bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Damping Properties of Fiber Reinforced Compositefor Stayed Cable
Authors: Du Yan Liang , Li Jian Zhi , Sun Bao Chen
Published: December 2010

Fiber reinforced vinyl ester composites and fiber reinforced epoxy composites were prepared by the pultrusion method. Due to the extensive application of fiber reinforced composites, the temperature spectrum and frequency spectrum of loss factor for the composite were tested using dynamic mechanical analysis (DMA) equipment. The damping properties and damping mechanism of the composite were investigated and discussed at different temperatures and frequencies. The result indicates that the loss factor of the composites is increasing with the increase of the frequency from 0.1Hz to 2 Hz and decreasing with the decrease of the temperature from -20°C to 60°C. The loss factor of the carbon fiber composite is higher than that of the glass fiber for the same matrix. The loss factor of the vinyl ester composite is higher than that of the epoxy composite for the same fiber.
Dynamic Test Signal Analysis and Modal Parameters Identification of High-Pier Long-Span Rail Bridge Based on HHT
Authors: Qin Shi Qiang , Pu Qian Hui , Shi Zhou
Published: December 2010

Dynamic loading test is exerted on a railway continuous beam bridge with a main span of 100m and a pier of 99m high, and dynamic responses are tested under natural excitation. Chebyshev digital filter is used to signal for low-pass filter according to the frequency distribution in FFT spectrum. A series of IMFs are obtained from the Hilbert-Huang Transform of a measured lateral displacement response, which shows: EMD is a self-adaptive signal analysis method that can effectively process non-stationary signal; IMFs can clearly show local features of complicated signal. Modal parameters of the bridge are identified based on HHT and Random Decrement Technique (RDT), the comparison of the identified results obtained from FFT, HHT-RDT and Finite Element Method is made, which show that HHT-RDT is an effective method to identify modal parameters of large bridge structures.
The Applied Research on TMD Control in Structures for Seismic Protection
Authors: Zhang Hong , Zhang Hong Yan
Published: December 2010

Based on the theoretical analysis of the dynamic parameters of multi-DOF complex structures, it is shown that the optimum TMD parameters under the harmonic base excitation are not the exact optimization for seismic protection, whose main reason is that the optimum damping ratio of TMD for seismic protection is obviously lower than that under the harmonic base excitation. In this paper, an effective TMD design method is developed to control the seismic responses of many-degree-of-freedom complex structures. The EI-Centro seismic wave is introduced as the excitations and the approach to determining the optimum TMD parameters for seismic protection is effectively solved. Then with the case to design the TMD of a series reactor, the optimum TMD parameters for seismic protection are obtained. Its result proves that the designed TMD is able to reduce the seismic responses of the series reactor significantly, and this approach can provide a reference for the TMD design for seismic protection of other multi-DOF structures.
Experimental Study of Buckling-Restrained Brace System with Pall-Typed Frictional Damper
Authors: Zhang Ji Gang , Han Jian , Deng Wen Yan
Published: December 2010

In view of general braces of Pall-typed frictional damper will produce additional axial forces on side column in frame, considering the buckling-restrained braces(BRB) to replace the general braces to make the braces action fully, it would not generate the growth of additional axial forces on side columns, to settle basis for BRBs’ application in Pall friction damping brace system. Because hysteresis behaviors of the Pall-typed friction damper are not affected by brace buckling forces, this paper puts forward that the braces use the ordinary steel plate replacing BRB core plate to do Pall-typed frictional damping brace experimental research, meanwhile considering the geometric nonlinearity the finite element simulation analyses are done for this brace system in ANSYS software. The experimental results and simulation results show that the Pall friction force and brace forces’ variation rule is almost the same, and the brace force is almost the same.
Static Finite Element Model Updating for Special-Shaped Bridge Based on Uniform Design Method
Authors: Gong Ya Feng , Liu Han Bing , Cheng Yong Chun , Wang Huan Li
Published: December 2010

The establishment of an effective finite element model (FEM) for the bridge structure is essential in the health monitoring system of urban grade separation bridge. It inevitably exist inconsistency of response between the FEM and practical structure due to various uncertain factors in the modeling and analysis procedure. Therefore the updating of FEM is necessary. A uniform design-based static model updating method is proposed in this paper, the allowable range of model parameters (the number is ) is divided into several levels (the number is ), the model updating method is transformed into a -factors and -levels test design. Several groups of combined parameters are selected to conduct test through finite element calculation based on the principle of uniform design method, and the optimal parameter group is obtained. This method is applied to the model updating of a complicated special-shaped urban grade separation bridge, and a perfect FEM with a good agreement with measured data is obtained. It confirms the feasibility and superiority of this method.
Finite Element Analysis for Unstiffened Overlapped CHS KK-Joints Welded in Different Ways
Authors: Wang Xiu Li , Yang Wen Wei , Zou Lei
Published: December 2010

