Shear Strength of Reinforced Concrete Columns with External Post-Tensioned Clamps
Bibliographic record
Abstract
An alternative method to retrofit reinforced concrete (RC) columns with insufficient shear reinforcement is investigated.The retrofit involves external prestressing of the columns in the transverse direction to increase both shear strength and drift capacity.External post-tensioned clamps, consisting of high-strength steel rods connecting a set of steel angles, were applied around the columns at different spacings and initial post-tensioning stresses.The tension induced in the steel rods exerts lateral confining pressure on the column by bearing of the angles against the corners of the column.Ten RC columns furnished with external post-tensioned clamps were tested under cyclic loads and approximately constant axial loads.In addition, six RC beams with clamps were tested under monotonically increasing loads.Both the column and beam specimens were fabricated with no transverse reinforcement in the form of conventional steel ties.Therefore, the external clamps were the only source of reinforcement resisting shear.The lateral prestress provided by the clamps was observed to increase the shear stress at the formation of the first inclined crack and at failure.As a result, the mode of failure of columns vulnerable in shear changed from shear failure to a more ductile failure dominated by flexure.The observed increase in shear strength is dependent on the lateral prestress and the tensile strength of the concrete.A simple equation, based on the mechanics of materials, is presented to calculate the shear strength of RC columns with external prestressing.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.008 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".