Multi-storey Buildings Research Articles

Indoor altitude estimation assisted by inertial compensation and online floor modeling

Abstract Indoor pedestrian altitude information plays a key role in such applications as emergency relief and military reconnaissance. However, height errors of inertial positioning grow without boundary because of the altitude channel divergence of the Strap-down Inertial Navigation System (SINS). This article proposes a new vertical location method based on the foot-mounted Inertial Measurement Unit (IMU) and online floor modeling. First, the number of stairs at each step is calculated after the height of each step is corrected by the error compensation model. Second, the prior height is estimated by utilizing the number of stairs and the stair height. Then, the key point library related to the floor is built online. Finally, the error correction of the vertical displacement is carried out by matching the prior height with the key point library. The gait classification shows that the accuracy based on the error compensation model can reach up to 99%. Moreover, the maximum attitude error is less than 1 m and the accumulated vertical positioning errors are eliminated completely when a pedestrian walks up and down inside a multi-story building, and all these have verified accuracy and robustness of vertical indoor positioning.

An experimental case study of escooter fire in a four-story building

Driven by the necessity to understand the fire and smoke dispersion characteristics of electric bicycle (escooter) fires and their effects on residents’ safety in rural houses, this study was conducted to perform full-scale fire experiments in a village house in Hainan, People’s Republic of China. The tested building is a typical multi-story building representative of rural houses in southern China. It is found that an escooter fire grows rapidly once its lithium-ion battery is overcharged to ignite. Inside the stairwell where the escooters are parked, a significant increase in temperature over 60°C across all floors is observed and the maximum temperature reaches up to 800°C on the first floor. Furthermore, the propagation of smoke is fast, reaching the upper floors within 5 minutes and filling the entire building within 7 minutes. Due to stack effect, carbon monoxide concentration is the highest on the fourth floor, notably higher than the other floors. Closing the doors of rooms where occupants are typically present is found to effectively block heat and smoke transfer. Thus, in case an escooter’s lithium-ion battery undergoes explosion combustion, it is better that residents stay in rooms by closing or even sealing the doors, waiting for help during most of the fire period. However, in case the lithium-ion battery has not been burning, there still are chances for evacuation or putting out the flame.

ОБЕСПЕЧЕНИЕ ПОЖАРНОЙ БЕЗОПАСНОСТИ МНОГОЭТАЖНЫХ ЗДАНИЙ ИЗ ДЕРЕВЯННЫХ КОНСТРУКЦИЙ

Проведен обзор современного деревянного домостроения в России и за рубежом. Проанализированы результаты испытаний строительных материалов из древесины на пожарную опасность, а также деревянных строительных конструкций различных типов на огнестойкость и пожарную опасность как без огнезащиты, так и с огнезащитой различных видов. Разработаны предложения в нормативные документы. Намечены направления дополнительных исследований пожарной опасности зданий из деревянных конструкций. The paper considers the issues of ensuring fire safety of multi-storey buildings made of timber frame construction. At present, wooden houses in Russia are built mainly in the individual housing sector and account for 22% of the total construction volume, while industrial wooden houses account for no more than 3% of the wooden houses built annually. Abroad, wood is also widely used in the construction of buildings of various functional purposes: hotels, sports facilities, public and administrative buildings, low-rise and multi-storey buildings. The achievements of science, technology and engineering in the field of timber construction make it possible to design and build buildings of any type and purpose. Modern technology makes it possible to build high-rise timber houses. For example, high-strength composite materials based on wood are used for the construction of multi-storey buildings, in particular LVL beams and CLT panels. Numerous tests carried out at VNIIPO on load-bearing elements made of solid wood (frames, beams) and load-bearing structures made of CLT panels (walls, ceilings) have shown that they provide a significant limit of fire resistance in terms of load-bearing capacity. It is well known that wood is a highly flammable material (G4). This circumstance significantly complicates the use of various building structures in construction from the point of view of ensuring fire safety requirements, including in multi-storey buildings. A set of necessary engineering, technical and organisational measures to ensure fire safety has been developed for buildings with wooden structures up to 4 storeys. Based on the results of these tests, there have been developed proposals to include fire technical parameters in the regulatory requirements for buildings of classes I–III of fire resistance and structural fire hazard class C3. Further research is necessary to develop proposals for inclusion in the regulatory documents for fire safety of multi-storey residential and public buildings made of timber structures up to 28 metres in height.

