bluuebunny/crossref_metadata_2025 huggingface dataset:
Shrinkage Performance of Adherence of New Steel Fiber-Reinforced Concrete to Old Concrete
Authors: Cheng Hong Qiang , Gao Dan Ying
Published: December 2010

Shrinkage experiments were done to determine the influence of the volume fraction of steel fiber-reinforcement on the bonding behavior between new concrete and old concrete. The mechanics of the model of restricted shrinkage upon the adherence of new steel fiber reinforced concrete to old concrete are described. The results demonstrate that the difference of shrinkage between the new and the old concrete can been reduced by adding steel fiber to the new concrete. The decrease of shrinkage difference reduces the shrinkage force at the adhesive interface, which improves the adhesion of new concrete to old concrete and the magnitude of the decrease of shrinkage difference is correlated to the steel fiber volume fraction.
Research on Hysteretic Behavior of the Concrete Filled Square CFRP-Steel Tubular (S-CFRP-CFST) Beam-Columns (II): Experimental Results and Analysis
Authors: Che Yuan , Wang Qing Li , Shao Yong Bo , Zhang Xu
Published: December 2010

Based on analysis of the hysteretic experimental results of the concrete filled square CFRP-steel tubular (S-CFRP-CFST) beam-columns, it shows that the steel tube and the CFRP material can work concurrently both in longitudinal and transverse directions, the longitudinal strain and the transverse strain at a same point have opposite action. Additionally, the deflection curves of all the specimens are close to half sinusoidal shape. Analysis indicates that there is some strength degradation. The axial compression ratio and strengthening factor of the longitudinal CFRP can enhance the strength and the stiffness of the members and they can also delay the stiffness degradation. However, they will decrease the accumulated energy dissipation of the members. The axial compression ratio is beneficial to seismic behaviors to some extent.
Research on Hysteretic Behavior of the Concrete Filled Square CFRP-Steel Tubular (S-CFRP-CFST) Beam-Columns (I): Experimental Study
Authors: Che Yuan , Wang Qing Li , Shao Yong Bo , Mu Hai Tao
Published: December 2010

Overall 12 specimens were experimentally investigated in this paper to study the hysteretic behaviors of the concrete-filled square CFRP-steel tubular (S-CFRP-CFST) beam-columns. The test results indicated that CFRP can provide transverse confinement effect and longitudinal strengthening effect for the concrete filled square steel tubular (S-CFST) beam-columns effectively and the local buckling of the steel tube is deferred. The hysteretic load-deflection curves and the hysteretic moment-curvature curves at the mid-span of all the specimens are generally plump, and it shows these specimens have good hysteretic performance. In the later loading period, the load bearing capacity drops.
Bearing Behavior of Steel Foot Pipe in Tunnel on Soft Base
Authors: Wu Yi Min
Published: December 2010

Numerical simulations were conducted to investigate the bearing behaviour of steel foot pipe. Main mechanical affections occur at the lateral zone, and the maximal stress occurs at the lateral end of the pipe. With the increase of cross direction load, the maximal stress increases and exceeds the strength of material, and the pipe is pulled out. The influencing factors of bearing capacity of the steel foot pipe were studied. Some important results different from engineering experiences are as following: 1) to steel foot pipe that can not penetrate the soft base, its reasonable dip angle is very small for its low longitudinal bearing capacity; 2) steel pipe with diameter of 42mm is unsuitable for foot steel pipe because its low cross bearing capacity; 3) to a given geological condition and pipe parameter, the reasonable length of steel pipe is certain, extra longer pipes can’t obtain larger capacity; 4) surrounding rock near the support structure should be especially reinforced by drilling grouting holes along the whole steel pipe.
Numerical Analysis of Foundation Settlement for a Fifteen-Story Moving Building
Authors: Jia Qiang , Meng Xiao , Zhang Xin
Published: December 2010

Differential settlement of the new foundation was produced after the building monolithic moving was finished. The internal forces of the top building were changed due to the existence of the differential settlement and the original differential settlement, which affected structural safety. A three-dimensional finite element model was established based on the ANSYS program to attain the foundation settlement law of a fifteen-story moving building. Through calculation and comparation of the settlement values and differential settlement between slab foundation and pile foundation, the pile foundation was finally selected as the construction scheme. Simultaneously, numerical analysis of foundation differential settlement during the moving process was performed. The monitoring results were showen to be in reasonable agreement with the numerical analysis results.
Discussion and Method on Performance Based Seismic Design for Concrete-Filled Steel Tubular Structures
Authors: Wang Wen Da , Xia Xiu Li , Shi Yan Li
Published: December 2010

