Transfer Floor Research Articles

Behavior of difference types of transfer floors under seismic loads

Behavior of difference types of transfer floors under seismic loads

Seismic Analysis of High Rise Building with Transfer Floor

A transfer floor is the floor system which supports a vertical as well as lateral load resisting system and transfer its loading to different underneath system. Transfer floor distribute the load from closely spaced columns to the columns with long span. This study presented, a seismic analysis of high rise building with transfer floor. A number of proto type models of high rise building were analyzed using linear response spectrum analysis. The models were analyzed using structural software for building analysis ETABS 2016 software. The analyzed models has transfer slab system at different floor levels in high rise building. In this paper, five different models of 10 storey building had studied by providing a transfer slab at different floor levels such as first floor, second floor, third floor, fourth floor and fifth floor of the building. And the vertical position of transfer slab with respect to building height was investigated. The seismic response of high rise building such as storey shear, storey moment, storey displacement, inter-storey were numerically evaluated. Key Words: Transfer slab, Response spectrum analysis, Storey shear, Storey moment, ETABS 2016.

Progressive collapse performances of outrigger-braced reinforced concrete buildings with transfer floor

Progressive collapse performances of outrigger-braced reinforced concrete buildings with transfer floor

Study on the Influence of Transfer Floor on Dynamic Response of Building Structure under Subway-Induced Vibrations

In order to meet the functional requirements, it is often necessary to set the transfer floor in the high-rise building structure. From the perspective of the influence of transfer floor on the subway-induced vibration response characteristics of building structure, the finite element method is used to calculate the floor vibration response of the building with transfer floor under the excitation of subway train based on the actual project. Through the above analysis, the influence of the position of transfer floor on the subway-induced vibration response of the building is analyzed. The results show that the vibration level of the transfer floor roof decrease obviously when the position of the transfer floor moves up gradually, and the vibration levels of most other floors are increased to varying degrees. The third floor, that is the roof of the original transfer floor, has the most significant change in vibration.

The influence of different offset modes on the drainage characteristics of a double stack drainage system in a high-rise building

To meet the functional requirements of high-rise buildings, drainage stacks usually employ an offset pipe in the structural transfer floor. At the offset point, the flow direction changes and the air pressure fluctuates, which significantly influences the drainage system capacity and water seal effectiveness. Different offset modes have different degrees of influence on drainage characteristics. To better understand the influence of different offset modes on drainage characteristics, five different test conditions in double stack building drainage systems were established and investigated. DS1 was a standard double-stack drainage system with anti-reflux H-tube joints for every two floor levels. The remaining four systems were developed from DS1 by adopting various offset pipes (or pipe joints) on the fourth floor. DS2 adopted an S-shape offset pipe joint at the offset point. DS3 adopted double S-shape offset pipe joints. DS4 adopted a 1.0-m-long horizontal offset pipe. DS5 adopted a 1.5-m-long horizontal offset pipe. The pressure fluctuations and water seal losses were chosen as the experimental parameters to determine the maximum discharge capacity according to the Standard for Capacity Test of Vertical Pipe of the Domestic Residential Drainage System CJJ/T 245. The experimental results demonstrated that the installation of offset pipes (or pipe joints) contributed to the abrupt positive pressure and severe water seal losses at the position where flow direction shifted. As the length of the offset pipe increased, the positive pressure was more severe, and maximum discharge capacity was minor. The relationships among the maximum discharge rate, pressure fluctuation limits, and water seal losses are discussed. Lastly, a nondimensional analysis was adopted to understand the relationship between water seal losses and pressure limit values under different discharge rates for current test facilities. Practical application: Pipe offset has the potential to influence a drainage system discharge capacity. As the length of the horizontal offset pipe increases, the discharge capacity will decrease. In the actual design, the length of the offset pipe section should be reduced and this study demonstrates that the application of S-shape offset pipe joints is an efficient solution.

