Design Of High-rise Structures Research Articles

Performance evaluation of high-rise reinforced concrete buildings under dynamic loading considering different structural systems

With the growing construction of towering structures owing to modernisation and growth in land use, tackling the height and stiffness concerns are now essential. Several structural systems have been developed to withstand various loading scenarios, including framed systems, shear wall systems, braced framed systems, outrigger systems, and diagrid systems. The present investigation employs E-tabs software to accomplish dynamic analyses on a G + 16 story RCC building with regard to every structural system. The variables studied were base shear values, storey shear force values, maximum displacement values, maximum storey drift values, stiffness of storey levels, and time periods. The major goal was to find the most appropriate system among those examined. This study can add to our knowledge concerning building dynamics and helps to make well-versed assessments about prospective high-rise constructions and the findings can be useful in the design of high-rise structures. After accomplishing the study, it was demonstrated that for numerous response parameters, the diagrid structural system proved to be the most successful in managing lateral forces, functioning similarly to the shear-walled model. The diagrid structural system's efficiency in optimising stability and resistance against dynamic loads demonstrates its potential for improving the safety as well as the performance of these structures. Finally, the diagrid system offers potential as a feasible high-rise building choice, providing an efficient and effective response to the issues faced by urbanization-driven vertical expansion.

Investigation of Linear Dynamic Analysis and Duc-tile Design of High Rise Structure as per Revised Indian Code

Abstract: This thesis gives a comparative seismic analysis of high rise structure in zone III and zone IV using the New IS 13920- 2016 standards. The recent earthquakes in India revealed unequivocally that conventional structural design and construction techniques fail to meet fundamental seismic resistance standards. The use of ductile design and detailing methods in conventional construction is a critical topic that requires attention. The ductility of reinforced concrete structures as a whole is a difficult topic. However, specific design factors and reinforcing details may be used in particular critical spots of the building structure to reduce seismic damage and life-threatening collapse. The approaches are straightforward, affordable, and extensively detailed in the Indian Bureau of Standard Code of Practice's standard code of practise (IS13920). It is recommended to conduct a comparative analysis of the dynamic behaviour of high-rise structures using the response spectrum approach in accordance with IS 1893 Part1-2016 The investigation of characteristics including displacement, base shear, and tale drift. Examining factors including modal frequencies and acceleration in response spectrum load instances in both the X and Y directions. Ductile design of high rise structures in accordance with IS 13920-2016's new codal requirements. Additionally, it is recommended to analyse and design multi-story buildings using computational software such as ETABS and compare characteristics such as storey displacement, base shear and storey drift. The shear wall at the corner reduces storey X displacement by 46.245%. The intermediate shear wall reduces displacement by 54.617%. The central shear wall reduces displacement by 68.72%. Lower level shear wall displacement is central. Shear wall at corner reduces storey drift in X direction by 49.374%. Shear wall at centre reduces drift by 39.716%. Shear wall at centre reduces drift by 2.638%. Lower story drift in central shear wall. Shear wall at corner base shear drift is 63.646% greater than without shear wall. Base shear is 64.006% higher with a middle shear wall. Shear wall at the centre increases base shear by 65.765%. Center shear wall has stronger base reaction.

Aerodynamic study of tall buildings under wind load

In Design of high-rise structures, Wind is considered as one of the important horizontal forces that have significant impact on the response of building. Due to rise in population, the demand for tall buildings is increasing day by day. Wind Load on such structures are calculated using pressure coefficients and force coefficients which are available in various international codes and standards. However, these international codes and standards give information about regular shape buildings such as square, rectangle, circular or octagonal.With the technological advancement, composite plan shape buildings such as square and circular, circular and hexagonal and square and octagonal etc. have been considered by many architects keeping in view of aesthetics of Building. The wind flow around a tall building with composite plan shapes having different height ratio variation differs from what we get in regular shape analysis. Since, data is not available regarding such buildings, the need to carry wind tunnel testing or CFD become important for analyzing wind effect on such buildings. CFD (Computation Fluid Dynamics) for determining wind responses is becoming immensely popular.

