On October 13, Obayashi announced that it has developed
the “Krabbe Wagen Method,” a method for building the pier head segment,
the part of a prestressed concrete (PC) bridge that sits on top of the pier.
By making minor modifications to existing form travelers,
the method eliminates the need to assemble and dismantle
large brackets and scaffolding and shoring.
According to the company, it reduces construction time and labor
by about 30% compared with conventional methods.
The Challenge: Preparation for the Pier Head Takes Time
The method targets the balanced cantilever method,
in which bridge girders are extended to both sides from the pier head.
Conventionally, a pier head wide enough to hold two form travelers,
the dedicated equipment used in this method, is built first.
In a work breakdown presented by Obayashi,
assembling and dismantling the scaffolding and shoring for this step
account for 48% of pier head construction work.
Because this is also work at height,
improving efficiency and safety had been a challenge.
What Changes: Using Form Travelers to Widen the Pier Head in Three Stages
In the new method, a pier head of the same width as the pier is built first.
Next, one form traveler is installed to build one side,
and then a second is added to build the other side.
The main members of the form travelers are arranged
so that they do not interfere with each other.
After the pier head is completed, an added slide mechanism
returns the main members to their conventional positions,
allowing work to switch to the conventional construction method.
In a schedule comparison presented by the company,
the construction period for the pier head is 100 days with the new method,
compared with 140 days for the conventional method.
The company says the method also improves safety by reducing work at height.
The figure of about 30% refers to pier head construction
and is not a reduction rate for the bridge project as a whole.
LC Signal’s Perspective: An Improvement That Is Easy to Adopt Even After Winning a Contract
Obayashi explains that existing methods involving major structural changes
or modifications to form travelers could be difficult to apply
after a contract had been awarded.
This method makes use of existing equipment,
and work can return to the conventional method once the pier head is complete.
Along with the shorter schedule, ease of adoption on site
seems likely to be a factor in deciding whether to use it.
The company plans to apply the method to PC bridge projects going forward.
Key Sources
-
Obayashi official announcement (Japanese), October 13, 2026:
PC橋梁工事における柱頭部施工の効率化・安全性向上を実現する新工法「クラッベワーゲン工法™」を開発
This article was prepared with AI assistance using publicly available information
as of October 14, 2026.
Announcement dates follow the dates shown on the official pages.
Figures for construction periods, work shares, and labor savings are based on
the company’s explanation of pier head construction.
“LC Signal’s Perspective” reflects this publication’s interpretation
of the available information.