浅谈抱箍法在高林台河2号大桥盖梁施工中的应用

桥梁无支架施工在当前高速公路工程建设中越来越显示出其优越性,特别是在地势起伏较大、盖梁下面地质情况较差的情况下更是适宜的施工方法。抱箍法是无支架施工的一种新方法,其特点是投入小,施工方便,目前已成为桥梁盖梁施工的首选方案,应用也越来越广泛。     

Planning and control of paratransit services in Hong Kong

As paratransit services, Hong Kong's taxis and public light buses (PLB) carried some 30% of the 9.7 million daily public transport boardings in Hong Kong in 1988. Most of the vehicles are individually owned, and services are operated as commercially viable concerns. While operators have a high degree of operational flexibility, taxis and PLBs are closely regulated by the Government. The fleet sizes are controlled by licensing. There is a system of zoning for taxis, and operational prohibitions and restrictions for PLBs. Over the years, Hong Kong has developed some practicable means of operational control on taxis and PLBs. It has been 20 years since PLBs were legalized in 1969. The transition experienced by this mode, from no control to regulated operations, signifies a major step forward from the point of view of transport administration. The Government's participation in the planning for PLB services has guided the development of this mode. In this paper, the planning and control mechanisms for Hong Kong's paratransit modes are introduced. Identified deficiencies are also discussed.     

Research review of air traffic management

As air transport demand keeps growing more quickly than system capacity, efficient and effective management of system capacity becomes essential to the operation of the future global air traffic system. Although research in the past two decades has made significant progress in relevant research fields, e.g. air traffic flow management and airport capacity modelling, research loopholes in air traffic management still exist and links between different research areas are required to enhance the system performance of air traffic management. Hence, the objective of this paper is to review systematically current research in the literature about the issue of air traffic management to prioritize productive research areas. Papers about air traffic management are discussed and categorized into two levels: system and airport. The system level of air transport research includes two main topics: air traffic flow management and airspace research. On the airport level, research topics are: airport capacity, airport facility utilization, aircraft operations in the airport terminal manoeuvring area as well as aircraft ground operations research. Potential research interests to focus on in the future are the integration between airspace capacity and airport capacity, the establishment of airport information systems to use airport capacity better, and the improvement in flight schedule planning to improve the reliability of schedule implementation.     

Deregulating the bus industry in Britain: a reply

In the last four years, some 20 urban areas in the UK have commissioned or considered conducting Integrated Transport Studies, which are designed to develop a transport strategy for the next 20–30 years. Such studies represent a new approach to transport policy formulation, since they respond to a vision of the future for the area, treat a wide range of transport and land use policy instruments, emphasize synergy between those instruments, and provide a framework for facilitating action rather than a rigid blueprint for the future. They also differ from past studies in the speed with which they have been conducted, and in the analytical techniques which have made this possible. This paper reviews the background to these studies, the evaluation approach adopted, the policy instruments considered and the analytical methods developed for the studies. It concludes with an assessment of the policy implications stressing in particular the need to reduce trip length, the crucial impact of pricing as an instrument of transport policy, the importance of achieving synergy in strategy development, and the requirement for a common basis for evaluating and financing different transport policy instruments.     

Nigerian railways: problems and prospects

The very special topography of Greece with the hundreds of mainland and island ports generates vast possibilities for developing routing networks to link the ports to each other while satisfying total demand. An algorithm which minimizes total operating costs (fixed and variable) has been adapted and used to determine an optimal network solution. The total operating costs of this solution is compared to the total operating costs of the existing (1964 data) network and the optimal networks when fixed and variable costs are minimized independently. It is found that the actual network follows the minimal total operating costs solution quite closely.     

Book reviews

TRANSPORT AND REURBANISATION, by Leo H. Klaassen, Jan A. Bourdrez and Jacques Volmuller. Gower Press, England, 1981. 214 pp.

TRANSPORT AND PUBLIC POLICY PLANNING, edited by David Banister and Peter Hall. Mansell Publishing Ltd., London, 1981. 455 pp.

ACCESS FOR ALL by K. H. Schaeffer and Elliott Sclar. Columbia University Press, 1982. 182 pp.

ENVIRONMENTAL ANALYSIS OF TRANSPORTATION SYSTEMS, by Louis F. Cohn and Gary R. McVoy. John Wiley, 1982. 374 pp. (£35.00).

THE ECONOMICS OF URBAN FREIGHT TRANSPORT, by K. J. Button and A. D. Pearman. The MacMillan Press Ltd., London. 218 pp. (£20.00).

TRANSPORTATION MARKINGS, BY Brian Clearman. University Press of America, 1981. 459 pp.

REGULATION AND POLICIES OF AMERICAN SHIPPING, by Ernst G. Frankel, Auburn House Publishing Co., Boston, Massachusetts. 321 pp. ($24.95)     

Land use pressures on coastal estuaries in Atlantic Canada

Abstract

The management of estuarine areas in Canada has received little attention; this is specifically the case along the Atlantic coast. This article reviews the importance of estuaries as resources and analyzes the land‐use pressures which can affect them. Specific emphasis is placed on the results of a recent study of estuaries in Atlantic Canada. The incidence of the closures of shellfish areas is used as a measure of the impact of land development on estuaries.     

Maritime commercial malpractices and piracy under international law

The term ‘Piracy’ tends to be used in a loose, popular sense to refer to various acts of violence or lawlessness at sea which are not, strictly speaking, acts of piracy in law. In this article, the author examines the concept of piracy under international law and related notions such as hijacking and mutiny. In this context, he shows that the ‘malpractices’ of robber bands in such places as the inshore waters of Nigeria and The Philippines are not acts of piracy jure gentium.     

The role of habit and residential location in travel behavior change programs,a field experiment

Transportation - Early evaluations of travel change programs demonstrated dramatic success in shifting people out of cars and into transit and active travel. Yet methodological shortcomings of...