Bridges: Ke-Ya Bridge

Case study: SOFO, ADAM System

Early age monitoring
Prestressing monitoring

Project Description

Summary: Box Girder Bridge Monitoring. Prestress stage monitoring.

Clients: Hsin Chu Municipal Government

Place: Hsin-Chu (Taiwan)

Period: 2004 - N/A

Installation: RouteAero Tech. & Eng. Consultants

Structure's short description: Ke-Ya brook bridge is located on Hsin Chu city crossed Ke-Ya brook. This bridge consists of several box girders with ten sets of prestress tendons for each span. Each girder is about 40 meters long and 12.5 meters wide. The Concrete pouring work is divided into two stages. The bottom slab of girder is first poured after rebar cages and formwork is set, and then the roof slab. The wood formwork inside the girder was removed 2 days after the roof slab was constructed. The post-prestress was proceeded the day after removal of formwork.

Aim of monitoring: The main purpose of this project is to monitor part structure during the early age, and prestressing. In this project, 3 SOFO standard sensors with thermocouples were embedded before pouring. The configuration of sensors was selected for monitoring deformation due to thermal effects induced by early age concrete hydration heat and the ambient environment influence after concrete was matured. Prestress stage was carefully monitored and recorded.

Number of sensor: 3

Main Results: Measurements of SOFO sensors and thermocouples were recorded from the beginning of concrete pouring works. Prestress load transfer was clearly identified by SOFO sensor. After formwork removal the girder deformation of at sensor location tends to be stable. During this period, creep effect caused by tendon force dominated the apparently deformation.

SOFO sensor and thermocouple at bottom slab

SOFO reading evolution during prestressing

Trend of deformation over two months after the pouring

Bibliography:

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