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In order to quantitatively calculate the critical depth and critical load of mines affected by rock burst, and to achieve effective prevention and control of rock burst in coal mines, this paper proposes a mechanical model for predicting the occurrence of rock burst in coal mine roadways based on catastrophe theory. Additionally, a theoretical calculation formula for initiating rock burst is derived. The first step was to establish a mechanical analysis model, which directly correlated with the in-situ stress, physical and mechanical characteristics of the coal-rock mass, and engineering structural parameters. Following this, a mechanical instability criterion was derived for the key load-bearing circle within the surrounding rock of the roadway. In the final step, the critical depth and load for rock burst initiation were verified for 25 distinct coal mines in China that were prone to rock burst hazards. The research results demonstrate that the discrepancy between the theoretically calculated critical depth and the actual measured statistical values was less than 35%. In addition, the difference between the theoretically determined critical depth and the value calculated by Pan Yishan was less than 32%. Notably, the ratio of the theoretically calculated critical load to the uniaxial compressive strength of the coal-rock mass ranged from 0.38 to 1.93. This aligns with empirical data on rock burst occurrences, as set out in the engineering classification standards for rock masses. These research outcomes substantiated the practical utility of the proposed theory, thereby laying a robust theoretical groundwork for the quantitative control of rock burst. [ABSTRACT FROM AUTHOR]

Space grid structures are widely used in the field of structural engineering due to their good mechanical properties and simple construction procedures. This paper reviews the development of space grid structures and mainly introduces the development of space grid structures in China in recent years. Some typical applications of space grid structures are introduced and the technical developments are summarized. It shows that China not only has a large number of engineering applications of space grid structures, but also a rapid development of related technologies. Finally, some prospects for space grid structures are discussed. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to reveal the corrosion mechanism and corrosion development regulation of marine engineering structural steel in the marine environment and provide constructive suggestions for marine immersed tunnel engineering. Design/methodology/approach: In this study, marine engineering structural steel's behavior and corrosion prediction were carried out under the conditions of no cathodic protection and under-protection by artificially adding dissolved oxygen in a simulated seawater solution as a depolarizing agent. Findings: Marine resources are rich in China. With the development of the economy and the improvement of engineering technology, marine engineering structural steel is used more and more widely. Engineering structural steel has a great risk of corrosion failure for long-term service in seawater, as seawater is a kind of corrosive medium containing various salts. At present, there are few projects and research studies available on the corrosion in the seawater environment of Q390C engineering structural steel, which is used in the Shenzhen–Zhongshan Link immersed tunnel steel shell at home and abroad. It cannot guide the corrosion of immersed tunnel steel shells in the ocean. Originality/value: In this paper, the corrosion mechanism and corrosion development regulation of marine engineering structural steel in the marine environment are studied by accelerated corrosion test in the laboratory, which is of great significance to ensure the long-life durability of the immersed tunnel in marine engineering. [ABSTRACT FROM AUTHOR]

Nowadays, with the leap-forward development of computer technology and the transformation of information technology management concepts, China's construction industry is quietly entering the era of refined management. Accurate estimation and cost control have become among the key considerations of the construction industry. For the calculation of engineering quantity, there are already many software devices that can be used for the calculation of engineering structure quantity, which means that the incorrect operation of personnel has been reduced to some extent, improving the work efficiency and measurement accuracy. The purpose of this paper is to solve the problems of computational missing, computational errors, inefficiency, data loss, and repetitive system in traditional computing based on the advantages of BIM computing system, which provide a reliable basis for cost forecasting and control. At the same time, using BMI calculation system to solve the problem of steel reinforcement in construction engineering, as well as the use of personnel, the existing calculation software still needs a lot of time and energy. We proposed a comprehensive evaluation study of reinforcement calculation in domestic construction engineering BIM calculation system based on a fuzzy comprehensive evaluation. This paper first summarizes the BIM calculation system of construction engineering, uses fuzzy comprehensive evaluation system as an important evaluation index system in domestic construction engineering BIM calculation system, through the judgment of various factors affecting the actual effect of the calculation system, and uses the fuzzy evaluation system combined with a case to demonstrate the superiority of the proposed research. Therefore, through the above research and experiments, it is concluded that the research method of this paper solves many problems in the process of engineering structure reinforcement calculation and provides a good reference method for the establishment of comprehensive evaluation system of reinforcement calculation, as well as providing an effective validation for the widespread use of BIM technology in the construction industry. Finally, it is also beneficial for users to comprehensively evaluate the BIM calculation system of the construction industry and provide a basic reference condition for different industries to use and choose BIM calculation systems. [ABSTRACT FROM AUTHOR]

