bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Concrete Spalling Using Changes in Modal Flexibility
Authors: Hajihasani Nadia , Bakhary Norhisham
Published: December 2010

This paper presents a study in the effect of spalling to dynamic parameters such as natural frequencies and mode shapes. Numerical example of a slab is used as an example in this study. The slab will be modelled using ANSYS 11.0 and various types of spalling are imposed. The changes of vibration parameters are monitored and compared. To compare the sensitivity of modal parameters to spalling is determined using the flexibility method. Based on the results it is found that by incorporating mode shapes using flexibility method, damage location and severity can be obtained.
The Feasibility Study on Adding Roof in Square City of the Ming Tomb
Authors: Mu Bao Gang , Wang Yan , Yang Xiao Hua
Published: December 2010

This paper demonstrated the feasibility of the adding roof on Ming Dynasty Castle in the Square City of the Ming Tomb. First, the structure composition of the existing ground in Square City and the wall of Ming Dynasty Castle was proved preliminary, through CT imaging of electromagnetic waves and on-site trench. Second by means of FEM, the stress and deformation of the wall load imposed were simulated. At last, the strain deformation of corridor in long period was monitored by grating sensors. It repeatedly demonstrated that the programs of adding roof on Ming Dynasty Castle can be achieved in the technology.
The Investigation and Analysis of the Use of Rail Fastening in Shanghai
Authors: Shi Rong , He Yue Lei
Published: December 2010

In this paper, rail fastening of shanghai metro line1,2,3,4, the species distribution from a variety of fasteners and fastening performance comparisons of the two main aspects of the investigation. To mastered the main content of the use of Shanghai Metro rail fastening. Analysis of the popular types fastener of Shanghai subway such as type WJ-2 fastener, type DTIII fastener, type DTIII-2 fastener, type II elastic fastener. Track fastener in the actual use of shock absorber characteristics of the process. Come to Shanghai Metro rail fastening design and selection of line with actual needs, Shanghai Metro rail fastening series featured a wide variety and distinctive. Also pointed out that lack of adjustable fasteners, fastener corrosion, fastener and the lack of vibration reduction and performance degradation caused by a wide range of management and maintenance of complex and emphasize on the use of investigation and analysis of search problems, tracking the course of the development, research the causes and improve the conservation measures to maintain rail fastening methods Keti the safe operation of the subway has a crucial role in.
Study of Load Test of Pedestrian Suspension Bridge
Authors: Liu Yun , Yan Dong Huang
Published: December 2010

This study focuses on test loading program and evaluation for pedestrian bridge. On the basis of the finite element analysis, numerical model of Lv River Bridge, which is a steel box pedestrian suspension bridge, is established. Moreover, field static load test is done and the results of tests are compared to the theoretical values. Results show that the measured result fits well with the theoretical result and bridge is in the situation of elastic deformation, and the strength and stiffness satisfy the need of design.
Application Analysis of Structure Deformation Monitoring Prediction Methods
Authors: Zhang Li Ting , Zhang Hao
Published: December 2010

Nowadays structure construction and monitoring, hazard forecasting depends more and more on scientific prediction methods. This paper focus on prediction method, which based on GM(1,1) model of Gary Theory. With a set of dynamic monitoring data from one structure, we introduce the modeling method of old information model, new information model and equal dimension new information model. An analysis of these prediction models reliability is performed to compare these models. The result of these models can predict the structure settlement proved that a suitable prediction method could provide help to structure safety and reduce unnecessary lost.
Early Age Temperature Rise and Thermal Stresses Induced in Concrete Bridge Pier
Authors: Du Jin Sheng , Luo Xiao Feng , Ng P.L. , Au Francis T.K.
Published: December 2010

Heat generation of concrete during hardening causes early age temperature rise, and if the associated tendency of volume change is restrained, thermal stresses would be induced and early thermal cracking would result. This issue should be duly considered in concrete bridge construction as the bridge piers as well as other structural members are typically mass concrete members. In this paper, a real-life bridge pier is selected for study. The pier was instrumented to measure its early age temperature rise on site. Finite element analysis was conducted to evaluate the time variations of temperature distributions and thermal stresses induced in the bridge pier. The measurement and analysis results threw light on the evaluation of risk of thermal cracking and planning of temperature control measures in similar projects.
Research on the Impounding Test of Trial Span of Cao River Aqueduct
Authors: Deng Hua Feng , Guo Jing , Deng Cheng Jin , Lu Tao , Zhu Min
Published: December 2010

Cao river aqueduct is the mark building at main channel of the middle line of the South-to-North Water Diversion Project, of which the 30m span is the largest aqueduct in Asia for its span, and its structure is relatively complicated, which is the large-scale aqueduct that has been designed and constructed for the first time in China with great technical difficulties in structure form. For it will directly affect the safe operation of aqueduct that whether the actual stressing state, deformation conditions, prestress effect and etc. meet the design requirements, the impounding test of trial span was carried out before formal operation. As it can be seen from the test results analysis, aqueduct structure is under a good elastic working condition with about 1.00mm maximum deflection at mid-span and meets the design and specification requirements, which means the structure of aqueduct is reasonably designed, and structure operation is safe and reliable. In the meantime, the stress characteristics and deformation law of aqueduct structure has been mastered more overall and deeply according to the research on the impounding test, which provides important reference for later operation and management.
Study on 45 Steel „Zero Time Holding” Quenching Technology
Authors: Li An Ming , Hu Meng Juan
Published: December 2010