The theory of performance-based seismic design (PBSD) is the key issue for the modern earthquake engineering research. With comparison of the traditional prescriptive seismic design code based on the bearing capacity design, the PBSD method presents the specific performance object for the buildings. On the base of the background and development of the PBSD about reinforced concrete (RC) structures, some researches and design approaches of PBSD were proposed for the concrete-filled steel tubular (CFST) structures based on the research results on PBSD of RC structures and the mechanical behavior of CFST structures. Some theory analysis was performed to investigate the PBSD performance of CFST structures. This is referred to further study on PBSD for CFST structures.
Seismic Behavior of R.C. T-Shape Columns Strengthened with CFRP and Steel Plate
Authors: Zhou Ming Jie , Niu Jie , Tian Wen Ling , Wang Ling
Published: December 2010

In this paper, with the methods of bonding steel, CFRP and complex strengthening, four R.C. T-shaped columns are reinforced. The experimental researches of the above four reinforced columns and one not reinforced in the low-cycle repeated loads are completed. Carrying capacity, energy dissipation, ductility and other characteristics of the T-shaped columns are studied. The results show that: the flexural bearing capacity of the T-shaped columns reinforced with bonded steel is substantially increased; the ductility of the T-shaped columns reinforced with CFRP is substantially increased too; the bearing capacity, ductility and energy dissipation of the T-shaped columns reinforced with complex method are increased synchronously.
On the Relationship between Deteriorated Level of ASR Damaged Concrete and Lithium Migration from Acceleration Lithium Migration Technique Test
Authors: Wang Wei Chien , Liu Chih Chien , Lee Chau
Published: December 2010

This research is to study the effect of deteriorated level on the ions migration in inhibiting the concrete damaged by ASR using electrochemical technique. Cylindrical concrete specimens made by reactive sandstone with 10 cm diameter and 5 cm height were prepared at the ages of 7, 14, 28, 90, and 180 days curing in a 38°C and 100% R.H. storage environment. The accelerated lithium migration technique (ALMT) was performed using LiOH H2O and Ca(OH)2 as electrolytes for anode and cathode, respectively. 9 A/m2 current density was used to drive lithium ion into and remove sodium ion out of the concrete. The results show that the rates of ions migration increase with increasing the deteriorated level of specimen. Furthermore, a linear relationship exists between the non-steady state migration coefficient of Li+ and the deteriorated level of specimen.
Parallel Computing Traveling Wave Effect on the Seismic Response of 3D Valley Topography Site under Long-Period Seismic Excitation
Authors: Zhang Wei , Zhu Min Wei , Shan Tao Tao
Published: December 2010

In this paper, three typical bedrock long-period seismic waves and two commonly used waves were selected for three dimensional seismic responses parallel computation of a valley topography site under uniform excitation and traveling wave excitation. The equivalent-linear analysis method was used in simulation of soil’s non-linear properties. Computation results showed that horizontal acceleration response increase and vertical acceleration response decrease under long-period seismic wave excitation compared with those under commonly used waves excitation. When considering wave traveling effect, the horizontal acceleration response decrease and the vertical acceleration response increase. The conclusions are useful for relevant engineering projects. Parallel computation was also performed to raise computational efficiency.
Interaction of Multiple Semi-Cylindrical Gaps and a Shallow-Buried Cavity
Authors: Zhang Rui , Li Hong Liang
Published: December 2010

In modern municipal construction and earthquake engineering, semi-cylindrical gap and shallow-buried cavity structure are used widely. In this paper, the solution of displacement field for elastic semi-space with multiple semi-cylindrical gaps and a shallow-buried cavity while bearing anti-plane harmonic line source force at any point is studied. In the complex plane, considering the symmetry of SH-wave scattering , the displacement field aroused by the anti-plane harmonic line source force and the scattering displacement field impacted by multiple semi-cylindrical gaps and a cylindrical cavity comprised of Fourier-Bessel series with undetermined coefficients which satisfies the stress-free condition on the ground surface are constructed. Through applying the method of multi-polar coordinate system, the equations with unknown coefficients can be obtained by using the stress-free condition of the gaps and the cylindrical cavity in the radial direction. According to orthogonality condition for trigonometric function, these equations can be reduced to a series of algebraic equations. Then the value of the unknown coefficients can be obtained by solving these algebraic equations. The total wave displacement field is the superposition of the displacement field aroused by the anti-plane harmonic line source force and the scattering displacement field. By using the expressions, an example is provided to show the effect of the change of relative location of semi-cylindrical gaps , the cylindrical cavity and the location of the line source force. Based on this solution, the problem of interaction of multiple semi-cylindrical gaps , a cylindrical cavity and a linear crack in semi-space can be investigated further.
Investigation on Applicability of Pushover Analysis on High-Rise Diagonal Grid Structural System
Authors: Teng Jun , Tu Hu Bing , Mao Huan Lin , Qiu Ying Liang
Published: December 2010

