bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiscale Modelling of Progressive Damage in Fiber-Reinforced Composites
Authors: Wang Fang , Chen Zhi Qian , Meng Qing Fang
Published: May 2011

A multiscale approach based upon micromechanical fiber/matrix/interface scale in fiber-reinforced composites was established to simulate the progressive damage at macroscopic scales. The composite is reinforced with Boron fibers under conditions of matrix tensile yield and interface debonding. An analytical solution using a superimposition technique within the framework of shear-lag model was employed to derive stress profiles for any configuration of breaks under applied loading. A simulation scheme coupled with Monte-Carlo method was proposed to investigate evolution of damage-plasticity of the composites.
Application of Thermoelectric Generation Technology in Building-Integrated Photovoltaics (BIPV)
Authors: Wei Chen Guang , Liu Zheng Quan , Deng Xiao Ying
Published: May 2011

In recent years, Building Integrated Photovoltaic (BIPV) system has been becoming one of most important application of solar energy. Heat is the key of the BIPV design. If the temperature of photovoltaic modules is too high, it will affect the efficiency of solar cells, the structure performance of the components and service life. This paper present a photoelectric-thermoelectric (PV-TV) model which can collect heat from the solar panels so that to reduce its surface temperature, and then to generate electricity by using of temperature difference technology and devices. The model presented in this paper provides designers a new concept in BIPV design.
Density Influence on Matric Suction of the Eolian Sand under the Condition of Loop of Dehumidifying and Humidifying Process
Authors: Song Yan Xun , Xu Qiang , Li Xi An , Lin Hong Zhou
Published: May 2011

The matric suction has very important influence on the characteristics of unsaturated sand; and it is closely relevant to density. In order to discuss the relationship among the matric suction, water content and dry density, the matric suction of the eolian sand were measured in laboratory. The soil-water characteristics curves for unsaturated eolian sand with different dry densities are obtained. The test results show that the variation tendency of soil-water characteristics curves has been corresponding to the different densities.
Ecological Highway Slope Stability Analysis by Inversion Method
Authors: Gao Jun Zhao , Xiao Guo Feng , Miao Hai Qiang
Published: May 2011

Side slop losing stability is one of the main factors which greatly influences freeway expedite construction, especially after side slop losing stability the determination of rock and soil mechanics parameter may take a long time. Inversion method to analyze slope stability can preferably solve the problem. During the treatment of the ecological freeway landslide, we can not obtain important Parameters due to great disparity of sample Parameters of landslide. However, using inversion method to get cohesion and internal friction Angle, and anglicizing its sensitivity during calculation of stability can identify reliable Parameters. According to slope stability calculus, the ecological reinforcement design scheme come into effect.
Direct Displacement Based Seismic Design of High Rise Structures with Strengthened Stories (I) - Theory
Authors: Yang Ke Jia , Liang Xing Wen , Sun Lin Zhu
Published: May 2011

High rise structures with strengthened stories are widely used nowadays. A rational seismic design procedure for this kind of structure is thus necessary. Based on mode theory and direct displacement based seismic design of multi-story buildings, this paper proposed a new direct displacement based seismic design procedure. In the proposed method, each mode of the high rise structure is equivalent to a single degree of freedom (SDOF) system. Seismic response of each mode is calculated and adds up to consider the contributions of higher modes. Considering the characteristic of strengthened stories, two stories above the strengthened stories are taken as the “key stories”, whose performance indicates the performance of the building. The proposed procedure is logical, simple and can serve for reference of actual design.
The Study of Convertibility of Water Cement Ratio in Recycled Water Permeable Concrete
Authors: Li Ying , Yang Jian Rong , Guo Ting Ting
Published: May 2011

Take the aggregate as subject, based on the water cement ratio, the compression strength of recycled water permeable concrete and evolution of water permeability with a water cement ratio from 0.30-0.43 was researched. And then optimal proportion of recycled water permeable concrete when the compression strength within 10-15MPa and 15-20MPa, and provide a basis for application of recycled water permeable concrete in urban ecological construction.
Direct Displacement Based Seismic Design of High Rise Structures with Strengthened Stories (II) - Application
Authors: Yang Ke Jia , Sun Lin Zhu , Chen Lian Meng
Published: May 2011

Based on mechanical characteristics of high rise structures with strengthened stories, the author performed direct displacement based seismic design on a high rise structure with 2 strengthened stories according to the direct displacement based seismic design principle. The performance levels are set to be “serviceability” under medium earthquake and “life safety” under major earthquake, respectively. The design procedures are with the following features: (1) Definition and selection of “key” stories are based on mechanical characteristics of high rise structures with strengthened stories; (2) Determination of mode number and calculation of horizontal earthquake action verified the availability of the design procedure; (3) some new ideas are proposed to improve the earthquake action calculation and structural performance control. The design procedure verified the effectiveness, feasibility and availability of the proposed direct displacement based seismic design method.
Accelerate Thaumasite Formation in Cement-Limestone Powder Paste by Internal Adding Method
Authors: Li Chang Cheng , Yao Yan , Wang Ling
Published: May 2011

