基于Midas Civil的钢管—贝雷组合支架优化设计

高架桥由于离地面较高、施工周期长，往往采用支架法进行施工，常见的有满堂支架法和钢管-贝雷组合支架法两种形式。针对组合支架法施工缺乏科学准确的分析手段，根据传统经验采取过于保守的搭设方案这一问题，采用MidasCivil软件辅助建立模型和力学理论分析相结合的方法，得出钢管-贝雷组合支架搭设形式的优化办法。     

大型斜拉桥下横梁支架设计与施工

介绍忠县长江大桥主塔的下横梁支架设计和施工。大型斜拉桥的主塔下横梁一般较大且离承台顶面较高，本桥悬空高度69．5m，国内施工通常采用钢管桩或万能杆件支撑等落地式支架，本桥采用了悬空支架，利用塔柱预埋件焊接钢管桩斜撑作为支架。较通常落地式支架受力更明确、使用材料更少、工序更少、施工工期更短、成本大大降低，证明大型悬空支架的可行性．总结出相应的计算和施工方法。     

中承式钢管砼拱桥钢拱肋制作及安装方法

介绍钢管砼拱桥钢拱肋的制作方法以及利用扣索排架与扣索地锚安装钢管拱肋的无支架缆索安装方法,探索钢管砼拱桥施工方法新的技术领域,形成了大跨径钢管砼拱桥缆索吊装斜拉扣挂施工技术体系。     

丹江口汉江大桥下横梁支架施工结构分析

斜拉桥主塔下横梁施工是斜拉桥施工中重要的步骤,因此在施工中制定了有针对性的专项方案,采用钢管支架施工的方法,并对钢管支架加载以后的强度、刚度以及稳定性进行了验算,验算结果均在规范允许值范围之内,在最不利荷载作用下的关键截面产生的应力和变形满足结构的允许值,验证了该方案的可行性和安全性。     

现浇箱梁装配式超高支架施工质量控制

以重庆朝天门长江大桥引桥双层混凝土箱梁施工为例,从钢管格构柱为主的装配式支架的设计、施工入手,对超高支架施工的质量控制的关键环节进行分析,对保证箱梁现浇施工质量和安全具有重要意义.     

桥梁现浇箱梁中格构式钢管贝雷梁支架的施工技术

桥梁工程建设过程中,为节省地基处理面积,降低投入的施工设备数量,提高施工效率,一般会使用结构式钢管贝雷支架来进行施工。基于此,文章重点对桥梁现浇箱梁中结构式钢管贝雷架支梁的施工技术进行探讨。     

超宽箱梁0#块钢管支架设计与施工技术

在展开超宽箱梁施工时,所涉及到的临时结构类型较多,其中以钢管支架最为重要,在其作用下,可以为工程提供一个临时支撑系统,以便后续施工的顺利进行。文章以双湖路跨鸡啼门特大桥为背景,对其中的主桥0#箱梁施工展开探讨,探讨了钢管支架施工中需要注意的一些要点,提高了工程的整体质量。     

钢管格型构造柱在钢箱梁安装中的应用

某桥梁工程的主体为扭面钢箱梁结构,在现场拼装施工中以钢管格型构造柱为临时支架.结合本工程钢箱梁的安装工况分析钢管格型构造柱的受力状态,合理设计临时支架的钢管格型构造柱以保证其稳定性,利用微调小车控制钢箱梁的三维安装精度,可为类似工程提供借鉴和参考.     

钢管立柱贝雷支架在互通立交现浇箱梁中的应用

采用钢管柱和贝雷片作为支架是当前浇梁施工中应用比较广泛的支架施工方法,其具有安全质量可靠性高、承载能力强、经济效益好等诸多优点。文章以实际工程为例,对钢管立柱贝雷支架的基本构造以及对该方法的实际应用经验进行了分析讨论,工程施工后满足了施工要求,可为类似工程提供借鉴。     

南充西华体育公园车行桥现浇连续箱梁支架设计与施工

本文介绍了现浇连续箱梁采用贝雷桁架与碗扣式钢管组合成梁式支架,以保证在汛期能正常施工上部构造,对类似桥梁的施工具有一定的借鉴作用。     

风浪中螺旋桨水动力变化的实用计算方法

风浪中螺旋桨水动力变化规律是研究舰船在风浪中速航性能的重要方面。本文参照有关文献,提出了一种计算风浪中螺旋桨推力、转矩损失的实用定量计算方法,既可用于较精确地估算舰船在风浪中的增阻和失速,还可供提高舰船在风浪中速航性的研究和螺旋桨设计参考。     

