BR 1–159 — Bridge Replacement project on James Street Over Christina River

Christina River Bridge is located in Wilmington, Delaware. This existing bridge BR 1–159 is structurally deficient as its movable portion is inoperable due to heavy corrosion and section loss in its steel superstructure. The BR 1–159 Bridge Replacement project on James Street Over Christina River is a vital project for the Town of Newport.

Overview of the BR 1–159 Bridge Replacement Project

This bridge replacement project entails a new bridge structure which is to be constructed just east of the existing bridge alignment. The new bridge being constructed is 393’-11 7/8” long having 5 spans. Rite Geosystems, our subsidiary in the USA, was entrusted with providing the entire instrumentation for the project. This included supply and installation of geotechnical instruments.

Need for Monitoring BR 1–159 Bridge Replacement Project

When talking about the need and importance of monitoring, it is imperative to talk about the safety risks involved during construction works. The existing seventy-two inch Christina River Force Main (CRFM) concrete sewer pipe was located quite near the construction works. It serves the entire New Castle County, and had little to no system redundancy. Thus, the monitoring of CRFM utility was critical during construction works. It was also necessary to protect the sewer pipe against adverse impacts associated with equipment loads, ground settlement and vibrations as a result of the construction activities.

The instrumentation monitoring plan included the installation of various geotechnical instruments to monitor sub-surface soil conditions around the CRFM prestressed concrete cylinder pipe (PCCP). Rite Geosystem Inc., USA was given the responsibility of carrying out these monitoring works.

Monitoring Solutions Offered for the BR 1–159 Bridge Replacement Project

The monitoring plan mainly included sub-surface ground movement and ground water pressures in the soil around the CFRM utility. Monitoring solution provided by Rite Geosystem included in-place inclinometers and piezometers.

Instruments Used

– Piezometers

Piezometer plays an important role in maintain sub-surface water pressures. This prevent from underground water exerting pressure on the underground utility or surface structures.

– In-place Inclinometers

In-place Inclinometer is used to monitor the lateral soil movements. It helps in determining whether the movement is within the design’s tolerance …[Continue reading]