The question whether hidden weld of unstiffened overlapped CHS (circular hollow sections) KK-joints is welded or un-welded is not clearly mentioned in China's steel structure design codes (GB50017-2003) .This paper mainly analyzes the influence of chord-to-brace diameter ratio β, diameter-to- ply ratio γ and brace-to-chord ply ratio τ to the ultimate bearing capacity of the joints with the hidden weld welded and un-welded. The influence of welded and un-welded hidden welds of the joints on hysteretic behavior under low frequency loading is analyzed , and hysteretic curve of the joints are obtained by the finite element software ANSYS. Side brace or opposite brace of the hidden weld of the joints has little influence on the failure modes and ultimate capacity of the joints. Hysteretic behavior of the joints with the hidden weld un-welded is much better than that of the welded.
Optimal Design of Microseismic Monitoring Networking and Error Analysis of Seismic Source Location for Rock Slope
Authors: Xu Nu Wen , Tang Chu Nan , Wu Si Hao , Li Gui Lin , Yang Ju Ying
Published: December 2010

For the purpose of getting a better understanding of failure mechanisms of rock fracturing due to construction perturbation inside the right rock slope of Dagangshan Hydropower Staion, a high precision microseimic monitoring system was installed and preliminary source location data have been investigated. The optimal design of microseimic monitoring network, especially the sensor array was investigated based on P method and Powell algorithm. The positioning accuracy of the system has been adjusted according to artificial fixed blasting tests. The testing results show that microseismic source location error is less than 10 m in the scope of the sensor array, which demonstrates the monitoring system deployed at the right slope has a high positioning accuracy. Signals from 112 microseismic events with moment magnitude ranging from -1.8 to -0.4 were recorded during its 2-month monitoring period. The cluster distribution of microseismic events can reflect directly the construction progresses such as the concentration of microseismicity inside the drainage tunnel at 1081 m level. The present study have significantly improved the understanding of the characteristics of the failure associated with excavation inside the rock slope, and will greatly benefit the potential sliding areas prediction and support of hazards in the phase of construction in future.
Parametric Analysis on Flexural Capacity of Flange-Plate Connections Considering Prying Force
Authors: Wang Yuan Qing , Zong Liang , Shi Yong Jiu
Published: December 2010

Within construction industry developing rapidly in domestic, long span buildings and high-rise buildings emerge in endlessly. Steel tubular structures are increasingly widely used for its unique advantages. Thanks to the situation, flange-plate connections become more and more popular as an important solution of splicing steel tubular structures. The connections provide easy and fast installation，nice shape, simple constitution for tubular structures without the need for welding. Typical loading situations include axial tension force and moment for flange-plate connections. The loading capacity under axial tension was studied by many scholars. Unfortunately, study on flexural capacity of flange-plate connections is limited. This situation limits the generalization of the nice connections. As can be seen from the review on flange-plate connections, there is no doubt that doing research on flexural capacity of flange-plate connections is necessary. Previous studies on axial loading capacity of flange-plate connections can provide helpful options of research for this work. One of the options is to observe the prying forces caused by flange-plates’ deformation, for prying is an important influencing factor on axial loading capacity of flange-plate connections which can reduce capacity of the connection. It is same as axial loading case that prying forces exists in the tensile region of flange-plate connections under bending moment, and they should be paid attention because they can reduce the flexural capacity of the connections with no doubt. This paper addresses on four basic kinds of flange-plate connection’s flexural capacity and is developed by means of finite element method with finite element program ANSYS. Related FE models are established and checked compared with experimental results. Based on the reliable FE models, the subsequent analysis especially studies on the effect factors of prying force in the tensile region of connection in the tensile region of connection. The corresponding parametric analysis is developed, including the thickness of flange-plate, the ratio of outer and inner diameter of flange-plate, material property of bolts, etc. Finally the key effect factors are found. The conclusions from this paper can provide references for Engineering Design.
Structural Optimization of Offshore Jacket Platform Based on ANSYS
Authors: Yan Qing Zhi , Zhang Zhan , Cui Liang , Wang Yan Hua
Published: December 2010

Offshore Jacket Platform is a very important infrastructure in the offshore oil exploration and exploitation. In order to make it more economical, designers should do Structural Optimization to it. This paper do Structural Optimization to Offshore Jacket Platform, and provide reference for the using of ANSYS in the Structural Optimization of Offshore Jacket Platform.
Influence of Cover Porosity on Steel Corrosion in Cement-Based Materials
Authors: Shi Jin Jie , Sun Wei
Published: December 2010

A detailed investigation has been carried out to clarify the effect of porosity on steel corrosion in cement-based materials. Corrosion behaviours of steel were studied by means of corrosion potential, linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS), while the porosity of cover zone cement-based materials were investigated by evaporative water method (EWM) and mercury intrusion porosimetry (MIP). The results highlight that the corrosion parameters of steel are strongly related with porosity of cement-based materials. A linear relationship between porosity and corrosion rate of steel has been established which is in good agreement with the principle that the diffusion of chloride ions through porous cementitious materials may accelerate the anodic reaction of steel corrosion as well as oxygen diffusion for the cathodic reaction simultaneously.
Behavior of Different Corrosion Ratio RC Beams under Fatigue and Monotonic Loads
Authors: Wang Lei , Yu Ai Ping , Liu Bao Chen
Published: December 2010

