bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Mixture Proportion Optimization and Crack Resistance of Concrete of Three Gorges Dam
Authors: Sun Kai Chang , Sun Zhi Yu
Published: December 2010

The optimization of mixture proportion is determined by intensive tests based on designed index of the concrete in Three Gorges Dam. It is proved that the crack resistance of the concrete of the Dam is excellent by experiments and investigated results on site. The concrete is designed in a new method which is translated from traditional strength design into durability design. The effective additive and fly ash and moderate heat cement with micro-expansion are applied widely which enhance the capabilities of concrete essentially. So the long-term durability of the concrete in Three Gorges Project is ensured.
Study on the Numerical Modeling of the SRHPC Frame
Authors: Hou Pi Ji , Zheng Shan Suo , Li Lei
Published: December 2010

The modeling methodology is investigated for steel reinforced high performance concrete (SRHPC) in this paper. According to the mechanical characteristics of the SRHPC members, the structural section can be divided into different zones, and the element suitable for each zone is determined. Some discussion is made for how to control finite element gridding as well as applied load. Hysteretic loops of the computation results and test results agree well with each other, indicating the accuracy and applicability of the methodology. This research may be helpful for the nonlinear finite analysis of the SRHPC frame structure.
Pure Shear Capacity Analysis on Square Tube Filled with Steel Reinforced Concrete
Authors: Ou Yang Wei , Zhao Tong Feng , Zhen Xiao Dong
Published: December 2010

Square steel tube filled with steel reinforced concrete subjected to shear force was simulated by finite element method. Limit value of broken on pure shear, bending-shear and bending were given. Influence of stirrup ratio, steel reinforced ratio, strength of concrete under shear force was also analyzed. Finally, formula for pure shear capacity of square steel tube filled with steel reinforced concrete was proposed by research the calculated results. Calculated results showed that it agreed well with that of corresponding document.
Structural Configurations and Economic Performance Comparison of Multi-Storey and High-Rise Steel Three-Dimensional Garages
Authors: He Yong Jun , Zhou Xu Hong , Hu Jun Cheng
Published: December 2010

Development of multi-story and high-rise steel three-dimensional (3D) garages is an effective way to solve the parking problem in modern cities. In this paper, several types of multi-story and high-rise steel 3D garages are presented. The structural configurations and design parameters of the 3D garages, such as structural planar layout, storey height and limit value of horizontal displacement, are analyzed. Then the economic performances of the steel 3D garages are compared and their suitable storey numbers are obtained.
Effects of Steel Slag Powder on Performance of Concrete
Authors: Zhang Jin Xia , Liu Shu Xian , Niu Fu Sheng , Nie Yi Miao
Published: December 2010

Slump and compressive strength of the concrete with different steel slag powder content and different finenesses were discussed in this paper. It was indicated that: 1) High performance concrete with higher strength can be made using ground steel slag powder. 2) The greater content of steel slag powder, the more obvious was the effect of reducing slump losing. 3) About 40MPa concrete can be made using the steel slag powder whose specific surface was 510~600m2/kg under the condition that the content of steel slag powder was 50%~60%. 4) When the content of steel slag to be certain, the finenesses of steel slag powder had little effect on the performance of concrete.
Fire Experimental Study of Four-Edge Fixed Reinforced Concrete Slab in Fire
Authors: Wang Bin , Dong Yu Li , Gao Li Tang
Published: December 2010

The performance of one full scale four- edge fixed reinforced concrete slab under the condition of combined effects of loading and fire was investigated. The specimens design, the test plan, the test contents and the test methods were firstly introduced. Through the experiments, the distribution of temperature field along the depth of the slab and the temperature changes of the inner steel were obtained, as well as the deformation of out-plane and in-plane and the rotation on the edges. The changing of reaction forces on the bearings of the slab with the temperature was also observed. The results indicated that, under the condition of fire, the out-plan deformation of the slab was much bigger than that of the normal temperature; non-linear temperature filed was existed along the depth of the slab; remarkable redistribution of the reaction forces were occurred on the fixed bearings. The fail pattern of the slab under the condition of combined effects of loading and fire was different from the static loading under normal temperature. The slab was suffered reverse forces because of the heat effects; hence the plastic hinge lines with the shape of elliptic basin were appeared on the top of the slab.
Finite Element Analysis on Twin Tower Building with Large Bases Subjected to Seismic Action
Authors: Qian Shan Guang , Li Yun , Song Juan
Published: December 2010

In this paper, twin tower buildings with large bases were studied. The FEM models with connecting and without connecting buildings were established separately. The dynamic characteristics of both models were studied. The influences of connection over the structure vibration mode and natural vibration period were discussed. The dynamic responses of models were also analyzed by time-domain buffeting analysis method. The influences of the connection over the top of the structure’s lateral displacements, and acceleration and the bottom of the structure’s overall shear forces were discussed also. The conclusion of this paper may provide scientific basis to the structure design.
Seismic Response of Cable Net Facade
Authors: Feng Ruo Qiang , Ye Ji Hong , Wu Yue , Shen Shi Zhao
Published: December 2010