Computer-aided architectural design optimization based on BIM Technology

This article addresses the problem of the non-circulation of information in each stage of architectural design. This paper explores the architectural design process based on the BIM platform and puts forward the structural design method based on the BIM platform. It carries out the seismic analysis of a high-rise building with a transfer floor structure and compares the analysis results with the structural analysis software commonly used by the current design institute. The results obtained for experimentation show that the period ratio, displacement ratio, and the first six modes calculated by the two methods in the modal analysis are consistent. The error between calculation results and PKPM calculation results is within a reasonable range. In the analysis of the mode decomposition response spectrum method, the seismic forces in X and Y directions, floor shear, overturning moment, floor average displacement, and displacement angle obtained by the two models are compared respectively. The analysis results of the two methods accord with the mechanical characteristics of the transfer floor structure, and the calculation error is within the allowable range. The structural design based on the BIM platform has the advantages of high visualization, parameter-driven component size, and high model accuracy, improving design drawing efficiency.

Improving the Seismic Response of Tall Buildings: From Diagrid to Megastructures and Mega-Subcontrol Systems

Background: Diagrid structures, widely used for the tall buildings of the third millennium, are characterized by a very effective behaviour in the elastic field due to the grid triangulation. In particular, under horizontal actions, axial forces and deformations mainly arise in the structural members of the diagrid, thus resulting in the reduction of the shear lag effect and racking deformations. The response to incremental horizontal actions beyond the plastic threshold, however, shows a poor plastic redistribution capacity, with consequent low values of global ductility, in spite of a significant design overstrength. Objective: In this paper, it is proposed to exploit the high elastic efficiency of the diagrid type and use a vibration control system, based on mass damping mechanism with large mass ratios, to reduce a priori the inelastic demands due to seismic actions. Methods: Starting from the analysis of the seismic behavior of archetype diagrid buildings, a case study is selected to assess the effectiveness of the proposed motion-based design approach. For this purpose, the diagrid is first transformed into a megastructure (MS) configuration by densifying the diagonal elements at the most stressed corner areas and transfer floors, suitably chosen. Then, the exterior mega-frame is detached from interior sub-structures, thus allowing for a relative motion between the two structural portions according to a “mega-sub-structure control system” (MSCS), which activates the mass damping mechanism. Results: Time-history analyses carried out on simplified lumped-mass models confirm the effectiveness of the proposed strategy in reducing the seismic response. Conclusion: Finally, the practical feasibility of the MSCS and engineering solutions for the relevant structural organization are discussed.

Analysis of Construction Quality Control of Transfer Floor of High-rise Building

Analysis of Construction Quality Control of Transfer Floor of High-rise Building

Towards Seismic Performance of Tall Buildingswith Transfer Floors

Towards Seismic Performance of Tall Buildingswith Transfer Floors

Seismic Response Modification Factors for Buildings Featuring a Gravity Transfer System by Incremental Dynamic Analyses

ABSTRACT Tall buildings featuring transfer structures are commonly constructed in lower seismicity regions. Discontinuities in load paths of structural systems in the building were found to compromise ductility of the building. In a force-based seismic design procedure, response modification (R) factor is uncertain to cater for the undesirable features. This article presents a methodical approach for evaluating the seismic performance of such buildings. Results of incremental dynamic analyses of case study buildings indicated a high R-factor, due to the inherent over-strength. A local amplification factor (is recommended to account for localised shear at structural walls above the transfer floor level.

Research on the Construction Technology of Reinforced Concrete Beam Type Transfer Floor in High-rise Building

Research on the Construction Technology of Reinforced Concrete Beam Type Transfer Floor in High-rise Building

