Multi-storey Structures Research Articles

Design of a pair of isolated tuned liquid dampers (ITLDs) and application in multi-degree-of-freedom structures

The tuned liquid damper (TLD) has been proven as an effective vibration mitigation device. However, it is less efficient and robust under seismic excitations. Addressing this issue, this study proposes a dual-mode-based design methodology utilizing a pair of isolated TLDs (ITLDs) for the multi-performance vibration mitigation of multi-degree-of-freedom (MDOF) structures. Oriented by the dual-mode control target, a series of 2DOF structures were considered, and a mechanical model of the considered ITLD was established. The modal analysis was performed for the primary structure, on the basis of which feasible installation methods for the ITLDs are proposed. Correspondingly, an extensive parametric analysis and a frequency response analysis were conducted, which revealed the control advantages of a pair of ITLDs, and we explored the potential optimal design for the liquid mass and added isolation layer. Inspired by the parametric analysis results, a mode-based design procedure is proposed for a pair of ITLDs by incorporating the modal characteristics of the primary structure. Finally, the ITLDs were applied in a multi-story building structure to illustrate the effectiveness of the devices and proposed design method. The obtained analysis results show that the dual-mode mitigation effect can be satisfactorily achieved using a pair of ITLDs with the proposed design approach, as well as synthetic functionality of the pair of ITLDs. The employment of a pair of ITLDs provided effective and robust mitigation of seismic responses for MDOF structures, yielding an improved multi-response reduction compared with the TLDs with the same parameters. In particular, the seismic-excited structural acceleration responses can be suppressed for different floors, which cannot be achieved by conventional TLDs.

Response of multistory steel structure subjected to differential settlements of its foundation

PurposeThis article aims to address an outstanding problem dealing with the structure and its foundation.Design/methodology/approachDifferential settlement between foundation units of a multistory structure has been responsible for serious damage to buildings and often catastrophic failure and loss of life. The dynamic changes in the loading conditions of the structure, and the variability of the underlying ground due to environmental changes, are causing the undesirable differential settlement, which is manifested in the form of additional stresses in beams, columns and distortion of the structure elements. The structural response to the differential settlements depends on the type of the structure (concrete or steel), type of beam-to-column connections (rigid or semi-rigid), number of floors and the spans of the beams in the building. This paper presents the results of a numerical model, which was developed using the finite element technique and the software “ABAQUS” to analyze a nine-floor steel structure. The model was capable to capture the stresses and the strains developed in beams and columns and the relationships of moment–settlement and rotation–settlement for the structural during the differential settlement of its foundation. After validating of the model, data were produced for a wide range of governing parameters for rigid and semi-rigid connections and accordingly the mode of failure. The results can be used as a guideline for the design of steel structures.FindingsResults are useful for those design steel structures.Research limitations/implicationsThis study is based on the experimental and numerical data of the authors.Practical implicationsThis study provides a guideline for the design of steel structures.Originality/valueThis is the original research developed by the authors.

Shaking table test of space double-layer cylindrical reticulated shell with three-dimensional isolation bearing

Space double-layer cylindrical reticulated shells (SDLCRS) have undergone rapid development in the four three decades. Significantly different from conventional multistory high-rise structures, such structures are very sensitive to vertical actions. As a result, conventional seismic isolation techniques that aim to reduce horizontal seismic actions are notably insufficient for this kind of structure. In this study, a new three-dimensional seismic isolation bearing was developed that can simultaneously reduce the horizontal and vertical seismic responses of an SDLCRS. To examine the actual seismic isolation effectiveness of the three-dimensional seismic isolation bearing and provide important theoretical, technical and experimental support for practical engineering applications, comparative shaking table tests were performed on isolated and non-isolated SDLCRSs with lower supporting structures. The 2013 Lsf ground motion record during Lushan earthquake and the 1954 Taft ground motion record were selected as seismic inputs. The dynamic responses including acceleration, displacement and strain of the SDLCRS under the input ground motions with different amplitudes were obtained using the shaking table tests. In addition, the seismic damage of the isolated and non-isolated structures was examined to determine the acceleration amplification effect of the structures. The effectiveness in acceleration and strain responses demonstrated that the three-dimensional seismic isolation bearing was very useful for horizontal and vertical seismic isolation. Moreover, the maximum displacement responses of the bearing were less than half of the respective design displacements, suggesting that the bearing still had considerable reserve bearing capacity and could significantly improve the safety of an SDLCRS under seismic loads. The bearing developed in this study not only has excellent seismic isolation performance and post earthquake restoration capability but can also be easily installed and maintained. Thus, this bearing holds great promise for engineering applications and is suitable for SDLCRS that require both horizontal and vertical seismic isolation.