Shaking table tests and theoretical analysis were conducted to study of the seismic response of cable net facade. Firstly dynamic response of cable net façade under earthquake was investigated with shaking table test. Then a numerical simulation model of cable net façade was built for the dynamic analysis .And then with this model the seismic response was analyzed theoretically. The study indicates that: the seismic response of the cable net with glass panels and the cable net on most occasions are mainly decided by the symmetric modes, and the first vibration mode is dominant. The damping of cable net facade is mainly decided by glass panels.
Performance Deterioration of High Strength Concrete under Mixed Erosion and Freeze-Thaw Cycling
Authors: Zhang Jian , Diao Bo , Zheng Xiao Ning , Li Yan Dong
Published: December 2010

The mechanical properties of high strength concrete(HSC) were experimentally investigated under mixed erosion and freeze-thaw cycling according to ASTM C666(Procedure B), the erosion solution was mixed by weight of 3% sodium chloride and 5% sodium sulfate. The mass loss, relative dynamic modulus of elasticity, compressive strength, elastic modulus and other relative data were measured. The results showed that with the increasing number of freeze-thaw cycles, the surface scaled more seriously; the mass loss, compressive strength and elastic modulus continued to decrease; the relative dynamic modulus of elasticity increased slightly in the first 225 freeze-thaw cycles, then decreased in the following 75 cycles; the corresponding strain to peak stress decreased with the increase of freeze-thaw cycles. After 200 cycles, the rate of deterioration of concrete accelerated obviously.
Application of Polypropylene Fiber Concrete in Underground Engineering
Authors: Shao Xiao Rong , Zhu Liang Feng
Published: December 2010

Aimed to solve the problem that the mass concrete structures are apt to crack in underground engineering, this paper makes some research from the view of crack resistance performance of polypropylene fiber concretes. Since polypropylene fiber achieves waterproof through realizing of crack resistant, blending polypropylene fibers into concretes can reduce early contraction deformation of concretes, hinder emergence of plastic shrinkage cracking and improve impermeability of concretes, and its construction technology is simple. In practical application of this in anti-cracking and anti- seepage concrete structures in the International Terminal project of Hangzhou Xiaoshan International Airport, we find that mix of polypropylene fibers with concretes clearly improves anti-cracking and anti-seepage performance of concrete structures and meets design requirements of basements through measuring temperature and observing cracking condition of the mass concrete structures of basements on site. The project can provide experience for reference to similar projects.
Dynamic Load-Displacement Behavior of Rc Shear Walls under Different Loading Rates: Tests and Simulations
Authors: Xu Ning , Xu Bin , Zeng Xiang , Jiang Zhou , Chen Jun Ming
Published: December 2010

As a typical structural member, the dynamic behavior of RC shear walls under seismic dynamic loads and/or strong winds is a critical topic. In recent years, with the development of test facilities and numeric techniques, efforts have been made to study the dynamic behavior of RC shear walls under dynamic loadings experimentally and numerically. But available test results on the dynamic behavior of RC shear walls are limited because of the limitation of the large-scale test facilities for dynamic tests. In this paper, test on four RC shear walls under rapid loads are conducted and a finite element model of RC shear walls through introducing the strain rate effect to the concrete damaged plasticity model in ABAQUS is established to simulate the dynamic behavior of the four specimens tested. Through comparing the simulation result with the test result, it is clear that the developed dynamic damage plastic constitutive model of concrete can be employed to simulate the nonlinear behavior of RC walls with acceptable accuracy under dynamic load.
Study on Temperature Distribution Characteristic of Asphalt Mixtures of Bridge Deck
Authors: You Qing Long , Zheng Nan Xiang , Shi Gang Lei
Published: December 2010

Flexible pavements comprise a majority part of highways in china. Many highway bridges are constructed in these highways. These primary highway bridges are subjected to the same heavy loading as the conventional asphalt pavement, but caused much more significant damage than the conventional asphalt pavement. As hot-mix asphalt (HMA) is a visco-elastic material and the all around environment is different between road pavement and bridge deck, the structural or load-carrying capacity of road pavement and bridge deck is different. Thus, to accurately determine in situ strength characteristics of flexible pavement, it is necessary to predict the temperature distribution within the HMA layers and find the difference between road pavement and bridge deck. The majority of previously published research concentrated on pavement temperature prediction. To confirm the bridge deck temperature profile, observing the temperature at bridge deck and road pavement for two months. Compared with the temperature profile of bridge deck and road pavement, find the difference between them. Then some daily temperature prediction models are analyzed and develop a modified double-sine model to simulate the surface temperature variation of bridge deck.
An Industrialized Multi-Layer Precast Concrete Frame Building with Middle-Joint Beams and Columns
Authors: Xu Ying , Dong Bi Qin
Published: December 2010

