In 1936—a century after their forefathers battled to secure Texas' independence—proud Lone Star residents gathered at the site to break ground for the San Jacinto Monument. The 44th Congress had pledged the sizable sum of $250,000 for a 570-foot memorial tower in San Jacinto State Historical Park, alongside the Houston Ship Channel.
Last year, the legacy limestone structure—towering 570 feet tall and crowned by a star stretching 60 feet wide—emerged beautifully from a complex, four-year restoration. The historic significance and complexity of the effort led to its winning an Award of Merit from Texas Construction as one of the state's best projects in 2000. Crews from two of Western's branch offices—Houston and Dallas—are pleased to have played a starring role in the success.
ALLISON VS. ANCHORS
The catalyst for the monument's restoration had occurred in the summer of 1989 during Hurricane Allison. A 30-pound chunk of limestone had tumbled from the side of the structure, crashing through a skylight into the museum below. Subsequent investigation revealed moisture from the Gulf had caused the cold-processed steel anchors securing the limestone to rust over time, leading to delamination and splitting of the stone.
In the view of Texas Parks and Wildlife Department officials, the restoration project was as complicated as the original construction, given the structure's ingenious design. The octagonal obelisk contains thousands of soft, porous limestone blocks alternating in size by one inch to offset the load, thus transferring the gravity load to the steel-reinforced concrete.
That single-inch difference on the monument's surface would suggest a similar symmetry inside. Not so, says Floyd Parks, divisional superintendent of Western.
In the original scope of work,”
we based our repairs on stones of 3.5″-4.5″ in depth. When we got into the project, everything changed.”
More than 500 stones in various areas of the base shift ranged from 5.5″-9″ in depth, with some as deep as 16″.
“In most projects, the solution would have been to build out the concrete behind the stone,”
Park adds. Not here.
“Because this is a historic monument,”
“maintaining the authenticity is very important.”
The revised restoration plan called for every stone of the San Jacinto Monument to be re-anchored with a stainless steel rod. Approximately 60,000 rods were installed in the course of the project, each requiring that a hole is drilled at a 30-degree angle into the stone and concrete substrate. The hole was then injected with latex-modified grout before a new anchor was inserted.
Worked from specially designed swing stages, crews also replaced more than 4,000 stones. The new limestone pieces were backed with masonry mortar and wedged in place until set. The wedges were then removed and the joints pointed. More than 3,500 Dutchman pieces were installed, along with 4,500 circular, three-inch limestone plugs. These plugs covered the core holes left after the removal of the old anchors.
With work completed on the shaft of the monument, attention shifted to the San Jacinto star—a 34-foot-tall, 220-ton structure of limestone with cementitious coating. Here, three challenges arose: scaffolding, given the structure's odd shape; unusual working planes, with virtually none square to horizontal or vertical; and lightning rod repair.
The scaffolding solution involved a custom design using a tube-and-clamp system and outriggers. Extensive engineering allowed crews to complete work on the various points and corners. The restored lightning dissipation system includes rods at the apex and four other points, all anchored through the structured steel. These are grounded in dissipation mats around the monument at ground level.
Despite the complexity f the project, the monument's museum remained open throughout the process.
Western congratulates the Texas Parks and Wildlife Department, project engineer Wiss, Janney & Elstner Associates, Inc. and its own Dallas and Houston branches on the completion of this award-winning restoration.