The effect of “zero time holding” quenching temperature on the 45 steel’s microstructure and mechanical properties were studied by the orthogonal regressive principle. The 45 steel’s microstructure characteristics with “zero time holding” quenched were analyzed. The results showed that the 45 steel’s strength and hardness increased with the increase of quenching temperature in the range of 780～ 900°C. The grain size in zero time holding was smaller than that with holding time (60 min). The martensite lath was very fine after “zero time holding” quenched. The mechanical properties of the 45 steel Processed by the zero time holding heat treatment is higher than those processed by the conventional heat treatment. The experimental results showed that the properties of the drive shaft with 45 steel were satisfying after they are processed with the “zero time holding”heat treatment technology.
Dynamic Time-History Deformation Response Analysis of Long-Span Beam Bridge Subjected to Flowing Ice
Authors: Bai Zhi Ping , Zhang Xie Dong , Han Cheng Lin
Published: December 2010

Based on the pile-soil function and damper boundary condition influence by Finite Element Method, taking Bao-Shu yellow river extra long-span bridge as the project object, the deformation effect of the bridge subjected to flowing and melting ice in spring was analyzed considering dynamical action mode. The results revealed that the deformation from this kind of action is tittly small and the bridge structure is reliable and stable. Then the calculation and analysis have been put into design and construction stage.
Experimental Studies on the Superelastic Properties of SMA Material
Authors: Meng He , Yang Kun , Wang She Liang
Published: December 2010

A kind of SMA material with the chemical composition of Ti-51% at Ni (made in china) which is austenitic at room temperature is tested to find out the influences of adding/unloading frequency, loading amplitude and adding/unloading cycles on the superelasitc properties of it. Then the conclusions were made according to the experimental results given in the paper. Finally, some suggestions to improve the performance of the SMA material were offered.
Stress and Strain Concentrations in an Elastic Bar of Circular Cross-Section with Semielliptic Groove Subjected to Tension
Authors: Hou Jian , Yang Zheng
Published: December 2010

The elastic stress and strain fields in a circular cross-section bar with semielliptic groove subjected to uniaxial tension are systematically investigated using the finite element method. It is found that the stress and strain concentrations are different even if the material is in the elastic state. The relation between the stress and the strain concentration factors depends on Poisson’s ratio and the groove’s geometric configuration. The coupled influences of the shape factor of the semielliptic groove and the relative depth of the groove on the stress and strain concentrations are examined. The equations that describe the stress and strain concentration factors for different groove’s geometric configurations and Poisson’s ratios are obtained based on finite element results.
Analysis of Subharmonic Resonance Response of the Time-Delayed System
Authors: Zhang Hong , Wu Xiao Hong , Zhang Lei
Published: December 2010

The subharmonic resonance response of the strongly nonlinear delay differential equation is solved using the incremental harmonic balance method. The value of the exciting frequency when the subharmonic resonance occurs is discussed. The influences of the time delay and the feedback gain on the system subharmonic resonance response are studied. The variation of the subharmonic resonance response with the system parameters is obtained. The results show that the value of the exciting frequency when the subharmonic resonance occurs is affected by the system parameters. The proportion of the one third harmonic in the amplitude increases rapidly with the increase of the exciting frequency. The variation of the amplitude ratio of the one third harmonic and the first harmonic is wavy type. The proportion of the one third harmonic in the amplitude decreases with increasing the displacement feedback gain and increases with increasing the velocity feedback gain. The proportion of the one third harmonic in the amplitude occupies a dominant position in the subharmonic resonance response.
Equidirectional Umbrella Diameter Changing Mechanism for Ultrasonic Inspection of Seabed Pipelines
Authors: Cao Chong Zhen , Wang Feng Qin , Tian Qi Fa , Zhuang Jia Lan , Li Feng Chun
Published: December 2010

Ultrasonic inspection is a key method of inspecting wall thickness flaw of seabed oil pipelines. How to lay out ultrasonic probes to fit for three inner diameter pipelines of Φ195mm, Φ247mm and Φ297mm was analyzed detailed. Diameter changing principle feasibility of ultrasonic inspection adopting 10 parallelogram mechanisms was discussed, and the key parts of structure of equidirection umbrella diameter changing mechanism were analyzed. In the end model machine experiment verified that equidirection umbrella diameter changing technology is feasible.
Performance Analysis of Fire-Resistant H-Beam Steel
Authors: Qian Jian Qing , Chen Ji Ping , Wu Bao Qiao , Wu Jie Ca
Published: December 2010

