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混凝土 16

三峡工程 7

三峡升船机 4

混凝土面板堆石坝 3

三点弯曲梁 2

低温SOFC 2

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温度 2

温度分布 2

温度控制 2

碾压混凝土坝 2

组合梁 2

高温气冷堆 2

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10kV高压电力电缆 1

700 m跨径级别 1

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Temperature variation of concrete box girder bridge

Jian WANG, Zhi FANG,

《结构与土木工程前沿（英文）》 2009年 第3卷 第4期   页码 407-413 doi: 10.1007/s11709-009-0053-y

摘要： On the basis of theoretical analysis and measurement on site, the temperature gradients and its variation on concrete box girder bridges resulting from ambient temperature, solar radiation, and structural temperature fields were discussed. With the help of the heat transfer theory and finite element method (FEM), the heat flux of the surface of concrete box girder was carried out, and all the heat fluxes were described as the convection. The results were compared with that from field measurements, and a good correlation was found. It was revealed that the methods, the parameters, the boundary condition used in this paper were reasonable. Last, some conclusions were obtained, which could provide the basis for box girder design under solar radiation.

关键词： temperature     transfer     correlation     radiation     variation    

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Energy absorption potential of concrete floors containing secondary (shrinkage and temperature) reinforcements

K. S. SIVAKUMARAN,R. M. KOROL,Xiao FAN

《结构与土木工程前沿（英文）》 2014年 第8卷 第3期   页码 282-291 doi: 10.1007/s11709-014-0269-3

摘要： This paper experimentally investigates the energy absorption potential of two types of concrete floors, namely, normal density concrete and structural low-density concrete, containing secondary (shrinkage and temperature) reinforcements. The test program considered the following secondary reinforcements: 1) traditional welded-wire steel mesh, 2) steel fiber and 3) poly composite fiber. To estimate the extent to which crushing of floor slab materials would help absorb energy, a series of concrete penetration tests employing patch loading was undertaken on scaled down model slabs. Each concrete-secondary reinforcement combination considered slabs of 50 mm in depth with square plan dimensions ranging from 50 to 500 mm, resulting in a total of 30 test specimens. The first part of the paper discusses the test specimens, the test setup, and the test procedure. The second part of the paper presents the experimental results and establishes the energy absorption of different concrete- secondary reinforcement combinations. Sieve analysis results of the crushed specimens were used to derive a “work index” value that relates the pulverized particle size distributions to energy inputs. The work index values of concrete-secondary reinforcement systems can be used to assess the energy dissipation potential associated with such floor slabs in buildings undergoing progressive collapse. The results indicate that floors with secondary reinforcements could play an important role in helping arrest global progressive collapse.

关键词： concrete floors     structural low-density concrete     shrinkage and temperature reinforcements     energy absorption     penetration tests     sieve analysis    

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Experimental investigation on concrete overlaid with textile reinforced mortar: Influences of mix, temperature

《结构与土木工程前沿（英文）》 2023年 第17卷 第2期   页码 271-283 doi: 10.1007/s11709-022-0896-z

摘要： Textile reinforced mortar is widely used as an overlay for the repair, rehabilitation, and retrofitting of concrete structures. Recently, textile reinforced concrete has been identified as a suitable lining material for improving the durability of existing concrete structures. In this study, we developed a textile-reinforced mortar mix using river sand and evaluated the different characteristics of the textile-reinforced mortar under various exposure conditions. Studies were carried out in two phases. In the first phase, the pullout strength, temperature resistance, water absorption, and compressive and bending strength values of three different textile-reinforced mortar mixes with a single type of textile reinforcement were investigated. In the second phase, the chemical resistance of the mix that showed the best performance in the abovementioned tests was examined for use as an overlay for a concrete substrate. Investigations were performed on three different thicknesses of the textile reinforced mortar overlaid on concrete specimens that were subjected to acidic and alkaline environments. The flexural responses and degradations of the textile reinforced mortar overlaid specimens were examined by performing bending tests. The experimental findings indicated the feasibility of using textile reinforced mortar as an overlay for durable concrete construction practices.

