bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Restraining Stiffness on Mechanical Properties of Suspen-Dome
Authors: Guo Jia Min , Dong Shi Lin , Yuan Xing Fei , Hou Yong Li
Published: December 2010

Suspen-dome is a kind of large-span prestressed hybrid structure, To understand the influence of radial restraining stiffness to structural mechanical response, and to ensure radial restraining stiffness reliable during designing, a rib 3 type suspen-dome and corresponding single layer lattice shell were selected, their static response under different radial restraining stiffness were studied and compared .At the same time, basic dynamic properties of a rib 3 type suspen-dome were analyzed under different radial restraining stiffness. The results show that the sensitivity of single layer dome mechanical response to radial restraining stiffness will be reduced because of the bottom cable-struts, enhance of radial restraining stiffness will not influence structural mechanical response after radial restraining stiffness reaches certain value.
Experimental Study on Hysteretic Behavior for Plate-Reinforced Connections
Authors: Wang Yan , Feng Shuang , Gao Xiang
Published: December 2010

8 plate-reinforced connections are manufactured at 1/2 scale and then tested under low-cyclic loadings to study their hysteretic behavior, and numerical simultation with ANSYS are applied based on the experimental results. Failure patterns, energy dissipation, hysteretic behavior and skeleton curves are comparatively studied by changing the dimensions of the reinforced plates. Results show:(1)the plastic hinge be formed 1/3-1/4 beam depth from the end of reinforced plate and is obvious, there are serious local buckling in the flange and web, and there is no fracture in the beam-to-column welding;(2)The geometric parameters of reinforced plate have important effect to the bearing capacity and ductility of connections. With the increase of length and thickness of reinforced plate, the bearing capacity increases and hysteretic behavior and ductility factor decreases;(3)When the length of reinforced plate is bigger than the design requirements, there is brittle failure in the panel zone, which lead to decrease of capacity of energy dissipation and equivalent viscous damp coefficient;(4)Recommended parameter scope: the recommended length of reinforced plate(flange-plate and cover-plate) is defined as 0.5-0.8 times beam depth, the recommended thickness of flange-plate is 1.2-1.4 times flange and the recommended thickness of cover-plate is 0.7-1.2 times flange.
Effects of Titanium Microalloying on Steel Feeding and Contraction
Authors: Wang Hai Tao , Tan Ji Wen , Chu Zhong , Sheng Chun Yan
Published: December 2010

Proper content of titanium, microalloying in steel ZG200-400 smelted in intermediate frequency induction furnace, could effectively increase the volume of concentrated shrinkage cavity, and restrain the forming of shrinkage porosity. The concentrated shrinkage cavity was analyzed quantitatively by stuffing wet gluten and draining water method. The maximal cavity arrived at 0.18wt.% titanium microalloying. By scanning electron microscope (SEM) and energy disperse spectroscope (EDS) analysis, it was found that TiC, acting as heterogeneous nuclei, could refine the structure grains, diminish the strong dendrites, and increase the fluidity and feeding capacity of steel liquid. However, overdoes titanium microalloying easily caused mass nitrides or oxides, which kept solid phases with high meting point in metal liquid to increase its viscosity, decrease the fluidity and enlarged the composition supercooling. So the metal liquid, with poor feeding, left more shrinkage porosity, less concentrated shrinkage cavity in solidification.
Parameter Analysis of Compressive Web Members in Plane Tubular Truss with Simple Joints
Authors: Peng Xiao Tong , Zhang Qi , He Xi Xia
Published: December 2010

Stability design for compressive web members of tubular structure could be simplified as determination of effective length of compressive web members. There were no design provisions for effective length of compressive web members in tubular truss in the current design code of steel structure (GB50017-2003). Based on previous research achievements, parameter analyses on compressive web members in tubular truss with simple joints were performed using finite element software, in which diameter ratios and wall thickness ratios of web members to chord members as well as different construction styles were considered. After analyzing 3 series, sum to 42 FEM model, the results indicates that stiffness ratio of web members to chord members has a significant effect on effective length of compressive web members, thus increasing width ratio of chord members to web members could decrease effective length of compressive web members; the effective length of compressive web member in circular tube truss is suitable to be 0.75 in-plane and out-plane, and 0.8 for the mixed truss of circular and square tube.
Load-Carrying Capacity Estimation Methods for Cold-Formed Steel Lipped Channel Member Using Effective Width Method
Authors: Yao Xing You , Li Yuan Qi , Shen Zu Yan
Published: December 2010

