with the longitudinal reinforcement ratio of a normal amount were inclined to fail in flexural-shear, and the prestressing could greatly increase both the cracking load and the shear strength. Beside, the Modified Strut-and-Tie Model (MSTM) and the sectional design method from China Code (GB02) have also been adopted for predictions. The comparisons indicates that the MSTM can not only well predict the shear strengths of deep beams, but also well account for the prestressing effect, while the sectional design method seems so conservative due to its not properly considering the shear mechanism of deep beams. It can be concluded that the MSTM is capable of predicting the shear strength of PC deep beams with draped tendons and thus can be employed in practical designs.
Mechanical Behavior of the Slab on Prestressing Tendons Concentrated Arranged along the Columns
Authors: Yao Rong , Liang Heng Hong , Zhu Ping Hua
Published: December 2010

The internal-force distributing of the slab computed according to the existing design methods is different from that of the bidirectional slab supported on beam. The mechanical characteristic of the slab on unbonded prestressing tendons concentrated arranged along the columns is analyzed. The results show that the hidden beams of prestressing tendons couldn’t replace the role of the actual beam. Therefore, the prestressing tendons layout in the beam-less slab should not be disposed according to the internal stress distribution of the two-way slab supported on actual beams. Based on the FEM, a accurate method for calculating the amount of two-way prestressing tendons is put forward according to the bearing counterforce that existe in beam-supported two-way slab. The linear of the prestressing tendons is deduced and reasonable value of the equivalent load of prestressed tendons is suggested.
Numerical Simulation for Failure Modes of Reinforced Concrete Beams under Blast Loading
Authors: Zhang Xiu Hua , Wu Yan Yan , Wang Jun
Published: December 2010

The reinforced concrete (RC) beams have three failure modes using large-scale finite element procedure LS-DYNA to simulate dynamic responses and failure modes of RC beams under blast loading. Holmquist-Johnson-Cook material model was used in concrete, the damage and strain rate effects were considered the kinematic hardening plasticity material model was used in reinforcing bars. With different rebar ratios and charges of weight TNT equivalent and stand-off distance were investigated and discussed. The numerical simulation can predict responses and flexure, flexure-shear and direct shear of the RC beams under different blast loading. The influence of the several factors have been identified and provided a theoretical basis for blast resistant design and retrofitting of the RC beam.
Beam-Shell Compound Finite Strip for the Elastic Stability Analysis of Multi-Trough Rectangle Aquedcut
Authors: Xu Wei , Huang Liang , Wang Bo
Published: December 2010

A mathematical model using the beam-shell compound finite strip method is established to study the elastic stability analysis of multi-trough rectangle aqueducts. The impacts of the transverse stiffeners and crossbars for the model are taken into account. The principle of minimum potential energy is used to deduce the eigenvalue equation for elastic stability problems. To verify the accuracy and efficiency of the beam-shell compound finite strip method, the numerical solution of the stability analysis for an actual aqueduct is calculated through the established model and other FEM methods. The result of the stability analysis for an actual aqueduct shows that: the buckling coefficient is reduced as the water level increasing while buckling mode remaining constant; and prestressed load has a great impact on not only the buckling coefficient but also buckling mode.
Models of Aqueducts with Different Height-Width Ratio on Rigid Buttress
Authors: Leng Fei , Fu Dong Wang
Published: December 2010

Modified Housner model is presented in the paper for seismic analysis of aqueducts on rigid buttress. Invective mass is attached to walls of aqueducts rigidly instead of springs with low stiffness, which ensures vibrating frequencies can be computed. The coefficient α of invective mass is introduced to adjust the enlargement brought by the rigid attachment. The value of the efficient for aqueducts with different height-width ratio is determined by tentative calculation. Modified Housner model inherits the merit and avoids shortcoming of conventional Housner model. Finally the modified model is verified by an example and the accuracy of the model is proved to meet requirement of practical seismic analysis.
Effect of Pier Vertical Deformations on Deflections of Main Girders for High Pier and Long-Span Continuous Rigid-Frame Bridges
Authors: Du Jin Sheng , Liu Hai Bin
Published: December 2010

In some long-span prestressed concrete box girder bridges, excessive deflections of main girders are often observed. These unacceptable deflections have detrimental influence on the serviceability and safety of the structures. To better understand and estimate short term and long term deflections for prestressed concrete box girder bridges, pier vertical deformation and its effect on deflections of main girders of Jinghe Bridg is investigated in this paper. Piers in Jinghe Bridge are tall and the difference in height between piers up to 22 m. Analysis indicates that although the short term deformations of piers are small, the long term deformations of piers can be 3 times as large as that of short-term ones. The maximum short-term downward deflection of Jinghe Bridge caused by pier deformation for main girders is 7.7 mm and the maximum long-term downward deflection is 33.3 mm. These values are relatively small compared with the span length of the bridge. But when the deflection of the main girder itself is also included, the final total deflection of the main girder may exceed the design code limit.
The Experimental Research of Carbon Fiber Confined Concrete Considering Strain Rate under Uniaxial Compression
Authors: Zhang Yu Min , Su You Po , Su Jing Yu
Published: December 2010

