Systems In High-rise Buildings Research Articles

COSMO—Software for designing smoke control systems in high-rise buildings

A differential computer model specifically designed to quantify smoke movement during a fire in a high-rise structure is described. The basic conservation equations are transformed into a computer code which can be used to determine the paths that smoke will take during a fire. The program is a tool for fire protection engineers to design a smoke management plan with the ultimate goal of improving occupant safety in the event of a fire. The computer code is based on a modified and improved differential smoke control model for the conditions in the floor spaces, stairwells and elevator shafts and it considers a complete set of variables that influence the motion of smoke throughout the building. Program output suggests ways to alter the pressure distribution within the building by using air handling equipment, so that occupants will have smoke-free areas on the floors and inside of the fire escape stairwells. Results for several example cases are provided, and the results are used to illustrate how smoke movement can be managed in order to mitigate dangerous conditions within the building.

Seismic behaviour of composite shear walls with multi‐embedded steel sections. Part I: experiment

AbstractShear wall system is one of the most commonly used lateral load‐resisting systems in high‐rise buildings. The reinforced concrete (RC) walls studied herein are composite shear walls (CSW) with multi‐embedded steel sections (MSS) at wall boundaries as well as wall middles. In this paper, experimental studies of CSW with MSS are presented and discussed. Sixteen 1/3‐scale specimens with varied structural parameters were tested under static loading and the effects of the parameters on the seismic performance of CSW were studied. It is found that the practice of MSS in RC walls is a good way to improve the structural ductility. CSW with MSS has better energy dissipation capacity than that with steel sections only at boundaries. MSS did not affect the final failure mode of the CSW, but they would restrain the development of cracks and prevent the concrete from serious spalling. For MSS, more steel area configured at the end columns will result in better seismic behaviour of CSW. Copyright © 2010 John Wiley & Sons, Ltd.

RESTORING FORCE CHARACTERISTICS OF ULTRA-HIGH-STRENGTH SHEAR WALLS

A high-rise building system with reinforced concrete shear walls makes flexible planning possible, since the shear wall can bear most of seismic force and relieve the load of columns. Lateral and axial loading tests on the reinforced concrete shear wall with 120N/mm2 compressive strength concrete had been conducted. The test results reveal that its structural performance is greatly affected by axial compression behavior of the local compression zone in the shear wall.3D frame analysis is a valuable method to estimate the earthquake response of high-rise buildings. In this paper, 3D analytical models of the shear walls with ultra-high-strength concrete have been investigated, which can represent its compressive failure.

Indoor and outdoor PM 2.5 and PM 10 concentrations in the air during a dust storm

Asian dust storms (ADS) originating from the arid deserts of Mongolia and China are a well-known springtime meteorological phenomenon throughout East Asia. The ventilation systems in office utilize air from outside and therefore it is necessary to understand how these dust storms affect the concentrations of PM 2.5 and PM 10 in both the indoor and outdoor air. We measured dust storm pollution particles in an office building using a direct-reading instrument (PC-2 Quartz Crystal Microbalance, QCM) that measured particle size and concentration every 10 min for 1 h, three times a day. A three-fold increase in the concentrations of PM 2.5 and PM 10 in the indoor and outdoor air was recorded during the dust storms. After adjusting for other covariates, autoregression models indicated that PM 2.5 and PM 10 in the indoor air increased significantly (21.7 μg/m 3 and 23.0 μg/m 3 respectively) during dust storms. The ventilation systems in high-rise buildings utilize air from outside and therefore the indoor concentrations of fine and coarse particles in the air inside the buildings are significantly affected by outside air pollutants, especially during dust storms.

Middle-Story Isolated Structural System of High-Rise Building

For buildings of normal earthquake-resistant construction, it is essential to provide their structural frame with sufficient rigidity and strength horizontally and vertically, ensuring a uniform distribution of rigidity and strength in the plane. To this end, it is typical that those buildings adopt the same type of construction and structural system. On the other hand, in buildings of general base-isolation construction, their upper structure, which is supported by a base isolation layer, undergoes lessened seismic forces and therefore is able to tolerate concentration of rigidity and strength. This makes them available for construction with any types of structural systems, which in turn allows new structural planning realizing a greater freedom in architectural design; the same type of construction and structural system for the upper structure is generally adopted. In contrast, when a high-rise building is provided with an isolation layer in an intermediate level, its upper structure, which is placed above the isolation layer, has high seismic resistance as a seismic isolation structure. And a mass damper effect contributes to decrease in seismic responses in the lower structure, ensuring high seismic resistance of a building. This paper describes the physical properties of a seismic isolation layer system which is built at an middle-story of a building. It also introduce buildings by which potentials for new architectural planning are proposed through the use of this system.

