VA PTRP Final Structural Assessment Report.pdf

Polytrauma Transitional Rehabilitation Program

Correct Foundation Problems for PTRP – Final Report for

South Texas Veterans Health Care System

November 11, 2019

IES Project No: 1182624

INTELLIGENT

ENGINEERING

SERVICES

10001 Reunion Place, Suite 200

San Antonio, Texas 78216

210.349.9098 Office

November 11, 2019

Mr. Rod Edwards

WestEast Design Group, LLC

200 E. Grayson Street, Suite 207

San Antonio, TX 78215 rode@westeastdesign.com

Re: AE Study, Correct Foundation Problems Polytrauma Transitional Rehabilitation Program

San Antonio, Texas

Dear Mr. Edwards:

The report included under this cover letter provides a description of the conditions observed in the existing building, and assessment of the structure based upon our observations. We initially observed conditions on

Tuesday, November 13th; and Wednesday, November 14, 2018. Follow-up site visits were made on February

20, 2019, May 15, 2019, and August 20, 2019 to monitor conditions and survey floor elevations in accordance with our Scope of Work of this project.

This report was prepared from a compilation of the following services provided by IES:

1. Review of the original design documentation.

2. Review of relevant submittals for the project that were made available for our review.

3. Observation of existing conditions at the site, including observation of existing construction during the initial geotechnical investigation.

4. Engineering analysis of the light gage steel framing.

5. Engineering check of the existing foundation design.

6. Interior floor elevation surveys.

7. Preparation of a site topographic survey.

8. Review of field reports prepared by the Structural Engineer of Record for the original project.

Please feel free to contact our office, at your convenience, should you have any questions or comments regarding the matters addressed or if additional information is required. We appreciate the opportunity to be of service.

Sincerely, David Gauthier, PE Agustin Tellez, Jr., PE

Senior Project Manager Partner

Intelligent Engineering Services, LLP Intelligent Engineering Services, LLP

Texas Registered Engineering Firm F-432

TABLE OF CONTENTS

COVER LETTER

EXECUTIVE SUMMARY

GENERAL STRUCTURAL DESCRIPTION

OBSERVATIONS OF EXISTING CONDITIONS

Exterior – General

Exterior – Test Pit

Interior – Slab Core

Interior – Floor Survey

Roof

Site

REVIEW OF THE ORIGINAL PROJECT GEOTECHNICAL REPORT

REVIEW OF CURRENT PROJECT GEOTECHNICAL REPORT

REVIEW OF EXISTING CONSTRUCTION DOCUMENTATION

Architectural Plans

Structural Plans

Civil Plans

REVIEW OF CONSTRUCTION MATERIALS AND TESTING REPORTS

REVIEW OF AVAILABLE SUBMITTALS

Light Gauge Cold Form Shop Drawings

REVIEW OF STRUCTURAL ENGINEER OF RECORD FIELD REPORTS

Report No. 091511-A, dated September 15, 2011

Memorandum Field Report, dated November 16, 2011

Report No. 010612-A, dated January 6, 2012

Report No. 030812-A, dated March 8, 2012

Report No. 040212-A, dated April 2, 2012

Report No. 060712-01, dated June 7, 2012

ENGINEERING ASSESSMENT OF EXISTING FOUNDATION DESIGN

Piers

Beams

Slabs

Detailing

CONCLUSIONS

RECOMMENDATIONS

LIMITS

ATTACHMENTS

1: Photographs

2: Interior Topo Plan for First and Second Floors

3: Civil Drainage Narrative and Site Grading Plans

4: inTEC Subsurface Exploration & Foundation Analysis (for reference only) – June 15, 2009

5: BEA Geotechnical Engineering Study (for reference only) – Updated May 17, 2019

AE Study, Correct Foundation Problems Polytrauma Transitional Rehabilitation Program

This report provides a description of the conditions observed in the existing building, and assessment of the structure based upon our observations. We initially observed conditions on Tuesday, November 13th; and

Wednesday, November 14, 2018.

For the purposes of this report, the front entry to the building into the Lobby area and with the drive-through

Porte Cochere is located on the plan south side of the facility. This wall actually faces toward the southeast, but for simplicity of understanding, plan directions instead of actual compass directions are used in this report.

Representative photographs (30 total) are included at the end of this report as Attachment 1, and are referenced in the following report narrative. Further, recommendations for the observed conditions are offered at the end of this report.

EXECUTIVE SUMMARY:

The detailed report should be considered in its entirety, but this brief summary is intended to give an overview of the major findings. The building construction was completed in 2012, and persistent cracking has developed in walls at both the interior and exterior of the building. We understand from users of the building, and from our observations, that the damage has been cosmetically repaired in the past, but continues to reappear. This prompted the present study in an effort to identify the cause for the observed distress, and to provide recommendations for repair of the facility.

