scholarly journals Influence of the Acoustic Cover of the Modular Expansion Joint on the Acoustic Climate in the Bridge Structure Surroundings

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2842
Author(s):  
Janusz Bohatkiewicz ◽  
Michał Jukowski ◽  
Maciej Hałucha ◽  
Marcin Dębiński
Keyword(s):  
Sound Level ◽  
Structural Elements ◽  
Expansion Joint ◽  
Expansion Joints ◽  
The Road ◽  
Sound Levels ◽  
Road Surfaces ◽  
Before And After ◽  
Bridge Structures

The noise generated at the interface between the wheels of vehicles and the road surface is well recognized in the literature worldwide. Many publications describe the phenomenon of reducing this kind of impact by silent road surfaces. A specific type of this noise is the sound generated by vehicles passing over the expansion joints of bridge structures. Due to the impulsive nature of this sound, it is very onerous for people living in the close vicinity of bridge structures. The passage of vehicles over expansion joints causes the formation of vibrations that are transmitted to the structural elements of bridge structures, which may cause the formation of the material sounds (especially arduous in the case of bridges with steel elements). An attempt to reduce this impact was made by making a prototype acoustic cover of the expansion joint on the selected bridge. The paper presents the results of research on the “in situ” acoustic effectiveness of this cover. Additionally, the noise was modelled in the object surroundings before and after the cover’s application. The acoustic efficiency of the cover in the whole measured frequency range was 5.3 dBA. In the narrower frequency bands (1/3 octave bands), larger sound level reductions were observed. The maximum sound levels measured under the tested dilatation were less than 10.0 dBA lower than the maximum sound levels measured under the reference dilatation.

Experimental Study on Mix Ratio Design and Road Performance of Medium and Small Deformation Seamless Expansion Joints of Bridges

2021 ◽  
pp. 036119812098474
Author(s):  
Pengzhen Lu ◽  
Chenhao Zhou ◽  
Simin Huang ◽  
Yang Shen ◽  
Yilong Pan
Keyword(s):  
Traffic Safety ◽  
Performance Test ◽  
Asphalt Mixture ◽  
Small Deformation ◽  
Expansion Joint ◽  
Expansion Joints ◽  
Mixture Ratio ◽  
The Road ◽  
Marshall Test ◽  
Road Performance

Expansion joints are a weak and fragile part of bridge superstructure. The damage or failure of the expansion joint will lead to the decline of bridge durability and endanger the bridge structure and traffic safety. To improve the service life and performance of bridge expansion joints, the ideal method is to use seamless expansion joints. In this study, starting from the commonly used asphalt mixture gradation of seamless expansion joint, and taking into account the actual situation of bridge expansion joint structure and environment in China, the gradation and asphalt-aggregate ratio are preliminarily designed. Through a Marshall test, the corresponding asphalt mixture is evaluated and analyzed according to the stability, flow value, and void ratio, and the optimal gradation and asphalt-aggregate ratio are determined. Finally, the asphalt mixture is prepared with the mixture ratio design, and the test results of an immersion Marshall test, fatigue performance test, and full-scale test verify that the asphalt mixture meets the road performance requirements of seamless expansion joints. On the basis of the experimental data, the performance of large sample asphalt mixture is continuously tested, compared, and optimized. The results show that the asphalt mixture ratio designed is true and reliable, which can provide reference for the optimal design of seamless expansion joint filler.

