A visitor to the Silver Lake branch library on Thursday was surprised to find the Glendale Boulevard building closed. A sign posted on the glass entry door said the building would remain closed because of a building safety issue, according to a woman who stopped by the library. What happened? Michael Saint-Onge with the Friends of the Silver Lake Library said a large glass panel over the entrance had been smashed and boarded up. The concern about falling glass and the need to make repairs prompted the closure. The library is scheduled to open today, said a library department spokeswoman.