The application of composite materials in bogies for high‐speed electric multiple units (EMUs) has been regarded as a technical breakthrough. The application of composite materials in rail vehicles began late in China. Currently, most composite materials are used in non‐load‐bearing components on the track, and applications in bogies, tie beams, and other load‐bearing components are not mature. In this paper, we innovatively apply a design strategy using thin‐ply on the composite bolster of a bogie for a multiple unit to optimize the static strength of the composite structure under very complex loading. We applied nine unconventional loads and 11 major operating loads in total to evaluate a potential positive influence of using thin‐ply on the static strength of the composite bolster of a bogie. The numerical results showed that for all the complex loading scenarios, the application of thin‐ply could effectively improve the static strength of the composite structure, which is more effective at the location of the bolts and holes. The research results break through the traditional design ideas of composite structures and provide an effective ply design and optimization strategy for composite structure design engineering of high‐speed EMU. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Microbially induced carbonate precipitation (MICP) is a remarkable method that creates sustainable cementitious binding material for use in geotechnical/structural engineering and environmental engineering. This is due to the increasing demand for alternative environmentally friendly technologies and materials that result in minimal or zero carbon footprint. In contrast to the previously published literature, through bibliometric analysis, this review paper focuses on the current prospects and future research trends of MICP technology via the Scopus database and VOSviewer analysis. The objective of the study was to determine the annual publications and citations trend, most contributing countries, the leading journals, prolific authors, productive institutions, funding sponsors, trending author keywords, and research directions of MICP. There were a total of 1058 articles published from 2001 to 2021 on MICP. The result demonstrated that the volume of publications is increasing. China, Construction and Building Materials, Satoru Kawasaki, Nanyang Technological University, and the National Natural Science Foundation of China are the leading country, journal, author, institution, and funding sponsor in terms of total publications. Through the co-occurrence analysis of the author keywords, MICP was revealed to be the most frequently used author keyword with 121 occurrences, a total link strength of 213, and 152 links to other author keywords. Furthermore, co-occurrence analysis of text data revealed that researchers are concentrating on four important research areas: precipitation, MICP, compressive strength, and biomineralization. This review can provide information to researchers that can lead to novel ideas and research collaboration or engagement on MICP technology. [ABSTRACT FROM AUTHOR]

As one of the severe natural disasters, typhoon hazard brings tremendous tragedy to human beings. The foreland in the southeast of China is one of the most typhoon prone areas in the world. There are amount of damage of civil engineering structures induced by typhoon every year. Especially for the spacious villages, the low-rise buildings are vulnerable to typhoon so that many of them are destroyed regionally. The typhoon vulnerability assessment of civil engineering structures is a classical multiple attribute group decision making (MAGDM) issues. In this paper, the 2-tuple linguistic neutrosophic number grey relational analysis (2TLNN-GRA) method is built based on the grey relational analysis (GRA) and 2-tuple linguistic neutrosophic sets (2TLNSs) with incomplete weight information. For deriving the weight information of the attribute, an optimization model is built on the basis of the GRA, by which the attribute weights can be decided. Then, the optimal alternative is chosen through calculating largest relative relational degree from the 2-tuple linguistic neutrosophic number positive ideal solution (2TLNNPIS) which considers both the largest grey relational coefficient (GRC) from the 2TLNNPIS and the smallest GRC form 2-tuple linguistic neutrosophic number negative ideal solution (2TLNN NIS). Then, combine the traditional fuzzy GRA model with 2TLNNSs information, the 2TLNN-GRA method is established and the computing steps for MAGDM are built. Finally, a numerical example for typhoon vulnerability assessment of civil engineering structures has been given and some comparisons is used to illustrate advantages of 2TLNN-GRA method. [ABSTRACT FROM AUTHOR]

A path for testing a probabilistic seismic hazard assessment (PSHA) map is presented in this paper via the evaluation of fortification benefit with two indices, economic benefit and safety benefit. The effect of fortification intensity on the vulnerability of the engineering structure is emphasized in the damage estimation of the evaluation. The expected losses and casualties are calculated based on the total areas in each of the five damage states with local parameters. The result of a case study of the 1990 PSHA map of China shows that the expected total reduction of loss from the damage to brick concrete and reinforced concrete buildings constructed during the in-service period of the map and damaged in the subsequent destructive earthquakes is RMB 216.5 billion. Thus the expected economic benefit is RMB 17.5 billion in comparison to the additional fortification cost of RMB 199.0 billion. The expected casualty reductions are 20,838 fewer deaths and 77,801 fewer serious injuries. This indicates that the implementation of the 1990 PSHA map has indeed played a beneficial role in earthquake disaster mitigation. The evaluation result of the marginal benefit of fortification, in terms of increasing or decreasing the fortification intensities by one degree further for the whole country, shows that the fortification level adopted in China is appropriate as a whole. [ABSTRACT FROM AUTHOR]