In the three kinds of constraint ratio (ξ = 0.065, ξ= 0.1025, ξ= 0.205), respectively, by the comparative analysis of 55 prism specimens using CFRP confined concrete(strain ratses are 10-5/s-1, 10-4/s-1, 10-3/s-1and 10-2/s-1), the stress-strain curves, strength, strain, elastic modulus and Poisson's ratio were studied at different constraints and different strain rate. The results show that: (1) with the strain rate increased,the inflexion strength and ultimate strength of concrete were improved; (2) with the strain rate increased, the static and dynamic elastic modulus increased slightly; (3) Poisson's ratio increased slightly with the growth strain rate.
Three Dimensional Simulation of Steel-Concrete Composite Beams with an Interface-Slip Model
Authors: He Shi Qin , Li Peng Fei , Shang Feng
Published: December 2010

This paper presents a three-dimensional finite element (FE) anaytical approach for the simulation of steel-concrete composite beams. To simulate key problem, the interfacial behavior between the steel girders and concrete slabs, an interface-slip model is applied in the analysis. Both simple-supported beam experiment and continuous composite beam experiment are simulated. The load-deflection relation and the slip between the steel girders and concrete slabs as well as the strain of the steel girder and reinforcing bar in concrete are obtained from the FE analyses, and found to match well with the corresponding experimental results. The proposed nonlinear FE analysis method is capable of simulating the mechanical behaviors of steel-concrete composite beam.
Non-Linear FEM Analysis of Steel Fiber Reinforced Concrete Shearwall
Authors: Zhao Jun , Wang Li Jun , Gao Dan Ying
Published: December 2010

The numerical simulation by nonfinear finite element method(FEM) was adopted to analyze the behavior and the influences of the fraction of steel fiber by volume fraction and the strength of steel fiber reinforced concrete on the bearing capacity and the ductility of reinforced concrete shearwalls. The results show that with the increase of the fraction of steel fiber by volume fraction, the bearing capacity and ductility coefficient of steel fiber reinforced concrete shearwalls increase gradually. With the increase of the strength of steel fiber reinforced concrete, the bearing capacity and ductility coefficient of steel fiber reinforced concrete shearwalls decrease. It proves the rationality of the unit type, stress-strain relation of material and failure criteria used in the finite element analysis model.
Effect of Curvature Radius and Transverse Distribution of Load on Shear Lag for Curved Box Girders
Authors: Li Chang Feng , Du Wen Xue
Published: December 2010

Based on fundamental theory and variational principle of thin-walled curved beam and taking into account of coupling effect of bend and shear lag, the paper mainly discusses the variation of curvature radius and the transverse distribution of load in order to analyze effect of shear lag in curved box girder. By means of variational method, the paper derivates the elastic differential equation and boundary conditions and gives numerical results of equations finally, results are obtained by the Galerkin method. It shows that the curvature radius and the transverse distribution of load in the shear lag of curved box girder is very important by comparing the calculating results.
Study on the Influence Factors of Bearing Capacity of the Fiber Reinforced High Strength Concrete Three-Pile Caps
Authors: Lei Jie , Gao Dan Ying , Fan Hua
Published: December 2010

Based on the experiments of 10 model specimens of fiber reinforced high strength concrete three-pile caps with the dimension of 831mm×831mm×831mm, the mechanical behavior and the important factors on the cracking load and ultimate bearing capacity of fiber reinforced high strength concrete three-pile caps were researched. The study indicates that with increasing of concrete strength, the volume fraction of steel fiber, the effective thickness and reinforcement ratio of pile cap, the bearing capacity of three-pile caps improves largely. At the same time the type of steel fiber and steel ratio have remarkable effects on the bearing capacity. The results are valuable for establishing bearing capacity calculation formulas of fiber reinforced high strength concrete three-pile caps and improving “the Technical Specification for fiber Reinforced Concrete Structure.”
Research of Calculation Methods for Zero Block of Continuous Beam and Continuous Rigid Frame Bridges
Authors: Li Wen Hua , Zhai Xiao Liang , Qi Dong Yan
Published: December 2010

In order to optimize the zero block analysis method of continuous beam and continuous rigid frame bridge and provide better service for zero block design, a research for size of geometric model, pre-stressing simulation method, loading method and boundary conditions simulation was made. Some useful approaches for zero block calculation were presented through a lot of variable parameter analysis. A method considering the effect of reinforcement ratio was suggested to further judge calculation results of zero block three-dimensional finite element model (FEM). The results showed that the recommended zero block optimal calculation method has high practical value.
Dynamic Mechanical Response Validation of Pavement Structural under Complex Stress State
Authors: Qian Guo Ping , Li Shuai , Jiang Li Jun
Published: December 2010

