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Construction management and technology innovation for main projects of Quanzhou Bay Bridge

Jun DU, Fangwen WENG

《工程管理前沿(英文)》 2021年 第8卷 第1期   页码 151-155 doi: 10.1007/s42524-020-0147-8

摘要: Hongtao ZHOU, Hongwei WANG, Wei ZENG. [J]. Front. Eng, 2018, 5(1): 78-87.SangHyun LEE. [J]. Front. Eng, 2017, 4(1): 35-40.Bao-long Yuan,Sheng-gang Ren,Xing Hu,Xuan-yu Yang. [J]. Front. Eng, 2016, 3(1): 24-29.Ting Gong,Jian Yang,Hao Hu,Feng Xu. [J]. Front. Eng, 2015, 2(2): 122-124.Hong-yong Liu,Yi-qi Chen,Yi Yang. [J]. Front. Eng, 2015, 2(1): 71-75.Burcu Akinci. [J]. Front. Eng, 2014, 1(3): 283-289.Mao-run Feng,Zheng-song Zhao. [J]. Front. Eng, 2014, 1(1): 42-51.

关键词: construction management     technology innovation     UHPC trestle panel    

Precast steel–UHPC lightweight composite bridge for accelerated bridge construction

Shuwen DENG, Xudong SHAO, Xudong ZHAO, Yang WANG, Yan WANG

《结构与土木工程前沿(英文)》 2021年 第15卷 第2期   页码 364-377 doi: 10.1007/s11709-021-0702-3

摘要: In this study, a fully precast steel–ultrahigh performance concrete (UHPC) lightweight composite bridge (LWCB) was proposed based on Mapu Bridge, aiming at accelerating construction in bridge engineering. Cast-in-place joints are generally the controlling factor of segmental structures. Therefore, an innovative girder-to-girder joint that is suitable for LWCB was developed. A specimen consisting of two prefabricated steel–UHPC composite girder parts and one post-cast joint part was fabricated to determine if the joint can effectively transfer load between girders. The flexural behavior of the specimen under a negative bending moment was explored. Finite element analyses of Mapu Bridge showed that the nominal stress of critical sections could meet the required stress, indicating that the design is reasonable. The fatigue performance of the UHPC deck was assessed based on past research, and results revealed that the fatigue performance could meet the design requirements. Based on the test results, a crack width prediction method for the joint interface, a simplified calculation method for the design moment, and a deflection calculation method for the steel–UHPC composite girder in consideration of the UHPC tensile stiffness effect were presented. Good agreements were achieved between the predicted values and test results.

关键词: accelerated bridge construction     ultrahigh-performance concrete     steel–UHPC composite bridge     UHPC girder-to-girder joint    

Innovative steel-UHPC composite bridge girders for long-span bridges

Xudong SHAO, Lu DENG, Junhui CAO

《结构与土木工程前沿(英文)》 2019年 第13卷 第4期   页码 981-989 doi: 10.1007/s11709-019-0531-9

摘要: Steel and steel-concrete composite girders are two types of girders commonly used for long-span bridges. However, practice has shown that the two types of girders have some drawbacks. For steel girders, the orthotropic steel deck (OSD) is vulnerable to fatigue cracking and the asphalt overlay is susceptible to damage such as rutting and pot holes. While for steel-concrete composite girders, the concrete deck is generally thick and heavy, and the deck is prone to cracking because of its low tensile strength and high creep. Thus, to improve the serviceability and durability of girders for long-span bridges, three new types of steel-UHPC lightweight composite bridge girders are proposed, where UHPC denotes ultra-high performance concrete. The first two types consist of an OSD and a thin UHPC layer while the third type consists of a steel beam and a UHPC waffle deck. Due to excellent mechanical behaviors and impressive durability of UHPC, the steel-UHPC composite girders have the advantages of light weight, high strength, low creep coefficient, low risk of cracking, and excellent durability, making them competitive alternatives for long-span bridges. To date, the proposed steel-UHPC composite girders have been applied to 14 real bridges in China. It is expected that the application of the new steel-UHPC composite girders on long-span bridges will have a promising future.