An industrialized multi-layer precast concrete building with middle-joint beams and columns frame system has been developed by China VANKE CO., LTD. The building is the first industrialized multi-layer precast concrete building for experimental purpose in China. A middle-joint beams and columns method has been utilized with beams and columns split in the middle place. The whole frame structure is then integrated into a unity through precast beams, precast columns, and reliable cast-in-place column-column and beam-beam joints. This paper presents the key points and difficulties during the building design process, introduces the structural design of column-column and beam-beam joints, and analyses the advantages and weaknesses of middle-joint beams and columns frame system.
Prediction of Internal Stability for Geogrid-Reinforced Segmental Walls
Authors: Kasa Anuar , Chik Zamri , Mohd Raihan Taha
Published: December 2010

Prediction of internal stability for segmental retaining walls reinforced with geogrid and backfilled with residual soil was carried out using statistical methods and artificial neural networks (ANN). Prediction was based on data obtained from 234 segmental retaining wall designs using procedures developed by the National Concrete Masonry Association (NCMA). The study showed that prediction made using ANN was generally more accurate to the target compared with statistical methods using mathematical models of linear, pure quadratic, full quadratic and interactions.
The Technology of Asphalt Pavement on Wei He Steel Bridge Deck
Authors: Gui Xue , Wang Xiu Shan , Li Bao Yin
Published: December 2010

In connection with the more special paving conditions on deck pavement of Wei He (yellow river) Steel Bridge in Xi`an, various pavement plans have been analyzed by material test methods and mechanical simulation methods. Based on the research and construction of deck pavement in some built steel bridges, Combining our existing equipment and technology at asphalt concrete deck pavement, obtain better pavement performance program as a design. And introduced some issues to which should pay more attention in the implementation of critical control.
Preparation and Characteristic of PSMA/EG Composite Materials
Authors: Hou Gui Xiang , Na Hai Ning , Sang Xiao Ming
Published: December 2010

Graphite nanosheets prepared through high-temperature oxidation via powdering the expanded graphite. After soaking the expanded graphite with styrene(S) and maleic anhydride(MA) monomers, the polymer (Poly(S-co-MA))/expanded graphite(EG) (PSMA/EG) composite granules were obtained by in situ polymerization. Light microscope，scanning electron microscope and X-ray diffraction characterization were performed. SEM analysis indicate that the expanded graphite was mostly tore to sheets with thickness of 50–80 nm and with diameter of 1μm. Optical micrographs showed that the distribution of graphite platelets is found to be nearly uniform.
The Analysis for the Static Responses of the through Composite Truss Bridge with Simply Supportation
Authors: Chen Yu Ji , Luo Qi Zhi
Published: December 2010

According to deforming properties of the structure in the action of symmetry loads and the assumption to the displacement functions of the equivalent composite box beam, the total potential energy of the structure is obtained. Based on the spline finite point method, the stiffness equations are deduced, which could be used to determine the approximate solution of the through composite truss under the action of double-lines symmetry loads in considering the relative slip between longitudinal beams and concrete slabs on the deck system, the vertical deformation of transverse beams and the shear lag effect of concrete slabs. The mechanics behavior of the thorough composite truss is studied by means of a calculated example.
Study on Stud Shear Connectors Subjected to Single Cyclic Loading
Authors: Li Xiang Jie , Mu Zai Gen , Li Ping An , Zhang Ju Bing
Published: December 2010

In order to study the behavior of connectors used in steel-concrete composite beam subjected to single cyclic loading, three groups of studs were tested with new specimen and new method, stud’s diameter is different among each group(Φ16,Φ19,Φ22). Stud’s fatigue behavior subjected to single cyclic loading various with the diameter.
Nonlinear Stability Bearing Capacity Analysis for Plate-Cone Reticulated Shell
Authors: Wang Fan , Wang Xing
Published: December 2010

Plate-cone reticulated shell is a new type of double-layer reticulated shell in which ventral members is replaced by cone elements. This paper carries out nonlinear stability bearing capacity analysis on plate-cone reticulated shell considering geometrical nonlinearity of cooperating work between plates and members. In this paper, stability bearing capacity of plate-cone reticulated shells with different kinds of structure form considering geometrical nonlinearity is analyzed by using the software ANSYS, tracking complete process balance path for load-displacement by using arc-length method, the several problems of plate-cone reticulated shell are studied, such as destruction mechanism, structural ductility, stability ultimate bearing capacity and strength reserve, some important conclusions are obtained. After analyzing the stability behavior of double-layer reticulated shell by ANSYS and comparing with plate-cone reticulated shell, it is proved that plate-cone reticulated shell is more advantageous than double-layer reticulated shell in the aspect of stability bearing capacity behavior.
Analysis of Structural Parameters of Cable-Stayed Suspension Bridges
Authors: Qiu Jing , Shen Rui Li , Li Huai Guang , Zhang Xun
Published: December 2010