Distortional buckling may occur for Cold-formed thin-walled steel lipped channel member except local buckling and overall buckling. The buckling of flange and lip are the important factor for the occurrence the distortional buckling. The different design codes have different design method for calculating plate buckling coefficient of flange and lip using the effective width method. So the effective width method in different codes are introduced and the load-carrying capacities of 100 lipped channel section compressive members collected from reference are computed using ‘Cold-formed steel structures (AS/NZS 4600:2005)’, ‘Supplementary rules for cold-formed members and sheeting(EN1993-1-3:2006)’, ‘North American specification for the design of cold-formed steel Structural Members(AISI-S100:2007)’, ‘Specification for the design of cold-formed steel structural members (AISI:1996)’ and ‘Technical code of cold-formed thin-walled steel structures’(GB50018-2002). The calculated results show that ‘Technical code of cold-formed thin-walled steel structures (GB50018-2002)’ and ‘Supplementary rules for cold-formed members and sheeting (EN1993-1-3:2006)’ are conservative and ‘Cold-formed steel structures (AS/NZS 4600:2005)’, ‘North American specification for the design of cold-formed steel Structural Members (AISI-S100:2007)’ and ‘Specification for the design of cold-formed steel structural members (AISI:1996)’ are unsafe. The elastic buckling stress of different lipped channel sections are predicted by finite strip program (CUFSM) and get the suggested calculation formula of plate buckling coefficient of flange according to regression Analysis. The calculated results using suggested plate buckling coefficient of flange are agree to test results.
The Elastic-Plasticity Analysis on Cross-Section Short-Limb Shear Wall
Authors: Zhang Qiang , Tao Cheng Cheng , Wei Chen Bing , Zhuang Jian , Tan Pei , Liang You Hai
Published: December 2010

The elastic-plasticity of ten cross-section reinforced-concrete short-limb shear wall specimens under monotonic load are analyzed by ANSYS, which compares the change of load capacity, stiffness and ductility of the shear wall when concrete strength grade and limb-length ratio change. The analysis results show that when concrete strength grade is C30, shear wall of this shape can be made with better performances in load capacity and deformation capacity, and when limb-length ratio is 0.6, the ductility and the ability of the energy dissipation of shear wall is not good, which provides a significant basis for practical engineering section design.
Deflection Analysis of Externally Prestressed Concrete Beam Based on Damage Mechanics
Authors: Xiong Hui Xia , Sima Yu Zhou , Zhang Yao Ting
Published: December 2010

This article describes the static experiment of externally prestressed concrete beam under the beeline reinforcing patterns. It adopts the damage mechanics - superimposed load - finite element method, uses damage constitutive equation to replace the constitutive equation, which does not take the damage into account, self-compiled eight-node uniform-parameter element superimposed load finite element program is used to analyze the forced distortion of experimental beam. The value analysis results show: the damage mechanics can soundly reflect the complicated behaviors of concrete materials in the load-superimposing process and has obtained the values of the concrete material damage characteristic parameters and achieved the results that are consistent with the experiment. Therefore, damage mechanics has provided a new way in studying the nonlinear behaviors of concrete materials.
Ultrasonic Propagation Characteristics and Damage Evolution of Recycled Concrete under Dynamic Loading
Authors: Luo Xing Wen , Yao Hai Lin
Published: December 2010

Four types of recycled concrete specimens were made for dynamic loading tests in laboratory, in order to research the ultrasonic propagation characteristics and damage evolution of recycled concrete under dynamic loading. Ultrasonic propagation parameters such as ultrasonic propagation wave time, ultrasonic velocity and ultrasonic amplitude of recycled concrete were tested synchronously while recycled concrete were loaded. Tests results show that ultrasonic propagation wave time increased with the rise of cyclic times, while ultrasonic amplitude decreased in the same time. Damage variable evolution of recycled concrete lived through obvious three stages during the loading process. The development of inner cracks of recycled concrete in loading process accordingly were the stage of the growing of original cracks, the stage of the expansion of cracks and the stage of the linkage of cracks.
Crack Controlling Research of Concrete Foundation for Large Equipment in Winter
Authors: Qian Da Xing
Published: December 2010

Regarding foundation of large concrete equipment construction in winter as an example, This paper solves a problem that is the conflict between the external thermal insulation in winter and internal commonage in mass concrete cracks controlling. Through the theories according to the specific circumstances of the construction, control objectives and control methods are laid down from various aspects of the construction structure and materials. Foundation of the large concrete equipment cracks is controlled successfully in winter.
Experimental Study of Shear Behavior of High-Strength Concrete Beams with High-Strength Stirrups
Authors: Shi Qing Xuan , Tian Yuan , Hou Wei
Published: December 2010

This paper presents an experimental study of shear behavior of simply supported HSC beams reinforced with high-strength stirrups under monotonic concentrated loading. Six specimens with 150×300 mm square cross section were tested. The effects of three variables such as the stirrup ratio, stirrup yield strength and average confining stress are studied. Based on test results, the shear behavior of HSC beams with high-strength stirrups was evaluated. Combined with other test results, shear strength measured in test are compared with the values calculated according to the expressions proposed in this paper and in Code for design of concrete structures of China (GB 50010-2002). The study concludes that shear capacity is sparingly estimated by the Code for design of concrete structures of China (GB 50010-2002) when the average confining stress below 3MPa, but it is emphasis on insecurity when the average confining stress exceeds 3MPa. The empirical equation proposed in this paper for predicting the shear strength of HSC beams with high-strength stirrups is appropriate.
Investigation of Electromagnetic Interference Shielding Effectiveness of Cement-Based Composites Filled with Carbon Materials
Authors: Xiong Guo Xuan , Zhang Zhi Bin , Deng Min , Zhou Yu Fen
Published: December 2010

