bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on Cast-Steel Joints for Nantong Sports Exhibition Center
Authors: Zhao Cai Qi , Ma Jun , Ma Hong Tao
Published: December 2010

Cast-steel joints characterized in strong adaptability are widely applied in various long span spatial structures. At present, there is no national design specification available on cast-steel joints. Therefore, it is quite a necessity to conduct full-scale test or model test on cast-steel joints suffering complicated forces. This Paper has, taking Nantong Sports Exhibition Center as an example, conducted the experimental study of some important joints, and compared with elastic-plastic nonlinear finite element analysis result. According to the result, the fracture morphology of joints, stress distribution and bearing capacity of joints obtained from the elastic-plastic nonlinear finite element analysis are consistent with those of measured result, proving that the analysis theory applied in engineering design is basically suitable for the actual working condition of cast-steel joints and the joints are sufficiently safe.
Analysis on Flexural Behavior of Concrete Beams with CFRP-GFRP Bars
Authors: Cai Jiang Yong , He Yan Tao , Liu Ying Ying , Xiong Jing Liang
Published: December 2010

This paper presents a method for designing and predicting the flexural behavior and capacity of concrete beams with mixed CFRP-GFRP bars. The design of the section with CFRP-GFRP bars is expected to obtain better performance in serviceability and deformability comparing with the section with only CFRP bars or GFRP bars by realizing successive rupture of CFRP and GFRP bars in the section. The corresponding equations are proposed to calculate the flexural capacity, strain and stress of the section. The calculating values of flexural capacity are compared to existing test results and it is found that the calculating values are in good agreement with the experimental results. Further analysis on a calculating example shows that the section with CFRP-GFRP bars designed appropriately presents excellent performance.
Flexural Capacity Study on Square Tube Filled with Steel Reinforced Concrete Members
Authors: Zhao Tong Feng , Li Hong Nan , Yu Jia Huan
Published: December 2010

Moment-deformation curves of square steel tube filled with steel reinforced concrete subjected to bending load were simulated by the ABAQUS software. Calculated and experimental curves agreed well with each other. Through studying further the calculated member, the behavior of materials subjected to moment is given. Finally, flexural capacity formula of square steel tube filled with cross steel reinforced concrete is proposed.
Finite Element Analysis of Loading Characteristics of Long-Short Piles Composite Foundation with Cushion
Authors: Sun Lu Yuan , Han Zhi Jun , Ge Xin Sheng , Bai Xiao Hong
Published: December 2010

Three-dimensional nonlinear finite element analysis on long-short piles composite foundation is finished by using the Drucker-Prager yield criterion and ANSYS procedure. The influences of length and modulus of long and short pile on long-short piles composite foundation loading characteristics are analysed through research on nine long piles and sixteen short piles. The results are given as follows. The composite foundation settlement decreases linearly with the length of long pile increases. The composite foundation settlement has hardly decreased with the length of short pile increases. These conclusions are of referential value for engineering.
Prodution of Concrete Aggregates with High Strength by Using the Wastes
Authors: Wang Jin Bang , Zhou Zong Hui
Published: December 2010

Several series of concrete aggregates with different content of steel slag, blast furnace slag, coal gangue and fly ash were prepared. The reasonable ratio of raw materials and process parameters to prepare the aggregates were determined by measuring the water absorption, crush indicators and apparent density of the aggregates. The mineral composition and morphology of the aggregates were analyzed by XRD, SEM and EDS. The results showed the aggregate with about 30% steel slag, 50% slag, 20% gangue, and calcined at 1300°C for 90 minutes had the best performance. The water absorption of the aggregate is about 1.55% which is lower than that of the natural aggregates (about 2.2% on average). Both the crushing index (about 11.39%) and the apparent density (2672 kg/m3) of the aggregate meet the requirements of national standards.
Influence of Environmental Conditions on Temperature Field of Concrete
Authors: Shen De Jian , Luan Hao , Jia De Qing , Zhang Li
Published: December 2010

The temperature cracking of early-aged concrete is often met by constructors in recent years, because of large temperature difference of core and surface of concrete. Experimental study on temperature field of concrete under different environmental conditions is conducted. Different environmental conditions such as wind speed, formwork removal, sun radiation and conservation are involved. The influence of environmental conditions on the peak value of rising temperature, temperature difference of core and surface and descending speed of temperature of concrete is studied. Result obtained from this study can be used in controlling of early-age cracking of concrete.
Research Situation on the Performance-Based Seismic Design Method for Reinforced Concrete Structure
Authors: Qi Yong Le , Han Xiao Lei , Peng Xue Ping , Zhou Yu , Lin Sheng Yi
Published: December 2010

