Slab Vibration Research Articles

Slab Vibration and Horizontal–Vertical Coupling in the Seismic Response of Low-rise Irregular Base-isolated and Conventional Buildings

ABSTRACTThis paper evaluates factors that may influence slab vibration and/or induce a horizontal–vertical (H-V) coupled response of buildings with mass irregularities. Responses are investigated through computational simulation of a hypothetical three-story building with base isolation and conventionally configured. Induced mass eccentricities are observed to influence, in an unpredictable way, the vertical slab acceleration and the H-V coupled response, which is identified through modal analysis and floor spectral analysis. The implications of vertical slab vibrations and H-V coupling behavior on the design forces for nonstructural components and systems (NCSs) are evaluated, and modifications are proposed for consideration.

Computational simulation of slab vibration and horizontal‐vertical coupling in a full‐scale test bed subjected to 3D shaking at E‐Defense

SummaryThis paper focuses on slab vibration and a horizontal‐vertical coupling effect observed in a full‐scale 5‐story moment frame test bed building in 2 configurations: isolated with a hybrid combination of lead‐rubber bearings and cross‐linear (rolling) bearings, and fixed at the base. Median peak slab vibrations were amplified—relative to the peak vertical shake table accelerations—by factors ranging from 2 at the second floor to 7 at the roof, and horizontal floor accelerations were significantly amplified during 3D (combined horizontal and vertical) motions compared with 2D (horizontal only) motions of comparable input intensity. The experimentally observed slab accelerations and the horizontal‐vertical coupling effect were simulated through a 3D model of the specimen using standard software and modeling assumptions. The floor system was modeled with frame elements for beams/girders and shell elements for floor slabs; the insertion point method with end joint offsets was used to represent the floor system composite behavior, and floor mass was finely distributed through element discretization. The coupling behavior was partially attributed to the asymmetry of the building that was intensified by asymmetrically configured supplemental mass at the roof. Horizontal‐vertical coupled modes were identified through modal analysis and verified with evaluation of floor spectral peaks.

에너지 수확장치 기반의 무선 층간진동 알람 시스템 연구

The disputes due to floor noise in apartments have become a major social problem over the past few years. Unlike with high-cost and long-term solutions such as developing new noise attenuation techniques and tightening up the construction-related legislation, a method of conflict mediation among residents can be a cost-effective and immediately applicable solution. Since the floor vibration alarm system can support the mediation process by providing objective data on human-induced floor vibration; in this study, a study on the self-powered wireless system for floor vibration alarm was performed. The vibration-based piezoelectric energy harvester was first fabricated based on the vibration level measured on the bare slab, which is installed on the top of the reverberation room. Through excitation tests using an impact ball and a bang machine, the correlation among harvested electric energy from the energy harvester, slab vibration and sound pressure level measured in reverberation room was analyzed. The test results show that they are highly correlated at the design frequency. The prototype of the wireless floor vibration alarm system utilizing the energy harvester was manufactured and the feasibility was checked and demonstrated.

Free vibrations of precast modular steel-concrete composite railway track slabs

This paper highlights a study undertaken on the free vibration of a precast steel-concrete composite slab panel for track support. The steel-concrete composite slab track is an evolvement from the slab track, a form of ballastless track which is becoming increasingly attractive to asset owners as they seek to reduce lifecycle costs and deal with increasing rail traffic speeds. The slender nature of the slab panel due to its reduced depth of construction makes it susceptible to vibration problems. The aim of the study is driven by the need to address the limited research available to date on the dynamic behaviour of steel-concrete composite slab panels for track support. Free vibration analysis of the track slab has been carried out using ABAQUS. Both eigenfrequencies and eigenmodes have been extracted using the Lanczos method. The fundamental natural frequencies of the slab panel have been identified together with corresponding mode shapes. To investigate the sensitivity of the natural frequencies and mode shapes, parametric studies have been established, considering concrete strength and mass and steel

Seismic Simulation of an Integrated Ceiling-Partition Wall-Piping System at E-Defense. I: Three-Dimensional Structural Response and Base Isolation

AbstractThe seismic response of a full-scale, 5-story steel moment frame building in base-isolated and fixed-base configurations with an integrated suspended ceiling-partition wall-sprinkler piping system that was shaken at E-Defense is critically assessed. Horizontal floor accelerations were constrained by the isolation systems to relatively low levels, which allowed observation of damage to the integrated system that was directly related to the vertical component of input acceleration. The floor slabs exhibited single mode vibration at their natural periods with widely varying effective damping. Peak vertical accelerations were amplified by an average factor ranging from 3 to 6 from the table to the middle of the floor slabs, at which amplification factors increased as slab vibration periods lengthened. Damage to the ceiling-partion-piping components initiated at slab accelerations of approximately 2 g and became extensive for slab accelerations exceeding 5 g. These metrics establish target vertical acc...