Tariff policy offers on the line of magnetic levitation transport

Background: The transport interchange hub meets its fundamental function - the concentration and organization of traffic flows of various types of transport, including individual and passenger transfers, and is of a utilitarian nature. One of the possible solutions is to place not just transfer complexes, but multi-storey structures of this kind. Where the first floor is a distribution pedestrian level, the main task of which is to ensure the transfer of passengers in a comfortable environment. On the next level there are objects of passing passenger service, the three upper floors are "intercepting" parking. With the urban area adjacent to the node, communications are provided through underground pedestrian crossings.
 Aim: The commissioning of maglev transport lines in places of concentration of growing passenger traffic, which will help to reduce travel time, meet freight needs, improve the quality and increase travel safety when driving on dedicated lanes. At the same time, it is necessary to integrate maglev transport into the transport system of cities.
 Method: The article defines the goals and objectives of the placement of transport interchange complexes. The article presents a methodology for assessing the location of transport hubs, which consists of three stages.
 Results: At the first stage, in accordance with the proposed methodology, it is necessary to carry out an integrated assessment of the territories under consideration in order to determine the prospects for their development. At the second stage, it is necessary to analyze the existing transport infrastructure in the region, providing passenger traffic in order to identify areas with the greatest transport accessibility, both in the current period and in the future. At the third stage, on the basis of logistic criteria, the analysis of the transport network in the areas with the highest passenger flows is carried out.

Response analysis of a multi-story building structure with a variety of horizontal irregularities and shear wall geometries

The growing growth of human activities has led to changes in housing patterns in urban areas. The land crisis in urban areas has made land prices uneconomical, so buildings are designed vertically. One solution to resist earthquakes in multi-story buildings is to add a shear wall structure with the proper profile and layout. Shear wall designs with variations influence the base shear, drift ratio, lateral deflection, and story drift patterns. This study presents the structural response comparison of buildings against variations in the profile and layout of shear walls subjected to earthquake loads. Force Based Design method utilizing the response spectrum approach was adopted in the analysis and carried out using SAP200. Six structural models comprise a frame without shear walls, three L-profile shear walls, two I-profile (straight) shear walls. The simulation results of the overall structural models show that the profile and layout configuration of shear walls in the frame structure of a multi-story building correlates directly to the performance of base shear, drift ratio, and story drift with relatively comparative conditions.

Comparative study of structural response on multi-story buildings with shear wall and bracing systems

Multi-story buildings are designed to withstand lateral forces against earthquakes. There are several ways to strengthen multi-story building structures. One way is to add a dual system, namely the shear wall or the bracing systems. Shear walls and bracing techniques can resist earthquake forces in vertical and horizontal directions that occur in building structures. This study compares the results of the structural analysis to three structural models. The 10- story of the structural response used in the research includes the story drift, base shear, displacement, and structural behavior due to the earthquake force. Model 1 is a general structure without the shear wall and bracing systems, Model 2 is a structure completed with L-shear walls, and Model 3 is a structure installed with the X-bracing system. The analyses of three Models were carried out by SAP2000 software. The results show that the slightest interstory drift occurs in Model 2, namely 0.041 mm. The decrease in deviation value that arises in Model 2 is 12.6 mm, with 34.35%. In Model 1, the story drift exceeds the allowable limit, so that with such a model, it is not feasible. Therefore, it is necessary to add shear walls or a bracing system.