Various analytical approaches to performance-based seismic design are in development. Based on the current Chinese seismic codes，elastic capacity calculation under frequent earthquake and ductile details of seismic design shall be performed for whether seismic design of new buildings or seismic evaluation of existing buildings to satisfy the seismic fortification criterion “no damage under frequent earthquake, repairable under fortification earthquake, no collapse under severe earthquake”. However, for some special buildings which dissatisfy with the requirements of current building codes, elastic capacity calculation under frequent earthquake is obviously not enough. In this paper, the advanced performance-based seismic theory is introduced to solve the problems of seismic evaluation and strengthening for existing reinforced concrete structures, in which story drift ratio and deformation of components are used as performance targets. By combining the features of Chinese seismic codes, a set of performance-based seismic design method is established for reinforced concrete structures. Different calculation methods relevant to different seismic fortification criterions are adopted in the proposed method, which solve the problems of seismic evaluation for reinforced concrete structures.
Analysis on the Causes and Control of Pre-Mixed Concrete Floor Cracks
Authors: Zhang Li Qun , Li Rui Jun , Xu Yong Feng
Published: December 2010

With the development of construction industry, casting reinforced concrete floor has replaced pre-cast concrete hollow block floor with pre-stress. A large number of irregular cracks appear on the floor, which has become the biggest problem related to the residential projects’ quality. This paper analyses the causes of cracks and the major factors of the pre-mix concrete components and relevant material performances. Combined with current concrete technology, supply of raw material and production, and construction of concrete realities, controlling cracks can be begun to consider from two aspects, namely increasing the concrete strength and decreasing the concrete shrinkage. This paper puts forward the following measures to control cracks: 1. strict control of the water for concrete; 2.strict control of concrete slumps; 3. improving the quality of aggregate (such as sands or stones) and increasing the number of coarse aggregate; 4. Reasonable choice for additive; 5.controlling the amount of adulterant in concrete.
Performance of Screen Grid Insulating Concrete Form Walls under Combined In-Plane Vertical and Lateral Loads
Authors: Abdel-Mooty Mohamed , Haroun Medhat , El Maghraby Yosra , Fahmy Ezzat , Abou Zeid Mohamed
Published: December 2010

Insulating Concrete Forms (ICF) walls generally comprise two layers of Expanded Polystyrene (EPS), steel reinforcement is placed in the center between the two layers and concrete is poured to fill the gap between those two layers. ICF’s have many advantages over traditional methods of wall construction such as reduced construction time, noise reduction, strength enhancement, energy efficiency, and compatibility with any inside or outside surface finish. The focus of this study is the Screen Grid ICF wall system consisting of a number of beams and columns forming a concrete mesh. The performance of ICF wall systems under lateral loads simulating seismic effect is experimentally evaluated in this paper. This work addresses the effect of the different design parameters on the wall behavior under seismic simulated loads. This includes different steel reinforcement ratio, various reinforcement distribution, wall aspect ratios, different openings sizes for windows and doors, as well as different spacing of the grid elements of the screen grid wall. Ten full scale wall specimens were tested where the effects of the various parameters on wall behavior in terms of lateral load capacity, lateral displacement, and modes of failure are presented. The test results are stored to be used for further analysis and calibration of numerical models developed for this study.
Dynamic Load-Displacement Behavior Simulation of RC Columns Considering Strain Rate and Nonlinearity Effects
Authors: Jiang Zhou , Xu Bin , Zeng Xiang , Tang Liang
Published: December 2010

In this study, numerical simulations on the dynamic load-displacement behavior of typical RC columns under dynamic loadings considering the strain rate effect and the influence of shear deformation, geometrical nonlinearity, plastic hinge zone were performed with a dynamic fiber element model, where the dynamic constitutive model of concrete considering the strain rate effects proposed by the CEB-FIP code (1990) was employed. The developed dynamic fiber element models with and without the consideration of shear deformation were employed to simulate the load-displacement behavior of RC column specimens with different shear span to depth ratios and under different loading speeds. The simulation results were compared with test measurements. Results show that difference between the simulation results with and without the consideration of shear deformation can be detected, especially for specimens with small shear span to depth ratios. The simulation results are closer to the test measurements for all of the specimens when shear deformation is considered. The shear deformation effect on the dynamic load-displacement behavior of short columns subjected to dynamic loadings is needed to be considered.
Experimental Research on Eccentric Compressive Performance of Steel Tube-Reinforced Concrete Column
Authors: Guo Quan Quan , Zhao Yu Xi , Shang Kun
Published: December 2010

Eccentric loading experiment of 13 steel tube-reinforced concrete columns and a reinforced concrete column is implemented. The whole process from the start load on the steel tube-reinforced concrete column until damage has been researched. Change of ultimate bearing capacity with eccentricity, longitudinal reinforcement ratio, position coefficient has been studied, and deflection curve and load-vertical displacement curve under eccentric compressive load were obtained. Failure characteristics of steel tube-reinforced concrete were divided into two different type, small eccentric damage and big eccentric damage. With the same conditions, when steel tube ratio of steel tube-reinforced concrete was 2%, its ultimate bearing capacity was nearly double of reinforced concrete columns.
Design Thermal Gradients for Straddle Track Girders
Authors: Zhang Tao , Bai Hai Feng
Published: December 2010

