Systems In High-rise Buildings Research Articles

Investigation of Performance of Soil-Cement Pile in Support of Foundation Systems for High-Rise Buildings

This paper presents the experimental study of Soil-Cement Pile (SCpile) by wet mixing method in sandy soils, with the typical project at An Trung Complex apartment, Da Nang city, Vietnam. With the characteristic of soil layers is sandy soil, the strength of laboratory stabilized soils with the amount of cement from 150¸300 kg/m3 was determined. Simultaneously, the authors also performed the experiments of 20 test piles collected from the site which has cement content about 280 kg/m3 and the unconfined compressive strength qu= (4.5-6.0) MPa. After that, a full-scale model static axial compressive load tests of two single piles and a group of four piles with diameter 800 mm and 12 m length were also conducted. The experiment results show that the bearing capacity of every single pile is 1.200 kN with settlement 6.93 mm and the group of four CSpiles is 3.200 kN with settlement 5.03 mm. The results presented in the paper illustrate that SCpile is the suitable solution for foundation construction process with low cost and saving time for high rise buildings. The result shows a capable application of soil cement piles for support of high-rise buildings.

Suggestions for Developing Integrated Risk Assessment Method for High-Rise Buildings in Korea: Based on Analysis of FEMA’s IRVS

The purpose of this study was to develop the integrated risk assessment system for high-rise buildings reflecting the Korean Building Code and guidelines of Preliminary Disaster Inspection and Consultation Systems based on the analysis of FEMA’s IRVS in US. Through reviewing various hazards’ assessment factors, a classification system and methodology for evaluating risk scores in IRVS, applicable factors, limitation of systems to apply to a Korean future system and improvement to verify the assessment methodology are determined. The results of this study will be used to provide the framework and establish the practical goals for developing a Korean risk assessment system for high-rise buildings.

The influence of fire size on breakage time for double glazed curtain wall system in enclosure fire

The prediction of breakage time on curtain wall system is an important factor for the fire protection system in high-rise buildings. The breakage of glass is caused by thermal deformation of curtain wall frame. Also, thermal deformation could be influence by fire size. Therefore, in this study, numerical analysis is performed to investigate the effect of fire size on breakage time on double glazed curtain wall system. To investigate the effect of fire size on breakage time, the pool size is varied 0.4x0.4 m, 0.5x0.5 m and 0.6x0.6 m, respectively. As a result, the breakage times of glass are decreased as 170 s, 100 s and 38 s for the pool size varying 0.4x0.4 m, 0.5x0.5 m and 0.6x0.6 m, respectively. From the numerical results, the present study suggests the useful relationship between the heat release rate and breakage times as follow: t = -0.341×Q e + 257.64 (252.3 kw < Q e < 637.9 kw). In order to prevent breakage of glass curtain wall due to fire, fire protection system must be operated

Fire Extinguishing System for High-Rise Buildings and Rugged Mountainous Terrains Utilizing Quadrotor Unmanned Aerial Vehicle

Fire Extinguishing System for High-Rise Buildings and Rugged Mountainous Terrains Utilizing Quadrotor Unmanned Aerial Vehicle

Variation principle in calculating the flow of a two-phase mixture in the pipes of the cooling systems in high-rise buildings

The analytical solution of one of the urgent problems of modern hydromechanics and heat engineering about the distribution of gas and liquid phases along the channel cross-section, the thickness of the annular layer and their connection with the mass content of the gas phase in the gas-liquid flow is given in the paper.The analytical method is based on the fundamental laws of theoretical mechanics and thermophysics on the minimum of energy dissipation and the minimum rate of increase in the system entropy, which determine the stability of stationary states and processes. Obtained dependencies disclose the physical laws of the motion of two-phase media and can be used in hydraulic calculations during the design and operation of refrigeration and air conditioning systems.

Design of solar systems in high-rise buildings

Nowadays, the renovation program is being implemented in the megapolises of Russia. Innovative high-rise buildings are built instead of morally and physically obsolete houses, where non-traditional renewable energy sources are used to the fullest extent, under the effect of which they are located. The possibility to use solar systems with variation of their design parameters is considered. It is established that solar systems have high technical potential. The share of heat load, that is provided by using solar energy, varies from 4 to 84% depending on the time of the year. Economic indicators restrain the use of such panels. The payback period is about 8 years at the current cost for thermal energy.

