1. Introduction

There are times when engineers would have to design and evaluate bridge structures that fall outside of the AASHTO design guideline. Therefore, when do we define a structure as irregular? How is evaluating an irregular bridge different from evaluating a regular bridge? How to minimize errors during the construction of irregular bridges? We invited midas expert Percy Penafiel, Professional Engineer Specialist from Nevada Department of Transportation, to answer some of the frequently asked questions from our users regarding evaluating irregular bridge structures. 

In the design project to replace the old Fulton Road arch bridge in Cleveland, OH, Michael Baker Intl engineer Daniel Baxter and his team has designed a 1,568-foot-long replacement structure for the original arch bridge, which retains the original design of six 210-foot-long concrete deck arch spans. For the replacement bridge structure, a precast, post-tensioned concrete arch bridge design was selected. You may be asking yourself, why post-tensioning the arch bridge? Arches usually provide sufficient stabilities to structures and it is not usual for bridge designers to post-tension such structures. In this tip, Daniel Baxter talks about why his team has decided to post-tension the arch bridge and how they have utilized construction stage analysis to design the post-tension process. 

How to Perform Time-dependent Analysis?

Mainly there are two ways to perform the time-dependent analysis. One is the time-step analysis and the other is the age-adjusted method.

Table of Contents

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A complex bridge is one of the most common engineering projects nowadays. This category of structures includes movable, cable-stayed, segmental concrete, and other bridges with unusual characteristics. These types of structures will require specialized expertise to design and build. One of our Expert Engineers, Yazeed Abuhassan, a Structural Design Engineer from Bergmann PC, shared his tips about designing a complex bridge.

One tip that could be useful to many is how he usually model the deck as an eccentric deck plate for moving load distribution purposes (creating an influence surface) without having to perform a beam/deck plate cut diagram to view the true moments in the composite girders.