PCI eLearning Course T130: Flexural Design of Precast, Prestressed Concrete—Strength Limit States-Bridge Design Manual, 3rd Edition

Bridge Design Manual, 3rd Edition

Pdf Summary

The document outlines comprehensive processes and standards for the design, manufacture, inspection, certification, and installation of precast, prestressed concrete bridge components. Key areas covered include:<br /><br />### Materials and Components<br />- **Concrete**: Requires the use of fine and coarse aggregates, water, cement, and chemical admixtures to improve workability and durability.<br />- **Prestressing Steel**: Incorporates pretensioning and post-tensioning methods, essential for structural integrity.<br />- **Nonprestressed Reinforcement**: Offers additional strength and is strategically placed to avoid interfering with prestressing steel.<br /><br />### Fabrication Process<br />- **Forms and Headers**: Typically fabricated from steel for precision and reuse. Detailed prestressing procedures using abutment-type or strutted beds are employed.<br />- **Concrete Batching and Mixing**: Achieved using central mixers to ensure consistency. <br />- **Curing**: Accelerated curing methods such as steam or electric heaters are used.<br />- **Product Removal**: Involves careful sequencing to prevent damage.<br /><br />### In-Plant and Jobsite Handling<br />- Equipment such as travel lifts or forklifts handle products. Proper rigging techniques ensure load distribution during handling and installation.<br /><br />### Quality Control<br />- **Inspection**: Continuous monitoring of concrete temperature during curing.<br />- **Product Evaluation and Repair**: Addressing minor defects to meet stringent tolerance requirements.<br /><br />### Bridge Load and Design Considerations<br />- **Load Characterization**: Considers permanent loads (dead loads, superimposed dead loads), live loads (HL-93 vehicular loads), and additional external forces.<br />- **Load Distribution**: Uses simplified and refined methods to account for beam configurations and skew corrections.<br /><br />### Specific Bridge Design Example<br />- A single-span bridge with AASHTO-PCI BT-72 beams and a composite cast-in-place deck is analyzed.<br />- **Shear and Moment Analysis**: Detailed calculations for shear forces, bending moments, and deflections.<br />- **Prestress Losses and Concrete Stresses**: Assessment of losses during various stages and compliance with AASHTO LRFD guidelines.<br /><br />### Certification Programs<br />- **PCI Certification**: Ensures plants and personnel adhere to quality control procedures.<br />- **State-Specific Specifications**: Nebraska and Washington DOT's respective standards for production, inspection, curing, and handling of concrete units.<br /><br />### Case Studies and Practice Survey<br />- Future research needs and case studies reflect on the effectiveness of integral bridge designs, emphasizing substructure flexibility and load accommodation.<br /><br />### Summary<br />The document meticulously details the engineering processes for creating durable prestressed concrete bridge components, addressing materials, fabrication, quality control, load distribution, and implementation of certification programs, ensuring structural safety and longevity.

Keywords

precast concrete

prestressed concrete

bridge components

fabrication process

quality control

load distribution

prestressing steel

certification programs

shear and moment analysis

concrete curing