Unsymmetricity effects on seismic performance of multi-story buildings

The unsymmetrical configurations in buildings lead to non-uniform distributions in their strength, mass, and stiffness, and they are consequently prone to damage during seismic hazards. In this study, the seismic performance of multi-story buildings with 5, 8, 10, and 12 stories of square, ‘L’, ‘T’, and ‘U’-shaped buildings have been investigated. The research deals with the variation of the natural time periods and how it affects the seismic performance of unsymmetrical multi-story buildings. The coupled and uncoupled equations of motion, based on the symmetricity of the buildings about both axes, were solved to obtain natural time periods that influence the spectral acceleration of the ground accelerations. Six important ground accelerations were considered. Nonlinear static analysis, such as pushover analysis, was also carried out on all the buildings. Comparisons were made on the seismic behavior of both the symmetrical and unsymmetrical structures. The results revealed that the spectral acceleration influences dynamic responses, such as base shear, base moment, base torsion, roof displacement, roof rotation, and story drifts of the buildings. Moreover, it was found that even though the ‘L’-shaped buildings are unsymmetrical about both axes, they are less vulnerable than the ‘T’ and ‘U’-shaped buildings, which are unsymmetrical about one axis.

Study of effective location of shear wall in multi-storeyed buildings for optimum seismic response

In the seismic resistant design of high-rise structures, shear walls which are constructed along the height of the building are capable of transferring lateral forces from peripheral walls, floors, and roofs to the ground foundation. The main objective of the present study is to determine the effective location for shear walls in a multi-storey building for an optimum seismic response. The “Dynamic Response Spectrum method” of analysis of the building is done using ETABS. The effectiveness of shear walls has been studied by considering four different models. Model-I is a bare frame structural system without a shear wall and the other three models are dual-type structural systems with shear walls at different locations. In this study, a 16x16m plan with G+15 stories RC building with a total height of about 48m is analysed in zone V by providing shear walls of 250mm thick at different locations in the building. From the analysis results it is observed that the model with a shear wall placed at the centre of the building is more effective in resisting seismic forces when compared to other models.

Ajna: A Wearable Shared Perception System for Extreme Sensemaking

This paper introduces the design and prototype of Ajna, a wearable shared perception system for supporting extreme sensemaking in emergency scenarios. Ajna addresses technical challenges in Augmented Reality (AR) devices, specifically the limitations of depth sensors and cameras. These limitations confine object detection to close proximity and hinder perception beyond immediate surroundings, through obstructions, or across different structural levels, impacting collaborative use. It harnesses the Inertial Measurement Unit (IMU) in AR devices to measure users’ relative distances from a set physical point, enabling object detection sharing among multiple users across obstacles like walls and over distances. We tested Ajna's effectiveness in a controlled study with 15 participants simulating emergency situations in a multi-story building. We found that Ajna improved object detection, location awareness, and situational awareness, and reduced search times by 15%. Ajna's performance in simulated environments highlights the potential of artificial intelligence (AI) to enhance sensemaking in critical situations, offering insights for law enforcement, search and rescue, and infrastructure management.

Horizontal shaking table tests on a four-story prototype structure using multi-dimensional earthquake isolation and mitigation devices

