Precast wall parapets with excellent workability and maintainability

EMC Precast Wall Parapet™

Summary

To minimize on-site work, special bolts are used to secure the wall parapets to the deck slabs and to connect the precast members to each other. These bolts are covered with a protective tube so that they can be easily removed when the wall parapets are replaced. Even when replacing a wall parapet that has been damaged by an accident, the replacement work on site can be completed in a few hours, thus reducing the number of days of traffic control.

This technology was jointly developed by Metropolitan Expressway, Obayashi Corporation, and the PGF Association.

Features

High Production Rates

  • Compared to conventional cast-in-place wall parapets, the use of precast members, fixing to deck slabs, and connecting members with replaceable bolts enable a 20% reduction in construction time per km.

High Load-Bearing Capacity

  • Vehicle collision tests have been conducted on precast wall parapets and confirmed that specified performance requirements (in Japan) were met. Static loading tests have also confirmed that the walls can withstand more than four times the design load (Class SB(*1) for a straight wall). By adjusting the bolt and plate dimensions, severe damage to the deck slab can be avoided in the event of a vehicle collision.

Durability

  • Each component of the EMC Wall Parapets is manufactured at a factory which enhances quality control. Durability is ensured by applying a heavy-duty anti-corrosion treatment (composite coating of zinc and epoxy) to the bolts used, inserting the bolts into protective tubes to prevent rainwater from seeping into the bolts, and taking multiple waterproofing measures such as filling around the protective tubes with non-shrink mortar.
Vehicle crash test
Static Loading Test (Load-Displacement)
  • *1　Class SB is a standard performance class for highway wall parapets in Japan.

Projects

  • Metropolitan Expressway, Highway No.1 Haneda Line Retrofit (Higashi-Shinagawa Pier, Samezu Landfill Area)

  • Construction

  • Completed

  • Chuo Expressway Matsugahira Bridge: Deck Slab Replacement

  • Construction

  • Completed

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