Due to the influence of regional climatic conditions, the development of cold ecological tourism agricultural park in the north is slow, its landscape planning and design research lags behind, and there are still some problems. With the development of electronic computers, the previously unachievable optimization of engineering structures is now possible, while the traditional optimization methods cannot meet the requirements of modern computing due to the implementation constraints. The emergence of algo for group intelligences has made some applications of engineering structural optimization possible. Group intelligence is the characteristic of a system in which the collective behavior of low-level individuals interacting locally with their environment forms an overall pattern of consistent functions. This paper presents a study of energy-efficient cold landscape design based on algo for group intelligences and analyzes the problems that arise in the ecological landscape design of cold urban settlements. Then countermeasures are proposed to solve the problems. The linear model is replaced by the determination of the weight of the evaluation index of the energy-saving design of frozen landscape. And take it as a new migration model. Then, based on the weight of the evaluation index, the group algorithm analysis in landscape design is proposed, which is a generalized definition of the standard model. The experimental results show that the algo for group intelligence outperforms another algorithm in terms of solving ability to the extent that the average optimization ability is improved by 13.45%, so the algo for group intelligence demonstrates its superior ability to take into account both local and global search. Therefore, the use of algo for group intelligences to build an energy-efficient society is a necessary path for China's development, and the construction of energy-efficient gardens is an important part of building an energy-efficient society, and the application of energy-efficient concepts to modern landscape design is an inevitable trend in the development of urban landscaping. [ABSTRACT FROM AUTHOR]

The rapid development of complex space steel structure buildings has brought new challenges to structural fire protection analysis and design. On the basis of analyzing the deficiencies of structural fire protection design in existing normative and performance-based design methods and based on the knowledge and research results of fire science, structural engineering, computer simulation, and other disciplines, this paper proposes an improved Gaussian transformation model and applied it to the overall fire performance analysis of this complex space steel structure. The proposed model is based on theoretical research and practical application of the simulation and analysis of the overall fire performance of complex spatial buildings. The coupled analysis model and system integration method of spatial overall structure fire and structure are established. The improved Gaussian transformation model is used to propose the integrity of complex spatial structures. It is a system analysis model for fire analysis. The experimental results show that the designed algorithm model can effectively realize the overall fire performance analysis of complex spatial steel structures and can provide a useful reference for China's building fire protection research, building fire protection design, fire rescue, emergency plan formulation, and other engineering practical applications. [ABSTRACT FROM AUTHOR]

Long-span cable-supported bridge is one of crucial transportation infrastructures. Structural health monitoring (SHM) system that is used to assess structural service conditions and detect early damage has drawn a growing attention in engineering structural society. It provides a real-time monitoring of various structural changes under operational and extreme conditions. Yangluo Bridge over Yangtze River in Wuhan city of China is a 1280 m central span suspension bridge with an orthotropic steel box girder. Taking the SHM system of Yangluo Yangtze River Bridge as an example, this paper presents an implementation of SHM system on the bridge in terms of sensor layout, data acquisition strategy, data transmission, data processing, and abnormal alarm framework. With such an SHM system, the typical monitoring results are demonstrated such as operational environments, loadings, structural deformation, strains, dynamic properties, and structural responses. The SHM system of Yangluo Yangtze River Bridge is continuously gathering data and monitoring structural behavior. It is anticipated that it will provide either scientific or technological supports to the service comfort and safety of the bridge. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The HUBα-Sightseeing Gate in Guangzhou, which is a connected tall building structure, is composed of two main frame-shear wall towers, which are 865 m high, and two steel galleries at top and bottom, respectively. The top gallery is a 120 m long-span steel truss. Vicious dampers are set in the two main towers and the top gallery. It is an ultra-limit structure with complicated structural shape and hybrid structure system. Design idea of performance-based seismic design is presented in this paper. Seismic performance of the structure under different levels of ground motion is analysed and verified by different methods, such as elastic analysis under frequent earthquake, unyielding and elastic check of structure element under medium earthquake and inelastic dynamic time history analysis under rare earthquake. Taking the result of shaking table test as a reference, reasonable enhanced measures of seismic design are suggested. Meanwhile, wind-induced vibration time history analysis under different directions based on wind tunnel test is applied in this paper, and comfortableness problem can be well resolved. The control effects of vicious dampers on internal force, deformation, acceleration and energy dissipation of the structure are also studied. By means of the analysis methods mentioned above, and other analyses such as whole structure stability, temperature effect, floor vibration and so on, relevant measures of ultra-limit structure design are suggested, and the performance objective of the structure can be well realized. [ABSTRACT FROM AUTHOR]

