B08_Attach_4_Sperry_Chalet_-_ANA_Testing_Final_Report_09-06-18.pdf

Atkinson-Noland & Associates

2619 Spruce Street Boulder, CO 80302 303.444.3620

32 Old Slip, 10th Floor New York, NY 10005

917.647.9530 ana-usa.com

REPORT

MASONRY EVALUATION

Sperry Chalet Glacier National Park Montana

PREPARED FOR:

Anderson & Hallas 714 14th Street Golden, CO 80401

PREPARED BY:

Michael Schuller, P.E.

Atkinson-Noland & Associates, Inc.

Sperry Chalet Final Report ANA Job No. 18-046

September 6, 2018

Table of Contents

1. Introduction

2. Condition Survey

2.1 Digital Photography

2.2 Fire Intensity

2.3 Stone Masonry Wall Conditions

2.4 Stone Pier Conditions

3. Investigative Testing

3.1 Nondestructive Evaluation: Microwave Radar Scanning

3.2 Nondestructive Evaluation: Pachometer Scans

3.3 Videoscope Evaluation

4. Material Tests

4.1 Retrofit Anchor Tension Strength

4.2 Retrofit Anchor Shear Strength

4.3 Mortar Chemical Analysis

4.4 Mortar Petrographic Analysis

4.5 Stone Samples

5. Discussion and Recommendations

5.1 Fire effects

5.2 Wall Sections

5.3 Concrete Lintels

5.4 Retrofit Anchor Tension and Shear Capacity

5.5 Recommended Mortar Formulation for Repointing and Rebuilding

5.5 Recommended Masonry Strength Values

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1. Introduction The historic Sperry Chalet, located in Glacier National Park, was damaged in a fire in August 2017.

A program is underway to stabilize and rebuild the Chalet with floor and roof construction ongoing. This report presents observations, results of nondestructive and in situ testing conducted on site, and laboratory tests carried out on mortar samples removed from interior and exterior masonry construction.

Atkinson-Noland engineer Michael Schuller was on site July 10 through July 13, 2017, to complete the work. Others on site and providing assistance included personnel from Dick Anderson Construction, Anderson & Hallas, JVA, Martin/Martin, and Yeh & Associates.

Typical results are included in the body of this report. Photographs showing all interior and exterior elevations are included in Appendix A, field notes including all radar scanning locations are included in Appendix B, images of all radar scans are included in Appendix C, and mortar petrographic analysis results are included in Appendix D. Information contained herein will be used by the design team for designing retrofit and repairs.

See the Discussion section at the end of this report for conclusions and recommendations regarding material properties and repairs.

2. Condition Survey

2.1 Digital Photography

All interior and exterior wall surfaces were photographed using a digital camera for documentation purposes. Individual photographs showing wall elevations are included in Appendix A. Photographs of tests, sample removal areas, and typical conditions are included throughout the body of this report.

2.2 Fire Intensity

High temperatures are damaging to metals and cementitious materials such as concrete and mortar.

Effects of high temperatures on stone is less well-known, although thermal differentials that occur during severe fires are known to cause damage in the form of cracking and delamination. Information critical to understanding high temperature effects are the peak temperature experienced by construction materials and the duration of the fire. Both of these parameters combine to provide an indication of the depth to which wall and lintel materials are affected.

Construction materials including metals and glass soften and melt at defined temperatures. Samples of melted or deformed lead, aluminum, and glass were present throughout the site. Steel and iron components were also present and appeared to be unaffected by fire temperatures. As shown in Figure 1, these observations suggest a maximum sustained fire temperature of between 1,350 and 2,100º F.

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Concrete, mortar, and other cementitious materials are also visually affected by high temperatures, changing color from gray, to a subtle pink color, to white gray, to buff, as the temperature exposure rises.

As seen in Figure 2, the exterior of many concrete lintels is a buff color, suggesting maximum fire temperatures in excess of 1,700º F. Concrete had spalled to a depth of 1 ¼ inch at this location, with the outer ¼ inch being buff colored, and concrete beyond 1 inch deep being a light pink color. For concrete with siliceous aggregate, the observed depths of color effects suggest a high temperature duration of 1 ½ to 2 hours.

In addition to visible alterations, high temperatures have an effect on strength of cementitious materials and internal reinforcement. Reinforcing bars retain 65% of their yield strength at 1000º F, with the yield strength dropping to 15% of original strength at 1400º F. Similarly, concrete retains 60% to 90% of its strength up to 1000º F, dropping to 50% at 1400º F.

Mortar materials did not appear to be significantly affected by high temperatures and remained hard to very hard and moderately to well-bonded throughout. Mortar did not undergo an apparent color change.

Mortar petrography suggests that, where samples were removed, mortar was subjected to a maximum temperature of less than 1000º F.

Figure 1. Observations of fire effects on metals and glass suggests a fire temperature between 1,350 and 2,100º F.

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Figure 2. Changes in concrete color suggest a fire temperature in excess of 1,700º F having an effect on concrete to a depth of greater than 1 ½ inch.

2.3 Stone Masonry Wall Conditions

Stone walls are built of multiple leaves, with different stone sizes, mortar joint widths, and coursing at the interior and exterior wall faces. Units at the exterior are massive with rough natural surfaces proud of the wall face and wide mortar joints (Figure 3). Units at the interior wall face are smaller with thinner mortar joints (Figure 4). Measurements of minimum, maximum, and typical stone and mortar joint dimensions are included in Table 1 and Table 2.. Variations in stone thickness at interior and exterior leaves was measured with radar scanning as discussed later in this report.

Figure 3. Exterior east wall. Folding ruler included for scale.

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Figure 4. Interior east wall. Folding ruler included for scale.

Table 1. Measurements taken at the exterior, east wall.

