SUMMARY: It was an eventful summer of 2010, beginning with a setback on the arcade project due to the settlement of one of the seven supporting piers, and culminating in a dust-up over the dusting of the interior of the church. As a preface to the details which follow is a copy of an e-mail message to Austin Nuñez, the chairman of the San Xavier District of the Tohono O’odham Nation, who toured the Mission with Jim Pyers, Danny Morales and Bob Vint on August 26, 2010, to learn about the work being done by the Patronato.
Subject: San Xavier
Date: Tues, 31 Aug. 2010 9:44 AM
From: bob@vintarchitects.net
To: ”Austin G. Nunez”
Hi Austin – A visual reminder of how the east tower is in need of stabilization and refinishing! It’s something to remember that were it not for the work that the Patronato has organized, the Mission by now would be an unsafe structure – with large chunks of concrete from the 1950s falling from the cornices, and plaster falling from the ceiling inside, making it such a dangerous building that it would have to be condemned and fenced off to keep the public away and out of danger. The Mission is in essence a large sculpture that has been standing in the weather for over two centuries – and things fall apart, unless they are maintained and put back together.
Bob
September 16, 2010
(A.1) 6.10.10 SITE MEETING (8:00 a.m., 75º, clear)
PRESENT: B. Vint, Ralph Pattison, D. Morales, MRB crew
[Sonny, Vince, Jorge, Santiago, Freddy, Alex]
WORK IN PROGRESS: Excavation of earth around pier bases to level of bearing on caliche.
DISCUSSED: The stones below grade appear to include smooth river cobbles, along with the fractured sharp-edged volcanic basalt of the upper portions of the piers and elsewhere in the building. The mortar has disintegrated and some mortar joints appear to be just dirt. The geo-technical engineer Ralph Pattison recommended that the bases of the piers be restrained with a concrete footing that would in effect underpin the bases of the piers. Ralph sent his recommendation by e-mail the following day – by which time Pier #4 of 7 had settled as described below. Morales called Vint (in San Fran CA) by cell phone to inform him and both agreed to meet Monday afternoon as soon as Vint returned to Tucson. Vint informed the Patronato construction committee of the problem by e-mail (Jim Pyers & David Carter)
Subject: San Xavier
Date: Fri, 11 Jun 2010 2:13 PM
From: ralphmpattison@aol.com
To: bob@vintarchitects.net
Bob; Here are two pictures from yesterday. I’ll send the rest later.
I am somewhat uneasy with the extent to which the arch column footings have been undermined during the repair process. Unless Danny Morales has a good reason to avoid using concrete, I’d like to see it placed as soon as possible into the below-grade crevices of each column. I think concrete would be faster and stronger than his lime-mortar technique. Your suggestion of a “bridge mix”, a flowable mix with pea gravel aggregate and a high cement-to-water ratio, makes sense. If feasible, the entire excavation below grade could be filled with this mix, taking care to force the mix into all crevices.
Thanks,
Ralph
(A.2) 6.15.10 SITE MEETING (2:00 p.m., 95º, clear)
PRESENT: B. Vint, David Carter, D. Morales, MRB crew
[Santiago Gomez, Freddy Garcia, Jorge Gomez, Vincent & Sonny Morales]
WORK IN PROGRESS: None at present. – Vint & Carter on-site to inspect settlement of Pier #4.
DISCUSSED: Shoring of arches on each side of Pier #4 – all appears to be stable and well-shored. Morales reported that the pier settled suddenly as his son Vincent was rinsing the base in preparation for re-pointing. The settlement was vertical (i.e. not out of plane) and approx. 1-½” – 2”. Vint measured cracks at 1” wide in surface of arches. Assessment is that bearing lines of force have not been disrupted and the arches can be repaired in place. Attached memo summarizes my assessment of conditions after the settlement occurred. It was agreed that the concrete underpinning would proceed at once. Since concrete is liquid and exerts a force when it’s poured it was decided to place the underpinning in two lifts (or pours), the first approx. 6”– 8” thick to engage the lower stones of the pier bases without pushing them out of place, and a second layer poured over the top once this has set for an additional thickness of 12”. Per Pattison the concrete shall be a floawable bridge mix, 4000 psi, reinforced with #5 bars (5/8”diameter) spaced at 12” on center (OC) maximum and looping around each pier base. The two pours shall be dowelled together with #5 vertical bars at 12” OC staggered. Danny additionally suggested placing volcanic cobbles in the surface of the first pour while the concrete is freshly poured to further key the two pours into one. Note: use of concrete below grade for structural underpinning is accepted in preservation practice because it does not form a coating that could trap moisture. The hardness of concrete is compatible with that of stone.
6.15.10 Pier # 4 as shored after settlement. Crack that opened as result of settlement of stone pier (approx 1” W).
6.15.10 D. Carter inspects cracks@ arch above Pier #4. 6.22.10 Danny demonstrates retaining effect of footing.
(A.3) 6.22.10 SITE MEETING (9:00 a.m., 90º, clear)
PRESENT: B. Vint, V. Lamplot, B. Fontana, D. Morales, MRB crew
[Santi Gomez, Fred Garcia, Jorge Gomez, Alex Tracy, Vincent & Sonny Morales]
WORK IN PROGRESS: Stabilization of pier bases [Vince, Freddy, Santi & Sonny]
DISCUSSED: First stage of concrete underpinning is complete. Bases of piers are stabilized. Next pour will be scheduled for Thurs. or Fri. of this week. Danny has batch ticket from concrete truck specifying 4000 psi mix. Discussed procedure for repairing adobe masonry in place: additional shoring will be required. Adobe will need to be re-toothed and crack stitched back together.
6.22.10 After first concrete pour for underpinning.
7.6.10 After2nd concrete pour w/base for new CMU pier. Arch above pier # 4.
7/6/10 Danny Morales, Bunny Fontana and Vern Lamplot survey stabilization work on pier #4.
7/7/10 Vince repoints base of Pier #4 7/7/10 Crack @ arch north ofPpier #4
7/7/10 Adobe wall of museum w/adobe foundation.
7/21/10 Lightning struck cross over weekend.dislodging lightning. rod- Morales’s now reinstalling. Cross itself remained anchored, i.e. lightning protection system worked to conduct charge to ground.
7/22/10 Base of pier# 2 note nix of rubble stone & brick. 7/22/10 Pier 4 fully shored after 2nd concrete pour.
7/28/10 Area of work is well secured. Condition of ocotillo & other plants indicate a healthy monsoon season.
7.28.10 Lisa Morales high in the Sanctuary, cleaning the RetabloMayor. Heat & humidity are both high in the vault.
7.28.10 Freddy García re-points Pier #5
7.28.10 Pier #4; over the years, water coming down the face has eroded the brick & mortar.
View of stone foundation @ right angle to arcade; Vint thought this might be from original Kino chapel.
9.8.10 Fontana reads the evidence of why this cannot possibly be the foundation of Kino’s chapel.
END OF REPORT