The Effect of Core Eccentricity on the Structural Behavior of Concrete Tall Buildings

The main purpose of this paper is to investigate the effect of core eccentricity on the structural behavior of concrete tall buildings.Concrete buildings of 55 floors with plan dimensions 48.0×48.0 m2 were investigated.Three cases of main core locations are studied:centric(A),eccentric by one sixth(B)and one third(C)of building width.The three-dimensional finite element method has been used in conducting structural analysis through ETABS software.Gravity and lateral(wind and seismic)loadings are applied to all building cases.It has been concluded that the core location is the prime parameter governing the structural behavior of tall buildings.Although the first two cases(A,B)have acceptable and similar structural behaviors conforming to code limits,in the third case(C),the building behavior came beyond code limits.The author introduced remedial action by adding two secondary cores in the opposite direction of the main core(C-R)to restore the building behavior to the code limits.The results of this action were satisfactory.

A Review of Current Researches on Blast Load Effects on Building Structures in China

The damages of building structures subjected to multifarious explosions cause huge losses of lives and property. It is the reason why the blast resistance and explosion protection of building structures become an important research topic in the civil engineering field all over the world. This paper provides an overview of the research work in China on blast loads effect on building structures. It includes modeling blast shock wave propagation and their effects, the dynamic responses of various building structures under blast loads and the measures to strengthen the building structures against blast loads. The paper also discusses the achievements and further work that needs be done for a better understanding of the blast loads' effects on building structures, and for deriving effective and economic techniques to design new or to strengthen existing structures.

Seismic response of tall building considering soil-pile-structure interaction

The seismic behavior of tall buildings can he greatly affected by non-linear soil-pile interaction during strong earthquakes.In this study a 20-storey building is examined as a typical structure supported on a pile foundation for different conditions:(1) rigid base,i.e.no deformation in the foundation:(2) linear soil-pile system;and (3) nonlinear soil-pile system. The effects of pile foundation displacements on the behavior of tall building are investigated,and compared with the behavior of buildings supported on shallow foundation.With a model of non-reflective boundary between the near field and far field, Novak's method of soil-pile interaction is improved.The computation method for vibration of pile foundations and DYNAN computer program are introduced comprehensively.A series of dynamic experiments have been done on full-scale piles, including single pile and group,linear vibration and nonlinear vibration,to verify the validity of boundary zone model.

A novel 300 kW arc plasma inverter system based on hierarchical controlled building block structure

To date, the high power arc plasma technology is widely used. A next generation high power arc plasma system based on building block structure is presented. The whole arc plasma inverter system is composed of 12 paralleled units to increase the system output capability. The hierarchical control system is adopted to improve the reliability and flexibility of the high power arc plasma inverter. To ensure the reliable turn on and off of the IGBT module in each building block unit, a special pulse drive circuit is designed by using pulse transformer. The experimental result indicates that the high power arc plasma inverter system can transfer 300 kW arc plasma energy reliably with high efficiency.

Research on semi-active control method of a building structure based on non-smooth control

This study investigates the effectiveness of the non-smooth semi-active control algorithm on suppressing the vibration performance of a building structure subjected to seismic waves. According to the Lyapunov stability theory, it has bene proven that the non-smooth semi-active control algorithm can achieve a finite-time stability of the vibration relative to the isolation layer of a building structure. Through numerical simulation of two buildings with different parameters subjected to the input of a seismic wave, the vibration conditions of passive control, LQR semi-active control and non-smooth semiactive control are compared and analyzed. The simulation results show that the non-smooth semi-active control algorithm has a better robustness and effectiveness in restraining the impact of earthquakes on the structure.

Vibration Control of a High-Rise Building Structure:Theory and Experiment

In this study,an innovative solution is developed for vibration suppression of the high-rise building.The infinite dimensional system model has been presented for describing high-rise building structures which have a large inertial load with the help of the Hamilton’s principle.On the basis of this system model and with the use of the Lyapunov’s direct method,a boundary controller is proposed and the closed-loop system is uniformly bounded in the time domain.Finally,by using the Smart Structure laboratory platform which is produced by Quancer,we conduct a set of experiments and find that the designed method is resultful.