Three-dimensional isolation system (3DIS) has been increasingly applied to civil structures with small height-width ratios, but is rarely employed in the multistory and high-rise buildings due to the lack of efficient control strategy for the rocking effect. In this paper, a simplified analysis model of 3DIS was established firstly to bring insights into the coupled motion mode caused by the rocking effect, and the influence of damping ratio and height-width ratio on the modal frequency was revealed. Then, aimed at weakening rocking motion and improving the seismic isolation efficiency, a novel multi-dimensional earthquake isolation and mitigation device (MEIMD) was proposed, and both the design composition and design principle were given in detail. To validate the effectiveness of MEIMDs, a full-scale four-story frame with a height of 13.05 m and a weight of 70 tons was produced for horizontal shaking table tests. The experimental results indicated that after adopting MEIMDs, the first-order modal frequency was 1.7 Hz, with 68% decrease compared with that of the prototype structure, and the first-order modal damping ratio was above 0.23, about eight times that of the prototype structure. Moreover, the horizontal peak acceleration was significantly decreased for each floor with a maximum reduction of 49%, while the maximum horizontal displacement and rocking response were obviously lower than the limit value specified by building codes. Therefore, the MEIMDs can not only efficiently isolate the earthquake energy, but also ensure the sufficient dynamic stability of the system. This study sheds light on the real coupled horizontal-rocking response of the base isolation system with MEIMDs, and can promote the development and application of 3DIS in multistory and high-rise buildings.

Passing-through I-plates-to-SHS moment resisting joints subjected to symmetric bending moments

When using hollow structural section (HSS) members in multi-storey buildings, beam-to-column moment resisting connections’ design raises critical questions to tackle. With conventional welded and bolted joints’ response being generally very flexible, the design resistance becomes governed by a deformation criterion rather than a strength criterion. This underscores the necessity for smart reinforcement techniques. A widespread solution is the diaphragm approach, in which the stiffeners usually protrude over the tubular column. The solution of plates passing through the HSS column is another stiffening option which was studied recently for CHS, yet, SHS columns have not been subject to comparable scrutiny. The objective of this paper is to study experimentally, numerically, and analytically the mechanical behaviour of I-beam-to-SHS column moment resisting joints using passing through I-plates under symmetric bending moments. The testing of two full-scale specimens corroborates previous findings with CHS columns in the elastic regime. However, significant deviations were observed in the post-peak response, revealing new insights into the behaviour of SHS columns. Failure was due to progressive buckling of passing through plates and yielding of tube-wall in transverse compression. A finite element model using solid and contact elements is developed and validated against experimental data. This model underscores how loads are redistributed between the tube wall and passing plates. A simplified version of the FE model is used to perform a thorough parametric numerical analysis on 101 configurations expanding upon the experimental test database by varying geometrical parameters such as passing plate thickness, tube, and beam dimensions. Finally, an analytical model integrating the different components of the joint is proposed to evaluate the initial rotational stiffness and the bending resistance.

Educating non-specialized audiences about seismic design principles using videos and physical models

The prevalence of self-construction practices in Türkiye has resulted in a building stock whose earthquake resilience is highly uncertain. To mitigate the potentially devastating impact of anticipated large earthquakes, one viable approach is to increase earthquake awareness among builders themselves. However, these builders lack formal engineering training and are ordinary citizens. Therefore, the challenge lies in devising visual teaching methods, such as short videos, to explain complex seismic phenomena in a comprehensible manner. This paper introduces the use of educational media tailored for non-specialized audiences, encompassing regular citizens and students without engineering backgrounds. These videos are based on experiments conducted with physical models on a homemade shake table. They focus on key factors influencing the seismic response of multi-storey buildings and highlight common design and construction errors that lead to building damage. To assess the effectiveness of this approach, we conducted a workshop with junior architecture students, followed by post-workshop qualitative assessments through knowledge surveys and interviews. The findings indicate that while single-topic videos were effective learning tools for students without prior knowledge of seismic building design, students found models particularly useful for explaining specific concepts such as torsional behavior, the role of diaphragms, and the performance of non-structural components. However, despite positive feedback on the effectiveness of model testing, students generally did not perceive significant knowledge acquisition in model construction. Ultimately, the accessibility of freely available videos, coupled with their enhanced educational value, makes them effective tools for raising seismic awareness in communities vulnerable to future earthquakes.

