Here is helpful, actionable content regarding , structured for engineers, inspectors, and construction professionals. 1. Quick Reference: Crack Type vs. Cause vs. Severity | Crack Appearance | Most Likely Cause | Immediate Action | Long-term Concern | | :--- | :--- | :--- | :--- | | Longitudinal (Vertical) | Overstressing during prestressing, restraint shrinkage, or freezing of wet concrete | High : Calculate crack width. >0.2mm is serious. | Loss of prestress, corrosion of strands. | | Diagonal (45°) | Insufficient shear capacity, overloading, or differential settlement | Critical : Unload immediately. | Shear failure (brittle, sudden collapse). | | Horizontal at mid-height | Bending moment from lateral load (wind/earthquake) or handling damage | Moderate : Check eccentricity. | Reduced flexural strength. | | Hairline map/crazing | Rapid surface drying, high heat of hydration | Low : Monitor. | Usually cosmetic; no structural risk. | | Spiral/pop-out | Alkali-silica reaction (ASR) or freeze-thaw | Moderate : Test for ASR. | Progressive expansion, bar corrosion. | 2. Critical Engineering Checks for SP Columns Unlike conventional RC columns, SP columns rely on high-stresteel strands . A crack here can indicate strand relaxation or slippage.