This paper present results and discussions on an experiment study on the impact of corrosion ratio to the RC beams under fatigue and monotonic loads. Seven reinforced beams with the same steel type, concrete cover, steel diameter and ratio were test. The effect of corrosion ratio on flexural stiffness of these RC beams was discussed. Based on fatigue and monotonic test for these beams, the most investigated parameters in this experimental study were distortion, stress distribution, ultimate load of corroded reinforced concrete beams. The results indicate that the effect of corrosion ratio on flexural stiffness of RC beams is very obviously, curvatures of corroded beams increase monotonically with degree of corrosion. Fatigue loading has great impact on the performance of corroded RC beams; it can reduce the ultimate strength and ductility of the beams significantly as corrosion ratio increase.
Rational Calculation Model of Interlayer Separation of Complex Roof in Deep Coal Tunnel
Authors: Wu De Yi , Wang Ai Lang , Wen Guang Kun
Published: December 2010

In order to reasonably analyze interlayer separation of complex roof in deep coal tunnel, the rational calculation model was chosen and distribution of normal stress, shear stress and interlayer separation of construction surface in elastic and plastic conditions were analyzed in different original rock stress. In order to analyze varying interlayer separation with time, rational creep model was chosen and the results were drawn that plastic deformation of complex roof had obvious influence on interlayer separation and numerical simulation agreed well with the actual varying interlayer separation with time by burger creep viscoplasticity model to analyze creep characters of complex roof.
The Fractal Character of Corrosion Steel Surface
Authors: Kong Zheng Yi , Xu Shan Hua
Published: December 2010

In this paper, the corrosion specimens are obtained by ways of constant temperature and humidity ,and the size of corrosion pits is detected by roughness tester. So surface characterization of steel corrosion is researched by fractal theory and it has been proved by structure function that it has the fractal character. It find that the fractal dimension is inherent and it will not change with the sample length. The result indicates that the fractal dimension is decreasing with the corrosion rate increasing. so it will help to solve the difficult of safety assessment for In-service steel structure.
Probabilistic Analysis of Corrosion-Induced Resistance Degradation of Reinforced Concrete Bridge Beam under Incomplete Information
Authors: Wang Lei , Ma Ya Fei , Zhang Jian Ren
Published: December 2010

The influencing information of structural resistance cannot be exactly inspected due to limitation of the experimental means, time and space. The study must be conducted by incomplete information and the uncertainty is enhanced. The uncertainty consists of fuzziness, randomness, and faultiness of knowledge. The faultiness of knowledge is the weak uncertainty, and can be incorporated into fuzziness and randomness. A novel probabilistic analysis method of corrosion-induced resistance degradation subject to fuzziness and randomness is developed in this paper. The reinforcing bar corrosion is induced by chloride ion attack in reinforced concrete (RC) bridge. The relationship between steel area corrosion rate and yield strength is presented based on the experimental investigation on mechanical property of corroded reinforcement. The fuzzy time-variant probabilistic analysis of resistance degradation is illustrated by an example problem of RC bridge beam. The result can be used to time-variant reliability-based evaluation for reinforced concrete.
The Effects of Carbonation on Damping Capacity of Reinforced Concrete Materials
Authors: Liu Tie Jun , Sui Li Li , Zou Du Jian
Published: December 2010

Carbonation of cementitious materials results in a reduction of the pH value which makes the material less alkaline and leads to unsightly spalling on structures. In this paper, the experimental investigation on damping capacity of reinforced concrete materials and members with carbonization at different ages was carried out by the method of 3-point bending beam damping measurement and cantilever beam free vibration respectively. The experimental results show that loss tangent and loss modulus were all decreased by carbonization. It shows that the damping capacity is decreased by carbonation corrosions with the carbonation time increase. It is indicated that the effects of carbonation-induced corrosion on the damping capacity for engineering materials and structures are absolutely essential.
Durability of E-Glass Fiber Reinforced Polymer Subjected to Freeze-Thaw Cycle and Sustained Load
Authors: Li Shan , Lu Yi Yan , Ren Hui Tao
Published: December 2010

Strengthening concrete structure with E-glass fiber reinforced polymer (GFRP) is gaining more popularity, mainly due to their superior mechanical properties. However, there is insufficient information on environmental durability of glass fiber reinforced polymer, especially in harsh environmental conditions combined with sustained load. In this paper, the durability of an E-glass/ composite material under freeze-thaw cycle either in an unstressed state or loaded in about 30% of the initial ultimate load are investigated. The residual tensile properties of the GFRP are studied after coupled action of freeze-thaw cycle and sustained load. The results indicate that the single action of freeze-thaw cycle reduces the ultimate tensile strength and strain of the GFRP, and the coupled action of sustained load and freeze-thaw cycle further reduces the ultimate strength and strain of the GFRP.
Seismic Assessment of RC Structures in Service Affected by Reinforcement Corrosion
Authors: Zou Du Jian , Liu Tie Jun , Lv Hai Xia , Teng Jun
Published: December 2010

