Restoring An Icon

The perky fourth graders who came to testify were a sharp contrast to the lawyers and lobbyists who normally frequent the legislative chambers, and seldom have those dour

Workers rebuild buttresses high on the tower of the state capitol. Loose limestone blocks discovered in these structures, 320 feet above the ground and 40 feet above the public observation decks, posed a safety hazard. The structure had to be completely rebuilt, resulting in considerable expense and delay.

professionals been as effective as these newcomers. "Save this for us, for our kids and grandkids," was the core of their message, and the Nebraska Legislature's Appropriations Committee bought their every word.

The youngsters testified on behalf of a beloved old-timer approaching a 70th birthday with stiff joints and cracking skin. They were concerned about their towering state capitol, a Nebraska icon since anyone in the chamber could remember.

This is the capitol that Nebraskans began building in 1922, proceeding in stages on a pay-as-you-go basis, and persevering to finish the fourth and final stage in 1932 despite the Great Depression. Richly appointed with tile ceiling and floor mosaics, murals of Venetian glass and oil-on canvas, vaulted ceilings and other finery, this tower on the plains has been a source of pride for generations of Nebraskans, and is widely recognized as an architectural masterpiece.

However, cracks and chips in the building's limestone skin, entire blocks displaced by unseen forces, and crumbs of mortar and limestone falling on people below, prompted an investigation in 1995. The findings sent the fourth graders and others to the legislature seeking action, and the senators responded with a $20.6 million appropriation for an eight-year restoration of the classic structure.

The study produced a long list of issues that needed attention - in the 370-foot tower, its dome, its three-story base, and the north entrance. Some problems were blamed on the ravages of time,

Heavy scaffolding encloses the capitol tower, the focus of most work in 2001.

such as the inevitable failure of pointing mortar in the joints of the limestone exterior, or on the failure or omission of sealants, mortar and flashing, which allowed water to penetrate the structure and raise havoc within its walls. Other problems were traced to the state of construction technology at the time the capitol was built, to errors, or to shoddy work. Yet others went undetected until restoration began, thus raising costs in a time of fiscal uncertainty and causing delays.

Outdoor work on the capitol's restoration began January 4, 1999, with Mike Rindone, Capitol Architect for the State Building Division, as project manager, and Mark 1 Restoration of Dalton, Illinois, as general contractor. The work laid out for that year involved renovation of the north entrance and its massive flanking walls, commonly called the "buffalo wing walls" because of the carved images of bison that decorate their facades.

Water entering the interior of the walls made their soft brick cores expand and press against the limestone veneer, displacing some blocks by an inch or more.

Workmen completely dismantled each wall and replaced its brick core with concrete. An air space between the core and the limestone exterior provided interior drainage. "Eventually, water will get back in there. There's no way around it. But now it has a way out, so it doesn't create havoc," Rindone said.

Water was also to blame for the deterioration of the concrete slab supporting the north stairs. To better understand the damage, the granite steps were removed, a hole was bored in the underlying concrete, and a small video camera was slipped into the void below. It showed a large space, as

Victor Malas of Lincoln cleans lead flashing in preparation for soldering during renovation of a tower expansion joint. The original soft clay brick of the wall's core is exposed at left, and the new water resistant brick is visible in the center of the photo.

wide as the stairs and filled with a jumble of fallen timbers, the remains of the framework that supported forms when the slab was poured 70 years ago. "It was like looking down into the Titanic," Rindone said.

Using a low-tech but effective technique, workers searched for deteriorated concrete by listening for hollow sounds as they dragged a heavy chain across the surface. They chiseled or ground away the bad concrete and replaced it, added waterproofing, then reinstalled the original granite steps. They also disassembled and refurbished stairs on the second floor leading to the promenade with waterproofing and proper flashing, which ended years of chronic water problems in offices below.

The biggest problem revealed by the 1995 study, however, was a fundamental misunderstanding during the tower's construction that robbed it of flexibility and changed its distribution of weight in a way contrary to the building's design. Rindone said the capitol's tower is a skyscraper, fundamentally different from a traditional load-bearing building. A skyscraper's steel framework supports both its floors and the building's exterior masonry skin.

Rindone explained the importance of flexibility in the capitol's tower as it moves ever so slightly. "Consider the daily thermal extremes that we have in Nebraska. Every day as the sun comes up, the east side of the building warms, causing that side of the building to expand, while on the west side, the stone remains cold and contracts. The tower bends, compressing stone on the

Lightning strikes melted quarter-sized marks in the Sower's head over the years. Mike Rindone points to a smaller mark made by a secondary arc from a strike.

west side and pulling stone apart on the east. As the sun arches across the sky, the side of the building facing the sun warms and expands while the opposite side cools and shrinks . . . every day, for 70 years, like a corkscrew," he said. The result has been fissures and cracks in the masonry walls, more so near the bottom of the tower "because that's where the stresses are being resolved," he said.

