We’ve recently shared stories about the three bridges that preceded the Ann Richards Congress Avenue Bridge at the same Central Austin crossing over the Colorado River — a pontoon bridge from the 1860s, a wooden bridge from 1876 and a trestle bridge from 1884.

Those reports sparked interest at the local offices of HNTB, a national design and construction firm. Its Austin outpost is celebrating its 25th anniversary, but the company has been active in Austin construction for more than 100 years. In fact, Ernest Howard — the H in HNTB — helped design the surviving 1910 Congress Avenue Bridge that was widened and updated in 1980.

Like any good design company, it keeps meticulous photographic records of its work. HNTB preserved some images of the bridge’s construction and completion phases that we’ve never seen before. They sent us 11 photos, and every one is a sort of revelation.

MORE ON THE CONGRESS AVENUE BRIDGE:

• See the view from the Congress Avenue Bridge in the 1800s vs. now

• Austin’s first long bridge used ancient pontoon technology

But first a few words about Howard, a native of Canada and a graduate of the University of Texas, class of 1900, and the company he steered for decades. Howard was born in 1880, and he died in 1953. His parents were English, and he was born in Toronto. Because of his mother’s health problems, however, they moved to Jacksboro, northwest of Fort Worth, in 1893, “out in cattle country, 40 miles from a railroad.”

Howard earned degrees in science and civil engineering. He loved academic life and taught at UT, but his superior Dean Thomas U. Taylor accepted a position for him at Waddell & Hedrick in Kansas City, Mo., a company that traced its roots back to 1887. There, Howard learned bridge design from J.A.L. Waddell and, later, John Lytle Harrington. Howard started out in 1901 with a salary of $30 a month and later led the firm through the Great Depression.

According to the company’s records, the spread of the automobile changed the firm’s direction toward the infrastructure that supported the car craze. What is now known as the Ann Richards Congress Avenue Bridge, its graceful arches made of sturdy cast concrete, was known during planning stages as the “Colorado Bridge.”

The most arresting of the images unearthed by HNTB shows not one but three parallel bridges side by side, surely photographed from the bluff north shore of the river. The one on the left is the 1884 trestle bridge that survived the big 1900 flood and was later reassembled over Onion Creek in what is now Richard Moya Park south of Austin-Bergstrom International Airport.

The structure under construction in the middle is the current bridge, and to the right is a wooden bridge that appears to have been used temporarily during the big construction process. Workers can be seen in the foreground, while the pocked flood plains of the Colorado are to the right. I’m going to guess that the large buildings in the distant haze were part of the Texas School for the Deaf (too close and not in the right direction to be St. Edward’s University).

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A second photo shows a view to the north with the Capitol and a moonlight tower in the background. You can see that the trestle bridge is still there, and the 1910 bridge looks completed. What steals focus is the industrial detritus on the south shore. For those who think that downtown’s lake was always mantled with greenery and well-manicured trails, that has been the case for only the past 50 or so years. After all, why build anything beautiful along the river back before Highland Lake dams were raised upstream? Before that, catastrophic floods were routine, including three in the 1930s.

A good number of the other photos show more of the construction process, in particular progress on the pedestals and arches, as well as additional views of the shoreline and the temporary bridge.

Other images might be categorized as “glam shots” of the completed bridge, including one from the northwest that shows the Colorado River looking fairly clear and with pedestrians peering over the bridge’s railing. Another was taken from the middle of the bridge looking north toward downtown’s low skyline, including the Littlefield and Scarbrough buildings, our first “towers,” completed from their original designs in the first decade of the last century. Evidence of the trolley line can be seen below and above. It’s hard to get a bead on the sole vehicle in the middle distance, but it appears to be a heavily loaded wagon or truck.

These images are priceless, and I hope good copies go to the Austin History Center.

HNTB, which has offices in the Omni Austin Hotel building at 701 Brazos St., was not done with bridges. Among others it shaped have been the interchanges at MoPac at U.S. 183, Ben White Boulevard at Interstate 35, and Texas 45 at U.S. 183.

One last note on that 1910 Congress Avenue Bridge:

“Interestingly, when the bridge was expanded to add a lane in each direction in the 1980s, the foundation and columns of the structure did not have to be updated because it was so well designed,” says Michelle Dippel, vice president and Central and South Texas office leader for HNTB. “As a fellow Longhorn, it’s inspiring to me to see the impact our firm’s founder, Ernest Howard, has had on Austin. The Congress Avenue Bridge has become an important part of HNTB’s legacy in Austin and beyond.”

(Update: The address for HNTB's current Austin offices has been corrected. The spelling of Michelle Dippel's last name also has been corrected.)