Based upon the findings to date of the current investigation, it appears the primary cause for the observed damage is a construction method that allowed too much concrete, placed as a part of the primary concrete floor beams, to be in direct contact with the highly expansive clay soils at the site. A thin concrete shell over the sides of beam carton forms, intended to protect void spaces under the beams from filling with soil over time, extends well beyond the sides of the beam. This condition provides sufficient contact area for the expansive clay to exert enough pressure to lift the beams, and effectively negate the presence of the voids under the beams. This lifting has damaged the foundation beams and piers, and has resulted in the observed cracking of walls and finishes supported on the foundation beams.

A contributing cause for the damage is the lack of suitable drainage away from the building, which has allowed the soil moisture content to increase dramatically since the time of construction. The increase in moisture content has resulted in swelling of the highly expansive clay soils, which in turn has damaged the building foundation elements.

A review of available documentation relating to the light gauge framing used for the building superstructure indicates that the framing used for the building is adequate. However, we have concerns with the reported screw pop-out reported in interior gypsum board wall surfaces. The gypsum board provides lateral bracing for the building, and must remain in close contact with the metal stud wall framing to be effective. Screws that pop out are not able to keep the gypsum wall board in contact with the metal stud framing. The issue is addressed in a field report prepared by the structural Engineer of Record for the project, but there is no

Department of Veterans Affairs

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documentation related to any follow up that may, or may not have been, made with regard to recommendations made in his field report.

GENERAL STRUCTURAL DESCRIPTION:

The building is located at 4891 Gus Eckert Road in San Antonio, Texas. It is a two-story building originally constructed in 2011 – 2012. The structure consists of load bearing, light gauge steel framing members for walls and floors, and a light gauge steel truss framed roof system with a plywood roof deck.

The foundation is a reinforced concrete, structurally suspended slab and beam system supported on a deep drilled pier foundation. The concrete floor structure is indicated on the original structural drawings to be separated from expansive clay soils at the site by a 12” void created by the use of degradable, cardboard carton forms.

OBSERVATIONS OF EXISTING CONDITIONS:

Exterior - General:

Exterior observations revealed the presence of numerous cracks in the brick veneer of the building. Many of the cracks extended from the concrete foundation supporting the brick veneer up to window openings (see

Photos 1 and 2 for example). The cracks were primarily vertical in orientation which indicates the development of tension in the brick veneer. Cracks tend to develop where stress increases around discontinuities in a material, such as at window and door openings. These openings reduce the amount of brick available to resist stress build-up and therefore are common places for cracks to occur. The cracks we observed tended to be consistently wider at the top of the crack compared to the bottom of the crack near the foundation. This crack pattern is consistent with flexure in the plane of the brick veneer creating tension forces in the brick which increase moving from the bottom to the top of the veneer.

The ground surrounding the foundation appeared to be generally flat, with little to no discernible slope away from the foundation. More information regarding site grading is provided in the Civil narrative included as

Attachment 3 to this report.

Irrigation sprinkler heads had been installed immediately adjacent to the foundation around the perimeter of the building where concrete sidewalks did not exist (see Photos 3 & 7). In general, sealants used around windows, and in control joints in the brick veneer were in poor condition, or missing in areas (see Photo 4).

Sealants exhibited cracking due to movement related stresses. Given the age of the facility, none of the sealants should have been at or near the end of their normal service life (see Photo 5 for example). Some of the sealants had apparently been replaced, as they appeared to be newer, and sometimes had a slightly different color than the original sealants.

Downspouts from roof gutters, and discharge outlets for interior roof drains terminated immediately adjacent to the foundation (see Photos 6 through 8). Small concrete splash blocks were in place at these locations, but the lack of slope in the finish grade, and obstructions from planting and landscape concrete curbs apparently impede the flow of water away from the building foundation (see Photo 9).

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Exterior – Test Pit:

We observed the condition of the exterior concrete foundation beam, and the top of a drilled pier from a test pit excavated by Burge Engineering & Associates, Inc. (BEA) on the east side of the building (see Photo 10).

The purpose of the test pit was to observe for any distress to the foundation, and to check for the presence of a void under the concrete beam since there were no shop drawing/submittal available for review for the void forms used on the project.

Vertical cracks were visible in the exterior face of the concrete foundation beam which had been concealed from view below grade prior to excavation of the test pit (see Photo 11). The cracks in the beam were wider at the bottom of the beam in comparison to crack width at the top brick ledge. This crack pattern is typical for a flexural crack where tension has developed at the bottom of the beam. This is not a normal flexural condition over a support pier where tension would be expected at the top of the beam rather than the bottom.

We examined the bottom of the exterior concrete beam from the test pit, and confirmed that there was a clear void under the beam at this location (see Photo 12). The clear height of the void was measured to be 10 inches. Remnants of the cardboard void form system were visible, and the void boxes had entirely degraded as they are designed to do.

There was extensive concrete overpour below the formed beam side (see Photo 14). This concrete was measured to extend up to 8½ inches from the exterior face of the concrete beam, and is in direct contact with the expansive clay soil at the test pit location. See Photo 15, for a view of this condition.