关键词： textile reinforced mortar     bending tests     acid and alkaline environment     concrete overlay    

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Field test on temperature field and thermal stress for prestressed concrete box-girder bridge

Baoguo CHEN, Rui DING, Junjie ZHENG, Shibiao ZHANG

《结构与土木工程前沿（英文）》 2009年 第3卷 第2期   页码 158-164 doi: 10.1007/s11709-009-0002-9

摘要： A field test was conducted to investigate the distribution of temperature field and the variation of thermal stress for a prestressed concrete (PC) box-girder bridge. The change of hydration heat temperature consists of four periods: temperature rising period, constant temperature period, rapid temperature fall period and slow temperature fall period. The peak value of hydration heat temperature increases with the increasing casting temperature of concrete; the relation between them is approximately linear. According to field tests, the thermal stress incurred by hydration heat may induce temperature cracks on the PC box-girder. Furthermore, the nonlinear distribution of temperature gradient and the fluctuation of thermal stress induced by exposure to sunlight were also obtained based on continuous in-situ monitoring. Such results show that the prevailing Chinese Code (2004) is insufficient since it does not take into account the temperature gradient of the bottom slab. Finally, some preventive measures against temperature cracks were proposed based on related studies. The conclusions can provide valuable reference for the design and construction of PC box-girder bridges.

关键词： box-girder bridge     field test     hydration heat     temperature field     temperature gradient     thermal stress    

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Data driven models for compressive strength prediction of concrete at high temperatures

Mahmood AKBARI, Vahid JAFARI DELIGANI

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 311-321 doi: 10.1007/s11709-019-0593-8

摘要： The use of data driven models has been shown to be useful for simulating complex engineering processes, when the only information available consists of the data of the process. In this study, four data-driven models, namely multiple linear regression, artificial neural network, adaptive neural fuzzy inference system, and nearest neighbor models based on collection of 207 laboratory tests, are investigated for compressive strength prediction of concrete at high temperature. In addition for each model, two different sets of input variables are examined: a complete set and a parsimonious set of involved variables. The results obtained are compared with each other and also to the equations of NIST Technical Note standard and demonstrate the suitability of using the data driven models to predict the compressive strength at high temperature. In addition, the results show employing the parsimonious set of input variables is sufficient for the data driven models to make satisfactory results.

关键词： data driven model     compressive strength     concrete     high temperature    

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Crack detection for wading-concrete structures using water irrigation and electric heating

《结构与土木工程前沿（英文）》 2023年 第17卷 第3期   页码 368-377 doi: 10.1007/s11709-022-0926-x

摘要： Cracking in wading-concrete structures has a worse impact on structural safety compared with conventional concrete structures. The accurate and timely monitoring of crack development plays a significant role in the safety of wading-concrete engineering. The heat-transfer rate near a crack is related to the flow velocity of the fluid in the crack. Based on this, a novel crack-identification method for underwater concrete structures is presented. This method uses water irrigation to generate seepage at the interface of a crack; then, the heat-dissipation rate in the crack area will increase because of the convective heat-transfer effect near the crack. Crack information can be identified by monitoring the cooling law and leakage flow near cracks. The proposed mobile crack-monitoring system consists of a heating system, temperature-measurement system, and irrigation system. A series of tests was conducted on a reinforced-concrete beam using this system. The crack-discrimination index ψ was defined, according to the subsection characteristics of the heat-source cooling curve. The effects of the crack width, leakage flow, and relative positions of the heat source and crack on ψ were studied. The results showed that the distribution characteristics of ψ along the monitoring line could accurately locate the crack, but not quantify the crack width. However, the leakage flow is sensitive to the crack width and can be used to identify it.