关键词: steel-UHPC composite bridge girder     long-span bridge     orthotropic steel deck     fatigue cracking     durability    

Structural performance of a façade precast concrete sandwich panel enabled by a bar-type basalt fiber-reinforced

《结构与土木工程前沿(英文)》 2023年 第17卷 第1期   页码 122-137 doi: 10.1007/s11709-022-0894-1

摘要: In this study, a novel diagonally inserted bar-type basalt fiber reinforced polymer (BFRP) connector was proposed, aiming to achieve both construction convenience and partially composite behavior in precast concrete sandwich panels (PCSPs). First, pull-out tests were conducted to evaluate the anchoring performance of the connector in concrete after exposure to different temperatures. Thereafter, direct shear tests were conducted to investigate the shear performance of the connector. After the test on the individual performance of the connector, five façade PCSP specimens with the bar-type BFRP connector were fabricated, and the out-of-plane flexural performance was tested under a uniformly distributed load. The investigating parameters included the panel length, opening condition, and boundary condition. The results obtained in this study primarily indicated that 1) the bar-type BFRP connector can achieve a reliable anchorage system in concrete; 2) the bar-type BFRP connector can offer sufficient stiffness and capacity to achieve a partially composite PCSP; 3) the boundary condition of the panel considerably influenced the out-of-plane flexural performance and composite action of the investigated façade PCSP.

关键词: precast concrete sandwich panel     basalt fiber reinforced polymer     pull-out performance     shear performance     out-of-plane flexural performance    

Effectiveness of state incentives for promoting wind energy: A panel data examination

Deepak SANGROYA,Jogendra NAYAK

《能源前沿(英文)》 2015年 第9卷 第3期   页码 247-258 doi: 10.1007/s11708-015-0364-8

摘要: Over the last decade, India has started to concentrate earnestly on renewable energy. The Indian government, as well as different state governments, are adopting policy instruments such as feed in tariff, captive consumption, renewable purchase obligation and generation based incentive etc. aimed at renewable energy development. This paper evaluates the effectiveness of state level incentives for the development of wind energy in India. Fixed effect panel data modelling technique of econometric analysis is used to analyse the data of 26 Indian states in 11 years. The results show that feed in tariff and captive consumption are the significant predictors of wind energy development. However, renewable purchase obligation does not affect wind energy significantly.

关键词: India     wind energy development     state incentives     econometric analysis     panel data    

On braced trapezoidal corrugated steel shear panels: An experimental and numerical study

《结构与土木工程前沿(英文)》 2023年 第17卷 第3期   页码 396-410 doi: 10.1007/s11709-023-0934-5

摘要: In this study, a new system consisting of a combination of braces and steel infill panels called the braced corrugated steel shear panel (BCSSP) is presented. To obtain the hysteretic behavior of the proposed system, the quasi-static cyclic performances of two experimental specimens were first evaluated. The finite element modeling method was then verified based on the obtained experimental results. Additional numerical evaluations were carried out to investigate the effects of different parameters on the system. Subsequently, a relationship was established to estimate the buckling shear strength of the system without considering residual stresses. The results obtained from the parametric study indicate that the corrugated steel shear panel (CSSP) with the specifications of a = 30 mm, t = 2 mm, and θ = 90° had the highest energy dissipation capacity and ultimate strength while the CSSP with the specifications of a = 30 mm, t = 2 mm, and θ = 30° had the highest initial stiffness. It can thus be concluded that the latter CSSP has the best structural performance and that increasing the number of corrugations, corrugation angle, and plate thickness and decreasing the sub-panel width generally enhance the performance of CSSPs in terms of the stability of their hysteretic behaviors.

关键词: trapezoidal corrugated plate     steel shear panel     braced steel shear panel     experimental study     buckling resistance.    

农作物秸秆人造板的研究

周定国

《中国工程科学》 2009年 第11卷 第10期   页码 115-121

摘要:

发展农作物秸秆人造板产业对于保护森林资源和人类环境,解决我国木材原料供应不足的矛盾具有重要的现实意义。近年来,科技人员在农作物秸秆人造板基础研究、产品开发和工业化应用方面做了大量的研究工作。文章介绍了笔者及所在团队在秸秆原料特性和秸秆板制造工艺方面的最新研究成果。

关键词: 农作物秸秆     人造板     研究前景    

The development of ultralightweight expanded perlite-based thermal insulation panel using alkali activator