Feature Minimum Maximum Typical Stone face size 4” x 12” 24” x 64” 16” x 24” Mortar head joints ½” 4” 1 ½” Mortar bed joints ¼” 4” ¾”

Table 2. Measurements taken at the interior, east wall.

Feature Minimum Maximum Typical Stone face size 2” x 5” 12” x 26” 9” x 16” Mortar head joints ¼” 2” 1” Mortar bed joints ¼” 1 ½” ¾”

Mortar hardness was evaluated subjectively throughout by scraping with a metal tool. Mortar was observed to be very hard throughout, with no significant widespread deterioration. The outer ¼ inch of mortar was detached or separated at locations of severe fire damage.

Overall stone condition was evaluated throughout the building interior and exterior using a combination of visual observation and sounding with a small-diameter sounding hammer and a mason’s hammer (Figure 5). Stone throughout most of the interior shows some damage related to heat intensity and thermal differentials as discussed above, and it is estimated that more than 75 percent of interior stone surfaces shows some level of damage. Stone surfaces are detached, separated, and flaking, and can be removed with little effort (Figure 6). In many cases sounding with a small-diameter tapping hammer was sufficient to separate and remove the stone face. At some locations, notably the east chimney and portions of the east wall, stone damage exists to a depth of greater than 2 inches (Figure 7).

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Figure 5. Sounding to detect stone delaminations; stone face delamination is visible at window jamb on right.

Figure 6. Stone delamination, easily separated by probing with a metal ruler.

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Figure 7. Stone face separation 2” thick, east wall.

Figure 8. Stone face cracks appearing at some locations.

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Figure 9. Stone delamination at some areas extends to a depth of 3 to 5 inches. Base of north chimney shown at left, interior east wall shown at right.

Figure 10. Occasional stones are disaggregated and crumbling (west wall).

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Figure 11. Left: occasional stone damage exists at some window openings (exterior, east wall).

Right: exterior stone at most areas is intact with no significant damage (exterior, west wall).

Stone condition was mapped as it relates to potential repair approaches are depicted in field notes showing stone condition included here as Figure 13 and also shown in Appendix B. Areas with no distress or minor distress are highlighted yellow, moderate damage is shown as orange, and significant damage is shown as red according to the legend included as Figure 12.

Figure 12. Stone condition survey legend for Figure 13.

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Figure 13. Stone condition survey. See also field notes, Appendix B. Base drawings by Anderson and Hallas.

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2.4 Stone Pier Conditions

Condition of foundation piers at the building interior and exterior (west) porch were mapped based on visual observations as shown in Figure 14. Pier condition ratings were based on the expected repair effort as follows:

1. Yellow = good condition, minimal or no repairs

2. Orange = fair condition, repairs limited to minor mortar repointing, picking and cleaning stone spalls.

3. Red = poor condition, with some stone replacement and/or rebuilding required.

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Figure 14. Masonry pier condition survey following the legend above and discussion in the text. See also Field Notes, Appendix B.

Legend Good condition Fair condition Poor condition

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3. Investigative Testing

3.1 Nondestructive Evaluation: Microwave Radar Scanning

A GSSI SIR-3000 radar unit with a 1500 MHZ antenna mounted in a wheeled trolley was used to scan stone masonry walls (see Figure 15). The system was calibrated based on a strong reflection from the back side of stones with known thickness at window sills. Horizontal and vertical radar scans were conducted throughout the interior and at some exterior elevations to investigate internal wall construction and map reinforcement in concrete window lintels. A total of 30 radar traces were recorded and analyzed in the office. Locations of saved radar scans are shown in field notes in Appendix B, and all radar scans are shown graphically in Appendix C.

Figure 15. Surface penetrating radar scanning (assistance by JVA).

Radar Scans: Stone Walls Radar scans were carried out at the exterior west elevation (1 loc.), interior west elevation (2 loc.), interior east elevation (1 loc.) and interior south elevation (1 loc.); specific scan locations are included in Field Notes in Appendix B. A typical scan is included in Figure 16 with identifiers describing interpretation. For this scan, the interior stone wythe ranges from 5 to 11 inches thick and the outer stone wythe ranges from 7 to 10 inches thick.

The space between the stone leaves is filled with mortar and rubble to a thickness of zero to 8 inches. A similar wall section is shown in Figure 17; at this location the stone leaves are thinner and the interior mortar/rubble core is up to 12 inches thick.

No significant interior voids were observed at wall scans, although many small separations and delaminations exist at the back of stones. These voids are estimated at a maximum thickness of 1 inch and exist over approximately 10 percent of the wall area. No internal reinforcement was detected at any of the wall scans.

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Also important to note is that no significant stone damage was observed beyond a depth of approximately 2 inches. Stone at depth within the wall section appears to be intact.

Figure 16. Radar scan 007, horizontal scan, interior of west wall, 2nd floor.

Figure 17. Radar scan 0023, vertical scan from interior of east wall.

A series of radar spot scans were carried out at a portion of the north wall at the northeast building corner to document stone thickness at each wall face. Results of these surveys are included in as maps showing relative stone thickness with different color ranges as shown in Figure 18. Results show that, in general, stones used at the

Pg. 14 9/6/2018 exterior face are thicker than those used at the interior face, and, although there are no true through-wall bond stones, the varying stone thickness provides some level of bonding between outer and inner wall leaves.

Figure 18. Stone thickness determined by radar scanning.

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Radar Scans: Concrete Lintels Concrete lintels at the north elevation (2), east elevation (1), and west elevation (1) were scanned with radar.

Radar scans were augmented by pachometer scans at the 4 listed lintels and at 9 additional lintels. Of the 13 concrete lintels evaluated, internal reinforcement was detected at only 2 of the lintels. The other 11 lintels were unreinforced. The two reinforced lintels had a single longitudinal bar, roughly centered on the lintel height and depth.