关键词： structural health monitoring     underwater concrete structure     fiber Bragg grating     crack detection     temperature tracer method    

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Effect of anisotropic characteristics on the mechanical behavior of asphalt concrete overlay

Lingyun YOU, Zhanping YOU, Kezhen YAN

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 110-122 doi: 10.1007/s11709-018-0476-4

摘要： Asphalt concrete (AC) overlays placed over old asphalt pavement have become an alternative to repairing and reinforcing pavements. The strength contributed by the AC overlay is strongly influenced by the anisotropic properties of the pavement material. This study was conducted to analyze the influence of anisotropy, modulus gradient properties, and the condition of the AC overlay and old pavement contact plane on the mechanical behaviors of AC overlays, as well as to quantify the influence of the degree of anisotropy on the mechanical behaviors of AC overlay by a sensitivity analysis (SA). The mechanical behaviors of the AC overlay were numerically obtained using the three-dimensional finite element method with the aid of ABAQUS a commercial program. Variations in the AC overlay’s modulus as a function of temperature as well as the contact state between the AC overlay and AC layer were considered. The SA is based on standardized regression coefficients method. Comparing the mechanical behavior in terms of surface deflection, stress, and strain of the anisotropy model against those corresponding to the isotropic model under static loads show that the anisotropic properties had greater effects on the mechanical behavior of the AC overlay. In addition, the maximum shear stress in the AC overlay was the most significant output parameter affected by the degree of anisotropy. Therefore, future research concerning the reinforcement and repair of pavements should consider the anisotropic properties of the pavement materials.

关键词： asphalt concrete overlay     anisotropy     temperature gradients     modulus gradients     finite element simulation     sensitivity analysis    

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Biaxial tensile-compressive experiment of concrete at high temperatures

SONG Yupu, ZHANG Zhong, QING Likun, YU Changjiang

《结构与土木工程前沿（英文）》 2007年 第1卷 第1期   页码 94-98 doi: 10.1007/s11709-007-0009-z

摘要： Biaxial tension-compression experiments of concrete of five stress ratios at high temperatures were carried out using the large static-dynamic triaxial test system in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology. The stress ratios s1/s3 are 0, 0.1, 0.25, 0.50, and 0.75. The temperatures are 20vH, 200vH, 300vH, 500vH, 600vH. The mechanical behavior of concrete under biaxial tension-compression at high temperatures is analyzed. It is found that both the tensile strength and strain diminished with the increase in temperature under each stress ratio. Based on the test results, the relationship between tensile strengths and stress ratios and temperature is proposed. In addition, the failure criterion of concrete under biaxial stress state of tension-compression at high temperatures is established.

关键词： increase     Offshore Engineering     temperature     relationship     addition    

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Modelling autogenous expansion for magnesia concrete in arch dams

JIN Feng, LUO Xiaoqing, ZHANG Chuhan, ZHANG Guoxin

《结构与土木工程前沿（英文）》 2008年 第2卷 第3期   页码 211-218 doi: 10.1007/s11709-008-0025-7

摘要： Magnesia Concrete is a kind of expansive concrete used in Chinese hydraulic engineering more and more widely. To evaluate the effects of autogenous expansion on the stresses of arch dams, a simple model of autogenous expansion for Magnesia Concrete in dam engineering is presented. This model is based on three assumptions: 1) the total amount of autogenous expansion of Magnesia Concrete is related only to the properties of materials and mixing of concrete; 2) the autogenous expansion of Magnesia Concrete is irreversible due to the irreversibility of hydration reaction of Magnesia in the concrete; 3) the autogenous expansion strain rates of Magnesia Concrete bear a relation between temperature and residual Magnesia per unit volume of concrete. The model is verified by some experimental data of autogenous expansion of Magnesia Concrete and field-measured data of an arch dam in China. Embedded into finite element arch dam simulation software, this model is employed to simulate the effects of autogenous expansion of Magnesia Concrete in hydraulic engineering.

关键词： field-measured     irreversibility     temperature     irreversible     element arch    

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Analysis of arch dam deformations

Franz PERNER, Pius OBERNHUBER,

《结构与土木工程前沿（英文）》 2010年 第4卷 第1期   页码 102-108 doi: 10.1007/s11709-010-0012-7

摘要： Predicting “regular” dam deformations for prevailing conditions and comparing them with observed deformations is an essential part of dam surveillance. In many cases prediction and comparison are carried out automatically and an alarm is triggered in the case of larger deviations.The main contributors to the deformations of arch dams are water loading and the fluctuation of concrete temperature. In general, the deformations exhibit an instantaneous elastic part, a time dependent reversible part and an irreversible part. Prediction of dam deformations can be based on deterministic models, purely statistical models or so-called hybrid models, which are a combination of the first two. Deterministic models rely on static analyses, statistical models on the statistical analysis of previous deformation data.For annual reservoirs, both water loading and temperature vary in cycles over a period of one year and it is extremely difficult to identify the various factors contributing to an observed deformation. This is particularly true for time-dependent reversible displacements due to the water loading and the portion caused by temperature variation.The present article deals with the analysis of arch dam deformations based on hybrid models. Particular attention is given to the analysis of the deformations due to temperature fluctuation and to the long-term deformations. The proposed procedure is employed for the analysis of the deformations of the 186 m high Zillergruendl arch dam.

