High-rise Buildings Research Articles

DNN-metamodeling and fragility estimate of high-rise buildings with outrigger systems subject to seismic loads

This paper proposed deep neural networks (DNNs) for the dynamic response of high-rise buildings with one-outrigger systems under two types of seismic hazards. Using an existing database, the hyperparameters for the architecture of the DNNs are determined finding a trade-off between accuracy and complexity. The performance of the proposed DNNs is compared with two metamodels in the literature, a probabilistic demand model and a kriging metamodel. Partial dependence plot and SHapley Additive exPlanations are used for the explanation of the marginal effect of each feature on the predicted outcome of a neural network from the perspective of global and local agnostic. Considering the uncertainty in the input features, the DNNs are then used to formulate fragility estimates for example high-rise buildings with three types of outrigger systems. The model-agnostic analysis suggests that the DNN targeting the inter-story drift and top acceleration shows extremely high sensitivity to variation in the seismic hazard features, earthquake magnitude, and rupture distance. The fragility curves objectively quantify the reliability of buildings with each of the three outrigger systems and show the effectiveness of damped outrigger systems in reducing fragilities.

Understanding and Addressing Non-Payment of Housing Maintenance Fees in Klang Valley: Challenges and Solutions

Housing maintenance fees are essential to maintaining the standard and operation of residential communities. However, non-payment issues present serious problems to the Joint Management Body (JMB) and residents due to various issues related to maintenance are delaying to be solved. Thus, this study objectively assesses the role and relationship of JMB with the respondents toward residents’ commitment and support in making payments for housing maintenance. A quantitative approach through a survey questionnaire was distributed among 31 respondents of high-rise buildings in Klang Valley for a pilot study. Four (4) independent variables were involved: the role of JMB, the relationship between residents and JMB, facilities provided, and safety and security towards the dependent variable of resident’s commitment and support. The findings show that most respondents agree that any problems related to the housing unit should be consulted with JMB and residents should get permission from JMB before proceeding with any necessary action. This study is expected to benefit JMB and residents in ensuring a sustainable harmonious housing environment in the high-rise buildings and thus contribute to the achievement of SDG 11: Sustainable Cities and Communities.

Experimental and theoretical study on axial compression behaviour of the modular combined column

Between the modular units of the modular steel building, there exists a combination of the adjacent modular columns. Due to the gaps between the modular columns and the lack of horizontal connections, the integrity of the modular steel structure is weak, which limits the use of modular steel structures in high-rise buildings. This paper proposes a kind of modular combined column realized the connection of modular single columns through the connectors and concrete, which can improve the integrity of the modular steel building. The assembly process of this new modular combined column is described. For axial compressive performance tests, four modular combined column specimens were designed, each with different height or different number of connecting plates. The axial compressive bearing capacity, ductility, stiffness, and other mechanical parameters of the specimens were analyzed according to the phenomena and load-displacement curves of the test. Then, the axial compression failure mode of the modular combined column specimens is compared and analyzed in conjunction with the finite element model. The results indicate that the axial compressive performance and ductility of the combined column suggested in this research are exceptional. The connector can enhance the overall mechanical qualities of the combined column by augmenting the restraining impact of concrete. Finally, the theoretical equation of the axial compression bearing capacity of the modular combined column is obtained by employing the superposition principle, and the equation's reliability is confirmed, along with the test results and the results of the numerical analysis.

Effectiveness of natural ventilation in controlling the smoke spread within a refuge floor of a high-rise building

Refuge floors in high-rise buildings ensure a haven for occupants to stay in an emergencyprimarily during a fire breakout. Provisions for natural ventilation of the refuge floor are mandatory in all fire codes as they help release smoke and heat build-up. However, the effectiveness of such provisions has been questioned in many studies. This research employs large eddy simulations based three-dimensional computational fluid dynamics modelling on a real-world high-rise building to investigate the efficacy of natural ventilation in a refuge floor during a fire. Consequently, the performance was assessed by evaluating the temporal and spatial distributions of temperature, visibility, smoke and carbon monoxide concentration. Emphasis was placed on determining the adequacy of window placement and openings. Analysis was started with a code-compliant window configuration. Subsequently the window size and the layout were iteratively modified using simulation results. Seasonal wind variations were also considered. Results showed that a well-engineered natural ventilation strategy can considerably improve the refuge floor habitability. Simulations also revealed limitations of natural ventilation under certain wind conditions, necessitating a backup mechanical system. This also underlined that combining fire analysis with cutting-edge modelling allows tailored natural ventilation for refuge floors, maximising safe occupancy during fires.

