bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Soil Microbial Characteristics of Elsholtzia harchowensis in Copper Mine
Authors: Xiong Shui Ying , Huangfu Jia Kang , Wang Shen Wei , Qiu Mu Qing
Published: April 2014

In this paper, soil microbial characteristic of Elsholtzia harchowensis in copper mine were reported. The results indicated that metal element contents of Elsholtzia harchowensis were: Cu>Zn>Pb>Cd. There were significant correlations in Cu contents between Elsholtzia harchowensis and soil in copper mined tailings region. The Elsholtzia harchowensis possessed obviously different soil microbial features. The intensiver in microbial basal respiration strength, and higher microbial ecophysiological parameters, but lower in soil microbial biomass. The results showed that soil microbial community structure was obviously changed in the Elsholtzia harchowensis system, and much more consumed rapidly carbon sources, but the lower in the ratio of utilization compared with the control test.
Application of Progressive Teaching Model in Engineering Hydrology and Hydrologic Calculation
Authors: Meng Xiao , Cheng Wu Qun , Wu Xian Bing
Published: April 2014

Engineering hydrology and hydrologic calculation is a core professional course of agricultural hydrologic engineering, in order to realize the implementation of quality education in higher school teaching purposes, with the teaching practice of engineering hydrology and hydrologic calculation, puts forward the progressive teaching mode of engineering hydrology and hydrologic calculation, and applied in teaching activities. The conception of progressive teaching mode and practice was summarized from four aspects of progressive teaching objective, teaching content, gradual progressive teaching method, and progressive ability.
Teaching Innovation and Exploration of Principles and Applications of Transducer Course Based on CDIO Idea
Authors: Chen Ru Qing
Published: April 2014

The course teaching pattern reform is conducted in order to solve the problems existing in the teaching progress of principles and applications of transducer course for measurement & control technology and instrument specialty. According to the teaching idea of CDIO, the project item teaching method is introduced in course teaching. Theoretical and practical teaching schemes are designed and the teaching process and evaluation mode are optimized then. After the exploratory research of theory and practice teaching, a set of course teaching system for principles and applications of transducer course is formed based on the concept of CDIO. Curriculum reformation combines classical measure theory with modern test technology properly as well as considers its theory and application, remarkable teaching effect is obtained then. It provides a new teaching method suitable for principles and applications of transducer course.
Study on Dynamic Characteristics of a New Space Latticed Shell String Structure
Authors: Yao Yun Long , Ma Guang Ying , Dong Shi Lin
Published: April 2014

Latticed shell string structure with inner and outer truss torus, radial cables of which emerge from the roof, is proposed. Ribbed latticed shell string structure with a span of 100m is taken as an example and the modal analysis is performed. The effects of the rises of radial cables and the curvatures of latticed shell on dynamic characteristics of this structure are also investigated. The result reveals some characteristics of modal of the latticed shell string structure with inner and outer truss torus, which could be referenced by structure designers.
Study on New Reinforcing Method of Composite Beam with Web Openings under Negative Moment
Authors: Liao Wen Yuan , Zhou Dong Hua , Han Chun Xiu
Published: April 2014

Due to web opening, stiffness and strength of steel composite beam decrease significantly. The common reinforcing method is setting stiffeners around the opening section; the paper presents two methods: herringbone stiffener and diamond stiffener. The finite element model is established with both material and geometrical non-linearity. Compared with other common methods, these two new methods are effective. Some reasonable suggestions are proposed for engineering application.
The Dynamic Characteristic and Response's Discussion of External Prestressing Curved Beam
Authors: Huang Min Yuan
Published: April 2014

The main contents of dynamic characteristic and response of external prestressing curved beam are as follows: The research is about frequency characteristic of external prestressing curved beam. With analysis of variable regulation, the natural frequency's theoretical formula can derived from natural vibration frequency under structure concrete damage .Resonance prevention of external prestressing curved beam is vital. Through explicit beam frequency, external cable and external excitation, and the relationship between above each other can prevent resonance destruction .By analysis of dynamic performance's parameter sensitivity , external prestressing curved beam can be obtained sensitivity parameter of dynamic performance .Model test study of dynamic external prestressing curved beam is also critical. Based on research achievements of existing theory, dynamic model test can be carried on, which would obtain vibration regulation of verification and comparison with structure data.
The Numerical Simulation Experiment of Exploded in the Flat Box Sealed Structure
Authors: Wen Zhu , Jia Bin , Liu Tong , Tao Jun Lin
Published: April 2014

Basis on the theory of mechanics of explosion, according to nonlinear finite element method shows that dynamic analysis software ANSYS/ls-dyna , the explosion wave propagation in the flat box sealed structure and the distribution of overpressure on the wall is studied under the action of explosion. Combining the reality of [Guo Zhikun experiment and basic data , ANSYS/ls-dyna is used to establish a standard size 4 studio flat box experimental model, within the model corresponding to the positioning of the drug to 220 units of TNT. Through ANSYS/ls-dyna visualization process study the transmission mechanism of shock wave in a flat trunk, acquisition of some points on the wall of the overpressure peak data caused by explosion, combined with experiments of the proceeds of the actual data values were analyzed.
Exterior-Template Design for Concrete Engineering in an Arched Structure
Authors: He Dong Qing , Wu Wei Hua
Published: April 2014