A Method for Determining the Fundamental Site Period and the Average Shear Wave Velocity

The soil–structure interaction plays a crucial role in determining the displacement and internal forces of multi-story buildings subjected to strong ground motion. One of the critical dynamic characteristics influencing soil–structure interaction is the fundamental site period and the average shear wave velocity associated with it. This study introduces an original equation to determine these parameters. In addition, for the first time in the literature, the version of the Rayleigh method used for finding the fundamental periods of buildings is used to find the fundamental site period. The soil is modeled as an equivalent shear beam to obtain the proposed equation. The peak displacement is obtained by acting the soil mass as an external load on the equivalent shear beam. For single-layer soil, the fundamental site period is proportional to the square root of the peak displacement of the equivalent shear beam. The least squares method generalizes the proposed relation for single-layer soils to multi-layer soil profiles. Modified Finite element Transfer matrix method is used for calibration in the least squares method. The equations used in the literature and earthquake codes for determining the fundamental site period and average shear velocity are tested on various examples, and it is shown that the method proposed in this study, along with the Rayleigh method, gives better results than these equations. The performances of these two methods and the five commonly used equations are tested and compared on different soil profiles. Transfer functions, Finite Element Method (SAP200) and Modified Finite Element Transfer Matrix Method are used for verification. For all soil profiles, the results obtained from the transfer function, Finite Element Method (SAP200) and Modified Finite Element Transfer Matrix Method are found to be in agreement. The true percent relative error found in the results obtained with the proposed method is 4.47%.

Lateral-torsional buckling investigation of multi-tiers eccentrically braced frames with shear link beam

Multi-tiered braced frames (MTBF) are a type of braced frames with two or more tiers of bracing or bracing panels between horizontal diaphragm levels or locations of out-of-plane support, along with a beam at every tier level. They are commonly used in tall single-story building structures when it is not practical to use single bracing members spanning from roof to foundation levels. Additionally, they find application in multistory buildings with tall story heights. In this paper, lateral-torsional buckling of beams in a new type of MTBF called multi-tiered eccentrically braced frames (MT-EBF) is evaluated. This structural system is not mentioned in any of the current code and seismic criteria have not been provided. The main different of this system with eccentrically brace frame is the lack of laterally supported in the intermediate beam. Also, in industrial buildings that need architectural openings, this system is more useful than concentrically braced frame. For this purpose, the seismic behavior of four different MT-EBF with one and two tiers, along with two different configurations for the connection of braces to the beams, is studied. In the first configuration, the braces are connected to the beam using a gusset plate, and in the second configuration, the braces are directly connected to the beam using full penetration groove weld. The results of the numerical study indicate that in the first configuration, lateral-torsional buckling occurs in the intermediate beams, and the connection of the gusset plate to the beams lacks the necessary stiffness to prevent lateral-torsional buckling. However, in the second configuration, lateral-torsional buckling of the intermediate beams is prevented, and the connection of the braces to the beams has the adequate stiffness to prevent lateral-torsional buckling.

Impact of balcony geometry on the performance of rubberized concrete structures against progressive collapse

PurposeEvaluate the performance of progressive collapse of full-scale three-dimensional structure (3D) beam-slab substructures with and without the presence of reinforced concrete (RC) balconies using two concrete mixes [normal concrete (NC) and rubberized concrete (RuC)].Design/methodology/approachThis study examines two concrete mixes to evaluate the progressive collapse performance of full-scale 3D beam-slab substructures with and without the presence of RC balconies using the finite element (FE) method.FindingsThe results showed that the vertical loads that affect the structures of the specimens after including the balconies in the modeling increased by an average of 29.3% compared with those of the specimens without balconies. The specimens with balconies exhibited higher resistance to progressive collapse in comparison with the specimens without balconies. Moreover, the RuC specimens performed very efficiently during the catenary stage, which significantly enhanced robustness to substantial deformation to delay or mitigate the progressive collapse risk.Originality/valueAll the experimental and numerical studies of the RC beam-slab substructures under progressive collapse scenarios are limited and do not consider the balcony’s presence in the building. Although balconies represent a common feature of multistory residential buildings, their presence in the building has more likely caused the failure of this building compared with a building without balconies. However, balconies are an external extension of RC slabs, which can provide extra resistance through tensile membrane action (TMA) or compressive membrane action (CMA). All those gaps have not been investigated yet.

Development of a Computer-Aided Algorithm to Determine the Floor Wise Column Size for Multi-storey Base-Isolated RC Frame Buildings

Development of a Computer-Aided Algorithm to Determine the Floor Wise Column Size for Multi-storey Base-Isolated RC Frame Buildings

Performance Evaluation of Foamed Concrete with Lightweight Aggregate: Strength, Shrinkage, and Thermal Conductivity.