The cement-based composite shielding materials filled with carbon materials such as ordinary carbon materials (graphite, coke and carbon black), carbon fiber and nano-carbon materials (carbon nano-tube and nano-carbon black) were prepared. The relationship of conductivity and shielding effectiveness in a frequency range of 100 KHz~1.5 GHz was studied. The electric properties of cement-based composites filled with carbon fiber is better than other carbon materials. With the contents of carbon fiber of 5.vol%, the average shielding effectiveness is about 37 dB and the maximum shielding effectiveness reaches 40 dB.
Behavioral Prediction of Reactive Powder Concrete Based on Artificial Neural Network
Authors: Ji Tao , Zhuang Yi Zhou , Chen Bao Chun , Huang Zhi Bin
Published: December 2010

Based on orthogonal array testing strategy (OATS), the effects of sand-binder ratio (S/B), water-binder ratio (W/B), and the ratio of steel fiber volume to reactive powder concrete (RPC) volume (STF/R) on the compressive strength and chloride diffusion coefficient of RPC were investigated using an artificial neural network method. Research results reveal that the compressive strength of RPC approaches summit when STF/R is 2% or W/B is 0.18-0.2%, and decreases with the increasing of S/B. Furthermore, the chloride diffusion coefficient increases with W/B or STF/R and decreases with S/B.
Experiment and Finite Element Study on the Structural Behavior of Steel Sandwich Panels
Authors: Zha Xiao Xiong , Qin Pei Cheng , Wang Hong Xin
Published: December 2010

This work try to deal with the analysis of a class of sandwich panels widely employed in engineering constructions. In order to study its structure behavior, a systematic experimental study on both roof and wall sandwich panels filled with Polyurethane foam (PU) under uniformly distributed load is conducted. Informed by the tests, appropriate finite element models are developed to model the tests.
Experimental Research on Physical and Mechanical Properties of Steel Fiber High-Strength Concrete
Authors: Wang Yu Dong , Fan Xiao Chun
Published: December 2010

Based on experiment, the mix proportion matching with the design and construction requirements is obtained. It meets with the requirement of pump structure on the basis of meeting the strength requirement. On this basis, the basic physical and mechanical performance is studied and the conclusion is that steel fiber high-strength concrete has excellent resistance to splitting, bending and drying shrinkage. The splitting strength and bending strength of steel fiber high-strength concrete named CF60-2 is respectively 38.7% and 56.8% higher than that of plane concrete named C60. The drying shrinkage rate of CF60-2 is 45.5% lower than that of C60 in three days. The results have an important guiding significance to steel fiber high-strength concrete in theoretical and engineering practice.
Laboratory Experimental Study on Pullout Behavior of Mortar Grouted GFRP Soil Nails
Authors: Liu Zhong Yu , Ma Chong Wu , Zhao Zhuo
Published: December 2010

A large-scale laboratory apparatus has been built to study the pullout behavior of mortar grouted glass fiber reinforced polymer (GFRP) soil nails. The axial strain along the nail length and the displacement of the nail head under different pullout loads are measured, and the ultimate pullout load under the overburden pressure is obtained. Then, the influence of the overburden pressure on the ultimate value of the interface friction force is investigated. The experimental results illustrate that the pullout behavior of mortar grouted GFRP soil nails is similar to that of mortar grouted steel soil nails, and the relation between the displacement and the pullout load can be described with the hyperbolic function. In addition, the dilatancy effect of the soil near the nail during pull out should be taken into account in estimating the pullout resistance of soil nails in dense fills.
Destruction Process Analysis of Laminated Ceramic Composites Based on APDL
Authors: Li Bao Feng , Zheng Jian , Ni Xin Hua , Zhao Lei , Zhong Guo Hui
Published: December 2010

Laminated composites are the effective ways to toughen Al2O3 ceramics at present. The destruction process analysis of laminated ceramic composite is studied in this paper taking the Al2O3/ZrO2 ceramic composite as the example through the APDL programming. The micro model is established in ANSYS. And the failure stresses of each ply of the ceramic can be calculated by micromechanics method. Then the calculated failure stresses are compared to the simulated failure stresses. The micro model can visualize the destruction process of laminated ceramic composite. The failure criteria of composite material can be self-defining in ANSYS by using APDL. Some ideas of ANSYS application on composite material are given in this paper.
Study on Thermal Field of Mass Concrete by Experiment and Numerical Simulation
Authors: Li Xiao Yong , Zhang Zhi Gang
Published: December 2010

An experimental study is conducted to simulate the thermal field in mass concrete. Accurate prediction of the thermal stress by analysis is quite difficult particularly at early ages, due to uncertain age-dependent properties of concrete. A series of tests was conducted in which the temperature was measured for a large number of observation points. The effect of aging and the amount of measuring points on thermal field development that can occur in realistic structures was evaluated. Numerical simulations of the thermal field setup were also performed using the finite element with ANSYS software to verify and extend the experimental interpretation and to determine the maximum temperature value which would occur under construction process. Mass concrete temperature field and stress field for specific projects were measured and analyzed. Numerical simulation of mass concrete temperature field for the actual project is compared with the measured results. The results show that the temperature field of numerical simulation results and measured curves result are of the same trend. And it is feasible that mass concrete temperature field is simulated based on ANSYS.
Impact-Echo Based Nondestructive Evaluation of Grout Condition in Post-Tensioned Bridge Ducts
Authors: Wang Zhi Feng , Zhou Xian Yan
Published: December 2010