Accurate periodic solution for nonlinear vibration of thick circular sector slab

In this paper we consider a periodic solution for nonlinear free vibration of conservative systems for thick circular sector slabs. In Energy Balance Method (EBM) contrary to the conventional methods, only one iteration leads to high accuracy of the solutions. The excellent agreement of the approximate frequencies and periodic solutions with the exact ones could be established. Some patterns are given to illustrate the effectiveness and convenience of the methodology. Comparing with numerical solutions shows that the energy balance method can converge to the numerical solutions very rapidly which are valid for a wide range of vibration amplitudes as indicated in this paper.

Study of the Effect of Cement Asphalt Mortar Disease on Mechanical Properties of CRTS II Slab Ballastless Track

This paper built the three dimension mechanics model of CRTSII slab ballastless track structure on subgrade with ANSYS software. Analysis the influence of deformation and stress characteristics caused by different temperature gradients and the coupling action of temperature gradients and train loads under different work conditions, including no-separated, separated, and multiple-slabs separated with the cement asphalt mortar layer. The results show that, temperature gradients on track slab is one of the main reasons which caused the gap appearing between the bottom of slab track and cement asphalt mortar elastic cushion. And the joint main cause the deterioration of vibration of track slab, accelerating the deterioration of the cement asphalt mortar layer.

Vibration response of cement structures under conditions of impact loads

Abstract A flexible function layer between concrete base and pavement slab is constructed to avoid slab breakdowns caused by poor vibration damping and energy absorption of cement structures. Practical experiments as well as testing and analyzing systems are employed to collect the frequency signals from the pavement structure vibration for a small pavement slab structure subjected to a ball-drop impact. The results reveal that the vibration can be damped out and energy can be absorbed using such a flexible function layer. Based on the contrastive tests, the pavement slab vibration is a declining process under the impact load. The vibration damping effect is more significant with the increase in thickness of the function layer, but becomes slower if the layer reaches a certain thickness. The tests also show that the flexible function layer has a significant role in the vibration damping and energy absorption.

Numerical Simulation and Parameter Analysis of Building Vibration Caused by Ground Line of Rail Transit

Having the entrance/exit depot line of Guogongzhuang metro depot of Beijing metro line 9 as the background, ballasted track-soil model is established and simulated. The accuracy of the model is proved comparatively high. Taking the nearby building as the research object, effects of structure characteristics modification of the building on slab vibration are discussed. The results suggest that: The trend of the vibration levels of slabs changing with the floors is the same as that of the benchmark example after changing the structure characteristics of the building. As the dimension of columns increases and the performance of the concrete is better, the vibration levels of the building decrease obviously. As the thickness of slabs increases, the effect is much more complicated. The vibration level of each slab increases from basement 2 to the 14th floor by 0.02 to 8.4dB. The vibration level of each slab decreases from the 15th floor to the top floor, and the vibration levels are 0.8 to 9.9dB lower than that of the benchmark example.

Weakened Support Detection Based on Road Slab Vibration Response

This paper presents a vibration testing method to monitor the deterioration and weakened support on slabs of cement concrete pavement. After discussing on methods for void evaluation, a dynamic finite element model of road slab with Winkler foundation assume is established according to the structure of slabs both in good condition and conditions with varying degrees’ defects, and computer simulation to vibration characteristic is conducted and a corresponding measuring system is proposed. Its results can be used to guide actual test.

Study for the Dynamic Response of Rubber Concrete RC Slab

The tradition RC building slab system is very rigid so the vibration and the will induce large noise often creates puzzle of the user. The slab vibration also will reduce the production fine proportion for high tech factory. So we must to enhance the RC slab energy absorbing capacity to reduce RC floor vibration. The rubber material has very good elasticity and energy absorbing capacity so is widely applied in many daily items. But the easy consuming characteristic will increase the waste process problem. If we can apply the high elasticity property in recycle rubber to RC slab so we can reduce the waste pollution and slab vibration behavior in the same time. The complex RC slab real behavior must be measure from test result. In this paper we want to get the dynamic behavior by pedestrian loading for rubber concrete RC slab by laboratory test. By the test results we can found the 5% rubber concrete will concentration to 7.2 Hz.

Control of floor vibration and noise using multiple tuned mass dampers

The floor impact noise that occurs between upper and lower households in residential houses has been known as one of major causes that adversely affects residential environments and can lead to serious social troubles in a residential community. In order to alleviate this problem of floor impact noise and to improve the residential conditions, regulations are applied in many countries to reduce the floor impact noise. The floor impact noise can be divided into two categories - light weight floor impact noise and heavy weight floor impact noise - depending on the standard impact sources and the frequency range where the noise is dominant. The light weight floor impact noise generated in the high frequency ranges can be easily reduced by resilient material used in a conventional floating slab system, whereas the heavy weight floor impact noise induced by flexural vibration modes in the relatively lower frequency ranges is difficult to reduce using the traditional methodologies such as a floating slab system or increasing the thickness of slab. In this study, a new method is presented to effectively reduce the heavy weight floor impact noise induced by the vibration of slab using the multi tuned mass dampers (MTMDs). A substructure modal synthesis technique based on the FEM model is utilized to develop an analytical model of the slab coupled with MTMDs. Further, the acoustic power and acceleration responses are analyzed to evaluate the performance of the MTMDs in reducing floor impact noise. Numerical analysis is carried out to investigate the effect of the MTMD on the vibration and noise control of the simply supported slab