Seismic Analysis of Symmetric and Asymmetric Structures with and without Shear wall using Etabs software

Behavior of multistory structures during solid seismic tremor relies on the underlying configurations.Irregularities are not avoidable in development of structures in light of the fact that the space accessible for building the structures are restricted consequently the structure with irregularity is built up more, because of these abnormalities in the structure damages are more during earthquake.The effect of lateral load as wind/Earthquakes influences the performance of these constructions significantly. For the stability against seismic forces of multi-celebrated structure, there is need to investigation of seismic examination to plan earthquake opposition structures. It was tracked down that principle reason for failure of RC building is due to irregular circulations of load, plan of the structures, strength, stiffness. In this paper the correlation of seismic behavior of G+15 story structures having plan irregularities was finished utilizing ETAB programming. For this reason different multi-storey structure plans are viewed as that are regular plan without shear wall, regular plan with shear wall, L shape without shear wall, L shape with shear wall, irregular plan of C shape without shear wall, irregular plan of C shape with shear wall structures. For the correlation, boundaries taken are displacement, story float and storey shear. Every one of the six structures was dissected for zone V. The fundamental objective is to contemplate the behavior of both symmetric and Asymmetric structures during seismic tremor having abnormalities in plan but the plan area is same. The another aim of the study is to examine the taken boundaries like storey shear, storey displacements, Maximum storey float of all structures that are build in this paper during seismic tremor and also to study the impact of shear wall on the behavior of different structures.

Comparative Study Of Conventional Slab, Flat Slab And Grid Slab Using ETABS

In today’s construction, the traditional slab is mostly supported by a beam, with a small slab thickness and a large beam depth, and the weight is carried from beam to column. The flat slab allows architects to place partition walls wherever they are needed. It is widely used because it reduces weight, speeds up building, and is cost effective. Similarly, since its inception, the conventional slab has provided benefits such as increased stiffness, increased weight carrying ability, as well as being safe and cost effective. Grid slabs are necessary where the span is greater, and grid beams are provided to lessen the spanning. Grid slabs reduce dead load due to voids and are appropriate for longer spans with heavy loads. The Grid slab is less expensive and provides superior vibration resistance. The project’s goal is to find the most cost-effective slab among standard slab, flat slab with drop, and grid slab. A G+5 Commercial multi-story structure with flat slab, conventional slab, and gird slab was investigated for characteristics such as storey displacement, shear force, bending moment, and storey drift in this study. There are a total of 18 structures examined. The performance and behaviour of all structures in India’s seismic zone III have been investigated with the application of dead load, live load and seismic load. The results of shear force, Bending Moment, story shear, story displacement, story drift and quantity of concrete and steel shows that the overall result values makes flat slab a suitable structure as compared to the conventional and grid slab.

Investigation on the influence of point loads on the deflection behaviour of G+5 frame structure

Nowadays, multi-storey structure portal frames are most commonly used worldwide. Multistory frames are used in structural systems in all metropolitan cities, future cities, and important businesses. The present study the effect of various point loads varying from 22 to 32 kN in steps of 2 were applied on the center of horizontal beams of the frame structure. The deflection behaviour in form of deflection, reaction, beading moments under point loading were discussed analytically according to stiffness matrix method and the results are validated with the help of simulation using STAAD Pro software. Results revealed that the analytical method using manual calculations in excel sheet provides approximately similar results as obtained by the costly simulation technique using STAAD Pro software. Therefore, the implementation of this excel sheet can be recommended for standard analysis of portal frame structures based on the outcomes of this study.