Methods for Progressive Collapse Analysis of Building Structures Under Blast and Impact Loads

Progressive collapse of building structures under blast and impact loads has attracted great attention all over the world. Progressive collapse analysis is essential for an economic and safe design of building structures against progressive collapse to blast and impact loads. Because of the catastrophic nature of progressive collapse and the potentially high cost of constructing or retrofitting buildings to resist it, it is imperative that the progressive collapse analysis methods be reliable. For engineers, their methodology to carry out progressive collapse evaluation need not only be accurate and concise, but also be easily used and works fast. Thus, many researchers have been spending lots of effort in developing reliable, efficient and straightforward progressive collapse analysis methods recently. In the present paper, current progressive collapse analysis methods available in the literature are reviewed. Their suitability, applicability and reliability are discussed. Our recent proposed new method for progressive collapse analysis of reinforced concrete frames under blast loads is also introduced.

Safety analysis of optimal outriggers location in high-rise building structures

This paper presents the restraining moments of outriggers acting on the core wall and the equation of the horizontal top deflection based on a simplified outrigger model. The deformation compatibility conditions between outriggers and core wall as well as the finite rigidities of outriggers are also considered. One case study was carried out to analyze the horizontal top deflection and the mutation of the restraining moments caused by the variation of outrigger location. The results showed that the method adopted in the paper is simple and reasonable. Some conclusions are valuable to the safety design of high-rise building structures.

FUZZY MATHEMATICAL EVALUATION FOR MASONRY STRUCTURE BUILDINGS' DAMAGE GRADE CAUSED BY COAL MINING

Coal mining under buildings certainly causes surface movement and deformation, therefore, it brings about deformation even fracture for buildings. It is an important task to evaluate correcly the buildings’ damage grabe caused by coal mining. Fuzzy comprehensive evaluation,considering some factors of buildings’ fracture, has been applied to analyze the masonry structure buildings’ damage grade affer coal mining in this paper. It provides a scientific basis for buildings’reidercement before mining and maintenance or compensation after mining.

Experimental study of friction dissipators for seismic protection of building structures

This paper presents the results from unidirectional shaking table tests of two reduced scale steel models of a building frame, with one and two floors, respectively. These frames incorporate friction dissipators at every floor. The inputs are sine-dwells and artificial and registered earthquakes. This study is part of a larger research project aiming to assess the seismic efficiency of friction dissipators by means of an integrated numerical and experimental approach. Inside this framework, the main objectives of these experiments are to： （i） collect a wide range of results to calibrate a numerical model derived within the project, （ii） clarify some of the most controversial issues about friction dissipators （including behavior for inputs containing pulses, capacity to reduce resonance peaks, introduction of high frequencies in the response, and self- generated eccentricities）, （iii） better understand their dynamic behavior, （iv） provide insight on the feasibility and reliability of using simple friction dissipators for seismic protection of building structures and （v） characterize the hysteretic behavior of these devices. Most of these objectives are satisfactorily reached and relevant conclusions are stated.

Structural Design of a Tall Building with Underpinning Structure in Guangzhou

This paper introduces the structural design optimization of a tall building with reinforced concrete frame-core shear walls in Guangzhou downtown.To decrease the construction cost,wide flat beam with 400 mm ×650 mm rectangular cross-section are adopted for main beam.Special measures are used to decrease noncoincident centers of mass and stiffness.Because subway tunnels cross the building underground,inclined columns,the second and third floor underground together function as the underpinning structures.Different from traditional transform beam,the proposed underpinning structures show good performance without using large dimensional bending members.Special attentions should be paid to the beams connecting with the inclined column in the underpinning structures,and these beams show large tensile or compressive forces.Settlement observations after completion construction indicate that the building as well as the proposed design measures work well.

Synthesis and Crystal Structure of a 2D Cu Framework Constructed from Dinuclear Building Units

