NWP Company Barge Incidents

  • Blog

20 Dec 2018

In April 2018, two barge accidents impacted the Black Point, California Bridge causing damage to the steel truss and the timber fender protecting it. ARE-AirShark analyzed the Brazos Junction Bridge Truss (Swing Spans) Bridge in order to help return the bridge to its previous state as well as assess the condition of unaffected bridge members. These two closely timed incidents proved very detrimental to the lifespan of the bridge which crosses over the Petaluma River.

The bridge itself spans a total 294 feet at a 10 mph speed limit. The recommendations and analysis supplied by ARE-AirShark were executed by Koppers Contracting Company. It was imperative that the timber fender protecting the bridge be repaired in a timely matter due to the high concentration of barges in the area.

On March 26th, a Dutra barge struck the right truss at L2 and possibly the right truss at U1 of the Black Point Bridge. ARE-AirShark’s Project Engineer determined that the deck & approach portion was unfazed by the impact of the barge. However, repair was recommended in the superstructure and substructure approaches. In the superstructure, Diagonal U1 L2 was recommended diagonal repair in addition to the replacement of damaged channel members and lattice. Furthermore, all rivets at L2 gusset plate were recommended to be replaced with high strength bolts. In the substructure, on the fender, the replacement of broken longitudinal timbers was called for. Also, the center pivot bearing required inspection for damage of the center pin and the realignment/re-position of the bridge’s wheels was recommended to avoid scraping of the track.

On April 16th, a Westar barge struck the Black Point Bridge Swim Span Fendering. The impact created a dire need for the repair of the fendering system. This is due to the fact that the bridge became unprotected from the mariner traffic, leaving the swing span steel truss at risk for large quantities of damage. ARE-AirShark assessed the bridge after the impact and suggested a multitude of repairs and replacements to bring the bridge back to it’s original state.

For this specific incident the substructure required recommendations. ARE-AirShark suggested that the damaged piles and fender framing be replaced. This included 26 piles which could either be completely replaced or re-used and re-driven to its required location. Recommendations were also made that fenders along the west edge of the fender system could be be removed and assessed and reused if undamaged.

The two Black Point Bridge incidents occurred so close to each other that inspection and repairs needed to occur immediately to ensure future damage be avoided. ARE-AirShark’s quick and cautious inspection led to the recommendations of the most cost-efficient replacements and repairs. The repairs and restoration followed through by Koppers Contracting Company have ultimately led the Black Point Truss Bridge back to its original state

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