毗河供水工程蒋铜渡槽高架空槽身现浇悬挂式贝雷梁支撑技术研究

本文对悬挂式贝雷梁支撑技术在毗河供水工程蒋铜渡槽高架空槽身现浇的应用实例进行了介绍和分析,对今后丘陵地区高架空渡槽槽身现浇支撑体系的选择提供借鉴和参考。

高层建筑间高架空大跨度天桥楼施工技术

高架空天桥楼出现后,如何保证其能按设计师们的蓝图建成而不出现施工质量、安全问题,是重要的施工技术。本文结合工程施工实例对天桥楼的施工与质量保证技术进行阐述。

毗河供水一期工程复杂地形条件下长距离输水渡槽设计

毗河供水一期工程蒋铜渡槽横跨三叉河及左右岸低洼浅丘地形,地面高程420m~460m,渡槽长度5552m,共跨越3个乡镇,最高架空高度50m,是目前中国单座已建渡槽长度之最,渡槽线路总体呈SE向,平面共布置9处转弯,跨越三叉河、金简路县道及多条乡道,其成功应用为平原及丘陵区引调水工程线路布置提供了借鉴经验。

Study on the Mechanical Properties of Irregular Curved Steel Box Girder for City Viaduct

This paper deeply analyses the influence of different local tectonic on stress performance of spatial curved steel box Girder Bridge, using the finite element analysis software to establish space finite element model of this bridge, calculation and analysis were made on the bridge of the strength, stiffness. It has certain reference value for guiding engineering design, have a good foundation for the mechanical properties and stability of linear and nonlinear further study of curved steel box girder.

Determining of the Real Condition of High-Voltage Overhead Power Lines

Significant investments have been made regarding the construction of a great number of high-voltage overhead power lines of all voltage levels, and now the questions arise on where and how to direct the investments necessary for the maintenance of overhead power lines. To organise the process of maintenance of overhead power lines correctly, it is necessary to have the current information on the condition of particular components of a line. In this paper, special attention has been paid to the real condition of overhead power lines, with the aim of making the decision whether some of the following measures are necessary, and to what extent： the revitalisation for a certain number of years is perceived, the revitalisation up to five years and reconstruction of the overhead power line is performed, its restoration is performed or nothing is done. The approach to the perceiving of real condition of high-voltage overhead power lines is presented on a global block diagram. With the aim of setting out the list of priorities for revitalisation, the criteria have been defined with regards to the real condition of particular components of an overhead power line, as well as pursuant to the role and importance in an electric power system. The correctly defined criteria contribute to the solving of the problem of making a single list of priorities for the revitalisation of high-voltage overhead power lines. In that way, the recommendations are being given to the transmission companies, to achieve a higher reliability of an electric power system, with a minimum number of cancellations and a maximum extension of working life of all the components of overhead power lines. A correct maintenance of overhead power lines brings large financial savings to the owners of transmission companies, and that is the primary goal in a deregulated environment.

Roof design of China Southern Airlines No.1 Hangar in Beijing Daxing International Airport

To overcome the limitations of structural height imposed by airspace restrictions in the design of maintenance hangar roofs with long spans,a new diagonal truss roof structural system is introduced for the first time.In the design of China Southern Airlines No.1 Hangar,4 main trusses were arranged diagonally along the depth direction,forming a W-shape truss.3 lineshaped trusses were arranged along the span direction,and double-layer space latticed structure is laid on them.The design optimized the height of the 183 m+222 m super long-span roof to 11.5 m,the maximum dimension the site could provide,so that the building height is within the permitted 40m.The steel consumption of the roof is only 165 kg/m^(2).The installation of diagonal trusses changed the unidirectional load transmission path of the roof and enhanced the spatial load transmission,effectively relieving the burden on the gate-side truss.This design enables the implementation of a maintenance hangar with a 222 m-span and heavy roof within the constraints of low airspace height.

Spatio-temporal framework of tectonic uplift stages of the Tibetan Plateau in Cenozoic

Four intensive uplift periods, i.e., 60–35, 25–17 and 12–8 Ma (but 18–13 Ma in the Himalayas of the southern Tibet), and since about 5 Ma, can be determined on the Tibetan Plateau by synthetical analysis of low-temperature thermo-chronology data, sedimentary deposit records, and structural deformation records of different areas. The strong tectonic uplift periods in different areas on the Tibetan Plateau are penecontemporaneous, except for the Himalayan area of the southern Tibet, where a rapid uplift and exhumation period, controlled by the activity of the South Tibetan Detachment System faults, occurred during 18–13 Ma. These strong uplift and exhumation periods correspond well to intensive deformation activity periods, suggesting tectonically-controlled uplift and exhumation. The deposit records, such as the distribution of coarse clastic sediments, the distribution of tectonically-controlled basins, stratigraphic discontinuousness or unconformity, and fault-controlled geomorphologic evolution, also match well with the strong uplift and exhumation periods. Expanding processes of the plateau are also discussed.

Vehicle height and leveling control of electronically controlled air suspension using mixed logical dynamical approach

Vehicle height and leveling control of electronically controlled air suspension(ECAS) still poses theoretical challenges for researchers that have not been adequately addressed in prior research. This paper investigates the design and verification of a new controller to adjust the vehicle height and to regulate the roll and pitch angles of the vehicle body(leveling control) during the height adjustment procedures. A nonlinear mechanism model of the vehicle height adjustment system is formulated to describe the dynamic behaviors of the system. By using mixed logical dynamical(MLD) approach, a novel control strategy is proposed to adjust the vehicle height by controlling the on-off statuses of the solenoid valves directly. On this basis, a correction algorithm is also designed to regulate the durations of the on-off statuses of the solenoid valves based on pulse width modulated(PWM) technology, thus the effective leveling control of the vehicle body can be guaranteed. Finally, simulations and vehicle tests results are presented to demonstrate the effectiveness and applicability of the proposed control methodology.