In case you haven’t seen the signs that have been up along the routes leading to the 1st Avenue South Bridge – WSDOT has just sent a reminder: It will be completely closed 7 am-3 pm this Saturday in the NORTHBOUND DIRECTION ONLY for maintenance work. According to WSDOT’s advisory, a cracked half-century-old steel plate will be replaced during the 8-hour shutdown. (We’ll let you know here on Saturday if it reopens early – this alert also is atop the WSB Traffic page, which we continue tweaking to include more day-to-day information that you might miss in the main news stream here.)