Multi-storey Structures Research Articles

Design and Analysis of a Corporate Office by Using Post Tension Methods (Stilt+12Floors) with cost Analysis of Conventional Slab and Post-Tensioned Slabs

Abstract: The assignment manages with the Design and Analysis of Corporate Office structure with post-tensioned Slabs. The development has been arranged and taken apart for the customary floor. The drawings and various subtleties are inspected with Structural Consultant concerning National Building Corporation (NBC). Fundamental format is the fundamental piece of primary planning. In aggregates, etc on extra making we used the admixtures and plasticizers, etc. Along these lines, the advancement materials are changing from regular daily existence. In past times, the designs are worked with just ground floor in a manner of speaking. i.e., free house. In this undertaking we have arranged and analyzed constructed Stilt+12 floors and OHT. In different seismic zones to really investigate the changed limits because for deficiency of land and budget of land is profound and other most item is the urbanization, etc. For the improvement of the multi-story structures Offices, as of now a days we are moving to Pre-Tension and Post Tension systems, and variety in cost for regular piece and tensioned techniques chunks

STUDY ON BEHAVIOUR OF DIAGRID STRUCTURE FOR DIFFERENT DIAGRID ANGLES WITH CONSTRUCTION SEQUENCE ANALYSIS

It is frame work of diagonally intersecting metal, concrete, or wooden beams i.e. used in the construction of building and roofs and its diagonal components can carry both gravity and lateral loads due to their trigulated design and axial actions. Construction sequence analysis is a non linear analysis approach in which the structures in analyzed at various stages corresponding to the construction sequence and partially required loads are applied sequentially at every stage. A plan of 20 m × 20m size was considered. ETABS 2016 was used in modeling and analysis of structural members and subjected to seismic loads for zone V as per IS1893-2016. In total 6 models with different diagrid angles (520 620 & 680 ) and column removal scenario at different floor levels. To study bending moment and shear force variation in transfer girder beams for with and without construction sequence and study axial force variation in columns for with and without construction sequence analysis & also study seismic response of diagrid structure with different diagrid angles i.e., storey displacement and storey drift. For response spectrum analysis when compared different diagrid models (620 and 680), diagrid model 680 is less displacement as compared to other degrees implying that we take above 680 diagrid angle is best for tall buildings. A more realistic design than the standard design is produced by including sequential load case in the study of multistory RCC structure. Key Words: Diagrid angle, construction sequence analysis,

STUDY OF PROGRESSIVE COLLAPSE ON MULTI-STORIED STEEL STRUCTURE

Progressive collapse is a catastrophic chain reaction of failure initiated by loss of vertical bearing load element of the structure resulting in damage of a part of the structure or entire structure. In the current study, it is intended to investigate the progressive collapse potential of multi-storied steel structure according to IS 1893:2002. The buildings include regular and irregular plans of total 5 models with column removed at three different locations at first storey in order to study consequences and check safety of adjacent members. Pushover Analysis is also conducted for all the models. The seismic response of steel structure in terms of performance point and the effect of earthquake forces on multi storey building with the help of pushover analysis is carried out in this paper. Modelling and Analysis of the buildings are performed using ETABS 2017. Key Words: Progressive collapse, DCR ratio, Pushover Analysis, Performance point, Hinge Formation

Seismic performance of a steel frame structure with dissipative cladding connections

In this study, a dissipative connection system for multistory steel frame structures is proposed, in which two bearing connectors are located at the top and a metal yielding dissipative connector (i.e., tapered connector) is located at the bottom of a large panel. Quasi-static test was conducted to investigate the performance of individual connectors first. Then two steel subassemblies, one having a steel frame with a large cladding panel and the other as its counterpart, a bare frame, were prefabricated and tested under quasi-static loading. Effect of the cladding panel and the proposed connections on the seismic performance of the steel frame was evaluated. It was indicated that the damage of the tapered connector was caused by the rupture of one energy dissipation plate during the fatigue loading and the hysteresis behavior of the connector was affected by the membrane effect. The proposed energy dissipation connector can improve the strength, stiffness, especially the energy dissipation capacity of the subassembly. However, the failure of both subassemblies was mainly caused by the yielding of the column foot and buckling of the beam end, therefore the cladding panel did not change the damage pattern of the steel frame. Three-dimensional (3D) finite element (FE) analysis was conducted to reproduce the tests of the connectors and the subassemblies, facilitating a better understanding of the working mechanism of the system.