Mechanism of Transfer Story Beam-column in High-rise Buildings

The structural layout of the transfer floor is easy to cause the discontinuity of vertical components, Sudden change of floor lateral stiffness and floor shear capacity, they were unfavorable to the calculation of the overall index of the structure. In order to study the working mechanism of single span transfer beam on the first floor of high-rise building structure with or without interaction with wall, the mechanism of the beam and column was analyzed in the transfer layer of high-rise buildings, and the calculation methods of sectional moment for inertia beam and wall by using the calculation method of bending stiffness was put forward. A simple method for calculating the according to the different arrangement of the shear wall on the single-span transfer beam was deduced, the combined action of the transfer beam-shear wall and the non-combined action of the transfer beam-shear wall has been analyzed and calculated. The results show that, when the full span of the shear wall is arranged on the transfer beam and the deformation coordination is considered, the following conclusions are verified: the flexural rigidity of the transfer beam is suitable for the joint action of the beam and the shear wall of the upper layer ( 5 times amplification); Under the "arching effect", the transfer beam and the upper shear wall transform the vertical force into the horizontal support thrust, which increases the shear force of the frame pillar. It should be considered in the design. It can be used as a reference for engineering construction and design colleagues.

Fundamental study on rope vibration suppression by middle transfer floor using risk information

Lifts are essential for means of vertical transportation. Recently, the lifts installed in the high-rise buildings are long travel, thus the lift ropes are becoming longer. The natural period of the high-rise buildings is longer than that of the conventional buildings. In addition to the lift rope becomes longer, the natural period of the lift ropes become longer. Accordingly, the natural period of the lift ropes gets closer to the natural period of the building. Consequently, the lift ropes might be hooked to the equipment of wall when the lift ropes vibrate by an external force, such as a strong wind and earthquake. Furthermore, secondary accident such as containment of passengers and lift service stop may occur. In the Great East Japan Earthquake in 2011, 2015 cases of problem such as the catch and the damage of lift ropes have been reported. Operation of lifts after earthquakes are required for the security of the refuge course. Accordingly, the analytical method for comparative evaluation is investigated in this study. Furthermore, method to prevent a catch by vibration reduction of the lift ropes is investigated. In the previous research, it was confirmed that the division of the lift stroke is effective for reducing the response of the rope. When the lift stroke was equally divided. The displacement of the upper lift became larger than that of the other lift. Accordingly, the effectiveness of the division ratio of lift stroke was examined in this report. We investigated the catching of the lift rope using differential analysis and risk assessment. As the result, the displacement of the upper lift was decreased by the apposite division ratio. The probability of catching rope of the upper lift is reduced. Furthermore, it was confirmed that the risk of the catching rope reduces in probabilistic risk assessment.Lifts are essential for means of vertical transportation. Recently, the lifts installed in the high-rise buildings are long travel, thus the lift ropes are becoming longer. The natural period of the high-rise buildings is longer than that of the conventional buildings[1]. In addition to the lift rope becomes longer, the natural period of the lift ropes become longer. Accordingly, the natural period of the lift ropes gets closer to the natural period of the building. Consequently, the lift ropes might be hooked to the equipment of wall when the lift ropes vibrate by an external force, such as a strong wind and earthquake. Furthermore, secondary accident such as containment of passengers and lift service stop may occur. In the Great East Japan Earthquake in 2011, 2015 cases of problem such as the catch and the damage of lift ropes have been reported [2]. Operation of lifts after earthquakes are required for the security of the refuge course. Accordingly, the analytical method for comparative evaluation is investigated in this study. Furthermore, method to prevent a catch by vibration reduction of the lift ropes is investigated. In the previous research, it was confirmed that the division of the lift stroke is effective for reducing the response of the rope. When the lift stroke was equally divided. The displacement of the upper lift became larger than that of the other lift. Accordingly, the effectiveness of the division ratio of lift stroke was examined in this report. We investigated the catching of the lift rope using differential analysis and risk assessment. As the result, the displacement of the upper lift was decreased by the apposite division ratio. The probability of catching rope of the upper lift is reduced. Furthermore, it was confirmed that the risk of the catching rope reduces in probabilistic risk assessment.

Punching Shear Stress in Post-Tensioned Transfer Plate of Multi-Story Buildings

The design of a post-tensioned transfer plate is typically controlled by shear force—in particular, punching shear at the slab-column connection. To verify the accuracy of the separated model only for one floor currently used in the design of a post-tensioned transfer plate, results were compared to a complete model with multi-story building system for which two representative residential building plans were used to emulate physical structural systems. Punching shear stress for the separated model was calculated using the eccentric shear stress model presented in ACI 318. Punching shear stress was found to be overestimated in the separated model, given that interaction between transfer plates and upper shear walls cannot be reflected therein. Differences at column locations were also noted as the number of stories below the transfer floor increased. Consequently, the separated model is not recommended for design of post-tensioned transfer plates. A complete model is more suitable for more realistic and potential cost-effective design, through the inclusion of the interaction between transfer plates and upper shear walls.