The top of one of the existing drilled foundation piers was also observed from the test pit. The top of the pier was extensively cracked (see Photo 16) with crack width exceeding approximately 3/8 inch.

Interior – Slab Core:

In addition to the soil boring conducted at the building exterior by BEA, an interior soil boring was also made by core drilling through the existing concrete floor slab. The existing VCT flooring was removed, and existing steel reinforcement in the slab located and marked so that no reinforcing would be damaged when the slab was cored (see Photo 18 for setup). A four (4) inch diameter hole was cored through the existing concrete slab by BEA, and conditions were observed by IES.

A plastic vapor retarder was found at the bottom of the concrete slab. The material appeared to be at least 10 mil thick (see Photo 19). The core removed from the slab measured 11” in height, and was visibly cracked through the entire length of the core (see Photo 20). The concrete floor slab is scheduled to be 10” thick on the structural construction documents, so the thickness of the concrete was 1” greater at the core location.

The crack that was evident in the core removed from the slab could also be seen in the floor slab inside the cored hole (see Photo 21).

A continuous void which measured 10” deep was present below the slab at the core location. Void boxes used to form the void under the slab were completely degraded similar to the void forms observed under the exterior concrete beam. The soil at the bottom of the void was moist to the touch. A positive flow of humid, warm air was emanating from the cored hole indicating a positive air pressure under the floor slab. The source of this pressure could not be determined.

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After soil samples were collected by BEA, the cored hole and anchor holes for the drill where filled with concrete grout (see Photo 22).

Interior – Floor Survey:

Floor elevations were surveyed inside the building on November 13th and 14th, 2018 by IES. The elevations were taken using an electronic ZIPLEVEL® PRO-2000. Locations for elevations were selected that could be easily identified for planned future floor elevation surveys conducted as a part of this ongoing study. Both the first and second floors were surveyed, and floor elevations were adjusted where necessary to account for floor finish materials wherever a difference due to finish was measured.

Three (3) additional floor surveys were conducted on February 20, 2019, May 15, 2019, and August 21, 2019.

The floor elevation survey data was used to produce elevation contour plans for both the first and second floors, which are included as Attachment 2 to this report. Contours are indicated at 1/8” intervals on the attached plans with major contours indicated at ½” intervals. Review of the elevation data from the initial

November survey shows:

1. There is a maximum differential in floor elevation of 3⅛” at the First Floor.

a. The lowest portion of the floor slab is generally located near the southwest corner of the building, and extending just south of the main desk in the front Lobby. In both cases, the lowest points tend to occur near a drilled pier.

b. The highest point in the floor slab is located at the northeast corner of the building at Stair 2.

2. There is a maximum differential in floor elevation of 3½” at the Second Floor.

a. The lowest portion of the Second floor is generally located on the south side of the building at the southwest corner of the Gym/Work Out Area X201.

b. The highest point occurs along the middle of the east wall of the building.

3. Floor elevations change most rapidly along the east side of the building.

a. The floor slopes up 1⅞” in less than 12 feet between the first interior concrete floor beam along plan Grid 6 to the east exterior wall at the First Floor.

b. A similar upward slope occurs along the west side of the building, but the change in elevation is not as sharp because the first interior floor beam along Grid 2 is located over 21 feet away from the exterior wall, so the floor rises at a slower rate.

4. The east side of the building averages 1.68 inches higher than the west side of the building.

The initial survey revealed that the perimeter of the building is generally higher compared to interior floor areas. The east side of the building showed the highest elevation readings, with the floor getting progressively higher along the east wall moving toward the north.

Three subsequent floor elevation surveys conducted at 3-month intervals revealed that changes in floor elevations are ongoing, and have continued to occur during the monitoring period.

1. The February survey showed that floor elevations rose in areas up to 3/8” compared to the initial

November readings. The surface profile of the First and Second Floors remained relatively constant as evidenced by the similarity in the shape of the elevation contours developed from the survey data.

That is, the high spots remained high and the low spots in the floor remained low as is the case

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throughout the monitoring period. The elevation of the top of concrete slab generally increased between November and February.

2. The May survey showed that floor elevations generally remained the same, or were slightly lower by approximately 1/8” in most areas compared to the February elevations. Two exceptions to this occurred in the Southwest corner of the building where the floor elevation continued to increase from the February elevation by approximately 1/8”, and at the North side of the Kitchen/Dining area where the floor elevation increased approximately 1/4“ along the exterior walls compared to the February values.

3. The August survey showed that floor elevations continued to increase dramatically along the East side of the building where floor elevations were 3/4” to 7/8” higher than they were when first surveyed in November, and approximately 5/8” higher than they were in May. The abrupt increase in floor elevation in the three month interval between May in August suggests that soil moisture is migrating under the floor slab from the East side of the building. This trend in floor elevation increase extends under the interior portion of the floor slab to where the main desk is located in the Lobby. The remainder of the building showed either no change in elevation, to an increase of approximately 1/8” relative to the May readings.

