Response Of High-rise Buildings Research Articles

Critical remarks on Rayleigh damping model considering the explicit scheme for the dynamic response analysis of high rise buildings

This paper numerically investigates the validity of Rayleigh damping model considering explicit operator to assess the dynamic response of high rise buildings under seismic loads. Considering transverse and longitudinal seismic waves, the bending moment, shear force, axial force, and and inter story drift are evaluated for a Core wall and a frame system of 46 story each. It is found that considering the explicit scheme, the dynamic responses are amplified significantly especially for axial forces. The reported amplification can be attributed to the ignorance of stiffness proportional Rayleigh damping coefficient which is associated with the stability issue of the implemented explicit operator. The paper indicates that Rayleigh damping model does not provide the required/expected damping for the higher modes of higher frequencies hence, it is not appropriate to be used along with the explicit operator especially for buildings of wide range of frequencies. It is worth pointing out that for classical dynamic analysis which follows the implicit scheme, Rayleigh damping seems to well consider the higher modes of high frequencies with higher damping ratio in comparison to the initial mode shapes. Consequently, the literature explicit scheme should be revised to accurately consider a proper damping for the higher modes which is crucial to assess the total response of structures of long periods and wide range of frequencies such as high rise buildings among others.

Life-cycle probabilistic seismic risk assessment of high-rise buildings considering carbonation induced deterioration

The geometrical and mechanical properties of reinforcing steels embedded in the RC structures may be deteriorated due to the aggressive environments, such as the carbonation, chloride, and wind-induced fatigue. The joint effects of aging and seismic load on the response of high-rise buildings are always neglected in current structural design specifications. This paper presents a probabilistic methodology to assess the time-dependent annual damage probability considering the carbonation-induced corrosion and the uncertainties associated with random variables under seismic excitations, which is implemented in a 42-story steel frame-RC core tube building. The loss of cross-sectional area and reduction in strength of reinforcements are considered in the analysis for the serviceability and safety limit states. The seismic hazard model and conditional fragility are integrated to compute the total annual damage probability of this building at different aging scenarios. Numerical results indicate that the carbonation-induced corrosion in reinforcements has significant impacts on the structural performances during its lifetime under both the serviceability and safety limit states. Neglecting the influences of deterioration may lead to erroneous predictions of damage probabilities for corroded high-rise buildings. The application of this study highlights the necessity of comprehensively discussing the detrimental effects of harsh environments on high-rise buildings, which may be neglected in the available literature.

Evaluation of energy-dissipating devices in high-rise RC core wall buildings

Energy-dissipating devices (EDDs) are used to control the dynamic response of high-rise buildings in moderate to severe seismic risk areas. These systems can be effectively analysed using a rigorous non-linear response history analysis (NLRHA) procedure. However, expertise and time is required to perform and interpret the results from this procedure since several trials are required to select the most effective size and location of the dampers. In this study, the validity of the modal strain energy (MSE) method and the logarithmic decrement (LD) method was checked using a case study of a 40-storey reinforced concrete (RC) core wall building equipped with buckling-restrained braces (BRBs) and fluid viscous dampers (FVDs). Linear and non-linear models of the building including dampers were prepared. The elastic dominant modes and their target displacements were then determined using a response-spectrum analysis procedure. The MSE and LD methods were used to determine the equivalent damping ratio and the time period for BRBs and FVDs, respectively. The base shear and roof displacement, determined using modal and spectral parameters against these damping and time = period values, were found to match those determined using NLRHA with an accuracy of 5–10% and 20–30%, respectively. This study is helpful for the preliminary sizing of EDDs.

