Once considered a solid structure, conditions along the northside of the Greene Street bridge in Carlsbad deteriorated to the point of needing a months-long repair job starting Oct. 1, according to the New Mexico Department of Transportation.
Jonathan Boyle, bridge supervisor for the New Mexico Department of Transportation (NMDOT) District 2 office in Roswell, said concerns of the substructure on the Greene Street Bridge prompted closure more than a month ago.
He said concrete along the bridge started failing due to a problematic pier cap.
Pier cap beams are the most common prefabricated element of substructure in a bridge, per a USDOT website.
Before the problem was discovered, the bridge was rated good based on data from the U.S. Department of Transportation (USDOT) Federal Highway Administration National Bridge Inventory (NBI).
When rating bridges, NBI looks at substructure, superstructure, and overall rating. A rating of seven to eight is considered good for bridges, per the NBI.
Boyle said the bridge’s rating fell from a good rating to a low rating of three when the trouble started.
“I’m sure the traveling public felt a bump when they went down the westbound lane. That bump was the beam starting to slip underneath the bridge,” he said.
“It was the pier cap starting to fail. That is considered a bad structural failure,” Boyle added.
He said other pier caps started breaking up, placing motorists in imminent danger during the summer months.
Greene Street also known as U.S. Highway 62/180 is a major east-west passage for passenger and commercial traffic heading into Carlsbad from larger areas like Hobbs or West Texas.
It’s popular route for oilfield workers in Eddy and Lea counties, and the main road for people commuting to the Waste Isolation Pilot Plant (WIPP) nuclear repository near Carlsbad.
NMDOT estimated 16,000 vehicles travel along the bridge per lane every day day
NMDOT closed the westbound lanes of the bridge Aug. 8 and diverted traffic to New Mexico 200 via the George Shoup Relief Route to northern Carlsbad. The eastbound lanes remained opened for traffic out of Carlsbad.
NMDOT, the City of Carlsbad and Burlington Northern Santa Fe (BNSF) LLC agreed to a median removal on the southern portion of the bridge to allow one lane each of east and westbound traffic, after the northern portion of the bridge shutdown and closed the western lanes, the City of Carlsbad noted in a news release.
“When things started failing on this bridge. It started going quickly. That’s why it was escalated to one lane closed to all of a sudden, the bridge being close completely to all traffic,” Boyle said.
He said NMDOT was authorized to shutdown roads maintained by the State of New Mexico and detours onto City of Carlsbad or Eddy County roads couldn’t happen without permission from either entity.
“That’s why the first week it was a little bit chaotic its because we could only use our own roads to detour,” Boyle said.
NMDOT District 2 Spokesperson Candace Barela said work on the bridge’s northside would start Oct. 1 and last nearly six months. NMDOT estimated cost of the project was $1 million.
Boyle said the money is in place and a contractor is prepared to repair the concrete, replace bearings and pier caps, and repair the joints that hold up the bridge.
“On other parts of the bridge we’re going to inject a high strength glue. It should stop cracking on the other parts of the bridge,” he said.
Carlsbad Mayor Dale Janway said work on the bridge was needed as blockage and limited traffic options were an ordeal for residents and businesses who reported a loss of revenue due to traffic congestion.
John Waters, executive director of the Carlsbad Department of Development, a business recruiter for Carlsbad and Eddy County said work on roads like U.S. 62/180 were critical for business and community development.
“We are happy that the work is being done and encourage the state to make this a top priority,” he said.