A novel 2D Cu coordination polymer [Cu4(pca)4(H2O)2(DMSO)2·2DMSO·2H2O]n(2, H2 pca = pyrazole-3-carboxylic acid) has been prepared by dissolving a dinuclear Cu complex Cu2(py)3(pca)2(H2O)·(H2O)(1) in DMSO solution and structurally characterized by X-ray diffraction. The polymer crystallizes in space group P1 with a = 9.538(3), b = 9.714(3), c = 10.765(3) A, α = 86.492(6), β = 84.007(7), γ = 82.592(6)o, Mr = 1079.04, V = 982.4(5) A3, Z = 1, Dc = 1.824 g/cm3, μ = 2.425 mm-1 and F(000) = 548. The final refinement gave R = 0.0785 and w R = 0.1940 for 2787 reflections with I 】 2σ(I). The structure of 2 consists of Cu4(pca)4(H2O)2(DMSO)2·2DMSO·2H2O units, which can be viewed as two dinuclear subunits of Cu2(pca)2(H2O)2 and Cu2(pca)2(DMSO)2 connected to each other alternately, with solvent DMSO and H2 O molecules around. The framework features a grid-like topology, with the walls of the grids composed of Cu4(pca)4 units, and the coordinated solvent molecules trapped in the grids.

A Parallel FEA Computing Kernel for Building Structures

With the rapid development of high-rise buildings and long-span structures in the recent years, high performance com- putation (HPC) is becoming more and more important, sometimes even crucial, for the design and construction of com- plex building structures. To satisfy the engineering requirements of HPC, a parallel FEA computing kernel, which is designed typically for the analysis of complex building structures, will be presented and illustrated in this paper. This kernel program is based on the Intel Math Kernel Library (MKL) and coded by FORTRAN 2008 syntax, which is a parallel computer language. To improve the capability and efficiency of the computing kernel program, the parallel concepts of modern FORTRAN, such as elemental procedure, do concurrent, etc., have been applied extensively in coding and the famous PARDISO solver in MKL has been called to solve the Large-sparse system of linear equations. The ultimate objective of developing the computing kernel is to make the personal computer have the ability to analysis large building structures up to ten million degree of freedoms (DOFs). Up to now, the linear static analysis and dynamic analysis have been achieved while the nonlinear analysis, including geometric and material nonlinearity, has not been finished yet. Therefore, the numerical examples in this paper will be concentrated on demonstrating the validity and efficiency of the linear analysis and modal analysis for large FE models, while ignoring the verification of the nonlinear analysis capabilities.

Research of CBR, DM and smart algorithms based design methods for high-rise building structure form-selection

First, the high-rise building structure design process is divided into three relevant steps, that is, scheme generation and creation, performance evaluation, and scheme optimization. Then with the application of relational database, the case database of high-rise structures is constructed, the structure form-selection designing methods such as the smart algorithm based on CBR, DM, FINS, NN and GA is presented, and the original forms system of this method and its general structure are given. CBR and DM are used to generate scheme candidates; FINS and NN to evaluate and optimize the scheme performance; GA to create new structure forms. Finally, the application cases are presented, whose results fit in with the real project. It proves by combining and using the expert intelligence, algorithm intelligence and machine intelligence that this method makes good use of not only the engineering project knowledge and expertise but also much deeper knowledge contained in various engineering cases. In other words, it is because the form selection has a strong background support of vast real cases that its results prove more reliable and more acceptable. So the introduction of this method provides an effective approach to improving the quality, efficiency, automatic and smart level of high-rise structures form selection design.

Earthquake induced pounding between adjacent buildings considering soil-structure interaction

Many closely located adjacent buildings have suffered from pounding during past earthquakes because they vibrated out of phase. Furthermore, buildings are usually constructed on soil; hence, there are interactions between the buildings and the underlying soil that should also be considered. This paper examines both the interaction between adjacent buildings due to pounding and the interaction between the buildings through the soil as they affect the buildings＇ seismic responses. The developed model consists of adjacent shear buildings resting on a discrete soil model and a linear visco- elastic contact force model that connects the buildings during pounding. The seismic responses of＇ adjacent buildings due to ground accelerations are obtained for two conditions： fixed-based （FB） and structure-soil-structure interaction （SSSI）. The results indicate that pounding worsens the buildings＇ condition because their seismic responses are amplified after pounding. Moreover, the underlying soil negatively impacts the buildings＇ seismic responses during pounding because the ratio of their seismic response under SSSI conditions with pounding to those without pounding is greater than that of the FB condition.