Thermal stresses and deformation in straddle track girders can be significant in comparison to dead or live load responses. In present paper, a comparison of current design-code provisions is present. The temperature distributions are obtained by a numerical technique for the solution of the Fourier heat-transfer equation and its boundary conditions. This technique is based on the finite-element method and takes into account the geometry of cross section of the track girder, thermal properties of concrete, and the climatic conditions. A field test is conducted on a track girder to verify the analytical models. The results of a temperature gradient study developed to evaluate design thermal vertical differences for the straddle type track girder are presented. The analysis suggests that straddle track girders are designed for larger temperature gradients than the codes suggested.
Experimental Study on Seismic Behavior of Recycled Concrete Perforated Brick Masonry
Authors: Guo Zhang Gen , Sun Wei Min , Wang Jian , Chen Jian Long , Xu Yi Fan
Published: December 2010

In order to investigate the seismic performance of recycled concrete perforated brick masonry, an experiment was conducted on three specimens of recycled concrete perforated brick walls subjected to low frequency reversed cyclic load test. The loading process, failure mechanism, ultimate bearing capacity was studied. The seismic behavior such as hysteretic characteristics, backbone curve, ductility, energy dissipation capacity were analyzed too. The test results show that the seismic performance of recycled concrete perforated brick masonry is similar to those of ordinary concrete perforated brick walls. The test results also indicate that the seismic behavior of recycled concrete perforated brick masonry is good. The specimens have good hysteresis loops and ductility, strong energy dissipation capacities.
Ultimate Load of Composite Beam Based on Effect for Cracks in the Brittle Material on Slip of Shear Connectors
Authors: Liu Qiong Xi
Published: December 2010

In engineering, the excessive slip of shear connectors will arouse the failure of the beams, and cracks in the brittle material element can increase the slip. In this paper, composite beam is composed of the brittle and ductile material elements and there are cracks in the brittle material element. Based on the relation between the slip strain and flexural rigidity, defining rigidity coefficient as there are cracks in the brittle material element, the total change in the slip strain at a given section due to cracking of the brittle material is obtained. The end slip that incorporates the effects of the brittle material cracking is calculated by integrating the slip strain. Letting the end slip equaled to the ultimate slip of shear connectors, the ultimate load formation of composite beam is gotten.
Study on Flexural Behavior of the Steel-Full Depth Precast Concrete Panel Beams
Authors: Dai Yi Min , Li Can , Ouyang Jian Xiang
Published: December 2010

Based on twelve push-out specimens with different holes filling different materials,the paper compared and analyzed the capacity and the corresponding slip value of the stud shear connector.Meanwhile, tests were also conducted on three composite steel-FDPCP(Full-Depth Precast Concrete Panel) beams with different holes shape and degree of shear connection to investigate the characteistics of load-displacement,load-deflection,load-strain of the total cross section and monolithic action of the entire cross section in the paper. The results show that, as to the two different kinds of holes shape ,the strength of the stud shear connectors of square push-out specimens was huger than that of circular specimens with the same condition; the strength of stud shear connectors in steel-concrete composite structure was decided by the strength of concrete surrounding the shear in the holes, with increasing concrete strength, the strength of stud shear connectors improved greatly; the composite steel-FDPCP beams failed in bending,plane section was maintained in composite beams throughout the testing process.the composite steel-FDPCP beams have some merits :good bearing capacity, good anti-bend capability, fast pile-driving pace and perfect work behaviors as a whole;the ultimate flexural capacity of the composite steel-FDPCP beams with a full shear connection is close to that of a partial shear connection. The outputs of this study are very useful for further understanding of the characteristics of the composite steel-FDPCP beams,it is also expected that the results presented in this paper should be valuable for the design of the composite steel-FDPCP beams.
Full-Process Analysis of Pretensioning Construction of Dalian Gym
Authors: Wang Hua Jie , Fan Feng , Qian Hong Liang , Zhi Xu Dong , Zhu En Chun
Published: December 2010

As a inclined mega-grid suspend-dome, the prestressing constructi of Dalian gym is very complex. Full-process analysis for the pretensioning scheme should be done before construction. Compared with other pretension methods, a relatively proper scheme of stretching radial cable is put forward and analyzed using construction full-process simulation. The length of active cables without stress is controlled by changing temperature, so pretension is put on cables; Cable tension and removing of temporary support system are simulated using birth and death technology, therefore the structure response of different construction stage and in which stage removing temporary supports is proper are acquired, which provide referenced data for controlling construction safety and precision.
Experimental Study on Neotype Anchor System in Tower of Cable-Stayed Bridge
Authors: Tan Dong Lian , Qin Feng Jiang , Jin Di
Published: December 2010