As an important seismic analysis method, Pushover is widely used in high-rise buildings, while there is still lack of investigation on applicability of Pushover analysis on diagonal grid structural system. Two structures with height 144 and 288 meters are respectively built, and then Pushover analysis and Incremental dynamic analysis are conducted. Results calculated by two different methods are compared, including top displacement vs. base shear curve, inter-story drift vs. inter-story shear curve, distribution of inter-story drift angle along the building height and plastic developing sequence of structural weak positions. Meanwhile, influence of three lateral load patterns (uniform pattern，inverted triangle pattern and SRSS pattern) on the results is investigated. Analysis results demonstrate that Pushover analysis can in some extent reflect seismic performance of structures and SRSS load pattern can better capture global and local information of structures compared with other two patterns.
First-Order Nonlinear Pseudo-Beat Vibration Model Identification of High Rise Buildings
Authors: Huang Dong Mei , Zhu Le Dong , Wang Qiu Fen
Published: December 2010

With vibration amplitude increasing, the super high-rise building appears obvious pseudo-beat vibration under the combination of vortex-induced force and nonlinear damping force. Therefore, based on Scanlan nonlinear empirical model the first-order nonlinear pseudo-beat vibration responses of the super high-rise building are deduced with KBM method. And then the aerodynamic parameters and vortex-induced force can be identified with least square method. By using the aeroelastic model wind tunnel test of a certain super high-rise building, the wind-induced displacement vibration responses are gathered. By the least square method, each aerodynamic parameter is identified. It shows by analysis that the pseudo-beat vibration force is mainly offered by linear and nonlinear damping forces but secondary offered by linear stiffness force and periodic excitation force. The pseudo-beat vibration force calculated by KBM approximation has the predominant frequency like that of beat vibration response as well as high-order harmonic wave.
Discussion on the Seismic Design Analysis Method of Masonry Building
Authors: Ren Xiao Song , Tao Yu Fei
Published: December 2010

The main seismic objective in China is defined as “no failure under minor earthquake, repairable damage under moderate earthquake and no collapse under major earthquake”. Both strength and deformation are important to evaluate the seismic performance. For masonry building, only the shear strength check under minor earthquake is stipulated in the current Chinese seismic design code. Due to the poor ductility of masonry building, the seismic design analysis method may not guarantee the collapse-resistant capacity under major earthquake. For the achievement of the seismic objective, the demand of ductility is discussed. A typical severely damaged masonry building by the 5.12 Wenchuan Earthquake of 2008 is presented for the analysis of the through X-shape crack on the load-bearing wall. In order to enhance the collapse-resistant capacity, the authors suggest more shear strength margin to take the influence of structural ductility into consideration. The feasible way can be easily realized as a target to raise the limitation for the shear strength check parameter under minor earthquake and to keep uniform seismic capacity in two directions. The investigated building is also illustrated here as an example to process the shear strength check for better seismic performance by the authors’ suggestion.
Long-Period Response Spectrum and Earthquake Response Analysis of Super High-Rise Building
Authors: Zhang Zhen Xuan , Chen Qing Jun
Published: December 2010

Based on seismic records with large long-period components at home and abroad, carried on uniform error correction processing and rough site classification, then, used numerical analysis software-MATLAB to calculate the average response spectrum of different types of venues, and used the least square method to do sub-fitting for them, got the long-period quasi-regulatory response spectrums of all kinds of venues; using the general-purpose finite element analysis software-ANSYS, a super high-rise building structural analysis model was established, inputted the fitted long-period seismic response spectrum and the design response spectrum of Shanghai anti-seismic standards, by comparing the results of structural seismic responeses under the two kinds of response spectrum, the long-period seismic response of super high-rise building was investigated, and some valuable conclusions were obtained for reference.
Study on Mechanical Properties of a through Tied Arch Bridge Model with Different Wind Bracing Forms
Authors: Di Sheng Kui , Bai Fu Zhou , Zhang Ai Li , Li Hui
Published: December 2010

A through tied arch bridge model was designed and fabricated with removable and replaceable wind bracing. Through two methods, numerical simulation and model experiments, the effects of different wind bracing forms were studied, which was to the static characteristics, dynamic characteristics and stability of such kind of bridges, and the advantages and disadvantages of different forms of wind bracing were compared, which provided the corresponding references for the selection of rational wind bracing in actual bridge project.
Experimental Investigation on Mid-Story Isolated Structures
Authors: Huang Xiang Yun , Zhou Fu Lin , Wang She Liang , Heisha Liu Han Wen , Luo Xue Hai
Published: December 2010

