Outrigger System Research Articles

Effectiveness of Friction Damper and Outrigger System on 3d RC Frame for Seismic Loading

Effectiveness of Friction Damper and Outrigger System on 3d RC Frame for Seismic Loading

Experimental investigation and multi-hazard evaluation of viscous outriggers with amplification devices

This study proposes a novel amplified viscous damping outrigger (AVDO) to enhance the energy dissipation efficiency of a viscous damping outrigger (VDO) system. The AVDO combines the VDO with a lever amplification device, significantly enhancing energy dissipation by amplifying damper displacement. A mechanical model of the AVDO was established, and its performance was compared to that of the VDO using model tests. The experimental results demonstrated that the lever device effectively amplified damper deformation. Additionally, the damping force and energy consumption of the AVDO increased by 4.93 and 4.85 times, respectively. The deviation between the experimental and theoretical results was under 10 %, indicating that the mechanical model successfully assessed the AVDO's properties. Finally, a simulation analysis was conducted on a super high-rise structure subjected to seismic and wind loads to verify the vibration control capabilities of AVDO. The vibration-damping efficiency of AVDO was evaluated by comparing the responses of AVDO and VDO. AVDO was found to reduce top acceleration and displacement by 46.5 % and 36.8 %, respectively, under seismic loading. Additionally, AVDO reduced the peak acceleration of the top floor by 39.5 % under wind loading. AVDO effectively enhances the seismic capacity of the structure and improves the comfort of the super high-rise building. It also achieves economic savings of 79.6 % compared to the VDO at the same level of performance.

A Comparative Study Between Conventional Outrigger System and Hybrid Outrigger System considering Performance Index Criterion

Outriggers are regarded as a structural component which can effectively lessen the reactions generated by lateral loads in tall buildings. Depending on the connectivity between the core and the peripheral columns, the outrigger system can be divided into virtual outrigger system and conventional outrigger system (COS). The hybrid outrigger system (HOS) has one conventional outrigger and one virtual outrigger at two distinct floor levels. This study gives a comparison of optimal position and performance between COS and HOS based on formulated performance index criterion (PIC) for building heights of 140, 210, 280 and 350 m by considering variations in stiffness of the outrigger belt wall and beam, the stiffness of the building's core, the height of the structure and the length of the outrigger arm under static wind and equivalent static earthquake load. The outrigger behaviour assessed using PIC takes into account the combined response of displacement at top, absolute maximum inter storey drift ratio and acceleration response at the roof. Based on PIC, performance of both COS and HOS at their evaluated optimal position are compared, and is found that HOS are less effective than COS. Therefore, to enhance the performance of HOS to be in par with COS, an optimization study is performed by increasing the axial stiffness of column, stiffness of outrigger, and stiffness of slab while maintaining the increase in total concrete volume of the structure a minimum. From the findings, PIC values of HOS (PICHOS) for 40 to 100 storeys exhibits an increase of 10 to 1.1, 20.2 to 2.2 and 12.5 to 1.9% for variation in core thickness, length of outrigger arm, and outrigger thickness, respectively, compared to PIC values of COS (PICCOS). For PICHOS to be comparable with PICCOS, increase in the total concrete volume of HOS reduces from 1.4–16.5 to 0.6–2.5% as the model's height increases from 40 to 100 storeys, respectively, suggesting that the HOS with marginal increase in total concrete volume can perform effectively for taller structures.

Investigating the influences of the geometry and orientation of corrugation in the steel shear walls on the cyclic behavior through the use of finite element analysis