Comparative Study of Regular and Irregular High-Rise Building with Transfer Floor using Dampers

Comparative Study of Regular and Irregular High-Rise Building with Transfer Floor using Dampers

A Review on High Rise Structure with Transfer Floor

As the population goes on increasing land requirement goes on increasing to resolve such issue transfer floor concept is best to provide the all the facilities and land requirement in one area to number of families. A floor system which supports load resisting system i.e. lateral as well as vertical load and loading is transferred to the different below system. The load is distributed from lower span of column to long span of column. A number of author’s publications is studied to get the brief knowledge about the transfer structure and the experiment done on it. The main objective of this paper review is to highlight the behavior of transfer structure under various seismic zones and which factors affect the structure.

Research on transfer floor technology in high-rise building construction

With the continuous improvement of the level of urbanization, people put forward higher requirements for the quality and safety of high-rise building projects. As an important part of high-rise building construction, the quality of transfer floor construction will directly affect the overall level of the construction industry. This paper mainly analyses and explores the general situation and technology application of the transfer floor of high-rise building structure. These applications improve the construction strength of concrete, steel bar and formwork; grasp the promotion of key links. Thus the overall construction reaches a higher standard, and the stability performance of high-rise buildings is improved.

Shaking table tests and numerical analysis of an over-track multi-tower building

This article aims to investigate the seismic performance of a four-tower (frame-shear wall) building with a large frame podium at bottom sitting on a metro depot through shaking table test and numerical simulations. Technical problems generally exist in this type of buildings due to irregularity in elevation and plan, tower offset, and structural transfer. These problems bring challenges to engineers when analysing and predicting dynamic responses under earthquakes which is crucial for structural safety. To evaluate the seismic performance of the building, a comprehensive study which includes a shake table test of the scaled model and time history analyses using a finite-element model is conducted. The shake table test model is designed based on the similitude law with a 1:40 scale. The dynamic characteristics, cracking pattern, failure mechanism, as well as maximum acceleration and deformation response are investigated. The corresponding finite-element analysis shows a good agreement with experimental results. It is concluded that this type of building can achieve the predefined performance objectives with well-behaved transfer floors. Shear failure at weak story is considered as a main failure mode of the structure. The whipping effect of stories on the top of structure is remarkable. There is no severe damage in steel reinforced concrete beams. Finally, some design suggestions are also proposed to improve the seismic performance of this type of buildings.

Post-fire Load-carrying Properties of a Reinforced Concrete Beam Supporting Column Transfer Structure Joint Unit

According to the characteristics of a reinforced concrete beam supporting column transfer structure, two types of full-size beam supporting column transfer structure joints are designed, and the post-fire residual mechanical behavior is tested. We observe the deformation and crack propagation of joint specimens under load, construct the load-deflection curve, record the post-fire residual strength and analyze the failure mode. The results show that longer exposure to high temperature is correlated with a smaller residual capacity of the joint units. When the specimens reach the ultimate bearing capacity, cracks form in the A-type joint unit specimens that are aligned with the central axis of the supported column, and several vertical cracks appear in the core area of the joint. The cracks of the B-type joint unit arise primarily on the compression side of the supported column, and many prominent inclined cracks arise in the core area of the joint that extend from the bottom to the compression zone of the transfer beam. Therefore, for structures with a bearing column girder transfer floor, the influence of the change of the internal force distribution on the post-fire load-bearing performance caused by the arrangement of the column should be considered.

Internal Force Analysis of Reinforced Concrete Structure with Bearing Column Girder Transfer Floor in Fire

Internal Force Analysis of Reinforced Concrete Structure with Bearing Column Girder Transfer Floor in Fire