It may be open but the bridge is still broken...

Design flaws, fabrication errors and snapped bolts dogged the construction of the still-incomplete bike path on the new Bay Bridge eastern span, leading to at least $3.8 million in cost overruns on its handrail system alone, Caltrans documents show.

The 2-mile-long, rail-lined path opened along with the new eastern span earlier this month and already has proved popular with bicyclists, walkers and runners, even though it stops short of its eventual terminus on Yerba Buena Island. The path will not be linked to the island until 2016, after the old eastern span is demolished.

Problems with the railings on either side of the path - particularly 29 gates interspersed along the route to allow emergency access from the roadway - were evident shortly after the fencing was installed in 2007 and early 2008, the Caltrans documents show. The agency says the problems have been fixed, with money that came from a contingency fund financed by toll payers, and that the path is safe to use.

"We took all necessary steps to ensure the safety and quality of the bike path," Caltrans spokesman Will Shuck said Wednesday. "It will be a treasure for generations."

Caltrans has already had to re-engineer a pair of seismic stability structures on the bridge because contractors installed at least 32 faulty metal rods, and the integrity of hundreds of other vital rods and bolts has been called into question.

"It's symptomatic of a systemic problem," said Bob Bea, a professor emeritus with UC Berkeley and an expert on failure analysis of major structures. "The bridge and the bike path, they are complex elements - I think it's becoming clear that the required level of scrutiny and checking has been deficient."

Many of the problems with the bike path railing were signaled more than five years ago by a Caltrans inspector named Greg Roth, who documented them in a construction log to his supervisors.

Roth said the bike path's contractor, Kiewit/FCI/Manson, and a subcontractor, Kwan Wo Ironworks Inc. of Hayward, "have displayed a total disregard to contractor compliance." The firms did not intend to fix the problems, so Caltrans was going to look to other contractors to design and install replacements, Roth indicated.

Roth still works for Caltrans, said Shuck, who declined to make him available for comment. The spokesman said Balan was also unavailable for comment. Caltrans ended up paying the eastern span's main contractor, American Bridge/Fluor, more than $3 million to make the fixes in 2011. But that was not the end of the problems.

In the process of making the repairs, crews discovered that tapered pieces of metal inserted where the rail posts were bolted down on the path were too thin. The metal pieces, known as shims, were supposed to keep the rail upright. They tended to slide out of place, creating a safety hazard, according to Caltrans documents.

While replacing the shims, crews also found that many of the bolts holding down the rail had been incorrectly welded and had sheared off. The bolts were supposed to be able to move as steel segments of the bike path expanded and contracted, depending on the air temperature, but had been welded too tightly. About 200 ultimately were replaced.

Those problems cost a combined $780,000, the Caltrans documents show. The fixes were completed this year.