The cable-stayed suspension bridge is a novel composite structure with great overall stiffness and the capacity to span a long distance, which has been proposed for the design of some extra long-span bridges. To take further research on mechanical properties and behavior of this type of structure, the proposed preliminary design of a cable-stayed suspension bridge with a main span of 1800m is analyzed. The three-dimensional nonlinear analysis method is used to investigate systematically the influence of various principal structural parameters on the static and dynamic behavior of bridges. These parameters include the rise-span ratio, the suspension-to-span ratio, the constraint condition of the stiffened girder, the number of auxiliary piers at side spans, the layout of suspension cables, and the elastic modulus of suspension cables. Meanwhile, the selection of the rational values of these parameters is discussed.
A Discussion on some Key Issues for Seismic Design of Concentrically Braced Frames According to Canadian and Chinese Codes
Authors: Zhang Wen Yuan , Christopoulos Constantin
Published: December 2010

To gain further insight into the seismic design of concentrically braced frames as defined by the Canadian and Chinese codes, a comparison of the main design requirements contained in each code is carried out in this paper. The comparison emphasizes on the differences existing in these two code provisions, and the reasons behind them. The issues that are examined include the seismic force resisting systems for braced frames, the height restrictions, the force transferred to the beams in chevron configurations, the slenderness ratios of the bracing members, the width-to-thickness ratios of the brace sections, and the influence of brace connections on the columns. Some additional issues that still remain undefined on the seismic response of these systems and some proposals for further studies are also discussed. It is concluded through this comparison that a number of modifications are still required in order to fully implement a capacity design approach of these systems in both codes.
Experimental Research on the Confinement Effect for the Composite Concrete-Filled Square Steel Tubular Short Columns
Authors: Li Bin , Gao Chun Yan
Published: December 2010

Through the axial compression tests of two ordinary concrete-filled square steel tubular(CFSST) short columns and six composite CFSST short columns, the influence laws of section types, confinement coefficient, steel ratio and concrete strength on the mechanical behavior of the CFSST short columns were studied. The results show that in CFSST columns, the change of steel tube’s section form can improve effectively the cooperative work ability between the steel tube and core concrete, enhance the restraint effect of the steel tube on the core concrete, delay or inhibit the development of inclined cracks in the core concrete, increase the ductility and improve significantly the ultimate bearing capacity when the steel ratio or confinement coefficient is close to each other. With the increment of the confinement coefficient and steel ratio, the bearing capacity and ductility improve.
Experimental Research on PBL Shear Connector for Steel-Concrete Composite Structures
Authors: Xiao Lin , Qiang Shi Zhong , Xu Xun
Published: December 2010

PBL shear connector is a recently developed shear connector for steel-concrete composite structure that making the two element work as a unique piece. In this work, model test has been carried out to investigate the mechanical characteristics of 21 specimens in 7 types of PBL connectors. Combining the model test with finite element simulation, the main work has been done as follows：Load transfer behavior, load-slippage rule and static load mechanical property of PBL have been analyzed. Research on main factors that could influence the mechanical characteristic of PBL has also been conducted. Based on comparison of results of model test and finite element analysis, the feasibility of push-out simulation by nonlinear FEM has been analyzed. Compared to typical push-out tests results in mainland China, recommendations of push-out test of PBL are presented.
Time-History Analysis of Seismic Response for the Concrete-Filled Steel Tubular Wind Turbine Tower Based on Finite Element Method
Authors: Wen Yang , Zhou Fei
Published: December 2010

In the article based on the geometric characteristics of the tower and force characteristics, the author designs the concrete-filled steel tube (CFST) 3 limbs column tower, and establishes finite element model of the tower. We carry on time history analysis of the concrete-filled steel tubular wind turbine tower based on finite element method when the earthquake wave is different. Under rare earthquake, the majority bars of the concrete-filled steel tube 3 limbs column tower are in the elastic stage, only a small number of bars in the top and the bottom are into the plastic phase. The post-seismic displacement at the top of tower is 1.1m which is slightly less than the tower height of 1 / 50 (1.26m) and meets the seismic requirements of the region. The analytical result may provide the foundational test data and advice for the design of the CFST wind turbine tower.
Numerical Method and Experimental Study on the Ultimate Load Carrying Capacity of Four Tube CFST Latticed Columns
Authors: Jiang Li Zhong , Zhou Wang Bao , Qi Jing Jing
Published: December 2010