Numerous cracks were observed in gypsum board walls. Most of the cracks were observed in corners where interior walls intersected with the exterior walls (see Photos 24 and 25). However, some cracks were observed in interior wall finishes, but not as often as at wall intersections and corners of window openings (see Photo

23) in the exterior walls. The floor slab was visibly unlevel under the door to First Floor room X113, where the uneven floor finish can be compared to the straight bottom of the pair of doors (see Photo 26).

Roof:

We also observed the roof mezzanine where several rooftop mechanical units are located (see Photo 27).

The roof area was generally dry at the time of our observation, and the area seemed to be provided with ample roof drains. We did not see any visible signs of distress in the roof membrane, or in the metal wall panels at the roof mezzanine.

A plywood covered deck is located inside the attic area for access to the roof (see Photo 29). The deck is accessed by a ladder located in Storage X211 with a lockable hatch installed in the plywood attic deck. From the vantage point of the attic deck, the light gauge steel truss roof framing was visible, but access into the general attic area was not otherwise available. The truss framing appeared to reflect the framing indicated on the submitted shop drawings for the roof framing that is discussed in a later section of this report in the limited area we were able to observe. We could not see the plywood roof deck attached to the top chords of the trusses as it was completely concealed from view by vinyl faced insulation.

Site:

A topographic survey of the building site was conducted for the purpose of developing a grading plan of existing conditions. The grading plan originally developed for the project was reviewed for conformance with normal Code requirements, and to identify areas in the original design that may be contributing to the observed distress to the building structure and finishes. Finally, a comparison of the original site grading to the current conditions is included as a part of our investigation. The topographic survey drawings and descriptive narrative for the conditions as noted above is included in Attachment 3 at the end of this report.

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REVIEW OF THE ORIGINAL PROJECT GEOTECHNICAL REPORT:

The original geotechnical investigation and report for the project, providing recommendations for the foundation design was completed on June 15, 2009 by Integrated Testing and Engineering Company of San

Antonio L.P. (inTEC). The report was prepared under the supervision and seal of E. A. “Paul” Palaniappan, Ph.D., P.E., Texas Board of Professional Engineer License No. 49065.

Seven (7) soil borings were completed in the preparation of this report to depths ranging between 7 feet for pavement recommendations to a maximum of 35 feet for foundation recommendations. The report identifies the soils at the site as “highly expansive in character” with potential vertical rise (PVR) on the order of 5¼ inches estimated from soil samples using test method TEX 124-E developed by the Texas Department of

Transportation. The original calculation of PVR assumed a surcharge load on the soil of approximately 1.0 pounds per square inch. This surcharge load tends to reduce the PVR, and typically would not be provided by a structurally suspended foundation that was used for this building. However, the site was filled and regraded

(see further discussion in the REVIEW OF EXISTING CONSTRUCTION DOCUMENTATION, Civil Plans) to provide a level area for the building, and the weight of fill to a depth of 1 to 1.5 feet would provide the assumed surcharge.

Foundation recommendations for the building included the use of either straight shaft piers, or drilled and under-reamed (belled) piers founded at a minimum depth of 27 feet below grade. For piers founded at the recommended minimum depth, an allowable end bearing capacity of 14,750 pounds per square foot was given. Further, piers embedded below the depth of 16 feet could also use a skin friction value of 875 pounds per square foot of pier shaft in contact with the soil for load carrying capacity. The original report states that piers founded at the 27-foot depth are expected to move on the order of ¾ inch due to the swelling characteristics of the underlying clays, or settlement characteristics of the soils.

Pier recommendations also included an equation for calculating the ultimate uplift force that the clay soil could exert on the piers for design purposes. The equation is given as Fu = 34d, where Fu = uplift force in kips (1 kip = 1,000 lbs), and d = diameter of the pier shaft in feet. In our experience, this formula will predict a much lower uplift force than what we generally see with expansive clay soils exhibiting the properties described in this report. See our REVIEW OF CURRENT PROJECT GEOTECHNICAL REPORT later in this report for a comparison of original and current uplift values.

The Boring Location Plan (Plate No. 1B in the Geotech Report), showing the location of the borings made for the project, show the location of the building on the site in a much different location compared to the final

Construction Documents. At some point between the time when the original geotechnical investigation was made in 2009, and the Contract Documents were issued for construction in 2011, the location of the building was moved closer to the street, and to the east side of the site. In fact, all four (4) borings initially planned to be within the building footprint, ended up outside the building footprint in the as-constructed condition.

Test results on soil samples taken during the site investigation indicate that the upper 5 to 7 feet of soil are very stiff, dark brown to dark tan clay with tested Plasticity Index (PI) values ranging from a low of 53 to a high of 66. PI is the difference between moisture contents of a soil sample where the soil can be formed into a prescribed shape by a standard test method. The Liquid Limit is the upper moisture content where the soil will

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no longer be able to hold a prescribed shape, and the Plastic Limit is the lower moisture content where the sample is too stiff to be formed to the prescribed shape. The higher the difference between the Plastic and

Liquid Limits (i.e. the higher the PI), the greater potential for a soil to undergo volumetric shrink and swell movements in response to changes in the moisture content.