To dampen the loading sequences in the constructions, using the shear walls is recommended. Shear walls, which withstand the lateral forces (i.e., parallel to the plane of the wall) of wind and seismic activity, prevent buildings from collapsing while columns and load-bearing walls support the structure’s compression load all the way to the foundation. Besides, some new techniques are innovated for strengthening the structure like outrigger system. The steel shear walls are mostly used in the steel structures due to their high strength, ductility, and low weight. Recently, implementing Corrugated Steel Shear Walls (CSSWs) has gained more attention because they can absorb much amount of energy compared to flat steel shear walls. There are two important parameters in the CSSWs that play crucial roles in controlling their strength; corrugation geometry and orientation. Therefore, the current research paper aims to study numerically the effects of four corrugation geometries (trapezoidal, square, zigzag, and curved) with two orientations on the cyclic behavior of the CSSWs. Finite Element Analysis (FEA) is used to simulate the seismic loading conditions and finally, this procedure is validated through the comparison of the modeled flat shear wall with the experimentally published results. The difference between the peak loads of hysteresis curves obtained numerically and experimentally is about 8.5%. The stated FEA procedure in this paper can be regenerated by other researchers. The results confirmed the applicability of the CSSWs compared to the flat shear walls. Also, the vertical corrugation infill patterns result in higher strength in comparison to the horizontal ones. For instance, in the zigzag and square corrugation shapes, the plastic energy dissipation of the vertically oriented specimens (13.84 and 14.01 KJ, respectively) is higher around 7% and 29%, respectively than the horizontally oriented ones (12.9 and 10.84 KJ, respectively). Besides, the trapezoidal and curved corrugation geometries show the highest cumulated energy and plastic energy dissipation.

Displacement Response Analysis According to the Outrigger System Arrangement of the Twisted High-Rise Building

Displacement Response Analysis According to the Outrigger System Arrangement of the Twisted High-Rise Building

Evaluation of Lateral Load Resisting Systems in High-Rise Buildings

The rapid urbanization and the scarcity of residential space in metropolitan areas necessitate the construction of tall structures to meet the growing accommodation demands. This research paper focuses mainly on the structural act of high-rise structures under lateral loads, especially earthquake forces. Three lateral load resisting systems, namely outrigger system, shear wall at core and shear wall at corner are compared and analysed. The study reviews relevant literature, discussing parameters affecting the fundamental time period of structural models and the effectiveness of distributed belt wall systems. The research methodology involves the analysis of a 40-storey regular office building using three different lateral load resisting systems. The results obtained through response spectrum analysis, shows that the outrigger system exhibits efficient structural capability in tall buildings. The maximum lateral displacement is significantly reduced in the outrigger system compared to core shear-wall and corner-shear wall. The study concludes that enhancing lateral load resistance and providing a transition path to perimeter columns subjected to lateral load, as seen in the outrigger-system, proves effective in mitigating the impact of earthquake loads on high-rise buildings.

Static and dynamic analysis of a new offshore wind turbine system supported with outriggers

This article presents an innovative structural system for offshore wind turbines supported on monopiles. The novelty of this system lies in its enhancement of the lateral stiffness of the tubular tower through the incorporation of an outrigger system, widely employed in high-rise buildings. This novel system is modeled as a Timoshenko beam-column element under both static and dynamic loading scenarios, incorporating geometric nonlinearity and accounting for the effect of soil-structure interaction. A comprehensive numerical analysis was conducted to evaluate the system’s behavior under various static and dynamic load cases, utilizing soil data from the Red Sea region of Egypt. A modal analysis is also incorporated to investigate the eigenmodes of the proposed system. This study offers valuable insights for designers and researchers, providing guidelines and diagrams for the implementation of the proposed system.

Gaussian cross-entropy and organizing intelligence for design optimization of the outrigger system with inclined belt truss in real-size tall buildings

This research explores the optimal structural design for tall buildings with an outrigger and belt truss system. The study employs Gaussian Cross-Entropy with Organizing Intelligence (GCE-OI), a novel optimization approach that utilizes a self-organizing map as a machine learning algorithm, and Gaussian probability distribution in Cross-Entropy optimization. This approach is used to predict promising solutions and to guide the search process for swift convergence. The optimization encompasses member sizing (weight) and outrigger placement (topology) while introducing inclined belt trusses alongside traditional horizontal trusses for enhanced performance. The process involves optimizing a 25-story real-size model subjected to wind load, and the results are compared against multiple well-known algorithms. The results show that the proposed optimizer, supported by machine learning, outperforms alternative algorithms, offering superior solutions with enhanced convergence. Considering the efficiency of the inclined belt trusses and the proposed robust optimization method (GCE-OI), the optimally-placed outrigger system minimizes the constructional cost and enhances structural stability by limiting the responses.