Experimental and numerical studies on seismic performance of a novel lead viscoelastic coupling beam

Replaceable coupling beams (RCBs) with different types of dampers have gained significant attention in coupled shear walls for enhancing seismic performances in high-rise buildings, showing superior advantages to conventional reinforced concrete coupling beams (RCCBs). Recently, the authors proposed the hybrid lead viscoelastic damper (HLVD), and its basic mechanical behaviors were experimentally studied. This paper used the HLVD as a replaceable fuse and installed it in the coupling beam to form a new RCB, i.e., lead viscoelastic coupling beam (LVCB). To examine the seismic performance of the LVCB, experimental and numerical studies were carried out in the present study. Quasi-static tests were conducted to comparatively investigate the seismic performances of the RCCB and LVCB. The experimental findings revealed that the RCCB experienced shear failure with severe pinching behaviors under cyclic loadings, while the LVCB exhibited a resilient behavior, showing favorable energy dissipation capacity with a ductile deformation capacity exceeding a rotation angle of 0.04 rad. The LVCB also demonstrated excellent recoverability in repeatability tests, proving its merit for maintaining post-earthquake functionality. Numerical simulations indicated that adjusting the lead rods of the LVCB could conveniently enhance the load-carrying capacity and energy dissipation capacity of the LVCB. The isolated floor slab was recommended as a low-damage control solution for the LVCB to facilitate post-earthquake replacement.

How to get high-rise residential design to respond road traffic noise

Rapid urbanization causes acute contradictions of road traffic noise on residents' health. Although many works have been done in this field, specific investigations of how to get a design of residential area to correspond road traffic noise is still limited, especially in a high population dense area. This paper, therefore, focused on high-rise residential blocks, researching relations between design variables and distribution of road traffic noise. In the study, a typical high population dense city, Shenzhen was employed as study case. Based on noise map simulation, design element, block layout, design of individual buildings was proved important in traffic noise impact. The results discovered that the noise reduction effect is relatively significant when the building setback is within 30 - 40 meters of setback curb. To minimize traffic noise impact, flexible layout of board point perimeter type might play an important role. Lowering building heights with increasing the number of building rows, two-story podiums around high-rise buildings, and the addition of balcony railing plate could result in significant noise reductions. Focusing on design elements, this work developed an overall evaluation to improve acoustic environment of high-rise residentials based on noise map simulation, and provided significant contributions in responding road traffic noise.

Noise reduction and visual disturbance performances of horizontal facade profiles for a multi-story high-rise apartment building

This paper simulates the noise reduction performance of horizontal profiles installed on the façade to reduce the external noise in high-rise residential buildings. The simulation used commercial software based on the ray tracing method and evaluated the performance by modeling a representative rectangular-shaped 30-story apartment building in South Korea. The simulation assumed a four-lane road traffic noise source parallel to the front of the apartment. The key simulation values were cited from configurations derived in previous studies. The sound absorption points were set at the center of each living room on every floor, and windows facing the road were considered for ventilation, being set to be partially open. Horizontal profiles for noise reduction were placed on the exterior of the building, starting from the 20th floor, with protrusion height and vertical spacing as variables. These profiles were combined with noise barriers to assess their impact. As a result, it was confirmed that the noise barrier only reduced the noise in the lower floors, while the horizontal profiles on the upper part of the building could also reduce noise in the upper floors. Additionally, the paper discusses the visual disturbance of the horizontal facade profiles visible from the living rooms.

Pulse component extraction and its application in simulation of pulse-like ground motions

A procedure for simulating new pulse-like ground motion based on natural pulse-like ground motion record is proposed. Firstly, an extraction method of pulse waveform based on Modified Ensemble Empirical Mode Decomposition is proposed, which reveals the relationship between half-wavelength width and pulse time-frequency information. Secondly, according to the response spectrum of the extracted non-pulse time-history, a triangular series is used to generate a stationary time-history, and then the extracted pulse component is added to the time-history, and the intensity envelope is adjusted to obtain the simulated pulse-like ground motion. Finally, the seismic response results of the Bouc-Wen-Baber-Noori model and the three-dimensional finite element model of the high-rise building are validated. It shows that the nonlinear effect of the simulated pulse-like ground motion by this method is close to that of the original natural pulse-like ground motion. The simulated pulse-like ground motion by this method can be used to analyze the inelastic response of various structures.