Tests run on the moisture content of the samples taken indicate that the soil in all cases ranged between 3 to

5 percent below the Plastic Limit. This means the clay was below the moisture content where further shrinkage would not be expected to occur, and conversely, in a condition that would be conducive to maximum swell if the moisture content were to increase. The original soils report states with bold emphasis on Page 9, “If the moisture content is below or near plastic limit, the soils have high potential to swell.” This appears to be the case when the building foundation was constructed.

Soil below the upper layer is described as very stiff to hard tan clay to tan calcareous clay that transitions to marl. Where the PI was tested in this clay layer, it was generally lower than the PI of the upper soils on the site. Marl was not encountered in B-1 boring, but it is noted in the remaining deep borings. The boring log for

B-2 does not provide a depth for the marl, but simply indicates the tan clay transitions to marl. Boring logs for

B-3 indicated marl beginning at 15 feet, and B-4 indicates marl beginning at a depth of 14 feet below natural grade. The marl is a much harder, more stable material.

The Geotechnical Report provides several items that potentially influence the amount of movement an expansive soil may experience, including:

1. Soil moisture content is discussed related to the potential for soil movement. Our review of historical climate data for San Antonio, Texas during the month prior to, and the month during which, the floor slab and beams were placed indicate that rainfall experienced during these months was approximately one-half the normal average rainfall suggesting the ground was dry at the time concrete was placed.

Measured moisture content of the soil taken from samples recovered in 2009 show the in-situ expansive clay soils were dry. This indicates that conditions for soil swell were potentially maximized for the expansive clays if they were to experience an increase in moisture content after the foundation concrete was placed.

2. Lot drainage was discussed with the need to provide adequate slope of the soil away from the structure so that water is not allowed to collect and pond against or adjacent to the foundation. The importance of proper drainage away from the foundation is noted in several locations. Coupled with drainage, the prohibition against depositing water from downspouts and irrigation adjacent to the foundation is stressed.

3. Topography is discussed related to the potential for downhill movement associated with light foundations built on slopes in expansive soil areas. This does not appear to be of major concern for this building as the site was levelled for construction, and a concrete retaining wall provided that serves to limit the occurrence of this phenomenon.

4. Pre-Construction Vegetation discusses the influence of large amounts of vegetation on a site prior to construction that can dry soils out. This also does not seem to be a large contributing factor since the vegetation on the site appears to have been relatively sparse.

5. Post-construction vegetation discusses the influence of large trees adjacent to the foundation which can dry soils out, or the presence of flower beds and planting that require watering which can result in soil swelling. This also does not seem to be a major factor in the observed distress to the building as

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no large trees or heavy significant vegetation is close to the foundation.

REVIEW OF CURRENT PROJECT GEOTECHNICAL REPORT:

A limited geotechnical investigation was undertaken as a part of this study by Burge Engineering & Associates, Inc. (BEA), and a preliminary report was issued dated November 30, 2018 providing the results of that investigation. Additional borings were made and soil testing conducted during the monitoring period, and the report was updated on May 17, 2019 to incorporate the additional data. The report also includes recommendations for pier design based on the soil conditions that were observed to allow comparison with the original recommendations.

One test hole was drilled at the southeast corner of the foundation to a depth of 50 feet below finish grade

(see Photo 30). Since none of the original test holes (drilled in 2009) were located within the foundation footprint due to the apparent relocation of the building on the site, it was decided that it would be important to have a deep soil profile immediately adjacent to the foundation to help verify whether the recommendations offered in the original report were valid for conditions in the new building location. Also, the original borings from 2009 were only advanced to a maximum depth of 35 feet, and most of the piers scheduled on the structural construction documents extend below that depth. For example, the maximum depth of pier included in the foundation design is 45 feet below existing natural grade. The 50-foot depth of the current project investigation provides a soil profile for the maximum length of pier used on this project.

Another test hole was taken inside the building by core drilling through the concrete floor slab and sampling the soil under the building slab to a depth of 14 feet. This was the maximum depth that could be obtained with hand-held sampling equipment.

In addition to the two test holes, a test pit was excavated at the east side of the building foundation to uncover and expose the top of a building pier (located at the intersection of Grids C & 7 on the original Construction

Documents), and exterior beam. The test pit was excavated below the bottom of the building beam to allow observation of underside of the beam and the top of one of the building piers.

The report notes that conditions across this site can vary widely, and it is based on a single deep drilled test hole, but it is encouraging that the results of the sampling competed in 2009 and 2018 are consistent in many ways. The current project report indicates highly expansive native soils on the site, with an estimated PVR of

5½ inches considering no surcharge on the soil. This PVR was calculated using the same procedure, TEX

124-E, used in the original geotechnical report. The reported PVR value is in good agreement with the original estimate. The current project investigation identified a lower PVR at the interior sample due to the presence of a lower plasticity fill material used for the building pad during construction.