Cement-limestone powder pastes added with 10% magnesium sulfate, sodium sulfate, and calcium sulfate respectively were stored in water at (5±2) °C to accelerate thaumasite formation. The pastes were inspected visually at intervals. And the formation of thaumasite was identified and confirmed by X-ray diffraction (XRD), infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR). The results show that internal adding sulfate in cement-limestone powder paste is an efficient way to accelerate thaumasite formation, and the accelerated effect is magnesium sulfate> sodium sulfate> calcium sulfate. Cement-limestone paste containing 10% magnesium sulfate totally turns into grey-white mushy materials after 6 months immersion, and products are mainly thaumasite and gypsum. In addition, the amount of thaumasite increases along with time of internal sulfate attack in 15 months. XRD, IR, and NMR are powerful and reliable tools for identification of thaumasite in cement-based materials.
Fatigue Investigation of High-Strength Concrete Members Reinforced with CFRP
Authors: Hai Hong , Sun Li , Zhao Ying Hua
Published: May 2011

Fatigue damage becomes an emerging problem in lots of concrete structures which will subject to cyclic loadings during their working life. This paper presents a study on interfacial shear fatigue performance of a high-strength concrete structure strengthened by carbon fiber-reinforced plastic (CFRP) plate, which has been established as an effective method for rehabilitation and strengthening of concrete structures. Based on the static test, a new experimental investigation of the shear fatigue performance along the concrete-plate interface under the low cycle fatigue load in the condition of R=0.1 is presented. The main variable is the concrete strength. Compared with the static ultimate strength, fatigue strength decreases. Therefore, a safety factor of the fatigue strength at the interface of CFRP and concrete should be applied in design.
Comparative Analysis on Seismic Response of Tall Building on Soft and Rigid Foundation
Authors: Ni Xiao Yan , Zhang Yu , Zhang Shi Bo , Huang Wei
Published: May 2011

A numerical calculation model of the dynamic response of a tall building -base- foundation system was built. In the modeling, the beams, columns and stakes was described by the BEAM188, and the floor slab described by the SHELL63. The natural frequency and mode of the vibration of the system were calculated by using ANSYS and the response of the system under both horizontal and vertical seismic action were calculated by using the module, Time-History Seismic Analysis, with the elastic modulus of foundation being set as 20MPa, 20GPa, and 30GPa respectively. The result shows that, the horizontal displacement amplitudes of the system were 0.198m, 0.095m and 0.095m respectively under horizontal seismic action, and were 1.13×10-5m, 1.4×10-11m and 1.4×10-11m respectively under vertical seismic action. So the structures on soft foundation take on stronger capacity of resisting vertical earthquake than that on rigid foundation, and the opposite is the case of resisting horizontal earthquake. The story drifts are respectively 6.2×10-12m, 2.34×10-6m and 3.46×10-6m under horizontal seismic action, and respectively 4.3×10-12m, 4.85×10-6m and 4.78×10-6m under vertical seismic action. The story drifts on soft foundation under both horizontal and vertical earthquake action are much less than that on rigid foundation.
Vertical Dynamic Impedance of Fracture Pile
Authors: Yan Bin , Sun Li Tong , Xu Yao
Published: May 2011

Some damages of piles can be unavoidably caused by natural disasters and extreme constructions. Usually, piles can be cut into two parts by shocks such as earthquakes, that is fracture piles. Obviously, the dynamic behavior of a single fracture pile is different from that of normal piles. But the problems of inspection, appraisal, repairs and maintenance of piles will face us. By studying dynamic behavior of a single fracture pile of vertical oscillation, the paper introduces a dynamic model of the fracture pile. The model is not perhaps perfect, but it is a method to begin to study the vibration of the fracture pile. The individual example does not detail the dynamic characteristics of the fracture pile, but the tendency of the curve of the dynamic impedance versus frequency can give a mainly rule.
Analysis of Collapsed Chimney of Balco Power Plant in India
Authors: Zhang Yu Feng , Li Chao
Published: May 2011

A large under-construction chimney at BALCO Power Plant in central India collapsed on Sep. 23, 2009 under severe stormy weather, causing serious casualties and massive economic losses, while another, similarly built, survived. So far, there has been no strict and scientific analysis on the cause of the accident. In this paper, finite element method is used to simulate the effect of wind loads and the whole collapse procedure based on the investigation of information about the design, the construction, the site related records, etc. The results show that the initial part of the chimney destroyed is the top of the structure (specifically the construction platform and the partial top cylinder wall of the chimney); then the debris from the top fells and crashes the lower part of the structure, eventually leading to the whole structure collapsing. The analysis results are basically consistent with the observation of the debris and the toppling scene and what the witnesses described, and scientifically clarify the actual cause of the chimney collapse. In addition, by comparing the chimney design codes between the USA and China, along with the analysis results, some suggestions are proposed to prevent similar accidents in chimney projects.
The Experimental Research and Theoretical Analysis of Unbonded Prestressed Concrete Flat Beams at High Temperature
Authors: Wang Zhong Qiang , Yu Zhi Wu
Published: May 2011