The effect of soil–structure interaction on the along-wind response of high-rise buildings

Rapid population growth tends to lead to the construction of tall buildings. It is thus necessary to study the influential parameters on the behaviour of tall structures due to wind action. Soil deformability is one parameter that can affect the aerodynamic behaviour of tall structures. In this work, the impact of wind on the standard tall building of the Commonwealth Advisory Aeronautical Research Council, placed on a raft footing, was numerically modelled using Abaqus software. The wind was defined by a power function in the boundary layer of the atmosphere. Stream turbulence was modelled using the implicit large eddy simulation technique and a co-simulation was used to exchange non-uniform loads from the fluid domain to the structural domain. The mechanical reaction of the footing–soil framework was modelled using a direct strategy. Infinite boundary conditions were added to the numerical model for simulation of free boundaries and appropriate contact elements for sliding and separation between subsurface components were considered. The fluid and structural solutions were compared with the mean and root mean square values of experimental estimations for an extensive range of reduced speeds. Numerical results for the framework with soil–structure interaction (SSI) were compared with those without SSI. The dynamic properties and reactions of the building subjected to wind loading were affected by the SSI and therefore engineers should consider these parameters to guarantee practical designs.

Анализ поперечных виброударных колебаний высотных зданий на основе уравнения в частных производных

In order to overcome the problems of long analysis time, low accuracy and high energy consumption in traditional lateral vibration analysis methods of high-rise buildings, a new method of lateral vibration analysis of high-rise buildings based on partial differential equation is proposed. Based on Hamilton's principle, the partial differential equation of lateral vibration of high-rise buildings is established, and the Galerkin method is used to solve the partial differential equation until the discrete solution is obtained, and then the displacement response of high-rise buildings under different excitation frequencies is obtained. The experimental results show that compared with the traditional method, the proposed method has the advantages of short calculation time, high accuracy and low energy consumption.

Comparison between fixed base and isolated base in seismic response of high-rise buildings: a case study

In this study, the influence of soil condition under the isolated and fixed bases is studied by using ETABS 16 software for the high-rise regular building. A regular building with 10 floors is modeled and the results are obtained for story displacements, story shear forces and spectral acceleration according to Uniform Building Code 97 (UBC-97) code. The time history analysis has been performed by using 1999 Izmit earthquake record. 3 types of soil which had different stiffnesses are considered in this study. The results show that the value of base shear increases when the soil stiffness decreases. It also noticed that the spectral acceleration is larger in soft soil condition than that of other soil conditions; and this confirms that the structural response spectrum is associated with the soil condition. In addition, when using base isolated building the drift of lower floors will be larger than that of using base isolated, but in the upper floors the drifts of fixed base building will be larger than that of the isolated base building. Finally, time history method in the seismic design will produce base shear less than that from equivalent static method, so calibration factor for design purpose shall be used.

Advanced Control Strategy for Floor Response Replication of High-Rise Buildings Subjected to Earthquakes

ABSTRACT Seismic responses of high-rise buildings are dominated by the first few vibration modes; therefore, high-floor responses contain long predominant vibration periods. However, it may not be achievable to investigate the seismic performance of nonstructural facilities at high levels of high-rise buildings in the laboratory by using seismic shake tables because of the actuator stroke limitation. In this study, an advanced control strategy that incorporates a transfer system with modern control algorithms is proposed for shake tables to replicate high-floor responses of high-rise buildings subjected to earthquakes. First, design diagrams are proposed to determine the parameters of the transfer system. Then, a set of friction pendulums is adopted as the transfer system for the proof-of-concept stage. A mathematical model for the set of friction pendulums is developed for numerical studies prior to real experimental validation. Three linear controllers and three nonlinear controllers are designed and synthesized to verify the feasibility and applicability of the proposed strategy. Finally, the friction pendulum set is installed on a uniaxial shake table to replicate the roof responses of a 34-story building subjected to historical earthquakes. Experimental results demonstrate the proposed control strategy successfully replicates floor responses of the high-rise building that cannot be achieved formerly.

Response of High Rise Building with Conventional Brick and Light Weight Brick with Seismic Loads