In accordance with the technical specifications of existing concrete structure construction template and an arched structure concrete pouring process, the exterior-template design for concrete of the project has been done, which contents the requirements of the of engineering concrete on construction quality.
A DE-Based Algorithm for Structural Damage Detection
Authors: Fu Yong Ming , Yu Ling
Published: April 2014

The development of a methodology for the accurate and reliable assessment of structural damages, as one crucial step in the structural health monitoring (SHM) field, is very important to ensure the safety, integrity and stability of structures. An improved adaptive differential evolution (IADE) algorithm is proposed for structural damage detection (SDD) based on DE algorithm and FE model-updating techniques. An objective function is defined as minimizing the discrepancies between the experimental and analytical modal parameters (namely, natural frequencies and mode shapes). It is set as a nonlinear least-squares problem with bound constraints. Unlike the commonly used line-search methods, the IADE approach, a heuristic method for the direct search of the optimal point of the given objective function, is employed to make the optimization process more robust and reliable. Some numerical simulations for single and multiple damage cases of a 25-bar space truss frame structure have been conducted for evaluation on the reliability and robustness of the proposed method. The illustrated results show that the IADE algorithm is very effective for SDD. It can not only locate the structural damages but also quantify the severity of damages. Regardless of slight damage or multiple damages, the identification accuracy is very high and noise immunity is better, which shows that the IADE algorithm is feasible and effective for SDD.
Construction Monitoring of Prestressed Concrete Continuous Beam Bridge
Authors: Li Cong Qi , Ge Wen Jie , Cao Da Fu , Wang Bi Yuan
Published: April 2014

The creep of concrete structure has a prodigious effect on bridge alignments and the stress control during the bridge construction. In the meantime, the problems such as pre-stress losses, bearing asymmetry sink ,the concrete box-beam deflection, box-beam web cracks, structure stress redistributing and so on, which make the bridge structure lose functions or even invalid early when it works. For these reasons, the construction monitor of the deformation and the long-term deflection of long-span bridges with high piers have important practical significance. Construction monitoring of prestressed concrete continuous beam bridge - new Tongyang canal bridge which adopt cantilever construction work is made.
Moving Force Identification Based on Firefly Algorithm
Authors: Pan Chu Dong , Yu Ling
Published: April 2014

Based on firefly algorithm (FA), a novel method is proposed for moving force identification (MFI) in this paper. The basic principle of FA is introduced, some key parameters, such as light intensity, attractiveness, and the rules of movement are defined. The inverse problem on MFI is transformed into a constrained optimization problem and then can be hopefully solved by FA. In order to assess the accuracy and the feasibility of the proposed method, a beam-like truss bridge subjected to moving forces is taken an example for numerical simulation. The robustness of the method is also evaluated by adding noise into the structural responses. The illustrated results show that the proposed method can accurately identify two moving forces from incomplete structural response at only one strain sensor with stronger robustness.
Static Monitoring and Non-Destructive Test of a Historic Damaged Palace
Authors: Boscato Giosuè , Dal Cin Alessandra
Published: April 2014

The City Hall of Mirandola was stricken and damaged by Emilia-Romagna earthquake sequence of May 2012. This paper presents the procedure for the structural monitoring control of a masonry historic building that presents a serious damage pattern. Structural monitoring was carried out with transducers installed to control the serious cracks that regards the main volumes of the building. The global structural health monitoring was useful to define the actual condition of the dynamic behavior of the damaged construction that are subjected to different mechanism. Ground penetrating radar allows to detect the depth of the cracks and the condition of the masonry. These researches are useful also for the structural future rehabilitation and to define the possible changes in the structural behavior.
Structural Damage Detection by Fusion of GA and PSO
Authors: Yu Ling , Fu Yong Ming
Published: April 2014

In order to solve the inverse problem on structural damage detection (SDD) in the field of structural health monitoring (SHM), a FGAPSO algorithm is proposed by a fusion of the genetic algorithm (GA) and the particle swarm optimization (PSO) in this study. For improving the simple GA with drawbacks of easy precocious and of lower computation efficiency, the real-coded GA is implemented, the chaotic logistic mapping is chosen for initializing population, the self-adaptive crossover-mutation operators and elitist strategy are employed. The GA is then mixed with the PSO algorithm for the population diversity and convergence by exchanging genes between two new populations internally and the goal of improving GA is attained at last. Further, some numerical simulations on a 13-bar planar truss structure with several damage cases have been carried out for assessing the performance of the FGAPAO. The illustrated results show that the proposed FGAPSO algorithm is better than any of conventional GA and PSO. Even for the slight damage case, it is still more feasible and effective for SDD.
Test of Thick Rubber Bearings on its Compressive Properties
Authors: Chen Hao Wen , Pan Peng , Liu Jun Cai , Sakurai Yu , Nakamura Masahiro , Murota Nobuo
Published: April 2014