STEEL SEMIRIGID STRUCTURES ENERGY STATE UNDER SEISMIC ACTIONS

Intended contribution proposes an energy-based approach to the assessment of capability of semirigid multi-storey steel structures to dissipate seismically induced energy via semirigidly connecting zones of the structure. The energy state of multi-storey structure is defined in terms of the energy balance equation. Total amount of seismically induced energy is divided into its classic components: kinetic energy, strain energy and dissipated energy. Dissipated energy is - in its turn - split into the amount dissipated by the structure itself (Eds) and the amount dissipated by the semirigidly connected zones (Edc). The last is computed as the equivalent of work performed by the bending moments associated to the semirigid connections through the relative rotations of the connections. Proposed procedure is further illustrated by several dynamic / seismical analyses of one multi-storey steel structure subjected to two reference earthquakes. Beam to column semirigid connections is of top - and seat - angle with double web-angles (TSDW) make up in several degrees of initial stiffness. The bending moment - relative rotation of semirigid connections are governed by Kishi - Chen relation. Obtained numerical results are presented into a comparative graphical manner. Short comments and conclusions end the contribution.

PUSHOVER ANALYSIS IN SAP 2000 USED IN THE SEISMIC ANALYSIS OF A LIVE PROJECT MULTISTOREY BUILDING

The research was carried out for a live (G+5) structure. SAP2000 finite component software was used to analyze the building. Due to high land prices and a scarcity of land, multi-story structures are widespread in India. Seismic is a marvel that has the power to ruin huge constructions. Structures should be designed from the bottom up to be safe for people's lives, with the appropriate style and features, in order to have a flexible and reasonable disappointment. The primary purpose is to construct a tremor-resistant structure by performing a business seismic investigation, establishing the look with a static comparable research strategy, and analysing and planning the structure using SAP2000. As a result, all zones (II, III, IV, and V) were calculated by checking the structure's reaction and behaviour using its base shear, structural deformation, and performance curve. Keywords: - Seismic Analysis, Story Drift, Story Displacement, Performance Curve, Structure Deformation, Base Shear

Diagrid Mono Column Structures with Different Geometry in Plan: A Review

Abstract: Due to increasing urbanization and rapid infrastructural development, scarcity of land is a problem. Multi-story structures have been constructed to eliminate this problem. But for the requirement of large service spaces and good aesthetic appearances, the mono column structural system achieved popularity. Mono column structures are complicated since the mono column supports the whole structure and all other member acts as cantilevers. Mono column structures are vulnerable to seismic loads and adding a diagrid structural system on the periphery of the building improves seismic performances. This review paper aims to review the previous studies on mono column structure and diagrid structural system. It also focuses to review the performance of different plan geometry buildings.

A Review on Base Isolation of Multi-storied Steel Structure

Abstract: When designing buildings and structures in earthquake prone area, a designer has to provide a predetermined level of reliability and earthquake resistance to structure. Apart from traditional seismic methods for earthquake resistance, analysis of steel braced steel buildings using designed base isolator has to be done which is effective. A seismic isolation is one of the most popular and effective method to protect structure against strong dynamic actions. For such analysis, ETABS software is generally used.

Analysis of Building Constructed on an Inclined Surface Considering Different Parameters of Soil Types

Abstract: This study draws attention on proper planning and construction practices for multi-storied buildings on sloping ground. However, in usual design practice the designers generally ignorethe behavior of the building due to the effect of sloping ground. The evaluation of a G+4 storey RCC structure on varying sloping angles (00 , 150 , 200 , 250 , 300 and 400 ) were studied and also compared with the flat surface. The evaluations of the structure were carried by the software STAAD Pro v8i to study the effect of slopes on building performance. The evaluation was done to figure out the effect of sloping ground on the forces applied on the structure. Soil interaction must be suitably believed from design point of view. The Research work triesto find the truth about the earthquake-related behavior of multi storey structures on sloping angles thinking about soil-structure interaction. The horizontal reactions, bending moment in footings and axial force, bending moment in columns were critically studied to put the effectsof different sloping ground. It has been followed that the footing columns of lower height attract more forces, because ofa big increase in their stiffness, which in turn increases the horizontal forces and bending moment. So, the section of these columns should be designed for changed forces due to the effect of sloping ground. It draws attention to the need for proper analysis and designing of the structure resting on sloping surface. Overall movement of the structure with respect to different sloping ground setups is also carefully studied.

