Design of Precast, Prestressed Bridge Girders Made Continuous


Book Description

This report documents and presents results of a study to determine time-dependent behavior and relevant design criteria for simple-span precast, prestressed bridge girders made continuous. A questionnaire was used to determine current practice. Creep and shrinkage tests of steam-cured concrete loaded at an early age were made. Computer simulations were used to investigate the effects of time-dependent material behavior and variation in design parameters on the effective continuity for live load plus impact. The findings suggest that positive moment connections in the diaphragms at the piers are not required and provide no structural advantages. The findings also suggest that effective continuity for live load plus impact can vary from 0 to 100% dependent on the design parameters and timing of construction. Computer analyses were also used to determine an upper limit for the amount of negative moment reinforcement over the supports to insure full moment redistribution and attainment of maximum bridge strength. New computer programs were developed for simplified analysis to determine time-dependent effects and service moments. Recommendations for design procedures were presented and design examples given.




Connection of Simple-span Precast Concrete Girders for Continuity


Book Description

Introduction and Research Approach -- Findings -- Interpretation, Appraisal, and Application -- Interpretation, Appraisal, and Application -- References -- Appendixes.




Precast concrete bridge continuity over piers


Book Description

Concrete bridges are an important part of today's road infrastructure. An important part of those concrete bridges is to a large extent prefabricated. Precast concrete enables all the advantages of an industrialized process to be fully utilized. Contemporary concrete mixtures are used to realize high-strength bridge girders and piers that exactly meet the requirements set, both structurally and aesthetically, with a small ecological footprint. Sustainable and durable! On the construction site, there is no need for complex formwork, the execution time is drastically reduced and where road, water and rail traffic on or under the bridge has to be temporarily interrupted, it is only minimally inconvenienced during the execution of the project. There is a wide variety of prefabricated bridges. In 2004, the fib commission on prefabrication already published the Bulletin 29 Precast concrete bridges which, in addition to the history of prefabricated bridges, also gave an overview of the different bridge types and structural systems. This document elaborates on one specific structural system: the continuous bridge. Task Group 6.5 "Precast concrete bridges" discusses in detail how to achieve continuity over the piers with precast elements. This bulletin bundles the experiences of experts in the field of bridge design so that less experienced designers would be able to identify the points of attention and make a correct design. In addition to the theoretical considerations, the principles are tested against three realizations in the USA and Europe. Commission 6 thanks the Co-Conveners Maher Tadros and Hugo Corres and all active members of the Task Group for sharing their knowledge and experience and for the successful realization of this bulletin.




Methods for Increasing Live Load Capacity of Existing Highway Bridges


Book Description

This synthesis will be of interest to state department of transportation bridge design and structural engineers, bridge consultants, and others involved in applied and research methods for increasing the live load capacity of existing highway bridges. The synthesis describes the current state of the practice for the various methods used to increase the live load capacity of existing highway bridges. This is done predominantly for bridges in the short- to medium-span range. Information on the more common bridge material types is presented. There is an emphasis on superstructure rather than substructure strengthening.




Continuous and Integral Bridges


Book Description

This book contains the invited contributions to the 1993 Henderson Colloquium organised by the British Group of IABSE (International Association for Bridge and Structural Engineering). It provides an international review of new techniques of designing and constructing joint-free bridges - an approach which is rapidly being developed and used in man




Theory and Design of Bridges


Book Description

Indeed, this essential working reference for practicing civil engineers uniquely reflects today's gradual transition from allowable stress design to Load and Resistance Factor Design by presenting LRFD specifications - developed from research requested by AASH-TO and initiated by the NCHRP - which spell out new provisions in areas ranging from load models and load factors to bridge substructure elements and foundations.







Conceptual Design of Precast Concrete Bridge Superstructures


Book Description

Concrete bridges are an important part of today's road infrastructure. An important part of those concrete bridges is to a large extent prefabricated. Precast concrete enables all the advantages of an industrialized process to be fully utilized. Contemporary concrete mixtures are used to realize high-strength bridge girders and piers that exactly meet the requirements set, both structurally and aesthetically, with a small ecological footprint. Sustainable and durable! On the construction site, there is no need for complex formwork, the execution time is drastically reduced and where road, water and rail traffic on or under the bridge has to be temporarily interrupted, it is only minimally inconvenienced during the execution of the project. Bridges capture the imagination. In addition to their pure functionality, overcoming a height difference, they offer designers unprecedented opportunities to shape their creativity, including when using precast concrete. This bulletin, prepared by the experts of Task Group 6.5 'Precast concrete bridges', takes a closer look at the conceptual (preliminary) design of prefabricated concrete bridges. The bulletin does not have the ambition to define the umbrella term 'conceptual design' but shows in a pragmatic way, using 24 examples spread all over the world, how leading designers use this methodology to select from the many possibilities to arrive at an ideal solution taking into account all design conditions. One often reads that experience is a necessary condition for good conceptual design. The pooled knowledge and experience in this bulletin already provide the reader with a good head start. Commission 6 thanks the former convener of the Task Group Hugo Corres, editor of this document, and the current co-conveners Marcello Waimberg and Ken-ichi Kata as well as all active members of the Task Group for sharing their knowledge and experience and for the successful realization of this bulletin.




Prestress Losses in Pretensioned High-strength Concrete Bridge Girders


Book Description

"The HCM includes three printed volumes (Volumes 1-3) that can be purchased from the Transportation Research Board in print and electronic formats. Volume 4 is a free online resource that supports the rest of the manual. It includes: Supplemental chapters 25-38, providing additional details of the methodologies described in the Volume 1-3 chapters, example problems, and other resources; A technical reference library providing access to a significant portion of the research supporting HCM methods; Two applications guides demonstrating how the HCM can be applied to planning-level analysis and a variety of traffic operations applications; Interpretations, updates, and errata for the HCM (as they are developed);A discussion forum allowing HCM users to ask questions and collaborate on HCM-related matters; and Notifications of chapter updates, active discussions, and more via an optional e-mail notification feature."--Publisher.




Bridge Design for Economy and Durability


Book Description

Describes several bridging concepts, which were developed and successfully applied during the author's forty years of close involvement with UK and international bridge design, construction, maintenance and research. The concepts mainly apply to the small/medium span range of bridges and viaducts.