The experiments of 26 unbonded prestressed concrete flat beams under fire with elevating the temperature according to the ISO time-temperature standard curve were accomplished in the large structures electrical heating furnace that was manufactured independently. The macroscopical phenomena of water penetration, the lube flowing, the spalling of concrete and the corlor change of aspect were observed. The laws of behaviors such as temperature distribution on section,the deformation characteristic and stress varieties of prestressed tendons were investigated through the tests. The experiments indicated that temperature distribution was not uniform, the dynamic continuous deformation and the complicated varieties of prestressed stress occurred at high temperature. Based on the increment temperature-stress coupling constitutive models and chief deformation compatibility of the unboded prestressed tendons, the nonlinear finite element calculation formula took the unknown nodes displacements and the tensile forces in the unbonded tendons as unsolved column matrix simultaneously. The Increment format of nonlinear finite element method and calculation model for whole process analysis of unbonded prestressed concrete flexural members at high temperature were presented. The solution of nonlinear equilibrium equations for unboded prestressed concrete flexural members at high tempure was proposed, and a FORTRAN program named NAUPCLF was developed also and the results were in good agreement. The conclusions can supply the way and basis for further fire-resistant design and analysis of prestressed concrete structures.
Improving Steel Beam-Column Connection with Enlarged Weld Access Hole
Authors: Li Jun , Yu Zheng , Yu You Sheng , Li Ran
Published: May 2011

In this paper, the different sizes of enlarged weld access hole (EWAH) in steel beam-column connection are presented. Based on the commercial nonlinear finite element code ABAQUS, firstly, the sequential welding process is simulated, and the non-linear pseudo-static is performed. Through the comparison of results between the FEA and finished pseudo-static experiment when EWAH size is adopted by x=115mm and y=35mm, it is demonstrated that this analysis method is rational and effective, moreover, the stress concentration effects and cracks are discovered. And then the FEA method still obtains, the EWAH size y=35mm is changeless, the nine structural models are made up for only considering the value range from x=70mm to x=110mm. Furthermore, the impacts of the EWAH size on mechanical behaviour are discussed, and the reasonable geometric range is proposed.
Experimental Study on Flexural Behavior of Damaged RC Beams Strengthened with Prestressed CFRP Plate
Authors: Zhou Rui , Zhang Mei Zhen , Zong Zhou Hong
Published: May 2011

Strengthening using prestressed CFRP plate is a new developed technology in recent years, which can significantly improve the flexural behavior of reinforced concrete (RC) beams. In this paper, an experimental study including four RC beams stengthened with CFRP plates using self-developed anchorage system was carried out. The nonlinear finite element models of the strengthened beams were constructed to simulate the influence of flexural behavior on RC beams strengthened with CFRP plates under different damage degrees. The experimental results indicated that initial damage degrees have greatly influence on the crack distribution and ductility, deflection and the ultimate flexural strength of the strengthened beams, as well as steel reinforcement strain and CFRP plate strain. Meanwhile, the finite element model can predict accurately performances of strengthened RC beams before CFRP debonding. In addition, the numerical analysis indicated that the sustained loading while strengthening RC beam using prestressed CFRP plates would induce adverse effect, so the live loading should be removed before starting the strengthening works.
Prediction of Vertical Ultimate Bearing Capacity in Piles Based on the Improved Hyperbolic Model
Authors: Wang Cheng , Zhang Qi
Published: May 2011

Vertical static load test is widely used in the determination of pile bearing capacity, the mathematical model used to fit test pile data in determining the bearing capacity is essential. From the perspective of analytic geometry, the paper analyzes the traditional method of hyperbola, of which the asymptotic line of equilateral hyperbola was used to determine the ultimate bearing capacity. By extending the equal-axed conditions, a more general form of hyperbolic equation is derived and feasibility of such method is also analyzed, which indicates that the maximum point of curvature in such hyperbolic curve can determine the ultimate bearing capacity and such method is proved to be reasonable in practical projects.
A Nonlinear Force Method Model for Dynamic Analysis of Cable Trusses
Authors: Ma Xing
Published: May 2011

A nonlinear force method model is proposed to study the dynamic behavior of cable trusses. In the paper, travelling wave method is employed to solve the governing equation of motion. After support reaction forces are considered as excitations, cable trusses are extended to infinitude, and D’Alembert solution to the partial differential equation (PDE) is achieved. Substituting the solution into compatibility condition and boundary conditions, the governing equation expressed by dynamic tension is derived, which is named force method dynamic equation (FMDE). Hence the dynamic system of infinite-degree-of-freedom is simplified as a system with only one unknown without any loss of precision. Nonlinear governing equations are developed through considering the effect of quadratic terms of displacements. At last, an example is given to verify the force method model presented in the paper.
Response Modification Factor for Y-Eccentric-Braced Steel Frame Structures
Authors: Yang Wen Xia , Gu Qiang , Song Zhen Sen
Published: May 2011