The paper presents a numerical method for calculating the load-deformation response and ultimate load carrying capacity of Concrete Filled Steel Tubular (CFST) latticed columns A half-wave sinusoidal function is assumed for the deflected shape of the column. The effect of confinement and shear deformation are included in the analysis, and the corresponding equilibrium equation is established. The method applies to eccentrically loaded compression members bent in single curvature. Unequal end eccentricities can be considered. Test results are reported for seventeen four latticed column specimens with varying end eccentricities and slenderness ratios. The obtained results show that eccentricity has significant effect on the bearing capacity of specimen, and the slenderness ratio also has some influence. The diagonal lacing bars remained in the elastic state during the entire load range. When specimens go into the nonlinear stage, Poisson's ratio of the near-load steel tube increases and a significant confinement effect can be observed. For the far-load steel tube, confinement effect does not occur to a significant extent. Specimen failure is due to overall instability except in the case of several individual short columns. Good agreement was found between the theoretical and experimental results using the numerical method developed in the paper. The proposed numerical method is shown to be more accurate than the current method presented in the Chinese code.
Behavior of Rigid Composite Joint under Combination of Bending Moment and Tensional Force
Authors: Guo Lan Hui , Gao Shan , Zhang Su Mei
Published: December 2010

In recent years, the progressive collapse of buildings increases the interest in progressive collapse studies. If a key column fails in structure, the internal force is redistributed by the catenary action of joint to prevent its progressive collapse. The joint connecting to the failed column is under the state of bending moment combined with tensional force and the tensional force would affect the moment-resistance ability and ductility of joint. In this paper, the finite element software ABAQUS is applied to analyze the behavior of composite joints under the state of bending moment combined with tensional force. The effects of rebar ratio, rebar strength, concrete strength, etc., on the behavior of joints are investigated. The results show that high strength steel is suggested to be used in composite joint to improve its bending moment capacity and tensional capacity.
Experimental Study on Seismic Performance of RC Composite Core Walls with Steel Tube-Reinforced Concrete Columns and Concealed Steel Trusses under Eccentric Horizontal Loading
Authors: Dong Hong Ying , Cao Wan Lin , Zhang Jian Wei
Published: December 2010

Two 1/6 scale core walls, including one RC core wall with steel tube-reinforced concrete columns and concealed steel trusses and one conventional RC core wall, were tested under eccentric horizontal cyclic loading. The load-capacity, ductility, hysteresis characteristics, stiffness, stiffness deterioration process, energy dissipation and damage characteristics of the two specimens were compared and discussed in this paper. It shows that the seismic performance of the RC core walls under combined action could be improved by setting the concealed steel trusses in the walls and using the steel tube-reinforced concrete columns as the boundary elements.
Study on the Vehicle-Bridge Coupling Vibration of Steel Arch Bridge
Authors: Li Zi Lin , Zhou Pei Yuan , Yun Zhen Bo
Published: December 2010

The modal analysis and the calculation of dynamic response of the Fenghua Bridge, a new type of long-span steel arch bridge, are carried out using the finite element software ANSYS. Through the on-site testing, the vibration frequency and the change of dynamic displacement response with different weight and speeds are obtained by the DASP data processing software. It is found that the field test results are in consistent with the theoretical results. Firstly, the natural vibration period is 2 ~ 3 times longer than the other ordinary arch bridges, which indicate the bridge structure is stable; Secondly, the dynamic displacement of bridge deck changes in the same direction with weight, while in the opposite direction with speed, and the maximum appears on the midpoint of the middle span; Finally, the maximum dynamic displacement is 11.41mm, which doesn’t exceed the allowable value. So it can be concluded that the bridge is safe under the vehicle-bridge coupling vibration.
Optimization on Closure Scheme of Multi-Span Prestressed Concrete Box-Girder Bridge
Authors: Yuan Ming , Yan Dong Huang
Published: December 2010

The stress state of finished bridge and service stage is influenced by various closure schemes in cantilever construction of multi-span prestressed concrete box-girder bridge. Two typical bridges—multi-span prestressed concrete continuous rigid frame bridge and girder bridge are investigated, The stress state in different closure schemes are analyzed using finite element(FE) analysis. Meanwhile, compared the healthy monitoring data, it has been found that taking the closure sequence from side span to middle span in cantilever construction of multi-span prestressed concrete box-girder bridge can lower stress of girder and pier in finished bridge stage, as well as reducing deformation of girder in service stage. Hence, the closure sequence from side span to middle span is more suitable for cantilever construction of multi-span prestressed concrete box-girder bridge.
A Simplified Seismic Design Method on Steel Truss Coupling Beam
Authors: Hu Qiang , Deng Zhi Heng , Pang Zhen Zhong , Lu He Yong
Published: December 2010

A simplified seismic design model on steel truss coupling beam is suggested based on compatible distortion and balance conditions, considering second order effect and perfect plasticity. This model regards web members of the coupling beam as constraints, thus just the chord need be studied instead of the whole truss. End moments and end shears of chords and relations between distortions of components of the truss and displacement of the coupling beam are established. So curve of load-displacement, plasticity formation and development and influences of area of web members on ductility are convenient to obtain. Results show that this model is more convenient and accuracy than finite element method. Finally some valuable conclusions about influences of span-to-depth ratio and area of web member on ductility of the coupling beam are acquired to contribute to design.
Damage-Relevant Evaluation in Appraising Dangerous Buildings
Authors: Qian Tong Hui , Zhang Shi Lei
Published: December 2010