The field of Nondestructive Evaluation (NDE) is a very broad, interdisciplinary field that plays a critical role in civil engineering for controlling new structures (quality control) as well as for assessing the internal grout condition of prestressed pipes in post-tensioned concrete structures. Because it allows voids in grouted tendon ducts to be inspected and measured without damaging them, impact-echo based NDE provides an excellent balance between quality control and cost-effectiveness. This paper focuses on the nondestructive evaluation of internal injection quality in post-tensioned bridge ducts, and the developments in civil engineering NDE in China are also introduced.
Gradient of Soil Constitutive Model
Authors: Ma Wen Xu , Fang Ying Guang
Published: December 2010

For the soil is a very complex natural material, significant strain gradient effect exist in soil analysis. Based on the "gradient" phenomenon, we add the plastic strain gradient hardening item into the traditional Cambridge yield surface. By using the consistency conditions and associated flow rule, we get the explicit expression of plastic strain gradient stiffness matrix. And the finite element method of plastic strain gradient is also shown in this article. Plastic strain gradient is actually a phenomenological non-local model containing microstructure information of the material. It may overcome the difficulties in simulating the gradient phenomenon by traditional mechanical model.
Effect of Crumb Rubber Modifier on Pavement Performance of Wearing Course Asphalt Mixture
Authors: Qiu Xin , Chen Lan Yun , Xue Liang
Published: December 2010

The paper investigates the effects of different concentrations of crumb rubber (CR) on the pavement performance of the conventional penetration-grade 80/100 bitumen and the dense-graded wearing course asphalt mixture (AC16). A wet process and 0.6mm size CR were used and the control variables included three types of CR of concentrations 5%,10% and 15% by total weight of binder. The evaluations were twofold. Firstly, a comparison of the basic and rheological properties of those modified and unmodified binders was conducted. Secondly, a comparison of the resistance to moisture damage, low temperature cracking and permanent deformation of the AC16 and CR modified AC16 was performed. The results show that all the CR modified binders and mixtures are found to have improved performance as evaluated by a series of laboratory tests. In addition, among three CR concentrations, AC16 modified with 10%CR by total weight of binder exhibits the most satisfactory performance properties with respect to the resistance to moisture damage, permanent deformation and low temperature cracking.
A New General Solution for the Bending and Vibration of Orthotropic Rectangular Thin Plates with Four Free Edges
Authors: Zhang Hong , Que Hai Qun , Ding Huan
Published: December 2010

This paper firstly introduces a new general solution constructed by double trigonometric cosine series with supplementary terms for the bending and vibration analysis of orthotropic rectangular plates with four free edges on the Winkler foundation subjected to arbitrary vertical force. The general solution, which is fourth-order continuously differentiable with less undetermined coefficients, can be used to solve the bending and vibration problems of orthotropic rectangular plates on the Winkler foundation with various physical parameters requiring no classification and superposition. This makes the bending and vibration analysis of orthotropic rectangular plates with four free edges on the Winkler foundation more unified, simplified and regulated. This paper also gives a Series of analytical example to prove that the method is feasible.
Characterization of Plasma Electrolytic Oxidation Films Formed on AZ31 Magnesium Alloys by Different Voltage Parameters
Authors: Wang Li , Chen Li , Fu Wen
Published: December 2010

Plasma electrolyte oxidation films (PEO) on AZ31 magnesium alloy were prepared in alkaline silicate solutions with two kinds of voltage waveforms (constant voltage waveform and escalating voltage waveform). Discharge characteristics and the dielectric barrier layer formation of the films formed under two voltage waveforms were investigated. Structure, composition, morphology and corrosion resistance characteristics of the films were studied with scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and potentiodynamic corrosion testing. The porosity of the films was calculated with Mat lab software. Structure, composition and porosity of the films are correlated with changes in behaviors of spark discharges on the surface in oxidation process. The escalating voltage waveform strongly affects the transformation of Mg2+ from the substrate but not the SiO32- ions in the electrolyte and the compactness of dielectric barrier layer. The films formed under escalation voltage waveform exhibited lower porosity and higher corrosion resistance than the films formed under constant voltage waveform because of less defects on the surface of the films. The voltage waveform change has little influence on the thickness of the films.
Effect of Epoxy Binder on Fire Protection and Bonding Strength of Intumescent Fire Protective Coatings for Steel
Authors: Yew Ming Chian , Ramli Sulong Nor Hafizah
Published: December 2010

