Over time, things crack. Some cracks are expected, an unavoidable consequence of age. Others are from unexpected events, the right amount of pressure applied at the wrong time. But the most disappointing cracks are the ones that were preventable. The Transbay Transit Center in San Francisco was the unfortunate recipient of all three.
The first important crack was the reason why the terminal was created in the first place. In 1999 the Loma Prieta Earthquake damaged the existing Transbay Terminal, built way back in 1939. Despite being dated, the Transbay Terminal was situated a mile away from the Caltrain rail line that connected the city to its neighbors to the south. The plan was for the terminal to have buses on the top level, California’s new high speed rail connection on the ground level, and a tunnel connecting the Caltrain line to an underground terminal.
The construction of the terminal was done while its neighboring building, The Salesforce Tower, was being built. The massive project spanned four city blocks and over a million square feet. Designed by architects Pelli Clarke Pelli, engineered by Thornton Tomasetti the structure was to be covered by a wooded park and wrapped with a white aluminum facade patterned by physicist Sir Roger Penrose. It also carried the price tag of $2.2 billion.
In 2018 construction had finished and the transit center opened to the public. But then the next crack happened. Maintenance workers noticed a crack in the 4 inch thick, 2.5 inch wide, and 60 foot long steel beams that suspended the rooftop park above the bus terminal. The next day another crack was discovered and, concerned for the safety of everyone in and around the building, the center was closed. Luckily the old transit center had not yet been demolished, it was used as a staging area for the construction, so it quickly got put back into operation.
Investigations and lawsuits inevitably ensued to try to find the cause and responsible party of the failure. The top metallurgy specialists around the world were summoned to look at every possible cause of the cracks. In the end it was determined that the cracks were formed because of an oversight in construction. So important are the welds for these large metal beams that they need to be inspected after they are completed. In order to inspect them small 2 by 4 inch inspection holes are cut into the metal. These holes are cut with a acetylene torch which can leave a residue of a mineral called martensite. Martensite can produce microcracks, which can grow into full blown cracks, if not removed. For this reason building code calls for these inspection holes to be polished, which did not happen causing the problem.
The center reopened on July 1st, 2019 and is in use today, but the purpose of the project has yet to be fulfilled. Plans, like buildings, can crack too. Bringing the Caltrains through the tunnel and into the underground station would require them to be upgraded from diesel to electric power. These upgrades were scheduled but have now been put on hold until “early 2030s, pending funding.” California’s high-speed rail project has also run into delays. Currently the state expects to have the lines running by “the end of the decade.” The terminal also does not connect with the area’s popular subway system BART and has no plans to do so.
So, currently the $2.2 billion dollar “transit center” is nothing more than a bus stop. When it does connect many of the city’s expanding rail options it will be a useful piece of infrastructure. It has even helped catalyze the growth of the city’s financial district, thirteen new skyscrapers have been built or have plans to be built directly adjacent to the center. But until the authorities in charge of Caltrans and the high speed rail network are able to connect the center, its legacy will bear the cracks of negligence and poor planning.