Under the heavy traffic, the stress state of asphalt pavement structure has such a complex change that it is difficult for conventional pavement structural response calculation model to deal with. Therefore, "Pavement structure dynamic mechanical response model under complex stress condition" is established in this paper. Kinds of cases are calculated according to the characteristics of heavy vehicle. Then the FWD deflection test and dynamic strain test are carried out. Finally, the rationality of pavement structural response model calculation model is proved by comparing the test results with the theoretical model calculation results.
The Study on Implified Calculation of Cracking Torque of Steel Reinforced Concrete Combined Force
Authors: Liu Ji Ming , Zhou Fei , Zheng Jie , Xing Xiang Yang
Published: December 2010

Based on a steel reinforced concrete composite post crack under the torque simplified calculation method was studied. Using the simplified formula derived for H steel reinforced concrete structures under the action of compound and cracking torque is calculated. And simplify the calculation compared with the experimental value. The result is calculated with the testing results.
Experimental Study on Interface Shear Capacity of Reinforecd Concrete
Authors: Wang Wei , Su Xiao Zu , Zhao Yong
Published: December 2010

Nine push-off specimens were designed, constructed, and tested. Test variables included reinforcement ratio of shear reinforcement, interface preparation, loading method and eccentricity of applied load. The failure pattern, hysteretic characteristic and degradation characteristic of capacity and stiffness of the specimens were analyzed. The effects of moment and cyclic reversed loading on interface shear capacity were studied. The results indicated that applied moment less than or equal to the flexural ultimate moment of shear plane has little influence on the interface shear capacity, and the effect of cyclic reversed loading on the interface shear capacity of new and existing concrete is bigger. The test value and the calculated value of current Code and Specification of China were compared. Results showed that the current JGJ 1-91 interface shear capacity provisions gave a very conservative estimate for interface shear capacity, while for the new and existing concrete interfaces under the action of cyclic reversed loading, the calculated value according to GB 50010-2002 tended to be unsafe.
Nonlinear Stability Analysis of Qijiadu Long-Span Deck-Type CFST Arch Bridge
Authors: Xu Liang , Wu Ya Ping
Published: December 2010

With the application of the composition material-concrete-filled-steel-tube (CFST) in civil engineering, the crossing ability of arch bridge gets advanced development. Therefore, it is of interesting to study the stability of such long-span arch bridges, especially which have small width, for the bridge’s safety under long term operation. The present study focuses on studies the transverse stability of long-span arch bridges with small width. To this purpose, a deck type CFST arch-bridge in Gansu Province is adopted as an example. The arch bridge has a span of 180 m, and its width-span ratio is 1/25.7. The finite element method with a special beam element is employed to analyze the stability. The analyses are carried out for the transverse stability of the bridge during construction and under service, respectively. Furthermore, the influence of the spandrel structure and deck elastic restraints to the stability is investigated taking account of geometrical and material nonlinearity.
Effect of Openings on Elephant’s Foot Buckling of Large Oil Tanks
Authors: Chen Zhi Ping , Yan Shun Juan , Yu Chu Lin , Cao Guo Wei , Wang Lei , Yang Li Cai
Published: December 2010

Large non-anchored welded steel oil tanks are important equipments that are renowned for their extremely large structures, they are vulnerable to elephant’s foot buckling failure which can cause serious damages in seismic. Generally, locations of tank openings are at the first layer of shell course which are just close to elephant’s foot buckling position of oil tanks. While learning the effect of openings on elephant’s foot buckling of oil tanks, the welding residual deformation was assumed to be initial geometric imperfections. Numerical simulation method was adopted to analyze the effect of three factors (oil tanks with or without openings, opening sizes and opening positions) on elephant’s foot buckling critical load of oil tanks. Results show that the openings and reinforcement plates are beneficial to the increase of buckling critical load; the size and location of the openings have little effect on the buckling critical load.
Calculation of Incremental Force of External Steel in Simply Supported Externally Prestressed Beams
Authors: Hu Di , Yu Zhi Wu
Published: December 2010

Considering the relationship of displacement and turn angle in anchorages and deviators between the externally prestressed steel and concrete beam under the action of load in simply supported externally prestrressed beam, equations on solving the incremental force in externally prestressed steel are established. The presented novel approach and the train of thought can be easily extended to analyze time-dependent effect for externally prestressed beams. The example shows that the theoretical values based on the presented formulae are agreeable with the results obtained by other methods.
Bilateral Shear Strength of Rectangular Frame Column with Different Stirrup on Two Principal Axis
Authors: Dong Chun Min , Jin Lian , Jia Sun
Published: December 2010

To study bilateral shear strength of rectangular frame column (RFC) with different stirrup area on two principal axis, 12 rectangular frame columns including 5 columns without stirrup and 7 columns with stirrup were tested. The analytical results indicated that the relationship of shear strength between two principal axes of RFC without stirrup could be approximately described as ellipse, and stirrup stress on two principal axes is independent. The oblique shear strength is less than the resultant force calculated by unilateral shear strength formula offered by Code for Design of Reinforced Concrete Structure. The reason for this is shear strength contributed by concrete is considered iteratively on two axes. Based on truss model and the above conclusion, a reduced coefficient is introduced to calculate the bilateral shear strength offered by concrete and the axial force, and then a formula is proposed to calculate bilateral shear strength of RFC with different stirrup area on two principal axes. Comparison between the calculation and experimental results shows the formula is feasible and safe.
Development of the Stress-Strain Relationship for Crack Diffused Concrete
Authors: Li Yan Ru
Published: December 2010