This study focuses on the effect of epoxy emulsion, a binder for producing water-borne intumescent fire protective coating for steel structures. The influence of binder on the fire resistive performance, char formation, thermal stability and bonding strength of the coatings were investigated in detail by using Bunsen burner test, thermogravimetry analysis (TGA), field emission scanning electron microscopy (FESEM) and Instron microtester. It was found that the fire protection performance and foam structure of coating sample D2 was significantly improved by adding 10wt% of epoxy resin which produced the greatest thickness of char layer. In addition, TGA results showed that the residue weight of coating D2 was higher than coating sample D3 with 15wt% of epoxy. This indicated that sample D2 has better anti-oxidation and thermal stability. The results of Instron microtester indicated that the bonding strength of the coatings was improved with the increase of epoxy content.
The Analysis of the Stress Field and Crack of Rock under the Blast Loading
Authors: Zhang Zhong Guo , Bian Ya Dong , Gao Bin
Published: December 2010

The crack tip stress field of rock is analyzed under blast loading, and the crack arrest criterion, the conditions of rock crack initiation and crack extension are presented in this paper. The study will help the design of maintaining the stability of stope drift active workings.
Character of Embankment Reinforced with Geotextile on Sloping Weak Foundation
Authors: Liu Jin Long , Liu Jie Qun
Published: December 2010

Based on nonlinear finite element method, the character of embankment reinforced with geotextile on sloping weak foundation has been studied. It is shown that the lateral displacement of embankment has been distinctly effected by the sloping of foundation, the value of lateral displacement on sloping foundation is greatly bigger than that of horizontal foundation. The peak value of lateral displacement can be effectively reduced by geotextile. With the same condition, geotextile in sloping foundation acts a more important effect than that of horizontal foundation. The development of plastic zone of embankment has been impeded and separated by geotextile, which enhanced the stability of embankment. The results also indicated that, if necessary, reinforcement such as anti-slide pile should be layout at lower toe of embankment on sloping weak foundation.
Theory Analysis for Magnetic Fluid Inclination Sensor
Authors: Sun Ming Li , Cui Hai Rong , Wang Bin , Lu Shuang
Published: December 2010

The paper presents an inclination transducer with magnetic fluid, being dedicated to measure little inclination angles in comparison with a horizontal or a vertical plane. The functioning principle is submitted. The results of theory analysis show that output voltage of sensor and inclination angles are linear dependence. The factors affecting the sensor sensitivity are inspected, which include the exciting signal frequency, the peak voltage and the susceptibility of magnetic fluid.
Flexural and Crack Behaviors of RC Beams Applied with UHTCC Cover Subjected to Rebar Corrosion
Authors: Cai Xin Hua , Xu Shi Lang , He Zhen
Published: December 2010

Ultra high toughness cementitious composite (UHTCC) is a newly developed, high performance, fiber-reinforced cementitious composite with substantial benefit in both high ductility and improved durability due to its tight crack width. The failure pattern of UHTCC exhibits saturated multiple fine cracks, so the durability of structures will be improved markedly by utilizing UHTCC partly or entirely instead of concrete. In this study, a total of 20 beams, including reinforced concrete beams that the cover zone was replaced by UHTCC (the thickness is 15mm, not containing reinforcement, and 50mm, containing reinforcement, respectively), reinforced concrete beams and reinforced UHTCC beams, had been manufactured. A power supply was used to accelerate the corrosion process of reinforcing bars, inducing different degrees of corrosion (the corrosion ratio was 1%, 2%, 4% and 5%) into reinforcing bars. The time of the cracks occurred and the crack width were recorded and the beams having different corrosion ratios of reinforcing bars were then tested under four-point bending for their load-deflection relations. The results showed that UHTCC could restrict the corrosion expansive crack of cover effectively, convert the crack pattern, and delay the appearance of first corrosion expansive crack, thereby to raise the service life of reinforcement concrete structures or components. Meanwhile, the bending test of beams after accelerated corrosion showed that the beams with a cover replaced by 50mm UHTCC and reinforced UHTCC having smaller amount of strength reduction and a reasonable ductile failure after corrosion. The experimental results showed that UHTCC could effectively delay the cover expansive cracking due to corrosion of reinforcing bars retain the ductile properties of reinforced concrete beams after reinforcing bar corroded.
Flexural Capacity of Concrete Beams Prestressed with Carbon Fiber Reinforced Polymer (CFRP) Tendons
Authors: Du Xiu Li , Wang Zuo Hu , Liu Jing Bo
Published: December 2010

Fiber reinforced polymer (FRP), particularly those incorporating carbon fiber (CFRP), has high strength, high stiffness-to-weight ratio and high resistance to corrosion, which shows potential for use as prestressing tendons in corrosive environment. However, concrete beams prestressed with FRP tendons have showed brittle flexural failure due to the elastic rupture of FRP tendons. In order to improve the ductility, a combination of bonded and/or unbonded prestressing tendons was used. Nine prestressed concrete beams were tested up to failure to study the effect of bonded and unbonded FRP tendons on their flexural capacity. Three factors were taken into consideration; the bonding condition of CFRP tendons, the location of CFRP tendons and the prestressing ratio. Also an analytical investigation was carried out to extend some flexural capacity calculation equations to this beam type. The results of the experimental showed that under the same condition, the carrying capacity of concrete beam prestressed with bonded FRP tendons was 20% higher than that of internal unbonded prestressed beam, and was 40% higher than that of external unbonded prestressed beam without deviators. By combination of bonded and unbonded FRP tendons, the ductility of prestressed concrete beams can be improved.
An Experimental Study on Workability of Dry-Mixed Self-Compacting Concrete
Authors: Wang Xiu Shi , Wang Jian Guo , He Pei Xiang
Published: December 2010

