Multi-storey Structures Research Articles

DETERMINATION OF PARAMETERS OF AN EXPERIMENTAL MODEL OF A MULTI-STOREY STEEL FRAME

: The load-bearing capacity of the structure can be accurately determined on large models made from the same material (or a material with similar elastic properties) as the actual structure. The scale of the model can be 1/5-1/6. This depends not only on the actual dimensions of the structure but also on the material of the model. Experience shows that for metal and concrete models, it is reasonable to adopt a scale of 1/5-1/15. Previous studies show that analysis based on the calculation of an idealized multi-story steel frame structure without considering imperfections does not fully reflect the actual performance of the steel frame and may not always ensure the load-bearing capacity of the building and the operational requirements for permissible frame displacements. It is interesting to compare some approximate data on the cost of testing in kind with the cost of testing the model. Thus, full-scale tests of large-panel buildings erected on subsidence soils ac-count for 10 to 30% of the cost of the buildings themselves. The cost of such tests on models would be 2-3%, that is, 5-10 times cheaper. The provided data indicates the feasibility of using modeling in the design of structures. The research results can be used to refine and develop building codes and standards, enabling the calculation and design of multi-story buildings that account for the actual performance of the steel frame-work.

Investigation of Passive Controlled Post-Tensioning System on the Structural Behaviour of Precast Reinforced Concrete Beam–Column Connections

Precast structures are widely used in many parts of the world. This construction technique is more commonly preferred for low-rise industrial buildings than multi-story structures. The most commonly used column–beam connection in precast buildings is the dowel connection (DC). Past earthquakes in various parts of the world have shown that these connections do not provide sufficient resistance. The main deficiencies of such connections are that they are sheared or stripped due to the shear force demand from the in-plane effects of large earthquakes, and that they do not provide sufficient resistance to the overturning moments from the out-of-plane effects of the earthquakes. Correspondingly, many prefabricated buildings have collapsed during earthquakes, causing loss of life and property. This study proposes using post-tensioning tendon (PT) systems and systems created by adding steel springs (PTS) to eliminate the weaknesses in column–beam connections in precast structures. To this end, real-sized column and beam specimens used in precast buildings were produced, and experiments were conducted under the cyclic loads defined by the American Concrete Institute (ACI) Committee, Report 374, simulating earthquake effects for three different connection types (DC, PT, and PTS). It was observed that the proposed PTS connection type dissipated approximately one-third of the energy transferred to the joint through elastic deformation in the springs, compared to the DC and PT connection types. This indicates that the PTS specimens transferred significantly less energy to the column–beam connection region. Consequently, the PTS system exhibited much less damage in the column foundation and especially the column–beam connection areas than other test specimens. In conclusion, it can be stated that the use of the PTS connection type in prefabricated structures has high potential to reduce damages due to dynamic loads such as earthquakes.

Physically-based collapse failure criteria in progressive collapse analyses of random-parameter multi-story RC structures subjected to column removal scenarios

The definition and determination of dynamic collapse limit states for design and safety assessment of civil structures is still an open problem in the context of progressive collapse, in particular for structural reliability and robustness quantifications. Hence, this paper summarizes, compares, and evaluates three kinds of collapse failure criteria in literature for reinforced concrete (RC) multi-story frames subjected to column removal scenarios, including the displacement-based criterion, the resistance-based criterion, and the energy-based criterion. Totally, 48 deterministic cases and 480 stochastic cases for six different planar RC frames subjected to 48 different column removal scenarios are studied in the progressive collapse analyses to evaluate the effectiveness and performance of the three kinds of criteria. In the stochastic analyses, the depth of the concrete cover and the key material mechanical properties for both concrete and reinforcing steel are chosen as random inputs, where the uncertainties are observed to have great influence on the collapse limit states. The results demonstrate that the different structural designs and the uncertainties in structural parameters will lead to different collapse limit states, which are strongly linked with the specific failure modes or paths during the progressive collapse. The code-compliant seismic design can significantly improve the deformation capacity of the RC frames and allow sufficient development of load redistributions. In such cases, the empirical collapse failure criteria including both the deformation-based and the resistance-based criteria adopting an empirically prescribe deterministic threshold may fail to accurately determine the collapse limit states. None of them can be adaptive to different structures with different failure modes or paths, either too conservative or too much overestimating the performance. Conversely, the energy-based criterion adopting a physical approach rather than an empirical constant threshold is a physically-based and problem adaptive approach, which can be adaptive to different structures with different failure modes or paths according to the specific computational results. Hence, the energy-based criterion shows the best performance for determining the collapse limit states and is less affected by the different failure modes or paths.