Due to the relevance of item damages on a building, a power transmission mechanism that can reflect the damage relevance is introduced into the dangerous houses hierarchical fuzzy evaluation model (JGJ125-99). The proposed item description model uses a force-delivery tree to describe the relevant relationship among items. A new risk rating formula and a method to calculate the model parameters are addressed. The practical result by applying the approach to Ezhou city primary school in Hubei province shows that the item description model can reduce error judgments in appraising dangerous buildings.
Using Acoustic Emission to Quantify Damage in High-Performance Fiber-Reinforced Cement Composites under Cyclically Compressive Loading
Authors: Nam Sang Hyun , Song Young Jae , Kim Sun Woo , Yun Hyun Do
Published: December 2010

High performance fiber-reinforced cement composites (HPFRCCs) show multiple cracks and a limited damage tolerance capability due to the debonding of the fibers of the cement matrix. For practical applications, it is necessary to investigate the fractural behavior of HPFRCCs to understand the mechanism of the microbehavior of a cement matrix containing reinforcing fibers. We have investigated the acoustic emission (AE) signals in HPFRCCs under monotonic and cyclic uniaxial compressive loads. Four types of specimen were tested. The experimental parameters studied were: the type of fiber (polyethylene or polyvinyl alcohol), the hybrid type (with steel cord), and the loading pattern. The data shows that the progress of the damage in HPFRCCs in the compressive mode is characteristic of the type of hybrid fiber and its volume fraction. From the AE data, the second and third compressive load cycles resulted in a successive decrease in the amplitude compared to the first compressive load cycle. In addition, an AE Kaiser effect was observed in HPFRCCs specimens up to 80% of their ultimate strength. These observations suggest that the AE Kaiser effect has potential for use as a new tool to monitor the loading history of HPFRCCs.
Study on the Effect of Prestress to the Dynamic Characteristics of Truss String Structure
Authors: Luo Yao Zhi , Tong Ruo Fei
Published: December 2010

Truss string structure (TSS) is a new type of large-span space structure which is composed of upper spatial truss and bottom high-strength cables with vertical supports. For certain upper truss, the main affect factor of dynamic characteristics of a TSS are prestress of the cables, pole number, rise-span ratio and vertical span ratio. In modal parameters, modal frequencies is the most direct and easily observed parameter, which largely reflects the stiffness of the structure and plays an important role in the dynamic response of the structure. In this paper, the mode testing experiment and finite element analysis is executed, to study the changes of the lower modal frequencies in different prestressed cables and to study the influence of the prestress to the dynamic properties of TSS.
Damage Detection for Underground Arch Structure Considering Errors in Baseline Model
Authors: Zheng Fei , Xu Jin Yu , Chen Yong , Zhao De Hui
Published: December 2010

Underground arch structure is an important structure form of civil air defense engineering, and its damage detection is an important link in safety evaluation of civil air defense engineering. In this study, a neural networks based damage detection method using the modal properties is presented. Based on the analysis of the dynamic properties of underground arch structure before and after damage, it was proved that the ratio of mode shape was insensitive to finite element model errors. The variation rate of mode shape was taken as the signature for damage detection, and it was proved that the variation of mode shape caused by multiple damage state was transformed into superposition of single damage state. It is not needed to constitute multiple location damage patterns when using the neural networks. A typical underground arch structure is analyzed to demonstrate the effectiveness of the proposed method. When 10%’s modeling errors exists, the damage location and extent can be recognized well.
The Whole Process Simulation and Research on Temperature Field and Thermal Stress for Large Sluice Pier
Authors: Wang Hai Bo , Qiang Sheng , Zhu Zhen Yang , Xie Zhi Qiang
Published: December 2010

Based on the real construction process and field environment of large sluice pier for Caojie Project, considering the factors of surface insulation, internal cooling, the strength of the foundation and environmental climate, the basic theories of temperature field and stress field of concrete and 3D FEM combining with cooling pipe discrete model and iteration method are used to carry out the study of cracking mechanism. According to the 3D dynamic simulation of the temperature filed and stress field for the pier, reasonable temperature control measures are put forward for reference during construction period. The result of the simulation shows that the concept of the exterior thermal insulation and interior pipe cooling measures are of great useful in practice, and the methods should have great reference signification in future.
A Two-Stage Kalman Estimation Approach for the Identification of Large Size Structural Parameters
Authors: Lei Ying , Wu De Ting , Jiang Yong Qiang
Published: December 2010

A new distributed structural damage detection approach based on a two-stage Kalman estimator approach, which is not available in the previous literature, is proposed for the identification of large size structural parameters under limited input and output measurements. A large size structure is decomposed into small size substructures based on its finite element formulation and each substructure is identified by utilizing the two-stage Kalman estimator approach. It can greatly reduce the time of iteration calculation. Numerical example of identifying the parameters of a large-size plane truss bridge is conducted. Simulation results show that the proposed approach is able to identify structural systems.
Settlement Monitoring of Passenger Railway Tianjin to Qinhuangdao
Authors: He Yue Lei , Shi Rong
Published: December 2010