In current seismic design procedure, structural base shear is calculated according to the linear elastic response spectra divided by response modification factorR. The response modification factor is important to the reliability and economy of building seismic design. In this paper, the response modification factors of Twelve Y-eccentric braced steel frames with various stories and spans lengths were evaluated by capacity spectrum method based on the global capacity envelops obtained from an improved pushover analysis and incremental dynamic analysis. According to the results, an appropriate formula of the response modification factor for the Y-eccentric braced steel frames was suggested.
Finite-Infinite Element Dynamic Analysis of Pile-Soil-Structure System Considering the Change of Groundwater Level
Authors: Hu Wei , Li Guang Fan , Du Juan
Published: May 2011

The rise of groundwater level can reduce soil’s effective stress and destroy it’s structure. As a result, the dynamic characteristics of pile-soil-structure system will be changed remarkably. In this paper, a structural dynamic model was used for saturated loess, and the finite-infinite element model of pile-soil-structure system was established to study the groundwater level’s influence on the system’s dynamic characteristics, which included the distributions of pile section’s shearing stress, horizontal displacement and acceleration. The results indicated that, the height of groundwater level did not change the distribution shapes of shearing stress, horizontal acceleration, but had effect on their values. To the top section’s shearing stress and horizontal displacement, there almost had a same dividing groundwater level. When groundwater level was higher than that one, the shearing stress and horizontal displacement were increasing with the rising of groundwater level, but the regulations were just opposite when groundwater level under that height. The study also shown that, to a determinate geological condition and pile foundation, there has a dividing groundwater level, and which is also the most secure level to the pile-soil-structure system. The conclusion can give theoretic instruction for the safety evaluation of pile-soil-structure system around water area.
Preparation and Basic Performance of Anti-Seepage Slurry for Domestic Waste Landfill Site
Authors: Dai Guo Zhong , Shi Gui Cai , Wu Xiao Feng , Wang Yan
Published: May 2011

One kind of slurry with low permeability coefficient and certain adsorption and retardation to pollutants in leachat is developed in anti-seepage engineering of leachate for domestic waste landfill site. Through the orthogonal experiment, the selected optimal formula of the slurry with a bentonite base is: bentonite 20%~30%; cement 15%~25%; fly ash 20%~25%; Na2CO31.0%~1.4%; diluent FCLS 0.35%~0.75%; and etcaeteras is water. Concretion stone ratio of this slurry is greater than 99.6%; concretion body 28 day permeability coefficient is less than 0.8×10-7cm/s, unconfined compressive strength is less than 2.0MPa; elastic modulus is 50～800MPa. The slurry concretion body’s hindered COD, BOD, NH4-N and phosphorus adsorption rates reach upper 82%, block rate reaches upper 99% to Hg, Pb and other heavy metal ions. The slurry concretion body’s permeability coefficient is low, and its adsorbed or blocked function to landfill site leachate is very well. Meanwhile, it has considered reducing the compressive strength and brittleness of the concretion body, enabling it to have certain plasticity and toughness adapted for the distortion of the base for domestic waste landfill site.
Simulation Experimental Research for the Influence of Embedded Ratio on SMW’s Working Traits
Authors: Chen Wen Zhao , Gao Quan Chen , Jiang Jun She
Published: May 2011

Through model test, the displacement of the top of the wall and the strain of the core pile with excavating were measured and the deformation and damage characteristics of the soft soil foundation pit supported bySMWwas revealed. By parameter sensitivity analysis and back analysis,ABAQUSwas applied to build the numerical simulation model ofSMWin soft soil and the model parameters were obtained and the model was optimized. The impact of the embedded depth on the displacement of the top of the wall ,strain of the core pile, the bending moment of the core pile and the surface subside were systematic studied. The curve fitting equations of the above mentioned action effect variables with embedded ratio were obtained. Studies have shown that embedded depth was significantly influenced the working properties ofSMW. When the embedded ratio reaches a critical value, the nonlinear variation characteristics of the above mentioned action effect variables will occur and the signs of foundation pit's failure will occur.
Study on the Measuring Instruments and Strength Size Effect of the Surface Shape of Rigid Structure Plane
Authors: Ji Feng , Shi Yu Chuan
Published: May 2011

The surface shape of structure plane is closely related with its mechanics property. Precise measurement to the surface shape of structure plane is the basis of deformation mechanism and strength characteristics. On the basis of studying advantages and disadvantages of the measuring instrument, the author has developed a new kind of portable measuring instruments innovatively - Contact Punching Device which has improved open-air working efficiency greatly. Application results show that JRC obtained by the Contact Punching Device is very close to the actual JRC of surface shape of the structure plane. Then about size effect of rigid structure plane, got the following principle that the statistical variance of the undulating roughness of the structure surface decays gradually with length of the rock sample, and got the limiting length of the undulating roughness when the influence of shearing intensity of the structure is dispelled. Finally, which proved through the embodiment of different rock and different weathering rock, the result indicates this method can be applied to engineering.
Prestressed Concrete Covering Layer System Depth Zonation in Marine Environment
Authors: Chen Feng , Sun Yi Li , Hu Da Lin
Published: May 2011