Seismic intensity measures are essential quantitative parameters for evaluating and predicting engineering structures' seismic risk and vulnerability. Various regional earthquake analysis and vulnerability models with evaluation and prediction capabilities have been developed using macroseismic and instrumental intensity measures. These results have significant positive implications for evaluating large-scale regional earthquake resilience and predicting earthquake risks. However, the traditional determination of seismic intensity measures is based on given seismic station detection data and macroscopic intensity standards, and the developed seismic risk models are relatively outdated, resulting in relatively low accuracy in assessing the vulnerability of regional structures. This paper proposed an improved instrumental intensity calculation equation and updated the model using 216,000 acceleration records monitored by nine typical seismic stations in China during the Jiuzhaigou earthquake on August 8, 2017. The proposed calculation model was combined with the latest version of China's macrointensity standard, and undamaged building samples were sufficiently considered. The vulnerability level of 1,499 buildings surveyed in the Jiuzhaigou earthquake was assessed. This paper innovatively proposed a membership index calculation model to estimate the impact relationship between different vulnerability levels. A comparative curve model was generated with the updated vulnerability databases of four typical regional structures, considering different vulnerability membership indices. Using the improved seismic intensity measures and nonlinear regression model, an improved vulnerability fitting model was developed to assess the seismic risk of regional structures. The model was analysed and verified using field survey data from the Jiuzhaigou earthquake. • This work improves old seismic intensity measures and proposes an instrument intensity model. • An index calculation model of vulnerability membership is innovatively proposed. • The outdated seismic vulnerability regression model has been improved. • A relatively reasonable optimized Gaussian distribution model is proposed. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The successful adoption of building information modelling (BIM) technology has led to an ever-increasing need for improving management practices in both construction and operation stages of highway project engineering. The most significant aspect of applying BIM technology is establishing the rationality and concise engineering breakdown structure (EBS) coding. However, China has no uniform EBS coding standard for highways, which limits BIM technology development in different construction projects and at different stages of the same construction project. The purpose of this study is to propose an EBS standard that embodies a coding system for highways and at the same time meets the requirements of BIM management, project management (PM), and operation management (OM) in life cycle management process. This paper presents an EBS standard based on three classifications: (1) project-level construction, (2) project-level operation, and (3) network-level operation. A case study is given to illustrate the proposed EBS standard's coding system. The new EBS system will have better adaptability in both the design and construction stages. The proposed EBS coding system has been applied in many projects and is undergoing both improvement and standardization in China. The presented EBS coding standard provides successful implementation references for the future adoption and use of BIM on PM and OM in highway projects. [ABSTRACT FROM AUTHOR]

At present, China is the world's largest producer of bamboo resource possessor and bamboo processing. The main processing method of bamboo recombination technology is rolling and compaction, by which a reconstituted material with bamboo fibrotic veneer as matrix and phenolic resin as reinforcement is prepared. It has excellent physical and mechanical properties and can replace high-quality wood to manufacture various engineering structural materials and building decoration materials. This paper reviewed the research process and progress of bamboo recombination technology, the existing technical problems and prospects, in order to provide references for future research on bamboo recombination theory and production practice. In recent years, as a new material with controllable properties, designable structures, and adjustable dimensions, bamboo reconstituted materials have been comprehensively studied from the aspects of pressing process parameters, physicochemical mechanical properties evaluation system, and microstructure characterization, but the research is not comprehensive and has not in-depth view. In the future, the relationship between microstructure and performance should be emphatically studied to clarify the law of mechanical performance change and ultimate mechanical performance under synergistic enhancement effect, as well as the performance change and interface formation of the resin during the entire molding process. Meanwhile, the reliability and relevance of applied research should be further expanded, and the integration of natural and artificial aging environment, process and performance, and macro- and microscales should be strengthened. [ABSTRACT FROM AUTHOR]

The effective control of large roadway deformations has always been a focus and difficulty in the coal industry. At present, a "bolt + cable + mesh + shotcrete" combined support structure has been widely used in China to support roadways with large deformations, and this method has achieved some success. However, large roadway deformations supported by using the "bolt + cable + mesh + shotcrete" support structure still have a series of engineering problems. This paper describes a case study of large deformation control in a roadway surrounded with broken rock located in the Du'erping coal mine in the Shanxi Province of China. A new "shell + bolt + shotcrete" combined support structure is proposed to support the north wing main haulage roadway. Methods were adopted from theoretical analysis, numerical simulation, and similarity simulation experiments to design a reinforced shell within a vertical wall semicircular arch. Roadway convergence and surrounding rock stress were monitored on the site. The monitoring data showed that the new support structure successfully controlled a potentially large deformation of the roadway. This new combined support structure provides a helpful reference for the design and engineering of support structures to prevent large roadway deformations. [ABSTRACT FROM AUTHOR]

As a result of rapid economic growth and urbanization in the past two decades, many tall buildings have been constructed in China Mainland, offering researchers and practitioners an excellent opportunity for research and practice in the field of structural engineering. This paper reviews progress by researchers throughout China Mainland on the seismic research of tall buildings, focusing on three major topics that impact the seismic performance of tall buildings. These are: (1) new types of steel-concrete composite structural members such as steel-concrete composite shear walls and columns, (2) earthquake resilient shear wall structures such as shear walls with replaceable structural components, self-centering shear walls and rocking walls, and (3) performance-based seismic design, including seismic performance index, performance level and design method. The paper concludes by presenting future research needs and directions in this field. [ABSTRACT FROM AUTHOR]