港口集装箱起重机钢丝绳使用情况调查与分析

24个码头的 5 0 0多台集装箱起重机的钢丝绳使用情况表明 ,国内港口所用钢丝绳的品牌规格较多 ,其中日本产品和国内产品的市场占有率较高 ,国内产品的消耗量最大 ;进口产品的性能普遍较好 ,而国内产品则性能质量差异较大 ,除少数品牌外 ,使用寿命较短 ;各国内部品牌之间的价格接近 ,欧洲产品价格最高 ,国产品牌价格低廉     

Exploring the effects of passenger rail franchising in Britain: Evidence from the first two rounds of franchising (1997-2008)

This paper provides an up-to-date review of the previous literature concerning the impact of passenger rail franchising on productivity and costs in Britain, and also presents important new evidence. In particular, the extension in time of previously-used datasets offers the first opportunity to study the impacts of re-franchising. The previous literature emphasised the failure of franchising to produce sustained productivity gains, with a sharp deterioration in productivity after 2000. The new evidence presented offers a somewhat more positive view of the British experience. It suggests that part of what was previously considered to be falling productivity may in fact be due to exogenous changes in diesel prices. Further, new data suggests that the recent increases in costs have resulted in higher quality of service. Finally, competitive re-franchising, and the associated unwinding of short-term management and re-negotiated contracts, seems to have led to improvements in productivity between 2006 and 2008. Nevertheless, it remains the case that passenger rail franchising in Britain has failed to reduce costs in the way experienced in many other industries and in rail in other European countries. The evidence is that somewhat larger franchises, avoiding overlapping and optimising train density and length, should reduce costs. We also speculate that the major increase in wages and conditions of staff might be moderated by longer franchises, although that remains to be proved. This re-appraisal of the British case is important in the context of the wider international interest in the use of franchising in passenger rail, and its relevance to the current review of ways of introducing competition into the domestic rail passenger market in Europe.     

土工合成材料在堤坝工程中的应用

通过分析近年来土工合成材料在长江口深水航道、洋山港、太仓港、吕四港、宁波港、曹妃甸等具有代表性的堤坝工程中的应用情况,系统总结了土工合成材料在堤坝工程中的应用经验,可对同类工程有所借鉴.     

Decentralized Coastal Zone Management in Malaysia and Indonesia: A Comparative Perspective 1

Transferring decision-making process from central to local government and enhancing the role of local communities in managing coastal zones is an increasing commitment by governments in Southeast Asia. This article analyzes decentralized coastal zone management in two neighboring countries, Malaysia and Indonesia. The Federal system in Malaysia is argued to be able to influence more decentralized coastal zone management and to promote community-based management approaches. Meanwhile, the large diversity of coastal resources and communities combined with a still as yet tested decentralization policy in Indonesia is argued to bring more challenges in implementing the decentralization and community-based approaches in coastal zones. The lessons learned in this study provide insight in how far decentralized coastal zone management has taken place in Malaysia and Indonesia. The significant differences in the pattern of coastal zone management in these two countries are discussed in detail. This study recognizes that co-management and community-based approaches can be appropriate in dealing with coastal zone management. This comparative perspective is important to the development of a bigger picture of sustainable coastal zone management processes and cross-regional knowledge-sharing in Southeast Asia.     

A generalized model of pelagic biogeochemistry for the global ocean ecosystem. Part II: Numerical simulations

This paper presents a global ocean implementation of a multi-component model of marine pelagic biogeochemistry coupled on-line with an ocean general circulation model forced with climatological surface fields (PELAgic biogeochemistry for Global Ocean Simulations, PELAGOS). The final objective is the inclusion of this model as a component in an Earth System model for climate studies. The pelagic model is based on a functional stoichiometric representation of marine biogeochemical cycles and allows simulating the dynamics of C, N, P, Si, O and Fe taking into account the variation of their elemental ratios in the functional groups. The model also includes a parameterization of variable chlorophyll/carbon ratio in phytoplankton, carrying chl as a prognostic variable. The first part of the paper analyzes the contribution of non-local advective–diffusive terms and local vertical processes to the simulated chl distributions. The comparison of the three experiments shows that the mean chl distribution at higher latitudes is largely determined by mixing processes, while vertical advection controls the distribution in the equatorial upwelling regions. Horizontal advective and diffusive processes are necessary mechanisms for the shape of chl distribution in the sub-tropical Pacific. In the second part, the results have been compared with existing datasets of satellite-derived chlorophyll, surface nutrients, estimates of phytoplankton community composition and primary production data. The agreement is reasonable both in terms of the spatial distribution of annual means and of the seasonal variability in different dynamical oceanographic regions. Results indicate that some of the model biases in chl and surface nutrients distributions can be related to deficiencies in the simulation of physical processes such as advection and mixing. Other discrepancies are attributed to inadequate parameterizations of phytoplankton functional groups. The model has skill in reproducing the overall distribution of large and small phytoplankton but tends to underestimate diatoms in the northern higher latitudes and overestimate nanophytoplankton with respect to picoautotrophs in oligotrophic regions. The performance of the model is discussed in the context of its use in climate studies and an approach for improving the parameterization of functional groups in deterministic models is outlined.     