Height-posture and load coupling control methodology of URAPM and its application in active suspension control of multi-axle vehicles

Unidirectional redundant actuated parallel mechanism (URAPM) is the physical prototype of active suspension system, truck crane outrigger system, etc. As the number of adjustment mechanisms (AMs) increases to more than three, the difficulty of height-posture control of the upper component (UC) increases considerably. The AMs load control is also tough but highly underappreciated, which in turn causes height-posture disturbance. In this work, a convenient height-posture and bearing load coupling control methodology and its application in the active suspension system are presented. Firstly, by characterizing the force-deformation coupling relationship of the URAPM, a basic geometry and load coupling control model is proposed. And for the desired bearing load control, different optimal load allocation algorithms are developed and evaluated. Secondly, coupling control models for the flexible load control under stationary height-posture, and the flexible height-posture control under balancing load are constructed respectively. Finally, bench tests based on a six-legged URAPM (equivalent to a three-axle active suspension vehicle) validate the proposed method can achieve high precision, high convergence, and most attractively, the height-posture and load coupling adjustment with few iterations, thus demonstrating its good application prospect in low-speed off-road maneuvering of multi-axle vehicles and other related fields.

Enhancing Seismic Performance of Semi-Commercial Apartment having Telecommunication Tower at Roof

Abstract: When studying the impact of seismic activities on a structure, we focused on the efficient case and didn't consider the worst-case scenario. If a telecommunication tower is planned on a multistoried building in the future, and the tower is in the worst possible location, certain measures need to be taken to stabilize it and adjust the parametric values. In this research, we analyzed a total of 5 semi-commercial apartment building cases with G+19 floors, each having different telecommunication tower locations. After the analysis, we identified the worst case and implemented an outrigger system, as discussed in the graphical representations in the discussion section. In conclusion, we compared parametric results and observed that Case TTD is very efficient, while Case TTA is the worst among all the cases. We also improved the stability of the worst-case TTA and transformed it into Case TTO through the implementation of the outrigger system, as indicated by our results and discussions.

Application of amplified damped outrigger in seismic design of high‐rise buildings

SummaryThe application of the outrigger technology effectively improves the lateral stiffness of buildings, reduces harmful deformation, enhances the seismic resistance of structures, and contributes to the rapid development of high‐rise buildings. To improve the response speed and energy dissipation of a viscous damping outrigger under seismic excitation, a viscous damping outrigger with an amplifier was proposed, and its effectiveness was verified by combining it with the seismic design of a 149.2 m high‐rise building in an 8.5‐degree intensity area. To determine the additional damping ratio of the building structure, investigations were carried out using both the code method and energy ratio method to evaluate the contribution of the damping outrigger. The damped outrigger equivalent stiffness determination method was studied, and the simplified engineering calculation method was compared against the refined finite element analysis results for engineering design purposes. The displacement amplification technique incorporated into the viscously damped outrigger can enhance the damper response speed, and increase the energy dissipation of the damped outrigger system. The application of an enlarged damped outrigger in engineering can result in an additional damping ratio of approximately 1% while simplifying the calculation method based on the additional damping and equivalent damper cut‐line stiffness, which can be useful in engineering design.

Analysis Of Frame Structure Subjected To Lateral Load By Using Lateral Load Resisting Elements

When it comes to controlling excessive drift, efficiency, and rigidity when exposed to lateral loads, multi-story constructions are among the most popular choices for the outrigger system. Both structural and non-structural forms may have their damage reduced in the event of an earthquake or wind stress. The purpose of this article is to examine the importance of creating a three-dimensional model of a 32-story building in order to conduct analyses and designs using the ETABS program. The model will be used to analyze the building's frame structure and determine the elements that will resist lateral loads. The purpose of this experiment is to determine the impact of an outrigger system at one, two, three, and four storeys in height. This model study makes use of the Wind Static Method, the Linear Dynamic Method (Response Spectrum Method), and the Linear Static Method (Equivalent Static Method). Determine the lateral displacement, base shear, and tale drift for various kinds of models with and without an outrigger system using the efficiency and stiffness parameters. Therefore, in this scenario, it is necessary to reduce displacement and drift in comparison to the model without the outrigger system.

