Super High-rise Structures Research Articles

Experimental and analytical study on CFST column-steel beam joints with stiffening ring and stirrups under high axial compression ratio

Super high-rise structures frequently employ concrete-filled steel tubular (CFST) column-steel beam joints with stiffening ring because of its superior performance. This study examined the structural behavior of high axial compression ratio stiffening ring joints with stirrups in the column. Three 1/2-scaled joints with different stirrup arrangements and axial compression ratios were designed and tested. Apart from analyzing the hysteresis behavior, skeleton curve, stiffness degradation, energy dissipation, and steel strain of each specimen, an investigation was conducted into the failure mechanisms of the specimens under low cycle reciprocating load on the beam end. Furthermore, a three-dimensional nonlinear solid finite element (FE) model was developed for the joint. The results of the FE analysis and the experimental data agreed well regarding failure modes, hysteresis curves, and steel strain. Furthermore, the energy dissipation allocation mechanism of joints with various parameters was revealed. The results show that the seismic performance of the stiffening ring joint with stirrups was excellent, and stirrup confinement effectively improved the seismic performance of stiffening ring joints. Under a high axial compression ratio of 0.8, the joint with stirrup exhibited bending failure at the beam end, avoiding the phenomenon of column end bending failure in traditional specimens. In addition, the stiffening ring joint underwent a transition from beam energy dissipation to column energy dissipation when the beam-column flexural capacity ratio reached 1.39. The study's findings can serve as a guide for engineers using stirrups in square CFST column-steel beam joints with stiffening rings.

Experimental investigation on seismic performance of a super high-rise mega frame-double core tube composite structure

Increasing population density and urbanization have intensified the need for high-rise buildings in recent years. The seismic resistance of high-rise buildings should be carefully concerned in seismic regions, especially for super high-rise buildings which are most vulnerable to long-period earthquakes. This paper introduced the model design of a 499 m super high-rise mega frame-double core tube composite structure and presented the shaking table test results of the 1/50 scaled structural model. This super high-rise building possesses many conducive merits to resist seismic hazard, including steel reinforced concrete members, high-strength concrete and double core tube. In the test, there were three groups of long-period earthquakes and four incremental seismic intensity levels considered. The test phenomena indicated that the coupling beams of exterior tube were the first line of defense to resist seismic actions. The existence of inner tube improved the shear resistance of this building and there was no observed shear damage on the walls. Based on the instrumented data, the vibration characteristics, acceleration, displacement and strain responses of the structure were reported. The seismic performance of this super high-rise building meets the requirements of design specifications and its collapse resistance capacity is physically proved under severe earthquakes. However, the whiplash effect of acceleration is serious on the roof due to the reduction of mass and constraint for the mega column end. Furthermore, the inter-story drifts and strain responses of trusses in the top region are significantly larger. For the seismic measurement, great attentions should be paid to the exterior coupling beams and structural members in the top region of this super high-rise building. The presented work provides well experimental confirmation and reference for super high-rise buildings with mega frame-double core tube composite system.

Carbon Emission Analysis of RC Core Wall-Steel Frame Structures

The development of super high-rise building projects has become crucial for mitigating land shortages in rapidly growing urban areas. Super high-rise steel structures, particularly RC core wall-steel frame systems, have become the preferred choice due to their superior performance, high prefabrication level, and construction efficiency. Despite their benefits, super high-rise buildings face challenges related to higher energy consumption and carbon emissions. Consequently, it is important to analyze the carbon emissions of these buildings throughout their lifecycle and propose low-carbon construction strategies. A carbon emission analysis focused on super high-rise buildings with RC core wall-steel frame structures is conducted in this study. A carbon emission analysis model is constructed based on BIM-enabled LCA through a real-world case study. The emission factor method is combined with the BIM model to calculate carbon emission. Furthermore, carbon emissions across various construction strategies are compared, with a particular focus on the manufacturing processes of the main materials. The results indicate that incorporating admixtures in concrete, along with adopting the electric arc furnace (EAF) method and utilizing recycled scrap steel in steel manufacturing, significantly reduces the carbon emissions of the buildings. Lastly, effective low-carbon approaches for these buildings are proposed.