Exploring relationships between recruitment of European hake (Merluccius merluccius L. 1758) and environmental factors in the Ligurian Sea and the Strait of Sicily (Central Mediterranean)

This paper explores the relationships between the spatial patterns of the distribution of the young hakes of the year (YOY) and the oceanographical features in two areas of the Central Mediterranean (the Ligurian Sea and the Strait of Sicily), characterised by the occurrence of straits and channels. Comparative and correlative approaches were used to investigate coupling between biological and physical patterns. Density indices of the YOY were derived from annual trawl surveys from 1994 to 2004 in spring and autumn. Mean patterns of the YOY distributions were compared with the mesoscale oceanographical features reported in literature. No evident trends in recruitment strength were found in either areas. Inter-annual variability in YOY abundance in the Ligurian Sea was higher than in the Strait of Sicily. The location of nursery grounds in the study areas coincides with zones of relatively higher production, where upwelling and other enrichment processes regularly occur. The presence of predictable eddies and the frontal systems play a major role in the localization of nursery areas in the Strait of Sicily, maintaining their stable position throughout the years. The strongest transport of southern waters from the Tyrrhenian to the Ligurian Sea, due to the East Corsica Current, which is negatively correlated to winter North Atlantic Oscillation, is associated with the highest abundance of hake recruits in the nurseries of the Northern Ligurian Sea.     

Advances in the prediction of spudcan punch-through in double-layered soils

Punch-through failure of jack-up spudcan foundations occurs in active oil and gas drilling exploration regions, where relatively stiff soil overlies soft marine layer. Therefore, installation of spudcan foundations in such seabed formations threatens the stability of the jack-up rig. A site-specific assessment of the potential and severity of failure must be completed before the commencement of the installation. However, the accuracy of the prediction is limited by the validity of the design method currently in use. This paper presents advances in the prediction of punch-through failure of jack-up platforms in sand/stiff clay over soft clay soils. New analytical models for spudcan installation in double-layered soils are reviewed and compared to the existing methods in the ISO 19905-1 standard and SNAME standard. The capabilities and limitations of each method are summarised and recommendations are drawn for the theoretical predictions of spudcan punch-through in double-layered soils.     

长江口北支崇启大桥处潮位和盐度过程研究

位于长江口北支的崇启大桥处于盐淡水交替区,其混凝土桥墩易受海水腐蚀。为给桥墩抗腐试验提供必要的潮位变动区范围和盐度试验参数,建立了基于无结构网格的长江口盐水数值模型,计算分析了在不同径流量和外海潮汐边界条件下,崇启大桥断面潮位变幅及盐度变动过程。研究表明崇启大桥处潮位变幅大,潮汐是控制崇启大桥处水位变动范围的关键因素;桥墩处盐度整体取决于入海径流量,流量增加促使盐度降低,反之亦然;潮汐作用促使桥墩处呈现短周期性振荡盐度,盐度范围为10‰～26‰,其中枯季盐度平稳,洪季变幅大。     

An analysis of trends in passenger and freight transport energy consumption in India

This primary objective of this paper is to examine the causes for the change in energy consumption in the transport sector in India. The pattern of energy consumption and their causes for change are benchmarked against select countries. A mathematical model that decomposes changes in energy consumption to various factors has been used. The changes in the energy consumption are attributed to growth in transport volume, structural change or modal shift, and energy intensity. The analysis is conducted for passenger and freight transport separately. Results indicate that the growth in transport volume has been the main cause for increase in energy consumption for both passenger and freight transport in India despite the decline in energy intensity of various transport modes. Though not surprising for a growing economy like India, this poses a challenge for the future. Currently, India is a low carbon economy.