Seismic Response Analysis of a Vibrating Stirred Steel Fiber Concrete Frame Structure Based on Probability Density Evolution

In this paper, an experimental study of steel fiber concrete using vibration mixing technology and the probability density evolution theory is applied to establish a nonlinear stochastic seismic response model for multistory concrete frame structures considering the randomness of structural parameters. The random evolution characteristics of the structural response are studied and analyzed, and a reliability analysis method for concrete frame structures based on PDEM theory is proposed. The equations are solved by the finite difference method in the TVD format, and the probability distribution of the deformation index of the concrete frame structure is obtained by summation, where the reliability is given according to the limit value of the index. The results confirm that the PDEM theory can accurately assess the functional reliability of the structure, and it is also found that the randomness of the structural parameters has a significant effect on its nonlinear dynamic response law, and that consideration of the randomness of the structural parameters at the early stage of the design can be of great help to the seismic resistance of the structure. This study not only provides a scientific basis for the optimization of the performance of steel fiber concrete but also provides a new perspective and tool for the analysis of probability density evolution in the field of structural earthquake engineering.

Performance of Dynamic Energy Absorbers in Multi-storey Structures with Incorporating Soil Structure Interaction

Performance of Dynamic Energy Absorbers in Multi-storey Structures with Incorporating Soil Structure Interaction

Numerical Analysis of Fire Resistance in Cross-Laminated Timber (CLT) Constructions Using CFD: Implications for Structural Integrity and Fire Protection

Fire represents a serious challenge to the safety and integrity of buildings, especially timber structures exposed to high temperatures and intense heat radiation. The combustibility of timber is one of the main reasons why regulations strictly limit timber as a building material, especially in multi-storey structures. This investigation seeks to assess the fire behaviour of cross-laminated timber (CLT) edifices and examine the ramifications for structural integrity and fire protection. Utilising computational fluid dynamics (CFD) simulations, critical variables including charring rate, heat emission, and smoke generation were analysed across two scenarios: one featuring exposed CLT and another incorporating protected CLT. The outcomes indicated that protective layers markedly diminish charring rates and heat emission, thereby augmenting fire resistance and constraining smoke dissemination. These revelations imply that CFD-based methodologies can proficiently inform fire protection design paradigms for CLT structures, presenting potential cost efficiencies by optimising material utilisation and minimising structural impairment.

Negative stiffness device for seismic protection of MDOF yielding fixed base structures: Experimental and analytical study

Shake table tests of single degree of freedom elastic/inelastic structures have confirmed that by adding a negative stiffness device (NSD), capable of exhibiting nonlinear elastic negative stiffness, in conjunction with a viscous damper, the acceleration, inter-story drifts, and base shear can be reduced significantly. However, little is known about how the presence of NSD/damper in the first story influences the response of higher stories of a multistory structure. In this paper, shake table test results are presented that demonstrate the advantages of NSD/damper in the first story of a multidegree of freedom, three-story, fixed-base structure (MDOF-3SFS). Results confirm that deployment of NSD/damper at the first story leads to significant reductions of acceleration as well as base shear and inter-story deformations in the MDOF-3SFS. Essentially, an NSD and a damper in the first floor prevents the transmission of the input energy from the ground motion to the second and third story of the multistory structure by deflecting and dissipating energy. If the first-story displacements become excessive, NSD stiffens and prevents collapse. The efficacy of the NSD/damper system is further demonstrated by comparing it with the performance of a structure with passive viscous dampers deployed in the first story. In addition to the reduction of base shear and maximum accelerations, the NSD/damper system also restricts large deformations to the first story only, leading to minimal damage to the whole structure. Finally, an NSD-based bracing system is introduced that can be deployed in new and existing structures.