This paper addresses mainly workability of dry-mixed self-compacting concrete (DSCC) based on the experimental study. Ten mix proportions for DSCC are designed by the orthogonal test method with fixed fine and additive content when coarse aggregate content and water content are used as variables. The workability (including filling ability, passing ability and segregation resistance) of fresh DSCC is quantitatively evaluated by slump flow, L-box, U-box and circular steel column of stability tests. It is found that DSCC of 13% water content has better fluidity, deformability and filling ability than DSCC of 12% water content and better uniform aggregate distribution and segregation resistance than DSCC of 14% water content based on the experimental results. It can be concluded that DSCC of 13% water content presented in this paper satisfy various requirements for workability and can be used for the design of practical concrete structures.
Experimental Investigation and Analytical Modeling of Eccentrically Loaded Composite Short Columns Confined with Glass Fiber-Reinforced Polymer Tube
Authors: Guan Hong Bo , Wang Qing Xiang , Ruan Bing Feng
Published: December 2010

This paper presents the results of the experimental program and analytical modeling for performance evaluation of the eccentrically loaded composite short columns confined with Glass Fiber-Reinforced Polymer (GFRP) tube. This test matrix included six specimens, which were tested in the variable eccentricity. Research findings indicated that the strength of the concrete-filled GFRP tubular column was enhanced correspondingly; however, the strength gain caused by the GFRP tube decreased as the ratio of e/d0 was increased. A nonlinear analysis that accounts for the change in eccentricity caused by the lateral deformation was proposed to predict the columns’ strength. A comparison between analytical and experimental results of the present study demonstrated the accuracy and validity of the proposed analysis.
Stiffness Revising to Recycled Course Aggregate Reinforced Concrete Beams under Short-Term Loading
Authors: Bai Wen Hui
Published: December 2010

This paper mainly studies the deflection under short-term loading of recycled course aggregate reinforced concrete beam is calculated by using of the formula of short-dated rigidity in code for design of concrete structures. According to testing the flexural performance of 6 recycled course aggregate beams with the same section size, different replacement ratio of recycled coarse aggregate of 0%, 50%, 70%, 100% respectively and different percentage reinforcement of 0.68%, 0.89%, 1.13% respectively, analyzes relation between deflection and replacement ratio of recycled coarse aggregate, deflection and percentage reinforcement, compare measured value and calculated value using of current codes and make statistical analysis this data . By regressing and analyzing the experimental data from literature, supplied short-dated rigidity modified formula of recycled course aggregate beam. The calculation results are in good agreement with the experimental data. The formula of short-dated rigidity can accurately calculate deflection under short-term loading of recycled course aggregate reinforced concrete beam, and can be referenced in engineering practice and correlative regulations.
Study on Properties of Blended Finely Ground Limestone Powder Cement and Compressive Strength of Mortar
Authors: Lv Heng Lin , Jia Fu Ping , Cheng Yong , Li Yong , Long Yu , Yang Jie
Published: December 2010

The effect of replacement of Portland cement by ground limestone as well as its specific surface Blaine (SSB) on the physical-mechanical properties of fresh and hardened cement paste is studied. The binder was composed of cement and limestone, which was prepared by eight replacement levels of limestone powder (0,5,10,15,20,25,30 and 35%) of binder by mass and four levels of SSB (300,600,800 and 1000 m2/kg). Test results demonstrated that the water requirement of normal consistency and the setting times(initial and final) decreased obviously as the replacement level of limestone powder increased and the extent of reduction was noticeable with the increase of SSB of limestone powder. The compressive strength of mortar incorporating different replacement levels and various SSB of limestone powder increased steadily with ages. The compressive strength decreased with the increase of replacement level of limestone, while as increased with the increase of SSB at the same replacement level and ages. The SSB influence factor was created to describe the effect of SSB of limestone powder on the compressive strength. The strength activity index of limestone powder concerning the replacement levels, SSB of limestone powder and mortar ages was established. The grade of limestone powder was suggested in order to reasonable utilization.
Free-Form, High Energy Performance, Transparent Envelope
Authors: Alonso Luis , Lauret Benito , Alonso Fernando
Published: December 2010

This article examines, from the energy viewpoint, a new lightweight, slim, high energy efficient, light-transmitting envelope system, providing for seamless, free-form designs for use in architectural projects. The research was based on envelope components already existing on the market, especially components implemented with granular silica gel insulation, as this is the most effective translucent thermal insulation there is today. The tests run on these materials revealed that there is not one that has all the features required of the new envelope model, although some do have properties that could be exploited to generate this envelope, namely, the vacuum chamber of vacuum insulated panels (VIP), the monolithic aerogel used as insulation in some prototypes, reinforced polyester barriers. By combining these three design components — the high-performance thermal insulation of the vacuum chamber combined with monolithic silica gel insulation, the free-form design potential provided by materials like reinforced polyester and epoxy resins—, we have been able to define and test a new, variable geometry, energy-saving envelope system.
Experimental Study on the Flexural Behavior of Concrete Beam Reinforced With HRBF500 Steel Bars
Authors: Zhang Ji Wen , Ge Wen Jie , Dai Hang , Tu Yong Ming
Published: December 2010