The safety and serviceability of RC structures are time-dependent due to degradation phenomena, therefore assessing the fulfillment of required levels of safety and serviceability up to the end of the design working life of the structure is particular important. Among the most frequent environmental attacks affecting RC structures, reinforcement corrosion is considered the most dangerous source of degradation, which may occur only after depassivation due to carbonation of concrete cover, penetration of chloride ions, or a combination of both. In this paper, the effects of rebars corrosion on seismic response of RC structures were presented. A case study was analysed using time history analyses, in sound as well as damaged conditions, assuming a moderate corrosive attack. The outcomes were discussed in terms of displacement time history curves and acceleration time history curves. In addition, the interstory drift obtained form time history analyses was compared and discussed with the limit value provided by Code for seismic design of building.
Study on Permeability of Concrete under Sustaining Tension
Authors: Ma Li Guo , Zhang Yun Sheng , Song Lu Guang
Published: December 2010

An experimental device which provided uniaxial sustaining tension stress to concrete was especially designed with pressed spring. The accelerated, steady state chloride migration experimental method was used to test the permeability of concrete under tension resulting from designed device. Concrete with two mixture proportions was tested to get chloride diffusion coefficient under different tension stress. Mathematics models were built to show the change of chloride diffusivity coefficient of concrete under tension.
Study on Statistical Parameters of Resistance of Steel Highway Bridge Reliability Design in China
Authors: Li Kun
Published: December 2010

The coming national specification for steel highway bridge will adopt the design method of probability limit state based on the structure reliability theory. Then the statistical parameters of loads and resistance play a key role in this method. Based on the extensive survey and investigation on site, the parameters of resistance are calculated in the study. In the work, three aspects of resistance’s uncertainty which are the uncertainty of materials properties, geometric parameters of members and calculation model are analyzed respectively. Then, the statistical parameters of five typical members of two commonly used steels—Q235q and Q345qD—in steel highway bridges are calculated. The recommended statistical parameters of resistance of steel highway bridge can be a reference for the new specification.
Condition Evaluation of Existing Long-Span Bridges Using Fuzzy Based Analytic Hierarchy Process
Authors: Deng Jun , Li Jian , Fang Xiao Yue
Published: December 2010

The existing long-span bridges deteriorate with time due to fatigue, overloading, corrosion and environmental effects. To date, condition evaluation of the existing long-span bridges is important to carrying out the activities related to maintenance, rehabilitation and replacement of bridges. In this paper, a methodology was developed to evaluate the condition of the existing long-span bridges. The analytic hierarchy process was combined with the fuzzy synthesis. A procedure is given for condition rating of the existing long-span bridges as well. A bridge as the example is evaluated by this method and the results show that the damage of the bridge is marginal, which is same as the conclusion obtained from the traditional methods.
Fatigue Analysis of the Asphalt Mixture Beam Using Damage Evolution Equations
Authors: Han Ding , Zhan Bing Gen , Huang Xiao Ming
Published: December 2010

Damage evolution equations of asphalt mixture specimen beams were analyzed using the fracture toughness index and the ultimate tension strain index, respectively. The fracture toughness of the asphalt mixture was calculated by FEM. Damage evolution equations controlled apart by the stress and the strain were given. Their coefficients were back-calculated using partial fatigue tests data. The fully coupled stress-damage method and the fully coupled strain-damage method were used. The life prediction precision of each equation was verified by residual fatigue tests data. The results show that FEM is effective to calculate the fracture toughness of the asphalt mixture. Two damage evolution equations have better life prediction abilities comparing with the S-N equation used usually.
Damage Analysis of Mianzhu School Buildings in Wenchuan Earthquake
Authors: Li Xing Kui
Published: December 2010

Introduced after the Wenchuan earthquake, the situation of teaching buildings collapsed, buildings destroyed by the actual picture of the location and characteristics of some typical building damage, building damage arising described several major reasons put forward the views of housing and construction reinforcement, stress the seismic design and the importance of project quality management.
Study on Operating Vehicle Load Limit of Sub-Health Bridge
Authors: Zhang Jun Ping , Liu Ai Rong , Wu Gang , Zeng Ke
Published: December 2010

Depending on the actual service condition of sub-health bridge, the following investigation is carried out: 1)The concept of damage limit state is proposed, from which the subject of the serviceability carrying capacity is revealed, then the evaluation path of serviceability carrying capacity of sub-health beam is given.2) The difference between the reliability of sub-health bridge and new bridge is analyzed, consequently, the problem about reasonable limit vehicle load is solved preliminarily in theory.
Research on the Whole Stability of Axially Compression Member of Cold-Formed Thin-Walled Steel Sections in the Effect of Initial Imperfection
Authors: Liu Hua Chen , Guo Yao Jie
Published: December 2010