Concrete is used in tower, and steel is used in anchor zone. It can make full use of the two materials’ nature. It can not only satisfy the tower’s stressed aptitude, but also can reduce the cost of construction. In this paper, the full size model has been designed and constructed. The test investigation of the statical performance have been proceeded. The results show that the neotype anchor system can make full use of the materials’ nature and is in good working order. The anchor system with enough bearing capacity satisfies the operating requiements of the cable-stayed bridge.
Research on Flexural Behaviors of Cementitious Composite Material Formwork without Being Removed Concrete Beams
Authors: Zhou Shuang Xi
Published: December 2010

Based on experiments on two beam specimens (one is a concrete beam with a formwork without demoulding, another is a normal concrete beam), the basic mechanical properties of the flexural beam with a formwork without demoulding, in the condition of monotonic loads were studied, including failure patterns, normal section bearing capacities, change rules of deflections, concrete strain of midspan, strain of strengthened reinforcing steer and so on. The comparison of bearing capacity is also made between a concrete beam with a formwork without demoulding and an ordinary concrete beam. The results indicate that by calculating bend-bearing capacity in current code, a beam with a formwork without demoulding is as safe as an ordinary concrete beam, a concrete beam with a formwork without demoulding meets the requirements of deflection limit value. Its bend-bearing capacity is approximate to an ordinary concrete beam.
Ultimate Bearing Capacity Research on the Steel Tube Composite Column Filled with Steel Reinforced Concrete
Authors: Sun Shan Shan , Zhao Jun Hai , Wei Xue Ying , Xiao Hai Bing
Published: December 2010

The ultimate load-bearing capacities of axially-loaded steel tube composite column filled with steel reinforced concrete under three-dimensional stress based on the unified strength theory are analyzed in this paper. The influence of thickness-length ratio and scale effect are considered by introducing the reduction factor of equivalent constraints and concrete strength reduction factor, respectively. The nonlinear three-dimensional finite element analysis of the steel tube composite column filled with steel reinforced concrete is performed by the finite element software ANSYS. The numerical and the analytical results are compared with experimental results and good agreement can be observed. A series of numerical simulation technologies is studied and described in detail, such as selecting element type, defining material model of steel and concrete, establishing global finite element model with discrete reinforced bars elements, applying loads to the specimens, and setting solution controls option. The results indicate that ANSYS finite element software may well simulate the behavior of the steel tube composite column filled with steel reinforced concrete under axial compression through reasonably selecting parameters.
Structure-Soil Interaction of Buried Corrugated Steel Arch Bridge
Authors: Zhang Miao Xin , Liu Bao Dong , Li Peng Fei , Feng Zhi Mao
Published: December 2010

Corrugated steel plate and surrounding soils are working together to share the load in buried corrugated steel structures. It is complicated to consider the structure-soil interaction, so the finite element method has already become the chief means of complicated structure analysis. Based on a practical project, considering structure-soil interaction, by using the finite element program of ANSYS, the paper set up a 2-D FE model and analyzed the soil pressure, the structural deformation and the internal force under different load conditions in detail. The analysis shows that structure-soil interaction has brought about stresses redistribution of surrounding soils, and adverse effects of soil pressure and displacement were limited. The variation range of soil pressure on the crown of arch increases with the load increases and the peak value of soil pressure approach to the code value and a rebound appears in the vehicle load range. The tendencies of vertical soil displacement are nearly the same to different load conditions, and the peak value of moments has an obvious change and can be influenced greatly by deflective load.
Influence of External Tendons on Dynamic Characteristics of Box Girder with Corrugated Steel Webs
Authors: Chen Jian Bo , Liu Bao Dong , Li Peng Fei
Published: December 2010

Based on Miyamoto’s method, the natural frequency of prestressed box girder with corrugated steel webs considering the impact of external tendons was obtained. And the result was modified based on the finite element model. It shows that: the external tendons will reduce the natural frequency of bridge with reduced range of about 3%. Beneficial references were provided to the layout of external tendons in order to avoid the resonance between the box girder with corrugated steel webs and the external tendons.
Study on Stability of a New Prestressed SINGLE-Layar Spherical Lattice Shell
Authors: Yin Zhi Xiang , Tian Li Min , Gao Zhe
Published: December 2010

Prestressing of lattice shell is realized by cable, and author put forward a new kind of layout: The prestressing has been brought to bear by hoop and radial element of single-layer lattice shell, which avoid cable's effect on architectural purpose. The element has been made to sleeve, and the magnitude of prestressing is dominated by bolt. Article shows an example of K6, K8 single-layer spherical lattice shell, and the prestressing have been exert on partial ribs and hoops. The prestressing has been calculated by element axial force under normal loading. Stability of shells have been studied, and show the deformation satisfy the criteria under normal loading; The ultimate capacity has been improved obviously, loads transfer is rational. The new layout of prestressing is a promising technique.
Finite Element Analysis of Middle Long Columns of High-Strength Concrete Filled Square Steel Tube with Inner CFRP Circular Tube under Axial Load
Authors: Li Guo Chang , Di Cheng Yi , Li Shu Jie
Published: December 2010