On the basis of diffusion mechanism of crack and stress-strain of concrete, the mathematical differential formula and the pure theoretical model of stress-strain complete process of concrete are established. It is shown that stress-strain relationship of concrete is affected by Hooke’s law and diffusion mechanism of crack, and the law of which can be expressed by an exponential formula.
Test Research on Spatial Hysteretic Behavior of Circular Steel Pipe
Authors: Nie Gui Bo , Zhi Xu Dong , Fan Feng
Published: December 2010

A test to study the spatial hysteretic behavior of circular steel pipe subjected to cyclic load was designed. The test setup and data acquisition system were applicable for three-dimension load. A total of 30 specimens were selected by cross section and height of the circular steel pipe to cover different slenderness ratios, different load modes. The specimens were divided into five groups by different load modes. The hysteretic curves changing with different slenderness ratios and different load modes were got after completing the experiment. These lay the foundation of the subsequent research on constitutive model about steel.
Structural Assessment of a 40 Year Old R.C. Building
Authors: Bsisu Khair Al Deen Isam
Published: December 2010

A 6-story R.C. office building had a plan typical of a frame design, but a beam column design procedure was used. Working Stress Design method was used. Severe cracking ranging in size from 5 – 20 mm. A comprehensive study of the design drawings, site and laboratory testing was conducted on structural members to determine the cause and suggest the remedy.
Calculation of Ductility of Square CFT Stub Columns with Binding Bars Subjected to Eccentric Load
Authors: Su Guang Qun , Cai Jian , Zhao Xiao Qin , Zhu Chang Hong
Published: December 2010

Based on the equivalent uniaxial stress-strain relationship for the encased concrete in the square steel tube with binding bars, the ﬁber element analysis technique is used to conduct the load versus curvature curves for the square concrete-filled steel tubular (CFT) stub columns with binding bars subjected to eccentric load, and the results predicted by the program agree well with the experimental ones. The ﬁber element analysis program developed is then used to investigate the effects of varied parameters on the curvature ductility of square CFT stub columns with binding bars subjected to uniaxial or biaxial eccentric load, and the corresponding simplified formulas to predict the curvature ductility of the columns are put forward, respectively. The results predicted by the simplified formulas agree well with those predicted by the program.
Experimental Study on Structural Performance of a Novel Integral Noise Barrier for Urban Rail Transit
Authors: Gao Peng , Zhang Ji Wen , Tu Yong Ming
Published: December 2010

A novel integral noise barrier (INB) composed of steel fiber reinforced cementitious composite (SFRCC) and basalt fiber reinforced plastic (BFRP) is put forward in this paper. Compared with traditional noise barrier, INB integrated sound-absorbing panel, H type steel, autoclaved lightweight concrete (ALC) bridge guardrail panel into a whole. The basic design idea and experimental method for INB are described. Based on the engineering demand for eastern extension project of the No.2 subway line of Nanjing, six specimens were cast and tested under simulated positive and negative loads. Under the design loads, six specimens did not crack and the lateral displacement on the top of the slab is less than H /250, where H is the height of INB. The experimental results show that INB can meet the design requirements of eastern extension engineering of the No.2 subway line of Nanjing.
Finite Element Analysis of Ultimate Load-Carrying Capacity of CFST-CSW Arches
Authors: Gao Jing , Chen Bao Chun
Published: December 2010

In order to better understand the behavior of CFST-CSW arch, experiment on two hingeless CFST-CSW arches are described in this paper, subjected to in-plane symmetrical and asymmetrical loading respectively. The experiment yield important information regarding the manifestation of the limit state and also afford an opportunity to verify finite element modeling techniques for use in a parametric study. The parametric study reveals that the load-carrying capacity is influenced by many factors including the rise-to-span ratio, slenderness ratio, loading cases and material properties.
Applicability Study on Method of Stability Analysis for Suspendome Structures
Authors: Shi Kai Rong , Jiang Zheng Rong , Wang Shi Tong
Published: December 2010