Of particular interest, the current project report indicates that the moisture content of the soil has increased since the 2009 geotechnical investigation. The moisture content of the upper, expansive clay soil (not fill installed during construction) was reported to be in the range of approximately 15-19% which is 3-5% below the Plastic Limit for the clay in the 2009 report. In the current project BEA report, the moisture content in the same soil strata is reported as 8% above the Plastic Limit at the exterior boring, and 10% above the Plastic

Limit at the interior boring. Clearly, the moisture content of the soil at the site has increased from the original test data, which would be expected to result in expansive swelling of the clay.

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Pier recommendations include a minimum 28 foot depth below finish grade for drilled straight-shaft piers to be embedded no less than 5 feet into Stratum III marl. The original soils report did not mention a minimum embedment into the marl, but the 27 foot minimum depth below grade in 2009 would have achieved the same or greater embedment since the initial report had been completed prior installation of site fill and regrading work for the building that was accomplished during construction of the facility. The BEA report includes a design bearing capacity of 22,500 psf based on total load, or 15,000 psf based on dead load plus long-term live load, whichever results in a larger bearing surface. In addition to end bearing, the report recommends that straight shaft piers may use a skin friction value of 600 psf for the portion of pier shafts in the clay soil (while neglecting the upper 6 feet), and 1,100 psf for the portion of the pier shaft in Stratum III marl. This produces reasonably comparable results to the single skin friction value of 875 psf given in the original inTEC report, since this report required that the upper 16 feet of the pier shaft be neglected in calculating pier uplift resistance.

One major difference between the original and current project reports is the equation provided for calculating the ultimate uplift force exerted on the piers by the soil. For the existing condition, which would be comparable to the 2009 report, the uplift force is to be computed by the equation Qu = 70 D, where Qu = uplift force in kips

(1 kip = 1,000 lbs), and D = diameter of the pier shaft in feet. This formula is much more typical with what we generally see for expansive clay soils exhibiting the properties of the expansive clay at the building site. Use of this formula gives an uplift force for pier design purposes that is (70/34 =) 2.06 times greater than the formula that was given for design of the piers. Pier uplift does not appear to be a controlling factor for the pier design considering the installed depth of the piers because the greater calculated uplift, using the BEA report, is resisted by an increased calculated uplift resistance using a Factor of Safety of 2.0. This increased resistance offsets the higher uplift values for each pier.

Additional borings were made at the site as a part of the established monitoring period for this report. These additional borings were made on February 20, 2019, and May 15, 2019 in the general location, and within a 6 foot diameter, of the initial S-1 boring made on November 13 and 14, 2018. The borings were advanced to a depth of 20 feet below existing grade for the purpose of monitoring soil moisture content over time.

The additional borings show that there was no free groundwater encountered in any of the borings during drilling operations. However, there were changes to the soil moisture content. The changes in moisture content varied with depth in each of the borings, and did not generally follow a consistent pattern. The report notes that rainfall rates in San Antonio, were higher than normal in 2018, and were on pace in May of 2019 when the final boring was made to be a wetter than normal year. However, soil samples showed that moisture content of the soil decreased in many samples, and increased in others. Soil moisture content percentages are compared in the report and the following recap shows the changes in moisture content (relative to the initial moisture content in November) at varying depths determined from samples taken in February 2019, and

May 2019, and indicates the soil response that would normally be expected:

Soil depth: Moisture Content (MC) Relative to Nov 2018: Soil Response to Change in MC:

0 to 1.5 feet 1% less in Feb, and 3% less in May Shrinkage

2.5 to 4 feet 6% less in Feb, and No Change in May Shrinkage, followed by Expansion

4.5 to 6 feet 1% less in Feb, and 1% less in May Shrinkage, followed by Stability

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6.5 to 8 feet 1% more in Feb, and 1% more in May Expansion, followed by Stability

8.5 to 10 feet 1% less in Feb, 2% less in May Shrinkage

13.5 to 18 feet 1% less in Feb, 1% less in May Shrinkage, followed by Stability

18.5 to 20 feet 3% more in Feb, 3% less in May Expansion, followed by Shrinkage

Data obtained from the additional borings made during the monitoring period was used to update the

Preliminary Geotechnical Report, and the updated Final Report of Geotechnical Engineering Study updated on May 17, 2019 is included for reference in Attachment 5 to this report. It is important to note that changes in soil moisture content of expansive clay soils generally occurs as a relatively slow process due to the fine grain structure of the soil. In other words, moisture migration occurs slowly over time in clay soils.

REVIEW OF EXISTING CONSTRUCTION DOCUMENTATION:

Architectural Plans:

Architectural drawings for the project, provided for our review, consisted of six (6) sheets, prepared by

WestEast Design Group of San Antonio, Texas. The drawings were noted to be Record Drawings, and were not sealed. The date on the reviewed record drawings was November 16, 2012.

The six sheets included:

• Plan drawings for the First Floor indicating dimensions, and a separate plan indicating plan notes, and section details on one sheet. These plans note the locations of the overflow scuppers from roof drains on the east and west sides of the foundation.