Energy performance and wind exposure of windward, lateral, and leeward high-rise photovoltaic facades

The growing demand for sustainable energy solutions leads to the integration of photovoltaic/thermal (PV/T) modules into building facades. This study evaluates and compares the energy potential, wind load, and environmental benefits of PV/T modules installed on different facades of high-rise buildings. Using advanced computational techniques, including Computational Fluid Dynamics (CFD), the wind interaction with PV/T modules on windward, lateral, and leeward facades is modeled and analyzed. Each computational process requires over two weeks to complete due to the complexity of the simulations. The results demonstrate that the leeward facade is more effective for electricity generation, while the windward and sideward facades perform better for thermal energy storage. Maximum energy outputs of 217 kW for thermal energy and 73 kW for electrical energy are recorded, depending on wind conditions. Additionally, energetic and exergetic efficiencies reach 55.2 % and 17.7 %, respectively. The study also finds that the leeward facade has the greatest impact on reducing CO2 emissions. These findings provide valuable insights into designing optimal PV/T facades for high-rise structures, expanding the range of structural designs and offering opportunities for implementing mitigation measures to enhance system durability and efficiency. The novelty of this research lies in the detailed comparative analysis of PV/T performance across multiple facades, offering a practical framework for future sustainable building designs.

Eccentric compression behavior of CFRP-confined reactive powder concrete-filled steel tube slender columns

Ultra high and large-span structural components are needed in urban modernization construction to meet the engineering requirements. Reactive powder concrete-filled steel tubes (RPCFSTs) provide a cost-effective and efficient solution for optimizing space utilization in super high-rise buildings and enhancing the crossing capacity of bridge, which accords with such development. However, these components have inherent drawbacks in terms of local buckling and corrosion resistance. The use of carbon fiber reinforced polymer (CFRP) confinement to suppress this innate deficiency has been proven to show great advantages in limited trial results. This article establishes a comprehensive test scheme to investigate the eccentric compression performance of CFRP-confined RPCFST columns. A total of 11 specimens were prepared and subjected to biased compression test by varying the component length (400, 800, 1200, and 1600 mm), number of CFRP layers (0–3), and load eccentricity (0, 10, 20, 30, and 40 mm). The results showed that the CFRP confinement could effectively enhance the bearing capacity and energy dissipation capability of RPCFST columns while delaying the local buckling of slender specimens with low slenderness ratios. The improvement of ultimate load due to CFRP confinement exceeded 42.5 %. However, in specimens with higher slenderness ratios and with increasing load eccentricity, the confinement effect of the steel tube on the core RPC tended to weaken. An N–M interaction model for slender CFRP-confined RPCFST columns was established, and this model was validated to be in good agreement with the experimental results. The conclusions drawn from this study might given a solid foundation for the future application of CFRP-confined RPCFST structures.

Tests on seismic and shear performance of RC shear walls under alternating axial tensile and compressive loads

Under strong earthquakes, reinforced concrete (RC) shear walls at the bottom of high-rise buildings may experience an internal force state of alternating tension-shear (-bending) and compression-shear (-bending). In order to clarify the seismic and shear performance of shear walls under alternating axial tensile and compressive loads (referred to as alternating axial loads), cyclic tests on five shear-controlled large-scale RC shear walls were conducted in this study. The tests were conducted with synchronized axial loads and horizontal displacements, and a quantitative analysis of the influence of the alternating axial loads was achieved by setting two control specimens. The crack development, failure modes, load-carrying capacity, deformation capacity, and energy dissipation of the specimens were measured and analyzed. The test results indicate that different axial load cases altered the crack pattern and failure mode. With an increase in the target axial tensile load, both tension- and compression-shear capacities of the specimens under alternating axial loads decreased, with the former experiencing a more significant reduction. In comparison to the tension-shear control specimen, it was observed that the alternating axial loads significantly reduced the displacement ductility of shear walls in the tension-shear state, resulting in substantially lower energy dissipation capacity. In addition, based on the tests in this study and the collected shear wall tests, the shear strength formulas in the current codes ACI 318-19 and JGJ 3–2010, as well as a shear model previously proposed by the authors, were evaluated. Based on the test results, a reduction factor was fitted to account for the effect of alternating axial loads on the compressive-shear capacity of RC walls.