With the development of computer science, the finite element method has been used widely. The paper used the ABAQUS finite element analysis software to carry out the finite element analysis on the middle long columns of high-strength concrete filled square steel tube with inner CFRP circular tube under compressive load. The results of finite element analysis were obtained, which agreed well with theoretical data. This conclusion proved the correctness and feasibility of finite element model.
Experimental Study on Shear Behavior of Light Wall Composed of Oriented Structural Straw Board and Tennon-and-Mortise Connection Frame
Authors: Xie Qi Fang , Xiong Hai Bei , Lu Xi Lin
Published: December 2010

Combined with the merits of light wood frame structure and Chinese ancient wood structure, a light wall composed of oriented structural straw board (OSSB) and tennon-and-mortise connection wood frame (TMCWF) was developed. The wall build-up with several wall-modular those are composed of wood frames and panels based on its width, the wood frame members are connected with tennon-and-mortise, and the panel is OSSB which is cheap and low-carbon, so the wall have many merits such as lower cost, better earthquake-resistance and good to environment protection. To research the shear behavior of the light wall composed of OSSB and TMCWF, nine wall-modular were tested under level unidirectional loading. The performances of the specimens such as the damage characteristic, shear capacity and rigidity are obtained. Factors that influence the shear capacity and elastic rigidity, including space of vertical frame members, nail space, panel thickness, type of panel and vertical load, were analyzed. And the shear behaviors of the light wall composed of OSSB and TMCWF and the light wood frame wall were compared. Experimental results show that the shear strength and rigidity of the developed wall with TMCWF are higher than those of the light wood frame wall. And the panel type, the panel thickness, nail space of the panel are the major factors to influence the shear strength of the wall-modular.
Model Test Investigation on Rectangular Section Composite Micro-Pile Structure for Earth Slope Reinforcement
Authors: Liu Xiao Li , Zhang Dan Dan , Liu Kai
Published: December 2010

Model test investigation on rectangular section composite micro-pile structure used for earth slope reinforcement has been performed, including the mechanical and deformation properties and pile spacing influence on anti-sliding capacity. Test results have shown the main following conclusions. For the rectangular section composite micro-pile structure and the similar soil in tests, micro-pile row spacing along the lateral load direction ranging from 4D to 6D (D is the diameter of micro-pile) can provide higher anti-sliding capacity. Active earth pressure of the first row pile is larger than that of other piles when the anti-sliding potential of composite micro-pile structure is fully developed. Relative deformation of the first row pile is larger than that of the middle and last row piles above the slip surface, while relative deformation of the last row pile is larger than that of other piles beneath the slip surface. The main failure mode of the rectangular section composite micro-pile structure can be regarded as bending failure in certain range near the slip surface.
Structural Design and Finite Element Analysis of Unfolding Process for All Composite Folding Wing of UAV
Authors: Lv Peng , Lv Sheng Li , Yang Guang Jun , Zeng Qing Na , Tong Xiao Yan
Published: December 2010

This paper discusses the unfolding form of the folding wing and its application to special UAV. The main investigations involve aspects such as unfolding process of the special UAV’s folding wing, contour structure of the complete unfolding, the choice of composite materials for the folding wing and its overall performance parameters. Modeling and dynamics analysis are made for all-composite wing through finite element analysis and calculating software. The unfolding process is also simulated. The result shows that the wing’s first-order frequency is low, second-order frequency and third-order frequency are close at different sweep angles. The wings are apt to happen flutter coupling in flutter analysis. With the continued folding of the wing, the wing’s natural frequency decreases significantly at different orders. The conclusions can provide effective basis for the study of wing rotational rate, unfolding time and impact action.
Preparation of Exfoliated Graphite by Microwave Using Natural Graphite with Different Particle Sizes
Authors: Yu Kun
Published: December 2010

Three natural graphite flakes (35, 50 and 80 mesh) were used as raw material. Exfoliated graphite (EG) was prepared by rapidly heating residue H2SO4-graphite intercalation compounds (RGIC) in a muffle and by irradiating it in a microwave oven, respectively. Results show that the exfoliation volume of EG decreases with decreasing the raw graphite particle size. Compared with muffle heating, microwave irradiation is more helpful for the exfoliation of RGICs, especially for the small particle samples.
Synergistic Effect of MgO-Based Expansive Agent and Shrinkage Reducing Admixture on Compensating the Shrinkage of Cementitious Materials
Authors: Zhang Zhi Bin , Xu Ling Ling , Tang Ming Shu
Published: December 2010