LATERAL STIFFNESS EVALUATION OF RESIDENTIAL ISO CONTAINER MODULE: FULL-SCALED EXPERIMENTAL AND NUMERICAL STUDIES

International Organisation for Standardisation (ISO) containers, designed to protect contents against extreme conditions, are often repurposed as temporary shelters during disasters, conflict, or urbanization. However, modifying these containers for housing greatly affects their structural integrity. Several studies have numerically and experimentally investigated the structural strength of container structures. However, there was limited information on the lateral stiffness of a residential ISO container subjected to lateral load. A piece of valuable information when the container is applied to a multi-story structure. This study proposed to conduct physical tests on two full-scaled residential ISO container structures to evaluate their lateral stiffness. Considering the actual condition of a residential container, both samples were fabricated with different sizes of openings. The finite element models of the samples were developed and analysed employing Abaqus for comparison with other studies and the experimental results. The application for lateral stiffness of ISO containers subjected to wind load was discussed based on the current design standard. The outcome of the study widened the scope of the structural behaviour of an ISO container towards the lateral stiffness of a residential container structure.

Experimentally Verified Retrofit Combining Hybrid Solutions for Enhancing the Seismic Response of Multistory RC Structures

ABSTRACTThis experimental and numerical study proposes hybrid retrofit alternatives involving multiple contemporary techniques to upgrade the fundamental seismic response characteristics of multistory reinforced concrete frame (MSRCF) structures. The impact of thin high‐performance reinforced concrete (HPRC) jackets on the concrete framing system's seismic response is first investigated through shake table testing (STT). The performance of the HPRC‐retrofitted frame is then compared with another STT campaign conducted for fabric‐reinforced cementitious matrix (FRCM)–retrofitted frame. The STT results indicated that at the same input ground motion intensity that caused failure for the FRCM‐retrofitted frame, the curvature ductility and interstory drift ratio of the HPRC‐retrofitted specimen were reduced by 79% and 87%, respectively. Upon verifying the fiber‐based modeling technique of HPRC and FRCM alternatives through STT, the study probabilistically assesses the seismic performance of a benchmark MSRCF building considering different hybrid retrofit alternatives by combining each technique with a self‐centering energy dissipation (SCED) bracing system. Following a systematic seismic assessment framework, it is concluded that the performance‐cost index of the less disruptive HPRC‐SCED option exceeded that of the FRCM‐SCED by 36%, confirming its preference among the considered alternatives for upgrading the seismic response of MSRCF deficient in stiffness, strength, and ductility.

Semi-active vibration control via a magnetorheological damper and active disturbance rejection control

This work provides an alternative for the semi-active vibration control problem via state feedback plus an active disturbance rejection control (K-ADRC) for a multistory building structure equipped with one magnetorheological damper (MRD) located between the ground and the first story. This control law introduces a disturbance observer (DOB) to estimate the total disturbance in real time, produced by the earthquake perturbation, unmodeled dynamics, and parametric uncertainties, and then cancel their effect using a part of the control signal. Moreover, using a diffeomorphism, the K-ADRC provides a proportional derivative (PD) controller designed to improve internal stability. A prominent feature of the active disturbance rejection control (ADRC) algorithm is that the value of the DOB gain is selected according to the system bandwidth. The stability of the system is verified via Lyapunov analysis. Moreover, the building structure model and the MRD are accomplished by incorporating a nonlinearity state that represents the hysteresis effect to perform real behavior in addition to assuming that acceleration is the only available measurement of building structures. Thus, integral filters are provided based on the appropriate cut-off frequency to estimate displacement and velocity, avoiding bias, offset, and phase shifts. Experimental results from a reduced-scale two-story building prototype demonstrate that the proposed K-ADRC is promising for real applications, and it has better performance than the state feedback (K) and the linear quadratic regulator (LQR) control techniques.