In calculating the reliable capacity of carrying load of cold-formed thin-walled steel members, there has not yet been a proper method which directly takes into account the impact of the residual stress. Through the research of residual stress, models close to the actual situation are established. Based on the ultimate load criterion, considering both cold-formed residual stress and initial out-of-straightness, the whole stability of axially loaded compression member of cold-formed thin-walled crimping angle steel and channel steel are analyzed using FEM. Based on a lot of FEA numerical results obtained, the φ-λ curves of different kinds of sections and size are obtained. Finally, φ-λ curve that reflects the fact can be obtained. By comparing the curve with the code and results of experience, it is proposed that the stability coefficient φ of small slenderness member of the code should be increased appropriately.
Application of Energy Dissipation Technology to C-category Frame Structure of School Buildings for Seismic Retrofit of Increasing Precautionary Intensity
Authors: Weng Da Gen , Zhang Chao , Lu Xi Lin
Published: December 2010

In the Ms8.0 Wenchuan earthquake on 12th May 2008, a large number of primary and secondary school buildings were seriously damaged. Therefore, considerable attentions have been paid to earthquake resistance capacity of school facilities and some relevant national codes in China have been updated after earthquake. Recently, many approaches to seismic retrofit of school buildings have been proposed and applied. The focus of this paper is on application of energy dissipation technology to C-category frame structure of school buildings retrofitting, with the objective of increasing one grade of precautionary intensity, while the C-category buildings are designed in conformity with China’s code for seismic design of buildings (GB 50011-2001). Since the seismic precautionary classification of school buildings has been changed from standard precautionary category to major precautionary category, the structural ductility requirements are stricter with the increase of seismic precautionary intensity. Thus, this paper presents the retrofitting difficulties in C-category frame structure of school buildings for the restriction of ductility requirements, and also explores how to apply energy dissipation technology to seismic retrofit of such buildings for achieving expected retrofitting objective and reducing heavy strengthening tasks. In the end, a retrofitting example of C-category frame structure of school building is cited to demonstrate the feasibility of energy-dissipating retrofit method. The analysis results indicate that energy dissipation technology can be well applied to C-category frame structure of school buildings retrofitting for increasing one grade of precautionary intensity.
The Rehabilitation of Pile Foundation of a Concrete Continous Bridge in Guangzhou City
Authors: Jiang Hai Bo , Yang Ling Ming , He Ai De
Published: December 2010

Due to heavier traffic loads, progressive structural age, and corrosion of steel reinforcement, there has been an increasing need to strengthen the pile foundation of concrete bridges. In this paper, the damages and deteriorations on a concrete bridge in Guangzhou City are described in details, which causes are discussed also. The rehabilitation method by prestressed cushion cap is proposed based on the finite element analysis. The rehabilitation scheme is verified by the result of calculation, and the practice of strengthening project proves that this method is technical feasibility, construction convenience and lower economic cost. The research results can be provided as a reference for the similar bridges.
Research of Stress Concentration and Retrofitted Methods for Orthotropic Steel Bridge Decks
Authors: Zhang Yan Ling , Zhang Yun Gang , Li Yun Sheng
Published: December 2010

In this paper, the stress distribution of the orthotropic steel bridge deck in a suspend bridge under local wheel load is analyzed. Some retrofitted methods are introduced, two of which are studied. One is using the concrete paving layer (CPL), and the other is using the sandwich plate system (SPS) to strengthen the orthotropic steel bridge deck. Local finite element models are established by ANSYS; stress distribution of bridge deck is calculated under the designed vehicle load before and after the deck retrofitted by the CPL or the SPS, and the results are compared with each other. The analysis results indicate that, under wheel pressure load, the orthotropic steel deck appears stress concentration; after the deck was retrofitted no matter by the CPL or the SPS, all the stress peaks decrease obviously, and the fatigue resistance of the orthotropic steel deck increases, which indicate that the two methods are effective to retrofit the orthotropic steel bridge deck. Using the CPL method can lead to lower stress concentration than that of using the SPS method, but the concrete paving layer is easy to crack, so, high performance concrete with high tension strength is needed.
Reseach on Flexural Behavior of Reinforced Concrete Beams Strengthened with Prestressed Near Surface Mounted CFRP Tendons
Authors: Ding Ya Hong , Ma Yan Jie
Published: December 2010

The effectiveness of strengthening reinforced concrete (RC) beams with prestressed near- surface mounted (NSM) carbon fiber reinforced polymer (CFRP) rods has been investigated. The RC beams are tested under monotonic loading. The stressing process, failure capacity, flexural capaticy, displacement ductility and deformation are systematically studied. The text results show that the new strengthening technique with prestressed NSM CFRP rods can enhance the first-crack load, steel-yielding load of beams compared to the control beam. It is worth noting that the prestress can limit the crack width all the way up to failure, reduce the midpoint deflection, and improve the service performance of the strengthened beams. The strengthening method offers an alternative way to existing strengthening method. The results provide a reference for engineering application.
Out-of-Plane Behavior of Masonry Walls Strengthened with Ferrocement
Authors: Chen Sheng Ping
Published: December 2010