Vibration is an important comfort issue for the metro surrounding buildings. Among the many methods of subway vibration control, building isolation is the necessary supplement to the track isolation for metro surrounding buildings with sensitive constructive forms or specific comfort needs. Laminated rubber bearings are widely used for the building isolation. In order to further improve the isolation effectiveness, researchers intend to use laminated rubber bearings with relatively thick rubber layers. However, the frequency dependency and temperature dependency are not well explored for the thick rubber bearings. And since constrains from the steel plates to rubber layers are relatively small for thick rubber bearings, its not clear if it is accurate to simply apply the equations for common laminated rubber bearings to the thick ones. In this paper, a compressive properties test is carried out for both thick and thin rubber bearings. Both thick and thin rubber bearings are manufactured by a kind of High Damping Rubber (HDR) and a kind of Nature Rubber (NR). The frequency dependency and temperature dependency are tested. The accuracy of applying the current design equations to thick rubber bearings is discussed based on the test results.
Edge Detection Technology and its Application in the Model Test of Vehicle Bridge Coupled Vibration
Authors: Wu Jing , Yuan Xiang Rong
Published: April 2014

At present, point sensors are mainly used in the measurement of the vehicle and bridge coupled vibration system. And only limited points of the system are measured. Test results can not be compared with calculated and analyzed results in the full field of the system. In the model test of the vehicle bridge vibration, test video is captured with a camera, each frame of the video is processed by the sub-pixel edge detection techniques to identify the deformation of the beam at each time, and the time history of the vibration response at each point of the beam. The model test results are compared with the calculated results of the vehicle bridge coupled vibration system. It is shown in the comparison that the beam deformation curves of both the test and analysis at each time are agreed quite good, and the time history responses of each point of the beam are also in good agreement. It means that the application of the video detection techniques in the vehicle and bridge coupled vibration model test is successful. Taking into account the advantages of the full field high density measurement and the synchronized measurement of the moving vehicle and bridge, further research and extension on the video detection technology are necessary.
Critical Application Technology of PIV in Dynamic Centrifugal Test and Design Method of Instrumentation
Authors: Wang Yong Zhi , Yuan Xiao Ming
Published: April 2014

PIV is a velocity-measuring technology commonly applied for the measurement of deformation and displacement in the field of experimental fluid mechanics, but no previous report is found for the application of this technology in dynamic centrifugal tests. As soil is a type of complicated materials with mechanical properties closely tying with the stress condition it suffered, centrifugal shaker shows great superiority to the research of soil dynamics and geotechnical earthquake engineering. PIV capable of measuring deformation and displacement of any point at any time supplies overall visible information for full understanding of failure mechanism. For only the deformation of selected points captured by transducers in current instrumentation, the application of PIV in dynamic centrifugal tests is advantageous to understand the complex behavior of soil under earthquake and high-stress loading. This paper analyses the critical technology of PIV application in dynamic centrifugal tests and proposes the requirements of image acquisition system design as well as a method, which provide some guidance and reference for construction of centrifugal shaker.
Detection of Unfavorable Karst Cavities in the Carbonaceous Bedrock Area at the Kaihua Segment of Hangzhou-Xinanjiang-Jingdezhen Expressway
Authors: Xu Man , Chen Zhi Hua , Zeng Bin , Ye Wang Li , Chen Kai Fu
Published: April 2014

The karst cavities can cause great harm to the construction or running of expressway. During the construction of expressway, the detection of these unfavorable geological objects is usually by use of high density resistivity method, and the physical background of the method is the combination of high resistivity of bedrock and low resistivity of karst cavities. In the study area, the Kaihua segment of Hangzhou-Xinanjiang-Jingdezhen Expressway, the widely distributed rich carbonaceous bedrock shows low resistivity, and the conventional interpretation idea of high density resistivity method is not applicable. The research results of this paper suggest that the U shape of relative high resistivity can be an indicative for detection of unfavorable geological objects such as karst cavities. 6 out of 11 boreholes drilled for purpose of calibration revealed karst cavities, and the karst ratio is from 1.2% to 10.3%, indicating the new interpretation method is feasible and reliable.
Research on the Environmental Effects of GB-SAR for Dam Monitoring
Authors: Xing Cheng , Huang Jing Jing , Han Xian Quan
Published: April 2014

