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Mass timber panels including cross-laminated timber (CLT), dowel-laminated timber (DLT), and nail-laminated timber (NLT) are used increasingly as floor slabs in mass timber buildings and hybrid timber buildings. The sound insulation performance of bare mass timber structural floors is insufficient due to their lightweight and relatively high bending stiffness. Floating concrete toppings are commonly applied for improved sound insulation performance with an elastic interlayer. The effect of different elastic interlayers and thickness of concrete toppings on improving the impact sound insulation performance was investigated experimentally according to ASTM standards in this study. The results showed that with the same elastic layer, thicker concrete toppings resulted in better impact sound insulation performance with a higher apparent impact insulation class (AIIC). However, by increasing the concrete thickness from 38 to 50 mm and to 70 mm, the improvement of AIIC between two thicknesses was only within 3, and a significant improvement up to 9 was observed with a 100-mm-thick concrete topping. In general, elastic interlayers with lower dynamic stiffness values performed better; however, the performance was product dependent though the apparent dynamic stiffness was measured using the same standard method. Moreover, with the same panel thickness and wood species, a bare DLT floor provided higher AIIC (35) than a bare CLT (21), but each mass timber floor with the same interlayer and floating concrete topping had the same impact sound attenuation performance. The ISO empirical prediction equation overestimated the impact sound attenuation of floating concrete toppings on mass timber floors. [ABSTRACT FROM AUTHOR]

Elastic materials can be used to improve the impact sound insulation performance of the floating floor. In this study, the foam rubber damping pad and polyurethane foam board were used to improve the sound insulation performance in floating floors; the main performance parameters such as thickness, dynamic stiffness, resonance frequency and damping ratio of the foam rubber damping pad and the polyurethane foam board were tested and analyzed under different loading systems. Besides, a reinforced concrete residential compartment was used as experimental background, the foam rubber damping pad and polyurethane foam board were used as elastic damping materials to form the different structures of floating floors with different thicknesses; then the impact sound pressure level and its variation rule were tested under different conditions, and the influence of the reduction of impact sound pressure level on the floating floor was compared and analyzed. The results show that before the pavement, the thickness of the polyurethane foam board is 2 times the thickness of the foam rubber damping pad in the natural state; After pavement, under the action of the load, the thickness of the polyurethane foam board is 1.39–1.42 times that of the foam rubber damping pad. The sound insulation and damping performance of the polyurethane foam board are lower than that of the foam rubber damping pad. When the thickness of the floating plate is increased from 32 to 80 mm, the sound insulation performance of the floating floor structure made of polyurethane foam board and foam rubber damping pad has a deterioration tendency. This study provides a basic reference for the sound insulation of floating floors with the foam rubber damping pad or polyurethane foam board as the elastic damping cushion. Highlights: Under load, the cumulative thickness of polyurethane foam plate reached about 35% of its total thickness at 2 days. After 8–10 days, it tended to be stable, with a total deformation of about 45%. For the floating building sound insulation floor system made of foam rubber damping pad, the frequency varies from 69.8–145.3 Hz, the reduction of impact sound pressure level is 18.7–23.6 dB, the change of frequency is 51%, and the reduction range of impact sound pressure level is 27%; The floating floor of polyurethane foam board has a frequency change of 137.7–254.8 Hz, the reduction of impact sound pressure level is 11.1–17.3 dB, the frequency change is 46%, and the reduction range of impact sound insulation is 35%. The thickness of the polyurethane foam board is about 1 times the thickness of the foam rubber damping pad, but its sound insulation and vibration absorption performance is low. It can be seen that the insulation board used as sound insulation board, its sound insulation and vibration reduction performance can not achieve the expected effect. [ABSTRACT FROM AUTHOR]

Summary: The present framework proposed the development of a Hybrid Rubber‐Concrete Isolation Slab System (HRCISS) to support building structures subjected to horizontal and vertical vibration due to ground motion and machine or equipment operation in the structure. Given that the effect of the shape factor on both horizontal and vertical stiffness has yet to be reported, the proposed composite system was comprised of two layers under the nodal points of the upper layer near the slab corners with four High Damping Rubber (HDR) components positioned between the slab layers to dissipate multidirectional (horizontal and vertical directions) vibrations. The ABAQUS software was utilized to model the finite element model (FEM) and simulate the HRCISS subjected to cyclic horizontal and vertical displacements. For the optimal HDR design, the model was applied in five 3‐story buildings, and the effect of distinct shape factors (0

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For the purpose of reducing the impact noise transmission across floating floors in residential buildings, two main sound transmission paths in the floating floor structure are considered: the stud path and the cavity path. The sound transmission of each path is analysed separately: the sound transmission through the cavity and the stud are predicted by statistical energy analysis (SEA). Then, the sound insulation prediction model of the floating floor is established. There is reasonable agreement between the theoretical prediction and measurement, and the results show that a resilient layer with low stiffness can attenuate the sound bridge effect, resulting in higher impact noise insulation. Then, the influences of the floor covering, the resilient layer and the floor plate on the impact sound insulation are investigated to achieve the optimised structure of the floating floor based on the sound insulation. [ABSTRACT FROM AUTHOR]

As a result of local factors, limited amounts of land and construction demands, subway lines are sometimes designed to run in close proximity to buildings. Hence, using a real Beijing subway engineering project, we have studied the vibration induced in a building by a moving rail vehicle. A numerical model of the spatially coupled vehicle–track–building system was developed to predict the vibration levels in the structure. The modeling theory was verified by comparison with multi-body system simulations and field test results. Two common types of track, namely, ballasted track and floating slab track were studied and their vibration-mitigation effects were compared in the time and frequency domains. A comparison of the particle peak velocities with the structural vibration limits of the floating floor slab and the first floor of a building revealed a very low possibility of severe damage resulting from vehicle-induced vibration for both types of tracks. We also conducted a one-third octave analysis of the vibration of each building floor and obtained the weighted root-mean-squared acceleration and vibration levels. A comparison of the weighted accelerations with the vibration limits for vibration perception by a human for both types of tracks also revealed that train-induced vibration had no obvious effect on daily human activities on most of the floors. The main exception to this observation was the first floor, which is located close to the vibration source. It is recommended that the first floor should be used for purposes other than residential. Furthermore, a comparison of the vibration levels of each floor for both types of tracks showed that the ballasted track had a better vibration-mitigation effect than the floating slab track for this special engineering case. [ABSTRACT FROM AUTHOR]

The aim of the research was to evaluate an influence of floating floor construction specimen size on weighted reduction in impact sound pressure level ΔLW. The large size (area ≥ 10 m²) specimens should be used according to LST EN ISO 10140 series standards. The problem is that produce large specimens is expensive and time-consuming process. So more rapid and cheaper way is to use smaller size (area < 10 m²) specimens and perform measurements in real buildings with similar test conditions as in laboratory. For evaluation of the specimen size influence on reduction in impact sound pressure level ΔLW value sand/cement screed area discreetly was reduced from 13.4 m² down to 0.5 m². The test results showed strong dependence of reduction in weighted impact sound pressure level from specimen size. Relying on the test data it was derived relationship which could be applied for the correction of the determined ΔLWvalues when smaller size specimens (area < 10 m²) of floating floor constructions are used. [ABSTRACT FROM AUTHOR]