Comparative study of earthquake effects on the Canton Tower based on full-scale measurements

From 2011 to 2023, the monitoring system of a super high-rise structure, the Canton Tower, recorded many earthquakes. This study categorizes 11 earthquakes over these 13 years based on the distances between the epicenters and the tower for investigation. Firstly, the acceleration time histories and frequency spectra of these earthquakes are compared. Secondly, different system identification techniques, i.e., automated frequency domain decomposition (AFDD) and covariance-driven stochastic subspace identification (SSI-COV), are applied to the acceleration records to study the dynamic characteristics of the tower under earthquakes. Thirdly, three time-domain indexes based on the singular value decomposition (SVD) are proposed to measure and compare the impact of these earthquakes on the tower. The proposed indexes show good performance in assessing the impact of earthquakes and the structural condition. This study on the dynamic characteristics of Canton Tower under earthquakes at different distances can serve as a benchmark for further structural health monitoring and structural dynamic analysis.

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.

Analysis of Wind Load in a 15-Storey Building Using Various Lateral Load Resisting Techniques: A Review

Traditionally, outrigger and belt truss additions are used to strengthen the rigidity of tall buildings with central cores in order to control displacements. At the top of the structure, a single level outrigger can efficiently reinforce a building. The lateral stiffness of each outrigger level rises, although not as much as that of the top level. The primary lateral force-resisting elements of high-rise building structures are shear walls. Higher-performance shear walls are necessary because to the ever-increasing building code requirements and the rising height of high-rise and super high-rise structures. The conventional reinforced concrete shear wall is not very ductile, has a limited capacity to dissipate energy, and is not very deformable. Specifically, the base of a typical shear wall is particularly vulnerable to earthquake damage and is highly challenging to restore. In high-rise and super high-rise buildings, steel plate shear walls (SPSWs) and steel plate reinforced concrete composite shear walls (SPCSWs) are frequently used in place of regular reinforced concrete shear walls or shaped steel reinforced concrete composite shear walls to improve the seismic performance of building structures. Numerous structural methods seem to be able to withstand lateral stresses brought on by earthquakes, blasts, and wind. The more crucial it is to choose the optimal structural arrangement to counteract opposing horizontal loads. Keywords— High-rise structure, Outrigger, Shearwall, Damper etc.

Building Structural Design Innovation and Code Development

In recent years, Some new structural systems and design difficulties of high-rise and super high-rise buildings were emerged in Shenzhen, such as forced displacement and non-forced displacement, story lateral stiffness calculation method, frame-core wall structures with partial perimeter frame beams missing, super high-rise structure with great height-width ratio, high-rise less shear walls in one direction structure, conjoined tower structures, high-rise structure with inclined column, mega structure with belt truss, rare earthquake design method etc. The emergence and solution of these problems reflect the innovation of the structural design of high-rise buildings. Meanwhile, Structural design has encountered many difficulties and new problems. The solutions to these problems sometimes conflict with the current Chinese code, or there are no relevant provisions in the Chinese code. The current Chinese code is the basis for designing of high-rise buildings, which is the crystallization of the wisdom of previous generations, but the emergence of various new types of building structures has brought about numerous difficulties in structural design. Therefore, during the design process, it is necessary to conduct research, innovation, supplementation, and development of the current code. In view of this situation, this paper combines the previous engineering practical experience and introduces some structural design points of complex super high-rise buildings located in Shenzhen. It is for designers' reference, which also provides content for the revision of the specification.