Calculation of critical heat transfer in horizontal evaporator pipes in cooling systems of high-rise buildings

An exact calculation of the heat exchange of evaporative surfaces is possible only if the physical processes of hydrodynamics of two-phase flows are considered in detail. Especially this task is relevant for the design of refrigeration supply systems for high-rise buildings, where powerful refrigeration equipment and branched networks of refrigerants are used. On the basis of experimental studies and developed mathematical model of asymmetric dispersed-annular flow of steam-water flow in horizontal steam-generating pipes, a calculation formula has been obtained for determining the boundaries of the zone of improved heat transfer and the critical value of the heat flux density. A new theoretical approach to the solution of the problem of the flow structure of a two-phase flow is proposed. The applied method of dissipative characteristics of a two-phase flow in pipes and the principle of a minimum rate of entropy increase in stabilized flows made it possible to obtain formulas that directly reflect the influence of the viscous characteristics of the gas and liquid media on their distribution in the flow. The study showed a significant effect of gravitational forces on the nature of the phase distribution in the cross section of the evaporative tubes. At a mass velocity of a two-phase flow less than 700 kg / m2s, the volume content of the liquid phase near the upper outer generating lines of the tube is almost an order of magnitude lower than the lower one. The calculation of the heat transfer crisis in horizontal evaporative tubes is obtained. The calculated dependence is in good agreement with the experimental data of the author and a number of foreign researchers. The formula generalizes the experimental data for pipes with the diameter of 6-40 mm in the pressure of 2-7 MPa.

Fire safety issues in the design and construction of high-rise buildings

The construction of high-rise buildings has revealed new problems related to fire safety. The peculiarity of the architecture, which is covered in high-rise, in fires creates a danger for a large number of people there, reduces the possibility of their evacuation and rescue. The multifunctionality of such buildings, taking into account the originality of the external and internal views, leads to the difficulty of choosing a constructive system, a large number of utilities and technical systems. To address the issues related to safe operation, stay and evacuation of people is the development of a fire protection system for high-rise buildings, based on the development of: • measures to ensure the durability of buildings or parts thereof againstprogressive collapse due to * ensuring the fire resistance of structures and buildings; • measures to limit the spread of fire in high-rise buildings through theinstallation of fire barriers inside the building and the device of fire breaks between buildings; • measures for ensuring timely and unimpeded evacuation of people andtheir rescue at emergency in high-rise buildings; • systems of active protection of buildings from fire, namely: fire alarm andfire fighting, strong points of fire extinguishing.

Constructive systems, load-bearing and enclosing structures of high-rise buildings

As the height of the building increases, loads on load-carrying structures increase dramatically, and as a result of the development of high-rise construction, several structural systems of such buildings have been developed: frame, frame-frame, cross-wall, barrel, box-type, box-to-wall ("pipe in pipe", "Trumpet in the farm"), etc. In turn, the barrel systems have their own versions: cantilever support of the ceilings on the trunk, suspension of the outer part of the overlap to the upper carrying console "hanging house" or its support by means of the walls on the lower bearing cantilever, intermediate position of the supporting cantilevers in height to the floor, from a part of floors. The object of the study are the structural solutions of high-rise buildings. The subject of the study is the layout of structural schemes of high-rise buildings, taking into account the main parameters - altitude (height), natural climatic conditions of construction, materials of structural elements and their physical and mechanical characteristics. The purpose of the study is to identify the features and systematization of structural systems of high-rise buildings and the corresponding structural elements. The results of the research make it possible, at the stage of making design decisions, to establish rational parameters for the correspondence between the structural systems of high-rise buildings and their individual elements.