In India population is increasing year by year and most of the land is highly productive and yielding three crops per a year , in that situation land acquisition has become quite expensive and housing cost goes on increasing, to solve this problem need to go for construction of High rise buildings. Now-a-days High rise buildings are a worldwide architectural phenomenon. To reduce the load on foundation we need to use lightweight materials. This project aims to carrying out seismic response of the high rise building with conventional brick and light weight brick. In this project a high rise office building of G+14 with plan dimensions of 19.2 m x 20.4 m and height 47.6m is considered for the analysis purpose using ETABS. Today, high rise buildings are a worldwide architectural phenomenon. The time require for calculating the load combination on them crave lot of time. The study includes understanding the main consideration factor that leads the structure to perform badly during earthquake in order to achieve their approx. behaviour under future earthquake. The main motive of this project is to scrutiny of a G+14 structure using ETABS. For greater height buildings, seismic load plays a vital role in both structural and safety considerations. The performance of the building is analysed for conventional bricks and light weight bricks. The comparison of obtained results for conventional and light weight bricks is done. The dynamic properties of this greater structures using with and without light weight bricks are investigated when subjected to lateral loading. loadings. It is observed that in case of lightweight bricks time period has increased, base shear is reduced and storey drift increases more at the base and less at the top.

Seismic Response of High Rise Building with Openings in Shear Walls

Due to gradual development of metros and small towns and increasing population in India, the high rise buildings are constructed at a larger scale due to land scarcity and the commercial or cultural importance of a particular area. A high rise building should be architecturally viable and should have good light and air ventilation. In this project we compare and analyze the high rise buildings in three configurations.A high rise building is a structure which is more than 30m in height. In this project we consider a high rise building with story configuration of G+20. The three configurations of the high rise building are designed, configured and seismically analysed using ETABS software. Earthquake analysis in ETABS is carried out on Model (a)-Structure without a shear wall, Model (b)-Structure with shear walls and Model (c)-Structure with openings in shear walls resting in Type II soil and Type III seismic zone. The soil type and seismic zone considered for this project is specific for Amaravati the capital of Andhra Pradesh. Seismic analysis results for each configuration of the high rise building such as Base Shear, Time Period, Storey Drifts and Displacements are compiled and compared to find the suitable configuration of high rise structure.

Optimal Design of Smart Mid-Story Isolated Control System for a High-Rise Building

Mid-story isolation systems have previously been studied for decrease of the earthquake induced responses of high-rise buildings. The systems have been successfully applied to several buildings in Korea and Japan. Structural designers usually have to ensure that both the peak story and isolator drifts are within permissible limits. However, these two objectives conflict with each other. To solve this problem, a smart mid-story isolation system can be used for tall buildings. The system is composed of rubber bearings and magnetorheological (MR) dampers. The system was employed for an existing structure to reduce both the isolator and story drift. The control efficiency of smart mid-story isolator was evaluated based on a passive system. An artificial seismic load was made for numerical analyses for both systems. A fuzzy soft-computing technique with a multi-objective optimization was adopted to make control algorithm for decrease of both the inter-story and isolator drift. A numerical analysis results presents that the proposed method can effectively decrease the seismic-induced inter-story and isolator drift in the example of a tall building.

Spectrum Analysis-Based Model for the Optimal Outrigger Location of High-Rise Buildings

ABSTRACT The outrigger system is a current alternative to reduce the dynamic response of high-rise buildings. The aim of the study is to develop analytical methods for earthquake response of a conventional outrigger system and to determine the optimal outrigger location. First, a theoretical simplified model is developed based on a dynamic time-history load and is further improved by mode-superposition response spectrum method. The model is then calibrated via an ANSYS model, and the simplified model is applied to perform parametric analyses to acquire the optimal outrigger location of each scheme. Subsequently, all data obtained from parametric analyses are summarized to solve the fitting equation of optimal outrigger location. Finally, a comparison of the results between time-history and spectra analysis suggests that the spectrum analysis-based simplified model effectively simulates the seismic behavior of structure with an outrigger and its corresponding fitting equation reasonably expresses the optimal outrigger location of the aforementioned type of structure under seismic action.