The tower's design employed a steel beam and shelf angle assembly at the perimeter of each floor to support the exterior masonry wall for that floor. The stone and brick masonry walls were built after the steel frame was in place. The masonry was installed tight to the underside of the beam and shelf angle.

"That is where the mistake was made. The building's designers felt flexibility was needed in the tower masonry. They designed a joint that pierced only the limestone veneer but, unfortunately, did not continue through the brick behind the stone. This resulted in a rigid wall from the base

Limestone blocks removed for work on expansion joints are stored on the heavy-duty scaffolding. The stones are numbered for easy reassembly.

of the tower to the 14th floor," Rindone said. "I think what you had was the new emerging technology of skyscraper construction running headlong against the older traditional methods of masonry construction."

The solution appeared simple, but its execution was a monumental effort, requiring the entire construction season of 2000. At each of six floors in the tower, workers removed three courses (horizontal layers) of limestone and large quantities of brick to expose the face and underside of the perimeter beam and shelf angle. The steel was cleaned, coated and flashed with lead flashing to protect the steel and wall from water intrusion in the future.

New water-resistant bricks were laid back into the wall, and a 5/8-inch "gap" was left between the bottom of the steel beam and shelf angle and the top of the new brick. The gap, called a soft joint, is filled with a neoprene pad that extends from the back of the wall to the front edge of the shelf angle. It provides flexibility for the tower and allows the masonry and steel to expand and contract. Each floor now supports only the weight of masonry surrounding that floor without supporting the weight of masonry on the floors above.

People in Lincoln who had not heard or read news reports about the capitol restoration certainly became aware of it during this phase. The tall, slender silhouette of the capitol assumed a bloated look, visible from all over the city, as scaffolding encased the tower.

The heavy-duty scaffolding was expensive but worth it, according to Rindone. "It kept people safe," he said. It also handled the weight of stone as the walls were disassembled, the largest single block weighing 3,500 pounds. Workers did not have to lower stone and store it on the ground while they modified a stress joint, then raise it back up when finished.

The schedule for 2001 was busy with eight projects underway, all of them on the tower. The restoration of the Sower, the 19-foot bronze figure and its 11-foot pedestal atop the capitol dome, generated more public interest than any other facet of the restoration so far.

The state was awarded a Save Outdoor Sculpture Grant to evaluate the physical condition of the Sower. The grant is funded through a partnership between Target Stores and the Smithsonian Institution. The Sower was found to be in excellent shape, according to Rindone.

Jensen Conservation of Omaha recommended patination of the entire statue to correct metal degradation on several areas of the sculpture. Patina occurs naturally on bronze when the surface

Michael Breen (foreground) and Juan Flores, both of Lincoln, replace pointing mortar of the capitol tower. Old mortar is visible at right.

of the metal oxidizes and turns green, but this takes time to develop. To accelerate the process, the conservator heated the metal surface, then quenched it with a special solution. The process imparted the temporary light green cast to the Sower that is now visible, and which will give way over time to the more familiar darker color.

When workers put the scaffolding around the sculpture, they had to move the aircraft-warning beacon at the Sower's feet to the top of the scaffold so it would be visible to pilots. When they lifted the light, they found stamped in the base the points of a compass that oriented the Sower in the direction it now faces. There were also instructions for workers installing the sculpture to attach a plumb bob to a small screw in the Sower's thigh. When the plumb bob hung directly over the intersection of the north-south and east-west lines of the compass, the sculpture would be standing perfectly upright.

The name of the artist, Lee Lawrie, was also stamped in the bronze at the base, and the name of an assistant was found on one of the Sower's toes.

Work in 2001 included rehabilitation of the tiled dome, which required replacing a few tiles near the gutters that had popped off when water entered the joints and froze. Workers also rebuilt the walls of the 14th floor observation deck, reglazed the windows of the curtain walls surrounding the Memorial Room on the 14th story, reglazed the five vertical strip windows that run from the sixth to the 12th floors on each side of the tower, and repointed each joint in the limestone skin of the entire tower.

Reconstruction of the corner turrets at the 14th floor, where the building's floor plan changes from square to octagonal, was a major project in 2001. The turrets leaked badly from the day they were installed.

Copper flashing beneath the capstones was meant to carry water away, but the copper was full of three-cornered tears. Rindone speculated that they were made by the large capstones as they were being installed. The corners of these 2000-pound stones were sharp, and acted as spears when a stone bumped into the copper.

"You have to consider circumstances at that time." Rindone said. "At 270 feet in the air . . . with very little scaffold to hang onto, it was a struggle to control these large stones being lowered on cables in gusty, strong winds . . . these stones went where they wanted to go."