Consistent Mode Imperfections Method based on eigenvalue buckling mode is widely adopted in the stability analysis for the spatial steel structures with initial geometrical imperfections, i.e. latticed shells, thin shells, etc. Taking the new type hybrid structure of suspendome as the analytical object, the applicability of Consistent Mode Imperfections Method is discussed. The effects on structural stability are probed arisen by the factors such as different initial reference loads and different order eigenvalue buckling modes. It is indicated that this stability analysis method can be quite fit for the spatial structures such as latticed shells, while for suspendomes, the initial reference load has a distinct effect upon the analytical result obtained by the stability analysis method. Moreover, it is not always to dominate calculating result when selecting the first order eigenvalue buckling mode as the distributing pattern of initial geometrical imperfections. As a result, some measures should be taken to improve the accuracy in evaluating the stability bearing capacity of the structures with Consistent Mode Imperfections Method based on eigenvalue buckling mode.
Multi-Tower Effect Analysis of Long-Span Suspension Bridge
Authors: Zheng Xiao Yan , Feng Zhuo De , Xu Yue
Published: December 2010

As a new bridge system, mechanics behavior study on long-span multi-tower suspension is also very deficiency. The existence of center towers is the origin of performance difference between multi-tower suspension bridge and the traditional one. Based on the Midas/Civil platform, the paper takes a three tower suspension bridge as project reference, establishes finite element models of suspension bridge, which the main span is longer than one kilometer and towers from two to seven. Moreover, the structural property is analyzed separately, which bending moment and displacement effect of girder and tower along with the tower number changes is considered. Natural frequency differences of the model bridges are also paid attention on.
Wrinkling Analysis of Stiffness Equivalence in Membrane Structures
Authors: Zhao Ran , Wei De Min
Published: December 2010

Based on the tension field theory, a wrinkling analysis method of equivalent stiffness was proposed. The new method was derived and the feasibility was theoretically proved. And a membrane structure was analyzed by the method. The results show that the correct load responses could be quickly attained right after appearance of wrinkled elements, which indicate that the method can be applied to wrinkling analysis of membrane structures.
Creep Stress Analysis of PC Composed Box Girder Bridge with Corrugated Steel Webs
Authors: Shan Cheng Lin , Yan Ling
Published: December 2010

According to the forced load-bearing characteristics of the prestressed concrete girder bridge with corrugated steel webs, the cross-section internal forces and stress redistribution of box-girder were studied under the influence of concrete creep. And the internal force redistribution formula on concrete creep was derived through the establishment of the compatibility equation of bending deformation; the stress redistribution formulas of the top slab and the bottom slab of box-girder at any time were also derived, through the establishment of the compatibility equation of the axial displacement and angular deformation of the top slab and the bottom slab of box-girder under the influence of concrete creep at any time. These show that the creep stress is only related to the box height and it’s the geometric properties of top slab and bottom slab concrete section, but not to the steel web’s size.
Preparation and Properties of PS/PSMA/EG Composite Materials
Authors: Hou Gui Xiang , Liu Sheng Yuan , Sang Xiao Ming
Published: December 2010

Polystyrene (PS)/Poly(S-co-MA)/expanded graphite(EG)(PS/PSMA/EG) nanocomposites were prepared by melt blending, using a variety of PSMA/EG.. The electrical and mechanical properties of the PS/PSMA/EG were measured. Mechanical property measurements of composites indicated higher impact strength and lower tensile strength with increasing concentration of PSMA/EG. Exfoliated graphite has seen a significant reduction for composites in electrical resistivity.
Finite Element Analysis of Mechanical Behavior of Light-Weight Mobile FRP Bridge
Authors: Huang Xin , Mu Zai Gen , Feng Peng
Published: December 2010

As composite materials have advantages of high strength-to-weight ratio and superior corrosion resistance properties, it is used in emergencies in the construction of mobile bridges as the preferred material. However, In contrast to traditional steel or aluminum to the movement of the bridge as the main material, the original bridge forms need to be improved in order to reach the full of FRP material properties. In this paper, to study the domestic light-weight mobile FRP Bridge, the finite element method is used to analysis the mechanical properties of bridge.
Experimental Verification on Bearing Capacity of Concrete-Filled Steel Tube Short Columns Based on Unified Theory
Authors: Ji Jing , Zhang Wen Fu , Sui Hai Yan
Published: December 2010

To verify the rationality of calculation method on unified theory of concrete - filled steel tube short columns under axial force, Experimental Study on mechanical properties of the 12 concrete -filled steel tube short columns with 7 different sections under axial force is preformed. Failure process and Failure mode of them are observed, load-displacement curves are obtained, and the influence for confinement coefficient ξ to the mechanical properties of short columns under axial load is analyzed. Based on load-displacement curves, ultimate bearing capacities of them are given. By comparison for ultimate bearing capacity obtained by testing and the bearing capacity according to unified theory, the results show both are in good agreement. Calculation method on unified theory of concrete - filled steel tube is fit for calculating ultimate bearing capacity of short columns under axial force with different sections, and the results are safe and reliable.
Analysis of Long-Term Stress of Steel-Concrete Composite Beams
Authors: Ding Min , Ju Jin San , Jiang Xiu Gen
Published: December 2010