The fire-resistant hot-rolled H-beam steel is the newly developed structure material. The development situation of the fire-resistant H-beam steel is briefly introduced. The chemical composition, microstructure, room temperature and high temperature mechanical properties and weldability of several batches of the developed domestic fire-resistant hot-rolled H-beam steels are comprehensively analyzed. The results show that the newly developed hot-rolled fire-resistant H-beam steel has very high room temperature strength, certain high temperature strength, good welding performance, but the toughness needs to be further improved. The performance of web and flange of H-beam steel has large gap.
Experimental Study about the Performance of the Piezoelectric Friction Damper
Authors: Zhang Ji Gang , Deng Wen Yan , Han Jian
Published: December 2010

Because of its excellent energy dissipation capacity, friction damper has a wide application in engineering structure, while its use is restricted by constant frictional force. Piezoelectric ceramic actuator has electrochromic deformation ability, by the use of this advantage to combine piezoelectric ceramic actuator with friction damper to form piezoelectric friction damper. This paper conducts some experiments, to study the force output performance and response time of piezoelectric friction damper as well as its hysteretic behavior. The results show piezoelectric friction damper has good force output capacity with the input voltage increases, and the hysteretic behavior is stable, which almost has no relevance with loading frequency.
Effect of Sulfate Ions on the Corrosion Behavior of Steel in Concrete Using Electrochemical Methods
Authors: Shi Jin Jie , Sun Wei
Published: December 2010

The effect of sulfate ions on the corrosion behavior of steel in ordinary Portland concrete (OPC) and high performance concrete (HPC) were investigated. Steel corrosion was evaluated by means of corrosion potential (Ecorr), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS) and cyclic polarization (CP). The electrochemical results indicated that, compared to the pure chloride solution, the presence of sulfate ions in the chloride solution both reduced the time to corrosion initiation and lead to an increase in corrosion rate of steel in OPC specimens; however, the sulfate ions had negligible effect in HPC specimens. Furthermore, the corrosion rate of steel exposed to chloride solution was higher that to the sulfate solution both in OPC and HPC specimens.
X-Ray Computed Tomography Studies of 3D Meso-Defect Volume Distribution Changes of Cement Paste due to Carbonation
Authors: Han Jian De , Pan Gang Hua , Sun Wei , Wang Cai Hui , Rong Hui
Published: December 2010

X-ray computed tomography (XCT), a non-destructive test, was used to study three dimensional (3D) meso-defect volume distribution changes of cement paste due to carbonation. The 3D meso-defect volume from 0.02mm3 ~5mm3 before and after carbonation was analyzed through add-on modules of 3D defect analysis. The experimental results show that the meso-defect volume fraction before and after carbonation are 0.7685% and 2.44%, respectively. After carbonation, the smaller defect increased significantly than the bigger defect.
The Application of Unascertained Theory in Quality Comprehensive Evaluation of Bridge Engineering
Authors: Dong Hui , Gao Quan Chen , Zhang Huai Wen
Published: December 2010

The Minneapolis bridge disaster that happened recently shows, our quality of science of bridge building taking quantitative index as main basis in use evaluates and has certain defects systematically synthetically at present, reflect the actual conditions in order to enable thinking the system can be true effectively, need to introduce into expert's system of judging, utilize its abundant experience to carry on the qualitative judgment to the bridge. This paper makes use of unascertained theory dealt with synthetically systematically to that the expert judge, the ones that avoided evaluating in the work are subjective and random, strengthen the scientific and objective fairness of evaluating the work, thus improve the authenticity of appraising the result.
Reliability Analysis of Earth Slopes Using Differential Evolution
Authors: Kang Fei , Li Jun Jie , Ma Zhen Yue
Published: December 2010

This paper presents a new method to simultaneously search for the minimum reliability index and the critical probabilistic slip surface of earth slopes. By introducing the Hasofer-Lind reliability index, the probabilistic slope stability analysis problem is modeled as a constrained optimization problem. A recently proposed intelligent global optimization algorithm differential evolution with a penalty function is adopted to solve the constrained optimization problem. Numerical results on two slopes show that the propose technique is efficient and practical to reliability analysis of earth slopes.
Environment-Based on Experimental Design of Concrete Structures
Authors: Jin Li Bing , Xiong Xiao Li
Published: December 2010

In order to evaluate and predict the behaviors of concrete structures under the environmental conditions, such as temperature, chloride invasion and earthquake effectively, a new experimental method is presented which can evaluate the field performance of reinforced concrete (RC) structures by measuring the structure in the artificial accelerated environment. The method establishes the similarity-relationship of performance changing between the field and the accelerated environmental conditions by contrasting and analyzing the behaviors changing under both environments, and realizes the effective and exact estimate to the field structures from the indoor accelerated experiments. It brings forward a new way of thinking to test the RC structures under the environmental conditions. We explain the implemental process of the design by taking the experimental design of multi-environment time similarity methodology on RC structures under the chloride invasion as an example.
A Key Parameter in a Novel Fatigue Crack Growth Model
Authors: Gu Li Xiong , Liu Zhi Fang , Xu Zhong Yong
Published: December 2010