Experimental Verification of Methods for Converting Acceleration Data in High-Rise Buildings into Displacement Data by Shaking Table Test

When diagnosing damage to high-rise buildings during earthquakes, it is necessary to measure the displacement of each story. However, with respect to accuracy and cost, it is most reasonable to convert acceleration into displacement. In this study, shake table testing was carried out to verify the conversion methods, converting the acceleration data measured in a high-rise building into velocity and displacement. In the shaking table test, the displacement of a 10-story model building under strong motion was measured using high-speed imaging devices. High-speed images were taken at 1000 frames per second, reflecting the dynamic behavior of the model building. Then, this displacement was compared with the displacement obtained by processing the acceleration data. This study applied three methods for correcting and converting acceleration into velocity and displacement. Method 1 used the transfer function, H2ω, which reflects the dynamic characteristics of the system. The displacements converted by this method showed the lowest accuracy, because the transfer function depends on the dynamic characteristics of the structure. Method 2 used the cosine Fourier transform for baseline correction, and the discrete input data are calculated as the sum of the cosine functions. Method 3 used the least-squares fitting in the first step to remove the linear drift in the acceleration and applied the high-pass Butterworth filter. The displacements converted by Method 2 were the most reliable, and were close to the displacements measured in the shaking table test. However, the response of high-rise buildings is affected by low- and high-frequency noise. It is necessary to further investigate the limitations and applicability of the conversion methods for providing reliable displacement of the building.

Study of dynamic response of High-Rise buildings under blasting earthquake considering model simplifying

Based on the blasting engineering of the subway tunnel, the overall dynamic response of the 28-story frame-shear-wall structure is studied by field test and numerical analysis. Field test is the blasting vibration monitoring and operational mode analysis (OMA). OMA used Ibrahim Time Domain method to extract the modal frequencies, the modal damping ratio of the structure, provided the basis for further analysis of the vibration response laws. The structure is simplified into a mass-spring-damper model. Based on the modal parameters extracted from the AVT, fixed the stiffness matrix and the damping matrix of the mass-spring-damper model, and set up the dynamic differential equation. So the modal parameters and frequency-response-functions of the building bending vibration can be calculated. SIMULINK dynamic simulation model was established based on the dynamic differential equation of the mass-spring-damper model. Based on the blasting vibration velocity signal, the overall vibration response law of high-rise buildings under tunnel blasting seismic is analyzed. The following conclusions are drawn: 1. Under the blasting vibration of the subway tunnel, the vibration response velocity of high-rise buildings presents: vertical vibration is the largest, lengthways vibration velocity is the second, and transverse vibration velocity is the smallest. However, the vertical vibration velocity peak and tangential vibration velocity peak at the higher floors is not much different. 2. On the higher floors, the velocity peaks fluctuated with floor increasing, and fluctuation is interrelated with the dominant mode. The peak value of vibration velocities distribution shows this correlation; 3, To simplify the high-rise building to be the mass-spring-damper model and set up the mathematical model of dynamic reaction. Then, the Simulink simulation model was established for simulation calculation. This method can adequately predict the response of the structure under blasting vibration.

Analytical Investigation of High Rise Building under Blast Loading

This paper presents the dynamic response of high rise building subjected to blast loading. It is about understanding the explosion phenomena and investigating the dynamic response of a concrete frame structure by using SAP2000. Building is of 10 storey is exposed to 30kg TNT and 60kg TNT with three different standoff distances of 10m, 12.5m and 15m respectively. A non-linear three Dimensional is used for analyzing the dynamic response of a structure. In the present scenario, structures under blast loading (i.e. bomb explosion) are acting in short duration with high pressure intensity of shock wave which is outlined in section of TM-5 1300.The aim of this paper is to investigate the performance of high rise buildings under blast loading, blast phenomena and dynamic response of a concrete frame structure under blast loading by using SAP2000 software. Blasting vibration responses are simulated by using MATLAB program. The result obtained in terms of time history function, displacements and influence of the parameter considering the resistance of structure. Therefore, for decreasing the facade on surrounding buildings, moderate explosive energy is used to control the structural damages due to explosion.

Response of High-Rise Buildings under Long Period Earthquake Ground Motions

Response of High-Rise Buildings under Long Period Earthquake Ground Motions

Wind response of high-rise building in diversified inlets to construct wind turbine system on roof

Many skyscrapers have installed wind turbine systems to use new renewable energy. In particular, building an integrated wind power generation system by installing a wind power generator inside a building is an attractive method to secure safe energy. However, most studies have dealt with the efficiency of wind turbines and the response effects of wind induced vibration; space preparation for wind turbine installations has not been sufficiently considered. This work reviewed the shapes of openings where wind turbines can be installed in skyscrapers, and the characteristics of wind induced vibration responses occurring in the building with changes in cross sectional area. Nine wind power models were constructed to carry out the experiment. According to the experimental results, wind speed varies with shape of opening in the order of C-type>S-type>R-type. Moreover, wind speed increases as the area is reduced.