Numerical Study of Hybrid Through Plate Connections to CFST Columns

The use of concrete-filled steel tube (CFST) columns is highly encouraged nowadays in modern multistory structures. The major reason is the extensive resistance offered by the hollow steel column to high compression. Nevertheless, further studies and data are desirable to exhaustively characterize these members and their connections to other members, such as beams. This paper investigated the behavior of concrete-filled columns connected to I-beams by through plates. Three simple types of plate connections (easy to assemble and construct) were proposed and evaluated. The behavior of these connections was examined under static loading by using advanced finite element based software (ABAQUS). The modeling techniques used in this study were validated by comparing the numerical results of a through plate connection model with the results of two relevant experimental studies. The proposed connections were classified as semi-rigid connections according to Eurocode-3. These connections were able to move the plastic hinge away from the column panel zone. The maximum plastic rotations of all connection types were greater than 40 mrad. The failure mode, and moment-rotation curves of the concrete-filled column to steel beam connections were discussed based on numerical results. The influence of through plate material and through plate thickness were evaluated via a parametrical study.

Evaluating Laboratory Measurements for Sound Insulation of Cross-Laminated Timber (CLT) Floors: Configurations in Lightweight Buildings

Cross-laminated timber (CLT) floors with supplementary layers or floating floors comprise a common solution in new multistory timber structures. However, bare CLT components provide poor sound insulation, especially in low frequencies during structure-borne sound propagation. Thus, floor configurations in wooden buildings deploy more layers for improved acoustic behavior. Twelve contemporary CLT floors were analyzed after laboratory measurements of airborne sound reduction and impact sound transmission utilizing the following indicators: Rw, Rw, 100, Rw, 50, Ln,w, Ln,w,100, and Ln,w,50 (per ISO 10140, ISO 717). An increase in sound insulation was achieved thanks to added total mass and thickness, testing layers of the following: elastic mat for vibration isolation, wool insulation, gypsum boards, plywood, concrete screed, and wooden parquet floor. The results indicate that multilayered CLT floors can provide improvements of up to 22 dB for airborne sound and 32 dB for impact sound indicators compared with the bare CLT slab. Floating floor configurations with dry floor solutions (concrete screed) and wooden parquet floors stand out as the optimal cases. The parquet floor provides a 1–2 dB improvement only for impact sound indicators in floating floor setups (or higher in three cases).

Performance of clutched inerter damper for base-isolated structures under near-fault motions

The performance of the supplemental clutched inerter damper (CID) for the base-isolated multi-story structures subjected to near-fault earthquakes is investigated. The isolation system is considered as lead-rubber bearings with bi-linear characteristics and viscous damping. The resisting force of the CID is proportional to the relative acceleration between two terminals under the attached condition and zero when detached. The governing equations of motion of base-isolated structure and the CID are derived and solved using numerical techniques under seven near-fault ground motions data. The variation of peak bearing displacement, top floor absolute acceleration, total base shear, and the CID force is plotted against the inertance mass ratio of the CID. The above peak responses were also analyzed for different values of damping, period of isolation, yield strength of LRB, and superstructure stories. Application of the CID is observed to effectively facilitate the reduction in bearing displacement while the combined effect of isolation and the CID prevents the top floor acceleration to shoot up. The optimum value of inertance mass ratio is also determined by minimizing the total base shear which is the measure of equivalent lateral force on the structure. The optimum inertance lies in the range of 35%–45% of the total mass of the isolated building under near-fault motions. In addition, the performance of the CID base-isolated structure subjected to cycloidal pulses is also investigated. It is observed that the CID is quite effective in controlling the displacement of the isolation system under cycloidal pulses.