The theoretical model to compute long-term stress of steel-concrete composite beam was deduced. On this basis, the effects of factors such as concrete age to loading, longitudinal reinforcement ratio in concrete slab, concrete slab width, environmental yearly average relative humidity and concrete strength on long-term stress of composite beams are discussed. The results show that additional stress at the top of concrete slab is tensile stress and that at the bottom of steel beam is compressive stress. Concrete slab width, as well as longitudinal reinforcement ratio can not be ignored. Concrete strength and concrete age to loading have relatively bigger effect as well. But environmental yearly average relative humidity has less impact.
The Constitutive Relationship of Concrete Core in Circular Concrete-Filled Steel Tubular Columns
Authors: Liu Lin Lin , Tu Yong Qing , Ye Ying Hua
Published: December 2010

Considering the confining mechanism in circular concrete-filled steel tubular (CFST) columns, a volume-based method for dividing the effectively and ineffectively confined area of concrete core and calculating the value of effectively confined coefficient is presented. The constitutive relationship of concrete core is developed by means of modifying the expressions of effective lateral pressure and the descending stage in Mander’s confined concrete model. Numerical simulation of several circular CFST columns under axial load is carried out in ABAQUS. The comparisons between calculated results and experimental results demonstrate that the suggested concrete constitutive relationship is appropriate for the nonlinear analysis of circular CFST columns.
A Robust Design of Suspenders in through and Half-Through Arch Bridges
Authors: Jiang Rui Juan , Wu Qi Ming , Chen Yi Yan , Cui Fei , Yi Xiao Wei
Published: December 2010

It is well-known that in modern through and half-through arch bridges the suspenders are important components since they connect the bridge deck and the arch ribs. The collapse of bridge deck or arch ribs may be induced once one or more suspenders are broken. In this paper, the traditional design way of the suspenders in through and half-through arch bridges is discussed first. Based on the discussion, a new way to design suspenders for arch bridges is then put forward. The reasonability and robustness of this new way is proved by a numerical example based on a real through arch bridge using the comprehensive commercial software ANSYS. It can be concluded from the analysis in this paper that the new way to design the suspenders for the through and half-through arch bridges can assure the safety of the bridge effectively even though one or more suspenders happen to break.
Sliding Response of Free-Standing Cultural Relics under Earthquakes by Simulation
Authors: Zhou Qian , Yan Wei Ming
Published: December 2010

To protect cultural relics,sliding response of free-standing museum cultural relic under earthquakes was studied by SIMULINK technique.By hypothesis that shape of cultural relic was rectangle, under earthquakes its sliding conditions were analysed,its motion equations were deduced, its response curves of displacement,velocity and acceleration were obtained,and parameters such as friction ratio between it and its base as well as peak earthquake acceleration values were discussed.Results show that slide motion of cultural relic relates mainly to friction ratio and earthquake strength;Its sliding response is more obvious with the increase of earthquake strength and decrease of friction ratio;On the other hand,by SIMULINK technique sliding response of free-standing cultural relic under earthquakes can be effectively simulated which proves the technique useful.
Research on Vibration Characteristics and Seismic Response of Shell of LNG Tank
Authors: Ji Jing , Yang Tao , Zhang Wen Fu , Chang Liang , Sui Hai Yan
Published: December 2010

Liquefied Natural Gas (LNG) tank is the important equipment in storage LNG. There has been a lot of research results abroad, but lack of seismic studies for the LNG tank in China. Domestic structural designers also have an urgent need for internal force and deformation law of LNG tanks under a variety of dynamic loads. This study focused on vibration characteristics and seismic response of a shell of LNG tank. Using ANSYS creat finite element model, obtain natural frequency and vibration mode etc. According to requirements of Chinese "code of building seismic design", analyze this shell of LNG tank of unidirectional horizontal seismic response under the action of selected three kinds of seismic waves. Time-history curves of LNG tank’s displacement, acceleration, stress distribution law under the action of selected three kinds of seismic waves are obtained.
Dynamic Response Analysis on Steel-Concrete Composite Frame Based on ETABS
Authors: Wu Yong He , Mu Jian Chun , Li Sheng Qiang , Xi Hui Feng
Published: December 2010

This paper is to make an elastic dynamic time history analysis on a steel-concrete composite structure under the effect of frequent earthquake. And it reveals the collaborative performance of steel frame and RC frame under the seismic motion effect by studying time history response of the parameters like base shear, base bending moment, structure top acceleration and displacement of the structures under the seismic motion effect. The results show that for the steel-concrete composite frame structure under the seismic motion effect, its maximum base shear, maximum bending moment, structure maximum top acceleration and maximum displacement do not occur at the same time, and dynamic response of the top steel frame acceleration, displacement and other parameters increase more significantly than the lower RC frame, while Steel-concrete composite structure may produce resonant phenomenon with earthquake vibration.
Damage Assessment of Single-Layer Cylindrical Latticed Shells Based on Degradation of Static Stability Capacity
Authors: Yang Da Bin , Zhang Yi Gang , Wu Jin Zhi , Zhou Hai Tao , Liu Wen Chao
Published: December 2010