The effect of the load ratio, R, or the mean-stress on fatigue life has been recognized for more than a hundred years. In this paper we first describe a novel mechanics model for fatigue crak growth (FCG) under constant amplitude (CA) loading based on static fracture mechanics with thinking about the inertial effect coefficient and its impact to crack tip, and then discuss the relation between R-ratio and fatigue crak growth rate. Comparison of the present analysis with experimental data taken from the literature demonstrates that R-ratio has a greater impact to the fatigue crack propagation.
Prediction of Chloride Ingress into Concrete by Capillary Absorption
Authors: Wang Li Cheng
Published: December 2010

In this paper, the lattice network model on mesoscale is established based on the random geometry meshing technique to investigate the chloride ingress into unsaturated concrete. Concrete is treated as a composite material with three phases, i.e., the coarse aggregates, the mortar, and the interface between them. The diffusivity for water and chloride in each phase of the mesoscopic structure of concrete is separately quantified by experimental data or through empirical assumption. The numerical predictions are compared with the available experimental measurements. The comparisons indicate that numerical predictions agree well with the test results.
Study on Shrinkage of Concrete Based on BP Neural Network
Authors: Wang Tie Cheng , Peng Quan Min , Liu Wen Liang , Feng Li Feng
Published: December 2010

In order to solve the problem of concrete cracking in wellhead groove with large longitudinal length, shrinkage tests of concrete containing fly ash and slag in natural environment were conducted. According to the experimental study, the shrinkage model of concrete based on BP neural network is established and the results from model agree well with the measured results. Then the effect analysis of single factor on shrinkage using the neural network model is carried out. Simultaneously, the optimal mix proportion of concrete is successfully predicted by orthogonal experiment of numerical simulation method, so that it provides reference to the control of concrete shrinkage for the engineering structure.
Durability of BFRP and Hybrid FRP Sheets under Freeze-Thaw Cycling
Authors: Shi Jia Wei , Zhu Hong , Wu Zhi Shen , Wu Gang
Published: December 2010

Coupon tests were conducted to investigate the mechanical characteristics of basalt FRP (BFRP) sheet, basalt-carbon hybrid FRP sheets and the corresponding epoxy rein under the effect of freeze-thaw cycling. FRP sheets and epoxy rein coupons were subjected to up to 200 and 250 freeze-thaw cycles respectively. Test parameters included the number of freeze-thaw cycles and the types of FRP composites. Test results show that (1) BFRP sheet perform better than CFRP or GFRP sheets under high freeze-thaw cycles; (2) exposed hybrid FRP sheets not only show very little loss in mechanical properties, but also contribute to the stability of test data; (3) mechanical properties of rein epoxy decrease significantly with increasing freeze-thaw cycles.
Durability Evaluation Analysis of Reinforced Concrete Structures Based on Extension Method
Authors: Liu Jun Zhong , Xu Jin Yu , Bai Er Lei , Gao Zhi Gang
Published: December 2010

Because of the facts of reinforced concrete structures materials and used environment, very severe durability problems occurred in reinforced concrete structures. Research on reinforced concrete structures durability has become one of the world-wide concern problems in structural engineering. Extension method based on matter-element theory and conjunction function is introduced to evaluate durability of reinforced concrete structures in this paper. The matter-element model for durability evaluation of reinforced concrete structures is established by chose seven evaluation indexes. Applying simple conjunction function to calculate the weight coefficient of evaluation indexes can reduce the error caused by subjective judgment, and makes the results more objective. The research indicates that extension method is reasonable and feasible in evaluating durability of reinforced concrete structures.
The Ultimate Bearing Capacity Analysis of P.C. Bridge Based on Material Performance Degradation
Authors: Xue Peng Fei , Mao Da Ling , Wang Jin Feng
Published: December 2010

During the service process of a P.C. bridge, the mechanical properties of materials (including concrete and steel) will deteriorate, and eventually result in the decrease of ultimate bearing capacity. Considering it’s structural behavior, degenerate solid elements were used to set up a three-dimensional model. By taking prestressed reinforcement as a part of structure, the equivalent nodal load was provided to calculate the effect of tensioning bars. The T.L. method was adopted to consider the geometric nonlinear effect. The Ohtani & Chen model was used to simulate the concrete material nonlinear behavior, and for prestressed steel strand and common reinforced, linear hardening and ideal elastoplastic model were adopted respectively. A P.C. continuous rigid frame bridge was employed for the case study, on the basis of material performance deterioration, the ultimate bearing capacity analysis of P.C. bridge structure was carried out. The results show that material deterioration has great impact on ultimate load capacity of structure: the load factor on limit state dropped rapidly from 13.9085 at t=0a to 7.8265 at t=100a, the corresponding safe index decreased from 2.265 to 1.581, and brittle characteristics was aggravated at the same time.
Research on the Process of Concrete Damage under Frost Action
Authors: Ma Kai Zhi , Hou Jian Guo , Jia Ji Yao
Published: December 2010