Lightweight concrete offers numerous advantages for modular construction, including easier construction planning and logistics, and the ability to offset additional dead loads induced by double-wall and double-slab features. In a previous study, authors proposed incorporating lightweight aggregate into foamed concrete instead of adding extra foam to achieve lower density, resulting in lightweight concrete with an excellent strength-to-density ratio. This paper further investigated the performance aspects of foamed concrete with lightweight aggregate beyond mechanical strength. To evaluate the effect of aggregate type and foam content, three mix compositions were designed for the lightweight concrete. Specimens were prepared for experimental tests on thermal conductivity and drying shrinkage of lightweight concrete. Results showed that while both the increase in foam volume and the incorporation of lightweight aggregate led to higher drying shrinkage, they also contributed to improved insulating properties and reduced potential of cracking. Using typical multi-storey modular residential buildings in Hong Kong and three other Chinese cities as case studies, simulations were performed to assess potential savings in annual cooling and heating loads by employing the proposed lightweight concrete. These findings demonstrate the practical benefits of using foamed concrete with lightweight aggregate in modular construction and provide valuable insights for further optimization and implementation.

A Comparative Study on Seismic Analysis of Multistory Buildings of LGSS and Other Conventional Structure

The construction industry is increasingly turning to innovative materials and techniques to address modern demands for efficiency, sustainability, and resilience. Among these innovations, Light Gauge Steel Structures (LGSS) have emerged as a noteworthy alternative to traditional construction methods known for their versatility, efficiency, and reduced environmental impact, LGSS provides several benefits over conventional materials like Reinforced Cement Concrete (RCC) and Hot Rolled Steel Structures . These advantages include rapid assembly, enhanced seismic performance, and a lower overall environmental footprint.

The Influence of Variations in Shape and Placement Sliding Walls on The Behavior of Multi-Story Building Structures to Withstand Earthquake Loads (Case Study: Building Pasar Raya Inpres Block)

System the structure of Building a Pasar Raya Inpres Padang Block IV, namely system double that uses wall shift as retainer lateral load and SRPMK as retainer style gravity, but cold sliding on the building the only there is on the 1st floor only if wall shifts No continuously until building roof floor so can influence behavior structure building the like mark style shift basis, displacement, deviation between the floor and p-delta influence. The study this aims to compare mark style shift basis, displacement, and deviation between which floor and p-delta later will compared against 4 variation models shape and placement wall shift. The method used that is method comparative with analysis uses response spectrum using ETABS software. Results of the study show model 2 structure has a mark base shear namely 3658,658 kN. Model 2 has a mark displacement the smallest in the x direction is 3,766 mm and Model 4 has a mark displacement the smallest in the y direction is 2,347 mm. Model 2 has a mark deviation atar floor smallest namely 8,019 mm for the X direction and 4,015 for the Y direction. All models are confirmed safe at the moment checking the P-Delta effect, with model 2 having the mark lowest for the X direction and Y direction.

The Buildings’ Reliability Calculating Method Using a Simple Seismic Impact Model

Non-canonical spectral representation of seismic activity is employed to assess the reliability of nonlinearly modeled buildings. Seismic impact is modeled using a random process, represented by simple functions with random parameters. We consider random processes with correlation functions expressed as a sum of cosine-exponential terms. Reliability, defined as the probability of failure-free operation, is determined using statistical testing methods. The reliability calculation algorithm is implemented in MATLAB. As an illustrative example, we calculate the reliability of a section of a one-story industrial building frame modeled by a nonlinear system. Failure is defined as exceeding experimentally determined permissible displacement limits. Our calculations involve up to 2000 realizations of the random process. We analyze histograms, empirical distribution functions, and reliability values of maximum fragment movements. We find that using 100 realizations of the random process yields satisfactory accuracy in determining reliability. This reliability calculation method is recommended for rapid reliability estimates across various structure types, including those employing seismic isolation systems. We also observe a correlation between displacement magnitudes calculated under accelerograms and a random process represented in a non-canonical form. Thus, we recommend this method for reliability assessments in multi-story buildings. Doi: 10.28991/CEJ-2024-010-08-019 Full Text: PDF