Damla Nur ÇELİK; Gökhan DURMUŞ

《结构与土木工程前沿(英文)》 2022年 第16卷 第11期   页码 1486-1499 doi: 10.1007/s11709-022-0881-6

摘要: The International Energy Agency (IEA) states that global energy consumption will increase by 53% by 2030. Turkey has 70% of the world’s perlite reserves, and in order to reduce energy consumption a thermal insulation panel was developed in Turkey using different particle sizes of expanded perlite (EP). In this study, 0–1.18 mm (powder) and 0–3 mm (granular) EP particle sizes were selected, since they have the lowest thermal conductivity coefficients among all the particle sizes. In addition, an alkali activator solution was used as a binder in the mixtures. The alkaline activator solution was obtained by mixing sodium hydroxide solution (6, 8, 10, and 12 mol·L−1) and sodium silicate (Module 3) at the different ratios of Na2SiO3 to NaOH of 1, 1.5, 2, and 2.5. This study aimed to experimentally determine the optimum binder and distribution ratio of EP, with the lowest coefficient of thermal conductivity and the lowest density. The lowest thermal conductivity and the lowest density were determined as 0.04919 W·m−1·K−1 and 133.267 kg/m3, respectively, in the sample prepared with 83.33% powder-size EP, 6 mol·L−1 sodium hydroxide solution, and ratio of Na2SiO3 to NaOH of 1.5. The density, thermal conductivity, and compressive strength of the sample showed the same trends of behavior when the Na2SiO3 to NaOH ratio was increased. In addition, the highest compressive strength was measured in 12 mol·L−1 NaOH concentration regardless of particle size. In conclusion, the study predicts that the EP-based thermal insulation panel can be used as an insulation material in the construction industry according to the TS825 Thermal Insulation Standard.

关键词: expanded perlite     alkali activator     thermal insulation panel     thermal conductivity    

Lung function and air pollution exposure in adults with asthma in Beijing: a 2-year longitudinal panel

《医学前沿(英文)》 2022年 第16卷 第4期   页码 574-583 doi: 10.1007/s11684-021-0882-1

摘要: The effect of air pollution on the lung function of adults with asthma remains unclear to date. This study followed 112 patients with asthma at 3-month intervals for 2 years. The pollutant exposure of the participants was estimated using the inverse distance weight method. The participants were divided into three groups according to their lung function level at every visit. A linear mixed-effect model was applied to predict the change in lung function with each unit change in pollution concentration. Exposure to carbon monoxide (CO) and particles less than 2.5 micrometers in diameter (PM2.5) was negatively associated with large airway function in participants. In the severe group, exposure to chronic sulfur dioxide (SO2) was negatively associated with post-bronchodilator forced expiratory flow at 50%, between 25% and 75% of vital capacity % predicted (change of 95% CI per unit: −0.34 (−0.55, −0.12), −0.24 (−0.44, −0.03), respectively). In the mild group, the effect of SO2 on the small airways was similar to that in the severe group, and it was negatively associated with large airway function. Exposure to CO and PM2.5 was negatively associated with the large airway function of adults with asthma. The negative effects of SO2 were more evident and widely observed in adults with severe and mild asthma than in adults with moderate asthma. Patients with asthma react differently to air pollutants as evidenced by their lung function levels.

关键词: lung function     asthma     air pollution     adult    

Spillover effect of environmental investment: evidence from panel data at provincial level in China

Qunhui LIN, Guanyi CHEN, Wencui DU, Haipeng NIU

《环境科学与工程前沿(英文)》 2012年 第6卷 第3期   页码 412-420 doi: 10.1007/s11783-012-0392-0

摘要: This paper considers pollution density as a function of environmental investment. The higher environmental investment, the lower pollution density. The lower the pollution density is the higher production technology becomes. This is called the spillover effect. We collected China’s panel data at the provincial level from 2005 to 2009, and tested the spillover effect of environmental investment. This paper finds that the environmental investment influenced production technology positively. There is a significant positive relation between government expenditure and spillover effect.

关键词: environmental investment     spillover effect     endogenous growth    

A comprehensive simulator for assessing the reliability of a photovoltaic panel peak power tracking system

Nabil KAHOUL,Mourad HOUABES,Ammar NEÇAIBIA

《能源前沿(英文)》 2015年 第9卷 第2期   页码 170-179 doi: 10.1007/s11708-015-0353-y

摘要: When designing a maximum power point tracking (MPPT) algorithm, it is often difficult to correctly predict, before field testing, the behavior of this MPPT under varying solar irradiation on photovoltaic (PV) panels. A solution to this problem is to design a maximum power point trackers simulator of a PV system used to test MPPT algorithms. This simulator must have the same role as the MPPT card of the PV panel and thus will fully emulate the response of a real MPPT card of the PV panel. Therefore, it is a good substitute to help to test the peak power trackers of the PV system in the laboratory. This paper describes a simple peak power trackers simulator of the PV system which has a short response time thus, can be used to test MPPT algorithms under very rapid variation condition. The obtained results and the theoretical operation confirm the reliability and the superior performance of the proposed model.