Contribution of Torsional Vibration Modes and the Influence on Period Ratios in the Seismic Response of Elastic Plate Bent Frame Structures

The structural characteristics of large-span structures inherently differ from those of conventional multistorey structures, making it challenging to accurately describe the contribution of various vibration modes to the overall response using traditional dynamic response analysis methods. Based on the response spectrum method, this paper investigates the influence of the first torsional mode on the overall effects of large-span structures. It proposes a new metric, called the torsional mode contribution factor, to characterize the contribution of torsional modes. Focusing primarily on single-span frames, the study explores the impact of factors such as eccentricity ratio, aspect ratio, and roof stiffness on the torsional mode contribution factor. Additionally, the relationship between the period ratio and the torsional mode contribution factor is examined to assess the necessity of controlling the period ratio. The findings reveal that the contribution of torsional modes to the overall seismic response varies significantly under different conditions, such as eccentricity ratio, aspect ratio, roof stiffness, and torsional stiffness. The torsional mode’s contribution is minimal for small eccentricity ratios, with the response primarily driven by translational modes. As eccentricity increases, translational-torsional coupling becomes more pronounced, amplifying the influence of torsional modes on the overall dynamic response. The study also highlights that increasing roof stiffness and aspect ratios can mitigate torsional effects to a certain extent. Still, excessive eccentricity ratios and stiffness may result in higher torsional contributions. Additionally, it is found that increasing torsional stiffness reduces the influence of torsional modes but does not eliminate the overall torsional deformation. The proposed torsional mode contribution factor offers an effective way to quantify these effects, demonstrating that traditional control methods, such as period ratio control, may not fully capture the torsional contributions.

Sustainable multi-story building design utilizing recycled marble and ceramic waste

This study explores the design of a multi-story structure utilizing recycled waste materials. Locally produced materials from recycled sources were used for making concrete and bricks. The design of a 10-story building was carried out using ETABS software. In the process, 10% of the cement in the concrete was replaced with waste marble powder (WMP), while the bricks were made by replacing 12% of clay with waste ceramic powder and 15% with waste brick powder. The materials were developed in a laboratory, adhering to ASTM standards, and their properties were input into the software for analysis and design. The results were compared to a structure made with traditional materials. The analysis showed that using recycled materials led to the conservation of 164 tons of cement and 475 cubic meters of fertile clay while maintaining the required stability standards as per building codes. The design also prevented the release of 148 tons of carbon dioxide into the atmosphere and reduced the energy demands associated with cement production. Additionally, the building utilizing waste materials was found to be Rs. 5.8 million more economical than one made with conventional materials.

Seismic drifts of buildings through deep neural networks circumventing incremental dynamic analysis: Aims and pitfalls for robust and reliable predictions

In the field of seismic response assessment, simplified procedures have long been pursued to circumvent the rigorous, state-of-the-art nonlinear response history analysis (NRHA) and incremental dynamic analysis (IDA) that typically require tedious computations. To this end, this study investigates artificial neural networks (ANN) as prediction models to bypass IDA and quickly and reliably determine the structural drift responses of buildings, without employing surrogate models or analysis techniques that lower the quality of the estimates. Three designs of such prediction models are identified in terms of their scope, implementation and corresponding database, commonly employed in research, while identifying common pitfalls in their design. The investigations involve ten steel-frame multi-story structures, considering cyclic and in-cycle material deterioration and P-Delta phenomena. More than 17-thousand recorded ground motions (GM) are employed to perform IDA on these frame-building models, resulting in a unique database of responses ranging from linear to collapse, with more than 3-million NRHA. Based on this database, a prediction model is developed for each building, capable of predicting the IDA under a GM excitation not included in the database. Additionally, another prediction model is developed that can predict the IDA of a building under a GM excitation, both of which are not included in the database. These investigations show that ANN are excellent tools to circumvent IDA and capture the record-to-record uncertainty by rapidly and reliably predicting structural drifts ranging from linear responses to the collapse limit state, while building-to-building predictions are additionally feasible if the employed database is appropriate.