This paper summarizes the theories of the concrete damage under frost action. Based on experiments done by researchers in and abroad, the water conversion and the moisture content change in the concrete during the freeze-thaw cycles are analyzed. In this paper, the affection of the expansion and contraction of ice on concrete at temperatures in the usual freeze-thaw test range is particularly taken into consideration. At last, a qualitative process of the concrete damage under frost action is proposed.
Research on Stress-Strain Curves of Steel under High Temperature
Authors: Tong Huai Feng , Dai Dong Liang
Published: December 2010

The effect of fire is the most important factor in steel design, in this paper, the existing steel structure fire resistant design methods are analyzed, and pointed out the shortcomings of various methods, through the research of fire resistance properties of steel and reference to European standards, the stress - strain properties of common steel under high temperature were analyzed and calculated, and the ease to use of stress - strain relations were obtained.
Analysis of Subsidence and Bearing Capacity of Consolidated Ground
Authors: Wang Zhong Chang
Published: December 2010

There is high requirement to the foundation of the raceway of container gantry crane. However, the marine soft soil is distributed extensively at Dalian ports. In the paper, the settlement and bearing capacity of natural and composite foundation of raceway of container gantry crane under design load is analyzed by finite element method on the basis of geological data, foundation treatment. The relationship of different deformation modulus and foundation bearing capacity is obtained by considering the strength of foundation and the requirement of settlement. The settlement and the inclination value of two sides of container gantry crane which is less than the permitting value of laws under consolidated ground and corresponding load condition is obtained. The corresponding deformation modulus of consolidated ground is obtained under different load condition. The boundary of basis is easy to failure, the treatment range extension of foundation should be considered.
Nonlinear Analysis of Structures Supported on Hysteric-Friction Isolation System with Elastic-Plastic Displacement-Constraint Device under Main Shock and Aftershock
Authors: Zhao Gui Feng , Ma Yu Hong
Published: December 2010

The hysteric-friction isolation system with elastic-plastic displacement-constraint device is put forward. The action mechanism and restoring force model of the elastic-plastic displacement-constraint device are analyzed. The nonlinear seismic responses of structures supported on Hysteric-friction isolation system with elastic-plastic displacement-constraint device under main shock and aftershock are researched. The results indicate: the displacement-constraint device not only can ensure the upper structure safety, but also can effectively limit the displacement of the isolation layer, meanwhile can supply secondary protection under strong aftershock. The structure of the device is simply, which is convenient for production and installation. Meanwhile because the device is cheap, it can be widely used in isolation building.
Research on Mechanisms and Ground Uplifting Effects by Grouting Taken the Grouting-Soil-Building Interaction into Account
Authors: Wang You , Wang Xing Hua , Zhang Min
Published: December 2010

As excavation and precipitation involved in the foundation works will cause subsidence of the building foundation surrounding, grouting uplift technology is widely used to control settlement. In this paper, relied on rectification of one building, a three-dimensional finite difference model of grouting-soil-building interaction is established. Based on the method of imposed volumetric strain, the uplift process of grouting is simulated by expanding cell volume applied radial velocity to the grid nodes on the spherical slurry bubble. The variation regularity of surface deformation uplift, upper building deformation and internal forces on various stages of strata grouting are discussed and analyzed, and compared with the data on-site monitoring. The results show that the measured values and calculated values are in a good agreement. The method of applying the node speed to simulate non-uniform spherical expansion of multiple slurry bubble may predict the grouting uplifting preferably and provide a reference for design of grouting uplift and building rectification in the future.
Analysis of Relationship between Pile Quality and its’ Bearing Capacity
Authors: Wen Xiao Gui , Sun An , Wu Hui Ming , Wang Wen Tao
Published: December 2010

Bored pile is one of the most widely used foundation forms in civil engineering. Relationship between pile quality and its’ bearing capacity is seldom been discussed. This paper introduces 8 bored piles in one storage tank project in Ningbo, of which 4 piles are done vertical load tests; the other four are done lateral load tests. Combined with their quality, the results reveal that when load is small, pile quality has much influence on pile bearing capacity. As soon as load is large enough to transfer to pile bottom, quality of concrete at pile bottom becomes the main factor that impacts pile vertical capacity, meanwhile pile horizontal bearing capacity mainly depends on pile length. Post-grouting is done to improve pile quality. It raises pile’s bearing capacity while reducing differential settlement at the same time.
Reliability Analysis and Design Suggestion of Concrete Structure Bonded Rebars with Inorganic Material
Authors: Liang Yu Guo , Gao Tian Bao , Deng Yu
Published: December 2010