Settlement monitoring in the process of roadbed construction is one of the key technologies in the quality of passenger railway roadbed construction. By the specific circumstances of the roadbed project of passenger railway Tianjin to Qinhuangdao, outlines the meaning and content of the purpose of roadbed settlement monitoring, and describes the characteristics of a variety of settlement monitoring, function and layout of facilities in implementation, the requirements of technology, etc. Investigate and analyze the settlement monitoring information management based on construction control.
Characteristics and Application of BOTDR in Distributed Detection of Pile Foundation
Authors: Piao Chun De , Shi Bin , Gao Lei
Published: December 2010

As a new type of detection technique, BOTDR can conduct the distributed detection of pile foundation. Based on the characteristic that BOTDR is exposed to the effects of both temperature variations and deformation, the paper develops the temperature compensation sensor, and analyzes the effect of temperature variations upon the strain sensing during the distributed detection of pile foundation. Combined with the static load test of the bored pile in the engineering site, the paper examines the measured values of temperature variations in the surrounding environment during the detection of pile foundation, and finds out from the test result that the effect of the surrounding temperature upon the pile strain is negligible. Through analyzing the pile shaft bearing capacity of the test pile under both vertical loads and horizontal loads, this paper deduces the theoretical formulae for the axial force, the side resistance, the compression, together with the deflection of the pile shaft, and then applies these calculating formulae to the practical engineering project. From the comparative analysis of the calculated results and the measured results, it can be found that these two results are almost the same, which finally proves that the distributed detection technique of BOTDR can effectively detect the pile shaft deformation under loads, and can provide the precise detection of pile foundation.
Structural Design and Analysis of a Steel Vine Bridge
Authors: Zhang Hao Yu , Zhou Wei , Gao Bing
Published: December 2010

A steel footbridge with a 27m net span, a worm-shaped curve and a vine bridge style was proposed to be constructed in Diexi city of Sichuan, China. Considering the appearance and the functional requirement, the bridge is designed as follows: the section outline is composed of 21 different ellipse-shaped transverse ribs with 1.5m spacing, and the transverse ribs are connected by 12 longitudinal ribs. Comparison between two optional structure schemes is carried out. Considering the mechanical performance and economy, the structure scheme, a truss structured system at lower part of the bridge, is adopted. Internal force analysis, member design and deformation calculation of the structure are accomplished. Finite elements analysis with ANSYS shows that the welded joints can meet the bearing capacity requirement. Connection between the bridge and the foundation platform is also presented in this paper.
Bidirectional Moving Vehicle Load Identification from Bridge Responses
Authors: Yu Ling , Wang Xue Gang
Published: December 2010

A time domain method on bidirectional moving vehicle load identification from plate bridge responses is proposed in this paper. The bridge deck is modeled as a plate based on the theory of plate and the vehicle loads are modeled as two groups of axle loads moving on top of the bridge deck in two opposite directions. The equation of motion of the bridge-vehicle system is formulated in state space and the bidirectional moving load identification problem is formulated as a damped least-squares problem and further solved using the dynamic programming method with regularization on the solution. Some numerical simulations show that the proposed method is correct and effective and can be used to identify the bidirectional moving vehicle loads from the bridge responses with an acceptable accuracy.
Technique Research on Strength Estimation of Pile Foundation Based of Model Analysis
Authors: Wang Zheng Jun , Wang Qiang , Liu Chun Hua , Hu Kun , Zhang Dian Hong
Published: December 2010

In order to realize non-destructive testing of concrete strength of pouring stakes at the construction stages, the paper establishes two kinds of mathematics models between the concrete strength and the sound-speed through experiment on concrete test squares, model stakes and engineering piles ─ all of differently designed strength with method of ultrasonic. The concrete average strengths of the pouring piles were reckoned through engineering piles of practical testing and the errors were within the allowable range. So the validity of mathematics models was proved.
Negative Selection Algorithm Using Natural Frequency for Novelty Detection under Temperature Variations
Authors: Li Miao , Ren Wei Xin
Published: December 2010

The vibration features are affected by damage in structure and environmental conditions while the bridges are in the operation. Environment effects should not be ignored in making correct diagnoses of structures. Negative selection algorithm inspired by immune system has the capability for self-nonself discrimination. Temperature effect on natural frequency is analyzed in the paper, and the algorithm based on Euclidean distance is applied to natural frequencies of structures under temperature variations. The results indicate that negative selection algorithm using natural frequency passes the false-positive tests, and effectively detect the anomalous condition of structure under varying temperature.
Stress Concentration and Deflection of Box Girder under Shear Lag Effect
Authors: Zhang Yu Hong , Yang Zi Jiang , Liu Shi Zhong
Published: December 2010