In order to improve dimensional stability of cementitious materials, synergistic effect of shrinkage reducing admixtures (mixture of glycol ethers and siloxane, SRA) and MgO-based expansive agent (MEA) burned at 850 °C, 950 °C, 1050 °C and 1200 °C for 1 h on the deformation of cement paste was investigated while being cured in water of 20 °C, 40 °C and 60 °C, sealedly by polyethylene sheet at 20 °C, 40 °C and 60 °C as well as in simulated using environment. The results illustrated that combined use of SRA and MEA (burned at 850 °C and 950 °C) could compensate the shrinkage of cement paste effectively, and MEA also could make up for the shortage of SRA whose shrinkage-reducing ratio decreased at later age. In the simulated using environment, the paste both with SRA and MEA (burned at 850 °C and 950 °C) was in micro-expansion condition, and the average deformation increased slowly till 240d, and the deformation amplitude reduced to the half of the control sample. Then hydration of MEA in the present of SRA was examined by gravimetry. The results indicated that the presence of SRA retarded the hydration of MEA, but with prolonged curing, the hydration degree of MEA with or without SRA tended to be the same.
Parallelizing a Modified Particle Swarm Optimizer (PSO)
Authors: Yang Bin , Zhang Qi Lin
Published: December 2010

Recently, a modified Particle Swarm Optimizer (MLPSO) has been succeeded in solving truss topological optimization problems and competitive results are obtained. Since this optimizer belongs to evolutionary algorithm and plagued by high computational cost as measured by execution time, in order to reduce its execution time for solving large complex optimization problem, a parallel version for this optimizer is studied in this paper. This paper first gives an overview of PSO algorithm as well as the modified PSO, and then a design and an implementation of parallel PSO is proposed. The performance of the proposed algorithm is tested by two examples and promising speed-up rate is obtained. Final part is conclusion and outlook.
Coefficient Distribution Method for Minimum Weight Design of Large-Span Determinate Trusses
Authors: Du Wen Feng , Zhou Zhi Yong , Wang Sheng Xiang , Yu Fu Dong
Published: December 2010

The minimum weight design method of large-span statically determinate trusses satisfying the displacement constraint is studied. The displacement calculation formula is provided, and the critical condition of minimum weight design satisfying the condition of allowed displacement is educed using Cauchy inequality. The distribution coefficient, which is used to obtain the minimum weight design, is defined and the coefficient distribution method is proposed. An engineering example is analyzed using the coefficient distribution method above, and the compared results are discussed. Study results show that the proposed method, coefficient distribution method, is correct，reliable and effective.
Optimal Grillages by 3-Nodes Triangle Finite Element
Authors: Zhou Ke Min , Li Xia
Published: December 2010

By triangle finite elements, grillages with stress constraints are optimized. From it an optimal beams systems or plate with reinforced ribs is obtained. A truss-like continuum material is adapted. The material distribution field in design domain is optimized by fully-stressed criterion. The densities and orientations of the beams or reinforced ribs at nodes in grillages are taken as design variables. These densities and orientations vary in design domain continuously. The optimal distribution fields of moments, deformation and material are obtained simultaneously. Subsequently the discrete structures are determined based on the optimal distribution fields. A very simple geometry matrix of triangle plate element is given. The stiffness matrix of truss-like continuum in triangle element is derived. The optimization iteration procedure is suggested. The optimization procedure is accomplished by computer program automatically.
A Novel Acoustic Emission Technique to Monitor Damage Evolution in Masonry Structures
Authors: Antonaci Paola , Bocca Pietro G. , Masera Davide
Published: December 2010

The aim of this work is to analyse the mechanical response of the masonry specimens under long-term action by means of cyclic tests. To this end laboratory tests were carried out at the Non-Destructive Testing Laboratory of the Politecnico di Torino. The Acoustic Emission technique was employed to assess the damage evolution, and the mechanical properties decay in order to evaluate the extent and the evolution of micro and macro-cracking due to cyclic action until structural collapse in masonry blocks and mortar layers by means of a novel Acoustic Emission analysis technique.
The Design and Application of Piezoelectric Friction Damper with Self-Powered and Sensing Control System
Authors: Dai Na Xin , Tan Ping , Zhou Fu Lin
Published: December 2010

To make the active and semi-active vibration control system in civil engineering get rid of external power supply, a new piezoelectric friction damper with self-power and sensing is designed in this paper and a semi-active control system based on this damper is presented. This system includes three key parts: a piezoelectric friction damper, a power generator based on the piezoelectric stack electro-mechanical energy conversion and a control circuit. It makes full use of the direct and converse piezoelectric effect. At the same time, it also overcomes the deficiency that the frictional force as damping can not be accurately desired in semi-active vibration control system. On the basis of it, the control equation of PFD is formulated. Numerical simulations for seismic protection of story isolation equipped with this system excited by a historical earthquake are conducted by MATLAB. Skyhook control is used to command a piezoelectric friction damper in the semi-active control. It is noticed that only one accelerometer is needed to monitor the response to realize the skyhook control, which greatly simplifies the classical semi-active vibration control system.
Mechanical Performance of Large Cantilevered CFT Beam-Column Joint in Jiangyin Magic Cube Time Square
Authors: Wang Fei , Luo Yong Feng , Guo Xiao Nong , Xu Han , He Ping
Published: December 2010

