PHILADELPHIA (AP).- It’s not typical for a loading dock to be the celebrated subject of a groundbreaking ceremony, but Frank Gehry is not your typical architect. Gehry joined more than 100 dignitaries, philanthropists and art aficionados Tuesday at the The Philadelphia Museum of Art to mark the start of construction on his 68,000-square-foot, $81 million underground utility space. Museum officials said the new space will provide much needed improvements for the care and storage of art works and will make deliveries simpler — from food to fine art. More important to visitors, it will return a vaulted walkway that runs through the length of the museum — and has been used for shipping and receiving since the 1970s — to its original purpose as a street-level visitor entrance. The “loading dock” is expected to be completed in 2012. After that, planning will begin on a vast underground gallery, also designed by G