orkmen last week installed the first sections of steel for a ramp system that will become an architecturally prominent feature of Lerner Hall. It was made by Eiffel Constructions Metallique of Nanterre, France, descendant of the original Alexandre Gustave Eiffels engineering firm. The structure will take the form of three gently slanting ramps of three sections each, which will be raised and welded together during the next three weeks. They will be fully visible behind an uninterrupted clear glass exterior wall attached to the ramps by clusters of steel fingers. It will be the second Eiffel building in New York City, after the Statue of Liberty. The architect is Bernard Tschumi, dean of the Graduate School of Architecture, Planning and Preservation, in association with Gruzen Samton.