关键词: photovoltaic module     DC-DC converter     design     maximum power point tracking (MPPT) card     microprocessor    

地铁客室通风板模型数值模拟及实验研究 Article

陶羽, 杨明智, 钱博森, 伍钒, 王田天

《工程(英文)》 2019年 第5卷 第2期   页码 329-336 doi: 10.1016/j.eng.2018.12.007

摘要:

列车客室内流场研究是轨道列车设计及优化中的关键一环。内流场特性对车内温度分布及乘客舒适性有着显著影响。针对内流场的实验研究可获得较准确的结果,但需要大量时间和经济成本。数值模拟相对于实验可在更短时间内获得内流场特性。本文采用两种简化模型(多孔介质模型和多孔阶跃面模型)来提升轨道列车客室内流场数值模拟的计算效率。将两种简化模型及原始模型的数值模拟结果与实验数据进行比较。结果表明,多孔介质模型的结果与原始模型结果以及实验数据吻合得较好,其流场特性参数(温度和速度)的数值误差较小,最大数值误差为4.71%。在原始模型和多孔介质模型的数值模拟结果中,同一参数之间的数值误差在1% 以内。采用多孔介质模型替代原始模型进行地铁列车客室内流场数值模拟,所占用的计算资源相应减少了25%,且其结果保持了很好的准确性。

关键词: 数值模拟     实验     通风板模型     地铁    

Field validation of UHPC layer in negative moment region of steel-concrete composite continuous girder

Minghong QIU; Xudong SHAO; Weiye HU; Yanping ZHU; Husam H. HUSSEIN; Yaobei HE; Qiongwei LIU

《结构与土木工程前沿(英文)》 2022年 第16卷 第6期   页码 744-761 doi: 10.1007/s11709-022-0843-z

摘要: Improving the cracking resistance of steel-normal concrete (NC) composite beams in the negative moment region is one of the main tasks in designing continuous composite beam (CCB) bridges due to the low tensile strength of the NC deck at pier supports. This study proposed an innovative structural configuration for the negative bending moment region in a steel-concrete CCB bridge with the aid of ultrahigh performance concrete (UHPC) layer. In order to investigate the feasibility and effectiveness of this new UHPC jointed structure in the negative bending moment region, field load testing was conducted on a newly built full-scale bridge. The newly designed structural configuration was described in detail regarding the structural characteristics (cracking resistance, economy, durability, and constructability). In the field investigation, strains on the surface of the concrete bridge deck, rebar, and steel beam in the negative bending moment region, as well as mid-span deflection, were measured under different load cases. Also, a finite element model for the four-span superstructure of the full-scale bridge was established and validated by the field test results. The simulated results in terms of strains and mid-span deflection showed moderate consistency with the test results. This field test and the finite element model results demonstrated that the new configuration with the UHPC layer provided an effective alternative for the negative bending moment region of the composite beam.

关键词: field test     steel-concrete composite beam     continuous girder bridge     negative bending moment region     ultrahigh performance concrete    

Flexural and longitudinal shear performance of precast lightweight steel–ultra-high performance concrete composite beam

《结构与土木工程前沿(英文)》 2023年 第17卷 第5期   页码 704-721 doi: 10.1007/s11709-023-0941-6

摘要: In this study, the flexural and longitudinal shear performances of two types of precast lightweight steel–ultra-high performance concrete (UHPC) composite beams are investigated, where a cluster UHPC slab (CUS) and a normal UHPC slab (NUS) are connected to a steel beam using headed studs through discontinuous shear pockets and full-length shear pockets, respectively. Results show that the longitudinal shear force of the CUS is greater than that of the NUS, whereas the interfacial slip of the former is smaller. Owing to its better integrity, the CUS exhibits greater flexural stiffness and a higher ultimate bearing capacity than the NUS. To further optimize the design parameters of the CUS, a parametric study is conducted to investigate their effects on the flexural and longitudinal shear performances. The square shear pocket is shown to be more applicable for the CUS, as the optimal spacing between two shear pockets is 650 mm. Moreover, a design method for transverse reinforcement is proposed; the transverse reinforcement is used to withstand the splitting force caused by studs in the shear pocket and prevent the UHPC slab from cracking. According to calculation results, the transverse reinforcement can be canceled when the compressive strength of UHPC is 150 MPa and the volume fraction of steel fiber exceeds 2.0%.

