A four-year legal spat over the Hoover Dam bypass project’s collapsed cableways has ended in a private settlement stemming from an April 20 arbitration ruling. A joint venture of Obayashi Corp., San Francisco, with PSM Construction USA Inc., Brisbane, Calif., will reimburse American Bridge Co., Coraopolis, Pa., an undisclosed amount for a cableway system that broke in 2006, causing a two-year delay.

In 2005, the joint venture signed a two-year, $105,000-a-month lease with American Bridge Co. to use two pairs of refurbished, 330-ft-tall lattice-framed towers with 2,500 ft of 3-in-dia. cableway strung between them. The so-called high lines function like a clothesline: About 890 ft above the Colorado River and a quarter-mile from the Hoover Dam, the cable was stretched across Black Canyon and would have enabled 104 precast bridge segments to be slid into place.

On Sept. 15, 2006, a tower on the Nevada side of the canyon toppled over during 50-mph winds, halting construction. Obayashi/PSM blamed “tubular corrosion, welding defects and other weakened conditions” and sought $74 million from American Bridge Co. in damages and delays. Meanwhile, American Bridge Co. claimed the joint venture’s improper rigging led to the collapse and sought $6 million for destroyed equipment.

A three-person panel arbitrated the case earlier this year over 28 days in Las Vegas and determined that “neither side established with certainty … the actual cause of collapse.” Still, it said American Bridge Co. was entitled to reimbursement—with interest—for lost lease revenue and equipment damage. The final settlement amount remains confidential.

Prior to the arbitration panel’s ruling, Obayashi/PSM negotiated with the Federal Highway Administration to waive potential $8,000-per-day fines for completion delays. FHWA never ruled the incident a force majeure. FHWA spokesman Doug Hecox declined to discuss details but noted the $240-million project is not over budget. The 1,900-ft-long, 277-ft-deep twin-rib arched bridge will open in November.