Research on Key Problems and Optimization Based on Structural Design of Super High-rise Buildings

At present, complex super high-rise buildings and super high-rise buildings are emerging all over China, but there are still many problems to be solved in the design of super high-rise structures. For example, the wind pressure and earthquake risk of high-rise buildings, fire safety issues and personnel evacuation issues, earthquake will produce greater inertia force and bending force in high-rise buildings, wind load and wind pressure effect will be more significant, these are the parts that need to be carefully considered to ensure the safety and stability of the building structure. Therefore, it is necessary to analyze and optimize the problem of high-rise buildings. Taking a super high-rise building in Luohu District of Shenzhen City as an example, this paper analyzes the basic structure of super high-rise building, analyzes the key problems of structural design, and discusses the optimization method. This paper puts forward the optimization design method of building structure for seismic problem of super high-rise building structure, puts forward the solution to wind resistance problem, and puts forward the optimization layout method of building fire protection.

Shaking table test of vertical isolation performances of super high-rise structure under metro train-induced vibration

Metro systems are integral to improving transportation efficiency and providing convenience to the public; however, they cause environmental vibrations. To analyze the metro vibration propagation law and vibration isolation performance of a 120 m super high-rise structure positioned directly above two metro tunnels, a shaking table test at a 1/30 scale ratio is conducted in this study. First, a model for the shaking table test is designed and manufactured, and measurements of metro train-induced ground vibrations obtained on site are input into the model. Subsequently, vertical vibration tests are performed on the models with and without laminated rubber isolation bearings. Finally, their dynamic characteristics, vibration propagation law, and vibration isolation effect are analyzed, and the vertical vibration isolation mechanism of the structure is discussed. The results indicate that the metro vibration exerts a resonance effect on non-isolated super high-rise structures, thus resulting in the progressive amplification of the metro vibration response along the floors of the structure. The vibration isolation layer formed by the laminated rubber isolation bearings significantly reduces the vertical modal frequency and increases the vertical damping ratio of the super high-rise structure, thus effectively attenuating the vertical metro vibration. Unlike the non-isolated structure, the vibration-isolated structure can avoid severe structural resonance responses in the dominant frequency band of the metro vibration. This study aims to offer insightful considerations for evaluating metro vibrations in super high-rise structures and may serve as essential reference for vertical vibration isolation.

Mechanism study on the effect of floor rotation angle on supported tuned mass damper system of high-rise structure

The bending deformation of the super high-rise structures will cause floor rotation angle, and thus affect the vibration reduction effect of the supported tuned mass damper (TMD) system. This paper proposes a motion equation of the TMD control system with the effect of floor rotation angle. Firstly, a finite element model of the supported TMD control system was established by ETABS. Secondly, the formation and floor rotation angle parameters of the structure were obtained by ETABS modal analysis. Then, the structures ETABS model is simplified into a multi-degree-of-freedom (MDOF) model based on the dynamic characteristics of the structure. This paper also presents an evaluation index of the effect of floor rotation angle on the supported TMD system and a supported TMD control system is selected as a simulation example. The relationship between the floor rotation angle coefficient and the TMD parameters is later parametric analyzed. Finally, experiments were designed to verify the effect of floor rotation angle on the supported TMD control system. The experimental results show that the relationship between the rotation angle of the first formation floor and the generalized displacement of the first formation of the assumed structure is close to linear. Therefore, the effect of floor rotation angle of the structure is highly recommended to be considered as an important factor for the design of the supported TMD control system for super high-rise structures.

Creep and shrinkage monitoring and modelling of CFST columns in a super high-rise under-construction building

Concrete-filled steel tube (CFST) giant columns have been widely used in super high-rise structures. However, there is a major shortage of field measurements of shrinkage and creep deformation from actual projects. Existing experimental results and derived models cannot reflect the actual on-site conditions where sustained loading is an incremental process during construction and the facing environments vary. In this study, the deformations of giant CFST columns in a super-high-rise under-construction building were monitored for more than 400 d. For comparison, a scaled experiment was conducted in a laboratory. The strains measured in the laboratory and on-site show a good changing trend over time and could be used for model verification. The existing CEB-FIP (2010) model is improved in two ways: 1) introducing a reduction factor in the calculation of shrinkage strains and 2) considering the stress history and stress redistribution in the calculation of creep strains. With parameters determined from the experimental results, the modified model could predict the shrinkage and creep strains of CFST columns in the actual project well with sufficient accuracy.

