Engineering Commons^™

Continuity Of Bridges Composed Of Simple-Span Precast Prestressed Concrete Girders Made Continuous, Libin Yin

Dissertations

Bridges composed of simple-span, precast, prestressed concrete girders made continuous via cast-in-place decks and diaphragms are continuous only for live loads and superimposed dead loads. The continuity diaphragms often crack due to time dependent effects in the girders. These cracks not only impair bridge ascetics and durability, but also reduce "degree of continuity". A related issue is that joint construction is time consuming and expensive due to reinforcement congestion. This dissertation presents a series of field tests, analytical studies, and laboratory experiments concerning the design and performance of this type of bridge.

Based on a survey of the state departments …

Performance Of Self-Compacting Concrete, Mohamed Samir Rushdy

Archived Theses and Dissertations

Concrete compaction is one of the indispensable fundamentals of concrete manufacturing. However, thorough compaction cannot always be insured. This can be wholly or partially encountered in congested sections, out-of reach deep foundations and narrow or irregular precast components. On the other hand, typical vibrators were considered as contributor to health hazards to workers. Self-compacting concrete (SCC) is an emerging concrete where the cohesive yet flowable consistency of the concrete itself secures adequate placement with high level of homogeneity and little or no segregation. Such concrete is primarily achieved by incorporating admixtures that is referred to as viscosity modifying (VM) admixtures …

Recycled Concrete Properties And Feasibility, Mourad Nabil Shenouda

Archived Theses and Dissertations

As conventional good quality aggregates are becoming scarce in some zones in Egypt and many areas worldwide, and as environmental concerns are raised on dumping old and fresh concrete in landfills, recycled concrete has been receiving increased interest worldwide for its potential environmental, economic and technical merits. In fact, many countries have adopted such concrete in their codes and the majority of their old concrete is being recycled. An attempt is being made to trigger factors and means that enhance the economic feasibility of recycled concrete. The overall goal of this work is to pinpoint strength and deficiencies in this …