Seismic behaviour of concrete-filled steel tubular frame to RC shear wall high-rise mixed structures

Composite frames consisting of concrete-filled steel tubular (CFST) columns and steel beam are being used more and more popularly in building structures. In China, the composite frame structures are often mixed with reinforced concrete shear walls to form a high-rise building system. However, there was seldom information on the seismic performance of this kind of mixed construction. Shaking table tests on two building models with 30 storeys consisting of composite frames and RC shear walls were thus presented in this paper. CFST columns with circular and square sections were used in the composite frames respectively. Three kinds of real earthquake records, including Taft (EW), El Centro (NS) and Tianjin waves with peak accelerations of 0.2 g , 0.4 g , 0.6 g , and 0.8 g , were applied respectively to simulate different levels of earthquakes in the tests. It was found that the composite frames cooperated well with the core RC shear wall structure under earthquakes, and the two building models exhibited excellent seismic performance.

A Study of Double-Deck Elevator Systems Using Genetic Network Programming with Reinforcement Learning

In order to increase the transportation capability of elevator group systems in high-rise buildings without adding elevator installation space, double-deck elevator systems (DDES) is developed as one of the next generation elevator group control systems. Artificial intelligence (AI) technologies have been employed to find some efficient solutions in the elevator group control systems during the late 20th century. Genetic Network Programming (GNP), a new evolutionary computation method, has been employed as the elevator group control system controller in some studies of recent years. Moreover, reinforcement learning (RL) has been also found to be useful for more improvements of elevator group control performances when it is combined with GNP. In this paper, we proposed a new approach of DDES using GNP with RL, and did some experiments on a simulated elevator group control system of a typical office building to evaluate its applicability and efficiency. Simulation results show that the DDES using GNP with RL performs better than the one without RL in regular and down-peak time, while both of them outperforms a conventional approach and a heuristic approach in all three traffic patterns.

Algorithm for Controlling Multi-Car Elevator Systems Based on Procedures Estimating Efficiency of Passenger Transport and Call Assignability

Recently multi-car elevator (MCE) consisting of several elevator cars in a single elevator shaft received great interest as transportation systems for high-rise buildings. Algorithms for efficiently controlling elevator cars are necessary to put MCEs to practical use. We propose an algorithm for controlling MCEs to reduce passenger-waiting time. A feature of our algorithm is the introduction of a simple function estimating efficiency of passenger transport and a procedure checking assignability of a car. We evaluate the performance of our algorithm using a simulation and show that it performs better compared with a previous algorithm.

Dynamic modeling and fuzzy augmented PI control of a high-rise building hot water heating system

Energy consumption of hot water heating (HWH) systems in high-rise buildings is a topic of considerable economic interest. In this study a dynamic model of a HWH system was developed and an intelligent fuzzy logic operating strategy was designed to improve energy efficiency of the system. Dynamic responses of temperature and water mass flow rate in the system were studied. Two types of boiler temperature set-point strategies, one based on average outdoor air temperature method and the other using a fuzzy augmented system, were explored and their performance was compared. From the simulation results it is shown that the strategy based on the fuzzy inference system saved boiler fuel consumption by about 10%.

Problem of Determination of Optimal Supports Position for Jumbo Flat Glass with Free Edges

Recent trends in architecture are characterized with wide applications of laminated glass plates in facing systems of high-rise buildings, where the plates are oriented in both vertical and horizontal planes. This paper deals with mathematical description of optimization problem for location of finite number of rigid supports horizontally placed on jumbo flat glass plate with free edges. Associated state problem corresponding to Kirchhoff’s hypothesis of plate theory is solved. Further the optimization problem for finding location of the finite number of rigid supports, with respect to the condition for minimal deflection of the plate in the sense of 1 C -norm, is solved. Theoretical results are used in numerical simulation by the finite element method (FEM). It allows us to reduce the computation time for solution of real projects. Further application of such results is for example in the area of automatic handling in the flat glass production in the case of engineering design for location of vacuum gripping heads components of handling devices.