EXPERIMENTAL STUDY ON BEHAVIOR OF UNPROTECTED FOAMED CONCRETE FILLED STEEL HOLLOW COLUMN UNDER FIRE

Reduction in self-weight and achievement of full fire resistance requirements are some of the important considerations in the design of high-rise structures. Lightweight concrete filled steel tube (CFST) column provides an alternative method to serve these purposes. Recent studies on lightweight CFST columns at ambient temperature have revealed that foamed concrete can be a beneficial and innovative alternative material. Hence, this study investigates the potential of using foamed concrete in circular hollow steel columns for improving fire resistance. A series of nine fire test on circular unfilled hollow and foamed concrete filled hollow section column were carried out. ISO 834 standard fire exposure test were carried out to investigate the structural response of these columns under fire. The main parameters considered are load level and foamed concrete density; foamed concrete density used are 1500 kg/m3 and 1800 kg/m3 at 15%, 20%, and 25% load level. All the columns tested are without any external fire protection, with concentrically applied load under fixed-fixed boundary conditions. The columns dimension was 2400 mm long, 139.7 mm diameter and steel tube thickness of 6 mm. The fire test result showed that foamed concrete increases the fire resistance of steel hollow column up to an additional 16 minutes. The improvement is more at load level above 15%, and the gain in fire resistance is about 71% when 1500 kg/m3 density foamed concrete is used. Generally, foamed concrete filled steel hollow column demonstrate a good structural fire behavior, based on the applied load and foamed concrete density. Also, inward local buckling was averted by filling the steel hollow column with foamed concrete. General method for composite column design in Eurocode 4 adopted to calculate the axial buckling load of 1500 kg/m3 foamed concrete filled columns. These type of columns can be used for structures like airports, schools, and stadiums; taking the advantage of exposed steel for aesthetic purpose and high fire resistance. It can also be used for high rise structures; taking advantage of high fire resistance and reduction in self-weight of a structure.

Tensile Strength Characterization of Quenched and Self-Tempered (QT/TMT) Reinforcing Coupled and Welded Steel Bars

Considering that the Philippines located in Seismic Zone 4, concrete structures are commonly reinforced using reinforcing steel bars, or commonly referred to as rebars. The production of rebars is limited to certain lengths like 6.0m, 7.5m, 9.0m, 10.5m and 12.0m and mostly are produced using quenched and tempering process. These rebars are commonly referred to as Quenched Tempered Thermo-Mechanically Treated (QT/TMT) Steel Reinforcing Steel Bars. This study concentrated on this kind of rebars. The concerns of structural builders and manufacturers arise when design of high-rise structures is involved, particularly those employing the process of joining QT/TMT rebars to meet the required design heights. When QT/TMT rebars are subjected to various joining or coupling process, the mechanical properties are affected, thus, influencing the structural integrity of the design. This study considered six kinds of joining process of rebars, where each one was subjected to tensile test, hardness test, chemical analysis and micro- examination to determine the tensile characteristics after undergoing a certain joining procedure. Samples were taken from three major QT/TMT rebar manufacturing companies in the Philippines through the coordination from the Bureau of Philippine Standards. The tensile tests were conducted using a Universal Testing Machine while chemical analysis used an Optical Emission Spectrometer. The results showed that out of six kinds of joining process, only two complied with the technical requirements of PNS 49: 2002 in terms of Tensile Strength, Yield Strength, Percent Elongation and TS/YS Ratio. Micro-examination was performed on several samples to determine how the tempered martensite regions were affected by the joining process used which eventually affected the mechanical properties.

EFFECT OF SHEAR WALL ON PERFORMANCE OF MULTISTOREY BUILDING

Seismic force, predominantly being an inertia force depends on the mass of the structure. As the mass of the structure increases the seismic forces also increase causing the requirement of even heavier sections to counter that heavy forces. And these heavy sections further increase the mass of the structure leading to even heavier seismic forces. Structural designers are met with huge challenge to balance these contradictory physical phenomena to make the structure safe. The structure no more can afford to be rigid.
 This introduces the concept of ductility. The structures are made ductile, allowing it yield in order to dissipate the seismic forces. A framed structure can be easily made ductile by properly detailing of the reinforcement. But again, as the building height goes beyond a certain limit, these framed structure sections (columns) gets larger and larger to the extent that they are no more practically feasible in a structure. There comes the role of shear walls. Shear walls provide ample amount of stiffness to the building frame resisting loads through in plane bending. But they inherently make the structure stiffer. So, there must be a balance between the amount of shear walls and frame elements present in a structure for safe and economic design of high-rise structures.
 Here an attempt has been made to study the behavior of different structures of reinforced concrete with different heights with and without shear walls. Coupled shear walls have also been studied to understand the comparative merit or demerit of framed structures with shear wall structures. Studies have been carried out on sample model structures and analysis has been carried out by ETABS software. It has been ensured to consider sample models that represent the current practices in structural design to include different structural configurations. Models having varied structural configurations like framed, shear wall, coupled shear wall, central core shear wall, core in core etc. have been taken into consideration. The inherent asymmetry present in the structures have also been dealt.
 The results have been tabulated and plotted to study their comparative behavior and interaction with each other. The findings of the study have been summarized and discussed.