A sketch of the concrete lintel at the north elevation is shown in the Field Notes, Appendix B. The lintel measured approximately 7.5 inch square with a single bar at a depth of 4 inches. The longitudinal bar did not extend the full length of the lintel, beginning 13.75 inches from the west end of the lintel. At some locations, the exterior stone extends into the concrete lintel, see Figure 19.

Figure 19. Stones at some window heads extend beyond exterior concrete lintel face.

3.2 Nondestructive Evaluation: Pachometer Scans

An eddy-current pachometer was used to supplement radar scanning at concrete window heads. A total of 13 lintels were scanned with the pachometer; 2 lintels were found to be reinforced; all other lintels scanned contained no internal reinforcement.

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3.3 Videoscope Evaluation

Observations of wall interior and mortar joint solidity were made at several locations; see photographs in Figure 20 and Figure 21. At some locations interior conditions were observed directly at missing stones or mortar voids.

Head joints and bed joints had occasional voids behind pointing mortar, as shown in Figure 20.

Internal wall condition was observed at 2 locations. At the south wall, near the foundation, a void measuring 1” x 5” x 6” was observed at a location with a strong radar reflection at the back of the stone. Approximately 10% of stones scanned had similar strong reflections indicative of narrow voids, rather than mortar fill, behind facing stones.

Internal wall conditions were also observed at the core removal location at the west wall. As shown in Figure 21, the wall has variable fill behind the interior stone leaf. Stone is solid and unbroken, with voids and rubble fill seen at the bottom of the core hole. Mortar at the top of the core hole is solid and has intimate contact with stone throughout.

Figure 20. Void head joint behind 1” pointing mortar.

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Figure 21. Internal wall conditions at east wall core hole.

Voids and rubble fill

Solid fill

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4. Material Tests

4.1 Retrofit Anchor Tension Strength

Five total anchors were installed for testing to determine anchor tension capacity. Anchors were installed to meet project design requirements as follows.

• Anchor locations followed project design requirements, with a spacing of 18 inch ± and staggering anchors 1 ½ inch above and below the 2nd floor ledger centerline. Some anchors were moved 2 to 3 inches off the design alignment to miss log embed pockets. Anchors were installed into stone, mortar, and at locations where the wall surface was rough. See below for photographs of each test location.

• Tension anchor dimensions: ¾” diameter threaded rods, pre-bent at 22.5º with 13 inch embedment.

• Installation in 1” diameter holes drilled into stone and mortar. Initial hole drilling used a hand-held core drill with very slow progress (2” core depth in 25 minutes). Holes were finally drilled using a hammer drill with 1” bit.

• Holes were cleaned with a combination of air pressure and brushing to remove all drilling dust.

• Screen tubes were inserted into holes.

• Screen tubes were filled with Hilti HIT HY-270 epoxy adhesive. Note that Hilti is phasing out the HIT HY-

70 adhesive noted in project documents, replacing with the HY-270 product which has the same performance specifications as the HY-70 adhesive.

• Anchors were inserted in a twisting motion to the full anchor depth. The epoxy quantity used at approximately 1/3 of holes was as expected, indicating mostly solid conditions at the embedment. At 2/3 of the drilled holes, extra epoxy was required to get the expected squeeze-out at the wall face, indicating internal voids beyond facing stones.

• Adhesive was cured for 18 hours, minimum, and tests were carried out the following day.

• Anchors remained in place following testing.

Anchors were tested following the approach of ASTM E488, Test Methods for Strength of Anchors in Concrete and Masonry Elements; see Figure 22 for the typical test frame configuration. Anchor installation conditions and test results are listed in Table 3. Anchors were loaded to maximum load or when cracking was observed. No explosive brittle failures were observed.

Load-displacement plots for each tension anchor test are shown below. Anchor ultimate capacity is determined by the maximum applied load. For this case it is not reliable to base the anchor working load capacity on a displacement criterion: recorded displacements were greater than expected due to anchor flexure at the 22.5º bend. In addition, the wall surface roughness required wood shims that increased measured deflections.

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Figure 22. Anchor tension test setup, shown here at test location T2.

Table 3. Anchor tension pullout test results. All anchor installations were tested at an age of 18 hours; tests were located at the west wall, north end, 2nd floor ledger.

Test No.

Installation Conditions Failure Notes Failure Pressure

(psig) Failure

Disp. (in.)

Failure

Force (lb)

Fair installation, mortar recessed 1”, in bed joint

Cracking at stone below

2,050 0.268 4,950

Good installation into solid stone

Cracking at stone below

4,050 0.308 11,120

Poor installation, voids in mortar head joint, mortar recessed 1.5”

Cracking at epoxy around anchor, anchor disp.

2,500 0.552 6,870

Fair installation, in cracked stone, stone recessed 1”

Cracking at stone 1,800 0.310 4,950

Good installation, in bed joint near beam pocket

Stone cracking, anchor disp.

3,500 0.300 9,620

Average (lb.) 7,500

Standard Deviation (lb.) 2,780

Coefficient of Variation (%) 37%

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Figure 23. Anchor tension test 1.

Figure 24. Anchor tension test 2.

Figure 25. Anchor tension test 3.

10000

0 0.5

Fo rc e (lb

Displacement (in.)

Tension Test No. 1 Force vs. Displacement

T1 (a) T1 (b)

10000

0 0.2 0.4 0.6

Fo rc e (lb

Displacement (in.)

Tension Test No. 2 Force vs. Displacement

10000

0 0.2 0.4 0.6

Fo rc e (lb

Displacement (in.)

Tension Test No. 3 Force vs. Displacement

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Figure 26. Anchor tension test 4.

Figure 27. Anchor tension test 5.

10000

0 0.2 0.4 0.6

Fo rc e (lb

Displacement (in.)

Tension Test No. 4 Force vs. Displacement

10000

0 0.2 0.4 0.6

Fo rc e (lb

Displacement (in.)