The remedy involved removal of capstones and five courses of limestone veneer immediately below the capstones, and cutting back 12 inches of brick back-up to create an air space for water

Louis Perschke, project superintendent for Mark 1 Restoration Company, inspects work at the south entrance, which includes partial replacement of original clay brick in the walls.

control. The remaining brick was then coated with stucco to create a smooth surface, to which a fully adhered rubber roofing membrane was attached. The membrane was covered with red rosin paper and topped with lead flashing before the wall and capstones were reinstalled.

These operations all went more or less according to plan. However, an unpleasant surprise at the buttresses cost more than three months delay and $1.7 million, which was funded by an additional appropriation (See photo on page 10.)

The buttresses are eight vertical masonry structures separating the tile "thunderbird panels" at the 18th floor, 320 feet above the ground. The original plan called for simply repointing the buttresses, but when workmen ground away the old pointing mortar they found they could move the stones. Limestone blocks were dangerously loose five courses down from the apex. "Those stones were directly above the 14th story observation deck, so there was a serious safety issue there . . . the buttresses needed to be reconstructed and stabilized." Rindone said.

The scaffold on that part of the building was not designed to hold much stone, so the contractor fashioned a jib, a small crane, to move the stones to the 18th floor walkway. Workmen dismantled each buttress, replaced the soft brick core with concrete brick, and then reinstalled the limestone veneer. Each buttress was tied to its new core with bronze strips and bronze pins. "These things won't go anywhere anymore," Rindone said.

Work in 2002 included repointing of the fifth floor balcony walls, and repointing the outer walls of the three-story base. When workers ground out the old pointing mortar in the northeastern portion of the base, they found that the limestone veneer had been inappropriately installed. Instead of placing each stone on a full bed of setting mortar, the masons just troweled a few globs of mortar near the edges, leaving large voids under the center of the blocks.

The defect was hidden with pointing mortar, which eventually shrunk and cracked. Driving rain went through the old pointing mortar, through the voids, into the brick back-up and saturated and damaged interior plaster finishes. That was common throughout that part of the building, according to Rindone.

"The idea that this entire building was built perfectly is inaccurate. You had some people who didn't do a good job and some people who did. In this particular case, whoever placed those stones in that area got away with doing marginal work," he said.

The summer of 2002 also saw the beginning of work on the south entrance, where two driveways lead to an underground loading dock. Portions of the two massive outer walls will be rebuilt, including partial replacement of their brick cores. The two inner walls will be drawn together with eight large stainless steel rods, threaded and equipped with huge nuts. Stairs and stone balusters that flank the pedestrian entrance will be dismantled and reconstructed with appropriate waterproofing and flashing to control water infiltration.

Work at the south entrance is scheduled to run through 2004, according to Rindone. Work at the east entrance is scheduled to begin in 2005, and the west in 2006. Other remaining work includes rehabilitation of the four interior courtyards in 2007 through 2010, window rehabilitation in the base and stabilization of the vaulted Guastavino tile ceiling at the south loading dock in 2010, and replacement of the copper roof on the base, 2011 through 2014.

Replacement of the copper roof on the base is especially critical, according to Rindone. The roof is 2½-half acres of 30-inch-by-33-inch copper sheets tabbed and soldered together, and has endured 70 years of expansion, contraction and hail damage. "There are sections of the roof being held down with sandbags . . . I wouldn't want to be around here in a high wind if those sandbags were

Stone displacement at the south entrance is typical of that found in walls elsewhere on the capitol. Workers in the background are repointing the south pavillion.

not there," he said. Fortunately, no one was around on an April weekend in 2001 when a 70-mile-per-hour gust peeled two tons of copper roof off the eastern leg of the southeastern quadrant and left it draped on the second-floor promenade.

Obviously, the original eight-year timetable no longer applies. "The problem is that the study done in '95 did not address some of the things that we're having to do now, such as the work at the south entrance, rehabilitation of windows, work on the east and west entrances, and repointing all of the structure instead of just 25 percent," Rindone said.

A $500,000 Save America's Treasures Grant will be applied to the south entrance project, according to Rindone. "We've had to steal from Peter to pay Paul by moving money from later in the restoration and using it to do this extra work . . . but we're trying to stick to that original $20.6 million appropriation." At some point, however, the restoration effort is bound to run out of its initial appropriation before it runs out of things to fix, hopefully sometime after the recovery of the state's economy and its budget.

But Roxanne Smith, longtime tour guide at the capitol and sometimes called "Mother of the capitol," has been watching public reaction to the restoration work and is not worried. "The restoration seems to give Nebraskans a sense of ownership in the building," she said. "Mike [Rindone] will tell you that masonry buildings need repointing now and then, so every 70 years, a generation of Nebraskans is privileged to make sure that this building is preserved."