Lateral berms are often constructed to protect highway bridges against debris flows in mountainous regions. Currently, different solutions for lateral berm design are debated. The lack of standardization results in the improper design of lateral berms, limiting the mitigating effect. In this paper, a monitoring case of the mitigating effect of a lateral berm is introduced. The lateral berm was constructed through a bridge culvert at the alluvial fan of a debris-flow gully. In September 2008, a debris flow in this gully completely buried the lateral berm. The proposed numerical integral method was used to back analyse the flowing velocity and mud depth in berm. Results supported the speculation that abrupt decreases in mud depth and flow velocity in the lateral berm caused deposits that compressed the effective berm depth and resulted in overtopping flow. Therefore, we suggested reducing the berm width in order to increase the flow velocity in the berm. In June 2011, another debris flow with a smaller magnitude occurred in the gully, and the reconstructed lateral berm reportedly performed well to protect the bridge of Yalu highway. The case studies highlighted that berm width should be one of the main considerations in the berm design. [ABSTRACT FROM AUTHOR]

This paper reports the results of a series of material performance tests undertaken to compare Chinese and Australian 500 MPa reinforcing steel. After providing some background to modern high strength reinforcing steel, this paper compares the chemical and mechanical requirements of the reinforcing steels in Chinese codes with those in Australian standards. The results of tensile strength and ductility tests are reported. From the requirements of the standards and the analysis of the test data, several conclusions are drawn. Small differences in the chemical composition cause some differences in mechanical properties. Because of the higher percentage of carbon, the tensile strength of Chinese reinforcing steel is generally higher than that of Australia's normal ductility (N) reinforcing steel. The ductility of Australia's normal ductility reinforcing steels is somewhat less than that of Chinese reinforcing steels, due to the higher percentages of the chemicals phosphorous and sulphur. However, because of the lower value of Ceq and carbon content, the weldability of Australian steel is higher than Chinese steel. By adding the trace elements V, Nb and Ti into the steels, the seismic ability of Chinese steels has been improved. Both Chinese and Australian reinforcing steels tested had adequate yield stress levels. In each country the test results indicated that the tested steel achieved the requirements of the applicable standard. [ABSTRACT FROM AUTHOR]

Four suspension bridges stiffened by prestressed concrete slabs were designed and constructed on highways in southwestern mountainous areas of China. These bridges are the first applications of its kind in China. This paper discusses the site condition, adaptability, and design and construction features of these bridges. These bridges have single suspension spans between 278 and 388 m and deck width between 14.4 and 15.0 m. The longitudinal distance between hangers is only 5 m, which is relatively small for this bridge type, and there are only two lanes. The dual direction prestressed concrete slabs are 0.6 m deep, and its wind blocking area is relatively small. Dynamic analysis and wind tunnel tests verify that the wind resistance requirements are easily satisfied. [ABSTRACT FROM AUTHOR]

Excessive and unexpected settlement of supertall buildings during the construction stage may affect structural safety. Floor settlement monitoring is imperative during the structural construction. The current practice is to measure floor settlement within a specific time frame and then compensate for the elevation error in the next construction stage. This posterior manner is inaccurate because it does not take account of measurement error and the real settlement in the next construction stage. This paper presents a Kalman filter based settlement monitoring approach with the aid of forward construction stage analysis. The settlement of floors in the next stage is predicted with the forward construction stage analysis. Consequently the elevation of the floor to be constructed can be pre-determined. The proposed method is demonstrated through construction settlement monitoring of the 632-m tall Shanghai Tower. The structure will be the tallest supertall building of China upon completed in 2014. It shows that this method can improve the accuracy of pre-determined elevation of supertall buildings. [ABSTRACT FROM AUTHOR]

Though a large amount of research has been carried out on recycled aggregate concrete (RAC) during recent years, the application cases of RAC in real structures are still very few in China. This paper reports the application of RAC in a real project. Two beams made of RAC and commercial natural aggregate concrete (NAC) respectively were cast in-situ to carry out the tests. The two beams were subjected to the similar service loading, so that the performance of the RAC beam could be compared with that of the NAC one. Compressive strength, degree of density and uniformity were tested for both types of concrete at representative ages, and concrete strain of the two target beams was monitored regularly from the age from 1 d to 420 d. The results from laboratory tests and on-site monitoring have proved the feasibility and reliability of the application of RAC in real structures though RAC is generally inferior to NAC. [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]

This paper describes a simplified analytical method that considers postinstallation normal stress, normal stress due to soil dilation, and grouting pressure when calculating the maximum shear stress of the nail-soil interface. Systematic test results from two previous publications were used to verify the accuracy of the proposed method. The Hong Kong design method was also used to determine the maximum shear stress of the nail-soil interface. These analyses confirmed that the experimental data were more accurately predicted by the proposed analytical method. An extensive parametric study was conducted to examine the effects of several key parameters on the maximum shear stress. It was observed that when there was no grouting pressure, maximum shear stress increased with increasing overburden pressure, failure surface distance, dilation angle, or decreased drill hole radius. Analysis using the proposed model also demonstrates that grouting and overburden pressures share an interactional effect. The larger the grouting pressure, the greater the influence of the overburden pressure; and, consequently, the larger the maximum shear stress at the nail-soil interface. [ABSTRACT FROM AUTHOR]