Tension Test No. 5

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4.2 Retrofit Anchor Shear Strength

A total of four anchors were installed for shear testing using the same process and materials as described above except that shear anchors had an 8 inch straight embedment. Each anchor shear test requires installation of 2 reaction bolts and, to avoid disrupting visible masonry, anchors were installed at the crawlspace level. Anchors were installed into stone and mortar pockets.

Anchors were tested following the approach of ASTM E488, Test Methods for Strength of Anchors in Concrete and Masonry Elements; see Figure 28for a typical anchor shear test frame configuration. Anchor installation conditions and test results are included in Table 4. Anchors were loaded to maximum load or when cracking was observed.

No explosive brittle failures were observed.

Anchor shear tests were not entirely successful. Four tests were prepared and 2 tests were completed. At 2 locations the test rig would not fit properly due to stone surface roughness. Of the 2 tests completed, one test was halted due to stone detachment at one of the test frame reaction anchors at a load of 1,370 lb. with no distress at the test anchor. At the one valid test, the anchor resisted an applied load of 2,200 lb., ultimately failing by deflection near the wall face. The load-displacement plot for the single valid shear anchor test is shown below.

Anchor ultimate capacity is determined as the maximum applied load.

Figure 28. Typical shear test frame configuration.

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Table 4. Anchor shear test results. All anchor installations were tested at an age of 24 hours; tests were located at the west wall, south of center, at the crawlspace level.

Test No.

Installation Conditions Failure Notes Failure Pressure

(psig) Failure

Disp. (in.)

Failure

Force (lb)

Good installation in loose mortar fill

Test not possible due to test frame clearance

Good installation in center of mortar infill pocket

Test not possible due to stone roughness

Good installation, in center of stone

Failure at anchorage, pulling stone off wall.

No distress at test anchor.

500 (max applied)

0.552 1,370

Poor installation, good bearing, wall surface depressed 2”

Mortar crushing, anchor rotation

850 0.180 2,200

Average (lb.) 2,200

Standard Deviation (lb.) --

Coefficient of Variation (%) --

Figure 29. Anchor shear test 4.

0 0.05 0.1 0.15 0.2

Fo rc e (lb

Displacement (in.)

Shear Test No. 4

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4.3 Mortar Chemical Analysis

A total of 5 mortar sample were removed and shipped to the laboratory for analytical chemistry to determine binder:aggregate ratio, aggregate size gradation, and aggregate color. All samples were hard to very hard.

Sample locations and general condition are listed in the Figures below.

Figure 30. Mortar chemical analysis sample 1, east wall, interior, at deep stone spall. Mortar was hard but poorly bonded

Figure 31. Mortar chemical analysis sample 2, exterior, east wall, opposite mortar sample 1. Mortar was unbonded, below sill.

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Figure 32. Mortar chemical analysis sample 3, west wall interior, crawlspace. Very well bonded.

Figure 33. Mortar chemical analysis sample 4, west wall interior, 1st floor. Area of severe fire damage, moderately well bonded, outer ¼” was delaminated and loose in spots.

Figure 34. Mortar chemical analysis sample 5, west wall interior, 2nd floor. Area of severe fire damage, moderately well bonded to stone.

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Mortar Analysis Techniques Two analysis techniques were used. Chemical mortar examination followed the method described in Chemical Characterization of Historic Mortars by Middendorf, et al.1 This method is based on the use of acid digestion and chemical analysis to identify soluble silica resulting from portland cement hydration. Additionally, aggregate sieve analysis followed the requirements of ASTM C136, Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates. This method is based on the use of acid digestion of the binder and sieve analysis of the aggregate.

Table 5. Sample identification and location

Sample ID Location

East wall interior at deep stone spall, poorly bonded, 1” fill at head joint & void beyond

2 East wall exterior, below sill, unbonded

3 West wall interior, crawlspace, very well bonded

West wall interior, 1st floor, moderate bond, fire damaged, outer ¼” delaminated, loose in spots

5 West wall interior, 2nd floor, moderate bond, severe fire damage

Mortar Analysis Results The results of the chemical analysis and acid digestion of the samples are shown in Table 6. The binder component varies, depending on where the mortar samples were removed. Mortar Samples 1 and 2, removed from the interior and exterior of the east wall, are nearly identical with a minor lime component and volumetric proportions that approximate that of a Type M mortar. Results suggest that the same mortar was used throughout the entire wall thickness.

A significant lime component was detected at mortar samples 3, 4, and 5, which were removed from the crawlspace, 1st floor, and 2nd floor. Mortar sample 3 approximates a Type M mortar, whereas mortar samples 4 and 5 have formulations similar to that of Type S mortar. It appears that lime was added to mortar as construction progressed with upper levels.

All samples are undersanded. Samples 1, 2, and 3 contain slightly high sand components, (ranging from 1.9 to 2.3 parts sand). Samples 4 and 5 are moderately oversanded with a sand content of 1.2 to 1.6 parts. typical of common masonry mortars (about 1 to 2.). That is, the mortar has a high binder content in comparison with the sand content. These formulations would typically result in very high strength mortar. However, it could also result in significant shrinkage of the mortar materials, especially at wide joints. All of the samples were hard, 1 Middendorf, et al. Chemical Characterization of Historic Mortars. State-of-the-Art Report of RILEM Technical Committee 167-COM:

Characterization of Old Mortars with Respect to their Repair. RILEM Publications SARL, 2004.

Pg. 27 9/6/2018 relatively difficult to crush, and contained a significant portland cement component that contributed to the amount of detected soluble silica.

The aggregate gradation curves, plotted in Figure 35, show that the aggregate from all the samples had a greater amount of course aggregate than permitted by ASTM C144, Standard Specification for Aggregate for Masonry Mortars. Sample 1, 3, and 5 had a greater amount of course aggregate retained on the #4 through #30 sieve.

