Lamar Boulevard Bridge

In the late 1930s, Austin had greatly outgrown its original town plan on the north bank of the Colorado River. In 1939, the city planned a new major north–south thoroughfare to run to the west of the Texas State Capitol and connect the city's western housing developments. This new street, eventually named Lamar Boulevard, would roughly parallel the course of Shoal Creek, reaching the river's edge near the creek's mouth. On the south bank, the boulevard would continue onward to join what was then Texas State Highway 20, leading to Fredericksburg, Texas. As the city began building the boulevard, the Texas Highway Department (now the Texas Department of Transportation) was charged with designing and building a bridge to carry Highway 20 across the river. On July 7, 1994, the bridge was added to the National Register of Historic Places in recognition of its architectural significance and its continuing importance to Austin's transportation infrastructure. Addition of parallel pedestrian bridge The bridge was built with no dedicated bicycle lanes and with narrow sidewalks separated from the street only by low curbs. In the 1990s, the site became notorious for road accidents involving cyclists and pedestrians. The City of Austin explored possibilities for widening the bridge to add space for non-automotive traffic, but the Texas Historical Commission opposed these proposals out of a desire to preserve the bridge's historic design. This conflict eventually led in 2001 to the construction of the James D. Pfluger Pedestrian and Bicycle Bridge, situated to the east of the Lamar bridge. ==Design==

The Lamar Boulevard Bridge is an open-spandrel deck arch bridge made of poured-in-place reinforced concrete. It crosses the Colorado River with six identical spans, supported by five concrete piers on the river bed and by concrete abutments at the ends. The deck carries four roadway lanes, flanked by a sidewalk and metal balustrade on either side. The piers (originally visible, but now largely submerged) and pedestrian guardrails show Art Deco details, such as vertical fluting, which indicate the period of the bridge's construction. The piers stand on spread-footing foundations resting on limestone bedrock. Each span rests on two parallel concrete segmental-arch ribs, each wide and thick, rising to a clearance of above the springline. A series of slender vertical columns rises through the open spandrels to support smaller longitudinal arches and transverse floor beams immediately beneath the deck. The floor beams cantilever roughly beyond the piers and columns to support the sidewalks and balustrades. The pedestrian guardrails on the approaches to the bridge are solid concrete panels, while those along the deck take the form of tubular steel railings, linked by vertical steel bars and supported by concrete columns. Eight of these columns rise from each deck span, punctuated by taller, heavier columns above the piers, which are built to support street lights. ==See also==