Mumbai, March 25 -- Reliance Infrastructure-Astaldi Joint Venture (RAJV), the infrastructure firm constructing substantial portions of the Metro 4 corridor, was squarely responsible for the accident in Mulund on February 14, when a precast parapet segment fell on an autorickshaw and a car beneath, killing one person and injuring three others, a probe by the Mumbai Metropolitan Region Development Authority (MMRDA) has found. The probe report, submitted by Director (Projects) at MMRDA Basavraj M Bhadragond to MMRDA Commissioner Sanjay Mukherjee last week, blamed RAJV on several grounds, including taking shortcuts, resorting to unsafe behaviour, and ignorance of duty by the welder, the site supervisor, and the engineer. It held the contractor, the welder, the site supervisor, the site engineer and the project manager responsible for the incident. According to the report, which HT has accessed, when such precast segments are used for construction of elevated road/ rail carriageways, they must be secured with temporary metal fasteners; and the fasteners must be removed only after the segments have been 'stitched' to the carriageway using construction adhesive. At Mulund, the 6 feet x 4 feet parapet segment weighing 1.8 tonne was erected on the carriageway and secured in place with temporary fasteners on the night of February 13. The next day, however, the fasteners were "inadvertently" cut off by the welder even though the segment had not been stitched to the carriageway, the probe found. "On February 14, the engineer instructed the site supervisor to assign to the welder the task of cutting the hook of casted stitched parapets only.The welder cut the parapet's hook without ensuring proper stitching and support and without informing the concerned supervisor. This caused the 1.8-tonne parapet to become unstable and fall onto the road," the report said. The MMRDA did not find any lacunae in the precast parapet segment's technical parameters such as structural design, material and workmanship. But it identified several procedural and supervisory lapses - such as the contractor did not conduct a joint inspection or checklist confirming the readiness for removal of temporary support for parapet segments; no written authorisation was available prior to support removal; support removal activity proceeded without an approved method statement, though one was available; and no marking system existed to distinguish structurally completed segments from incomplete ones. RAJV secured the contract for constructing significant portions of the Metro 4 corridor including the Mulund stretch in June 2018. Though the MMRDA bypassed the firm in May 2022 and gave the remaining work to subcontractor Milan Road Buildtech on account of delays, RAJV remained the contractor on record. Shortly after the incident on February 14, the MMRDA levied a penalty of Rs.5 crore on RAJV for the incident, including because no representative of the firm was present on site at the time. Reliance Infrastructure did not respond to Hindustan Times' email seeking comments on the probe findings....