Experimental study on seismic performance of super high-rise building with topology optimized diagonal mega frame

Diagrid system has received increasing attention by designers and researchers of high-rise building. In this paper, an innovative super high-rise diagonal mega frame-core tube structure adopting topology optimization for two-dimensional diagrid mesh and shape optimization for three-dimensional outline was introduced. Different from traditional diagrid structures, eight corner columns and a number of corner beams were used in the external diagrid frame, leading to unique spatial working capacity. In order to assess and study the seismic performance of this innovative structure, a series of shaking table tests on a 1/35 scaled model were conducted. Three earthquake waves and three seismic intensity levels were considered during the tests and the external diagrid frame tube showed strong lateral stiffness while severe tensile damage occurred at the bottom of corner columns under maximum considered earthquakes. Then repair work of the test model was initiated and second part of shake table test was conducted which covered the same loading steps of the first part test and more loading steps of two higher seismic levels. Based on a large amount of test data recorded, the acceleration response, displacement response, strain response, seismic fragility and hysteretic energy dissipation of this structure were analyzed. This structure performed satisfactory seismic performance and collapse resistance capacity without obvious whiplash effect and weak story. Corner columns became the key components due to their tremendous axial forces and welding connections of corner columns became the comparatively weak parts in this system, which need be carefully concerned in practical project.

Influence of outrigger truss system on the seismic fragility of super high-rise braced mega frame-core tube structure

The braced mega frame-core tube (BMFCT) structure is an efficient seismic structural system for super high-rise buildings of over 500 m high. The outrigger truss (OT) system has become a commonly adopted design option for the super high-rise BMFCT structure, however, its influence on the seismic performance is not clear. In this study, the seismic responses and collapse risks of the 590-m-high BMFCT structures with and without OT system were analyzed. An efficient elasto-plastic modeling method was introduced to establish the accurate FE models. Based on the incremental dynamic analysis-based (IDA) fragility analysis, the deformation responses, energy dissipations, collapse risks and collapse resistance capacities, etc. were researched. The results indicate the average top displacements under earthquakes of ‘one-degree-higher’ rare intensities are reduced by the OT from 1286.51 mm to 1348.31 mm by 4.6%. The OT system can effectively limit the story drift ratios of the BMFCT under earthquakes with the lower intensity. With the increasing seismic intensity, the OT presents an unfavorable effect on the lateral deformations. The OT system increases the proportion of damping energy dissipation from 68.28% to 70.24%, and decreases that of plastic deformation energy dissipation from 20.74% to 20.12%, both by less than 2%. The OT system causes the slope of IDA curves to rise first and then fall, which is the opposite of that without OT. The OT system is detrimental to the structural collapse resistance capacity, reducing the collapse margin ratio from 8.46 to 7.41 by about 14%. The OT's function can effectively reduce the cross-sectional dimensions of main components and ensure the architectural functionality and view-transparency. In the seismic design of BMFCT structures, the OT system should be given more attention, especially in the earthquakes stronger than rare intensity, and recommended to be designed to meet the basic structural stiffness requirement and not to provide excessive lateral stiffness resistance.

Deepening Design Technology of Super High-rise steel Structure

In view of the difficulties in deepening design of super-high-rise steel structures, we try to use Tekla Structures 3D intelligent steel structure simulation design software to carry out the corresponding deepening design, and verify the implementation effect of the deepening design with engineering practice, providing reference and reference for similar projects. The research shows that Tekla Structures is a very efficient and convenient software for steel structure deepening design; The connection nodes between giant columns and trusses should be divided in sections according to the principle of dividing along the section and along the column height, and reasonable lifting lug plates and studs for site use should be set; For hot-rolled steel plate composite floor slab, full-length reinforcing plates with the same thickness as the steel plate shall be set longitudinally on both sides of the splice weld of the adjacent unit steel plate; The thick plate welding shall be subject to process review in advance.

