Highway officials are trying a number of methods to fasten the loose metal plate on the Río Virilla bridge.
Monday workmen applied a path of asphalt, but that began to break up under the weight of traffic.
Now officials are closing the eastbound lane in order to solder the metal. There even are plans to glue it with epoxy.
The expansion joint on the Autopista General Cañas bridge has been a problem for six years. There have been problems with the loose metal on both the eastbound and westbound lanes.
Officials have said that the bridge is too flexible and that this causes the metal to come loose. There are plans to remodel and widen the bridge.