关键词： arch dam     analysis     Zillergruendl     concrete temperature     hybrid model    

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三峡升船机塔柱混凝土温控防裂技术

杨富瀛,冯晓琳,李晓萍

《中国工程科学》 2013年 第15卷 第9期   页码 55-58

摘要：

三峡升船机塔柱结构复杂，属于高层薄壁结构，混凝土温度受环境温度影响较大，其混凝土温控难度极大。在施工实践中，通过优化混凝土配合比、合理布置混凝土冷却系统、科学调控冷却水温度与通水时间，科学调整外部环境温度、同时引进混凝土养护新材料、新工艺，并且加强对温控的施工管理等措施，保证了塔柱混凝土的施工质量，证明了温控方案的科学合理性。三峡升船机塔柱混凝土温控防裂技术对研究国内外升船机工程温控措施技术水平，提高水电工程混凝土施工质量，节省工程造价等具有重要的参考价值。

关键词： 升船机塔柱     混凝土     温控     防裂     三峡升船机    

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大体积混凝土受寒潮袭击时半无限平面问题的无限平面化

黄达海,王从峰

《中国工程科学》 2002年 第4卷 第7期   页码 33-39

摘要：

在分析混凝土表面裂缝特点的基础上，针对受寒潮袭击中的大体积混凝土，提出表面裂缝问题的半无限平面假设。利用混凝土传热的延迟性质，研究了任意降温过程中半无限平面问题无限平面化的条件。采用叠加原理，提出了环境温度任意下降时混凝土表面温度及表层温度计算的新方法。利用400mm×400 mm×220 mm块状试件，构造了混凝土表面开裂问题的半无限平面模型。在室外环境下，对混凝土表面温度与表层温度进行了连续测量，并对该方法进行了验证。试验结果表明，在环境温度单调下降的条件下，对混凝土受寒潮袭击时的半无限平面问题进行无限平面化处理是可行的。

关键词： 混凝土     表层温度     半无限平面问题     降温过程     条件等价性     模型试验    

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Deep learning model for estimating the mechanical properties of concrete containing silica fume exposed

Harun TANYILDIZI, Abdulkadir ŞENGÜR, Yaman AKBULUT, Murat ŞAHİN

《结构与土木工程前沿（英文）》 2020年 第14卷 第6期   页码 1316-1330 doi: 10.1007/s11709-020-0646-z

摘要： In this study, the deep learning models for estimating the mechanical properties of concrete containing silica fume subjected to high temperatures were devised. Silica fume was used at concentrations of 0%, 5%, 10%, and 20%. Cube specimens (100 mm × 100 mm × 100 mm) were prepared for testing the compressive strength and ultrasonic pulse velocity. They were cured at 20°C±2°C in a standard cure for 7, 28, and 90 d. After curing, they were subjected to temperatures of 20°C, 200°C, 400°C, 600°C, and 800°C. Two well-known deep learning approaches, i.e., stacked autoencoders and long short-term memory (LSTM) networks, were used for forecasting the compressive strength and ultrasonic pulse velocity of concrete containing silica fume subjected to high temperatures. The forecasting experiments were carried out using MATLAB deep learning and neural network tools, respectively. Various statistical measures were used to validate the prediction performances of both the approaches. This study found that the LSTM network achieved better results than the stacked autoencoders. In addition, this study found that deep learning, which has a very good prediction ability with little experimental data, was a convenient method for civil engineering.