IMPLEMENTATION OF THE MAIN COLUMN STRUCTURE USING THE FREESTANDING METHOD & STUDY OF LAP SPLICE CONNECTIONS ON THE GGM MAJALENGKA BUILDING PROJECT IN MAJALENGKA DISTRICT

The GGM Building is a circular sports building, has 2 floors with circular columns. Columns are the most important structural part for a building to stand. In accordance with SK SNI T-15-1991-03 what is meant is a building structural component column whose main task is to support axial, compressive and vertical loads. In this report study, the method used for the main column reinforcement work is Free Standing which can be interpreted as a structure that is strong and stands upright. The GGM Building is a high-rise building which of course has a structure that can stand perfectly upright at any height. The type of connection used in column cuttings is a contact lap splice which is a passing connection between two reinforcing bars that touch each other and are tied with concrete wire. SAP2000 software is used to analyze the values ​​of the forces acting on the main structural columns. Based on the results of analysis of the main structural columns using SAP 2000, the load distribution value was obtained, namely 22.81 KN/m with an axial force value of -229.220 KN for column type K1-1. 27.14 KN/m with an axial force value of -272.97 KN for column K1-2 and 31.86 KN/m with an axial force value of -320,150 KN for column K2. Then with manual calculations related to the self-load value of the main structural columns, namely 1,189.56 KN in column K1-1, 1,614.14 KN in column K1-2 and 1,981.11 KN in column K2. Keywords: column, lap splice, selfweight calculation, SAP 2000.

Impacts of building modifications on the turbulent flow and heat transfer in urban surface boundary layers

This study examines turbulent airflow and upward heat transport in real urban environments using a building-resolving large-eddy simulation model to understand the characteristics of turbulent airflow and upward heat transport when geometrical distributions of buildings are modified. The target areas were two real urban districts within Osaka City, Japan, having different morphological features. In the numerical experiments, the initial condition was set to a neutral condition in which temperature is uniformly distributed vertically, and buildings emitted heat at a constant rate. The results in the two districts indicated that the features of turbulence and heat transport distinctly differed with different building arrangement. Specifically, taller buildings significantly decelerated airflows and induced warming behind buildings. More high-rise buildings (which resulted in a larger building variability) in a district with a larger building density caused a large heat flux and warming at higher levels. The sensitivity experiments in which a density and height variability of buildings were modified showed that a building density at higher levels and a building height variability significantly influenced warming at upper levels. An increased building height variability weakened wind speed and disturbed horizontal heat advection, whereas a large building density caused numerous heat sources.

Effects of corner modification on the Strouhal number of high-rise buildings under skewed wind

In recent years, the effectiveness of building corner modification measures in reducing wind loads on high-rise buildings has attracted great attention. The Strouhal number is a critical parameter in calculating the wind-induced response and equivalent static wind load of high-rise buildings in the across-wind direction. However, few studies have investigated the effects of corner modification on the Strouhal number of high-rise buildings under skewed wind conditions. Therefore, twenty-five models with different corner modifications were examined using high-frequency force balance (HFFB) wind tunnel tests in this study. Based on the experimental results, the base force coefficients and Strouhal number of the high-rise buildings with three types of corner modifications are discussed and compared with those of the square model. It was found that these three types of corner modifications are all effective in reducing the maximum mean and standard deviation of base force in the across-wind direction, with the reduction effect increasing as the corner modification rate increases. Three states of vortex shedding under specific corner modifications are identified by utilizing wavelet transformation. Formulas to evaluate the Strouhal number considering the effect of corner modification types and wind direction angles are fitted. The fitted formulas coincide well with the experiment data.

Installation and Construction Techniques for Elevated Corridors in High-Rise Buildings

Installation and Construction Techniques for Elevated Corridors in High-Rise Buildings

Optimal Location for Tower Crane and Dynamic Trailer Parking in High-Rise Modular Building Construction Project

Optimization of tower crane positioning is essential in precast building construction to ensure that a crane is in the right position to offer the best value for placing precast elements. The first goal is the optimization of transportation distances made by tower cranes, which will address the issues of efficiency and cost. This is done in a way that provides for minimization of the distances that lie between the trailer parking where elements are parked, the tower crane, and the construction installation point. However, current research fails to address the dynamic movement efficiency of trailers, especially when handling multiple trailers and several models of tower cranes, making this scenario an optimization problem that is classified as NP-hard due to the likelihood of causing a combinatorial explosion. This work endeavors to present a new mathematical model that has been applied to the Genetic Algorithm (GA). The ideal demand-generated model is designed to solve the optimal model and position of tower cranes and the prospective positioning of trailers for parking. The feasibility and applicability of the method exploited in the study are also established through a project case study. When adopting the proposed planning model compared to the earlier planning scale, comparisons highlight a small yet significant saving of 6% in time and cost when lifting elements instead of providing them from the trailers by setting up a new on-site stockyard. In addition, a great deal of enhancement is also observed in the final solution aspects, where the developed GA has even reduced the operational time and cost by half a percent each. The results of this research offer best-practice approaches to the position analysis of tower cranes in precast building construction to bring scalability and cost optimization to bear on the construction business.