Assessment of structural performance, materials efficiency, and environmental impact of multi-story hybrid timber structures in high seismic zone

Advancements in wooden manufacture and the inherent sustainable merits of timber have stimulated studies on high-rise wooden structures and their structural performances. Considering the height restrictions of timber structures in Taiwan, two types of hybrid structure systems, reinforced concrete (RC) structure mixed with timber components, were proposed as substitution solutions to explore their feasibility and environmental impact in high seismic zones. A fifteen-story RC structure was adopted as the benchmark building, and building weight, material substitution efficiency, and embodied carbon were thus compared with the proposed hybrid timber structures after determining wind and seismic impacts. The results showed that structure system Type 1, which replaced original RC slabs and RC walls with timber, weighs only 61.3 % of the RC structure, reducing seismic forces by 38.7 % and base shear by 30.6 %, while inter-story drift ratio was smaller than that of RC structure; meanwhile, Type 2, which maintained the original RC service core and replaced timber structure for rest of the area, was only 44.5 % of the structural weight of RC structure, with a reduction of 36.4 % in seismic forces and 21.1 % in base shear. Furthermore, Type 1 featured reduced embodied carbon of 34.8 % and 35.4 % respectively using imported and domestically produced timber, while Type 2 features reductions of 47.4 % and 49.3 % respectively. The study indicated that the RC-timber hybrid structure system not only has significant structural performance in the face of the challenges of high seismic zones but also offers new solutions in terms of environmental sustainability.

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.

Comparative Seismic Analysis of Regular and Irregular Multistorey Structures with and without Bracings and Shear wall

Abstract Seismic effect is one of the main factors which has to be considered during the design of structure. Earthquake is one of the supreme hazards for living and assets on earth. It is a natural phenomenon, occurring with uncertainties as a result of sudden release of energy within earth crust in the form of seismic waves. As the earthquake forces affects the stability of the building and about 60% of region in our country is under the influence of seismic forces, the buildings are provided with alternatives to withstand the horizontal forces and to increase the strength, stability and stiffness. Present paper investigates the performance of different structures provided with seismic resisting components. In this paper Shear walls and bracings are incorporated to make the structure moment resisting frame. A comparative seismic analysis of high-rise structures with and without shear walls and bracings is included in this discussion which is done using ETABS 2019 software by Response Spectrum Analysis. The parameters considered for analysis are natural frequency, natural time period, base shear, story stiffness, story displacement and story drift. in constructing both.

Simple diagnosis for layered structure using convolutional neural networks

In this study, we propose a structural health monitoring and diagnostic method for layered (multi-story) structures using a convolutional neural network (CNN). The proposed method is a primary diagnostic one, and its purpose is to allow quick identification of the location of an abnormality after detecting it. An abnormality is defined as a decrease in the stiffness characteristics (spring constant) of the outer wall of a multi-story structure when it deteriorates or is damaged. The proposed method has the following features. A modal circle is generated by multiplying the frequency response functions (FRFs) simulated by a mathematical model and the FRFs from the actual structure, in frequency space, and then a CNN learns the features of the abnormality from the modal circle and diagnoses it in the actual multi-story structure. We first verified the validity of the proposed method by considering a three-story structure as a numerical example. When the method was applied to three types of abnormal conditions, it was shown that the abnormal diagnosis could be performed correctly. Next, we constructed an experimental model of a three-story structure, and realized three types of abnormal conditions similar to those in the numerical model. We verified the applicability of the proposed method and showed that correct diagnosis of an abnormality was possible. Both the validity and applicability of the proposed method were thus confirmed.