The chloride ingress of prestressed concrete should consider much more factors than common reinforced concrete. And the prestressed concrete covering layer system is a complex system which includes not only the non-uniform layer of concrete, but also the non-prestressed reinforcement, the metal corrugated pipe and the cement paste incrustation body in the pipe. Taking into consideration of the effect of stress level in concrete and the non-prestressed reinforcement, the multi-factors for chloride ingress corrosion model is achieved and the durability limit state equation for prestressed concrete structures is established. The paper presents a determination method for the depth of the covering layer system of prestressed concrete structure in marine environment. The principle for zonation of the prestressed concrete covering layer system’s minimum depth is established after sensitivity analysis of the effect factors in the marine environment, and the environment temperature and humidity are identified as the main environment sensitivity factors for the depth. Therefore, the paper also proposes zoning method and the division regions for the prestressed concrete covering layer system depth of the coastal region in China.
Study on Interaction between Soil and U-Shaped Subway Tunnel in the Environment of Ground Fissures
Authors: Liu Yang , Li Kai Ling , Men Yu Ming , Weng Guang Yuan , Liu Hong Jia
Published: May 2011

The interaction mechanism, between soil and U-shaped Subway tunnel, is studied by numerical simulation in the environment of ground fissures. The Subway Line 2 through the ground fissures in Xi’an. The analysis results show that the soil mass influenced by the relative displacement and the vertical displacement gradually increases with the relative displacement increasing of ground fissures movement. The deformation area of tunnel lies in the two sides of presupposed ground fissure, and the area enlarge with vertical relative displacement increasing. The tunnel structure damages at the ground fissures when the relative displacement reaches to 100mm. The footwall part is in tension and the hanging wall part is under pressure on the top of tunnel structure at the ground fissure. The footwall part is under pressure and the hanging wall part is in tension on the bottom of tunnel structure at the ground fissure. In the practical projects, the sectional type tunnel should be employed when the Subway tunnel through the ground fissures.
The Structure Design of Steel Structure Resident Building
Authors: Yang Hong Mei
Published: May 2011

With China's steel structure housing industry vigorously develop, the steel structure housing has been widely used in our country. In this paper, the steel structure housing structure and design essentials are introduced. Among design essentials, steel, the choice of connecting materials and wall materials, node design, the waterproof design of toilet and kitchen, floor systems design, the corrosion of steel structure, steel welding design and so on are mainly introduced.
Rolling Stones under the Action of the Numerical Simulation Research Shed Hole
Authors: Yang Lu , Li Shi Min , Chen Dai Heng , Wu Zhi Min
Published: May 2011

With a rolling stone gathers tent hole structure as the prototype, using ABAQUS finite element software to simulate the rolling stones impact process with different impact, research rolling angle and speed impact tent hole structural dynamic mechanical response for rolling stone protection design, provide necessary basis. The results show that the rolling stones in different speed and incident angle of tents hole shocks on concrete protective structure of contact force ,displacement and injuries have great influence and for the rolling stones protection engineering design to provide theoretical reference.
Experimental Study on Shear Capacity of Broad-Limb Special-Shaped Columns
Authors: Wang Tie Cheng , Chen Xiang Shang
Published: May 2011

The experimental study on shear capacity of 24 broad-limb special-shaped columns subjected to low cyclic loading were executed. The characteristic of hysteretic curve and skeleton curve were analyzed. The influences of the lateral bevel loads and the limb’s width-thickness ratio on the shear strength of the T-shaped and L-shaped broad-limb special-shaped columns were studied. The application of the shear formula in the current code for the broad-limb special-shaped columns was verified. It is shown that using the formula to calculate the shear strength of broad-limb special-shaped columns is safe from the results.
A Study of Beijing’s Suburban Residential Areas
Authors: Li Xu Jia
Published: May 2011

This paper is an analytical study of the planning techniques of the new residential areas in Beijing’s suburbs at the turn of the 21st century, including the scale, structure, road network, green system and public building arrangements of a housing program. Its purpose is to reexamine the assumptions for the planning techniques of modern residential areas, recheck the legitimacy of these techniques, and reconsider residential areas as a proper residential model for modern Beijing. The paper evaluates three issues related to the modern residential areas: the controversies associated with super residential areas, the relationship between pedestrians and automobiles, and urbanization and mix-use communities.
Study on Finite Element Model of Infilled Walls of Steel Frames
Authors: Zhao Xin , Wu Mai , Kong Dan Dan , Chen Shun Wei
Published: May 2011

Autoclaved lightweight concrete (ALC) block infills are used widely for steel residential building system in China; the authors of this paper brought forward a kind of macro finite element (FE) model of ALC block infills of steel frames on the basis of experimental study. Furthermore the hysteresis model of the strut element of infill was established. At last the validity of the strut element was verified by comparison theory analysis results with experiment ones. The analysis method and theory of this paper can be applied to other kind of infills after being revised properly.
Durability Research on Masonry Structures of Historical Buildings in Xi’an Beilin Museum
Authors: Dong Zhen Ping , Hou Cong Xia , Liu Xi Guang , Wang Qing Lin
Published: May 2011