Un-reinforced masonry (URM) structures may fail and collapse under out-of-plane loads generated by seismic forces or explosions. Adding a ferrocement overlay onto the URM walls is an effective solution in increasing the ultimate load capacity and ductility. This paper deals with the numerical and experimental studies on the out-of-plane behavior of un-reinforced masonry walls strengthened with ferrocement. The material parameters considered are the volume fraction of reinforcement and the loading area. A numerical model was proposed to simulate the experimental results. The employed material model for masonry wall is based on the theory of Drucker-Prager plasticity taking into account the tension softening behavior, while the ferrocement is modeled as a composite material with linear strain hardening followed by ideal plasticity. The proposed model simulates the load-deflection behavior of the strengthened wall well.
Creep Properties of CFRP-Steel Composites Subjected to Tensile Loads
Authors: Lu Yi Yan , Zhang Xue Peng , Tang Zhi Yu
Published: December 2010

Strengthening by CFRP sticking to steel plates can exploit advantages of the two materials. The viscoelastic nature of FRP composites make it imperative that the creep behavior of the composite material should be taken into account for the analysis and design of any strengthening structure. In this paper, a creep experiment of a CFRP-steel composite under different stress levels has been introduced. The failure types, average yield load, ultimate loads, and initial longitudinal elastic modulus of the composite specimens were investigated through the short-term tests. Material coupons were subject to axial tensile load at various stress levels for time duration up to 500 hours in the long-term tests, and the results indicate that the strain increase with time and the ultimate creep strain increase with the increase of the initial strain. For the evaluation of the viscoelastic behavior of the composite material, the model developed by Findley was adopted. The agreement of the model results with the experimental data indicates this medel could be used to estimate the creep effectively at engineering analyses.
Experimental Research on the New Method of Complex Reinforcement for Steel Beam
Authors: Jia Lian Guang , Hou Li Zhe
Published: December 2010

A new type of complex reinforcement method for steel structure seldom used in pratical engineering mainly due to lack of theoretic and experimental support. The experiment with this method for H-section steel beams and the results of that are introduced in this paper. The mechanical properties of the steel and CFRP material are given. The carrying capacity and the load-displacemengt curves of each specimen beams are obtained as well as the stress and strain of every feature points on the middle cross section of the beams. The results may provided reference for practical engineering.
Experimental Study on Flexural Performances of Concrete Beams Strengthened with Near-Surface Mounted (NSM) FRP Reinforcement
Authors: Sui Li Li , Liu Tie Jun , Xing Feng , Fu Yu Xiang
Published: December 2010

This paper illustrates the results of an experimental study on the bending performance of concrete beams strengthened with near-surface mounted (NSM) FRP reinforcement. The critical parameter of the embedded length of NSM-FRP plates was investigated in particularly. The test results indicated that NSM-FRP reinforcement can significantly improve the strength and crack resistance capacity of the concrete beam, reducing the size of cracks. The embedded length of the NSM-FRP plate has distinct influence on the cracking and bending capacity, the flexural stiffness, and the crack developments of the concrete beam. As the embedded length increased, the bending capacity and the flexural stiffness increased correspondingly and the crack developed more intensively.
Reinforcement Method with CFRP in Longmen Grottoes Plank Way Slab
Authors: Gao Xiao Juan , Li Yue Hui , Li Jian Hou
Published: December 2010

Longmen Grottoes is the famous cultural heritage. Many factors should be considered in reinforcement project of the plank way slab. Considering the characteristics of the tourist area, many reinforcement schemes are put forward, at last, the method with CFRP sheet is selected to reinforce the plank way slab. The reinforcement effect shows that this method increases very little weight of the structural members. The appearance of the reinforced members are harmonious to the surrounding environment.
Using the Explicit Dynamic Method to Simulate Pile Dynamical Driving Process
Authors: Lv Jian Bing , Fu He Lin , Li Hua Zhi , Liu Zhe
Published: December 2010

The dynamic pile driving process is so complex that till now the analysis on the process had been focusing on the filed test or laboratory test. However, the past study about the dynamic process is a time consuming one; with the computational method development, the numerical simulation on this process is possible. In this paper, explicit dynamical analysis method is adopted, the pile is simulated using the elastic solid element, two computational cases are considered and finally the pile driving process dynamical stress is studied.
Behavior of Large-Scale Circular and Square RC Columns Confined with Carbon Fiber-Reinforced Polymer under Uniaxial Compression
Authors: Wang Zhen Yu , Wang Dai Yu , Lu Da Gang
Published: December 2010