• Plan drawings for the Second Floor indicated the dimensions, and a separate plan indicating plan notes, and section details on one sheet.

• Plan drawings for the Roof indicating plan notes and section cuts, with typical roof details on one sheet. A typical splash block detail was provided on this sheet, which protects against ground erosion where roof drains and downspouts discharge next to the building foundation.

• Exterior elevations on one sheet. Each of the exterior elevations consistently show the location of downspouts that discharge at ground level adjacent to the foundation.

• Building sections and section details were indicated on one sheet.

• Wall sections were shown on one sheet. The wall sections show a continuous steel angle supporting brick masonry that is connected to the light gauge metal stud framing. The detail for the angle keyed on the wall sections was indicated to be on Sheet AS6.2, which was not included in the set of drawings provided for our review.

The set of Architectural drawings provided for review was not complete, but the drawings that would be useful to this study were likely provided.

Structural Plans:

The structural drawings for the project consist of eighteen (18) sheets, prepared by Cutler-Gallaway Services, Inc., TBPE Firm No. 609. The drawings were prepared under the supervision of the project Engineer of

Record, Thomas Galloway, PE, Texas License No. 35387, but were not sealed since they were project record documents.

Structural drawings appeared to be thorough, complete and generally well-coordinated with the Architectural

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drawings. We believe the drawings for the project show the design intent for structural aspects of the building, and they appear to conform to normal industry standards for structural construction documents.

The eighteen structural sheets provide the following information:

• Structural Notes and site details are indicated on one sheet.

• Foundation piers and reinforced concrete structure for the First floor are indicated on two (2) plan sheets, one (1) separate foundation detail sheet, and one (1) beam schedule for reinforcing (4 sheets total).

• Light gauge steel framing is indicated on five (5) plan sheets, and five (5) detail sheets (10 sheets total). Light gauge framing plan sheets show the First Floor wall framing, Second Floor joist framing, Second Floor wall framing, Roof mezzanine and low roof framing, and Roof framing. The detail sheets show typical light gauge framing details to set minimum design standards for the performance specified cold-form steel designer, overall building wall sections showing how the framing is arranged from foundation to roof, and two options for the roof framing. Sheet S501 shows a steel angle

L5x5x5/16 for support of limited amounts of brick veneer above windows, and above the Second Floor level. Connection of the L5x5 to the light gauge metal framing is indicated on this sheet.

• Structural steel framing for the south drive through are indicated on one sheet.

• Structural steel framing for the interior walkway along the south wall of the Second Floor is indicated on one sheet.

• Steel stairs are detailed on one sheet.

Civil Plans:

Civil drawings for the project provided for our review consist of eighteen (15) sheets, prepared by San Antonio

Design Group, Inc., TBPE Firm No. 5226. The drawings included the seal of the Civil Engineer of Record, R.

J. Akiona, PE, Texas License No. 50353.

The civil drawings indicate that the site was regraded and levelled for the construction of the building. The

First Floor elevation is indicated on the Civil plans to be 978.00 feet with the finish grade set approximately 1 foot lower than the floor elevation. Existing grade at the high southeast corner of the building was approximately 976.00 feet, and at the low northwest corner of the building it was approximately 969.50 feet.

This means about one foot of fill was required at the southeast corner of the building, and about 7.5 feet of fill at the northwest corner.

The natural slope of the site prior to construction of the facility and under the building footprint was downward from the southeast toward the northwest. The average natural slope of the site appears from the original grading plan to be an approximate 5.6% downward slope. After regrading the site as described above, the slope away from the building was reduced to approximately 2% at the south end of the east side of the building, and 3% at the north end of the east side of the building. A swale is indicated on the north portion of the west side of the building, but it did meet minimum slope requirements to remove water from adjacent to the foundation. Concrete landscape curbs and planting materials further inhibit drainage away from the foundation.

See the Civil narrative in Attachment 3 to this report for further discussion.

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REVIEW OF CONSTRUCTION MATERIALS AND TESTING REPORTS:

Construction phase material testing reports for the project were prepared by Raba-Kistner Consultants. We reviewed 133 individual test reports dealing with:

• Foundation pier drilling logs

• Proctor tests for subgrade and proposed fill materials

• Fill densities for building pad

• Fill densities for underground utilities

• Fill densities for site grading, roadways and parking areas

• Concrete reinforcing steel observations for building and site structures

• Concrete compressive strength test results for piers, building and site structures

• Masonry mortar and grout strength

• Asphaltic concrete mix design and densities

Our review of the test reports show that materials used on the project, in each of the areas listed above, met

Contract Document requirements. There were no low concrete strength test reports. Isolated cases where test results indicated non-conforming work, were re-tested or re-observed after correction, and found to conform to project requirements. Foundation pier logs indicate that all piers conformed to the project structural requirements, and were completed to the required depth, or slightly deeper.

REVIEW OF AVAILABLE SUBMITTALS:

Light Gauge Cold Form Shop Drawings:

There were three submittals made available for our review of the light gauge framing used on the project.