The all-weather, non-contact and high-accuracy deformation monitoring can be realized by using the GB-SAR system, which includes three key technologies such as Stepped Frequency Continuous Wave (SF-CW), synthetic aperture radar (SAR) and interferometry. In this paper, a deformation monitoring experiment made at Geheyan Dam is described. The effects on the monitoring data caused by atmospheric changes are analyzed, and the monitoring results are statistically analyzed. The results show that the deformation information of the entire dam surface can be reflected accurately with the monitoring data corrected by the environmental correction methods, and these corrected data can be used for analyzing the stability of the dam.
Experimental Investigation on Shear-Reinforced Masonry Sample with FRP Bars
Authors: Boscato Giosuè
Published: April 2014

The paper presents some considerations on the experimental tests already carried out on a kind of shear reinforcement of masonry not yet still employed. Indeed that is the use of FRP (fibre reinforced polymer) mesh rebar externally connected to the masonry samples through steel joints to improve their shear performances. The study try to learn final information about the design with this kind of shear reinforcement optimizing the very large experimental investigation on masonry sample subjected to shear diagonal test
Model's Calibration for Masonry Reinforced with FRP Mesh-Bars
Authors: Dal Cin Alessandra
Published: April 2014

The paper presents some considerations on the reliability of the available formulas to determine the shear strength of masonry reinforced with FRP (fibre reinforced polymer) material. In detail the outcomes of a model related to the Eurocode 6 is prepared in presence of not usual shear reinforcement as FRP mesh bars jointed to ten surface masonry through steel joints. The model considers the basic contribution due to the masonry material and then add the contribution related to the presence of a material as carbon bars that is characterized by higher behaviour in term of stiffness.
Simulation on Strengthening of a Cement Fresh Material Silo
Authors: Chen Yue Shun , Liu Li , Lei Xia Lin
Published: April 2014

For the lack of concrete strength, the outer wall of a cement fresh material silo cracking. Then the cracking structure members have been strengthened with externally bonded steel plates. The finite analysis software ABAQUS has been used to simulate the reinforced silo and the structural analysis software MORGAIN has been used to calculate the reinforcements in this paper. The simulation results show that, the bearing capacity of the silo has been improved with this strengthening method effectively. On the other hand it could be referenced to solve the problems of similar projects.
Damage Identification Based on Power Spectral Density Sensitivity Analysis of Structural Responses
Authors: Chen Wei Huan , Ding Chang Ying , He Bing Quan , Lv Zhong Rong , Liu Ji Ke
Published: April 2014

A new method is proposed to identify structural damages based on the power spectral density sensitivity analysis. The responses of the structure under stationary and random excitations are obtained using pseudo excitation method, and then the sensitivities of power spectral density with respect to the structural damage parameters are obtained similarly. Finite element model updating method is adopted to identify the structural damages. A numerical example of a shearing structure demonstrates the satisfactory results obtained from the present method.
Application of Fuzzy Pattern Recognition in Spalling Risk Evaluation of Concrete Structures at High Temperature
Authors: Li Rong Tao
Published: April 2014

Spalling phenomenon in concrete exposed to high temperatures, e.g. during a fire, can seriously jeopardize the integrity of a whole structure. Spalling risk analysis and evaluation has become the hot topic of research on fire-resistance behavior of concrete structures at present. Based on fuzzy pattern recognition, a model for evaluating spalling risk of concrete structures at high temperature is established according to the factors influencing explosive spalling. The influential factor set is composed of strength, water/cement ratio, fibres content, curing humidity, load level, and heating rate, whose weights are determined by their relative importance. Good agreements between the results of spalling risk prediction and the fire test show the capability of the proposed model in assessing the spalling risk of concrete structures at high temperature, which will provide important reference for the fire resistance design of concrete structures.
Application of the Failure Assessment Method for Cracked Pipeline
Authors: Bai Yong Qiang , Lv Liang Hai , Wang Tong , Zhang Xiao Feng
Published: April 2014

A new failure assessment curve of pipeline containing crack is provided in this paper. The new failure assessment curve is based on the J integral calculation method of the effective remote stress, and it is as simple as the R6 option 2. The result of the new failure assessment curve is as accurate as the result of the curve based on strict J integral. Moreover, the new failure assessment curve could be used for any stress-strain relationship material, including Ramborg-Osgood (R-O) material and non-R-O materials under monotonic increasing loading, such as long plastic yield plateau steel. The new failure assessment curve is applied to a case that came from the three pipes burst in a proof test of an oil pipeline. Comparison with the result in the proof test shows the result of the new failure curve presented in this paper is accurate.
The Influence of Main Components of Building under Residual Deformation in Subsidence Area
Authors: Yu Jian Bing
Published: April 2014

A proposed residential district intend to be built in some coal mine subsidence area . Surface deformation influence main components forces of the building is a complex change process. Using the finite element software ANSYS to analyse the main components of the proposed buildings. Analysing main components' internal force relatively change of the first floor under the surface deformation than without surfaced formation. The result reveal that under large surface deformation, the internal force of beam and column changed largely .Beam force increase significantly in excess of 100%, column force increased significantly in excess of 500%. Then analyse-1-3 layer component force changes largely. Residual deformation greatest impact is the underground floor and 1st floor, and then is 2 and 3layer. This study could provide certain design reference for using the subsidence area of Shanxi.
Explosion Experimental Study Based on the Small Tailings Pond Model
Authors: Lv Shu Ran , Wei Qing Nan , Yang Kai
Published: April 2014