关键词： concrete     high temperature     strength properties     deep learning     stacked auto-encoders     LSTM network    

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Temperature and structural responses of a single-section utility tunnel throughout fire exposure

Yanmin YANG; Ying XIONG; Yongqing LI; Xiangkun MENG; Peng WANG; Tianyuan CAI

《结构与土木工程前沿（英文）》 2022年 第16卷 第10期   页码 1351-1364 doi: 10.1007/s11709-022-0857-6

摘要： In this study, fire tests of four single-section scaled-down utility tunnels were conducted. By analyzing temperature and structural responses of the utility tunnel throughout the fire exposure, the effects on the fire behavior of two different construction methods, cast-in-situ and prefabricated, and of two different materials, ordinary concrete and full lightweight concrete, were explored. The results of the study showed that the shear failure of the cast-in-situ utility tunnel occurred at the end of the top or bottom plate, and the failure of the prefabricated utility tunnel occurred at the junction of the prefabricated member and post-cast concrete. As the temperature increased, the temperature gradient along the thickness direction of the tunnel became apparent. The maximum temperature difference between the inner and outer wall surfaces was 531.7 °C. The highest temperature occurred in the cooling stage after stopping the heating, which provided a reference for the fire protection design and rescue of the utility tunnel. The displacement of the top plate of the prefabricated utility tunnel was 16.8 mm, which was 41.8% larger than that of the cast-in-situ utility tunnel. The bearing capacities of the ordinary concrete utility tunnel and full lightweight concrete utility tunnel after the fire loss were 27% and 16.8%, respectively. The full lightweight concrete utility tunnel exhibited good ductility and fire resistance and high collapse resistance.

关键词： full lightweight concrete     construction methods     temperature response     structural response     fire test    

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Key technical innovations in the construction of Baihetan Hydropower Station Project

《工程管理前沿（英文）》 2023年 第10卷 第2期   页码 367-372 doi: 10.1007/s42524-023-0253-5

摘要： Key technical innovations in the construction of Baihetan Hydropower Station Project

关键词： ultra-high arch dam     columnar jointed basalt     low-heat cement concrete     temperature controlled crack prevention     million-kilowatt unit     intelligent construction    

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标题 作者 时间 类型 操作

Temperature variation of concrete box girder bridge

Jian WANG, Zhi FANG,

期刊论文

Energy absorption potential of concrete floors containing secondary (shrinkage and temperature) reinforcements

K. S. SIVAKUMARAN,R. M. KOROL,Xiao FAN

期刊论文

Experimental investigation on concrete overlaid with textile reinforced mortar: Influences of mix, temperature

期刊论文

Field test on temperature field and thermal stress for prestressed concrete box-girder bridge

Baoguo CHEN, Rui DING, Junjie ZHENG, Shibiao ZHANG

期刊论文

Data driven models for compressive strength prediction of concrete at high temperatures

Mahmood AKBARI, Vahid JAFARI DELIGANI

期刊论文

Crack detection for wading-concrete structures using water irrigation and electric heating

期刊论文

Effect of anisotropic characteristics on the mechanical behavior of asphalt concrete overlay

Lingyun YOU, Zhanping YOU, Kezhen YAN

期刊论文

Biaxial tensile-compressive experiment of concrete at high temperatures

SONG Yupu, ZHANG Zhong, QING Likun, YU Changjiang

期刊论文

Modelling autogenous expansion for magnesia concrete in arch dams

JIN Feng, LUO Xiaoqing, ZHANG Chuhan, ZHANG Guoxin

期刊论文

Analysis of arch dam deformations

Franz PERNER, Pius OBERNHUBER,

期刊论文

三峡升船机塔柱混凝土温控防裂技术

杨富瀛,冯晓琳,李晓萍

期刊论文

大体积混凝土受寒潮袭击时半无限平面问题的无限平面化

黄达海,王从峰

期刊论文

Deep learning model for estimating the mechanical properties of concrete containing silica fume exposed

Harun TANYILDIZI, Abdulkadir ŞENGÜR, Yaman AKBULUT, Murat ŞAHİN

期刊论文

Temperature and structural responses of a single-section utility tunnel throughout fire exposure

Yanmin YANG; Ying XIONG; Yongqing LI; Xiangkun MENG; Peng WANG; Tianyuan CAI

期刊论文

Key technical innovations in the construction of Baihetan Hydropower Station Project

期刊论文