ONARCHITECTURE- Shabby slab? Old Mall studies raise new questions
A pair of recently discovered Mall studies say the heaving bricks are the result of the failing concrete slab beneath them.
FILE PHOTO BY DAVE MCNAIR
For months, the debate over the $7.5 million renovation of the Downtown Mall was all about the heaving bricks. But a pair of recently discovered studies say the real problem is what lurks beneath.
In 1989, locally-based Wood, Sweet, & Swofford Architects was commissioned to study the Mall's condition and develop a design plan and renovation strategy, and was again engaged 10 years later for the same purpose. In both studies, the architects determined that the mortar bed beneath the bricks had deteriorated due to freeze-thaw damage, and recommended removing the existing mortared brick pavers and replacing them with bricks set in sand.
The firm also recommended replacing the concrete accents with granite ones, using mortared brick pavers along expansion joints and drainage areas, updating the mechanical and electrical equipment, and phasing the project over a number of years– virtually the same recommendations made in a City-funded study in 2005, and nearly identical to the renovation plan that was recently approved, with the exception of the construction phasing, which instead of years has been reduced to five months.
So why did the City buy a new study after WSSA had issued reports on what the problem was and how to fix it?
Architect Don Swofford of WSSA thinks some information he presented was information the City may not have wanted to hear. Namely, that that the massive concrete slab beneath the bricks might need to be completely replaced.
In 1989, WSSA suggested that the slab was showing signs of damage due to drainage and moisture problems that were causing it to settle. A contractor in charge of maintaining the Mall was interviewed, and he said that the slab was occasionally found to be broken where such settling had occurred. Further examination of the slab was outside the scope of the 1989 study, but it was recommended that it's soundness be verified. However, by 1999, WSSA was calling the concrete slab the Mall's "biggest problem."
Ten more years of poor drainage and moisture seeping through the crumbling mortar between and beneath the bricks had begun to take its toll. In addition, there was concern about the damage the moisture seepage might be inflicting on the metal rebar within the slab.
As evidence of slab failure, WSSA cited the cracked and shifting bricks, which the firm called "typical of subsurface heaving" and noted that the condition of the bricks had become noticeably worse since they had last studied them in 1989.
"The slab will need to be inspected, and possibly, replaced," the 1999 study determined.
As for the bricks themselves, such a hot topic in recent months, the WSSA study was less concerned with their size (they make no recommendation about what size bricks to use) than with their bulk. Calling them "too strong, too big," they determined that the "spalling" and "breaking apart" that was occurring was being caused in part by their sheer mass. Indeed, a Hook reporter recently lifted and replaced a loose brick on the Mall, and was surprised by how thick and heavy it was. Swofford, in joking, refers to them as "Roman-like bricks," which he says were not made for mortared joints. "The spalling and exfoliation of the brick was due to the mortar strength not being matched properly to the brick," he says.
As for the slab, eight years later Swofford appears to have no doubts about its condition. "My impression from our past research is that the slab will need to be replaced, potentially in its entirety," he says.
However, based on information in the 2005 Wallace, Robert, & Todd study, specifically the engineering part of study that determined the slab was in good condition, City planners have repeatedly assured the public, City Council, and the Board of Architectural Review that the concrete slab is in good condition.
Re-presented with the WSSA findings, and asked if City planners are sure the concrete slab is in good condition, City spokesperson Ric Barrick, speaking on behalf of the MMM Design Group, designers of the brick replacement project, acknowledged that some slab damage might be encountered, but said the City is "confident that whatever limited repair work that needs to be performed on the slab will be possible in our time frame."
"We will remove the bricks, assess the slab, and repair any damage as we go, with a contractor who can handle it and is skilled in various repair and construction tasks," says Barrick. "If plumbing or slab repair work is necessary, they will be able to take care of it before the new bricks are scheduled to be placed."
But Bill Letteri, who was head of the City's facilities management department when both the WSSA and WRT reports were done (he now works for the County in a similar capacity), says only sample tests on the slab were done during the WRT study, and he say's he'd be surprised if they didn't find significant damage.
Given his experience with the moisture problems the Mall has experienced over the years, Letteri is not optimistic about what contractors will find once they pull up the bricks. "They may well find that entire sections of the slab are damaged," he says.
Letteri also said that the proposed five-month timetable for the project struck him as optimistic, an opinion shared by others as well.
Indeed, both the WSSA and WRT reports recommend phasing the project over a number of years, but under pressure from the Downtown business community, who want the project done as quickly as possible, those recommendations were ignored.
"This schedule was largely a product of intense discussion with mall businesses," says Barrick, "who pushed us for a quicker and less disruptive process."
Barrick believes the five month schedule is reasonable. "Originally, the project was gong to be done with only one crew, but we are planning on using four crews," he says. Barrick also points out there will be some prep work done this fall, such as renovating the drainage runnels and the bricks that directly butt up against the buildings.
However, some Mall business owners are skeptical.
"They want to get it done in May– May of what year?" said Men & Boy's Shop owner Mike Kidd, who was around for the original Mall project. "Once a project like this gets started, you can't stop it. I wish them all the best, but if they get it done in that time frame, it will be a miracle."