Acceptance Tests For Surface Characteristics Of Steel Strands In Prestressed Concrete

This report provides practical tests to identify and measure residues (e.g., rust, lubricants used in manufacturing processes, or corrosion inhibitors) on the surface of steel prestressing strands and to establish thresholds for residue types found to affect the strength of the strand's bond to concrete. Key products presented here are four test methods suitable for use in a quality assurance program for the manufacture of steel prestressing strand.

This fib Recommendation gives technical guidelines regarding design, testing, acceptance, installation, qualification, inspection and maintenance of stay cable systems using prestressing steels (strands, wires or bars) as tensile elements, which can be applied internationally. This Recommendation is applicable for cable-stayed bridges and other suspended structures such as roofs. It may also be used for hangers in arch structures and as suspension cables, as appropriate. This Recommendations has been formulated by an international working group comprising more than 20 experts from administrative authorities, universities, laboratories, owners, structural designers, suppliers of prestressing steels and stay cable suppliers. The text has been written to cover best construction practices around the world, and to provide material specifications that are considered to be the most advanced available at the time of preparing this text. For ease of use (for client, designer and cable supplier), the complex content has been arranged thematically according to the system components into chapters focusing on performance characteristics, requirements and acceptance criteria. Requirements and comments have been specified for all parties involved in design and construction in order to aim for a uniform and high quality and durability. The interfaces to the structural designer are highlighted. The essential subjects are: Design and detailing of stay cables including saddles and damping devices Durability requirements and corrosion protection systems Requirements for the materials Testing requirements for the stay cables Installation, tolerances, qualification of companies and personnel Inspection, maintenance and repair. This Recommendation does not cover the technology of stay cables whose tensile elements are ropes, locked-coil cables, etc. or which consist of composite materials. Nevertheless, in many cases the specified performance criteria may also be applicable to these systems, although numerical values given for the acceptance criteria may need to be adjusted. For these systems it has been difficult to provide multiple protective layers similar to those specified for stay cables made from prestressing steel and therefore, the quality of corrosion protection may not be equivalent. While extradosed cables have similarities with stay cables, generally agreed design and system acceptance criteria are not yet available and therefore, this type of cable is not covered.

This is an open access book. This book focuses on the durability problems of existing prestressed concrete (PC) structures caused by strand corrosion, clarifies the mechanical behavior of corroded prestressing strands, corrosion-induced cracking, bond degradation, prestress loss and structural performance deterioration, and proposes the corresponding prediction models. Its aim is to provide the knowledge, tools, and methods to understand the deterioration phenomena of PC structures. We hope that this text may be useful for those who work in the field of civil engineering. It is suitable for teachers and students majoring in civil engineering in universities, and researchers in the field of civil engineering. It is also suitable for practitioners of design institutes, construction units, supervising units and traffic management departments.