An analytical framework for seismic fragility analysis of RC high-rise buildings

An analytical framework and sample application are presented for the seismic fragility assessment of reinforced-concrete high-rise buildings. Since no probabilistic fragility relationships exist for this class of structure, the work fills an important void in regional earthquake impact assessment. The key element of the presented framework is the methodology for the development of a simple lumped-parameter model representative of the complex high-rise building system. This model was created in the ZEUS–NL environment to enable computationally efficient dynamic response history analyses of high-rise structures that were previously not possible and that can accurately account for the complex behaviour and interactions predicted by more detailed analytical models. The parameters for this model were selected using genetic algorithms. The development of a simple lumped-parameter model is presented for an existing high-rise structure with dual core walls and a reinforced concrete frame. The accuracy of the individual components of this model is compared with the predictions of more detailed analytical models and sample fragility curves are presented. The proposed framework is generally applicable for developing fragility relationships for high-rise building structures with frames and cores or walls.

Elevator planning with stochastic multicriteria acceptability analysis

Modern elevator systems in high-rise buildings consist of groups of elevators with centralized control. The goal in elevator planning is to configure a suitable elevator group to be built. The elevator group must satisfy specific minimum requirements for a number of standard performance criteria. In addition, it is desirable to optimize the configuration in terms of other criteria related to the performance, economy and service level of the elevator group. Different stakeholders involved in the planning phase emphasize different criteria. Most of the criteria measurements are by nature uncertain. Some criteria can be estimated by using analytical models, while others, especially those related to the service level in different traffic patterns, require simulations. In this paper we formulate the elevator planning problem as a stochastic discrete multicriteria decision-making problem. We compare 10 feasible elevator group configurations for a 20-floor building. We evaluate the criteria related to the service level in different traffic situations using the KONE Building Traffic Simulator, and use analytical models and expert judgments for other criteria. The resulting decision problem contains mixed type criteria. Some criteria are represented by the multivariate Gaussian distribution, others by deterministic values and ordinal (ranking) information. To identify configurations that can best satisfy the goals of the stakeholders, we analyze the problem using the stochastic multicriteria acceptability analysis (SMAA) method.

Energy policy for integrating the building environmental performance model of an air conditioned building in a subtropical climate

For an air conditioned building, the major electricity consumption is by the heating, and air conditioning (HVAC) system. As energy saving strategies may be in conflict with the criteria of indoor air quality and thermal comfort, a concept of the building environmental performance model (BEPM) has been developed to optimize energy consumption in HVAC systems without any deterioration of the indoor air quality and thermal comfort. The BEPM is divided into two main modules: the adaptive comfort temperature (ACT) module and the new demand control ventilation (nDCV) module. This study aims to enhance and prompt the conventional operation of the air side systems by incorporating temperature reset with the adaptive comfort temperature control and the new demand control ventilation system in high rise buildings in Hong Kong. A new example weather year (1991) was established as a reference to compute the energy use of HVAC systems in buildings in order to obtain more representative data for predicting annual energy consumption. A survey of 165 Hong Kong office buildings was conducted and it provided valuable information on the existing HVAC design values in different grades of private commercial buildings in Hong Kong. It was found that the actual measured values of indoor temperature were lower than the design ones. Furthermore, with the new example weather year and the integration of the BEPM into Grade A private office buildings in Hong Kong, the total energy saving of the air conditioning systems was calculated (i.e. a saving of HK$122 million in electrical consumption per year) while the thermal comfort for the occupants was also maintained.

Nonlinear seismic response analysis of reinforced concrete tube in tube structure

Super-highly reinforced concrete tube in tube structure is a developing structure system of high-rise building. The more reasonable derivation process of the multi-vertical-line-element model stiffness matrix is given. On the premise of pointing out the problems of present multi-spring element model, combined with present multivertical-line-element model for analyzing on shear wall, the model is expanded to spatial one, and the stiffness matrix of which is derived. Combined with hysteretic axial model and hysteretic shear model, it is suitable for columns, wall limbs and beams with all kinds of section form. Some examples are calculated and compared with test results, which shows that the models have relatively good accuracy. On the base of the experimental phenomenon and failure mechanism for tube in tube structure specimen, nonlinear seismic responses analysis program on the basis of the advantaged element model for tube in tube structure is developed. Calculation results are in good agreement with those of the pseudo-dynamic tests and the failure mechanism can be well reflected.