Numerical Study on Seismic Behavior of Flexural Frames with Semi-Rigid Welded Steel Connections Considering Static and Reciprocating Loads: A Performance-Based Earthquake Approach

This paper aims to apply a performance-based earthquake engineering approach to assess the assurance of flexural frames whose members are jointed together by using new modified RBS connections, namely, semi-rigid welded steel connections, which obey a progressive failure mechanism. First, the structural members and connections are modeled and predesigned in ETABS software, and then, using OpenSees software, a series of nonlinear progressive failure analyses are performed on the built models extracted from ETABS. To this end, three types of multi-story structures with 3, 10, and 15 are modeled. The models are subjected to 15 earthquakes, such as Northridge (1994), Kobe (1995), Chichi (1999), Bam (2003), Tabas (1978), and so on. The connections are modeled by a series of rotational springs whose nonlinear behavior is estimated by a three-line curve that is established based on the modified Ibarra–Krawinkler deterioration model. Finally, obtaining the maximum ground acceleration versus the maximum relative drift of the floors, the fragility curves of the structures for a collapse level (CP) are determined, through which the seismic performances of the models are evaluated. The results show that by reducing the number of structural floors, the ductility of structures was reduced, and by increasing the ductility of structures, higher drifts in structures were achieved at the same seismic level. The average amount of ductility reduction coefficient in structures with RBS was 1.06 times those without RBS, which indicates that the energy dissipation capacity in structures without RBS connection is higher than in those with RBS. Local analysis of connections shows a 9% increase in the plastic rotation capacity if RBS connections are used. The ductility of all frames with RBS connection increased slightly compared to frames without RBS.

Determination of response of multistorey structure subjected to blast loading

Determination of response of multistorey structure subjected to blast loading

On the Seismic Resilience of Interwar Buildings

Abstract This paper deals with multi-story buildings erected mostly in interwar period in seismic areas and designed for gravitational actions only. The typical structural system is reinforced concrete frames and masonry infills. A usual multi-story interwar structure was chosen in order to evaluate its seismic resilience. There were made in situ measurements for its dynamic characteristics. The numerical model was calibrated according to in situ measurements. There were proposed two methods of increasing the seismic resilience. First method consists in improving the resilience by reshaping without reinforcing. The second method is additional to the first. It consists in reinforcing infilled frames in order to take over seismic loads.

Collapse mechanisms of multi-story steel-framed modular structures under fire scenarios

Modular building is an innovative construction method and imposes unique assembly requirements. Modular structures may exhibit different global responses and unexpected resisting mechanisms under loading scenarios. However, there is limited research dealing with collapse behavior of steel-framed modular structures exposed to fire. This paper studies numerically the fire-induced collapse behavior of the modular framed steel structures. A six-story modular structure is designed. Finite element analysis is conducted to investigate global deformation, load transfer pattern, structural resisting mechanisms and collapse process of the structures exposed to fire. A series of parametric analysis is conducted to study influences of load ratio, cross-sectional dimensions of columns and fire locations. Results show that the modular structure designed based on Hong Kong building code survives against single module fire, but collapses during traveling fire. The overturning action, bracing effect and double-beam system are developed under fire scenarios. A geometrically unstable system is developed against traveling fire. Moreover, damage spreads from the columns close to the fire compartment to those far away. The robustness of modular structures is greatly influenced by its load ratios and cross-sectional dimensions of the columns. The findings can be adopted as valuable tools for recognizing the vulnerable structural components and critical loading mechanisms of modular structure exposed to fire. A practical design method is proposed to evaluate the final collapse state of the modular structures exposed to fire with good accuracy and efficiency and this provides a practical solution for the structural engineers to process the collapse state of modular structures.

Pull-down test and numerical validation of multi-story steel moment frame using pulley-based loading system

Regarding the structural robustness against progressive collapse, recent studies have revealed that the catenary effect is the critical resisting mechanism for the frame structures under large vertical displacement. The previous studies of the single floor beam-column subassemblies suggest that the catenary effect is greatly affected by the connection performance as well as the horizontal restraint. However, the conventional push-down testing might not appropriately represent the horizontal constraint from the surrounding bays and the vertical loading condition under the uniformly distributed gravity loads. Therefore, the static pull-down test is performed on the multi-story steel moment frame equipped with straight-reduced-section splice plates (SRSP). It is used for high deformability of beam-to-column connection. In addition, a vertical loading system using the fixed pulleys for load transferring is newly proposed for a feasible and safe loading procedure. The experimental results show that the growth of vertical resistance can be mainly attributed to the plastic hardening and the consecutive catenary effect. The maximum resistance is governed by the first rupture of SRSP at the overall chord rotation of 0.178 rad, indicating high deformability of bolted connection with SRSP. Based on the failure sequence of connections and the internal force as well as deformation response, the floor dependency of catenary effect can be significantly observed. It is characterized by the earliest failure emerging at the 1st floor, followed by the consecutive ruptures observed at the upper floors. In terms of the internal force, the vertical contribution derived from the tensile force will be gradually rising for the connection at the 1st floor, in contrast to the negligible catenary effect at the 2nd and 3rd floors. Eventually, the numerical simulation is performed based on the previously proposed material model. The simulated full-range force-displacement curve with the low percentage error of 0.8% for the first rupture displacement demonstrates the validity of the numerical model in terms of the full-range behaviors of multi-story frame structure.