Most experimental studies concerning the stress-strain behavior of concrete columns confined with carbon fiber-reinforced polymer (CFRP) focused on plain concrete columns with small section. In this study, 34 concrete columns with large-scale circular and square cross section confined with CFRP were tested under axial compression to investigate the influence of sectional dimensions, internal steel reinforcement and thickness of CFRP jackets on the stress-strain behaviors. Test results indicated that the confinement of CFRP resulted in significant increase in axial stress and strain for circular RC columns, while remarkable enhancement in axial strain but slightly in axial stress for square RC columns. The stress-strain responses of CFRP-confined square RC columns were significantly influenced by sectional dimensions and internal transverse reinforcement. The typical confinement ratio, which is obtained from studies on CFRP-confined unreinforced concrete columns with small cross sections, was not applicable for the case of large-scale square RC columns.
Meso-Level Numerical Study on Different Type of Fiber Reinforced Concrete
Authors: Zhang Ya Fang , Liu Hao , Chen Jiang Ping
Published: December 2010

To investigate failure mechanism and toughening features of fiber reinforced concrete (FRC) with different reinforced fibers, meso-level numerical simulations have been conducted on FRCs incorporated with steel, glass and polypropylene fibers, respectively (which were named as SFRC, PPRC and GRC). The complete failure process of crack initiation, coalescence and development, interaction and final break have been simulated. By analyzing the failure patterns of specimens, also the spatial and temporal distribution of acoustic emission and loading - step curves, it can be concluded that both peak strength and toughness of SFRC and GRC can be greatly improved. However, for PRC, the improvement of peak strength is little while its toughness can be enhanced significantly.
Simulation Study on Concrete Structure Bonding with Steel Plate
Authors: Wang Yan Lin , Wu Lan Ying , Wang Ling Gang
Published: December 2010

The building structure reinforcement simulation system is very necessary for the rapid development of the building reinforcement industry, in this paper, the feasibility of the simulation on concrete structure bonding with steel plate was analyzed, and the influence of deformation and stress of concrete beam was studied by the thickness of steel plate and bonding layer. The research results show that the cracking load of the original concrete beam model is 8.712 KN, the limit load is 8.92 KN, and the midpoint displacement is 0.4443 mm; when the thickness of steel plate is 4 mm, the limit load is 11.579 KN, comparing it to the 8.92 KN of the original concrete beam model, the bearing capacity can be improved to 32.91%; The maximum adhesion stress at the end of the bonding layer increases first and then decreases as the thickness of the bonding layer increases, the ratio between the maximum adhesion stress and the minimum adhesion stress increases first and then decreases as the thickness of the bonding layer increases.
Study on Field Detection and Monitoring Test for a Project of Large Area Soft Foundation Treatment
Authors: Zhang Rong Lan
Published: December 2010

To accord with the requirements of large area soft foundation treatment project, did the construction field monitoring and detection test including surface subsidence, pore water pressure, deep horizontal displacement, cone penetration test, vane shear test, and so on, make an effective and timely assessment with the construction quality and the reinforcement effect of foundation treatment project.
Energy-Saving System Analysis about the Exterior Building Enclosures of Wenyuan Building
Authors: Feng Qian
Published: December 2010

Energy conservation in Building is becoming the most important topic for energy conservation and environmental conservation. In order to explain the relationship between building exterior-protected construction and energy conservation .We choose Wenyuan Building as an example, using DOE program and Air-Pak software to study, to prove the importance of exterior-protected construction to building conservation.
Experimental Research on Aseismic Strengthening of R.C Cross-Shaped Columns
Authors: Tian Wen Ling , Dong Hao , Jie Niu
Published: December 2010

Using the method of sticking steel plates and CFRP, 2 R.C. cross-shaped columns are strengthened. One using steel pastes, another using complex strengthening by steel plates and CFRP. 2 strengthened columns and an unstrengthened column was carried out aseismic test. Study showed that pasting steel strengthening; carrying capacity of the cross-shaped column has been significantly improved; while the method of complex strengthening, carrying capacity and ductility of the cross-shaped column were significantly improved.
On-Site Test Study of RC Slabs Strengthened with CFRP and BFRP
Authors: Xu Xin Jian , Li Li Juan , Zhou Wen Chao , Min Ming , Liu Feng
Published: December 2010

This paper presented the on-site test results on two-way RC slabs with and without FRP-strengthening. Two slabs strengthened with BFRP, one slab strengthened with CFRP and one slab without strengthening were tested on a practical engineering structure being repaired. The effects of different load cases on mid-span deflection, distribution of stresses around the steel bars at the top and bottom of slabs were analyzed.
Lateral Force Demand of Essential Equipments in Hospital Buildings for Earthquakes
Authors: Huang Chao Hsun , Tuan Yung Ting Alex , Huang Chun Ying
Published: December 2010

To deliver the badly need medical services for the victims, major regional hospitals are expected to remain operational after an earthquake. In order to provide continuing services, these hospitals not only have to secure the structural safety of the buildings, but need to ensure the functionality of essential equipments. In this study, a finite element analysis was performed on equipments attached in a series of reference buildings to examine the structural demand of hospital equipments during an earthquake. It was found out that the current code provides a good estimation for equipment with a short period of vibration. For those with longer periods, however, the component amplification factor should be obtained from the design spectrum.
Earthquake Impact Analyses on Slopes Using Finite Element and Limit Equilibrium Methods
Authors: Ong Yu Hwang , Kasa Anuar , Chik Zamri , Mohd Raihan Taha
Published: December 2010