Explosion experiment was implemented on the small tailings dam model, aims to study the explosion effect of tailings sand under the action of the explosion. Explosion experiment includes three phases; experimental points were set respectively in the starter dam, embankment and deposited beach. In this experiment, blasting vibration velocity and vertical displacement of sand body are measured and collected, so did the tailings sand’s moisture content, cracks’ size, blasting crater, water and sand spurt phenomenon. Experimental results show that the buried conditions and tailings dam’s moisture content have a significant impact on explosion effect. By processing the velocity and displacement data, the attenuation law of blast vibration velocity in the tailings dam is reached, the blasting vibration velocity corresponding to crack damage of sand body is predicted, and the relationship between failure phenomenon of the tailings dam and the displacement produced by explosion is obtained.
Modeling of Mechanical Damage in Traditional Brickwork Walls after Fire Exposure
Authors: Sciarretta Francesca
Published: April 2014

The paper addresses the issues of fire behavior of masonry walls made of traditional/historical component materials (bricks and mortar).There are reasons for coupling investigations on the residual mechanical properties to fire resistance data, aiming at a more complete knowledge of the behavior of a masonry member during and after fire exposure. The paper proposes a numerical approach via FEM to the problem of residual mechanical performance of load-bearing fire-separating masonry walls after insulation failure. The goal is to establish relationships between fire resistance ratings under exposure and decay in mechanical properties after exposure; the parameter of wall thickness is especially investigated. This is performed by means of FEM analysis, simulating a standard ISO 834 fire resistance test followed by a mechanical compressive failure test on each investigated type of wall. First, a preliminary transient heat flow analysis gives a numerical prediction of fire resistance after violation of I (Insulation) criterion; then, a staggered heat flow - stress analysis repeats the heating of the wall up to insulation failure and calculates the thermal strain accounting for cracking; finally, a 'cold' structural analysis in compression is performed on the thermally-deformed model after cooling. The comparison of numerical outcomes to available experimental information allows to judge the reliability of the numerical approach in reproducing the residual behavior of a masonry wall after fire exposure.
Effect of Wheel Pressure on Vibration of Straddle Monorail Transit Vehicle-Bridge System
Authors: Liu Guo , Jang Bo , Zhou Zhi Hui , Zeng Qing Yuan
Published: April 2014

The monorail beam (Z206-25) of Chongqing straddle monorail transit system was selected as the research object. The spatial coupling vibration model of vehicle-bridge system was established and corresponding procedure was compiled. The effect of travelling, steering and stabilizing wheel pressure respectively and typical combined wheel pressure on the system vibration was studied. The results show that the change of wheel pressure has great effect on the response of the system. The vertical response value increases with travelling wheel pressure increasing. The lateral response value increases with steering wheel pressure increasing, while the effect of stabilizing wheel pressure on the response is irregular. The effect of steering wheel pressure is greater than that of stabilizing wheel pressure on lateral responses. The effect of all of travelling and steering wheel pressure is greater than that of unilateral wheel pressure on the response. The effect tendency of stabilizing wheel pressure on the response is opposite to that of unilateral wheel pressure.
Estimation Method for Prestress Loss of Externally Prestressed Composite Girder Bridges
Authors: Zhao Yong Ming , Li Hong Xue , Wang Xue Wei
Published: April 2014

To accurately calculate the prestress of externally prestressed composite girder bridges, the six critical factors (the prestressing tendon withdrawal and anchor deformation, friction between prestressing tendon and deviator, prestressing tendon relaxation, concrete creep, concrete shrinkage and temperature changes) that cause the prestress loss of such type of the bridges are summarized and the corresponding simplified calculation methods are respectively derived on the basis of the existing researches. The prestressing tendons ability has an important influence on the mechanical behavior of prestressed composite girder bridges, which is the key design parameters. Prestress loss will occur in the process of long-term use, so that the whole beam stress redistribution occurs. How to accurately calculate the value of the prestressing loss is an issue of great concern to engineers. And at present there is few research for prestressed composite girder bridges. On the basis of existing research, this paper summarizes the key factors that lead to loss of prestress and derives the corresponding simplified calculation method for design reference.
Finite Element Simulation of Large Segment Hoisting Construction for Hong Kong-Zhuhai-Macao Bridge
Authors: Li Hong Xue , Duan Lun Liang , Wang Xue Wei , Zhu Bing
Published: April 2014