A STUDY ON PREDICTION OF HEAVY WEIGHT FLOOR IMPACT SOUND LEVEL BY FINITE ELEMENT METHOD

In this paper, we study the predicted floor impact sound level by finite element method. At first, we study the influence of the partition on the slab vibration in addition to the impedance characteristic of the partition.Following this, the influence on the slab vibration characteristic is shown by the construction of the partition.In addition, it is shown that the model employed in this experiment is more effective than the board unit based on the impedance characteristic of the partition.Finally, the difference between the partition groundwork specification and the space size forces the examination of the influence on the vibration characteristic and the space sound pressure.Following this, it is shown that the influence of the sound radiation of the partition is minimal in the evaluation frequency of the floor impact sound insulation.

EXPERIMENTAL STUDY ON VERTICAL VIBRATION CONTROL BY A TMD USING A ROTATING INERTIA MASS

A tuned mass damper (TMD) using a rotational inertia mass has been developed to reduce vertical vibrations of beams and slabs subjected to walking excitations and earthquake motions. The newly developed TMD is composed of a spring and a ball screw mechanism with a fly wheel. Vibration tests of a beam structure were carried out to show the effectiveness of the TMD using a rotational inertia mass and compare the test results with those of simulation analyses using a theoretical model.

VIBRATION CONTROL BY A TMD USING A ROTATING INERTIA MASS

A tuned mass damper (TMD) using a rotational inertia mass has been developed to reduce vertical vibrations of beams and slabs subjected to walking excitations. The newly developed TMD is composed of a spring and a ball screw mechanism with a fly wheel. Vibration tests of a beam structure were carried out to show the effectiveness of the TMD using a rotational inertia mass and compare the test results with those of simulation analyses using a theoretical model.

다중동조질량감쇠기를 이용한 단순지지 슬래브의 진동 및 소음저감에 관한 연구

In this study, it is outlined that heavy weight floor impact noise induced by the vibration of slab can be reduced using multi tuned mass damper(MTMD) effectively. Substructure synthesis is utilized to develope analytical model of the slab coupled with MTMD and acoustic power is introduced to evaluate the performance of noise control for simplicity. Numerical analysis is carried out to investigate the effect of the properties of MTMD on the vibration and noise control of the simply supported slab. Numerical analysis shows that mass ratio of MTMD is critical on the vibration and noise control of the slab and it is also essential to reduce the vibration in higher modes of slab in the light of its great effect on the radiation of sound.

연구소(硏究所) 건물(建物)의 슬래브 진동(振動) 성능개선(性能改善) 연구(硏究)

A vibration in the building occurs by influences of the facility equipment and the structural system. As the building recently becomes higher and bigger, the vibration in the floor slab is issued. Specially, the vibration with <TEX>$4{\sim}8Hz$</TEX> frequency is harder to control than any other range of frequency. This vibration easily affects human sensibility and often makes the resonance phenomenon by corresponding with the floor slab's natural frequency when people and heavy equipments move. Moreover, the permission regulations for the vibration of the building are established by building's purposes. However, it is not subdivided in detail and sometimes ambiguous to each client. Even though the vibration could cause negative influences in a research building, there is not the vibration criterion for a research building. Therefore, it is necessary to set up its own vibration criterion with the client before building and to keep checking this vibration criterion under the construction. This study proposes the reasonable control methods and the vibration criterion for floor slab's vibration which are adapted to the R4-project. The R4-project is a research building and a high-rise building also. Accordingly, this study could help to the next similar project in the design and the construction phase.

Vibration of a room-sized airspring-supported slab

Vibration of a room-sized airspring-supported slab

Prediction of heavy weight impact sound of large-spanned slabs

Adaptation of the large-spanned RC slabs, whose area corresponds to an apartment unit, is increasing in Japan. The authors measured heavy-weight impact sound and impedance of such large slabs at over 30 sites. The structural methods of slabs are: unbond, half-precast concrete, void, and the conventional framework method. There were no distinctive differences among structural methods except in case for void slabs. The impact sound level was determined by the thickness of the slab rather than the area of the slab, even if the area of the slab was over 70 m2. In the case of small slabs, where the first eigenfrequency of the slab vibration is around the 63-Hz octave band, there is a tendency of a high-impact sound level. On the other hand, the lower first eigenfrequency may be a benefit for the impact sound level. The stiffness level of the beam seem to depend on frequency.

Vibrations of slabs and cylindrical nuclei

We study shape vibrations of slabs and cylindrical nuclei, recently proposed as possible nuclear shapes in the deep inner crust of a neutron star. Bosonic specific heats are calculated accordingly. At low temperatures they are found to be negligible compared to the fermionic contributions, while at temperatures typical of a very young neutron star, the bosonic specific heats are found to be important.