Optimization Analysis of Water Supply Mode for Fire Protection System of Super High Rise Building

Abstract In order to improve the applicability and reliability of the fire water supply capacity of super high-rise buildings, the fluid analysis software Flomaster was used for simulation. Through the existing pumps, valves, pipelines, pressure reducing valves and newly developed fire hydrants and other components, the fire water supply system of super high-rise buildings is modeled. The pressure distribution of the system pipe network under a given fire water supply mode is studied. The research shows that the simulation can analyze whether there is excessive pressure in the fire hydrant system under different flow conditions in the actual fire extinguishing process. This paper simulates the actual fire extinguishing process of the fire hydrant system through a specific engineering case. The pressure distribution and flow distribution under different flow conditions are obtained. The excessive pressure position of the fire pipe network system under the given fire pump model is obtained. It provides a method for guiding the selection of fire pump and the design of fire hydrant system pipe network. It has certain guiding significance for the subsequent optimization of the design scheme of the fire water supply network and the prediction of the performance of the R&D equipment.

Numerical reconstruction of atmospheric boundary layer seasonal turbulent wind field over a complex forest terrain

The wind characteristics of the atmospheric boundary layer (ABL) over complex forest terrains are inherently intricate, influenced by the interplay of rugged topography, seasonal climatic fluctuations, and periodic vegetation dynamics. These effects are especially evident in the near-ground wind field, which exhibits substantial seasonal variability. Conventional wind characterization methods, as outlined in current standards, often fail to accurately capture these seasonal variations, thereby complicating the reconstruction of the near-ground ABL turbulent wind field in complex forest terrains. Accordingly, we employ the narrow band synthetic random flow generation (NSRFG) technique within large eddy simulation (LES) to generate inflow turbulence representing the growing and baldness seasons in a complex forest terrain by adjusting parameter equations for seasonal adaptation and introducing new empirical equations for the turbulent spectrum. Subsequently, we verified the seasonal turbulent flow's statistical characteristics and flow structure to assess its feasibility and validity, ultimately establishing a ‘seasonal numerical wind field’ model. Finally, the seasonally modified LES-NSRFG method was applied to the numerical simulation of turbulent flow around the Commonwealth Advisory Aeronautical Research Council (CAARC) standard high-rise building model. A comprehensive comparison of wind effects was conducted for the CAARC model under varying incoming flow conditions. The results indicate that seasonal winds in a complex forest terrain significantly affect the building's vortex wake, increasing the irregularity and complexity of the structural wind pressure and base moment coefficients. Thus, the seasonal wind effect must be considered when designing wind-resistant engineering structures in forest regions moving forward.

Research on Wind Load Characteristics of High-Rise Building Sail-Shaped Tower Crown

Research on Wind Load Characteristics of High-Rise Building Sail-Shaped Tower Crown

Action of liquid tune mass dampers and base isolation in high rise buildings

In areas where earthquakes are common, high-rise structure seismic resistance is a major concern. The purpose of this research is to determine whether base isolation and liquid tuned mass dampers (LTMDs) can improve tall building seismic performance. A symmetrical G+8 story RCC structure in Zone V with medium grade soil is analyzed using ETABS software, Response Spectrum Analysis, and Equivalent Static Analysis to see how the structure behaves under different load combinations. For various structural configure rations, including basic models, models with water tanks, and models with base isolation, key factors such joint displacement, storey drift, base shear, and time period are evaluated. The results show that as compared to baseline models, models with damping and isolation systems exhibit much lower joint displacements, base shear forces, and story drift. In particular, base isolation models perform better in terms of reducing structural deformations and resisting lateral forces. Furthermore, shorter time periods and higher frequencies are routinely observed in base isolated models, suggesting enhanced dynamic response and energy dissipation capabilities. The paper also covers the flexibility and benefits of using LTMDs and base isolation to reduce seismic threats. Buildings can be successfully separated from ground motion by base isolation systems, and dynamic response can be countered by LTMDs using regulated liquid sloshing. The attraction of LTMDs in improving overall stability is increased by their adaptability in minimizing torsional and lateral vibrations. The study concludes by emphasizing how crucial it is to use cutting-edge structural retrofitting methods, including base isolation and LTMDs, to improve the seismic resistance of high-rise structures. In earthquake-prone areas, engineers and legislators may proactively protect tall buildings and guarantee a safer, more robust built environment by incorporating these technologies into construction standards and design procedures.