Determine the Best Location of Porch in Multistory Building with Seismic Loading

In the new era of high rise building the current job deals with the analysis, design of multi storey structure subjected to lateral load condition with different porch location . In adding up to the dead load and imposed load, the earthquake loads are applied to the structure and analysis of structure carried out. The design software staad pro software has been used for design and analysis. In the current era or scenario, a structure of G+12 situated in zone III is considered for Analysis. The Analysis is carried out for seismic zone III. The structure model are analyzed and compared with different porch location for the seismic zone III as per IS 1893-2016 for response spectrum analysis. The assessment of results is carried out for Displacement, Storey Shear, and Base Shear etc. The results are obtained and represented in the forms of graphs and tables for the seismic zone.

Comparative Study on Seismic Analysis of Multi Storied RC Framed Structure with and without Diaphragm Discontinuity

Abstract: Any Structure that is designed in today’s world has to be designed not only for aesthetics but also for stability. These days high rise multi storied structures are quiet prominent. These types of structures, should not only be designed for aesthetic point of view but also must be designed to resist earthquake forces which are subjected on these structures. These earthquake forces acting on the structures are also known as seismic forces. Due to architectural purposes, some buildings, have openings, provided in them, this creates structural discontinuities in the building. These openings or discontinuities can change the load transfer path of the structures which may cause significant change in the building behavior, under the application of the seismic forces. In this paper pushover analysis is carried out to study the behavior of the building in case of architectural opening for staircase or cut outs etc which results in discontinuity in the structure. Keywords: Diaphragm, Discontinuity, ETABS, Pushover Analysis, Seismic

Seismic Analysis of Lightweight and Conventional Buildings: A Comparative Study

Abstract: In recent decades, the use of light-weight materials over heavy-weight materials has increased at a faster rate. When it comes to cost and resource savings, lightweight construction is considered to be more essential. AAC block is a lightweight construction material that provides good acoustic and thermal insulation. In seismic zones, the use of lightweight materials in building reduces the percentage of damages. The goal of this research is to conduct a project comparison study of seismic analysis of buildings composed of lightweight and conventional materials. RSM creates a structural model of a multi-story structure (G+3) and analyses it in Etabs (Response Spectrum Method). Buildings constructed using infill AAC (Autoclaved aerated concrete) blocks and traditional clay brick masonry are designed for the same seismic hazard in conformity with Indian norms. The buildings' analytical results will be compared. The project also aims to familiarise students with Etabs2016. Keywords: Autoclaved Aerated Concrete, Conventional Brick Replacement, Lightweight Construction, Lightweight Material.

Comparative Analysis and Designing of Flat and Grid Slab System with Conventional Slab System by ETABS

Abstract: Structural Engineering is a branch of Civil Engineering in which the look at is done to recognize how the structure behave whilst building is constructed at real environment and to perceive the numerous forces like axial force and shear force, bending moment and displacement and many others.When the analysis come to complicated structure or multistory structure the guide calculation will be hard to carry out and subsequently there is diverse software available to carry out those calculations.In this examine, slab machine layout and evaluation for G+10 building for seismic zone III and having medium soil situation by the usage of ETABS V9.7.Four and those slab gadget analyzed for one of a kind plan location or grid length/ spacing of the column. Keywords: Structure Design and Analysis of slab system, Flat Slab System, Grid Slab System, Conventional Slab System, ETABS.

Robustness of multistory corner‐supported modular steel frames against progressive collapse