Modern structural engineering tends to progress towards more novel high-rise structures through gradually improved methods of design and wide use of new materials. The National Hall of China Pavilion for Expo 2010 Shanghai is such a building specially designed with a shape of an inverted trapezoid in elevation and local discontinuity of floor slabs in plan for aesthetic and functional considerations. The preliminary analysis shows that the fundamental vibration mode of this structure is a torsional mode due to the special shape, thus resulting in the period ratio between the first torsional mode and the first translational mode exceeding the limit value stipulated in Chinese code. Shaking table tests of a 1/27-scale structural model were performed to observe the seismic response characteristics, and verify the seismic safety of the structure. This paper presents the results of the shaking table tests in terms of dynamic properties, global responses, as well as local responses. It was found that the torsional effects were not significant by the analysis of the ratio between the maximum displacement and the average displacement of floor and torsional angle. Finally, weak points were identified, and some corresponding suggestions were put forward to improve the overall seismic performance of this structure. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Analytical investigation was undertaken to assess the seismic performance of Wenchuan Hospital located in Wenchuan county, southwest China's Sichuan province, where a severe earthquake has occurred in May 2008. The structure consists of a four-storey reinforced concrete frame with viscous dampers. The irregular building is 1835-m tall and has a total floor area of 17000 m2. Viscous dampers are set along the outside surface of structure to get a more efficient reduction of structure responses. The design idea of performance-based seismic design is presented in this paper. Seismic performance of the structure with and without viscous dampers under different levels of ground motion is analysed and verified by different methods, including elastic analysis under frequent earthquake, unyielding and elastic check of structure element under medium earthquake, static nonlinear analysis and dynamic nonlinear analysis under rare earthquake. And a comparative analysis is presented, such as results between elastic and inelastic analysis, static nonlinear analysis and dynamic nonlinear analysis, and structure with and without viscous dampers. The control effects of viscous dampers on internal force, deformation and energy dissipation of the structure are also studied. Meanwhile, a practical method to calculate the supplemental damping ratio added by viscous dampers is proposed for elastic analysis with dampers. After a series of analysis, the performance objective of the structure can be well verified. [ABSTRACT FROM AUTHOR]

Underground mine caving may induce collapse of the ground during ore caving, particularly when there is a loose material on top of the mine. In the present paper, a laboratory test is performed to model this mining problem which is followed by a particle flow simulation to simulate the interaction and movement between the two materials. For this nonhomogeneous problem, an interesting columniform channel for the loose material is formed during the drawing in both the experiment tests and the numerical modeling. The formation of this channel greatly affects the efficiency of ore drawing and the stability of the mine caving. The numerical modeling can be used for the optimization of ore drawing, ore drawing management and the prediction of ore loss and dilution indexes. The importance of the moisture content on ore drawing process and the efficiency of ore drawing are also investigated by both experimental and numerical tests, and useful results are found from the present study. [ABSTRACT FROM AUTHOR]

A new approach to identification of modal damping ratios from free vibration response of a linear structure with viscous damping is proposed in this paper. For a single degree of freedom (dof) system, the formulated relations among areas forming from time history of response are used to determine the damping ratio for the free decay vibration. Comparing with traditional logarithmic-decrement method, the approach in this paper has advantages such as stronger anti-noise ability, higher precision, better stability and convenience. For a multi-dof system, the free vibration response measured at one point on the structure is expressed in an analytical form at first, and then multiplied by e at . Giving the initial value, a can be obtained by Newton's dichotomy or golden section method while the product of the response and e at has equal vibration amplitudes after a period of time. Accordingly, the damping ratio for this mode can be determined. Repeating the above-mentioned process, all damping ratios for different modes can be obtained in the same way. Results of digital simulations and field tests for the Dongting Lake Cable-stayed Bridge in Yueyang show that the approach presented in this paper is effective and practical. [Copyright &y& Elsevier]

Owing to commercial or aesthetic considerations, the shapes of high-rise city buildings are becoming increasingly unique and complicated. This brings challenges to structural engineers in analyzing and predicting their dynamic responses, which are crucial to the safety of the buildings. For these buildings in China, a detailed study, sometimes including shaking table testing, is required to verify the safety and rationality of their design. This paper presents results of a study performed for a high-rise building with a large space in the ground floor and large openings in elevation. The maximum responses of acceleration and deformation were measured and evaluated, as well as the dynamic characteristics, cracking pattern and failure mechanism of the building. In addition, a 3D finite element analysis was carried out and the analytical results were compared with experimental ones to gain a better understanding of the structural behavior. Suggestions regarding the design of this type of structure were also derived from the test results. [ABSTRACT FROM AUTHOR]