The objective of this research is to determine factor of safety for various cut slopes under the influence of earthquake activity. Finite element method was used to generate initial static stress condition and run dynamic analyses of the cut slopes. Factor of safety was then calculated using limit equilibrium method. Both sand and clay were analyzed in this study. The results show that steep slopes with initial safety factor of 1.5 are capable to sustain earthquake magnitude of 0.25g due to high shear strength of the soil. However, slopes with friction angle less than 21º for sand and cohesion value less than 38 kPa for clay are not stable. This shows that earthquake loading should be considered in the design of cut slopes in Malaysia.
Partially Double-Layered Dome Structure Linear and Nonlinear Buckling Analysis
Authors: Lv Jian Bing , Fu He Lin , Li Yang , Liu Zhe
Published: December 2010

Space steel structure stability has been a focused problem in the engineering field, in the past the study mainly concentrated on the single layer dome structure stability and elastic stability analysis, but with the structure shape complex, new type structure emerges continually, it needs more accurate stability analysis method. In this paper the linear and nonlinear buckling theory and analysis method are introduced firstly, and then a new type steel space structure with partially double layer dome structure is chosen as the computational model. The structure self vibration mode, linear buckling analysis and nonlinear buckling process and buckling characteristics are studied by the FEM commercial code ANSYS; the nonlinear load-deflection curves at the different points are gotten and some conclusions about this kind of structure are drawn.
The Isolation Effect Analysis of Base and Story Isolation System in Vertical Seismic Action
Authors: Duan Shao Wei , Tao Xiao Wei , Liu Hai Kuan
Published: December 2010

Through establishing single material point model of base isolation system and two material points model of story isolation system in vertical earthquake, the isolation effect of base and story isolation system in vertical earthquake are studied. Results show that two kinds of isolation systems cannot effectively keep apart the vertical seismic action, and the effect is amplified on the contrary, especially the position of isolation layers in story structures affect the amplification effect. Compared with the base and story isolation structures, while using the same isolation device, the former is better than the latter in isolating vertical seismic action.
Seismic Behavior Analysis and Seismic Strengthening of Corner Joints without Seismic Details
Authors: Zhang Hai Yan , Duan Jing , Chen Xiao Mei
Published: December 2010

Seismic performance of corner joints without seismic details was analyzed by software ABAQUS, the results indicated that the reinforcement ration of the girders has great effects on the failure process and seismic behavior of corner joints. Beam Haunch Method was used to strengthen these joints, and then finite element analysis was conducted for the joints with unidirectional haunched beam (UHB)and bidirectional haunched beams(BHB). It was found that the bearing capacity of joints was significantly improved but the ultimate displacement and ductility factor were slightly affected by the haunch strengthening. The strengthening effect of bidirectional haunch was obviously superior to that of unidirectional haunch.
Modeling of Hysteretic Damper in Three-Story Steel Frame Subjected to Earthquake Load
Authors: Masoomi Mohammad Saeed , Osman Siti Aminah , Shojaeipour Shahed
Published: December 2010

This paper presents the nonlinear time-history and response spectrum analysis for a three-story steel moment frame and a braced frame by hysteretic damper against earthquake load which analyzed by SAP2000 software. The mentioned frames were analyzed by Eigenvalue method for linear analysis and Ritz-vector method for nonlinear analysis. Simulation results were presented as a time-displacement graph based on dynamic analysis, the dynamic base shear force is also calculated.
An Experimental Study on Seismic Performance of Reinforced Masonry Structure with Small-Sized Concrete Hollow Blocks
Authors: Wang Hai Biao , Guo Xun , Li Bao Kuan , Yang Hai Xu
Published: December 2010

This paper focuses on the analysis of dynamic characteristics of structural systems, maximum response of acceleration and maximum inter-story displacement angle etc. so as to study the seismic performance, yielding mechanism and seismic resistance capacity of the structure under the circumstance of constructional measures of seismic intensity VII through an earthquake shake table test on a model of a six-story reinforced masonry structure with small-sized concrete hollow blocks. In view of the whole test process, the integral deformation of the reinforced masonry structural model under the influence of seismic vibration is predominantly bending deformation. While inputting different earthquake intensity, the transverse peak average of maximum input acceleration that can be sustained by the structure is lower than that of the vertical peak average. Meanwhile, transverse deformation is more severe than vertical deformation, indicating that vertical seismic resistance capacity is stronger than transverse seismic capacity. The test result shows that the effect of the constraint system consisted of ring beam, constructional column as well as horizontal tie reinforcement is quite obvious, the structure possesses comparatively strong resistance of failure under the influence of moderate and strong earthquakes, which can completely meet the requirement specified in the Seismic Codes, that is, standing erectly when it is subjected to great earthquakes in the area of seismic intensity VII. When the structure is subjected to rare earthquakes, it also possesses considerable seismic resistance capacity.