Based on the established limit state equation and connected with a large amount of statistic analysis of testing data, central point law in first order second moment method (FOSM) is adopted to the reliability analysis of bonded rebars with inorganic material. The adhesive anchorage design suggestion of bonded rebars with inorganic material is proposed. By means of comparing the calculation results to experimental results, it can be concluded that the calculation methods of anchorage length can be used to the calculation of designing concrete bonded rebars.
Experimental Investigation on Anchorage Mechanisms of Self-Locked Anchor under Combined Tension and Shear
Authors: Li Ying , Pan Dong Zi , Zhang Lian
Published: December 2010

Self-locked anchor is a new type of underreamed anchor, and which is more and more frequently used in both new construction and structural retrofitting or strengthening projects. Nevertheless, current design codes do not contain suitable design recommendations for these anchors. This study investigates the anchorage mechanisms of self-locked anchor under combined tension and shear loadings. The experimental parameters mainly include anchor diameters (Φ16 and Φ20) and loading angles (0°, 30°, 45°, and 60°). The present results indicate the characters of axial and transverse deformations, the ultimate bearing capacity, the fracture pattern of anchor, and the breakout model of concrete.
Experimental Study on the Steel Bar/Wire Mesh Reinforced Preplaced Aggregate Concrete Composite Strengthening of Concrete Square Columns
Authors: Li Hai Jun , Zhen Zheng , Liang Chuan Hao , Dai Ming Sheng , Lu Xiao Hua
Published: December 2010

The authors propose a structural strengthening method combining the concepts of preplaced aggregate concrete (PAC) and steel wire mesh reinforce mortar strengthening. The steel bar/wire mesh reinforce preplaced aggreate concrete (SWPAC) composite structural strengthening is targeted at cases where large increase of structural resistance are required, sectional enlargement is restraint and hash fire protection and durability requirements. The preliminary experimental study shows that the proposed structural strengthening method is practically feasible. The strengthened structure is ductile enough to work as structural members. For thin layer strengthening, lateral confinement of the strengthening concrete would be a key topic for later investigations.
Applications of Muti-Ribbed Walls in the Strengthening of Masonry Structures with Bottom Frame
Authors: Chang Peng , Zhai Chang Yi
Published: December 2010

As a new kind of structures, Multi-ribbed wall structure is now widely used in new-built buildings and old structures needed to be strengthened. In the field of strengthening, Masonry structure with bottom frame is often mentioned for it is vulnerable to earthquake. However, it is still widely applied in China for its agility for arrangement. So how to guarantee the safety of this kind of structure is very important. There are many methods to reinforce this style of structure, but every way has its limitations. Compared with other methods, Multi-ribbed wall structure is more proper, because its stiffness and mass can easily be changed through optimal design of different kinds of materials inside.
Centrifuge Model Tests on Geotextile-Reinforced Slope in Situation of Excavation
Authors: Li Ming , Zhang Ga , Lee C.F. , Zhang Jian Min
Published: December 2010

Excavations on steep slopes are common problems in practice; little work has been done on the geotextile reinforcement effect in such a situation. Two centrifuge model tests were conducted to simulate the excavation of cohesive slopes with and without reinforcement. The tests results showed that the geotextile greatly enhanced the slope stability and the effects of reinforcement mainly emerge in two aspects as follows: (1) to diminish the deformation and to unify deformation distribution; (2) the reinforcement effect was achieved mainly through friction forces.
Numerical Simulation of Bolted-Steel Plates Strengthened Coupling Beams
Authors: Zhu Yong , Zhou Yun , Zhu He
Published: December 2010

One reinforced concrete coupling beam and two strengthened reinforced concrete coupling beams by bolted steel plates are analyzed by nonlinear finite element method. Two-dimensional finite element model is employed with material nonlinearities and geometrical nonlinearities. A special ring region, which simulates the slip effect between concrete and steel plates, is developed an incorporated into the numerical analysis model. The load-displacement relationship, cracking/crushing type and steel plates internal are compared and found to be in good agreement with those in test.
Research on the Effect of Injury Beams Strengthened with Carbon Fiber Reinforced Polymer (CFRP) of the Unloading Degree
Authors: Zhao Shao Wei , Fu Shi Feng , Xu Zeng Zhao
Published: December 2010

The static load test is done on 5 concrete beams. One beam is loaded to the destruction as a contrast specimen, and the other 4 are loaded to the predetermined damage load (80kN), then unloaded to the different load level separately, keeping the load invariable, and tested the improvement in flexing resistance after structural strengthening by CFRP.The research indicates: The ultimate capabilities of the reinforced concrete beam specimens reinforced by carbon fiber sheets can increase 20.93%~39.80% compared with the specimen without CFRP.
Degree of Monolithic Secure and its Application in Aseismic Strengthening of Existing Engineering Structure
Authors: Duan Jing Min
Published: December 2010