Improved productivity using a modified table formwork system for high-rise building in Korea

Recently, construction of high-rise buildings in Korea has increased. However, the traditional formwork has disadvantages, such as low productivity, labour intensiveness, and long cycle times. Formwork is one of the largest cost components of a concrete building's structure, and is a factor with significant impact on construction duration. This paper proposes a modified table formwork system (MTFS) that can improve construction productivity, reduce labour requirements, accelerate construction schedules, and significantly reduce construction costs. A case study was performed to verify the validity of the MTFS by comparing schedules and costs of the MTFS with those of the traditional formwork system (TFS).

Development and Realization of Base Isolation System for High-Rise Buildings

High-rise buildings with a base isolation system have been realized by investigating the aspect of practical applicability through the identification and addressing of the difficulties involved in actual design applications. Among the base-isolated buildings we have designed so far, the Sendai MT Building is the first base-isolated building with a height exceeding 60 m in Japan, and the Thousand Tower was the tallest base-isolated residential Tower in Japan when completed. These examples show that the appropriate utilization of the base isolation system with high-strength materials and a long-span structure system makes it possible to endow high-rise buildings not only with strong seismic performance but also architectural design flexibility. This paper provides empirical evidence that the base isolation system can properly work for high-rise buildings. According to the seismic data obtained from the seismographs in the Sendai MT Building when the Off-Miyagi earthquake struck on May 26, 2003, the base isolation system of this high-rise building performed as effectively as designed.

Cyclic Behavior of Traditional and Innovative Composite Shear Walls

Shear wall systems are one of the most commonly used lateral-load resisting systems in high-rise buildings. The composite shear wall system studied herein consists of a steel plate shear wall with a reinforced concrete wall attached to one side of it using bolts. In this paper, experimental studies of three-story composite shear wall specimens are presented and test results are discussed. Two half-scale specimens were tested and both showed highly ductile behavior and stable cyclic postyielding performance. The specimens were able to tolerate 33 cycles of shear displacements and reach maximum interstory drift of more than 0.05. Here the interstory drift is defined as lateral movement of the floor over the story height. The bolts connecting the reinforced concrete walls to steel plate shear walls were able to ensure the composite action by bracing the steel plate shear wall to the reinforced concrete shear wall and preventing the overall buckling of steel plates. During late cycles and after shear yielding of the steel plate, inelastic local buckling of the steel plate shear wall occurred in the areas between the bolts. The experimental results and their implication in seismic design are summarized and discussed.

Mitigation Of Wind Effects On The Performance Of Pressurization Systems In High-rise Buildings

Stairwell pressurization systems should ensure a sufficiently high velocity at open doors between the stairwell and the fire floor without exerting large forces on closed doors in the stairwell. It appears, however, that strong winds may make it difficult, and many times impossible, to fulfill simultaneously these two requirements in tall buildings. A simple model is used for evaluating the possible use of different design parameters, such as the shape and size of the stairwell, the flow resistance of the exit path, the orientation of the exit door, relative to the direction of prevailing strong winds, additional lobbies, pressurization of the elevator shaft, and the type and location of the injection system, for mitigating the effect of winds on the performance of pressurization systems. Several examples are presented and compared. One novel finding is that the use of a helical stairwell configuration, which has a relatively low flow resistance, may drastically reduce adverse wind effects. Results of a 1:10 scale model study of flow in a helical stairwell are presented, which show that its resistance to flow resistance is approximately one quarter of that of convectional type stairwells.

A Study on the Reliability of Fire Water Supply System in High-rise Buildings

This paper puts forward the significance of study for the reliability of fire water supply system in high-rise buildings, as an exploration for the reliability of fire water supply system to attract the attention from experts on this issue. It briefly introduces the reliability model and calculation of the system, and analyses functional application process and probability features of the system. It raises the principles of reliability design and the method of improving reliability to benefit the optimization of fire water supply system design. Moreover, the development of reliability study has been looked ahead in the paper.

SK Headquarters Building, Seoul

A tubular system for high-rise buildings might be inappropriate for steel structures in contrast to reinforced concrete ones. However, such a system had to be selected for the SK Headquarters Building because of fast track construction together with increased building storeys. Despite well-known disadvantages due to a lot of steel moment connections in a tubular system, the cooperation of architects and structural designers explored the advantages, such as reduced floor height and an effective metal frame of curtain wall as well as simpler core and office area planning.