Vibration control of high-rise buildings for wind: a robust passive and active tuned mass damper

Tuned mass dampers (TMDs) have been installed in many high-rise buildings, to improve their resiliency under dynamic loads. However, high-rise buildings may experience natural frequency changes under ambient temperature fluctuations, extreme wind loads and relative humidity variations. This makes the design of a TMD challenging and may lead to a detuned scenario, which can reduce significantly the performance. To alleviate this problem, the current paper presents a proposed approach for the design of a robust and efficient TMD. The approach accounts for the uncertain natural frequency, the optimization objective and the input excitation. The study shows that robust design parameters can be different from the optimal parameters. Nevertheless, predetermined optimal parameters are useful to attain design robustness. A case study of a high-rise building is executed. The TMD designed with the proposed approach showed its robustness and effectiveness in reducing the responses of high-rise buildings under multidirectional wind. The case study represents an engineered design that is instructive. The results show that shear buildings may be controlled with less effort than cantilever buildings. Structural control performance in high-rise buildings may depend on the shape of the building, hence the flow patterns, as well as the wind direction angle. To further increase the performance of the robust TMD in one lateral direction, active control using LQG and fuzzy logic controllers was carried out. The performance of the controllers is remarkable in enhancing the response reduction. In addition, the fuzzy logic controller may be more robust than the LQG controller.

Influence of Turbulence, Orientation, and Site Configuration on the Response of Buildings to Extreme Wind

Atmospheric turbulence results from the vertical movement of air, together with flow disturbances around surface obstacles which make low- and moderate-level winds extremely irregular. Recent advancements in wind engineering have led to the construction of new facilities for testing residential homes at relatively high Reynolds numbers. However, the generation of a fully developed turbulence in these facilities is challenging. The author proposed techniques for the testing of residential buildings and architectural features in flows that lack fully developed turbulence. While these methods are effective for small structures, the extension of the approach for large and flexible structures is not possible yet. The purpose of this study is to investigate the role of turbulence in the response of tall buildings to extreme winds. In addition, the paper presents a detailed analysis to investigate the influence of upstream terrain conditions, wind direction angle (orientation), and the interference effect from the surrounding on the response of high-rise buildings. The methodology presented can be followed to help decision makers to choose among innovative solutions like aerodynamic mitigation, structural member size adjustment, and/or damping enhancement, with an objective to improve the resiliency and the serviceability of buildings.

Evaluation on Across-Wind Response of Tall Building According to Aerodynamic Shapes

High-rise buildings constructed in large cities are thin and long in their shape and are both unconventional and light-weight. The purpose of this study is to reduce the across-wind response of high-rise buildings (unconventional) under the influence of wind load. As a means to change the external shape of high-rise buildings, we selected the flat Y-type form. It is generally applied in domestic high-rise buildings for examination. Wind tunnel tests take place on 12 high-rise buildings, composed of three different Y-type shapes such as basic square forms with square cross sections and unconventional forms, in a suburban area (α=0.15) with a turbulence intensity of 10%.

Optimal Analysis of High-Rise Building Facade Shape Based on Frequent Earthquake Response

Transfer Matrix Method was used to calculate the frequent earthquake responses of high-rise building with different facade shapes. At the premise of constant lateral rigid and same bottom storey mass and supposing that the facade shape variability is simulated by the change of storey mass, the relationship between the maximum value of seismic response and the structure total mass were obtained. Results show that up concave shapes are more optimal than down concaves, pyramid and homogeneous shape as long as the structure deformation being within a reasonable range. If the building height is the most seeking aspect of the design, an up concave shape should be adopted and the building bottom size can be amplified according to the required architecture scale. On the other hand, up concave shapes can’t adapt to a rather wide range of total mass. If the construction field is limited and the architecture scale must meet the requirement, the homogeneous shape should be adopted.