{
  "type": "article",
  "title": "Mandi Viaduct at 9 Mile Redesigned on Double Pillars with ₹125 Crore Outlay After NHAI Headquarters Review",
  "summary": "NHAI headquarters has ordered a structural redesign for the proposed 350-metre viaduct at landslide-prone 9 Mile in Mandi, shifting from a single-pillar plan to a sturdier double-pillar system while a ₹35-crore retaining wall stabilizes current traffic.",
  "content": "A major structural revision has been mandated for the upcoming viaduct bridge at the landslide-prone 9 Mile stretch in Mandi district, part of the Kiratpur-Manali four-lane national highway project in Himachal Pradesh. The local project division of the National Highways Authority of India (NHAI) had initially drafted and submitted a single-pillar structural blueprint for the site. However, during comprehensive technical evaluations in Delhi, NHAI headquarters raised specific objections regarding the single-pillar layout and formally directed the field team to reconstruct the design around a sturdier double-pillar foundation.\n\nTackling Chronic Landslides and Preparing the Modified DPR\nThe hillside at 9 Mile has experienced severe instability for a prolonged period, causing persistent transit disruptions along this vital mountain corridor. Heavy downpours during the monsoon seasons of both 2023 and 2025 triggered substantial rockfalls and cascading debris across the carriageway, stranding commuters and cutting off essential movement. To eliminate this chronic geological hazard, engineering teams finalized the concept of constructing an elevated 350-metre viaduct bridge spanning across the unstable terrain.\n\nProject Director Varun Chari stated that the preliminary single-pillar design carried an estimated budget of ₹125 crore. Following directives from central authorities to revise the scheme, the DPR technical wing in Mandi initiated work on drafting a fresh engineering layout supported across two parallel rows of pillars. Once this revised blueprint receives internal technical clearance, the amended proposal will be dispatched back to Delhi for formal administrative and financial sanctions.\n\nEngineering Function of Mountain Viaducts\nIn highway engineering, a viaduct bridge operates as an elevated road deck raised high above ground level on a succession of structural pillars rather than resting directly on surface terrain. In rugged mountainous areas, this technique is strategically deployed where highways must traverse severe slope depressions, geological faults, or active slide zones. By lifting traffic overhead on elevated columns, the vehicular corridor stays entirely independent of unstable slope movements and rolling rock masses below.\n\n₹35-Crore Retaining Wall to Secure Existing Traffic\nTo ensure vehicular traffic continues flowing safely along the present alignment throughout the viaduct's construction period, NHAI is simultaneously executing protective civil works on site. A comprehensive retaining structure, extending from the bottom slopes upwards, is being erected to anchor the existing road. This interim stabilization contract, valued at roughly ₹35 crore, has already been awarded to a specialized firm, and active construction is underway on location.\n\nInfrastructure development along the Kiratpur-Manali four-lane also includes another key component at Thalout, where Himachal Pradesh's first 500-metre box tunnel is slated for development with an allocated budget of ₹200 crore to provide significant long-term ease for tourists.\n\nWhat this means for you\nUpgrading the 9 Mile viaduct to a double-pillar layout and building a ₹35-crore retaining wall will safeguard commuters from chronic landslide blockages along the Kiratpur-Manali highway corridor.\n\n• In Himachal Pradesh: Construction of the ₹35-crore retaining wall will shield the existing route against falling stones, preventing prolonged transit paralysis during monsoons. Once the 350-metre viaduct is ready, agricultural transporters moving apple produce and local freight will face far fewer road delays.\n• Across India: Vacationers and long-distance motorists heading toward Kullu-Manali will enjoy far safer driving conditions with reduced weather-induced disruption. The combination of this elevated viaduct and the ₹200-crore Thalout box tunnel significantly upgrades northern highway connectivity.\n• For Road Safety: Shifting to a twin-pillar foundation increases structural resilience against slope instability, ensuring heavy commercial vehicles can pass safely. Elevated bypasses minimize direct contact with unstable soil beds prone to slippage.\n• For Regional Economy: Year-round, reliable highway infrastructure protects tourism businesses in Mandi and upper Himachal from costly seasonal closures. Stable transport corridors also preserve smooth supply chains for regional markets.\n\nWhy this happened\nNHAI headquarters rejected the single-pillar proposal for the 9 Mile viaduct due to acute slope instability and ordered a double-pillar design to ensure long-term structural integrity.\n\n• History of Severe Landslides: Torrential rains during the 2023 and 2025 monsoon seasons sent immense debris and boulders crashing down the 9 Mile hillside, severely crippling connectivity. These recurring geological failures necessitated building an elevated 350-metre viaduct over the hazard zone rather than paving a standard surface roadway.\n• Engineering Assessment at Central Level: Technical evaluation of the ₹125-crore single-pillar proposal in Delhi determined that a dual-column arrangement offers superior balance against seismic and hillside pressures. The field DPR team was consequently instructed to scrap the single-pole schematic and redraft the layout on double pillars.\n• Need for Interim Traffic Protection: Heavy traffic on the Kiratpur-Manali alignment cannot be halted while the viaduct is built over several years. NHAI therefore sanctioned a dedicated ₹35-crore retaining wall extending up the slope to prevent active rolling stones from striking present commuters.\n\nQuestions & Answers\n\n1. Why is the viaduct bridge design being modified at 9 Mile in Mandi?\nNHAI headquarters raised technical concerns over the single-pillar plan and directed the team to build it on a sturdier double-pillar system.\n\n2. What is the estimated cost of the proposed 350-metre viaduct bridge?\nThe construction of the 350-metre viaduct bridge carries an estimated project cost of ₹125 crore.\n\n3. How is existing traffic being protected while the bridge is under construction?\nA protective retaining wall stretching from the lower base upward is being erected at a cost of around ₹35 crore to secure current vehicles.\n\n4. What prompted the decision to construct an elevated viaduct at 9 Mile?\nThe area suffers from recurrent landslides, having experienced heavy debris and rockfalls during the monsoon seasons of 2023 and 2025.\n\n5. What are the details of the proposed box tunnel at Thalout?\nHimachal Pradesh's first 500-metre box tunnel is planned at Thalout along the four-lane highway with an outlay of ₹200 crore.",
  "url": "https://trendkia.com/en/himachal-pradesh/mandi-ke-nau-mila-para-125-karora-rupaye-ka-vayadakta-pula-aba-dohare-pilara-para-taiyara-hoga-nhai-mukhyalaya-ne-dijaina-badala-43257",
  "category": "Himachal Pradesh",
  "publishedAt": "2026-10-05",
  "tags": [
    "Mandi Four Lane",
    "Kiratpur Manali Highway",
    "NHAI",
    "Viaduct Bridge",
    "9 Mile Mandi",
    "Himachal Pradesh Roads"
  ],
  "language": "en",
  "site": "TrendKia"
}