Structural health monitoring systems (SHMSs) have been adopted over the past decade to monitor and evaluate the structural health condition of long-span bridges. A SHMS is currently included as a standard mechatronic system in the design and construction of most large-scale and multi-disciplinary bridge projects, such as Stonecutters Bridge and SuTong Bridge in Hong Kong and China. The modular concept used in the design of the SHMSs for Tsing Ma Bridge, Kap Shui Mun Bridge and Ting Kau Bridge has a significant influence on the design of new SHMSs in Hong Kong and China. This modular concept has, however, been enhanced in the detailed design of the SHMS for Stonecutters Bridge by the Highways Department of Hong Kong. This paper introduces the enhanced modular concept of six integrated modules in terms of their respective functional performance requirements. The six integrated modules are the sensory system, the data acquisition and transmission system, the data processing and control system, the structural health evaluation system, the structural health data management system, and the inspection and maintenance system. Finally, it is concluded that a SHMS for long-span bridges should at least be able to monitor the loading and structural parameters set by the bridge designer so that the bridge performance under current and future loadings conditions can be evaluated. Such evaluated results should be able to facilitate the planning of bridge inspection activities, and be able to determine not only the cause of damage, but also the extent of remedial works, once the damage is identified. [ABSTRACT FROM AUTHOR]

With the rapid urbanization process in China, there has been a significant development of urban underground spaces. The pipe-jacking method has gained popularity in various projects due to its advantages such as short construction period, adaptability to different soil conditions, and minimal excavation disturbance. This study focuses on a tunnel project involving double-hole rectangular pipe-jacking under an expressway. Utilizing FLAC software, a three-dimensional numerical model was created to analyze the impact of double-hole pipe-jacking construction on surface settlement and deformation of the expressway. The simulation results were validated by comparing them with field monitoring data. The study also investigated the impact of different construction parameters, such as excavation sequence and the angle of underpassing the expressway, on surface settlement. Additionally, the surface settlement curve at the slope bottom of the expressway exhibits asymmetric distribution and an offset center in the settlement trough. It is recommended to carry out the construction of double-hole pipe-jacking in the sequence of "big first and then small". Furthermore, when the included angle between the expressway and the jacking axis is 90°, the impact on surface settlement is minimized. This research provides valuable insights for the construction of double-hole pipe-jacking underpass structures in tunnel engineering. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on the chemical erosion resistance of geopolymer mortar (GM) to sulphuric acid and sodium chloride attacks. The variations of mechanical properties and mass of geopolymer mortar after soaked in water, sodium chloride and sulphuric acid solutions for different durations (30, 60, 90, 180, 270 and 360 days) were investigated. The test results showed that geopolymer mortar had good resistance to sodium chloride and sulfuric acid erosion solutions. The maximum degradation in flexural, compressive and tensile strength of geopolymer mortar soaked in sodium chloride and sulphuric acid solutions, during the whole soaking duration (360 days) was 6%, 11% and 15% respectively, compared to that in tap water. The strength fluctuation of geopolymer mortar in sulphuric acid solutions was higher than that in sodium chloride solutions. At the first 60 days of immersion, the compressive and tensile strength of geopolymer mortar in tap water, sodium chloride solutions and sulphuric acid solutions decreased, but its strength restored again after 60 days. [ABSTRACT FROM AUTHOR]

The Second Wuhu Bridge is a mega project that will cross the Yangtze River in Anhui Province, China. The main bridge is a cable-stayed bridge with an 806 m main span. Its upcoming connections on both sides are 41.03 km in total. This project needs to be completed within 4 years. To meet this strict time demand, prefabricated, externally prestressed segmental box-girder bridges are utilized using an industrialized method. In this paper, the design and construction of these bridges are introduced. Information about the overall design, cross-sectional design, tendon design, and the precasting and erection techniques are presented. The considerations and optimizations to meet the demands of the industrialized design and construction are explained in detail. [ABSTRACT FROM AUTHOR]

Energy consumption of buildings accounts for more than 37.3% of total energy consumption while the proportion of energy-saving buildings is just 5% in China. In this paper, in order to save potential energy, the building envelope retrofitting is considered. An office building in Southern China was selected as a test example for energy consumption characteristics. The base building model was developed by TRNSYS software and validated against the recorded data from the field work in six days out of August-September in 2013. In addition, with a design of numerical simulation, sensitivity analysis was conducted for energy performance of building envelope retrofitting; six envelope parameters were analyzed for assessing the thermal responses. Results show that significant energy savings are obtained for the thermal transmittance (U-value) of exterior walls, infiltration rate, ventilation and shading coefficient, of which the sum relative sensitivity is about 91.06%. The results are evaluated in terms of energy and economic analysis. On the other hand, it appears that the cost-effective method improves the efficiency of investment management in building energy. [ABSTRACT FROM AUTHOR]

Downbursts occur frequently in mountainous regions, such as the southwest of China, and causing extensive damage to engineering structures. While some researchers have developed semiempirical models for the speedup effect, most are based on the wind field in the boundary layer over the hill, and there is a lack of semiempirical models for the downburst wind field over the hill. This study employs three RANS (Reynolds Average Navier-Stokes) turbulence models to numerically simulate the downburst wind field over a quadratic curved hill. The realizable k-ε model is selected as the optimal model for the subsequent numerical simulations based on comparison with wind tunnel test results. Then, a semiempirical model of the speedup effect of the downburst wind field over the hill is constructed by numerically simulating the downburst wind field over the hill with different radial locations and different slopes. Finally, the constructed semiempirical model is validated and demonstrates good accuracy. [ABSTRACT FROM AUTHOR]