In the construction process of Hong Kong-Zhuhai-Macao Bridge, the side span girder of Qingzhou channel bridge, the non-navigable span of the shallow water region and the side span S11 ~ S17 large segments are located between transitional pier and auxiliary pier of Jiuzhou channel bridge are based on the large segment hoisting construction technique. The widely use of the large segment hoisting construction which can ensure the construction safety and shorten the construction period obviously, effectively reduce the bad environment factors in construction. All of these are important to the transportation hub, Hong Kong-Zhuhai-Macao Bridge. But because of the transformation of structural system and the complex stress of the large segment girder in the lifting point in transportation and hoisting process, it is significant to do the finite element simulation analysis.
Influence of Tensioning Stress to Web Cracking of Rigid Frame Bridge in Cantilever Construction
Authors: Yin Dong Jia , He Xiong Jun , You De Quan , Liu Bing Kai
Published: April 2014

Cantilever construction is main mode for prestressed concrete continuous rigid frame box-girder bridges, but the diagonal cracks on web are often appeared in construction. The prestressed tension is an important part of the construction beyond doubt. This article takes a bridge under construction as the background to analyze the variation of stressed in the process of construction by MIDAS FEA. The result shows that the vertical steel stretch-drawn in advance has to be a consensus in future.
Risk Prevention Measures for Three-Tower and Four-Span Suspension Bridge under Vehicle Fire
Authors: Liu Mu Yu , Tian Wei , Wang Ying , Jing Wu , Chen Xi
Published: April 2014

Risk prevention measures were put forward about vehicle burning in operating periods for three-tower and four-span suspension bridge, combining with the characteristics of bridge vehicle burning accident. The article set up a traffic reporting system of the tankers for a bridge, and determined the report system of tankers across the bridge. Tankers should passed in the middle of the lane near the median under the guidance of bridge manager. Significant indicators were set on both ends of the bridge, so that vehicles could shunt rapidly in extreme fire conditions. Department of public security, fire control, transportation, bridges management center should get together to establish accident emergency rescue leading group, and formulated the security system of fire resistance and rescue organization for YingWuzhou Yangtze river bridge. Video monitoring alarm system and fire control facilities were set up in side pier, side tower, middle of the main span and the middle tower, which provided reliable and prevention measures for bridge operation.
Study on Nonlinear Structural Behaviors of Steel and Concrete Composite Slab
Authors: Xu Shuo , Xiang Tian Yu
Published: April 2014

Steel and concrete composite slab is a new type of bridge deck, which is consist of steel plate and concrete slab connected by shear connectors such as perfobond ribs ( usually abbreviated as PBL), studs and so on. Static experiment about four pieces of one-way steel and concrete composite slab using PBL was carried, and the whole-process structural behaviors and failure mode were investigated. Based on the spatial beam element model with the degenerated theory, the nonlinear finite element analysis on experimental specimens was executed. Such structural behaviors as concrete cracking, yield of steel plate, crushing of concrete, and so on are simulated, and are compared with the experimental results. It can be observed that excellent agreements are achieved between experimental results and numerical simulation.
The Local Stress Analysis of Slide Beam Taking into Account the Roughness of Girder Undersurface
Authors: Wang Yong Bao , Li Zhao Yu , Zhao Ren Da
Published: April 2014

The bridge incremental launching method has been widely used in China nowadays. As one of the key parts in the incremental launching process, traditional calculation methods cannot meet the current accurate demand of stress state for slide beam. With the assistance of finite element software ANSYS and harmonic superposition method, this paper respectively analyzes the local stress state and the overall buckling of roof, web as well as diaphragm of the slide beam by adding the roughness influence of girder undersurface.
Bridge Pavla Wonky in Pardubice. Diagnostics of Corrosion Condition of External Cables and Use of Special Materials for Proposal of Treatment
Authors: Kolísko Jiri , Huňka Petr , Rehacek Stanislav
Published: April 2014

Annotation: Complete reconstruction of the reinforced prestressed bridge Pavla Wonky in Pardubice was carried out in 2006. During this reconstruction specialists of the Klokner's Institute made complete revision of linear free external cables in bridge chambers, namely from the aspect of corrosion. Some of the findings obtained during this revision are presented in this article.
Analysis on the Influence of the Primary Consolidation Settlement of the e~p Curves and the Soil Bulk Density of the Soft Soil Foundation
Authors: Wang Wen Shuang , Yu Jiong Qi
Published: April 2014

In general, primary consolidation settlement of soft foundation is calculated by layerwise summation method considering the design load in seawall engineering design, and the total settlement is obtained by multiplying a settlement correction coefficient which is difficult to select. In this paper, one seawall engineering case is enumerated, the impact on the thickness of compressible stratum and the primary consolidation settlement is studied by considering the changes of the e~p curves of the soft soil foundation. The results indicate that the thickness of the compressible stratum changes obviously for different stress ratio owing to the difference of the soil bulk density of the compressible soil, and the primary consolidation settlement has corresponding change tendency according to the shape of the e ~ p curves and the soil bulk density of the compressed soil. At last, this paper suggests that a designer can weaken the weight of settlement correction coefficient based on the analysis of the influence of primary consolidation settlement with different e ~ p curves of the soft soil foundation in future design.
Characteristics of Xinjiang Bad Foundation Soil
Authors: Zhang Ju Hong
Published: April 2014