The leading building in Magic Cube Time Square in Jiangyin is a rare large-cantilevered structure in China, with the standard floors overhanging 9m outwards. Concrete filled tube columns in large diameter and steel beams are applied in the peripheral part of the building frame. In this research, the full-scale test is conducted to investigate the mechanical performance of the concrete-filled beam-column joint. Self-balanced loading frame with dimensions of 15m×10m×10m is built due to the complexity of the joint, the greatness of load and the difficulty of loading condition. Meanwhile, the finite element model is generated to inspect the performance of the beam-column joint under the test loads for verification. Through comparisons of test results and FEM results, good mechanical performance and reasonable load transfer mechanism of the joint are presented in the paper. It is verified that the joint is reliable under 1.3 times of the design load. The effect of ring stiffeners is also studied in this paper.
Applications of Grey System Theory to Construction Control of Cable-Stayed Bridge
Authors: Wu Fang Wen , Xue Cheng Feng
Published: December 2010

Based on the grey system theory, and combined with the construction features of cable-stayed bridges and construction control method, the paper takes the cable-stayed bridge under construction as the interferential grey technology system with physical prototype and analyzes the random process as grey process in line with grey system theory. The grey model is established by the initialize heights of main girder and cables’ tension as two control inputs of system during the construction of the cable-stayed bridge. Through the feedback information and rectifying the grey model, the initialize heights of main girder and the cable force of next construction stage are predicted in order to control the bridge configuration and cable tension successfully.
Research on the Unloading Process of Long-Span Steel Roof and the Design of Temporary Bracing Structure
Authors: Shao Jian Hua , Wang Zai Hui , Tao Guang Ya
Published: December 2010

Unloading is a complicated process that the load-carrying condition of main structure is gradually transferred and the internal force is redistributed, and so the exact numerical simulation applied on the unloading process is crucially important. The steel roof composed of the space tubular truss with the long-span and cantilevered structure for the Helan Shan stadium at Yinchuan city in Ningxia Hui autonomous region is taken as an analytical example and the finite element analysis software SAP2000 is used to simulate the unloading process during the steel construction. The computational model is established and the simulation method is provided for investigating the detailed unloading process of steel roof. The load-carrying characteristic of every bracing point acquired by the numerical simulation analysis is applied to analyze and evaluate the structural performance under two different comparable unloading cases and then an optimized unloading scheme is achieved from these two cases. The deformation of steel roof and stress ratio of steel member at each different unloading step during the whole unloading process are presented. Ultimately, based on the preferable unloading scheme, the temporary bracing structure is designed by using the maximum reaction of bracing points when unloading.
Trial Study on Methods of Damage Extent Identification Based on Wavelet Transform of Strain Signal
Authors: Fan Jin , Liu Hong Po
Published: December 2010

Wavelet transform of strain signal can be used in the damage relative damage extent identification. The proposed method is validated by trial on a simply supported steel beam. And meanwhile the relative damage extent can be identified by drawing the curve of the maximum modulus of the wavelet coefficient and damage extent.
Monitoring for Large Cross-Section CFSTs of a Super High-Rise Building with Piezoceramic Actuators and Sensors
Authors: Huang Qing , Xu Bin , Li Bing , Song Gang Bing , Teng Jun
Published: December 2010

As a typical composite structural type, concrete-Filled Steel Tubes (CFSTs) have been widely employed in civil engineering structures, especially in super high-rise buildings because of their enhanced load-carrying capacity and ductility. The uniformity and quality of the on-site cast concrete within the tube and the interface bonding performance between the steel tube and the concrete have received extensive attention. In this paper, Piezoelectric ceramic materials, such as Lead Zirconate Titanate (PZT) and a kind of functional smart aggregate (SA) based on PZT together are employed to evaluate the concrete quality and the bonding performance of CFST columns of a super high-rise building with a design height over 400 meters and with large cross-section CFST columns. Based on the wavelet packet analysis on the measurements of the PZT sensors, results show that no obvious damage and defect is detected and the concrete qualify and the interface of large cross-section CFST columns of this super high-rise building are in good condition. The proposed monitoring technology has great potential to be applied to practical engineering.
Experimental Study on Temperature Fields of Dumbbell-Shape Section of CFST Arch Rib and its Effects
Authors: Yang Bin , Huang Jin Hua , Lin Chun Jiao , Wen Xing Kun , Liu Mao Jun
Published: December 2010