By the Xi'an Beilin Museum of Historic Buildings Survey durability of brick masonry and brick surface material X-ray diffraction analysis showed that the durability of historic buildings degradation of common brick, Environmental conditions and construction materials with different degree of degradation is a clear significant difference. According to the survey results, analysis of the durability of brick masonry deterioration of historic buildings causes and influencing factors, such as the future durability of brick masonry buildings to provide a reliable basis for restoration.
Experimental Study on Development Characteristics of Dynamic Pore-Water Pressure of Anti-Filter Material in High Earth-Rock Dam
Authors: Meng Fan Li , Pan Li Shuang , Lu Cheng Yuan
Published: May 2011

A series of dynamic triaxial tests which used saturated samples of three different particle size distribution anti-filter materials in high earth-rock dams have been investigated for the development of dynamic pore-water pressure. The experimental results show that the relationship between μd/σ'm and N/Nf in the same consolidation condition are unitary if we applied different dynamic stress to the same particle size distribution anti-filter material. Besides, if N/Nf <0.6, the value of μd/σ'm increases quickly. The increase rate of μd/σ'm will be slower if N/Nf≥0.6. When the consolidation stress ratio is invariant, the change of ambient pressure has no effect on relationship between μd/σ'm and N/Nf. When the gradation and ambient pressure of anti-filter material are changeless, the change of consolidation stress ratio has obvious effects on relationship between μd/σ'm and N/Nf. When the value of consolidation stress ratio is increase, the number of dynamic pore-water pressure ratio obviously decrease. When the consolidation condition of anti-filter material is changeless, the change of anti-filter material’s grade doesn’t have obvious effects on the relationship between μd/σ'm and N/Nf.
Research on Incentive Equilibrium Mechanism of Agent-Construction Relationship Based on Multitask Principal-Agent Model
Authors: Wu Zhong Bing , Yao Bing , Liu Yi Sheng , Jiang Shi Jie
Published: May 2011

Most of the Chinese scholars have simplified the relationship between the client and the agent-construction enterprise as a single-task principal-agent problem, which has ignored the important fact of multitasks, such as progress, quality and cost. In this paper, a multi-task principal-agent model with three tasks, i.e. progress, quality and cost, is constructed to analyze the optimal incentive contractual conditions and multi-task incentive equilibrium mechanism of the agent-construction enterprise, which can provide theoretical basis for the regulatory policy of government investment project.
LQG Modal Control on Spatial Structures Using MR Damper
Authors: Lin Wei , Chen Shang Hong , Deng Li Qiong
Published: May 2011

In recent years, the magnetorheological (MR) fluid damper-based semiactive control systems have received considerable attention for protecting structures against natural hazards such as strong earthquakes and high winds. In this paper, an improved modal controller integrated with a Kalman-filter observer is proposed for vibration control of spatial structures. The proposed modal controller can reduce the dimension of the control equation and thus can relieve the calculation burden greatly. In the proposed control system, a Kalman-filter observer, which estimates the full controlled modal states from local accelerometer outputs, is designed for rendering the controller to be more applicable to real spatial structures with a large number of degrees of freedom (DOFs). A numerical example of a lattice roof structure installed with MR dampers is presented. The effectiveness of the controller is evaluated under both Tianjin and El Centro earthquake excitations. The simulation results demonstrate not only its effectiveness of reducing vibration of spatial structure, but also its adaptability for versatile loading conditions.
Multi-Degree of Freedom Vibration Theory and Engineering Application
Authors: Huang Min Yuan
Published: May 2011

Regarding the multi-degree of freedom as the research object, we study vibration theory and engineering application of the multi-degree of freedom. Main content as follows: When establishing vibration system model, we deal with the structure’s discretization and the motion simulation, as well as simplify the foundation model and other issues. The establishment of vibration motion equation must combine with the specific situation and ensure the accuracy of equation, so that we can achieve the best equation of engineering fitting. Harm treatment of engineering vibration is the key to enhance structure durability.
Definition of the Ultimate State of the Scooted Head Pile Bearing Uplift Load in Soil Foundation Based on Failure Approach Index
Authors: Zhang Zhen Hua , Yuan Meng Ling , Cui Qiang , Lu Xian Long , Liu Shou Qian
Published: May 2011

