The installation of a long-promised pedestrian bridge across West Street just south of the World Trade Center site has been delayed yet again after the discovery of a weld defect that would compromise the structure’s 75-year lifespan.

The West Thames Street Bridge was originally poised to be installed in 2010 but, according to Crain’s, a series of gaffes has seen the installation pushed back time and time again and has led to the ballooning of the budget to more than $40 million. The bridge is being funded in part by the Lower Manhattan Development Corp. and is being overseen by the state’s Economic Development Corporation.

After nearly a decade of delays, the bridge was poised to be installed this fall. But with the discovery of the weld defect, that has become unlikely. “Certainly we’re … not meeting the installation this fall, and I strongly doubt that we will have the bridge installed by the spring of next year,” David Emil, president of the LMDC, said at a July 26 meeting.

The 230-foot span was designed by WXY Architecture and engineering firm Thornton Tomasetti and is poised to replace a temporary pedestrian bridge positioned slightly north at Rector Street. An original design by SHoP Architects was scrapped.

“This is obviously an example of terrible planning and insufficient attention to the engineering,” Thomas Johnson, an LMDC board member, said at the meeting. “And it’s causing a big delay in something the neighborhood needs and wants. And we ought to be ashamed of ourselves because we approved it without satisfying ourselves on those matters.”