JE Gumbel Giám đốc kỹ thuật quốc tế, công nghệ Insituform SYNOPSIS hiện các phương pháp thiết kế cho cả hai áp lực và lót không áp dụng các khái niệm đơn giản giới thiệu hơn 15 năm trước, khi các kỹ thuật đổi mới bằng cách sử dụng nhựa đường ống và các thành phần vẫn còn trong trứng nước. Trong khi những khái niệm này đã phục vụ một mục đích hữu ích trong việc cung cấp một cơ sở chấp nhận rộng rãi cho sự tăng trưởng của ngành công nghiệp cho đến nay, họ đang ngày càng. | STRUCTURAL DESIGN OF PIPE LININGS 1998 - REVIEW OF PRINCIPLES PRACTICE AND CURRENT DEVELOPMENTS WORLDWIDE J E Gumbel International Technical Director Insituform Technologies SYNOPSIS Current design methodologies for both non-pressure and pressure linings apply simple concepts introduced 15 or more years ago when renovation techniques using plastics pipes and components were still in their infancy. While these concepts have served a useful purpose in providing a widely accepted basis for growth of the industry hitherto they are increasingly recognised as too conservative or too imprecise for the full range of applications of today s more highly engineered pipe lining products. This paper reviews the principles underlying current methods of lining design including those practiced in the Australasian region and introduces new concepts of structural classification and analysis which are the subject of much discussion in the US and Europe and proving influential in shaping the next generation of design standards at both national and international level. The scope of current research activity in various countries is also briefly described. INTRODUCTION - HISTORICAL DEVELOPMENT The origins of current design concepts for pipe linings can be traced back to the earliest developments of the various classes of rehabilitation techniques using plastics pipes and components as illustrated in Fig 1. The technique of sliplining using continuous or discrete loose-fitting pipes Fig 1a dates back to the 1960 s. Such pipes are clearly independent of their host and are designed accordingly. Their internal pressure rating is based on long-term burst pressures derived from tests on pipes without any external radial support. Resistance of the liner pipe to external pressure is provided by the ring bending stiffness Sf defined as Sf EI D3 1 where E short-term flexural modulus I second moment of area t3 12 for solid-wall pipe of thickness t D median diameter of liner pipe outside diameter .