Feasibility of outrigger structural system for tall timber buildings: A numerical study

Tall timber buildings are prone to serviceability problems (e.g. lateral displacements and wind-induced accelerations). This article investigates the feasibility of timber outrigger system to build up to 20 storeys using linear elastic finite element analysis and relevant European and international standards such as EN 1990, EN 1991-1-1, EN 1991-1-4, EN 1995-1-1 and ISO 10137. The location of up to two outriggers was optimised based on different serviceability criteria. Various outrigger layouts were investigated, and their stiffness demands were discussed. The efficiency of outrigger structures in reducing lateral displacements and wind-induced accelerations is highlighted. A feasibility study considering serviceability requirements was performed using different basic wind velocities, number of storeys and gravity loads. Although the focus of the article is on serviceability requirements, some ultimate limit state considerations (forces and stresses) were briefly discussed. The results demonstrate the feasibility of building up to 16 storeys under medium to high wind velocities.

Influence of slab structure on the behavioral analysis of hybrid outrigger system

SummaryOutriggers are internal structural systems used to enhance the stiffness and strength of high‐rise structures. This research investigates the efficacy of a hybrid outrigger system (HOS) which consists of one conventional and one virtual outrigger at two distinct floor levels in high‐rise RCC buildings. A non‐dimensional quantity, ϒ, defined as the relative stiffness ratio between the core and the diaphragm is used to describe variations in the stiffness of the building's core, stiffness of floor diaphragm, breadth, and height of the structure, in the behavioral analysis of the HOS. To investigate the efficacy and optimum locations of the hybrid outriggers, static and dynamic analysis are carried out on models with four‐story heights of 140, 210, 280, and 350 m under static wind loading, uniform wind loading, equivalent static earthquake loading, and dynamic earthquake loading. Results are assessed based on the responses from roof displacement (Disptop), base bending moment, roof acceleration (Acctop), fundamental period, and absolute maximum inter‐story drift ratio (ISDabs.max). Based on the minimum responses of the aforementioned dependent parameters under wind and earthquake excitations, the corresponding optimum locations of hybrid outriggers are investigated. To investigate the impact of the slab on the functionality of the HOS, the behavior of shell stress variation in the tension and compression side of the slab at the outrigger floor level and the force transmission through the column at the outrigger level is analyzed. Also, the optimum location of the hybrid outriggers based on the ideal performance index (IdealPI) is investigated. IdealPI is defined as a parameter that considers the combined response of Disptop, Acctop, and ISDabs.max and the criteria required for the structure under wind and seismic loads. From the behavioral analysis results, it is found that an increase in the stiffness of the slab showed an improved performance of the HOS compared to an increase in the stiffness of the core, and HOS performance can be maximized by increasing both thickness of the slab and outrigger arm length. The findings of the optimum location analysis could serve as a guide for structural engineers when selecting suitable positions for hybrid outriggers in high‐rise structures.

Assessment of mitigation alternatives for differential shortening in high-rise reinforced concrete buildings