Safety Engineering geological conditions and the building has a correct evaluation of soil close relationship, poor soil and treatment is essential in terms of building security. This article describes the main types and characteristics of Xinjiang poor soil, and through practical case describes the characteristics and saline land-based treatment program.
Numerical Analysis of the Excavation of Deep Pit Based on Mohr-Coulomb Failure Model
Authors: Sun Hai Jian , Li Yong Quan
Published: April 2014

The Principles of Mohr-Coulomb failure model and hardening and rate dependence are dealt with in detail. Based on Mohr-Coulomb failure model with isotropic hardening, numerical analysis is conducted . The results calculated show that the horizontal displacement and moment of the continuous wall, and the subsidence of surface outside the pit agree with the objective laws during the excavation. The method adopted and those results gained by numerical method may provide reference to engineering practice.
A Study on the Effect of a Dyke Reinforced by Geotextile-Encased Sand Columns
Authors: Ouyang Fang , Bi Jun Wei , Han Jian Wei , Liao Wei Ming
Published: April 2014

A dyke construction was dealed with geotextile-encased sand columns. The dyke was used to enclose a polder in Hamburg-Finkenwerder, Germany. With the help of geotextile, the columns can be used in very soft soils , even undrained shear strength cu < 15 kN/m2, without excessive bulging. After the system is installed, the dike can be filled immediately. To analysis observed data of the long-term settlements in the dyke, three stages can be gotten i.e. "Primary settlements" - "Secondary settlements" - "Creep settlements". Most settlements occurred during the primary filling, while, only little settlements appeared after that construction was accomplished. The settlement rate decreases from the first settlement stage to the last one. No jump takes place when unloading soft soil. Furthermore, the method shorten time and saved a lot of money.
On Atypical Affection on Environment due to Dewatering of Foundation Pit in Developed River System Area
Authors: Li Dan , Li Nian Feng , Tang Bin , Gong Jian Wu
Published: April 2014

With the environment problems more and more emerged the matters caused by dewatering are set out to be probed and the rule that the ground settlement around a dewatering well presents a funnel shape , is acquainted usually. But in the case of special geology and hydrology due to this paper a new ground settlement pattern presents according to the buildings failure status and the subsequently monitoring results analysis. Namely the ground settlement along the transverse direction to the underground runoff presents V-shape flute profile in the area around the predominant underground runoff. The results also demonstrate that: 1 The foundation type in main building is as same as in the podium building .The main building kept stable while the podium building presented large settlement and inclination and went to failure in final during the construction of the pit. 2 The difference of affecting degree due to dewatering in the environment around the pit is variable and the main affecting zone appears locality and directivity. According to the investigation the most possible main resource of dewatering originates from the river system around to the pit pass by the podium building. 3 Combining the construction process of the pit and the time points of deformation in the building , associability is confirmed between buildings deformation and dewatering on the pit on the ground of excluding the other artificial factors around the building.
Stability Analysis of Surrounding Rock with Two Groups Parallel Joints Using DDARF Method
Authors: Ma Hai Ping , Wang Li Ge , Li Xue Wei
Published: April 2014

In order to analyze the stability of surrounding rocks with two groups parallel joints under different angles, a new method, DDARF (discontinuous deformation analysis for rock failure) program was adopted to investigate three cases of uniaxial compression tests of two groups parallel joints sample with the angels 30, 45 and 60. The results show the sample with 30 is least prone to be destroyed and the sample with 60 are most likely to be destroyed. Then DDARF program was also applied to investigate the underground cavern excavation process of two groups parallel joints surrounding rocks with the angels 30, 45 and 60. The results show that the stability of underground cavern with joint angel of 60 is worst in the aspect of stability.
Study of Reasonable Length of Coal Seam Mining under Different Fault Dips
Authors: Zhang Yun Jie , Xu Tao
Published: April 2014

In this paper, the stress and strain distribution in coal seam and fault edge under various fault dips is numerically simulated to study the stability of the barrier pillar and determine the reasonable length of coal seam mining using COMSOL Multiphysics package. Numerical simulations show that remarkable increase in stress around fault edge when coal seam is about 250 m away from the fault with a smaller fault angle and the stability of fault is seriously affected by the mining excavation. While the obvious increase in stress around fault edge can be observed until coal seam is about 200 m or 150 m away from the fault with a larger fault angle and the stability of fault is seriously affected by mining excavation. Numerical results indicate that the larger the fault dip is, the larger the reasonable mining length in coal seam where a fault near coal seam exists. Moreover, the fault with smaller dip is more easily activated to induce the failure of the fault and the occurrence of water inrush in coal mining. To prevent the occurrence of fault failure accident, we need to study the reasonable mining length of coal seam, to ensure the safety production and increase the recovery ratio of coal.
Study of Reinforcement Scheme for Tunnel Heaving due to Excavation of Sunken Plaza over Subway Tunnels
Authors: Lin Hong , Yang Jiang , Chen Jing Tao , Luo Qing Quan
Published: April 2014