Isolation technique has been acceded as a part of the China Seismic Code for Design of Buildings. In this code, the limitations for using isolation design are very strict, superstructure must be regular and the isolation layer must be located on the top of base (base isolated structure). Because of the needs of architecture and function or the feasibility of technique, some limitations have been broken in recent projects. Sometimes isolated layer can be set on the intermediate story, so-called the mid-story isolated structure. According to the characteristic of structure, isolation layer of mid-story isolated structure is set on a place where the structure’s vertical stiffness is suddenly changed, as like the top of the first story, middle story, conversion story of the structure. Laminated rubber bearings (LRB) are adopted as an isolation layer. Because the isolation layer is set on intermediate story, the whole structure is divided into superstructure and substructure; the structure’s dynamic characteristics are changed. The mechanism of mid-story isolated structure appears different characteristic compared with base isolation. The aim of mid-story isolation is not only to reduce seismic responses of superstructure, but also to reduce seismic responses of the substructure. Theoretical analysis and the shaking table test of the mid-story isolated structure were carried. And the response of mid-story isolated structure is discussed by comparing with the response of base-isolated structure and base fixed structure. The key problems of mid-story isolated structure are the force condition and the interaction of the structure up and below the isolation layer. Many factors, such as the number of story, mass, stiffness of superstructure and substructure, parameter of the isolation layer, have influence on the seismic behavior of the mid-story isolated structure. The optimum combination relationship of these factors is presented and dynamic characteristics and dynamic responses are investigated.
Design Method of the Temporary Support Structure in Building Construction
Authors: Zeng Fan Kui , Hu Chang Ming , Liu Xing Cai
Published: December 2010

The uniform design standard of temporary support structure in building construction has not been published, In case of coupler steel pipe support system, characteristics for the temporary support structure, the standard structure of the system is proposed. It is suggested that the design of temporary support structure should be combined with the present theory of the design of steel structure. The design method of temporary support structure based on equivalent notional lateral loads is proposed. The formula is given, which is verified by tests and is compared with the formula recommended by the present code. The result shows that the formula can meet the requirements of the safety factor, which provides a reference for those concerned with research, design or construction.
The Application of Increment-Dimensional Blocks PIM on the Base-Isolated Structure
Authors: Zhang Xin Zhong , Han Ai Hong , Wu Zong Liang , Wang Chong
Published: December 2010

In this paper, seismic elastic and plastic responses of base-isolated structure are investigated, in which the bilinear restore-force model is employed for the isolation equipment. The mutual influences of both damping matrices and stiffness matrices are decoupled by using transition matrix. Based on the increment-dimensional precise integration method (PIM), the increment -dimensional blocks PIM is developed to separate structure characteristics and external forces, which can avoid the calculation of exponential matrices by PIM in each integration step. The results of numerical examples show that the efficiency of the new algorithm is very high in comparing with old method. The advantages of the new algorithm appear more obvious when the characteristics of large-scale structure have slightly changed, and only the external forces vary.
Time History Analysis of the Non-Symmetrical Special-Shaped Column Structure on Multi-Dimensional Seismic
Authors: Xu Dong Qiang , Wang Xue Yong , He Mei Mei
Published: December 2010

In this paper, the spatial analysis model of non-symmetrical special-shaped column is established in ANSYS, and then, the translational and rotational component of the seismic wave was input to the frame structural model, taking account of stiffness enhancement of the floor on the beam, and carried out the elastic-plastic time-history analysis. Simulations show that the trend of development of displacement basically the same way on two horizontal components and torsional acceleration component, and the displacement on two horizontal components and torsional acceleration component increases significantly compared with one horizontal component; because of the presence of the floor, the intensity of beam is enhanced, leading to some columns more strain than the beam, so the floor should be fully considered in the design of the beam.
Experimental Research on Aerodynamic Characteristics of Bridge Deck at Extreme Attack Angles
Authors: Xu Fu You , Li Bin Bin , Huang Cai Liang , Zhang Zhe
Published: December 2010

Long-span flexible bridges are always challenged by fierce wind load, and the wind with extreme-attack-angle may be a potential danger to threaten the bridge security. The three-component coefficients at extreme attack angles of the section model of one flat streamlined box-girder and central slotted box-girder are investigated through the wind tunnel test, and the detailed explanation are made. The results show that lift and pitch coefficients change approximately linearly between stall angles, and the coefficients display significant nonlinearity and a certain pulsation phenomenon when the attack angle exceeds stall angles, and the stall angles should not be less than ±10° for the sake of the safety of bridges.
Research on Torsional Vortex Resonance of a Streamlined Bridge Girder
Authors: Xu Fu You , Li Yong Ning , Lin Zhi Xing , Zhang Zhe
Published: December 2010

The vortex resonance characteristics of one typical streamlined bridge girder are studied using surface pressure measuring technique. Based on the testing results in smooth and turbulent flows with different attack angles, the means, standard deviations, power spectra of fluctuated pressures, as well as the correlations between local and total aerodynamic forces are comprehensively analyzed, and the torsional vortex vibration mechanism is disclosed. The research results indicate that, for the vortex resonance case, the flow separation at upper and lower surfaces is more severe than that of non-vortex case. The upper surface pressure fluctuation at the middle and downstream region is most obvious, which is incurred by the flow separation at the upper surface upstream tip. At the middle and downstream region, the aerodynamic forces keep good correlations with the total forces, and they provide the major torsional moment for vortex resonance. Vortex vibration depends on both fluctuation intensity and peak location. For the vortex resonance case, the surface fluctuated pressures are locked in the same frequencies.
AMD Application for Suppressing the Lateral and Torsion Buffeting Response of Suspension Pipeline Bridge
Authors: Chen Xi , Xu Fu You , Qiu Wen Liang , Zhang Zhe
Published: December 2010