Every earthquake always cause serious destruction of engineering structure , and bring about disastrous heavy losses to society economy. In view of confusion phase of reinforcement philosophy and method in existing engineering structure now, the paper analyses wreck of existing engineering structure as a result of the earthquake, put forward “Degree of Monolithic Secure” thought and probe into its application in aseismic strengthening of existing engineering structure. The “Degree of Monolithic Secure” means using the human being’s thinking and judgment, deciding the fundamental question, conception, and principle of engineering structural reinforcement in macrocosm, on the basis of its essence characteristic and purpose request. The Strengthening philosophy emphasize fundamental of three-dimension conception, spatial function, receiving the strength rationally, coordinating the deformation. It expound basic conception of self-organize theory, whole pre-stressing Strengthening technology directed by Degree of Monolithic Secure.
Boundary Condition Updating of Bridge Structure Based on Mode Parameters
Authors: Shi Zhou , Zhao Ren Da , Qin Shi Qiang , Gao Yu Feng
Published: December 2010

According to the complex boundary condition of real bridge structure, appendix restraint parameters of structure boundary condition were detailed analyzed. The appendix horizontal and torsional restraint parameters were selected as research object. The least square constrained optimization inversion method was used to establish the question of reverse of bridge structure boundary appendix parameters based on tested and calculated mode parameters. The first order perturbation of eigen-value and eigen-vector based on matrix perturbation theory were substituted into the constrained optimization inversion equation, so the solving efficiency was improved greatly, and the iteration method was used to improve the precision. The corresponding program was made, and the example of a maglev railway girder shows that fairly well precise bridge structure boundary appendix parameters can be reserved with only former several modes parameters through four to seven times of iteration calculation.
Experimental Study on Anti-Seismic Restoration of Rowlock Walls
Authors: Tang Wei Min , Li Xiao Bing , Sun Lin Zhu , Jin Guo Ping , Li Zhao Hui , Zhang Qing Hua
Published: December 2010

Based on pseudo-static test of rowlock wall with different constructional measures by MTS loading system, the position of initial crack, distribution of crack, cracking load, failure load, failure state are studied, in order to provide test basis for the determination of economical and effective construction measures for rowlock wall. The test results show that the cracking load and failure load of rowlock wall reinforced with constructional column and tie bar, or with constructional column and horizontal reinforced concrete band,were increased significantly compared with rowlock wall without reinforcement measure. The reinforced rowlock wall has better ductility, whereas rowlock walls without reinforcement measure show obvious brittleness.
Mechanical Behavior of FRP-Confined Rectangular Concrete Column
Authors: Wu Ping , Yu Feng
Published: December 2010

According to the analysis of existing experimental data, it is well known that the behavior of FRP-confined rectangular concrete column were mainly related to the cross section coefficient of concrete, the confinement effect coefficient and the strength of concrete. Based on experimental study and theoretical analysis, the formula for bearing capacity and ultimate axial strain of FRP-confined rectangular concrete column were proposed, and the stress-strain model with strain-hardening components or strain-softening components. The effects of every parameter on the stress-strain relationship were carefully considered. The predictions of the model agree well with test data.
Local Stiffening of Steel I-Beams by Using CFRP Materials
Authors: Narmashiri Kambiz , Jumaat Mohd Zamin , Ramli Sulong Nor Hafizah
Published: December 2010

This paper reports the experimental studies on the local stiffening of steel I-beams by using Carbon Fiber Reinforced Polymer (CFRP) strips. One of the problems which frequently occur for steel section is the large local deformation under point loads. To study the effects of applying CFRP for local stiffening, four steel I-beams were selected and tested to failure. The first beam had no steel stiffeners below the point loads and used as the control beam. The second beam had steel stiffeners and was not enhanced by using CFRP strip. The third and fourth beams had no steel stiffeners below the point loads and were strengthened on the compressive flanges by using two longitudinal CFRP strips. Also, the third and fourth specimens were strengthened on the web by using the latitudinal CFRP strips in the discrete and continual types, respectively. The results show that applying CFRP on the compressive flange and web increased the load bearing capacity and decreased the local and overall deformations appropriately. Also, the full-covering of the web seems to be the best type of web strengthening.
Test Research of Prestressed Concrete Beams with CFRP under Low Cyclic Loading
Authors: Jiang De Bao , Gu Xiao Jing
Published: December 2010

Through testing it is obtained that force and the damage that 1 root structure of prestressed concrete beams strengthened and 3 different layers CFRP reinforced stickup prestressed concrete beams under cyclic loading. This test results show that CFRP reinforcement effect of prestressed concrete beams is obvious, and at the same time the cracking of prestressed concrete beam has also has certain reinforcement effect; But the CFRP reinforcement effect is proportional to the number of layers.
Analysis on Aseismic Performance of the Beijing Yintai Center
Authors: Zhang Zhi Qiang , Li Ai Qun , Sun Yong , Huang Meng Ya
Published: December 2010

In this study, the seismic behavior of the main tower building of Beijing Yintai Center is presented with regard to the dynamic characteristics analysis and seismic response analysis. Firstly, by means of three-dimensional finite element analysis software, the dynamic properties and seismic responses under frequent earthquake action of the structure are obtained, respectively. It can be seen that the structure has a rational arrangement for structural elements and has a good seismic behavior. Then, the seismic behavior of the structure is studied through the dynamic elasto-plastic analysis method and static elasto-plastic analysis method under rare earthquake. Analysis results of both analysis methods show that the behavior of the structure accords with the earthquake performance objectives and the structure would not collapse under the rare earthquake action.
Wind Speed Profile and Gradient Height in Typhoons Observed by Vehicular Doppler Radar in South China
Authors: Li Li Xiao , Xiao Yi Qing , Song Li Li , Qin Peng
Published: December 2010