Accuracy in the measurement of sound levels in situ with sound level meters

1975 ◽  
Vol 8 (1) ◽  
pp. 67-69 ◽  
Author(s):  
A. Behar ◽  
A. Domenech ◽  
R. Moncaglieri ◽  
M.A. Bustos ◽  
E. Dominguez
Keyword(s):  
Sound Level ◽  
Sound Levels

Evaluation of Bridge Project Variants from the LCC Perspective

2020 ◽  
Vol 47 ◽  
pp. 63-68
Author(s):  
Daniel Macek ◽  
Matouš Kosina
Keyword(s):  
Structural Design ◽  
Operating Costs ◽  
Structural Elements ◽  
Social Significance ◽  
Noise Barriers ◽  
Expansion Joints ◽  
Maintenance Costs ◽  
Software Application ◽  
Bridge Structures ◽  
Bearing Structure

The lowest purchase price is the easiest criterion in tendering for civil engineering. However, in view of the longevity of these buildings and their social significance, this criterion is insufficient. Renovation and maintenance costs play an important role in the construction life cycle and need to be taken into consideration, too. The structural design clearly influences the operating costs of the building, which can be predicted. The paper presents an example of how to approach this issue. The methodology is focused on bridge structures. The paper presents a software application for the calculation of renovation and maintenance costs which are generated from the following structural elements: abutments, pillars, deck (bearing structure), bearings, bridge deck insulation, drainage, roadway, cornice, railing, crash barriers, expansion joints and noise barriers. The structural elements can be specified in the application in predefined type / material variants. If the user uses material that is not included in the database, this situation is solved by adding the appropriate element to the database. If a combination of materials is used for one component, these materials are defined as separate structural elements. Bridge structures are evaluated over a lifetime of 100 years.

The effect of sound masking on employees' acoustic comfort and performance in open-plan offices in Canada

2021 ◽  
Vol 263 (1) ◽  
pp. 5678-5683
Author(s):  
Roderick Mackenzie ◽  
Joonhee Lee ◽  
Vincent Le Men ◽  
Farideh Zarei
Keyword(s):  
Work Performance ◽  
Signal To Noise Ratio ◽  
Sound Level ◽  
Sound Levels ◽  
Before And After ◽  
Acoustic Comfort ◽  
Sound Environment ◽  
Open Plan ◽  
Sound Masking ◽  
And Performance

Sound masking systems are commonly used in open-plan offices to generate a controlled minimum level of background sound, in order to decrease the signal-to-noise ratio of intrusive speech and blend out transient office noise. However, a question in the acoustical design of offices is whether the self-generated noise of occupants may alone be sufficient to provide the background sound level conditions necessary to achieve similar levels of speech privacy and acoustic comfort as sound masking systems. This study examines the relationship between occupant-perceived speech privacy and acoustic comfort under three different acoustic scenarios (no masking, controlled 42 dBA, and 47 dBA masking sound levels). The study was conducted pre-COVID-19 in two separate open-plan offices located in Quebec, Canada that at the time were close to full occupancy. Employees completed subjective questionnaires before and after each change in conditions, focusing on how the sound environment impacted their comfort and work performance during the study. Statistical results show that the occupants were significantly more satisfied during the two sound masking conditions in comparison to the no-masking condition, where only the occupant-generated and exterior/mechanical system noise was present as the background sound. Implications for open-plan offices with lower occupancy conditions post-COVID-19 are discussed.

scholarly journals Methods of on-site inspection of a reinforced concrete bridge exemplified by the bridge over the river Kosopasha

Vestnik MGSU ◽  
2020 ◽  
pp. 957-967
Author(s):  
Artem S. Piskun ◽  
Galina V. Ganets ◽  
Gleb A. Averchenko
Keyword(s):  
Reinforced Concrete ◽  
Leningrad Region ◽  
Shore Protection ◽  
Expansion Joints ◽  
Inspection Method ◽  
The Road ◽  
Reinforced Concrete Bridge ◽  
Bridge Abutment ◽  
Bridge Structures ◽  
On Site Inspection