Active Mass Damper has been proven to be efficient in suppressing structure vibration. Previous studies of AMD have been concentrated on the vibration control of buildings under earthquake excitation, whereas few investigation of wind-induced bridge vibration control has been conducted. In consideration of the characteristics of one suspension pipeline bridge which behaves dramatic lateral and torsional response under fluctuating wind action, a two-DOFs TMD/AMD system for suppressing both lateral and torsional responses was proposed. The bridge is modeled using Ansys and the buffeting responses of the bridge under TMD, AMD control are respectively simulated and analyzed by MATLAB/Simulink. The efficiency of different control system has been studied. The results show that two-DOFs AMD system has a better performance in suppressing the buffeting response of lateral bending and torsion. In addition, AMD system can be applicable to a wider range of frequency and therefore manifests the more stable performance than TMD under fluctuating wind loads which contain various frequency components.
Numerical Simulation of Backward Facing Step Flow Using Nonlinear Eddy Viscosity Model
Authors: Wang Ting Ting , Yang Qing Shan
Published: December 2010

Nonlinear eddy viscosity models have received significant interest because of the shortcomings of linear eddy viscosity models used in the numerical simulation of flow around building structures. There are many kinds of nonlinear eddy viscosity models. This paper adopts one of them to simulate backward facing step flow, which aims to evaluate the properties of this turbulence model. Compared with linear eddy viscosity model and experimental measurements, the simulation of nonlinear eddy viscosity model gives better results, especially for the reattachment length and pressure coefficient values. For this reason, this nonlinear eddy viscosity model is more suitable for numerical simulation of complex flow around building structures than linear eddy viscosity model.
Experimental and Numerical Studies on Flexural Behavior of Casing Joint of Square Steel Tube
Authors: Ding Min , Hou Zhen Hua , Jiang Xiu Gen , He Yu Zhi , Zhang Guang Kui , Ju Jin San
Published: December 2010

The tests on thirteen specimens of casing joints of square steel tube were conducted to investigate the flexural behavior of the joints. And numerical simulation studies on that were carried out by ANSYS/LS-DYNA. On this basis, effects of tube wall thickness, tube edge length, and inserting depth on failure mode, ultimate flexural capacity and deformation of the joints were discussed. The results show that there are two types of failure modes, i.e., inside tube yield failure and outside tube shear failure. Ultimate flexural capacity and rigidity of the joints increased with the inserting depth increasing. The ultimate flexural capacity is proportional to tube shear strength, tube wall thickness, inserting depth, and tube edge length.
Study on Seismic Performance of Coupled Shear Walls with Vertical Dampers
Authors: Pan Chao , Weng Da Gen
Published: December 2010

A new damping wall system is proposed to improve the seismic performance of high-rise coupling shear walls. The coupling beams of the proposed wall are slit in the middle with damping devices (steel dampers) installed in the slit vertically aiming to dissipate energy during earthquakes and prevent severe damage of the structure. A FEM program named OpenSees is used to analyze the seismic performance of the new damping wall utilizing macro finite element model. During the analysis, influence of damper parameters and other factors on seismic performance of the damping wall is considered, and the analysis indicates that with proper damper parameters, the new damping wall can be provided with better seismic performance compared with the conventional wall.
A Study on Dissipation of Cumulative Hysteretic Energy in Reinforced Concrete Frame Structures
Authors: Guan Min Sheng , Han Da Jian , Du Hong Biao , Wang Xin
Published: December 2010

Earthquake input energy and structural energy dissipation are key indicators to assess the seismic performance of structures. To study the rules of distribution of hysteretic energy within structures, a 6-storey regular reinforced concrete frame structure model is analyzed through elasto-plastic time-history dynamic analysis using the El Centro and Northridge accelerograms. Based on the comparison between numerical results for the earthquake input energy and structural hysteretic energy under the minor, moderate and major earthquakes of Grade 8 and 9, the distribution of the ratio of the storey hysteretic energy to the total hysteretic energy through the height was further studied. It shows that the computed results corresponding to the two earthquake records are in good agreement under different ground motion severity. And the percentage of structural hysteretic energy to input energy is basically stable. The distribution pattern of storey hysteretic energy through the height is that the value of the upper stories is smaller than the value of the lower stories. And the ground motion severity has a minor influence on the distribution pattern when the plasticity of structure develops more sufficiently.
Research on the Wind Environment around the Wenyuan Building in Tongji University
Authors: Yang Li
Published: December 2010