Retraction Notice: Performance Analysis of Key Joints and Seismic Design of High-rise Structures

Retraction Notice: Performance Analysis of Key Joints and Seismic Design of High-rise Structures

Equivalent static wind loads analysis of tall television towers considering terrain factors of hilltops based on force measurement experiment

Wind field in mountainous regions demonstrates unique distribution characteristic as compared with the wind field of the flat area, wind load and wind effect are the key considerations in structural design of television towers situated in mountainous regions. The television tower to be constructed is located at the top of Xiushan Mountain in Nanjing, China. In order to investigate the impact of terrain factors of hilltops on wind loads, firstly a wind tunnel test was performed for the mountainous area within 800m from the television tower. Then the tower basal forces such as bending moments and shear strength were obtained based on high frequency force balance (HFFB) test. Based on the experiments, the improved method for determining the load combinations was applied to extract the response distribution patterns of foundation internal force and peak acceleration of the tower top, then the equivalent static wind loads were computed under different wind angles, load conditions and equivalent goals. The impact of terrain factors, damping ratio and equivalent goals on the wind load distribution of a television tower was discussed. Finally the equivalent static wind loads of the television tower under the 5 most adverse wind angles and 5 most adverse load conditions were computed. The experimental method, computations and research findings provide important references for the anti-wind design of high-rise structure built on hilltops.

Comprehensive Analysis on Seismic Design of Tall Building Structure Method

<p class="ordinary-outputtarget-output">For a high-rise structure design, the problems encountered may be perplexing, concrete analysis of concrete problems only. Engineering practice shows that the design process of the high-rise structure, design personnel only seismic conceptual clarity, structure measure analysis software three organic combinations to achieve more satisfactory results in the process of seismic structural weight in structure calculation structure properly applying the appropriate. This paper makes a theoretical analysis of necessity for building seismic design concept, in order to explore the method of high-rise building to take the necessary anti-seismic measures.</p>

Wind profiles of tropical cyclones as observed by Doppler wind profiler and anemometer

This paper investigates the vertical profiles of horizontal mean wind speed and direction based on the synchronized measurements from a Doppler radar profiler and an anemometer during 16 tropical cyclones at a coastal site in Hong Kong. The speed profiles with both open sea and hilly exposures were found to follow the log-law below a height of 500 m. Above this height, there was an additional wind speed shear in the profile for hilly upwind terrain. The fitting parameters with both the power-law and the log-law varied with wind strength. The direction profiles were also sensitive to local terrain setups and surrounding topographic features. For a uniform open sea terrain, wind direction veered logarithmically with height from the surface level up to the free atmospheric altitude of about 1200 m. The accumulated veering angle within the whole boundary layer was observed to be 30o. Mean wind direction under other terrain conditions also increased logarithmically with height above 500 m with a trend of rougher exposures corresponding to lager veering angles. A number of empirical parameters for engineering applications were presented, including the speed adjustment factors, power exponents of speed profiles, and veering angle, etc. The objective of this study aims to provide useful information on boundary layer wind characteristics for wind-resistant design of high-rise structures in coastal areas.

FKM-Based Clustering Case Retrieval of the High-Rise Building Structural Intelligent Scheme Design

Firstly, the disadvantage of the traditional "hard clustering" was analyzed; and the basic principles and algorithm steps of the fuzzy clustering was presented, it can express and process the class of objects which is not clearly in nature. Secondly, the theory and cluster analysis method is introduced to design high-rise structure; based on the fuzzy K-Means clustering analysis, the case retrieval method of the high-level structural intelligent design was established. Lastly, the example of engineering application was given in where the 26 projects data was used as the basis for the cluster and instance retrieval; the former 20 data is used to cluster and the last 4 data used to instance retrieval, the clustering member is k=4. Practice shows that the fuzzy k-means cluster analysis method is effective for the intelligent design of high-rise structure to obtain an instance, and opens up new ways and means for the high-rise building intelligent design.