Effect of changing of the parameters of the cable network of monitoring systems of high-rise buildings on the basis of string converters on their operability

The article is devoted to the problem of improving the reliability of monitoring systems for the technical conditions of high-rise buildings. The improvement is based on string sensors with an impulsed excitation method ensuring the maximum signal-to-noise ratio at their output. The influence of the parameters of the monitoring system on the shape of the excitation impulses of the string, and, consequently, on the amplitude of the string vibration of the string converter is also considered in the article. It has been experimentally proved that the parameters of the excitation impulses of the string converters. The article presents the results of the experiments showing the effect of the fronts duration of the excitation impulses on the amplitude of the oscillations of the strings. The influence of the fronts duration of the excitation impulse with the frontal lengths up to 0.5 ms is studied at the excitation impulse duration not exceeding 0.5 times the duration of natural oscillation periods of the string. The experimental data are compared with the theoretical ones and hypotheses explaining their difference are advanced. The article suggests some methods of reducing the influence of the cable-switching equipment system parameters on the amplitude of string oscillations. The possibilities of improving the reliability of the systems developed on the basis of string sensors with an impulsed excitation method and used for monitoring the technical conditions of the high-rise buildings are proposed.

Analytical Investigation of the Applicability of Seismic Devices for Core Frames System in High-Rise Buildings

The use of link element in high rise buildings has been applied widely and proven to be effective in the eccentric braced frame system. Latest research has also shown that the applicability of link element can be extended to other type of structural systems, such as: coupled wall system or structures with core wall. The research showed that the use of link element could lead to better deformation capacity of the system and the link elements could act as a “fuse” to limit the input of earthquake force. However, the improvement of the seismic behavior may not be effective for any type of structural system. This paper investigates analytically parameters affecting the effectiveness of the application of shear link elements within a structural system. Several parameters being studied are the relative stiffness between link element and structural stiffness, types of structural configuration, etc.

Numerical Analysis of Reinforced Concrete Piles under Blast Loads

Pile foundations are commonly used as foundation systems for high-rise buildings and bridges. This paper uses a fully coupled three dimensional numerical modelling procedure to study the performance of pile foundations subjected to ground shocks induced by surface explosions. The comprehensive numerical model includes the pile, surrounding soil, air and the explosive. Appropriate material models are incorporated and dynamic non-linear analysis is carried out using finite element techniques. The soil in which the pile is buried could influence the blast performance of the pile. A parametric study is hence carried out to evaluate the effects of soil properties of density, friction angle, cohesion and Poisson’s ratio on the blast performance of the pile. It is found that density and cohesion of soil have significant effects on the deflection of the pile under blast loading. Poisson’s ratio has some effect, but effect of the soil friction angle is not very significant. The findings of this study will serve as a benchmark reference for future analysis and design of pile foundations to blast loading.

Calibration of Parameters for Predicting Hysteretic Behavior of Diagonally Reinforced Concrete Coupling Beams

The coupled shear wall system with coupling beams is an efficient structural system for high-rise buildings because it can provide excellent ductility and energy dissipation to the buildings. The objective of this study is to simulate the hysteretic behavior of diagonally reinforced concrete coupling beams including pinching and cyclic deteriorations in strength and stiffness using a numerical model. For this purpose, coupling beams are modeled with an elastic beam element and plastic spring element placed at the beam ends. Parameters for the analytical model was calibrated based on the test results of 6 specimens for diagonally reinforced concrete coupling beams. The analytical model with calibrated model parameters is verified by comparing the hysteretic curves obtained from analysis and experimental tests.

Fire Safety and Security System in High-rise Buildings in Tangail Pourashava

Fire safety and security system in high-rise buildings has been a significant issue from the last century. However, there are numerous provisions for safety measures from such fires and the magnitude and nature of the problem of this hazard has been unknown. This study identifies the location of high-rise buildings in Tangail pourashava through an extensive survey and then identifies the unique fire safety problems of those buildings and their associated fire risk. As it turns out, most of those buildings are highly vulnerable to fire risk due to lack of major fire fighting equipments and defiance of related laws and regulations. The study then addresses the means to provide fire safety in those buildings from both design and codes perspectives. It elaborates on the need to provide both building and occupant based protection to achieve the best results. It concludes with an overview of the special problems associated with high-rise buildings combined with specific use and occupancy-related requirements, employee training and response.J. Environ. Sci. &amp; Natural Resources, 10(1): 33-40 2017

