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This paper mainly demonstrates some experiences in China regarding surface damage inspection and performance evaluation of reinforced concrete (RC) bridges. To begin with, the mechanisms of the major damages of RC bridges such as chloride attack, concrete carbonation, and rebar corrosion are briefly reviewed. A statistical result of concrete cracking that exists in (prestressed) concrete bridges is presented as well. Second, the inspection practices of surface damages such as crack by using computer vision and deep learning on the RC pylons of the Jiang‐Yin Yangtze River bridge are demonstrated. Third, the specifications used in China for the performance evaluation of RC bridges are introduced. Its general philosophy and framework are explained. The Xia‐Men bridge is taken as an example to illustrate how to conduct a quantitative performance evaluation by following the instructions in China specifications. Finally, some perspectives on more advanced and efficient inspection techniques and performance evaluation methods are provided. [ABSTRACT FROM AUTHOR]

The steam curing technology is worldwide applied in the production of concrete prefabricated components, including the production of track slab and girder used for the high‐speed railway in China. However, the steam curing process at elevated temperature will often generate the heat damage on concrete and thus degrade the long‐term performance of the steam‐cured concrete prefabricated components. It is very important to deeply understand the mechanism of heat damage and thus to find effective method reducing or avoiding the damage of steam curing on concrete. The main purpose of this paper is to systematically classify the types of thermal damages on concrete during the steam curing and its mechanism. The influences of main factors on three thermal damages such as the unrecoverable expansion deformation, the surface layer defect, and the embrittlement of the steam‐cured concrete are discussed in detail. The controlling methods of thermal damages including optimization of the steam curing regime and mixing proportions, the addition of supplementary additives, the self‐healing technology, and other curing technology are compared and summarized based on the literatures. Finally, suggestions for future research are proposed in order to effectively reduce or even avoid the thermal damage of the steam‐cured concrete. And also, some new technology for developing the green and high performance early strength concrete with low CO2 emission are presented. [ABSTRACT FROM AUTHOR]

A new structure named reinforced concrete grid moment‐resisting frame (RC‐GMRF) have been adopted in high‐rise buildings in China. However, complex construction due to numerous beam‐column joints restricts the application of this structure. A novel precast reinforced concrete GMRF (PC‐GMRF) is proposed in this paper to solve this problem. Three specimens, including one traditional reinforced concrete moment‐resisting frame (RC‐MRF) as reference, were tested under reverse cyclic loading to evaluate the seismic performance. All three specimens were designed using the same amount of construction material. The experimental results showed that PC‐GMRF exhibited comparable seismic performance with that of RC‐GMRF. The load‐carrying capacity, initial stiffness and energy dissipation capacity were improved by an average of 43%, 29%, and 21%, respectively, compared with those of RC‐MRF. This study indicated that the performance of PC‐GMRF was acceptable and could be used in the moment‐resisting frame as a novel structure. [ABSTRACT FROM AUTHOR]

MgO‐based expansive additive (MEA) is uniquely used in China to compensate for the thermal shrinkage. For mass concrete, its inner temperature can soar up to 60°C due to the accumulation of hydration heat, which will strongly impact the mechanical properties and microstructures. In this paper, the impacts of elevated curing temperatures on the compressive strength developments, the tensile strengths as well as the pore structures of MEA cement mortars are investigated by means of X‐ray diffraction, scanning electron microscope, and mercury intrusion porosimetry. The results show that the external addition of MEA weakens, not eliminates, the crossover effect found in the temperature‐affected strength developments, which is mainly attributed to the accelerated expansion of MEA. For the tensile strength, the weakness of the crossover effect is found more obvious. The ratio of tensile to compressive strength is also positively correlated to the MEA content and the curing temperature. A scattered prestress effect is proposed to explain this phenomenon. The microcosmic evidence proves that the elevated temperature promotes the hydration of MEA and cement, and thereby improves the early‐age microstructures but impairs the late‐age one, which is generally consistent with the mechanical results. [ABSTRACT FROM AUTHOR]

Precast concrete structure has been increasingly used all over the world. Its seismic performance has always been the key factor of its application in earthquake‐affected zones, especially in China. A new precast concrete shear wall structure using grouted lap splice connection and cast‐in‐place concrete was proposed in this paper. Low‐cyclic reversed load testing was conducted on a one‐half scale spatial specimen of the bottom four stories of the new precast concrete shear wall structure. The test results were compared with the push‐over analysis results to evaluate the seismic performance of the specimen. The specimen showed good integrity and satisfies the current demands for Chinese seismic fortification. Moreover, due to the effect of infill walls strengthening the shear walls, and the effect of local cast‐in‐situ concrete regions constraining the precast components and connecting transverse walls to longitudinal walls, the specimen performed as tube structure and possessed excessive strength and stiffness. [ABSTRACT FROM AUTHOR]

Vertical and differential deformations in super-high-rise buildings are extremely important during construction. In order to be able to adjust the construction process accurately, taking the deformations into account, such deformations must be calculated exactly. The analysis of the vertical deformations of the high-rise Shanghai World Financial Centre building is illustrated in this paper. The prediction models of CEB-FIP 90 are used for calculating shrinkage and creep. The fictitious degree of hydration method has been applied for calculating the creep behaviour of the early-age concrete. The influence of steel bars on the vertical deformations has been analysed based on the macroscopical modulus method. Calculation of the vertical deformations includes the pre-construction and the post-construction deformations. Finally, the differential deformation between the concrete and the mega-structure column is determined. Theoretical results for the vertical displacement of this super-high-rise building agree very well with field monitoring data. [ABSTRACT FROM AUTHOR]

One of the most challenging aspects in the construction of Stonecutters Bridge, Hong Kong, was the erection of the concrete backspan structures. At a height of about 70 m a geometrically complex grillage deck was to be constructed. The superstructure cannot support its own weight before the stay cables are installed; it was thus constructed on a unique falsework system required until stressing of the stays. The paper describes the development of the construction procedures, the construction engineering and the design of the temporary works. The work involved the accurate stage-by-stage modelling of the entire construction process to assess the structural adequacy throughout and to facilitate geometry control. The different strands of work were highly interactive and optimised erection methodologies, developed together with the contractor, led to a successful implementation of the project. [ABSTRACT FROM AUTHOR]