In this study, the uniaxial compressive mechanical properties of earth materials are tested, and the effects of four influencing factors, such as shape, size, curing age, and loading rate, on the strength, damage pattern, and stress-strain curve of the specimens are analyzed. The standard uniaxially compressed specimen size and the recommended loading rate are proposed for the earth specimens. The uniaxial compressive constitutive equations of earth materials are modified on the basis of the Illampas constitutive equation. By fitting the results of this study and typical literature tests, the applicability of the modified constitutive equation form to the uniaxial compressive test curves of soils in different regions of China based on standard sizes is verified. Finally, the formulae for calculating the parameters related to the constitutive equation of earth materials are established. In its application, only the compressive strength of 100-mm-cubic standard specimens with a curing age of 28 d needs to be measured to calculate and determine the specific values of the relevant parameters of the constitutive equation. This is a good reference value for promoting the development of computational analysis methods for earth structures and promoting the engineering design applications of earth structures. [ABSTRACT FROM AUTHOR]

As the weak structure of geotechnical engineering, frozen rock joints determine the stability of geotechnical engineering in frozen region. To study the influencing factors of the peak shear displacement of frozen rock joints, three groups of tuff coupling joints (upper and lower joints completely coincide) are selected in Jiangluling Tunnel, Qinghai Province, China. The joint surface morphology is obtained by three-dimensional scanning technology. The joints are frozen at – 35 ℃ for 12 h before direct shear test. The test results show that there are three main shear failure patterns of frozen rock joints, which are mainly determined by the opening degree of joints. The peak shear displacement decreases with the increase in joints surface roughness and opening degree, and increases with the increase in normal stress. By analyzing the characteristics of peak shear displacement under different opening degrees and normal stress, the influencing factors of peak shear displacement and shear strength of frozen rock joints are discussed. On this basis, the expression of peak shear displacement of frozen rock joints is proposed. It provides a theoretical basis for quantitative study on shear deformation of frozen rock joints. The study provides technical support for geotechnical engineering construction and rock slope instability prevention in frozen region. [ABSTRACT FROM AUTHOR]

In engineering structural design, wind load is of particular importance, and the basic wind pressure is the basis for wind load calculation. Specifications of many countries fail to use the given method to calculate the basic wind pressure for areas or engineering projects with only short-term wind speed data. At the same time, there are few studies on short-term wind speed data fitting by using the extreme value Type III distribution as the distribution law. In this study, the extreme value Type III distribution with variable substitution method and least square method as parameter estimation method is used to fit and analyze the daily, weekly, and monthly maximum wind speed data of 13 major cities in China, when using the Kolmogorov–Smirnov test method to test the results of the fit, it finds that in the wind speed samples of most cities, only the monthly maximum wind speed data obeys the extreme value Type III distribution. By comparing the optimal criterion of estimation, it can be seen that the extreme value Type III distribution fits well with the monthly maximum wind speed data of each city, and the variable substitution method is the most optimal parameter estimation method. The above results show that in areas where long-term wind speed data are insufficient, short-term wind speed data is an available option. Taking the extreme value Type III distribution as the probability distribution, the method of calculating the basic wind pressure of different return periods based on short-term wind speed data is summarized by comparing the specifications of various countries in the world. [ABSTRACT FROM AUTHOR]

Medium- and long-span bridges of the high-speed rail (HSR) projects play a significant role when crossing certain obstacles, such as rivers, existing highways, etc. This paper provides a state-of-the-art review on the design practice of these special spans in the HSR projects of China. Given standard spans are usually smaller than 100m, special spans can be divided into two categories by the length of main span: medium length (100-200m) and large length (200-500m). For medium length, three structural forms are discussed as feasible design options, including steel arch, rigid frame and hybrid arch-girder. In addition, recently completed long-span bridges are reviewed to feature several innovative structural forms on the HSR of China, including steel truss arches and cable-stayed bridges with truss girder. Finally, the key technical features of long-span HSR bridges are summarized, and a discussion of the feasibility of longer spans is also included. [ABSTRACT FROM AUTHOR]

Due to special topographical, geological and meteorological conditions, debris flows occur frequently and result in heavy losses of lives and properties in mountainous areas, which become a great threaten to the sustainable development of regional economy and society in western China. At present, debris-flow prevention has performed well in many mountainous countries and has made headway in early warning, disaster mitigation by structural engineering methods, and risk analysis and management. In this paper, debris-flow prevention techniques have been introduced from the aspects of botanical methods, geotechnical engineering methods, and synthetic prevention system based on the above two methods. In addition, the treatment system of multilevel runoff and unconsolidated soil in the catchment with a chain of "slope-gully-valley" is set up in consideration of sediment load of main rivers, incorporation of slope improvement and gully retention, as well as micro-site factors for matching species with the site. Furthermore, attentions should be paid to the mechanism and technical details of vegetation measures for debris-flow prevention, as well as effective incorporation between botanical method and geotechnical method. [ABSTRACT FROM AUTHOR]