prestressed concrete

3 – P/S Tech CES 4711/5715 – Prestressed Concrete Garber 1

Homework 3 (group assignment for CES 4711; individual for CES 5715)

Problem 1 – Prestressing Process

Describe the prestressing process, differentiating between pre- and post-tensioning. Use figures as required. Keep the total response to less than 3 pages.

Problem 2 – Minimizing End Region Stress

(a) Discuss and illustrate the three methods for minimizing end region stress and maximizing mid-span capacity in pretensioned girders.

(b) Calculate the moment capacity and end region stress for the two sections shown below using the equations given in class.

(c) Comment on the results of calculations in (b) as it relates to harping of strands.

Problem 3 – Post-Tensioning

Describe and illustrate the different components of a post-tensioning system (maximum 3 pages). Include a short discussion on curved U-beams (from the PCI State-of-the-Art report). Use notes from class, VSL manual on PT (attached), PCI State of the Art Report (attached), or any other resource you find (cite your sources).

Section 1 Section 2 Properties for Both Sections

40% of strands debonded

0% of strands debonded

3 – P/S Tech CES 4711/5715 – Prestressed Concrete Garber 2

Rubric for Grading Homework

Category Possible Points

Demonstrated conceptual knowledge

3 2 1 0 The student has strongly demonstrated that they understand the concept(s) that they were tasked to write about.

The student has demonstrated to an average degree that they understand the concept(s) that they were tasked to write about.

The student has demonstrated to some extent that they understand the concept(s) that they were tasked to write about.

The student has not shown that they understand the concept(s) they were tasked to write about.

Quality of support / explanation / correctness of calculations

3 2 1 0 The student has provided sufficient evidence for their answer and clearly articulated / illustrated ideas, concepts, or processes. No errors or one small math error in calculations.

The student has provided sufficient evidence for their answer, but quality could have been improved. Or no illustrations provided. Or several errors in calculations presented.

The student has provided some evidence for their answer, but quality of articulation / illustration ideas, concepts, or processes could have been greatly improved.

Support / explanation could not be easily followed.

All aspects or parts of question addressed

2 1.33 0.67 0 The student has responded fully to the prompt and answered every part of the questions.

One aspect of prompts was not addressed.

Multiple aspects of the prompts were not answered.

No aspects of the prompts were answered.

Spelling and grammar

1 0.67 0.33 0 The student has proofread and shown an attempt to boost their professional ethos by addressing grammatical and mechanical issues.

The student may have proofread the document, but several spelling/grammar issues still present.

Numerous spelling/grammar issues.

Document was difficult to read and understand due to spelling/grammar.

Documentation and sources

1 0.67 0.33 0 The student has cited sources according to the given documentation standards.

In-text citations and works cited section were provided, but inconsistent/incomplete format.

No in-text citations or no works cited section provided.

No in-text citations and no works cited section provided.

Total 10

Turn-It-In Score reductions: 50-75% (-6), >75% (-10) (if clear signs of copied sections) Deduction for not including a problem: CES 4711/5711 – P1 (-3), P2 (-4), P3 (-3)