Influence of soil——structure interaction on seismic collapse resistance of super-tall buildings

Numerous field tests indicate that the soilestructure interaction （SSI） has a significant impact on thedynamic characteristics of super-tall buildings, which may lead to unexpected structural seismic responsesand/or failure. Taking the Shanghai Tower with a total height of 632 m as the research object, thesubstructure approach is used to simulate the SSI effect on the seismic responses of Shanghai Tower. Therefined finite element （FE） model of the superstructure of Shanghai Tower and the simplified analyticalmodel of the foundation and adjacent soil are established. Subsequently, the collapse process of ShanghaiTower taking into account the SSI is predicted, as well as its final collapse mechanism. The influences ofthe SSI on the collapse resistance capacity and failure sequences are discussed. The results indicate that,when considering the SSI, the fundamental period of Shanghai Tower has been extended significantly,and the collapse margin ratio has been improved, with a corresponding decrease of the seismic demand.In addition, the SSI has some impact on the failure sequences of Shanghai Tower subjected to extremeearthquakes, but a negligible impact on the final failure modes. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

Studies on Seismic Identification and Reinforcement Design of Building Structures

China is a country with many earthquakes. Seismic safety monitoring and building earthquake-proofing technique are important means to protect the safety of people’s property in China. However, up to now, China’s seismic reinforcement and identification technology is still not mature enough. In particular, the 2008 Wenchuan earthquake caused great loss of life and safety to the Chinese people. This paper, takes seismic identification and reinforcement technology of building structures as the research object and summarizes the main methods of building structure seismic resistance in China. This paper is based on an in-depth analysis of the main seismic reinforcement and identification techniques in China, deeply analyzes the crux of anti-seismic and reinforcement of building structure combining with the current building seismic reinforcement typical cases, and puts forward some reasonable suggestions and improvement methods for the future development of building seismic identification and reinforcement design.

Optimal Vibration Control of Adjacent Building Structures Interconnected by Viscoelastic Dampers

The objective of this paper is to investigate the dynamic characteristics of two adjacent building structures interconnected by viscoelastic dampers under seismic excitations. The computational procedure for an analytical model including the system model formulation, complex modal analysis and seismic time history analysis is presented for this purpose. A numerical example is also provided to illustrate the analytical model. The complex modal analysis is conducted to determine the optimal damping ratio, the optimal damper stiffness and the optimal damper damping of the viscoelastic dampers for each mode of the system. For the damper stiffness and damping with optimal values, the responses can be categorized into underdamped and critically damped vibrations. Furthermore, compared to the viscous dampers with only the energy dissipation mechanism, the viscoelastic dampers with both the energy dissipation and redistribution mechanisms are more effective for increasing the damping ratio of the system. The seismic time history analysis is conducted to assess the effectiveness of the viscoelastic dampers for vibration control. Based on the optimal damping ratio, the optimal damper stiffness, the optimal damper damping of the viscoelastic dampers for a certain mode of the system, and the viscoelastic dampers can be used to effectively suppress the root-mean-square responses as well as the peak responses of the two adjacent buildings.

Evaluation of a Novel Approach for Automated Inventive Conceptual Design of Building Structures

This research is dedicated to assessment of a method that was earlier proposed and developed in order to increase the degree of automation and software involvement into conceptual decision making during design of structural elements of buildings. Such instruments of the theory of inventive problem solving as contradiction and function analysis and trimming formed the basis of the proposed approach that was realized in a modern building information modeling software. The common logic of the approach is also provided in the article. Qualitative research methods and particularly collecting, analyzing and interpreting data were applied in this research. Firstly, a literature review of indexed journal articles in the field of the study was performed and some trends for possible development of the topic were identified. Secondly, a survey of potential users of the methodology was conducted and analyzed. The questionnaire results showed that the suggested method and its technical realization gained attraction among respondents, however, some of them are rather cautious regarding application of the approach potentials in their practice. The paper ends with evaluation results discussion, conclusion and proposals for further research.

Describe the Process of Retrofitting Existing Buildings and Evaluate the Effectiveness of it in Improving the Seismic Performance of Structures in Earthquake-prone Regions

At present,earthquakes are a serious problem for building.Severe damages and collapses of buildings were caused by earthquakes in different degrees.It is reported that there are more than 68,858 deaths and hundreds of billions RMB losses in the May 12,2008 Great Wenchuan Earthquake[16].So,more attention should be paid to seismic technology.In order to face the challenges of earthquake on building,the seismic retrofitting was put forward,which“is the modification of existing structures to make them more resistant to seismic activity,ground motion,or soil failure due to earthquakes”[2].