关键词: precast steel–UHPC composite beam     flexural performance     longitudinal shear performance     parametric study     transverse reinforcement ratio    

Direct energy rebound effect for road transportation in China

《工程管理前沿(英文)》   页码 597-611 doi: 10.1007/s42524-023-0276-y

摘要: The enhancement of energy efficiency stands as the principal avenue for attaining energy conservation and emissions reduction objectives within the realm of road transportation. Nevertheless, it is imperative to acknowledge that these objectives may, in part or in entirety, be offset by the phenomenon known as the energy rebound effect (ERE). To quantify the long-term EREs and short-term EREs specific to China’s road transportation, this study employed panel cointegration and panel error correction models, accounting for asymmetric price effects. The findings reveal the following: The long-term EREs observed in road passenger transportation and road freight transportation range from 13% to 25% and 14% to 48%, respectively; in contrast, the short-term EREs in road passenger transportation and road freight transportation span from 36% to 41% and 3.9% to 32%, respectively. It is noteworthy that the EREs associated with road passenger transportation and road freight transportation represent a partial rebound effect, falling short of reaching the magnitude of a counterproductive backfire effect. This leads to the inference that the upsurge in energy consumption within the road transportation sector cannot be solely attributed to advancements in energy efficiency. Instead, various factors, including income levels, the scale of commodity trade, and industrial structure, exert more substantial facilitating influences. Furthermore, the escalation of fuel prices fails to dampen the demand for energy services, whether in the domain of road passenger transportation or road freight transportation. In light of these conclusions, recommendations are proffered for the formulation of energy efficiency policies pertinent to road transportation.

关键词: road transportation     direct energy rebound effect     asymmetric price effects     panel data model    

标题 作者 时间 类型 操作

Construction management and technology innovation for main projects of Quanzhou Bay Bridge

Jun DU, Fangwen WENG

期刊论文

Precast steel–UHPC lightweight composite bridge for accelerated bridge construction

Shuwen DENG, Xudong SHAO, Xudong ZHAO, Yang WANG, Yan WANG

期刊论文

Innovative steel-UHPC composite bridge girders for long-span bridges

Xudong SHAO, Lu DENG, Junhui CAO

期刊论文

Structural performance of a façade precast concrete sandwich panel enabled by a bar-type basalt fiber-reinforced

期刊论文

Effectiveness of state incentives for promoting wind energy: A panel data examination

Deepak SANGROYA,Jogendra NAYAK

期刊论文

On braced trapezoidal corrugated steel shear panels: An experimental and numerical study

期刊论文

农作物秸秆人造板的研究

周定国

期刊论文

The development of ultralightweight expanded perlite-based thermal insulation panel using alkali activator

Damla Nur ÇELİK; Gökhan DURMUŞ

期刊论文

Lung function and air pollution exposure in adults with asthma in Beijing: a 2-year longitudinal panel

期刊论文

Spillover effect of environmental investment: evidence from panel data at provincial level in China

Qunhui LIN, Guanyi CHEN, Wencui DU, Haipeng NIU

期刊论文

A comprehensive simulator for assessing the reliability of a photovoltaic panel peak power tracking system

Nabil KAHOUL,Mourad HOUABES,Ammar NEÇAIBIA

期刊论文

地铁客室通风板模型数值模拟及实验研究

陶羽, 杨明智, 钱博森, 伍钒, 王田天

期刊论文

Field validation of UHPC layer in negative moment region of steel-concrete composite continuous girder

Minghong QIU; Xudong SHAO; Weiye HU; Yanping ZHU; Husam H. HUSSEIN; Yaobei HE; Qiongwei LIU

期刊论文

Flexural and longitudinal shear performance of precast lightweight steel–ultra-high performance concrete composite beam

期刊论文

Direct energy rebound effect for road transportation in China

期刊论文