Sample 2 had a greater amount of course aggregate retained on the #4 through #16 sieve. Out of all the samples, Sample 4 generally met the ASTM C144 gradation range except for some coarse aggregate retained on the #4 and #8 sieve. Tests indicate that sand used for restoration mortar should incorporate additional coarse aggregate, compared to that required by ASTM C144 masonry sand, in order to match the original texture.

The aggregate size distribution and colors are shown in Figure 36. Ideally, the aggregate for the replacement mortar should match the color and gradation of the existing aggregates. Trial mixtures may be required to produce a repair material that matches the original with respect to color and texture.

Table 6. Results of chemical mortar analysis

Sample ID Volumetric Ratio Binder:Aggregate Ratio, by volume Portland Cement

Lime Aggregate

1 1.0 0.3 3.0 1:2.2 2 1.0 0.3 3.1 1:2.3 3 1.0 0.8 3.4 1:1.9 4 1.0 1.7 3.2 1:1.2 5 1.0 1.2 3.5 1:1.6

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Figure 35. Aggregate distribution by sieve size for mortar samples.

Sieve Size: 4 8 16 30 50 100 200 Pan

Figure 36. Aggregate distribution and color for mortar samples.

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4.4 Mortar Petrographic Analysis

Two mortar samples were removed and shipped to the laboratory for petrographic and chemical analysis following the method of ASTM C1324 to determine binder type (lime, portland cement, or natural cement) and overall quality. One sample was removed from area of heavy fire damage at the north wall interior, and a second sample from an area of minor fire damage at the west wall interior. Photographs of sample removal locations are shown below.

Figure 37. Mortar petrographic analysis sample 1, north wall at an area of severe fire-related distress. The outer 3/16” of the mortar joint was already fractured and fell off; the rest was very well bonded to stone.

Figure 38. Mortar petrographic analysis sample 2, west wall at an area of minor fire effects. Mortar was very hard and very well bonded to stone.

Petrographic analysis found there to be no damage characteristic of exposure to high temperatures. The absence of significant cracking, microcracking, discoloration, or calcium hydroxide dehydration suggests that the maximum temperature exposure at these locations was likely less than 600ºF and did not exceed 1000 ºF.

Mortar chemical tests conducted as part of the petrographic analysis found there to be no significant hydrated lime component with a binder:aggregate ratio ranging from 1.0:1.8 to 1.0:2.0. Mortar was undersanded with a

Pg. 30 9/6/2018 high portland cement content, similar to that of a Type M mortar. These results are similar to analytical chemistry results reported above.

The full mortar petrographic report is included in Appendix D.

4.5 Stone Samples

Two stone samples were removed by core drill with a diamond bit. One of the 2-inch diameter cores was removed from the interior east wall, at a location that will be covered by a future interior shear wall. This stone sample is retained for future tests, if needed. One bedrock core sample was removed from the interior floor west of the north chimney; this sample was retained for testing by Yeh and Associates.

Figure 39. Stone bedrock sample (assistance by JVA and Yeh and Associates).

5. Discussion and Recommendations

5.1 Fire effects

Site observations suggest the peak fire temperature ranged from 1,700 to 2,100º F. Mortar analysis suggests that at some areas the peak temperature exposure is estimated to be less than 600 to 1000ºF. At the upper temperature range concrete materials will have lost a significant portion of their strength to a depth of at least 1 inch. Concrete materials should not be considered for structural resistance to a depth of at least 1 inch from the interior surface. It did not appear as if high temperatures penetrated to a depth of greater than 2 inches into concrete window headers and internal reinforcement likely retained its full strength through the fire.

Mortar did not appear to be significantly affected by high temperatures. At some areas, the outer ¼ inch of mortar was loose and debonded, but mortar remained hard throughout with no apparent color changes.

Conservatively, mortar within 2 inches of the interior wall face should be neglected for resistance of structural loads. If this approach is followed, any loose mortar should be removed using hand tools, but it is not necessary to repoint joints for structural reasons.

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Open cracks should be repointed, and it may be desirable to repoint mortar joints for architectural purposes.

Mortar removal using hand tools will be very difficult and we suggest permitting angle grinders with diamond blades. Mortar should be removed to a depth of 2 times the joint width, or 2” considering a typical mortar joint width of 1” at interior wall surfaces.

Stone units were affected throughout, with many areas having the outer stone face delaminated to a depth of 1 to 2 inches. Stone within 2 inches of the interior wall face should be neglected for resistance of structural loads. Note that condition surveys above the 6-foot level were based primarily on visible observations with spot checks from ladder and scaffold. With close-up inspection it is likely that stone damage may be deeper and more extensive than visibly apparent at many areas.

Maps of stone distress were developed based on potential repair approaches (see Figure 13) as described below.

• Minor distress, 0 to ¼ inch stone loss: no remedial work; pick and clean loose stone.

• Moderate damage, ¼ to 1 inch stone loss: pick and clean loose stone, retool stone face to match adjacent, gradually easing transitions from areas of deep loss to shallow or no loss. The finished stone surface should be tooled to match its original texture.

• Significant distress, greater than 1” stone loss: remove delaminated stone faces, replace, patch, or install new stone faces as dutchman to restore the original profile.

Some isolated stones at the interior and exterior are loose and should be removed and reset in new mortar or anchored back to the wall mass for stability. Where anchors are installed through the stone face, finish the anchor hole using a stone plug or with patching mortar to match stone color and texture.

Condition of foundation piers at the building interior and exterior (west) porch were also mapped based on the expected repair effort as shown in Figure 14. Potential repair approaches for masonry piers are listed below:

• Good condition: minimal or no repairs

• Fair condition: repairs limited to minor mortar repointing, picking and cleaning stone spalls.

• Poor condition: some stone replacement and/or rebuilding required.