Introduction. An on-site inspection method is a visual examination of an engineering structure aimed at the detection of defects, damages, and disturbances of a construction facility and further issuance of recommendations for their elimination. An on-site inspection method is among the principal ones applied, as it serves to identify all defects of bridge structures during their service lives. Materials and methods. The structures of the bridge over the Kosopasha river, located at the 5+910 km of the Pasha – Sviritsa – Zagubye motor road, the Volkhov District, Leningrad Region, were inspected. An on-site inspection method was applied to collect the information and perform the preliminary analysis. Results. The co-authors described the construction of the bridge elements, including the road deck topping, expansion joints, the safety parapet, sidewalks, hand rails, water insulation, the drain line, the bridge approach, the span, bridge support structures, piers, the bridge abutment, and the under-bridge area. They analyzed the condition of these elements at the time of their inspection; they compiled a report on defects, damages and the bridge deck capacity. The main defects include concrete leaching accompanied by concrete reinforcement denuding, concrete cracking and chipping, absence of safety parapet, partial destruction of rails, and failure of abutment strengthening constructions. Conclusions. Recommendations for the further operation of the bridge were formulated on the basis of inspection results. A set of measures is proposed with the purpose of eliminating the defects and further safe operation of the bridge structure. The recommendations include a set of repair works in respect of particular joints and constructions: removal of dust and dirt from the elements of the bridge topping and sidewalks, repair of minor damages of reinforced concrete structures, shore protection aimed at abutment reconstruction, installation of the safety parapet.

scholarly journals Predicting the Evenness of Road Surfaces

2021 ◽  
Vol 20 (3) ◽  
pp. 216-223
Author(s):  
Yu. V. Burtyl ◽  
M. G. Salodkaya ◽  
Ya. N. Kovalev
Keyword(s):  
Traffic Safety ◽  
Evaluation Criteria ◽  
Road Surface ◽  
The Road ◽  
Number Of Factors ◽  
Road Surfaces ◽  
Strength Based ◽  
On The Road ◽  
Comprehensive Indicator

The design of road surfaces involves application of  a sophisticated algorithm system based on mathematical calculations and engineering solutions, with the calculation of evaluation criteria.  It is precisely the observance of the standardized requirements in terms of design criteria that makes it possible to consider the design of the pavement as reliable, and the road as safe and convenient for traffic during the specified service life. When calculating the strength, based on the predicted traffic intensity and the composition of the traffic flow, calculations are carried out according to the main criteria: admissible elastic deflection, shear in layers of non-reinforced materials and in asphalt concrete, as well as the ultimate tensile stresses in cast-in-situ materials with the specified reliability level.  However, in the accepted concepts for  calculating the strength and reliability of road pavements,  only the force effect is directly taken into account. To take into account environmental factors, it is necessary to develop a comprehensive indicator of the resulting impact of all factors. The paper presents a complex of factors influencing on traffic safety, road deformations and irregularities the height of unevenness, in particular, an increase in the dynamic impact on the road and the amplitude of vibration of a car wheel on a road with an uneven surface (when detached from the road surface), the coincidence of the vibration frequency of the car with the natural frequencies of vibration of the road surface, and as a consequence, on the behavioral features of driving. The arguments have been substantiated that the predictive models do not take into account a number of factors that have a significant impact on the formation of irreversible deformation in the layers of materials of road structures.

Measurement and Analysis of the Structural Noise of Urban Bridges

2014 ◽  
Vol 548-549 ◽  
pp. 1623-1626
Author(s):  
Tao Jin ◽  
Qi Huang ◽  
Yong Ding ◽  
Li Feng Zhu
Keyword(s):  
Sound Pressure ◽  
Low Frequency ◽  
Measured Data ◽  
Sound Level ◽  
Frequency Noise ◽  
Acoustic Environment ◽  
The Road ◽  
Sound Levels ◽  
Measurement And Analysis ◽  
The City

To explore the noise generated by bridges during operational period, the equivalent continuous sound pressure levels of 12 bridges in the city of Ningbo were measured and analyzed. The measured data show that (1) Although the measured sound levels of these bridges meet the requirement of Chinese codes, they are near the maximum limit and the vibration and noise reduction is necessary; (2) A-weighted sound level of bridge is close to that of the road nearby; (3) Z-weighted sound level of bridge is much greater than that of the road nearby, it indicates that the bridge noise contains much low frequency noise, so that A-weighted sound level can’t reflect the noise of bridge accurately, and Z-weighted sound level shall be used to evaluate the acoustic environment near bridges.