The wind environment simulation analysis on planning scheme with computer is still in the exploratory phase. In this paper, the research took years of average meteorological factors of Shanghai as initial conditions to simulate the wind environment around the Wenyuan Building with a flow field simulation analysis of Fluent Airpak [1]. The simulation results were used to analyze the distribution of whirlpool, wind shadow zone, etc and the influence they had made. The experiment indicates that it has a practical value and the guidance meaning for architectural complex planning to simulate the building’s surrounding microscopic climate with Fluent Airpak.
Seismic Performance Evaluation of SRC Frames Based on Incremental Dynamic Analysis
Authors: Wang Qiu Wei , Shi Qing Xuan , Men Jin Jie
Published: December 2010

Incremental dynamic analysis (IDA) is an effective method for evaluation of seismic performance of building structures. Based on the principle and characteristics of IDA method, evaluation steps of investigating deformation and ductility of steel reinforced concrete (SRC) structures under increasing earthquake loading are put forward. Limit states of different performance levels for structures are connected with IDA curve slope whose decrease amplitude is determined according to current test data. Based on the proposed constitutive model of steel and concrete, a regular steel reinforced concrete frame structure is analyzed with IDA method, and distribution of story drift angle and ductility for four performance levels are investigated. The calculation results show that the SRC frame has better seismic performance when subjected to random earthquake waves.
Probability Distribution Analysis of Structural Response under Non-Gaussian Wind Loads
Authors: Li Jing , Wang Xin
Published: December 2010

Based on the theory of maximum likelihood estimation, a set of nonlinear equations is first derived for determination of parameters of Weibull distribution. To speed up convergence, an efficient algorithm is proposed for solving the parameters. Further, a large-span roof structure is taken to demonstrate the proposed method. It is proved that the responses of a nonlinear structure have non-Gaussian properties under the excitation of non-Gaussian stochastic wind pressure field. By Weibull distribution fitting, the maximum and minimum values of structural response with a certain assurance rate are computed, and the results are compared with those obtained from normal distribution.
Effects of Spatial Variable Ground Motions on the Seismic Response of Base-Isolated Building
Authors: Lei Yong Qin , Du Yong Feng
Published: December 2010

Aimed to base-isolated building with large plane dimension, the change laws of seismic response for base-isolated building under spatial variable ground motions were researched. Firstly, the artificial spatial variable earthquake time histories were generated using spectral representation method based on code response spectrum. Then the 3-D FEM modal of one based-isolated building with large plane dimension was established and the seismic response of based-isolated building under spatially ground motion was studied by nonlinear time history analysis. The mitigation effects of based-isolated building with large plane dimension were compared each other at the cases of uniform excitation, non-uniform excitation considering only wave passage effect, non-uniform excitation considering both the wave passage effect and incoherence effect, multi-component uniform excitation, multi-component non-uniform excitation considering the wave passage effect and multi-component non-uniform excitation considering both the wave passage effect and incoherence effect. The results show that the seismic response of base-isolated structure with large plane dimension under the uniform excitation is relative safety. When the base-isolated building with large plane dimension is designed by time history analysis, the spatial variability of earthquake ground motion effects can be considered.
Seismic Performance Spectra
Authors: Liu Wen Feng , Fu Xing Pan
Published: December 2010

The seismic performance spectrum is a new kind of the response spectra which is formed according to the designated performance objectives. The performance objectives are changed according to the performance objective level and period of structure, and are different in the acceleration sensitive, velocity sensitive and displacement sensitive range in the seismic performance spectrum. The seismic performance spectrum formulas are derived, which demonstrate the mathematic relationship between the seismic demands of the different performance objective levels and the period of structure. The fitted formulas of the seismic performance spectra for seismic design are obtained due to statistical result of 1085 ground motion records. The new seismic performance spectra are shown in visual three-dimension figures which can represent the seismic demand, performance objective and period of structure in this paper. The philosophy of the seismic performance spectrum is analyzed which reveals the rules for estimating seismic demand of structure at the different performance objective levels. So the multi-objective performance-based seismic design is also proposed using the seismic performance spectrum.
Design for Composite Liners of Landfill under Alternating Cycles of Wetting-Drying and Freezing-Thawing
Authors: Wang Hong Yu
Published: December 2010

The design conception of composite liners consisting of a geomembrane (GM), geosynthetic clay liners (GCLs) and compacted gravel soils for landfill is presented based on the climate characteristic, gravel soils material storage in abundance, and GCLs having been exported all over the world for various applications. The analyses results suggested that the capacity to resist the collapse of wetting-drying and freezing-thawing, long-term barrier performance, and the general sliding stability of barrier system are enhanced obviously by using GCLs/GM as barrier and displacing clay by gravel soils as protector in this paper. It will be plausible as effective design for the barrier system of landfill under wet-dry and freeze-thaw alternating cycles in northwest China.
Preparation of Residual Soil Samples by Using Modified Method
Authors: Baharudin Noor Hasnida , Kasa Anuar , Chik Zamri , Adnan Azlan , Mohd Raihan Taha
Published: December 2010