SummaryIn current practice, a relatively wide range of different interconnections and assembly systems is being used for the design of modular buildings made of volumetric prefabricated frames. The integration strategies and design criteria for providing structural robustness or prevention of disproportionate collapse for such buildings are completely different with those with conventional systems. This is mainly because of their fundamentally different configuration of joints and the redundancy they provide for the structure. This paper studies the robustness of multistory modular structures, made of prefabricated volumetric steel frames, against progressive collapse, which can be triggered by various column or module loss scenarios. In this study, the flexibility of modules and propagation of the damage inside the individual modules are taken into account, and the buckling of columns, as well as the effects of material nonlinearity on the responses and capacity of the entire system, are also considered. Load redistribution patterns and possible gravity‐induced collapse mechanisms are inspected in various collapse scenarios for a typical mid‐rise modular steel frame. In the numerical model, each individual prefabricated volumetric module is composed of discrete beam and column frame elements, connected through conventional rigid beam–column connections. The volumetric modular steel frames are connected via corner vertical and horizontal intermodule joints; each one is modeled utilizing one axial and two shear springs with predefined nonlinear force–displacement behavior in a 3D finite element analysis. The local damage scenarios are assumed to be due to instantaneous loss of columns or entire modules, for which the interactions between the modular units, overall structural robustness, load redistribution, possible collapse mechanisms, and progressive collapse response of the frames are investigated. The results indicate that the additional redundancy may help the modular steel frames survive from some corner column or single module removals but will not be able to maintain their robustness under combined module removal scenarios.

Evaluation of the performance of high-rise building structures with plan ‘H’ shaped for earthquake with height increase (Case study: Apartment Urban Sky-Bekasi)

Currently, Bekasi City is developing into a residence for an urban, industrial center, and built apartments. One of them is the Urban Sky-Bekasi Apartment. This researched raises by an apartment as a case study to evaluate the performance of multi-story building structures as earthquake-resistant buildings. This researched conduct by add the original building height to 8 m (a basic height equals 102 m and a new height equals 110 m) to analyze whether the planning data made could still bear the same load with different heights and could still be categorized as earthquake-resistant buildings. From the results of the SAP-2000 output. The value of the basic static and dynamic shear forces in a 110 m building is always greater than a 102 m building in both the X and Y directions, this indicates that the taller a building is, the higher the design earthquake force used will be. The displacement in a 110 m building is always bigger than a 102 m building in both the X and Y directions. The weakest strength of the structure in a 110 m building is on the 29th floor in the X directions and Y directions, while the 102 m building is on the 26th floor in the X directions and 24 directions. It shows that with the addition of high SAP-2000 output data such as displacement, drift ratio, and other data after analysis shows that a 110 m building is categorized as an earthquake-resistant building according to SNI 1726-2012.

Investigation of proposed integrated control strategies based on performance and positioning of MR dampers on shaking table

Most of the studies in the field of structural control are focused on maximizing the performance of control devices without taking into consideration the complex dynamic response of the structure, computational efficiency, performance flexibility, and feedback reliability. Also, the location algorithm of energy dissipation should be concatenated with the control strategy, for effective structural control of multi-story structures. Moreover, in recent years, non-contact measurements using digital image correlation techniques have been adopted and implemented for the monitoring of civil engineering structures. However, its application is restricted to reinforced cement concrete members, involving a lower frequency spectrum, small displacements, and a lower image capture rate. In this study two response-based-adaptive control strategies based on inter-story drift and acceleration response reduction objectives respectively have been proposed. The control strategies are then integrated with the device location algorithm to establish the optimum configuration/location of magnetorheological dampers in addition to the design parameters of the controls system. The performance of proposed strategies is numerically compared with the benchmark Genetic algorithm using the Clipped optimal controller. The corresponding results indicated that proposed control strategies performed better for high-intensity ground motion and satisfactorily for low-intensity records. Next, the shake table results validated the performance of response-based-adaptive control strategies with device allocation algorithm in alleviating the peak and RMS response of the structure. The response of the structure was also attenuated and distributed among the modes of the structure, as indicated by the fast Fourier transform response of the structure.

Behavioural Study of Infill’s Walls on Soft Story Building

Open ground storey or soft storey is a typical feature in multistory structures in urban areas. This open storey is provided to accommodate parking, reception lobbies, office, communication hall etc. Many of structure having soft storey suffered major damage and collapsed in recent earthquakes. During an earthquake, because of variation in stiffness in soft story and its adjacent floors the inter story drift can occur and the lateral forces cannot be well distributed along the height of building. Lateral forces concentrate on soft story causes large displacement. In this work, an attempt has been made to observe the behavior of gradual decrease in stiffness of building, by using different types of infill material. This work discusses Optimum Earthquake response of tall buildings by response spectrum method as per IS 1893:2002 (Part- I) in ETAB’S software. Seismic parameters like storey stiffness and storey displacement are checked out.