One of the submittals dealt solely with the light gauge steel truss roof framing. The drawings were prepared by Aegis Metal Framing, and sealed by James P. Looby, PE, Texas License No. 80377. The submittal did not include any detailed calculations for component members of the trusses, but the submittal did indicate the truss profiles, member sizes and connection requirements. The submittal had been reviewed and annotated by the structural Engineer of Record, Cutler-Galloway Services, Inc., and by the project Architect, WestEast

Design Group, LLC.

The other two submittals were for cold-formed metal stud and joist framing for the building. Both of the shop drawings were similar, and had the same hand-written review comments on them, but one included a modification to the layout of four interior walls to allow them to stack vertically between the First and Second

Floors. These shop drawings were prepared by Excel Engineering, Inc., and were sealed by Karl Scherzer, PE, Texas License No. 104271. Both of these submittals were reviewed and annotated by the structural

Engineer of Record, Cutler-Galloway Services, Inc., and by the project Architect, WestEast Design Group, LLC. There were no detailed engineering calculations for the metal stud design, but a hand-written review comment on the shop drawings pointed out that one of the light gauge floor beam reactions exceeded the capacity of a steel stud support post that was indicated on the plan. This suggests that detailed calculations had been submitted since the beam reaction would have likely come from the design report for the beam designed by the Contractor.

The General Notes for the light gauge shop drawings submittal indicated in Note 3, “All studs have been designed for uniform lateral loads and wall construction dead loads only. The weight of any masonry veneer

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is assumed to be supported independent of the light gauge framing.” This general note had been checked by some unidentified reviewer of the submittal. It does appear from our review of the Architectural and Structural drawings that a continuous L5x5x5/16 steel angle was screw attached to the metal studs for support of brick masonry. This load was evidently not included in the design of the light gauge metal stud wall framing, but the capacity of the studs to carry this limited brick veneer appears adequate for the imposed load from the brick.

REVIEW OF STRUCTURAL ENGINEER OF RECORD FIELD REPORTS:

We reviewed six field reports prepared by the project Engineer of Record, Thomas Galloway, PE, Texas

License No. 35387. The individual reports are described below.

Report No. 091511-A, dated September 15, 2011:

At the time of the visit documented by this report, no work was underway, and the foundation had been poured and preparations for wall framing were complete. The purpose of the site visit as stated in the report was to

“observe cracking reported in the foundation slab.” It appears from test reports for construction materials testing prepared by Raba Kistner Consultants, Inc. that the foundation slab was placed on July 27, 2011, so these cracks in the floor slab were observed less than two months after placement of the concrete.

The cracks that were observed are described in the report, and a conclusion offered that none of the cracks indicated foundation settlement or structural movements. All appeared to be related to shrinkage/curing of the concrete. The report also states that the crack aligned with the grade beam along Grid 4 is likely related to the fact that the lower portion of the grade beams were poured and cured prior to the slab pour. This tells us that an optional horizontal construction joint, indicated on the structural drawings, was used in the construction of the foundation. We will elaborate further on the significance of this joint in our analysis of the foundation design later in this report.

Memorandum Field Report, dated November 16, 2011:

The stated purpose of this Field Report was to review the progress of light gauge framing and structural steel erection. The work described as currently in progress in the report included First Floor light gauge wall installation, and Second Floor metal decking. In general, the work is reported to appear in conformance with the structural contract documents, and the light gauge supplier’s shop drawings, with a few deficiencies identified including inadequate header clips at second floor openings, missing joist web stiffeners in a few locations, the need for a stud splice under a window header on the west wall, shear wall strap bracing required at a few shear wall locations, shear wall tie down installation was not complete, but were being installed, and some walls were not complete at the time of the visit. There were no photographs included with this report.

Report No. 010612-A, dated January 6, 2012:

The stated purpose of this Field Report was to review the Second Floor shear wall assemblies and installation.

Work described as currently in progress in the report included second floor walls being installed and roof trusses being fabricated. There were five items provided in the report describing either on-going work, or deficiencies in the work. Items to verify included a note concerning adequate fasteners at all tiedowns, and the need for alternate strapping where shear walls were interrupted. Action required is listed for the Contractor to propose alternate shear wall strapping where duct installation had interrupted the strapping in some of the shear walls. The noted incomplete items were followed up on by Mr. Gallaway in a later field report dated April

2, 2012 described below. There were no photographs included with this report.

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Report No. 030812-A, dated March 8, 2012:

The stated purpose of this report was to observe modifications made to first floor shear walls. The work described as currently in progress in the report included soundboard being installed on interior walls in preparation for in-wall inspection. The report indicates that modifications to shear walls were in general compliance with January 30, 2012 calculations and details prepared by Excel Engineering. However, these calculations and details were not made available for review by IES. Two deficiencies were noted in this report including a flat strap that had not been welded at the top in Shear Wall 1E11, and one post in Shear Wall 1E4 was missing reinforcing studs.