The criterion to judge the ultimate state of the scooted head pile bearing uplift load in soil foundation is insufficient at present. According to this problem, a numerical simulation method based on Failure Approach Index considering Mohr-Coulomb yield criterion is adopt to study a quantitative and sufficient criterion for the ultimate state of the scooted head pile bearing uplift load in soil foundation. A scooted head pile in homogenized soil foundation is taken as an example, the ultimate uplift load of the pile is obtained by test, at the same time the ultimate uplift load of the pile is obtained by numerical simulation method based on Failure Approach Index considering Mohr-Coulomb yield criterion. The research results indicate that the two values of ultimate uplift load of the pile obtained by test and the numerical simulation method are very close, which give the sufficient evidence that the criterion for the ultimate state of the scooted head pile bearing uplift load in soil foundation based on Failure Approach Index is sufficient and reasonable.
Shrinkage and Creep Analysis of a Continuous Rigid-Frame Bridge with Density Gradient Concrete
Authors: Lu Zhi Fang , Liu Mu Yu
Published: May 2011

In consideration of the excessive mid-span deflection and box girder cracks of continuous rigid-frame bridges, this paper analyzes the maximum first principal stress and mid-span deflection increment of a continuous rigid-frame bridge with density gradient concrete under shrinkage and creep effect. The maximum first principal stress increment at main span is 0.084MPa and mid-span deflection increment is 73mm after 10 years for continuous rigid-frame bridge with density gradient concrete, which are smaller than a continuous rigid-frame bridge with normal concrete. All of that show that continuous rigid-frame bridge with density gradient concrete reduces effect of shrinkage and creep. The research provides a theoretical basis for the successful application of continuous rigid-frame bridge with density gradient concrete.
Comparative Research on Mechanical Behavior of Column-Bracing System between Fixed-Ended and Pin-Ended Column Base
Authors: Zhao Jin You , Zhang Yao Chun , Guo Xun
Published: May 2011

In order to investigate the different mechanical behavior of column-bracing system between fixed-ended and pin-ended column base, a large number of column-bracing systems with fixed-ended and pin-ended column base were studied using the ANSYS program, in which random combination of the initial imperfections between columns and braces was well considered by the Monte Carlo method. Based on the above comparative study, probability density function of the bracing force was found through probability statistics and the design bracing force is obtained. The results show that the ultimate load-carrying capacity and the bracing forces of the mid-height horizontal braces of column-bracing systems with pin-ended column base are higher than that of column-bracing systems with fixed-ended column base, and the higher ultimate load-carrying capacity of the former more significantly increases the bracing forces of the mid-height horizontal braces; that the bracing forces of the mid-height horizontal braces in compression or in tension have also randomness because of the randomness of the initial imperfection of both columns and braces.
Pit Bearing Capacity Effect to Status of Soil Plug during Pile Driving in Ocean Engineering
Authors: Zhu Ping , Yan Shu Wang
Published: May 2011

Foundation piles of the offshore oil platforms in Bohai Bay are usually longer than 100m with a diameter larger than 2m. Thus, thoughtful drivability analysis has to be performed in the design stage because of the high cost and time limitation. It has been shown that to judge if the soil column inside the pile is fully plugged, which will make the pile behave as close-ended, will strongly influence the accuracy of drivability analysis. Engineering practice repeatedly indicates that the currently widely used methods for soil plug judgment often give incorrect results, leading the designers to make a wrong decision. It has been found that this problem is caused by the ignorance of the bearing capacity provided by the soil surrounding the pile. Based on the Terzaghi’s bearing capacity calculation method for deep foundation, a new approach for judging soil plug status is put forward, in which the surcharge effect has been considered and the dynamic effect coefficient is included. This approach has been applied to some practical engineering projects successfully, which may give more reasonable results than the currently used method.
Bending Behavior Analysis of Composite Girders with Concrete Filled Tubular Flange
Authors: Wang Chun Sheng , Zhai Xiao Liang , Duan Lan , Li Bao Rui
Published: May 2011

In order to study the bending capacity of steel and concrete composite girder with concrete filled tubular flange (SCCGCFTF), a formula for the ultimate bending capacity of normal section was proposed based on perfected elastic-plastic model for steel and restricted concrete model for inner high performance self-compacted concrete. Analysis result shows that the mechanical behavior under static load can be divided into two phases in accordance with confining effects. Confining effects strength of the concrete-filled steel tube flange was relation to the restriction effect coefficient ξ. The ratios of the calculated value to the experimental ultimate bending capacity were between 0.93 and 0.97. Therefore, the theoretical formula is relatively safe to calculate the ultimate bending capacity.
Identification of Near-Field Pulse-Like Ground Motions Recorded at Bajiao Station during the Mainshock of the Great Wenchuan Earthquake
Authors: Li Chun Feng , Li Yong Bo
Published: May 2011

When earthquake occurs, it is in near-fault that the most serious damage happens and velocity pulse appears. Velocity pulse could have huge potential to destroy the structure in near-fault. The set of records at Bajiao Station is one of the three famous near-field sets of strong ground motion records whose PGAs are the largest in all the sets of records obtained from the mainshock of the Great Wenchuan Earthquake. Our research is to identify the pulse-like characteristics from the set of records at Bajiao Station. It is found that velocity pulses in the records are “hidden pulses”.
Directivity Effect in the Peak Ground Acceleration Fields and Attenuation Relations - A Case Study of the Ms 8.0 Wenchuan Earthquake
Authors: Hu Jin Jun , Xie Li Li , Yang Yong Qiang
Published: May 2011