The Conceptual Design of High-Rise Structures

In this paper, the contents, meaning and importance of conceptual design in the high-rise building structure design are explored from the following respects: structural system, facade layout and multi-channel seismic line. It not only provides a strong protection of concept for calculation of high-rise building structures, but also accumulates some experience for the research on conceptual design of high-rise structures.

Direct Displacement Based Seismic Design of High Rise Structures with Strengthened Stories (II) - Application

Based on mechanical characteristics of high rise structures with strengthened stories, the author performed direct displacement based seismic design on a high rise structure with 2 strengthened stories according to the direct displacement based seismic design principle. The performance levels are set to be “serviceability” under medium earthquake and “life safety” under major earthquake, respectively. The design procedures are with the following features: (1) Definition and selection of “key” stories are based on mechanical characteristics of high rise structures with strengthened stories; (2) Determination of mode number and calculation of horizontal earthquake action verified the availability of the design procedure; (3) some new ideas are proposed to improve the earthquake action calculation and structural performance control. The design procedure verified the effectiveness, feasibility and availability of the proposed direct displacement based seismic design method.

Direct Displacement Based Seismic Design of High Rise Structures with Strengthened Stories (I) - Theory

High rise structures with strengthened stories are widely used nowadays. A rational seismic design procedure for this kind of structure is thus necessary. Based on mode theory and direct displacement based seismic design of multi-story buildings, this paper proposed a new direct displacement based seismic design procedure. In the proposed method, each mode of the high rise structure is equivalent to a single degree of freedom (SDOF) system. Seismic response of each mode is calculated and adds up to consider the contributions of higher modes. Considering the characteristic of strengthened stories, two stories above the strengthened stories are taken as the “key stories”, whose performance indicates the performance of the building. The proposed procedure is logical, simple and can serve for reference of actual design.

Wind Loads Simulation of Tall Building Structure Subjected to Wind-Structure Interaction

Wind is an important and complex load and an important basis in the structural analysis and the design of high-rise structure. Based on Davenport wind spectrum, multi-dimensional fluctuating wind and random wind load of tall building structure are simulated by using harmonic wave superposition method. To investigate the coupling effect of wind loads, wind-structure system is solved with Wilson-θ step-by-step numerical integration method, and the wind load of Tall building structure subjected to fluid-structure interaction. Turbulence intensity and its variation are presented in this paper.

Tower and office: from modernist theory to contemporary practice

In Tower and Office, Spanish architects Inaki Abalos and Juan Herreros look at the role and impact of advanced building technologies in American architecture since World War II. The war, they claim, marked the end of the first cycle of modernism, challenging the belief that technological progress alone could produce a perpetually better future. At the same time, the war was the source of powerful new structural models and construction methods. The authors examine the ways these technologies have been inflected over the last half century by more subjective and integrated processes of spatial organization.In the first part of the book, Abalos and Herreros focus on the work of Le Corbusier, revealing the degree of complexity achieved in his interpretation of the modern skyscraper. In the second part, they look at the intersection of technical and cultural determinants in the design of high-rise structures since World War II. Among the issues they consider are the evolution of the load-bearing frame, the impact of high-tech systems on tall buildings, and the transparent building skin. In the third part, they address developments in office design and planning, tracing an evolution from the repetitive and homogeneous office skyscraper to the present-day mixed-use structure. Overall they demonstrate how the objective technical analysis associated with modernist architectural theory has given way in recent building practice to a variety of flexible, pragmatic, and environmental approaches. These, they suggest, have opened the way to new urban and architectural forms.

Optimum Belt Truss Locations for High-Rise Structures

Innovative structural schemes are continuously being sought in the design of high-rise structures with the intention of limiting the wind drift to acceptable limits without paying a high premium in steel tonnage. The savings in steel tonnage and cost can be dramatic in high-rise buildings if certain techniques are employed to utilize the full capacities of the structural elements. Various wind bracing techniques have been developed to this end; this paper deals with one such system, namely, the belt truss system. A method of analysis is presented for obtaining optimum combination of belt truss location which minimizes the wind drift of the building.