Principles and State-of-the-art Practice of Seismic Design of Modern Building Structures

Principles and state-of-the-art practice of seismic design of modern building structures is studied in this paper. At present, the earthquake damage can be simply divided into two parts: upper vibration and bottom instability. According to the currently widely accepted classification of earthquake damage, the vibration of the upper structure can be considered through the structural design, while the instability of the bottom such as faults, landslides and ground subsidence, etc. It is very important to then ensure the safety of the seismic performance of super high-rise structures. In the context of the new era, the scale of super high-rise building projects and the complexity of the structural system are gradually increasing. Hence, this paper gives the novel suggestions and proposes the solutions, the details have been discussed.

Investigation on seismic damping effect of an innovative amplified viscously damped outrigger for super high-rise structures

Investigation on seismic damping effect of an innovative amplified viscously damped outrigger for super high-rise structures

The innovative structural systems at the heart of China’s surge in super high-rise structures

There is a surge in the construction of super high-rise buildings in China. Bin Wang of Sichuan University outlines the various innovative structural systems being used, in particular the universal adoption of steel plate–reinforced concrete composite walls.

Seismic performance assessment of a super high-rise twin-tower structure connected with rotational friction negative stiffness damper and lead rubber bearing

In this paper, a novel rotational friction negative stiffness damper (RFNSD) composed of negative stiffness device (NSD) and rotational friction dampers (RFDs) is proposed to develop flexible connection for improving the seismic performance of an asymmetrical super high-rise twin-tower connected structure. The prototype structure is rigidly connected by long-span steel truss, and shaking table test has shown that the rigid connection between the towers and the truss corridor generally cause buckling of steel truss members and structural damage on the connected floors. To mitigate seismic responses of the truss corridor and the towers, the rigid connection is replaced by flexible ones using the proposed RFNSD and lead rubber bearing (LRB). The working principle of RFNSD is introduced and the theoretical force-displacement model is derived. The numerical model for the proposed flexible connection is presented and detailed three-dimensional finite element models for the rigidly and flexibly connected structures are established. Then by nonlinear time history analysis, seismic responses of the models under three-directional excitations are analyzed, and the effect of flexible connection’s design parameters is discussed. The results show that the developed flexible connection can obviously mitigate the dynamic responses and structural damages. As the stiffness of the pre-tensioned spring in NSD increase, the dynamic response of the steel truss connection corridor would be further decreased. The RFDs can effectively control the increased deformation of the flexible connection caused by the NSD, and promotes the energy dissipation capacity. The model with the flexible connections presents good seismic performance, indicating the effectiveness of the proposed RFNSD.

Research on Rust Removal and Rust Prevention Method of Super-High-Rise Steel Structure

The super high-rise steel structure is exposed to the natural environment for a long time, due to the long construction period of super high-rise buildings and the great impact of natural and social environment. If the steel structure is not properly protected, it will cause structural quality problems. Super high-rise steel structure has large volume and high height, so its rust prevention and rust removal methods are quite different from ordinary steel structure. This paper combines the actual engineering projects and briefly describes the ultra-high-rise steel structure rust removal, rust prevention construction and quality; safety assurance measures. Through the comprehensive application of this project, the feasibility of relevant countermeasures is confirmed, with a view to the follow-up similar projects can be useful and helpful.

Research on the Difficulties and Countermeasures of Super High-rise Steel Structure Construction

Steel structures are increasingly used in super high-rise buildings. The construction of super high-rise steel structure projects has many characteristics that are different from conventional steel structure construction. Combined with the actual engineering case, some of the key points, difficulties and countermeasures that may be encountered in the construction of super high-rise steel structure engineering are discussed, which is intended to provide referencefor future engineering.