The shear lag effect on box girders has been studied by quite a few researchers for many years. However, most of studies are related to shear lag formulas and analytical methods and very few have investigated the effect of stress concentration and deflection. The present study investigates the stress concentration and deflection under shear lag effect in a continuous box girder and a simply supported beam by using the three-dimensional finite element method. The whole girder is modeled by shell elements, and an extensive parametric study with respect to the geometry of a box girder is carried out. The influence of finite element mesh on the shear lag is carefully treated by the multi-mesh extrapolation method.
The Semi-Active Control Considering Structure-Basement-Pile-Soil Interaction
Authors: Li Yan Tao , Zhou Zhan Xue
Published: December 2010

The interaction system which includes pi1e-supported tall buildings with multistoried basements and the adjacent medium of soil subject to the impact of earthquake is formulated in terms of the spline subdomain method,semi-analytical infinite element method and the bend-shear model of beam element,respectively.Taking advantage of the instantaneous optimal control algorithm, structure-basements-piles-soil interaction effect on the semi-active control is considered. It is shown that the results of structural control have obvious difference between the interaction system and the fixed-end system.The response of the former may be less about 10 percent than the latter in the paper.The dissipative capability of the structure self may be ignored largely if the interaction isn’t considered.When designing the system of the semi-active control, especially for some tall buildings,soil-structure interaction should be taken into consideration.
Numerical Analysis of Causes and Cures of Longitudinal Reflection Cracking on Side-by-Side PC Box-Girder Bridge Deck
Authors: Zhuang Yi Zhou , Ji Tao , Chen Bao Chun
Published: December 2010

Finite element analysis, based on various construction and service stages, of a genetic bridge was carried out to find the potential reasons causing longitudinal reflection cracking on top of bridge deck as well as the cures for solving this problem. Meanwhile, the effect of applied transverse posttensioning magnitude and tendon location as well as bearing pads’ supporting restraint was modeled in the FEA to investigate their effect on the distribution of transverse posttensioning force along the joints between adjacent box-girders. Results show that (1) transverse posttensioning and diaphragms reduce efficiently the tensile stress on top of deck; but this efficiency slows down significantly in bridge corner area, where exists still relatively higher tensile stress than other locations; (2) In some cases of loading combination, most locations on top of deck along the joints exist transverse tensile stresses, but the magnitude is less than 0.7Mpa, which could not cause the cracking if the decking concrete cover and keyway grout are properly selected and cast to the designated specifications; (3)Two patterns of transverse posttensioning output almost same result in the clamping stress along the joints for this proposed particular bridge model; (4)The vertical spacing between two tendon locations (upper and low level) should be farther spaced than the currently specified 1/3 girder depth so that less tensile stress or compressive stress is expected on top of deck; (5) The restrain from bearing pads modeled in this FEA has little effect on the stress distribution along joints between box girders.
Finite Element Model Updating Based on Direct Optimization Technique
Authors: Ding Bei Dou , Lv Heng Lin , Ji Yong Sheng
Published: December 2010

Setting up of an objective function, update parameters and use of robust optimization algorithm are three crucial steps in FE model updating. In order to calculate the gradient of the objective function, analytic optimization algorithm is not easy to be achieved, while the direct optimization algorithm may achieve the objective function optimization simply by comparing the size of the objective function to move the iteration point. In this paper, the eigenvalues and mode shapes are used as the optimization objective function, the direct optimization algorithm is adopted, an updated finite element model is achieved, and a numerical example is given.
Computer Aided Health Monitoring System for Super-Huge Spacial Cable Structures
Authors: Zhang Qi Lin , Li Da Lin
Published: December 2010

Increasingly large and complex structures make it more complicated in analysis, designing and construction, and through the amplification effect caused by the interaction of various parts of the structure, any tiny error in any link could cause huge damage to the building. However, the relative analysis theory and design method are not consummate enough to assess the influence of all kinds of errors. Under this circumstance, structural health monitoring system is an important guarantee to ensure the safety of the structures in both construction and operation stage, and at the same time contributes to make up for the deficiency of theory [1-2]. The Expo Axis project is the largest single project in Expo Site 2010 Shanghai. The Expo Axis project has adopted a whole new architecture form. The roof design as giant light cable-membrane structure about 1000 meter long and about 80 meter width. The computing displacement of the membrane roof is close to 4m. In order to ensure the safety of this structure, a real-time and long-term computer based health monitoring system is applied in the Axis structures.
Dynamic Test and Analysis of Concrete Filled Steel Tube Arch Bridge
Authors: Wang Li Xian , Di Sheng Kui
Published: December 2010

Based on random vibration theory, virtual response is obtained from the measured acceleration signal of Yantan Yellow River Bridge of Lanzhou under ambient excitation, Yantan Yellow River bridge's modal parameters were identified by using the peak picking and stochastic subspace identification, analyzed from theoretical and experimental aspects, compared with the finite element model results and verified the reliability of recognition results. The identified dynamic properties can be served as the basis in the finite element model updating, damage detection, condition assessment and health monitoring of the bridge.