The purpose of this study was to establish an alternative method in preparing the residual soil samples for laboratory tests. The soil was compacted by using the modified method in order to get the desired values of dry unit weight that was equivalent to the values obtained from standard compaction method. The advantage of using this method was that, due to its larger size, more samples could be taken and tested under the same compaction condition and the mould could be directly mounted on the shaking table with the addition of the air bags to avoid the occurrence of boundary effects. The soil was compacted in a 300mm x 300mm x 300mm mould by using the vibrating hammer. The results of this study showed that the average dry unit weight value of 13.4 kN/m3, 13.6 kN/m3 and 13.7 kN/m3 obtained from 5 rounds/layer, 6 rounds/layer and 7 rounds/layer of compaction of modified method, was equivalent to about 92%, 93 % and 94% of maximum dry unit weight obtained from standard compaction method, respectively.
Effect of NH4H2PO4 Content on Properties of the Mullite-Based Investment Materials
Authors: Yu Gui Lin , Li Nan , Li You Sheng , Wang Yi Ning
Published: December 2010

The relationships between NH4H2PO4content and properties including apparent porosity, bulk density, compressive strength, setting expansion and thermal expansion of the mullite-based investment materials have been investigated. The results show that: With increment of NH4H2PO4content, the bulk density decreases and the apparent porosity increases for the specimens. When the NH4H2PO4 content is less than 9 mass%, the compressive strength of the specimens clearly decreases with increment of NH4H2PO4content, and the compressive strength of the specimens heated at 900°C is less than that of the specimens heated at 110°C slightly. With increment of NH4H2PO4content, the setting expansion obviously increases and the thermal expansion decreases a little.
Simplified Method of Active Earth Pressure for Special Inner Support Structure
Authors: Zhang Zhong Miao , Fang Kai , Liu Xing Wang
Published: December 2010

A method is proposed for the calculation the earth pressure exerted on the inner wall of a special double-row support structure. The analysis shows that there is a pressure gradient between the walls and an amplification coefficient is introduced to reflect the increase of the earth pressure. The predicted and observed behaviors are compared to examine the feasibility of this method and the result shows that this method gives the closest prediction of the deflection of the inner wall.
Impact of Mandatory Medical Insurance on Construction Contractors in Saudi Arabia
Authors: Alsugair Abdullah M
Published: December 2010

The comprehensive development in Saudi Arabia forced the private sector to bring foreign employees to assist in accomplishing this development. The number of foreign employees reached to six million people according to the late statistics. This huge number of people exerted pressure on the public free medical facilities that forced the government to issue a decree that instructs private sector to use private medical facilities for their foreign employees. The private sector dealt with this decree in different ways according to the perception of the company from providing full medical coverage for their employees to providing nothing. This has created a problem to many foreigners in which they have to pay for their medical needs. The government, then, issued a new decree that is the mandatory medical insurance. This decree requires the private sector to provide full medical coverage for their foreign employees. This decree will have an impact on the construction companies (contractors) and the cost of the construction projects. This paper presents results of a study conducted to identify the impact of the mandatory medical insurance on the construction contractors in Saudi Arabia. The methodology used was to prepare a questionnaire that investigates the objectives of this study and distributes it to the contractors. The questionnaire includes many aspects among them the impact of this decree on the company performance and the competition between contractors; how this extra expense being dealt with; and the impact on the employee. The questionnaires were distributed to 150 construction contractors and 90 questionnaires were collected. Results of the study reveal the impact of the mandatory medical insurance on the construction contractors in general and according to their classifications. In addition, the study presents the current practice implemented by contractors to provide medical care for their foreign employees.
Development and Application of High-Performance Self-Compacting Fair-Faced Finish Concrete under Complex Conditions
Authors: Gao Chun
Published: December 2010

With the support of the Wuhan railway station of Passenger Transport Line from Wuhan to Guangzhou which was completely furnished, the characteristic of zeolite in concrete made best of, the main factors including cementing materials, additives, admixtures and sand rates were researched through experiment and the effective testing method determined, the self-compacting fair-faced finishing concrete is achieved, and 6600m³ of the concrete is applied. The developed self-compacting concrete has good effect finish, reduce the labor intensity by the character of self-compacting, and save construction period. The level of Green construction is also upgraded.
Stability Analysis of Floating-Roof Tanks under Differential Settlement
Authors: Zhao Yang , Lei Xiang , Zhang Xing
Published: December 2010