5.2 Wall Sections

Results of site observations, photography, radar scanning, pachometer scans, and videoscope examinations were used to develop representative wall sections. The wall sections shown below are based on nondestructive tests at the north wall near the northeast building corner. Sections shown in Figure 41 provide an accurate representation of stone coursing, based on photographs at interior and exterior surfaces, and of stone thickness, based on radar measurements (reference Figure 18). Interior rubble fill conditions and voids are schematic representations of overall observations and testing results.

Walls were well-constructed and are generally solid, with occasional mortar joint voids and voids at the rubble fill between leaves. A regular, continuously-filled concrete core does not exist, and the space between inner and outer leaves is filled with mortar and rubble stone. Bonding is fair, with stones regularly overlapping into the inner rubble core but few to no through-wall bond stones. Based on site observations, it would be prudent to install retrofit anchors to augment connection between wall leaves and enhance monolithic action for response to structural loads. Anchors connecting stone leaves should be min. 3/8” dia. stainless steel rods in ½” diameter

Pg. 32 9/6/2018 holes, set in epoxy with screen tubes. Place anchors within 12” of openings, tops of walls, and wall terminations and at 4’-0” on center each way. For this case, with very hard mortar, anchors are best installed at mortar joints rather than through the stone face.

Figure 40. Section cuts for wall sections below.

Section A-A Section B-B

Figure 41. Wall sections. Coursing and stone thickness is true, based on actual dimensions at each section and radar scanning results.

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5.3 Concrete Lintels

Concrete lintels do not appear to be structural members. Only 2 of 13 lintels evaluated were internally reinforced.

The primary structural member above window and door penetrations appears to be the shallow segmental arches at the exterior stone leaf. Concrete appears to be in place for 2 reasons: 1) provide support to the inner stone leaf, which has flat spans over openings; 2) provide a uniform closure to simplify window framing and installation.

Considering the severe cracking and deflections observed at many lintels and the fire damage to concrete materials, these lintels should not be considered as providing structural support. Lintels may remain in place if supported by external framing or otherwise retrofitted. Designing window frames with structural mullions to provide mid-span support is one option.

5.4 Retrofit Anchor Tension and Shear Capacity

Failure criteria for anchor tests are usually based on the methodology described in the International Existing Building Code (IEBC). The IEBC references Uniform Building Code Standard 21-7, Tests of Anchors in Unreinforced Masonry Walls, which stipulates that the tension test load be reported as the load that results in a relative movement of 1/8 inch between the tested anchor and the wall surface. As discussed above, a displacement-based failure criterion is not recommended in this case due to flexure of the pre-bent tension anchors and configuration of the test frame. Anchor capacity is instead based on the maximum applied load for each test. ASTM E488 calculates anchor capacity as the average of 5 anchor tests. In this case the average ultimate tension capacity is 7,500 lb. Applying a factor of safety of 4 to the average test values provides a design allowable tension load of 1,875 pounds. The coefficient of variation of test values is high, at 37%, due to the intentional widely varying installation conditions.

Only one anchor shear test was completed successfully and this result is not particularly useful for defining anchor shear capacity. At the one completed shear test an anchor capacity of 2,200 lb. was recorded. This installation was considered “poor” due to variable mortar fill conditions at the test location. Applying a factor of 4 to the ultimate strength provides a shear capacity of 550 lb. per anchor. This value should be considered a “lower bound” design value, and expected typical design values are likely to be 1.6 times this lower bound value, or in the range of 900 to 1000 lb. The low tested shear capacity is related more to poor conditions at the test anchor rather than low stone or mortar strength.

5.5 Recommended Mortar Formulation for Repointing and Rebuilding Mortar used for repointing joints, crack repair, and rebuilding should meet requirements of ASTM C270, Standard Specification for Mortar for Unit Masonry, for Type S mortar, with volumetric proportions as follows:

• 1 part portland cement

• 1/2 part Type S hydrated lime

• 3.5 to 4 parts sand

Sand should include a greater portion of coarse aggregate in the range of #4 to #16 sieve sizes to match existing mortar. See previous discussion in this report for appropriate mortar sand gradations.

The use of pigments may also be required to match the hardened mortar color. Pigments conforming to ASTM C979, Standard Specification for Pigments for Integrally Colored Concrete, are suitable for mortar, but should not exceed 5% by weight of binder content in the mortar. Trial mixtures will be required to arrive at a mix that matches the original mortar with respect to color and texture.

Pg. 34 9/6/2018

5.5 Recommended Masonry Strength Values

Stone was found to be competent and very hard, except for the outer fire-damaged layer. Mortar has a high cement content, is very hard, with little deterioration. Considering materials used on site, and results of in situ and laboratory tests conducted on other projects with similar materials, we recommend the following material strength values.

Stone masonry compressive strength, f’m

• Conservative = 3,000 psi

• Realistic value: 4,000 to 6,000 psi

Stone masonry bed joint shear strength, vm

• Conservative = 100 psi

• Realistic value: 200 to 350 psi

APPENDIX A

Photographs

Interior and Exterior Elevations

4019 4020

4021 4022

4023 4024

4025 4026

4027 4028

4029 4030

4031 4032

4035 4036

4037 4038

4039 4040

4045 4046

4204 4205

4206 4207

APPENDIX B

Field Notes

Atkinson-Noland & Associates Job No.:________________ Consulting Engineers By:____________________ www.ana-usa.com Date:___________________

ANA-DC

Text Box

MPS

ANA-DC

Text Box 7/10/18

ANA-DC

Text Box Sperry Chalet mschu Text Box Interior Condition

Mortar Color Concrete Color

Surface Distress: stone (depth)

Mortar distress: loose, detached

Footing distress:

Minor: no loose material, minimal repairs

Moderate: 1" to 2" delam, few/ no loose stones, repointing, minor stone removal

Severe:>2" delam, many loose stones, partial to total rebuild mschu Image mschu Image mschu Image mschu Image mschu Image mschu Image mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu

18-046

MPS

ANA-DC

Text Box 7/10/18

ANA-DC

Text Box Sperry Chalet mschu Pen mschu Text Box Exterior east wall

Stone

Head joints

Bed joints

Text Box Min Max Typ.