In order to investigate the flexural behavior of concrete beam reinforced with 500MPa fine grain high steel bars, four rectangle cross-section concrete beam subjected to static bending test were made. Mechanics characteristic, flexural capacity of normal section, crack and deflection were analyzed according to current related China code. The results show that the flexural behavior of concrete beam reinforced with 500MPa fine grain high steel bars is similar to normal concrete beam, the average strain of concrete section keep plane; flexural capacity and average crack spacing could still calculated by current code for their values coincide well with tested value; however, deflection values of the specimens calculated by current related China code are smaller than corresponding tested value; under the state of serviceability, crack width and deflection of the specimens were found not to meet the requirement of current China code while the design value of yield strength of 500MPa fine grain steel bar was taken more than 360MPa.
Experimental Investigation on the Damage Localization of Limestone under Triaxial Compression Condition
Authors: Yang Hai Qing , Zhou Xiao Ping
Published: December 2010

The phenomena of Damage localization, which characterized as the rock mass suddenly enter into the deformation localization stage after a period of uniform deformation, is the beginning of rock failure. Damage localization is also the precursor of rock failure. Utilizing the image enhancement and segmentation technology, the rule of damage evolution of limestone under triaxial compression is analyzed. Moreover, The computerized tomography images are analyzed by the method of digital image processing, which includes threshold partition and edge detection, and then the relationship between computerized tomography image and damage evolution is discussed. Meanwhile, the dependence of fractal dimensions of rock section on the axial stress is determined by the method of box-counting dimension. It is concluded that the fractal dimension may reach a minimum value at the point of damage localization, and after that damage become more severe.
Numerical Simulation of Traffic Emissions in Urban Street Canyon
Authors: Wang Peng , Zhao Dai Qing , Cai Guo Tian , Liao Cui Ping
Published: December 2010

Dispersion of gaseous pollutant emissions in different street canyons was studied using two dimensional sections of canyon models airflow. Effects of building size, street width wind velocity and different turbulent model on the pollutant transport were examined. Depending on wind speed, building height, and street width, it was found that large recirculation regions in canyons may form. Under certain conditions, gaseous pollutants emitted from vehicle exhaust may trap inside the street canyon. It was shown that the amount of pollutants in street canyons reduces when the wind speed increases. The simulation results were compared with the available wind tunnel experiments and favorable agreement was found.
The Analysis on Coefficient of Horizontal Subgrade Reaction of the Guardrail in the Highway
Authors: Yang Lu , Chen Dai Heng , Zheng Hong
Published: December 2010

For exactly analyzing the course of the coupling impact of auto and protective guard pillar, it’s especially important to get the analytical solution of the coefficient of horizontal subgrade reaction of the horizontal column of protective guard pillar. Using the reaction relationship of soil density and horizontal load ,we build up the estimate theory of the coefficient of horizontal subgrade reaction, with a simple form, describing the relationship of horizontal subgrade reaction and horizontal displacement. Using the Mohr-coulomb yield criterion and the finite element numerical simulation result of ABAQUS, we found that during the column rotary deformation, the coefficient of horizontal subgrade reaction is not a constant ,but it will be smaller and smaller with the development of the deformation. Plastic yield of protective guard pillar and earth coupling model soil caused by horizontal load depends on the difference in value of the max stress component and the min stress component, at the same time raising a theoretical formula of the coefficient of horizontal subgrade reaction and ultimate bearing capacity of soil and setting the theoretical model of coefficient of horizontal subgrade reaction under the horizontal load ,to provide a reference of design and analyze for the practical project.
Flexural Vibration in a Binary Phononic Crystal Thick Plate with a Point Defect
Authors: Yao Zong Jian , Yu Gui Lan , Wang Yue Sheng , Li Jian Bao
Published: December 2010

Based on the finite element method, the propagation of flexural vibration in a binary phononic crystal thick plate with a point defect is studied. The plate is composed of a square array of concrete cylinders embedded in the rubber matrix. Complete band structure and frequency response function of this perfect thick plate indicates the existence of low-frequency absolute band gap. Detailed investigations have been carried out to study the dependence of the width of absolute band gap on both structural and material parameters. For the point defect, the defect modes are localized around the defect, and the frequency and the number of the defect bands are significantly dependent on the filling fraction, the size and the mass density of the defect cylinder. To better support the statement of the defect band structures, we also represent the frequency response function of the propagation of flexural vibration in the thick plate with a point defect. Based on the detailed investigations, both the absolute band gap and the defect bands of a binary thick plate could be modulated with appropriate parameters. It may be useful to vibration control in engineering structure.
Effects of Low-Angle Grain Boundaries on the Yield-Strength Ratio of High Grade Pipeline Steels
Authors: Xu Dong Ying , Yu Hao
Published: December 2010