A Review on using Belt Truss at Different Locations on RCC Building

In past decades, shear walls and x bracing are one of the most appropriate and important structural component in multi-storied building. Therefore, it is very interesting to study the structural response and their systems in multi-storied structure during lateral load i.e earthquake loading. Shear walls and belt truss contribute the stiffness and strength during earthquakes which are often neglected during design of structure and construction. The scope of present paper is to study the effect of seismic loading on placement of belts truss in building at different alternative location. This study shows the effect of belts truss and bracing belts truss which significantly affect the vulnerability of structures. In order to test this hypothesis, RCC building was considered with and without belts truss at different location. The aim of the paper is to detail and conceptualize the varied configurations of belt truss structures system and to integrate current structures into longer structures by use of belt truss system at different location. Additionally, various advantage and disadvantage associated with outriggers and belt truss system also are discussed in this paper. A close of literature review within the field of Outrigger system is applied and therefore the summary on belts truss and gaps encountered within the study are listed during this paper. This paper introduces belt truss at different location. In which, using the belt truss structural within the RCC building so as to extend the performance of the building under the earthquake load and wind loads is studied. Concept of belt truss as Virtual outrigger is reviewed within the paper.

Dynamic response of multi-story buckling-restrained braced steel frames with different β values

The average shear-bearing ratio (β) of buckling restrained brace (BRB) is a key parameter, affecting the seismic performance of buckling restrained braced steel frames (BRBF). In order to determine the dynamic response of multi-story BRBF with different β values, two kinds of structural models are established, one is with the rigid connection of beam-column joints, and the other model has both hinged and rigid joints. The nonlinear time-history analysis of multi-story BRBF structures are carried out by selecting the seismic waves with predominant period close to the first mode period of each research model, and the seismic waves that are significantly different from it. The influence of β on the shear displacement, bending displacement and vibration mode of the structure are revealed: when β ≤ 30%, the story drift of multi-story BRBF structure is mainly shear deformation and the first vibration mode is predominant. When β increases, the bending deformation of the story drift increases. The second vibration mode of the structure is predominant when β ≈ 90%. It is suggested that the equivalent seismic force of multi-story BRBF structure with β > 30% should not be calculated by the base shear force method.

Green NOMA assisted NB-IoT based urban farming in multistory buildings

In this study, 5G- NB-IoT, enabled smart urban farming framework is presented. In order to maximize the Energy-Efficiency (EE) of NB-IoT enabled sensor network's downlink performance (deployed in urban structure), 5 G promising technology device to device (D2D) communication along with power-domain Non-Orthogonal-Multiple-Access (NOMA) principle were used and studied at two levels, i.e. NOMA-at- Base Station (BS) and NOMA-at-Edge. In the case of NOMA-at-BS, the BS transmits the superimposed signals to the NB-IoT-enabled sensor D2D pairs (termed as NOMA-D2D approach). Whereas in the case of NOMA at the Edge, in the group of NB-IoT enabled sensor nodes, the group head will transmit the superimposed signals to other group receiver sensor nodes (termed as Group-NOMA-D2D approach). These suggested solutions, ensure interference-free communication among deployed NB-IoT enabled sensor networks. The proposed approaches were implemented on the NB-IoT sensor network (deployed in balconies of two multistory building structures) and their results were evaluated through simulation. The promising enhancement in terms of sum-rate (32% to 35 %), total-energy efficiency, and fairness factor (1- 0.98) has been achieved using the Group NOMA-D2D approach in comparison to NOMA-D2D and conventional D2D approach. In addition to this, a fuzzy logic-aided solution has also been proposed for NB-IoT enabled sensor network, uplink resource grant, and post allocation resource re-utilization, this, in turn, improved the Quality of Experience (QoE) by 2–14%.