Optimization of Noise and Vibration of a Cylindrical Cam Mechanism Using Inertial Compensation Techniques

1997 ◽  
Author(s):  
Song Lin Ge ◽  
Giovanni Nerli ◽  
Monica Carfagni
Keyword(s):  
Considerable Effect ◽  
Sound Level ◽  
Noise And Vibration ◽  
Remarkable Effect ◽  
Cam Mechanism ◽  
Compensation Systems ◽  
Sound Levels ◽  
Before And After ◽  
The Difference ◽  
The Impact

Abstract An innovative concept has been developed in which the dynamic behaviour of a cylindrical cam mechanism is modified using inertial compensation techniques. Elastic and magnetic compensation systems are incorporated in the experimental acoustic and acceleration analysis procedure. Both compensation systems have a remarkable effect on the reduction of the noise and vibration levels produced by the impact between the cam follower and the groove inversions. However, individually they both have different influences on the groove junctions. Generally they both have a considerable effect on the integral cam mechanism in terms of reducing emitted sound levels. The results also show that the difference in emitted sound levels before and after modification is approximately 3 dB. This conclusion means that the difference of the equivalent sound level is roughly equal to a reduction of about thirty percent below the original level with the compensation devices in position.

Comparison of In Situ and Laboratory Testing for the Characterization of Old Timber Beams before and after Intervention

2010 ◽  
Vol 133-134 ◽  
pp. 1101-1106 ◽  
Author(s):  
Maurizio Piazza ◽  
Mariapaola Riggio ◽  
Roberto Tomasi ◽  
Ivan Giongo
Keyword(s):  
Laboratory Testing ◽  
Mechanical Characterization ◽  
Testing Procedure ◽  
Structural Elements ◽  
Bending Tests ◽  
Before And After ◽  
Strengthening Technique ◽  
And Control

In this paper an investigation campaign, carried out in occasion of the restoration of a timber floor in the Belasi Castle (Trentino, Italy), is reported. In order to validate a testing procedure for the calibration and control of an innovative wood-wood strengthening technique, results of tests performed in situ on the structural elements, in both the original and the repaired condition, have been compared with those obtained in laboratory on some dismantled beams. For the characterization of the material decay, both local mechanical and global vibrational testing have been carried out. For the mechanical characterization of the beams, before and after repair, direct static bending tests have been performed, with distributed loads, on site, and according to standard four-points loading schemes, in laboratory.

Equivalent sound level as a predictor for road traffic noise annoyance assessment

2021 ◽  
Vol 263 (2) ◽  
pp. 4622-4633
Author(s):  
Jan Felcyn ◽  
Anna Preis
Keyword(s):  
Road Traffic ◽  
Traffic Noise ◽  
Calculated Data ◽  
Sound Level ◽  
Time Structure ◽  
Single Type ◽  
Road Traffic Noise ◽  
The Road ◽  
Noise Annoyance ◽  
Sound Levels

Noise annoyance can be rated either in situ or in laboratory conditions. Regarding the , many papers indicate that only 30% of the variance in people's answers can be explained by sound level values. This value increases when a single type of noise is presented to participants in lab. However, the relationship between time structure of the noise stimulus and annoyance rating is still ambiguous. In this study road traffic noise stimuli with different time structure at three different sound levels were created. Moreover, the psychoacoustical characteristics of them were also computed. The calculated data was compared with results of the listening test in which participants rated each stimulus on the numerical ICBEN scale. Analysis showed that loudness and sound level are the dominant factors, they correlate quite well (~70%) with people's ratings. However, the different time structure of the road traffic noise at the same sound level did not evoke significantly different noise annoyance ratings. Since there are no standards available for loudness measurement, the sound level for the same type of noise remains the simplest factor to reliably predict its impact on people regarding noise annoyance.

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