Orientations distribution between grains of two high grade pipeline steels were investigated by electron back-scattered diffraction (EBSD). Then the percentage of low-angle grain boundaries was studied qualitatively to analyze the effect of low-angle grain boundaries on the yield-strength ratio of high grade pipeline steels. From the mode of coordinate deformation and the ability to resist deformation by the grain boundaries, the results show that when the effective grain size are almost the same, the pipeline steel which has the smaller percentage of low-angle grain boundaries, the larger difference between the yield strength and tensile strength, which makes the yield-strength ratio of pipeline steel lower.
Experimental Research on the Anti-Crack Performance and Microscopic Mechanism of the Hybrid Fiber Concrete
Authors: Liu Xiao Fan , Sheng Xiao Zhou , Li Ji Xiang , Lun Yun Xia
Published: December 2010

In order to study the effect of fibers to the anti-crack performance of the concrete, sixteen different plat restraint specimens with four different fiber mixing amount (steel fiber is 0, 0.5%, 1%, 1.5%, and polypropylene fiber is 0, 0.1%, 0.2%, 0.3% respectively), are selected to comparison about the influence on the anti-cracking property of the hybrid fiber concrete, single fiber reinforced concrete and plain concrete. Experiments show that fibers increasing the anti-crack performance of the concrete significantly. The relationship between fibers’ content and the crack area is analyzed, and the microscopic mechanism of the anti-crack performance is discussed. Considering the economy and the convenient for construction, the column ratio of 0.5% steel fiber and 0.1% polypropylene fiber is recommended.
Application of Concrete Bar-Type Plank in Constructional Engineering - a Case Study of State Key Laboratory for Green Building Materials
Authors: Cao Ying , Yang Jin Peng
Published: December 2010

This paper introduces performances and characteristics of concrete bar-type plank, a new type of building materials, through detailed graphics recording its applications in State Key Laboratory for Green Building Materials. Also, it proposes issues in further research and potential direction for concrete bar-type plank development widespread used in actual projects, i.e., to become an exterior wall structure system rather than a simple decorative component.
Preparation of Foam Glass Composite from Iron Ore Tailing
Authors: Zhang Shu Hui , Kang Zhi Qiang , Lu Qing
Published: December 2010

Foam glass composite with good capabilities was prepared from iron ore tailings as the main material by two steps. The phase composition and microstructure were determined by X-ray diffraction and scanning electron microscopy. The effects of foaming temperature and sintering temperature on sample capabilities were studied by determining sample bulk density and compression strength. The results show that the main phase of basis glass powder is amorphous mineral. The foam glass composite with enclosed circle pore mainly concludes Ca[(Fe,Mg)][SiO3]2 and amorphous glass. The diameter size of pore is wide and distributes evenly. The foam glass composite, whose compression strength is 62.25MPa, and bulk density is 2.056 g/cm3, has fine complex capabilities. With the increase of foaming temperature the sample pore diameter size raises, while bulk density and compression strength reduces. The bulk density and compression strength all diminish firstly and raise subsequently with the sintering temperature increasing. The optima temperature parameters are foaming temperature of 900~950 and sinter temperature of 1100 .
Micro-Mechanics of UPR Composite Toughened by Rigid Nano-Particles
Authors: Peng Ying , Liu Jian Hua , Hu Xun Pu
Published: December 2010

The toughening for UPR composite effect of rigid nano-particles was studied. By the tensile test, it was confirmed that with the increase of the organic rigid particle PA6 and inorganic rigid nano-particles SiO2，toughening effect for the UPR was better. The Generalized Method Cell of the micro-mechanical constitutive of the rigid particles and UPR phase was established. The macro- plastic deformation was simulated by the correlation of parameters for micro-mechanical and macroscopic mechanical, the simulation curves were well fit with its experimental curves。The numerical results indicate that the nonlinear theoretical method can simulate the plastic strain curves of composite well.
The Preparation and Research of Thermal Energy Storage Concrete
Authors: Wang Chao Hui , Gu Xiao Hua , Liu Jian Hong , Ba Xue Wei
Published: December 2010

In this paper two different thermal storage material were respectively covered by polymer layer, inorganic layer and simple way to join the concrete. Thermal energy storage and mechanical performance were researched, the reliable use methods of the thermal energy storage in the actual engineer were proposed.
Natural Vibration Characteristics of Long-Span Suspension Bridge with CFRP Cables
Authors: Zheng Hong Yu , Jiang Huai Yan , Lu Zhi Tao
Published: December 2010

A non-corrosion, high strength, light weight material – carbon fiber reinforced polymer (CFRP) is introduced to replace steel as cable system in long-span suspension bridge for improving loading efficiency, reducing maintenance cost, enlarging the span of suspension bridge. The natural vibration characteristics of such new suspension bridge with CFRP cables are investigated by means of finite element in this paper. Two 2000m-span suspension bridges with steel cables and CFRP cables respectively are designed, analyzed, verified and compared. The analysis results provide a picture of the changes in natural vibration characteristics and the wind stability and earthquake-resistant behavior are briefly discussed if CFRP cables were applied.