The static stability capacity is the main index to measure the whole mechanical performance of single-layer latticed shells. Three single-layer cylindrical latticed shells with different height to span ratio were modeled, and their seismic damage were assessed by the degradation of static stability capacity incurred by earthquakes. Two different static load patterns were considered: dead load and the combination of dead load and half span live load. The results show that the damage assessment method is applicable to single-layer cylindrical latticed shells, and the static load patterns have no big influence on the damage assessment of the single-layer cylindrical latticed shells.
Effects of Stable Cable on Ultimate Load-Carrying Capacity of Long-Span Composite Girder Cable-Stayed Bridge with Three Pylons
Authors: Wang Long Fei , Liu Mu Yu
Published: December 2010

On the background of a long-span composite girder cable-stayed bridge with three pylons under construction for research, this paper establishes two models of the whole bridge by considering the structural geometric nonlinearity, material nonlinearity and interface slip effect in composite girder, one has stable cables between pylons but the other hasn’t, then comparatively studies the failure loads and structural internal forces of the two models to achieve effects of stable cable on the ultimate load-carrying capacity of the cable-stayed bridge. This research shows that the stable cables can strengthen the vertical stiffness of structure and obviously increase the failure load of the bridge, and the internal forces in main girder, middle pylon and stayed cables are smaller and their distributions are more reasonable under the failure load than those in the bridge with no stable cables, so the stable cables can effectively improve the ultimate load-carrying capacity of long-span composite girder cable-stayed bridges with three pylons.
Combined Shape and Topology Optimization of Free Form Shells
Authors: Wang Lei , Zhang Qi Lin , Yang Bin
Published: December 2010

With the aim of finding the optimum design that maximizes the stiffness of shell structures, an suitable approach for combined shape and topology optimization of free-form surface is presented. For numerical expression for the configuration of free form shell, NURBS (Non Uniform Rational B-Spline) is utilized. For shape optimization, the approach is employed to calculate the differential of total structural strain energy corresponding to surface height parameters. The surface height is adjusted iteratively according to its sensitivity to total structural strain energy. For topology optimization, the OC algorithms which are derived from the necessary optimality conditions are used and element connectivity is taken as design variable. The method has been implemented into a computational 3D model and example is provided to show the applicability of the present method.
Dynamic Response Analysis and Optimal Design of a RC Slab to Blast Loads
Authors: Sun Wen Bin
Published: December 2010

Current guidelines such as TM5 and ASCE use a trial and error procedure to design RC slabs against blast loads. Although the trial and error procedure is easy to implement, it may not result in a optimal to resist blast loads. In this study, SDOF system recommended by TM5 and ASCE was adopted to simplify RC slabs; the bilinear model was selected to simulate the resistance-deflection curve for dynamic response analysis. After comparing the areas under the resistance-deflection curves of RC slabs with different reinforcement ratios, the reinforcement ratio responding to the biggest area can be defined as the optimal reinforcement ratio. These derived relationships are useful to facilitate a design with maximum capacities to resist blast loads.
Shape Optimization and Seismic Design of Concrete-Filled Square Tubular Column and Reduced Beam Section with Cut Web
Authors: Guo Yan Li , Yao Xing You
Published: December 2010

According to anti-seismic design principle of strong column and weak beam, and of strong joint and weak member, reduced beam section(RBS) is often used to shift away plastic hinge from end of beam to weaken region of the beam. Reduced beam section with cut web are analyzed by non-linear finite element method(FEM) in this paper. Two kinds of effective suggested joints of reduced beam section(circled hole and long-circled hole) are put forward by comparing the results of mechanical behavior of reduced beam section with which of traditional RBS, including of ultimate load-carrying capacity, Von-mises stress distribution and the place of largest stress of beam end of the beam-column joints. A proposed seismic design method is put forward according to related chinese codes.
Research of Optimization Design on Floating Floor Insulation
Authors: Mao Jian Xi
Published: December 2010

In order to acquire a high quality of living environment, it is necessary to investigate the subjects of floor impact sound insulation. According to the characteristics of optimization design method and restricted optimization math model, the sound transmission between floor and adjacent room down through floating floor has been modeled in a finite-element method. Floating floor structure are studied to realize the design optimization when the room average sound pressures are selected as objective function. Predicted results show that when keep the whole thickness of floating floor fixed, result of dynamics optimization design can reduce room average sound pressure effectively. And when keep the whole thickness of floating floor unfixed, optimization results have been gotten on the total thickness of floor layer and resilient interlayer of the floating floor, and the average sound-pressure in room is lower than original one availably.
Multi-Target Optimization Design of Earthquake-Resistant Structure Taking Ductility and Cost into Account
Authors: Zhao Hong Sheng , Ji Hui
Published: December 2010