The excavation of large area close to the top of the tunnel, is likely to lead to a big displacement and deformation of the tunnel, even endanger the safety of subways operation. Therefore, it has become a problem urgently to be solved that how to accurately predict and reduce the deformation of subway tunnel caused by excavation of sunken plaza. Build a numerical model in the finite difference software FLAC 3D, then according to the order of the construction organization, calculation and analysis four different reinforcement schemes in the process of the excavation of sunken plaza, the reinforcement schemes are Without reinforcement measures, adopt gantry soil-cement mixing pile reinforcement scheme, sinking square are at the bottom of the uplift pile reinforcement scheme and comprehensive use of soil-cement mixing pile of door and sinking square with uplift pile reinforcement scheme, then comparison and evaluation the effects of the four kinds of reinforcement schemes around the selected four indicators, they are the maximum vertical settlement of the tunnel, the maximum horizontal displacement value of the tunnel, the maximum convergence of a tunnel diameter and the minimum radius of curvature tunnel deformation curve .From the analysis, some conclusions can be drawn.
Study on Effect of Excavation Depth on Internal Force of Retaining Structure of Arc Row Piles with Arc Ring Beam on the Pile Top
Authors: Zhang Zhi Wei , Deng Rong Gui , Chen Ze Shuo
Published: April 2014

In order to control deformation of foundation pit effectively and guarantee safety of building around, utilizing the stress characteristics of arch, use the new spatial retaining structure of arc row piles with arc ring beam on the pile top. The arc ring beam can provide constraint to pile top, so internal force of pile body distribution is uniform, and improve the integrity stability of piles. The ring beam with compression mainly can give use of high compression capability of concrete. According to the high order statically indeterminate characteristics of the retaining structure, calculation model of ring beam and pile respectively is established by the redundant forces between beam and pile top. By using deformation compatibility to set up flexibility equation of the retaining structure, and solve the redundant forces, then calculate the internal force and displacement of ring beam and piles. Through calculating the practical engineering, research the effect of excavation depth on internal force and displacement of piles and the arc ring beam on the pile top.
Study on Expansion Properties Experimental of the Different Stratification Slates in Chongqing
Authors: Zhang Yun Jie , Fan Cheng
Published: April 2014

In order to study the expansion properties of slates, this paper tests multiple groups of data, including free expansion ratio, expansion force and expansion strain for the different stratification slates in Chongqing. We found that with the increase of time, the axial expansion ratio and swelling pressure of different stratification slates begin to increase rapidly in the initial period,until gradually moving to a maximum value.In addition, slates stratification in different directions has different expansion properties, the perpendicular to stratification direction has greater expansion ratio, is about 2.5 times more than the expansion ratio of parallel to the bedding. In the constrained conditions, axial expansion ratio of the slates is much larger than that without constraints. Different stratification of expansion pressure and the expansion strain of the slates is linear in the volume remains unchanged. This research project has certain reference value for the civil engineering on the different stratification slates expansion construction in Chongqing.
Study on the Interfacial Shear Stress Distribution Characteristics of Geotechnical Prestressed Anchorage Structure
Authors: Zhang Si Feng , Zhang Long , Li Lin , Song Xiu Guang
Published: April 2014

The ultimate bearing capacity of prestressed anchorage structure is directly related to the interfacial shear stress distribution characteristics of the inner anchorage section. Firstly, the axial stress distribution characteristics of the inner anchorage section for the geotechnical prestressed anchorage structure under tensile load are further studied by indoor similarity model test, and the corresponding fitting formula is established. Based on this result and the force equilibrium conditions of rod body’s micro-segment, the rod body interfacial shear stress distribution characteristics formula is also derived, which fits well with the results of the indoor model test. The research achievements have important significance for the further study on stress distribution characteristics of the inner anchorage section.
The Preliminary Study on the Impact of the Velocity Situ Test Standard Deviation to the Response Spectra in Deep-Soft Sites
Authors: Chen Zhuo Shi , Yuan Xiao Ming , Meng Shang Jiu
Published: April 2014

The test results of shear-wave velocity in engineering are of being importance increasingly, but the the uncertainty of the wave test result has influenced the seismic design throughout. In order to describe this uncertainty accurately , the paper has taken some research on the deep-soft sites seismic response. By using SHAKE 2000 program and entering various types of ground motions, the authors discussed the effect of shear-wave velocity standard deviation of several velocity values in deep-soft site to the ground response spectra and PGA(Peak Ground Acceleration). The results are as followed: the standard deviation of the shear-wave velocities has almost no influence on the acceleration response spectra and the PGA of the site; the varieties of response spectra and PGA under different intensity of earthquake can be nearly ignored. With the increasing number of the shear-wave velocity data, results of the study would be further in-depth and perfection.