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Construction noise is an integral part of urban social noise. Construction workers are more directly and significantly affected by construction noise. Therefore, the construction noise situation within construction sites, the acoustic environment experience of construction workers, and the impact of noise on them are highly worthy of attention. This research conducted a 7-month noise level (LAeq) measurement on a construction site of a reinforced concrete structure high-rise residential building in northern China. The noise conditions within the site in different spatial areas and temporal stages was analyzed. Binaural recording of 10 typical construction noises, including earthwork machinery, concrete machinery, and hand-held machinery, were performed. The physical acoustics and psychoacoustic characteristics were analyzed with the aid of a sound quality analysis software. A total of 133 construction workers performing 12 types of tasks were asked about their subjective evaluation of the typical noises and given a survey on their noise experience on the construction site. This was done to explore the acoustic environment on the construction site, the environmental experience of construction workers, the impact of noise on hearing and on-site communications, and the corresponding influencing factors. This research showed that the noise situation on construction sites is not optimistic, and the construction workers have been affected to varying degrees in terms of psychological experience, hearing ability, and on-site communications. Partial correlation analysis showed that the construction workers' perception of noise, their hearing, and their on-site communications were affected by the noise environment, which were correlated to varying degrees with the individual's post-specific noise, demand for on-site communications, and age, respectively. Correlation analysis and cluster analysis both showed that the annoyance caused by typical construction noise was correlated to its physical and psychoacoustic characteristics. To maintain the physical and mental health of construction workers, there is a need to improve on the fronts of site management, noise reduction, equipment and facility optimization, and occupational protection. [ABSTRACT FROM AUTHOR]

Muhe Bridge is China's first solid-web reinforced concrete arch high-speed railway bridge. This bridge is located in the hinterland of the Qinling Mountains, Shaanxi Province, where the terrain is complicated. The excavation of the south abutment foundation broke the local rock masses and caused a few unloaded joints. Composite pile foundation and anchor cables combined with shotcrete anchor technology were proposed to strengthen the foundation. The displacements of the foundation before and after the reinforcement were calculated and compared using the finite element method. A layer-by-layer construction scheme was adopted to construct the arch ring because its cross-section was too large. Finally, the additional forces and displacement of the rail tracks were investigated through bridge–track interaction analyses. The effects of long-term shrinkage and creep on the longitudinal stress and displacement of the rail tracks were revealed for different construction schemes. The results provide significant engineering experience for the construction of solid-web reinforced concrete arch bridges. [ABSTRACT FROM AUTHOR]

The main purpose of this study is to develop an estimation procedure of seismic design level setting for reinforced concrete (RC) piers considering aftershock-induced seismic hazards. This work develops an assessment method of the seismic hazards induced by aftershocks and takes an example of the Chi-Chi Earthquake in Taiwan. The number of aftershocks is assumed to follow the modified Gutenberg-Richter law with lower and upper bounds when analysing the cumulative density function of the magnitude of the aftershock within a specified post-mainshock period for the earthquake. Additionally, this work considers the spatial uncertainty in the hypocentres of aftershocks to assess the aftershock-induced seismic hazards. Fragility curves and residual factors of damaged RC piers are used in the transition probability matrix of Markov Chain model for considering the cumulative damage induced by aftershocks by incorporating uncertainty into aftershock events, as well as into structural capacity and residual factors corresponding to a specified damage state, the exceedance probabilities for various damage states can be estimated using Markov Chain model and Monte Carlo Simulation. Finally, in the case study, the proposed procedure is used to determine the important factor in the preliminary seismic design of typical RC piers for the Chi-Chi Earthquake in Taiwan. [ABSTRACT FROM AUTHOR]