Based on the investigation of a constructing dumbbell-shaped concrete-filled steel arch bridge in Nanning, Guangxi, continuous on-site experimental researches on temperature field and its effects were carried out under the influence of hydration heat of concrete in the molding process of concrete-filled dumb-bell steel tubular arch bridge. On the basis of measured data, analysis on time-history law of temperature field and its effect under the impact of hydration heat of concrete of composite structure of concrete-filled steel tubes is made. The results reveal that temperature variation of hydration heat of the concrete within the steel tube is showed as follows: “Temperature up-continuous high temperature-temperature down-balance”. The structural temperature field, generated under the effect of hydration hea in the process of molding arch rib, is nonlinear temperature field. Concrete hydration temperature effect of crown section basically changes with temperature field simultaneously, while the residual strain of arch foot section is relatively large; hydration temperature effect of L/4 Section emerges peak fluctuations in concrete pouring process and finally levels off. Hydration temperature field of concrete has a great effect on crown section, which makes the steel tube continuously withstand the tension and compression alternatively, while the influence on the arch foot steel tube is not obvious. Surface strains of L/8, L/4, 3L/8 sections of steel tube transit from single-wave peak to dual-wave peak and finally turn into a single wave peak.
Acoustic Emission Monitoring and Fracture Process of Reinforced Concrete Beams Strengthened in Flexure with CFRP
Authors: Lee Young Oh , Yun Hyun Do , Seo Soo Yeon
Published: December 2010

This study was investigated the evolution of fracture damage of reinforced concrete (RC) beams strengthened in flexure with carbon fiber-reinforced polymer (CFRP) sheets or plates using acoustic emission (AE), and developed an AE monitoring strategy that can determine the structural integrity of RC beams strengthened by external bonding of CFRP sheets or plates. In this study, five beams were used, each with a cross sectional area of 200300 mm2 and length of 2,000 mm. Each specimen was simply supported and subjected to three-point loading. The AE signals were monitored during flexural testing of specimen using four sensors located on the side of each beam. The damage behavior and the microscopic fracture process of the RC beams strengthened with CFRP was evaluated using the AE parameters, such as AE duration time, event and amplitude. The two-dimensional AE source location was successful in measuring crack initiation and propagation in the RC beams strengthened with CFRP.
Characteristics of Multi-Storied Brick-and-Concrete Buildings Response to Blasting Vibration of Tunnel Excavation
Authors: Wang Hai Liang , Gao Tong Wei
Published: December 2010

According to fire station of Tuandao road along to the Yunnan road tunnel of Qingdao Cross-harbor Tunnel Guide Line Project, the blasting vibration test was carried on. This building is three-storied brick-and-concrete building. Then monitoring data of particle vibration velocity was analysised and researched. The results showed that there is magnifying effect of vertical vibration velocity on the roof of the building, but its value is lesser than particle vibration velocity of the first layer. Horizontal tangential vibration velocity was existed on the central of the building. However there was no magnifying effect of horizontal radial vibration velocity. And its value is decreased rapidly from the first layer to the second layer, and then other floors basically keep steady.
Posture Adjustment and Control Algorithm for Integral Synchronous Lifting of Bridge
Authors: Zhang Yu Qiang , Tang Xiu Hua , Chen Dong Hua , Ji Bo Hai
Published: December 2010

Based on the integral synchronous lifting project of main span for Nanlin Bridge, this paper mainly studies the causes which lead to difference of non-uniform displacement in the key parts of the lifting bridge and its impact to construction safety and calculates the maximum limit value of displacement difference. A displacement sensor network is applied to monitor the difference of non-uniform displacement, a posture adjustment and control algorithm based on average displacement is proposed to ensure construction safety during the synchronous lifting. The numerical simulation of synchronous lifting of Nanlin Bridge is conducted to verify the validity of posture adjustment and control algorithm, this paper provides important theoretical basis for the promotion and application of these results in practical projects.
Sensitivity Analysis of Continuous Web Plate Joint of Steel Beam to CFST Column Based on Correlation
Authors: Pan Jian Rong , Wang Zhan , Su Cheng
Published: December 2010

This paper deals with probabilistic sensitivity analysis for a semi-rigid joint of continuous web plate based on correlations analysis. Firstly, a numerical study was carried out by the software package ANSYS, the finite element analysis was validated compared with experimental results. Secondly, parameters sensitivity analysis was carried on by applying ANSYS Probabilistic Design Analysis. Considering the correlations in primary parameters, all random parameters are varied at the same time based on Monte Carlo simulation. An especial expression between geometric parameters and moment-rotation was discussed. Thirdly, the moment-rotation model of the joint was attained. The composite constant of the moment-rotation model is determined by partial derivative of any parameter from the model. It is concluded that the parameters of the model have notable physical meaning and the proposed model should be accurate and acceptable.
Experimental Research on Influence of Temperature on PZT-Based Health Monitoring for Smart Aggregates
Authors: Yu Jing , Zhu Hong Ping
Published: December 2010

Since piezoelectric materials exhibit strong temperature dependency. The change of temperature results in marked variation of the PZT transducer’s electric impedance signals, which may lead to misjudgment of the structural health condition. A experiment was implemented on smart aggregates with embedded PZT transducers under 35°C, 45°C and 55°C three working conditions, and found that the temperature had significant influence on the electric admittance signals of embedded PZT transducers. The peak magnitudes of the admittance curves changed and the curves shifted leftward. Then a temperature compensation technique was used to minimize the temperature effects.