Experimental Study of T-Shaped RC Shear Wall Subjected to Cyclic Loading

Shear wall systems are one of the most commonly used lateral load-resisting systems in high-rise buildings. Traditionally, high–thickness ratio of RC shear wall is larger than 8. To investigate the seismic performance of a T-shaped shear wall structure, a total of nine 1/2-scaled models were tested under cyclic loading. The variation of high–thickness ratio was from 4 to 9. All models were loaded in the web, except one specimen loaded in the flange. The axial load ratio was in the range from 0.1 to 0.3. The failure process, failure mode and deformation properties of the specimens were presented herein. The test results showed that the T-shaped shear walls had better ductility than traditional RC shear walls. Meanwhile, the ductility of the model did not change consistently with the axial load ratio and high–thickness ratio. Further, the best seismic performance was achieved when the axial load ratio and high–thickness ratio were within a certain range. The ductility and energy dissipation capacity of the specimen with axial load ratio of 0.2 and high–thickness ratio of 6.5 were the best.

Hydraulic Control Method for Heating Systems of High-Rise Buildings

The following article reflects the ideas of possibility to increase energy efficiency of heating systems in high-rise buildings. The article also includes the principle ways of high-rise building heating systems operation as well as traditional engineering decisions aimed at the elimination of the increased pressure effect in heaters. The main disadvantages of such decisions are also presented for the reader. Moreover, the article offers the way of operation for the above-mentioned systems together with the equipment that implements this operation. An economic impact from such energy-saving technology application has been also evaluated.

Outrigger tuned inertial mass electromagnetic transducers for high-rise buildings subject to long period earthquakes

This paper proposes outrigger tuned inertial mass electromagnetic transducer (TIMET) systems for high-rise buildings subject to long period earthquake excitations. The proposed outrigger TIMET systems consist of the outrigger and TIMET parts. The outrigger damping systems have been proposed as a novel energy dissipation approach to high-rise buildings, in which control devices are installed vertically between the outrigger and perimeter columns to achieve large energy dissipation. While the TIMET has been developed based on the mechanism of the tuned viscous mass damper (TVMD) which can improve energy absorbing capability by taking advantage of resonance effect. However, instead of a viscous material, the damping of the TIMET is provided by a motor which can convert mechanical energy to electrical energy. The focus of this study is to investigate the structural control performance and energy harvesting efficiency of the proposed outrigger TIMET system for high-rise buildings subjected to long period earthquakes through numerical simulations.

11.43: Seismic performance of staggered steel plate shear wall systems in high rise buildings

ABSTRACTUnstiffened Steel Plate Shear Walls (SPSWs) are used as the lateral load‐resisting systems in building structures. The energy dissipation mechanism of SPSWs is consisted of the tension yielding of web plates and the formation of plastic hinges at the ends of horizontal boundary elements (HBEs). High‐rise buildings experience the high overturning moments leading to the high axial demands in the vertical boundary elements (VBEs) of SPSWs. The presence of high axial forces in VBEs can cause a reduction in their flexural capacity resulting in the drift concentration or even soft‐story mechanisms in the lower storey levels during an earthquake event. Past studies have shown that a staggered arrangement of steel plates may help in reducing the force demand in VBEs. Two simple methods are investigated in this study to r b educe the VBE forces are (i) by increasing the width of the web plates and (ii) by staggering the web plates over the frame height. A 20‐story steel frame building has been considered as the study frame. Three types of systems are designed to study the effect of aspect ratio and staggering on the seismic behaviour of SPSW. Force‐displacement characteristic of SPSW used in the numerical model is validated with the test results. Both nonlinear static and dynamic analyses are carried out in this study. Axial and shear force demands in the VBEs are reduced for the study frame, while achieving the desired hinge mechanisms. Nonlinear dynamic analyses under twenty spectrum‐compatible design‐level ground motions exhibited that staggered steel plate shear wall systems reduced the inter‐story drift by about 50% with respect to their conventional counterpart.

A-35 高層建物のループ通気方式の排水能力の把握と予測手法に関する研究 : その4. ループ通気管多数箇所設置方式の検討

A-35 高層建物のループ通気方式の排水能力の把握と予測手法に関する研究 : その4. ループ通気管多数箇所設置方式の検討

A-34 高層建物のループ通気方式の排水能力の把握と予測手法に関する研究 : その3. ループ通気管2箇所設置方式の検討

A-34 高層建物のループ通気方式の排水能力の把握と予測手法に関する研究 : その3. ループ通気管2箇所設置方式の検討