Selecting appropriate structural system for reinforced concrete (RC) buildings is essential in the design process to satisfy serviceability and strength requirements. Using ordinary analysis (OA) may result in inaccurate estimation of differential shortenings (DS) between vertical supporting elements which might lead to structural and architectural problems. Efficiency of staged analysis including time-dependent effects (SAT) has been recently recognized for the analysis of these buildings due to considering the sequential nature of construction. In this research, eight RC buildings with heights ranging between 35 and 175 m and various structural systems, namely rigid frames (RF), shear walls (SW), wall frames (WF), and tube in tube (TT), are analyzed. An assessment is conducted for the adequacy of three mitigation alternatives to decrease changes between DS estimated using OA and SAT. In Alternative 1, cross sections of all vertical elements (columns and shear walls) are increased by 50%. Alternative 2 is performed by iteratively proportioning the dimensions of internal columns without changing the cross sections of edge and corner vertical elements. One outrigger system is introduced along the height of buildings with WF and TT systems in Alternative 3. Analysis of the eight buildings is implemented by developing a numerical model considering the construction stages and time-dependent effects. The alternatives assessment is conducted by comparing differential displacements (DD), bending moments, and shearing forces before and after mitigation obtained from OA and SAT. The numerical results showed that Alternative 1 is not efficient in mitigating the differences between the OA and SAT for all the studied buildings. However, an optimum solution can be achieved using the Alternative 2 for all investigated systems. Also, Alternative 3 was found adequate in partially mitigating the differences between the two analyses for the buildings with WF and TT systems.

Analysis on the Behaviour of Hybrid Outrigger System in Relation to the Frequency Content of Earthquakes

Analysis on the Behaviour of Hybrid Outrigger System in Relation to the Frequency Content of Earthquakes

Effective Location of Different Outrigger System in Seismic Respond RCC High Rising Building Using ETABS

Abstract: The rapidly growing number of high-rise structures around the world poses new obstacles, and lateral stiffness becomes one of the most critical issues as building height rises. The lateral stiffness and resistance capacity of high-rise buildings have a significant impact on structural efficiency, and structural engineers have introduced numerous capable constructions. The outrigger system is one of the most frequent and effective lateral loads resisting structural systems for improving structural stiffness and stabilizing the structure. The core shear wall provides structural strength in the main structural system, while the outrigger like X bracing adds lateral stiffness. In this study building with the outrigger and shear wall system has been analysed by Response Spectrum Analysis, The concept of illumination of outrigger structural systems is evaluated by comparing multiple X braced outrigger system and shear wall system models types utilizing a 25-story reinforced concrete building using ETABS software under seismic load to better understand the performance and load transferring mechanism of outrigger system.

Energy Analysis of a Damped Substructure Outrigger System

A damped outrigger system (DO) has been proposed to enhance the seismic performance, in which links between outriggers and perimeter columns are artificially disconnected and implemented by dampers. Such an operation essentially destroys the structural integrity and becomes a potential threat for structural safety. Moreover, its performance is very sensitive to the stiffness of perimeter columns. In this study, a mega-sub controlled system is employed to propose a novel outrigger system, i.e., a damped substructure outrigger system (DSO). The novel system has good structural integrity due to its main structure consisting of the core tube, outrigger, and perimeter column. To present further investigation, the govern equations of DSO are derived by the simplified model which is regard as a cantilever beam system with a multirotation spring and energy dissipation substructure. Then, the energy distribution and seismic performance are parametric investigated. Finally, the damping effects of DSO are discussed. The results indicate that DSO possesses the superiority of damping performance. Compared with DO, DSO is less sensitive to perimeter column stiffness. Moreover, the proposed system can obtain the high efficiency in energy dissipation but with less damping cost than that of the viscous damper. Also, the larger stroke of the viscous damper can be found for DSO.

Seismic Response Analysis of High-Rise Reinforced Concrete Buildings Using Outrigger System

Seismic Response Analysis of High-Rise Reinforced Concrete Buildings Using Outrigger System

A Study Performance of Conventional Structure and Outrigger Structure with Dampers in Seismic Zone IV and V

This study compares the seismic performance of a conventional high-rise building, designed following standard codes, with an outrigger structural system featuring additional lateral resisting elements like outriggers and friction dampers. The aim is to assess the effectiveness of the outrigger system in reducing seismic forces in high seismic zone IV, zone V and enhancing overall building performance. Through seismic analysis using ETABS and comparing in storey displacement results. The findings will offer valuable insights to aid engineers in making informed decisions for seismic-prone regions, leading to safer and more resilient high-rise structures. Key Words: conventional structure, outrigger structure, friction dampers, static and dynamic analysis (Response spectrum method)