Innovative multi-setup modal analysis using random decrement technique: a novel approach for enhanced structural characterization

PurposeThis paper introduces a novel multi-setup merging method and assesses its performance using simulated response data from a Finite Element (FE) model of a five-storey frame and experimental data from a cantilever beam tested in a laboratory setting.Design/methodology/approachIn the research conducted at the Central Building Research Institute (CBRI) in Roorkee, India, a cantilever beam was examined in a laboratory setting. The study successfully extracted the modal properties of the multi-storey building using the merging technique. Identified frequencies and mode shapes provide valuable insights into the building's dynamic behavior, which is essential for structural analysis and assessment. The sensor layout and data merging approach allowed for the capture of relevant vibration modes despite the limited number of sensors, demonstrating the effectiveness of the methodology.FindingsThe results show that reducing the number of sensors can impact the accuracy of the mode shapes. It is recommended to use a minimum of 8 sensor locations (every two floors) for the building under study to obtain reliable benchmark results for further evaluation, periodic monitoring, and damage identification.Originality/valueThe results demonstrate that the developed algorithm can improve the system identification process and streamline data handling. Furthermore, the proposed method is successfully applied to analyze the modal properties of a multi-storey building.

FEATURES OF ARCHITECTURAL FORM FORMATION OF ENERGY-EFFICIENT MULTISTORY BUILDINGS

Problem statement. The active use of renewable energy sources and the introduction of energy-efficient systems in all spheres of life today is the most important component of future development, which can change the life and comfort of every person. And it is very important to determine the place of architecture in this process. Analyzing the global experience of architectural activity in recent decades, especially in economically developed countries, it can be noted that engineering and technological systems of alternative energy are becoming an integral part of various types of buildings and complexes, both residential (low-rise, high-rise) and public (business, retail, cultural, multifunctional complexes, etc.). Alternative energy is becoming one of the factors influencing the layout and appearance of a building, the choice of materials and decorative finishing, and significantly influencing the formation of objects of new “innovative” architecture. Purpose of the article. To explore the features of the architectural form formation of energy-efficient multi-storey buildings as a result of the interdependence of architecture and energy-efficient technological systems using the example of modern architectural objects in the world. Conclusion. Engineering and technological systems of alternative energy for multi-storey buildings, based on renewable energy sources, provide such characteristics of buildings as: environmental friendliness, autonomy, self-sufficiency, profitability, energy efficiency and a high level of living comfort, architectural individuality and freedom of architectural form formation, unusual volumetric and compositional architectural solutions objects.

Component tests and numerical simulations of 3D steel frame structures for progressive collapse

This paper presents a comprehensive study on three-dimensional steel frame structures subjected to progressive collapse, drawing insights from a full-scale steel frame substructure test. The investigation encompasses connection component tests and numerical simulations, focusing on extended end plate and double-angle cleat connections employed in the substructure test. The mechanical properties of the connection components were tested, forming a basis for defining component properties in subsequent connection models. Finite element (FE) models of the test substructure were developed, utilizing hybrid elements for the steel frame part, which include beam, connector, and spring elements based on the component method. To simulate reinforced concrete slabs, a combination of refined solid elements and simplified shell elements was employed. The former accurately captures detailed failure modes, while the latter efficiently simulates the collapse behavior of large-scale steel frame structures. Validation of the established models against test results encompassed load-displacement responses, internal forces in structural members, and failure modes. The validated FE models were then utilized to analyze and discuss the contributions of various structural components in resisting progressive collapse. Specific focus was placed on the development of load-resisting mechanisms in the floor slab and the influence of beam-column connection types on structural behavior. The paper explores the role of bracing systems in a building in resisting progressive collapse. Additionally, it evaluates the effectiveness of the restraint systems used in the test, shedding light on their ability to accurately reflect real restraint effects from the surrounding structure. The findings presented herein contribute valuable insights to the understanding of progressive collapse behavior in steel frame structures, with implications for robustness design of multi-story steel buildings.