Forensic report blames long-term structural degradation for Jet Set collapse

Court-appointed engineers say defects in construction and progressive deterioration of post-tensioning wires caused the April 2025 Jet Set nightclub collapse in Santo Domingo, which killed more than 200 people and injured hundreds. The report was formally filed in May 2026 and points to hidden internal damage that visual inspections would not have detected. Why it matters: - The findings could reshape how aging post-tensioned concrete buildings are inspected, repaired and regulated. - The report says conventional visual checks may miss hidden structural risks that can lead to catastrophic failure. - The case has broad implications for building safety in older structures in the Dominican Republic and beyond. What happened: - Court-appointed forensic engineers formally submitted an independent report on the Jet Set nightclub collapse in Santo Domingo. - The collapse occurred on April 8, 2025, and killed more than 200 people while leaving hundreds injured. - The report was presented to the First Court of Instruction of the National District on May 14, 2026, in case file No. 2025-0150267. - The judicial process remains ongoing. The details: - The investigation was led by Gabriel Carrera, PE, of Wiss, Janney, Elstner Associates; Alfonso Ibárreta, Ph.D., PE, CFEI, of Exponent; and José Lockhart, M.Sc., PE, of Structures & Inspections Engineering, PC. - The team included more than 25 engineers, chemists, metallurgists and materials scientists. - The report concludes, to the highest technical degree of probability, that the collapse resulted from the combined effect of construction defects and progressive deterioration of the post-tensioning tendons. - The building was constructed in 1973 and had been in operation for more than 50 years. - Ground-penetrating radar identified at least one beam with a misplaced post-tensioning duct, leaving that structural element significantly weaker than intended. - Laboratory evaluation found progressive deterioration of post-tensioning wires caused by hydrogen-assisted cracking, which weakens wire strength over time. - The report says both the construction defects and the ongoing deterioration were internal to the beams and would not have been identifiable by visual inspection. - Leveling material layers found on the roof indicate the beams were deflecting progressively over time, consistent with long-term structural weakening. - The report states the loads on the structure at the time of collapse were insufficient to cause a global failure in a properly built, undamaged structure, ruling out overload as the immediate cause. Between the lines: - The report points to a failure mode that developed over decades, not an abrupt event. - That makes the collapse a warning about hidden deterioration in older reinforced concrete buildings, especially where post-tensioning systems are involved. - The findings also suggest that reliance on surface-level inspections alone can leave major risks undetected. - Gabriel Carrera said the most significant contributors were internal to the structural elements and not visible from the outside. What’s next: - The report has been made public in the interest of transparency and technical discussion. - The forensic findings will likely remain central to the court case and any future scrutiny of building safety oversight. - Engineers and regulators may use the report to reassess inspection methods for aging structures with post-tensioned concrete systems. - Official documents were listed in the release. The bottom line: - The Jet Set collapse was not presented as a simple overload failure, but as the result of hidden construction defects and long-term structural deterioration that built up over decades.