4*12 24*64 16*24

1/2 4 1.5

1/4 4 3/4

Image mschu Text Box Interior east wall

Stone

Head joints

Bed joints

Min Max Typ.

2*5 12*26 9*16

1/4 2 1

1/4 1.5 3/4

NPS GLAC Sperry Chalet

1/8" = 1'-0" 1st Floor Site Notes

2nd Floor Site Notes

Site Notes - North Wall Interior

1/8" = 1'-0" Site Notes - East Wall Interior mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Text Box Area not visible mschu Callout Collapsed mschu Text Box Area not visible mschu

Stone Condition Survey

Site Notes - West Wall Interior

1/8" = 1'-0" Site Notes - South Wall Interior mschu Text Box Stone Condition Survey Legend

Minor: minimal distress, < 1/4" stone loss

Moderate: mortar erosion, 1/4" to 1" stone loss

Severe: Mortar loss, > 1" stone loss mschu Image mschu Image mschu Arrow mschu Arrow mschu Arrow mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Text Box Area not visible mschu Pen mschu Pen mschu Rectangle mschu Rectangle mschu Rectangle mschu Rectangle mschu

Stone Condition Survey

MPS

ANA-DC

Text Box 7/10/18

ANA-DC

Text Box Sperry Chalet mschu Image mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen X mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen X mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen 25?

mschu Pen mschu Pen 20?

mschu Image mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen 8 8 mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen z mschu Pen mschu Pen mschu Pen z mschu Pen mschu Pen mschu Pen 8 12 mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen Y mschu Pen mschu Pen mschu Pen mschu Pen mschu Pen 10 7 mschu Pen mschu Pen 8 6 10 mschu Pen mschu Pen mschu Pen mschu Pen mschu Text Box Numbers represent individual stone thickness measured using 1500 MHz radar antenna. Dielectric calibrated at window sill stones where thickness could be directly measured.

mschu

Stone Thickness Survey

Site Notes - East Wall Exterior

1/8" = 1'-0" Site Notes - North Wall Exterior mschu Rectangle mschu Callout Radar stone thickness scans. See photo annotation.

Site Notes -South Wall Exterior

1/8" = 1'-0" Site Notes - West Wall Exterior mschu Arrow mschu Text Box mschu Text Box Radar scans Directory: Sperry Dielectric: 7.52 1500 MHz antenna Setup 06 MPS and Auralee mschu Arrow mschu Text Box mschu Callout Radar scan orientation, direction, and number, typ.

A

A

D

D

G

G

B

B

C

C

E

E

F

F

TITLE OF SHEETSUB SHEET NO.DESIGNED:

TECH REVIEW:

DATE:

DRAWING NO.

PMIS/PKG NO.

SHEET

OF6/

/2

1:

:4

P

M C

:\U se rs \J

S S

\D oc um en ts \1

_N P

S G

LA

C

S pe rr y_

C en tr al

_R

_J S

S .r vt

F1.01

JSS

GLACIER NATIONAL PARK

SPERRY CHALET RESTORATION

141725

246349

JSS

IRG

04/27/2018 ? 34

FIELD WORK

FOUNDATION PLAN

N

P S

G L A

C S p e rr y C h a le t

SCALE AF1.01

FOUNDATION PLAN1

SCALE OF FEET

1/4" = 1'-0"SCALE A

= buried or not visible

Stone Pier Condition Survey

S1.2_1_L2 (Wood RCP) - 109'-6" 109'-6"

S1.3_1_L3 (Wood RCP) - 127'-0" 127'-0"

S1.1_1_L1 (Wood) - 100'-0" 100'-0"

Ground (94'-0) 94'-0"

TO Wall (117'-0) 117'-6"

135 24

S1.2_1_L2 (Wood RCP) - 109'-6" 109'-6"

S1.3_1_L3 (Wood RCP) - 127'-0" 127'-0"

S1.1_1_L1 (Wood) - 100'-0" 100'-0"

Ground (94'-0) 94'-0"

TO Wall (117'-0) 117'-6"

1 3 52 4

TITLE OF SHEETSUB SHEET NO.DESIGNED:

TECH REVIEW:

DATE:

DRAWING NO.

PMIS/PKG NO.

SHEET

OF6/

/2

1:

:5

P

M C

:\U se rs \J

S S

\D oc um en ts \1

_N P

S G

LA

C

S pe rr y_

C en tr al

_R

_J S

S .r vt

F4.01

JSS

GLACIER NATIONAL PARK

SPERRY CHALET RESTORATION

141725

246349

JSS

IRG

04/27/2018 ? 34

FIELD WORK NORTH

& SOUTH WALL

ELEVATIONS

N

P S

G L A

C S p e rr y C h a le t

SCALE AF4.01

NORTH ELEVATION (GRID A)1

SCALE AF4.01

SOUTH ELEVATION (GRID G)2

SCALE OF FEET

1/4" = 1'-0"SCALE A

Marker at end of lintel 016, 017 Multiple vertical along lintel

13.75"

4"

Reinf.

7.5" sq.

4"

4"3

13"

018 lintel

Multiple Horizontal

Multiple Vertical

Radar stone thickness scans. See photo annotation.

Strong radar reflection. Void collar joint behind stone. 1" x 5" x 6"

Unreinforced

UnreinforcedReinforced Unreinforced

See sketch below

Concrete Lintel Elevation

Concrete Lintel Section

Reinforcement

Interior stone leaf

Exterior stone leaf at segmental arch above window opening

Stone extends into lintel, some locations

S1.1_1_L1 (Wood) - 100'-0" 100'-0"

Ground (94'-0) 94'-0"

TO Wall (117'-0) 117'-6"

A D GB C E F

TITLE OF SHEETSUB SHEET NO.DESIGNED:

TECH REVIEW:

DATE:

DRAWING NO.