Experimental investigations on prefabricated interlocking prestressed tendon composite joint and its application to beam-column connection

This study proposes an interlocking prestressed tendon composite joint (I-PTCJ) that can be applied to a beam–column connection of the multi-story structure. First, the main structure and prefabrication process of the I-PTCJ were introduced. Next, three beam–column specimens using local and integral I-PTCJs (named specimens PT1 and PT2) and a traditional interlocking joint (I-J, specimen named TG1) were designed and manufactured. Furthermore, quasi-static experiments were performed on these three specimens to evaluate their seismic performance. In addition, the influence of the prestressed tendons (PTs) and the arrangement mode (local or integral) of the I-PTCJs were investigated in detail. Finally, a preliminary comparative analysis between the experimental and simulated results was carried out. The results showed that the introduction of the PTs reduced the degree of damage within the PT installation area, delayed the cracking of the interlocking interface, and improved the bond performance of the longitudinal rebar. However, it also aggravated the degree of damage outside the PT installation area and reduced the displacement ductility and energy dissipation capacity of the specimen. Compared with TG1 (using the traditional I-J), PT1 (using the local I-PTCJ) had a higher peak load, lower displacement ductility, higher shear deformation, gentler rigidity deterioration, and lower cumulative energy dissipation. Compared with PT1, PT2 (using the integral I-PTCJ) had a higher peak load, lower displacement ductility, lower shear deformation, lower cumulative energy dissipation, and better bond performance of the longitudinal rebar. Both the yield displacement angle and ultimate displacement angle met the deformability requirement of the existing building design codes. Thus, the proposed I-PTCJ can be applied to the beam-column connection of multi-story structures.

Quantitative Carbon Emission Prediction Model to Limit Embodied Carbon from Major Building Materials in Multi-Story Buildings

As the largest contributor of carbon emissions in China, the building sector currently relies mostly on enterprises’ own efforts to report carbon emissions, which usually results in challenges related to information transparency and workload for regulatory bodies, who play an otherwise vital role in controlling the building sector’s carbon footprint. In this study, we established a novel regulatory model known as QCEPM (Quantitative Carbon Emission Prediction Model) by conducting multiple linear regression analysis using the quantities of concrete, rebar, and masonry structures as independent variables and the embodied carbon emissions of a building as the dependent variable. We processed the data in the detailed quantity list of 20 multi-story frame structure buildings and fed them to the QCEPM for the solution. Comparison of the QCEPM-calculated results against the time-consuming and error-prone manual calculation results suggested a mean absolute percentage error (MAPE) of 2.36%. Using this simplified model, regulatory bodies can efficiently supervise the embodied carbon emissions in multi-story frame structures by setting up a carbon quota for a project in its approval stage, allowing the construction enterprise to carry out dynamic control over the three most important audited building materials throughout a project’s planning and implementation phase.

A soil base model of adjacent various story structures

In modern geotechnical engineering, owing to the development of information technology and availability of powerful packages for the calculation of the entire base - foundation - structure system, one of the main research areas is to develop, improve and investigate soil base models to ensure the adequate interaction between the components of the system during the construction and operation of buildings and structures (hereinafter referred to as the “structures”). The paper proposes an improved soil base model in the form of a continuous layer of finite distribution capability to simulate and calculate adjacent multistory structures in the base - foundations - structures system using powerful calculation packages such as SOFiSTiK, ABAQUS, PLAXIS, SCAD, Lira and others. The improved model considers the parameters of the stress-strain properties of the soils of the bases, the geometric profile taking account of the distribution capability of the base and different boundary conditions, but differs from the existing models in that it has a stepped geometric profile at the lower boundary of the model because of different compressible layer depths under each foundation of the structures. The use of this model improves the accuracy of simulating a soil base for large-sized foundations of adjacent structures to obtain reliable results of the stress-strain state of the base - foundations - structures system. An example demonstrates how to simulate and calculate raft foundations of a two-section multistory building in the base - foundations - structures system that interacts with an improved soil base model (linear strains of soils under loads are considered here) with reference to different numbers of stories of the sections. The numerical study results show on a specific calculation example that considering different compressible layers depths in the model under differently loaded foundations results in an increase in moment forces of up to 65% as compared with simulating the whole compressible layer, which may lead to the disruption of large-sized raft foundations.