Urbanization and real estate development are two mighty impetuses for the growth of China. An enhanced dynamic modeling has been devised to explore stocks and flows of buildings in the country and to quantify the related steel cycle. The uncertainties of the variables and results are investigated by the means of Monte Carlo method and sampling analysis. The building stocks are expected to increase to some 85–130 billion m 2 in the mid-century, about 40–100% up from the current level. Throughout China but in urban areas in particular, concrete structures are replacing the buildings made of wood, clay brick, and primitive materials. By 2050 every two out of three buildings in China will be reinforced concrete- or steel-framed, leading to substantial demand for ferrous metals. Scenarios analysis shows that a slowing down in the building stock expansion will likely occur in China in no more than ten years. This may open up a transition with profound industrial and resource implications. Increasing businesses for the construction industry may emerge from maintenance, retrofitting, and end-of-life management of existing buildings. The steel industry shall reform its capacity to conform to the growingly available secondary resources and the declining requirement for construction steel. Efficient and appropriate recycling of steel content from waste concrete will play an important role in material conservation. A collaboration of improvements in process material efficiency with lifetime extension and application of high-strength steel may save nearly 40% of primary iron ores for building use in the coming four decades. [ABSTRACT FROM AUTHOR]

A 15-storey K-braced reinforced concrete model frame with irregular columns, i.e., T-shaped, L-shaped, as well as +-shaped columns, was constructed and tested on the six-degree-of-freedom shaking table at the State Key Laboratory for Disaster Reduction in Civil Engineering in Tongji, China. Two types of earthquake records, El-Centro wave (south-north direction) and Shanghai artifi cial wave (SHAW) with various peak accelerations and principal-secondary sequences, were input and experimentally studied. Based on the shaking table tests and theoretical analysis, several observations can be made. The failure sequence of the model structure is brace→beam→column→joints, so that the design philosophy for several lines of defense has been achieved. Earthquake waves with different spectrums not only infl uence the magnitude and distribution of the earthquake force and the storey shear force, but also obviously affect the magnitude of the displacement response. The aftershock seismic response of previously damaged reinforced concrete braced frames with irregular columns possesses the equivalent elastic performance characteristic. Generally speaking, from the aspects of failure features and drift ratio, this type of reinforced concrete structure provides adequate earthquake resistance and can be promoted for use in China. [ABSTRACT FROM AUTHOR]

Many reinforced concrete or steel reinforced concrete single-tower buildings have been built in China. The structural performance of such one-tower structural systems depends on that of the primary components that are structural walls or moment-resistant frames. For multi-tower connected structures, problems become more complex. A multi-tower connected building, with large floor slab openings in plan and long-span truss in elevation, was thus studied because of its structural complexity and irregularity. First, a 1/25 scaled model structure was tested on the shake table under minor, moderate, and major earthquake levels. Then, the dynamic responses of the model structure were interpreted to those of the prototype structure according to the similitude laws. The experimental results were also compared with the numerical analysis of a three-dimensional finite element model for the irregular structure. Both experimental and analytical results demonstrate that, despite of the structural complexity, the overall responses of the building meet the requirements of the Chinese design code and the torsion of the structure is not remarkable. It is suggested that the strength and stiffness of the long-span connecting truss should be improved due to the potentially large vertical acceleration under strong earthquakes. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Field measurements of wind effects on the world's tallest reinforced concrete building (CITIC Plaza, 391 m high) located in Guangzhou were made during Typhoon Damrey in 2005. The field-measured data such as wind speed, wind direction and acceleration responses were simultaneously and continuously measured from the super-tall building during the typhoon. Detailed analysis of the field data was conducted to investigate the wind characteristics and wind-induced vibration of the high-rise structure. Based on the measured acceleration data, amplitude-dependent damping ratios of the building were estimated by the random decrement method. Dynamic characteristics obtained from the field measurements were compared with those calculated from the finite-element model of the structure. The serviceability of the tall building was then analysed based on the field measured results and design codes. Finally, a time-frequency analysis was carried out by the Hilbert-Huang technique to investigate the non-stationary features of the measured wind speed and acceleration response signals. The research output is expected to be of considerable interest and practical use to professionals and researchers involved in the design of super-tall buildings. [ABSTRACT FROM AUTHOR]

Investigation shows that concrete corrosion is a common problem for ocean reinforced concrete (R.C.) structures along China’s coast. A discussion of the corrosion characteristics, based on real project cases and field surveys, is presented in this paper. These factors that might affect corrosion, such as environmental effects, construction quality, cover thickness, property of the concrete material and structure type, are evaluated. Based on the analysis of these corrosion characteristics and affecting factors, the approaches available to improve the durability of ocean R.C. structures are proposed. [Copyright &y& Elsevier]