Vertical cylindrical steel tanks are sensitive to differential settlement beneath the tank wall. Most previous studies were based on idealized harmonic settlement, however, for thin shell structures of high nonlinear behavior, it is obviously inappropriate to obtain the results under real settlement by simple summation of harmonic solutions. Real settlement of steel tanks can be grouped into two types - global differential settlement and local differential settlement. This paper examines the nonlinear response and stability behavior of floating-roof steel tanks under both types of settlement. It is shown that, for tanks under global differential settlement, local buckling occurs at the eave ring, followed by a stable post-buckling behavior, and final failure is by overall buckling of the tank shell; while for tanks under local differential settlement, the structural response is related to the degree of localization. At highly localized settlement, local snap-through buckling occurs at the tank wall, but it does not lead to a serious consequence, and the post-buckling behavior can also be utilized in design.
Resisting Seismic Behavior Study of an Adding Cover-Plate Protocol Used For D-Type Eccentrically Braced Steel Frames
Authors: Pan Xiu Zhen , Hao Ji Ping , Gao Jie
Published: December 2010

This paper suggests a new connection protocol, adding cover-plate between shear links and column, which was used to enhance moment and shear carrying capacity of beam, relax the restriction and assure the sufficiency development of plastic deformation of the link, and dissipate more earthquake energy. Considering the scale ratio of 1:3, the experimental data was achieved by a specimen under cyclic loading, which was verified by nonlinear finite element analyses. Results indicate that the new type of eccentrically braced steel frame have enough stiffness and deformation capacity, draw link away from flange of column, and dissipate more earthquake energy. The single diagonal eccentrically braced frames adopted adding cover-plate protocol will ensure sufficient lateral stiffness under ordinary circumstances, including lateral loads due to wind and moderate seismic disturbances, have preferable resisting seismic behavior under rare earthquake, and be so practical and costly that it can be easily applied in present project.
Analysis of Semi-Rigid Joint Frame with Moment-Rotation and Shearing-Deformation Relationships
Authors: Duan Shu Jin , Zhang Yan Qing
Published: December 2010

A mathematic model for semi-rigid joint frame is proposed, in which, both the moment-rotation and shearing-deformation characteristics of joint are taken into account. For element with simi-rigid joints, the stiffness matrix is derived, and some equivalent nodal force vectors are obtained when the element is subjected to different loads. The internal force distribution and the deformation in structure are greatly affected by the moment-rotation and shearing-deformation relationships of joints.
Study on Stability Round Stronger Axis of the Column with Composite Section of Double Limbs under Axial Compression
Authors: Wang Deng Feng , Wang Yuan Qing , Shi Yong Jiu , Fang Bin
Published: December 2010

The section of the column under axial compression used in a certain electrostatic precipitator is composed of double H shaped steel limbs and the stiffened connecting web by weld. As the width of connecting web usually exceeds 3 times of the section height of H shaped steel, the axis which connecting web lies in is the weaker axis for the stiffness of column section, while the midperpendicular of connecting web is the stronger axis. In consideration of initial geometrical imperfections and weld residual stresses, the study on stability round the stronger axis of column subjected to axial compression by nonlinear finite element method is conducted. The research results indicate that the column doesn’t present the flexural buckling round the stronger axis, but present the elasto-plastic flexural-torsional buckling. A buckling factor is produced to measure the stability performance of column round stronger axis. When the connecting channel shaped steels between two limbs and the stiffeners located on connecting web are strengthened, the buckling factor increases slightly. When the width-thickness ratio of connecting web increases, the buckling factor decreases significantly. When the slenderness of H shaped steel round the stronger axis is kept constant and the height-thickness ratio of H-shaped steel web increases, the buckling factor increases. Based on a great many computation results, the regressed recommendation is proposed how to evaluate the design buckling bearing capacity of column under axial compression round stronger axis.
Research on Bearing Capacity of Steel Tube-Reinforced Concrete Column Subjected to Eccentric Compression Load
Authors: Guo Quan Quan , Hu Jie Ting
Published: December 2010

Nonlinear constitutive law was used in this paper. On the basis of plain section assumption, through isoparametric element theory, nonlinear secant and tangent stiffness matrices of section were derived. Nonlinear equation was solved by Newton-Raphson method. The bearing mechanism under the eccentric compression was revealed by changing eccentricity and position coefficient. The result is found to be in good agreement with the experimental data, and it shows that large and minor eccentricity failure mode, which are similar to reinforced concrete, are existed in steel tube-reinforced concrete column. In addition, force-moment correlation curve is derived. By calculation and comparison. The ultimate capacity is found to be greatly underestimated in the current technical specification.
Mechanical Properties of a One-Way Beam String Structure with the Cooperation of the Supporting Structure
Authors: Nie Yun Jing , Li Tie Ying
Published: December 2010

In this paper, taking a practical project for the study, using the finite element analysis software ANSYS, static analyses under different load conditions are performed on a single beam string structure (BSS) and a one-way beam string structure with the cooperation of the supporting structure, respectively. Moreover, influence of factors on mechanical properties of the one-way BSS with the cooperation of the supporting structure is investigated. The factors include grouting, support form, corrosion. The results can provide a reference for design and construction of the same type of structure.