PMIS/PKG NO.

SHEET

OF6/

/2

1:

:5

P

M C

:\U se rs \J

S S

\D oc um en ts \1

_N P

S G

LA

C

S pe rr y_

C en tr al

_R

_J S

S .r vt

F4.02

JSS

GLACIER NATIONAL PARK

SPERRY CHALET RESTORATION

141725

246349

JSS

IRG

04/27/2018 ? 34

FIELD WORK EAST

WALL ELEVATION

N

P S

G L A

C S p e rr y C h a le t

SCALE OF FEET

1/4" = 1'-0"SCALE A

SCALE AF4.02

EAST ELEVATION (GRID 1)1

019 lintel

022 023 Multiple

1" dlam at start of scan

2" core removed to 13.5" deep.

Solid stone to 12". Mortar solid above, 1/2" void at mortar filled collar joint.

Void bed joint 6" x 0.6" x 4" Similar occasional voids throughout, more common at head joints beyond 1" facing mortar.

Unreinforced Unreinforced

S1.1_1_L1 (Wood) - 100'-0" 100'-0"

Ground (94'-0) 94'-0"

TO Wall (117'-0) 117'-6"

ADG BCEF

TITLE OF SHEETSUB SHEET NO.DESIGNED:

TECH REVIEW:

DATE:

DRAWING NO.

PMIS/PKG NO.

SHEET

OF6/

/2

1:

:5

P

M C

:\U se rs \J

S S

\D oc um en ts \1

_N P

S G

LA

C

S pe rr y_

C en tr al

_R

_J S

S .r vt

F4.03

JSS

GLACIER NATIONAL PARK

SPERRY CHALET RESTORATION

141725

246349

JSS

IRG

04/27/2018 ? 34

FIELD WORK WEST

WALL ELEVATION

N

P S

G L A

C S p e rr y C h a le t

SCALE AF4.03

WEST ELEVATION (GRID 5)1

SCALE OF FEET

1/4" = 1'-0"SCALE A

010 011 012

009A Marker at end of lintel Multiple vertical along lintel

Lintel unreinforced

Multiple Vertical

Unreinforced

Reinforced

APPENDIX C

Radar Scans

2619 Spruce Street

Boulder, CO 80302

303.444.3620

32 Old Slip, 10th Floor

Project Name: By: Date:

Job No.: Test ID:

2619 Spruce Street

Boulder, CO 80302

303.444.3620

32 Old Slip, 10th Floor

2619 Spruce Street

Boulder, CO 80302

303.444.3620

32 Old Slip, 10th Floor

2619 Spruce Street

Boulder, CO 80302

303.444.3620

32 Old Slip, 10th Floor

2619 Spruce Street

Boulder, CO 80302

303.444.3620

32 Old Slip, 10th Floor

2619 Spruce Street

Boulder, CO 80302

303.444.3620

32 Old Slip, 10th Floor

2619 Spruce Street

Boulder, CO 80302

303.444.3620

32 Old Slip, 10th Floor

2619 Spruce Street

Boulder, CO 80302

303.444.3620

32 Old Slip, 10th Floor

2619 Spruce Street

Boulder, CO 80302

303.444.3620

32 Old Slip, 10th Floor

2619 Spruce Street

Boulder, CO 80302

303.444.3620

32 Old Slip, 10th Floor

APPENDIX D

Mortar Petrographic Analysis Report

� A Twining Company

Petrographic Investigation of Mortar Samples Extracted from the Sperry Chalet Located in Glacier National Park, Montana

Prepared for Mr. Michael Schuller, P.E.

Atkinson-Noland Associates, Inc.

Boulder, Colorado

Prepared by David Rothstein, Ph.D., P.G., FACI Report No. 187183.d 22 August 2018

3200 Carbon Place #104

Boulder, CO 80301

T: 303.938.0166 www.drpcinc.com http://www.drpcinc.com http://www.drpcinc.com

Sperry Chalet Hardened Masonry Mortar Analysis Page �i

EXECUTIVE SUMMARY

Two (2) samples of masonry mortar from the Sperry Chalet located in Glacier National Park, Montana are subjects of petrographic examination and chemical analysis per ASTM C1324 to characterize the composition and condition of the mortar represented by the samples and to evaluate the extent to which fire damage occurred. Sample Petro 1 is from an area near to where significant fire damage was observed while sample Petro 2 is from an area well away from significant fire damage.

The findings from this scope of work indicate that the mortars represented by both samples are sound and intact. Neither sample shows evidence of significant fire damage. The paste does not show discoloration typical of fire damage and neither sample shows evidence of cracking or microcracking typical of fire damage.

In Petro 1, which was reportedly closer to the severely fire-damaged section of the building than Petro 2, calcium hydroxide was observed in the paste as were some areas of elevated birefringence. Calcium hydroxide breaks down by dehydration at temperatures from 400-550ºC such that its presence places an upper limit on the temperatures attained by the mortars from exposure to fire in the areas that they represent. Although elevated birefringence and paste anisotropy was observed in Petro 1, it is more consistent with carbonation than fire damage.

Examination of the phenolphthalein-stained surface shows that no damage front, which would reduce pH from destruction of calcium hydroxide, affected the mortar. Intra-paste microcracks are present in Petro 1 but microcracking is not evident within the aggregate particles or at the interface between the paste and aggregate particles. As such, these microcracks are more likely due to shrinkage than fire damage. Collectively these observations indicate that in the areas they represent, the temperatures attained by the mortars did not exceed ~ 300ºC and were below the upper limit of 550ºC indicated by the breakdown of calcium hydroxide.

The mortar samples are consistent in terms of…