Using the conventional structural design methods, the design result is usually not the most economical and the most reasonable. While, using the single target structural optimization design method, duo to the only one target function to be optimized, the design result often can not meet with the multiple requirements of structural designing, furthermore its optimizing efficiency is low. So its application is limited. This paper proposes multi-target earthquake-resistant optimization design method for reinforced concrete frame structure under earthquake loading. In the optimization design approach, the ductility and cost which are two factors contradictory each other in structure designing are simultaneously taken as the target functions, and the function relation formula between them has been established, giving simultaneous consideration to the structural economy, safety and practicability. Using this design approach, the optimum cross-sectional dimensions, with the largest ductility and the lowest cost, of the reinforced concrete frame structure which is optimized under earthquake loading, can be obtained by computer. The practical examples of structure design, which have been optimized by using this approach, show that the cost of construction has been cut down by about 10% comparing with the conventional designing. The optimization process presented in this paper conforms entirely to the China national standards: “Code for Design of Reinforced Concrete Structures” (GB50010-2002) and “Code for Earthquake-resistant Design of Buildings” (GB50011). The theory and methods presented in this paper, having not only their theory meanings but their practical values, will be helpful for the structural design engineers and the researchers.
The Simulation and Analysis of Energy Saving with Compound Block Used Construction Waste
Authors: Chen Gang , Meng Dan , Fang Yong Lin
Published: December 2010

This article selects a typical compound block as the research object, which use construction waste and other solid waste as main raw material, and the finite element method is used to simulate. The temperature, thermal bridges and heat flux distribution of the block surface and interior, and drawn mainly thermal performance parameters are simulated and analyzed. Then the discussion on the block’s optimization and improvement was presented with the combined of simulation and experimental results, to improve its thermal performance and achieve better energy saving effect.
Structural Optimization Design of Rear Axle Housing Excited by Dynamic Load
Authors: Meng Qing Hua , Zhang Yan Ling , Yu Hong Shun
Published: December 2010

In order to obtain structural optimization design of rear banjo axle housing, a seven degree of freedom dynamic model of vehicle was presented. Based on the model, vehicle vibrating equations were presented. Random phase method was used to generate C grade road surface irregularity of time history that applied to vibrating equations to acquire dynamic load imposed on the banjo axle housing. A detailed CAD model of the housing was developed by using of UG software. The finite element model of the housing was built, and the stress and strain of the housing were obtained by using of ANSYS Workbench software. The mathematical model of optimal design was constructed and analyzed based on the result of finite element method. The optimization result shows that the weight of banjo axle housing can be reduced under satisficing the stress and strain condition that excited by dynamic load.
Delamination Patch Detection in FRP Composite with 3×3 Coupler Based Mach-Zehnder Interferometer
Authors: Xu Ying , Dong Bi Qin , Jiang Yi
Published: December 2010

A 3×3 coupler based Mach-Zehnder Interferometer is used for delamination patch detection in FRP composite. Mechanical tests are performed and the sensing arm of the interferometer is embedded along the neutral plane of the laminate. A quasi-impulse loading is applied and the total elongation of the embedded optical fiber is measured as a function of load position. When a delamination is present, the shift of neutral axis position can be clearly reflected in the fiber integral strain versus load position plot. Experimental results demonstrate the feasibility of detecting both the size and location of delamination patch with the proposed technique.
The Influence of Crack on the Dynamic Characteristic and Acoustic Radiation Characteristic of Gear Plate
Authors: Shao Ren Ping , Xu Zhi Feng , Ma Jie
Published: December 2010

The gear structure is equivalent to disposed as a circinal plate, and also, the root crack of gear are simulated by setting the radial direction crack. Because of the appearing of crack, it will divide the whole circinal plate into some areas, and set different polynomials of vibrational flexibility in every area, then using District Technology and Rayleigh-Ritz method, the dynamical characteristic of circinal plate with radial direction crack is analyzed, the influence of the size of crack on dynamical characteristic(natural frequency, modal shape etc.)of circinal plate are deep studied. On this basis, making use of Finite element method, the first some order mode of the acoustic character of cracked plate are investigated using discrete Rayleigh integral, and the distribution of sound pressure on the r=0.5m sphere surface is obtained. At the same time, the influence of the different depth of crack on acoustic characteristic of gear disc are discussed, and the rule of influence of crack on radiated acoustic field is given out. This result shows that the influence of crack on radiated acoustic field of circinal plate with the increase crack depth is increscent; moreover, with the increase in crack distance from the fixed end, the crack of plate increases the effect of the sound field. So, these provide a theoretic foundation for gear fault diagnosis using the dynamic and acoustic method in engineering.
Structural Damage Detection through Chaotic Interrogation and Attractor Analysis
Authors: Qiu Qun Hai , Xu Chao , Wu Bin
Published: December 2010

In this paper, a new approach for damage detection using a chaotic signal as an input excitation and steady state attractor-based measures as diagnostic parameters is investigated by means of numerical simulations. The method utilizes the deterministic, extreme sensitive properties of the chaotic signal to give rise to a low-dimensional response for feature extraction. This approach is applied to two numerical examples, the 4 DOF spring-mass-damper and a cantilevered beam system, where the damage is produced by varying the structural damping and stiffness, respectively. Lyapunov dimension is calculated as a “feature” for detecting the damage. Results show that this approach is feasible to detecting structural damage.