Hierarchical model predictive vibration control for high‐rise structures using semi‐active tuned liquid column damper

Vibration control for high-rise structures has become more important as buildings become more lightweight. Tuned liquid column dampers are an established approach for this problem, as they do not consume high amounts of energy while achieving high damping forces. The natural frequency of tuned liquid column dampers (TLCDs) can be changed semi-actively by modifying their column geometry. As shown by previous studies, this approach increases the control performance of the damper and allows a larger application field. However, this modification simultaneously provokes strong nonlinearities, which need to be addressed for controller design. In this contribution a model-based controller for such TLCDs is proposed, which explicitly accounts for the nonlinear dynamics of the coupled system consisting of a multi-storey structure with a semi-active TLCD. To account for various system dynamics of the structure, a hierarchical nonlinear model predictive controller (NMPC) in combination with a multi-start strategy is formulated. In addition, an extrapolation algorithm is developed to determine an approximation of the future trajectory of the structure's induced excitation load. The excitation trajectory is then incorporated in the NMPC framework. For validation, a frequency response analysis and a case study are conducted on a 20-storey benchmark structure, which is equipped with a semi-active TLCD. The study is carried out in simulation, and the results are compared with passive vibration control. With the proposed hierarchical control, a significant improvement is shown in the reduction of structural vibrations over the relevant spectrum of excitation frequencies up to a mean of 50%.

Structural Analysis of Asymmetrical Multistory Building with Watertank Act as a Seismicdamper

Overhead water tank commonly used in buildings for various requirements. Overhead water tank is not only for water supply which also control the displacement of building during the earthquake force acting on structure. RCC over head water tank which gives the certain mass to the building this mass reduce the lateral movement of the building during seismic force on structure. In multi story structure, water tank also will lead the important factor for reducing the seismic response of the building. Using this technique overhead water tank placed on asymmetrical multi story building at different places. In thatone particular location reduce the seismic response more that place is choose for placing water tank. The advantage of this method isoverhead water tank is used for water supply as well as controlling of seismic response. Response spectrum analysis are used for analysis the structure in ETABS software. This software is used to checking the particular location for fixing the overhead water tank.IS standards are used for this analysis. In this experiment purpose the G+10 building is analysed in this study. This method is very economical it save the extra money for strengthening the building.

To Evaluate the Seismic Response of a Building Having Stiffness Irregularity and Plan Irregularity with Quintuple Friction Pendulum System

Abstract: Quintuple friction pendulum (QFPS) bearing is a new generation sliding isolation system having multiple spherical sliding surfaces. The friction isolation system with single sliding surface is designed for a specific level of ground shaking, which may prove ineffective in case of other hazard levels. The QFPS bearing on the other hand, exhibits adaptive behavior and imparts greater amount of flexibility to the designer for various levels of earthquake shaking. Here, the effectiveness of Quintuple Friction pendulum system is carried out to study the seismic demands of base-isolated building frames with stiffness irregularities and plan irregularities subjected to various earthquake ground motions i.e. Far field ground motion, near field ground motion with fling step and near field ground motion with forward directivity by comparing their estimates with the benchmark responses obtained by the Non-Linear Time History Analysis (NLTHA). SAP 2000 Software has been used for the same. The two soft storey buildings and two buildings with plan irregularity will be modelled and analyzed. The seismic demands namely, Inter story drift, peak storey acceleration, maximum base shear are considered for the study.The reduction in absolute acceleration is found more in case of PI as compared to SS for all the considered time histories. The reduction in Maximum Base-Shear is found more in case of Plan irregularity as compared to Stiffness Irregularity (Soft Story) in all the considered Time History. In isolated structure, the Inter-storey drift is found to be maximum in case of structure having soft storey as compared to plan irregularity 1 and 2. Keywords: Multi storied RC structures, Plan irregularities, Soft storey, Quintuple Friction Pendulum, Non linear Time History Method(NLTHM)