We study the characteristics of ground motion fields and peak ground motion attenuation relations during the 2008 Ms 8.0 great Wenchuan earthquake by using 198 sets of three-component acceleration time history recordings. To provide a comparable result to other earthquakes, we first rotated the east-west (EW) and north-south (NS) orientated ground motion to fault strike normal (FN) and fault strike parallel (FP) directions. Through comparison of the near-field peak acceleration fields and peak acceleration attenuation relations, there obviously exists a rupture directivity effect in the peak ground accelerations. The amplitude in the rupture propagation direction is higher than that of the opposite direction. And the closer the station to the fault plane, the smaller the difference of ground motion amplitude between the two opposite directions.
Comparative Study on Fracture Behavior of the Reinforced Jointed Rock
Authors: Li Ming Tian , Li Shu Cai , Zhang Ning
Published: May 2011

In order to understand the anchorage mechanisms the fracture behavior of jointed rock masses reinforced with rockbolts was compared with those of the jointed rock masses without rockbolts. Firstly the unaixal tensile tests were conducted on the specimens with inclined surface cracks, horizontal through cracks and horizontal a quarter through cracks to investigate the crack growth of the jointed rock masses without rockbolts. The experimental results show the fracture of the specimens without rockbolts belonged to tensile fracture in the catastrophic way under uniaxial tensile conditions. However the experimental results of the specimens reinforced with rockbolts show that rockolts can change the initiation of the pre-existing cracks, incur the secondary cracks and there existed stable crack propagation.
Study on the Chloride Contents of Sea Sand in Ningbo
Authors: Liu Jun Zhe , Chen Jian Bin , Zhang Guo Liang , He Zhi Min
Published: May 2011

This paper is to study the sand concrete, sand is mixed with sand as fine aggregate in concrete, in recent years by large-scale applications in the coastal areas, especially in Ningbo, a coastal river sand shortage is resolved this problem, coupled with low prices, most of the commercial concrete companies are willing to play down the use of sand instead of river sand, the paper surveys and analyzes the use of sea sand in Ningbo and the physical characteristics of sea sand, on this basis, simulates sand chloride doped, dilute sea sand, not dilute sand sea sand and fly ash concrete mortar strength was measured to analyze the strength of law, by comparison analysis, the presence of chloride in the early strength concrete sand.
Calculation Method of the Initial Strains of Cables in Pretensioning Construction of Prestressed Space Reticulated Structures
Authors: He Yong Jun , Zhou Xu Hong , Zhou Jia Wei
Published: May 2011

It is a complicated process to adjust the tensile forces of cables to their target forces in the practical tensioning construction of prestressed space reticulated structure. In this paper a calculation method for whole-process analysis of the multi-stage and multi-batch tensioning construction is presented to improve the tensioning efficiency. By diminishing the difference between the actual tensile forces of the cables and their target values gradually, the initial strains of the cables for tensioning in construction can be obtained. All the cables can reach to their target values one time if they are stretched to the calculated initial strains in accordance with the predetermined tensioning sequence. The analysis on a prestressed spherical reticulated mega-structure with span of 150m is carried out; the results indicate that this method is feasible in practice.
Practical Method for the Pile Composite Ground under Flexible Foundation Based on Super-Substructure Interaction
Authors: Peng Yong Fei , Yu Jian Lin , Gong Xiao Nan , Lv Wen Zhi
Published: May 2011

The technology of the composite ground under a flexible foundation have been widely used in transportation, water conservancy and other departments, yet its theory of characterizing the behavior of the composite ground needs to be further researched. A simplified analytical model is presented, considering the above four parts which includes the flexible foundation, the cushion, the composite ground, and the underlying soils as an interactive system, allowing for the relative movement between piles and soils, and assuming different settlement of foundation soil at the same elevation. The force equilibriums of a typical element are established. And then, according to the compatibility of stress and deformation on the interfaces between these four components, the formulas on settlement and stress ratio of pile-soil, which is used to characterize the behavior of the composite ground, are derived.
Random Process Description on Short-Term Deformation Behavior of Endangered Earthen Heritage Slope under Natural Conditions
Authors: Zhang Jing Ke , Chen Wen Wu , He Fa Guo , Sun Guang Pin , Guo Qing Lin
Published: May 2011

Deformation behavior of endangered earthen heritage slope makes sense to scientific conservation of earthen architecture. It realizes qualitative and quantitative description of diseases. Based on random process and description theory, deformation behavior of endangered earthen heritage slope (Jiaohe Ruins) is studied using high-accuracy, real-time, dynamic information obtained by deformation monitoring appliance. Research result indicates that mathematic model can be established by use of modern mathematic method. The mathematic model of Jiaohe slope proves that short-term deformation behavior owns periodicity (36h) and occasional mutation. Simultaneously, tendency deformation performs weakly. The conclusion lays foundation for the research on quantitative deformation behavior and the following forecasting of similar earthen heritage slope damages.