The recent development of Doppler radar sensor has allowed to study the typhoon wind structure more accuracy and systematic. In order to obtain more wind data near typhoon eye-wall, vehicular Doppler radar emerge as the times require. Based on two typhoon observed results carried out by vehicular Doppler radar in category A terrain, firstly the 10min mean wind profiles under 1000m height in different regions of typhoon were analyzed. The typhoon mean wind speeds increase a logarithmic law with height at nearly lower two hundred meters in all regions of typhoons. Using the power law to fit wind profiles, the exponential index α in pre-eye-wall region is greater than it in post-eye-wall region, and it decreases with increasing the mean wind speed. Secondly, based on analyzing the relationship between mean wind speed and wind ratio, the calculation formula for nominal gradient height were established in category A terrain. Finally introducing the probability method to study the mean wind profile, the exponential index α was established in category A terrain.
In-Plane Cyclic Test on Framed Dry-Stack Masonry Panel
Authors: Lin Kun , Totoev Yuri Z. , Liu Hong Jun
Published: December 2010

A new masonry system has been developed to improve the seismic behaviour of RC frame with masonry panels. In this system dry-stack masonry panels are built with masonry units capable of sliding in-plane of a panel. These masonry panels have reduced in-plane stiffness but increased frictional energy dissipation capacity compared with the traditional masonry panels. Under seismic or wind loads these panels do not detrimentally interfere with natural RC frame response but rather positively contribute to it mainly by increasing dumping. A cyclic test has been performed to evaluate the behaviour of this masonry system. Test results demonstrate that the new system can improve the seismic behaviour of RC frame structures with masonry panels.
Large Eddy Simulation of Wind Field around Large-Span Cantilevered Roofs
Authors: Li Chong Yang , Wei De Min
Published: December 2010

Large-span cantilevered roofs are wind sensitive structures, this paper presents the finding of large eddy simulation(LES) of turbulent wind field around large-span cantilevered roofs with grandstand in atmosphere boundary layer. For a typical horizontal cantilevered roof, the wind pressure is researched in fluid mechanic view, the large scales of wind motion are computed explicitly while the small scales are modeled by LES, the contours of wind pressure and velocity are present to reveal the coherent structures. Some general issues related to LES in wind engineering are discussed also.
Nonlinear Analysis of Eccentrically Loaded Concrete Filled Circular Steel Tubular Columns
Authors: Xia Song , Qin Ai Min
Published: December 2010

Based on the appropriate numerical constitutive model of concrete filled steel tubes, layered method was applied and fiber model method based on partial sinusoidal shape for concrete filled circular steel tubular (CFST) columns under both concentric and eccentric loading was proposed. Utilizing the relationship between the curvature of the worst section and sinusoidal amplitude, a FORTRAN program was developed and the behavior of CFST columns under concentric loading, eccentric loading of equal end-moment and unequal end-moment were analyzed, showing that the analysis results are in good agreement with the experiment results from references and the fiber model method can reflect the load capacity and deformation of the columns reasonably. Thus the reliability of the present method was validated and this work is the basic for the further researches on the practical expressions of load bearing capacity for the CFST columns under both compression and bending.
Dynamic Characteristics Research in Frame Structures Subjected to Vertical Vibration
Authors: Nie Zhi Hua , Liu Hong Bing , Liu Kai
Published: December 2010

The traditional analysis method about dynamic characteristics with frame structures was building story models instead of structures. In this paper, the series-parallel-connection models with considering joint rotation on frame structures subjected to vertical vibration were presented, and the result what’s computed between the two models was compared, a notion called “natural frequency zone” was advanced. At last, some conclusions on the frame structures subjected to vertical vibration were obtained.
Estimating Seismic Energy in Structure with Wavelet Transform
Authors: Xiao Mei Ling , Ye Liao Yuan , Li Yun Fen , Li Yan
Published: December 2010

This study proposed a wavelet method for estimating seismic energy in single-degree-of-freedom (SDOF) structure. With the recent development of wavelet-based procedures for structure seismic response, which the displacement and velocity of linear SDOF structure can be expressed with wavelet transform of acceleration process, it is easy to estimate seismic energy in SDOF linear structure, and strain, kinetic, damping energy and energy input based on wavelets introduced in a range of time and frequency assigned to the wavelet coefficient, Expressions have been derived for (i) the equation of motion. (ii)the wavelet coefficients of the response processes. By using these principles, a linear SDOF structure which subjected to 1988 LanCang-GenMa earthquake ground motions is analyzed, time-histories of strain, kinetic, damping energy and energy input for various ranges of frequencies are identified.