ESBD_366445_1720045536029_Exhibit H Structural Assessment Report.pdf

01.09.24

Mr. Brit Barr

Architect

Historic Sites Division

Texas Historical Commission

P.O. Box 12276

Austin, Texas 78711-2276

Re: Magoffin Home State Historic Site Visitor Center - Structural Assessment

1117 Magoffin Avenue, El Paso, Texas

JQ Project No. 4230206

Dear Mr. Barr:

JQ Infrastructure, LLC (JQ) performed a limited structural review of the exterior brick masonry walls of the

Magoffin Home State Historic Site Visitor Center, 1117 Magoffin Ave., El Paso, Texas on October 4, 2023.

The purpose of the review was to assess the structural condition of the building for the purpose of providing recommendations for repair.

Our findings are as follows:

Building Description

The building is a two-story structure constructed with wood framed roof and floors, interior loadbearing wood framed walls, exterior unreinforced brick masonry walls, and shallow stone footing foundations.

The brick masonry walls are two-wythes in thickness and were constructed without header courses.

Previous renovations of the building were completed in 2014 and 2022. The 2022 renovation incorporated structural repairs and modifications of the brick masonry walls including:

• Repointing of mortar joints and cracks within the walls

• Installation of regularly spaced helical pins to tie the two brick wythes together.

• Installation of helical bars to mechanically connect the brick masonry on each side of existing cracks.

• Installation of regularly spaced connections between the second floor and roof framing to the top of the loadbearing brick masonry walls.

• Installation of regularly spaced connections between the first floor framing and the loadbearing brick masonry walls.

Magoffin Home State Historic Site Visitor Center - Structural Assessment, 1117 Magoffin Avenue, El Paso, Texas

JQ Project No. 4230206

Observations

Observations were made of the building interior and exterior. In addition, observations of the interior of the brick masonry walls in the distressed areas using an endoscope inserted into the wall at cracks. My observations include:

• The majority of the exterior face of the brick masonry façade is in good condition with no observed cracking or displacements. Cracks which were repaired during the 2022 renovation have not redeveloped.

• Significant cracking with associated outward wall bowing has occurred around the bay window on the west side of the building. The cracking at the upper north corner of the bay window is most pronounced with a width of approximately 3/8 inch. The outward bow of the wall is approximately 3 inches. Temporary wood framed lateral bracing has been installed. Lateral movement of the wall appears to be caused by settlement of the foundation. Refer photographs

1 to 6.

• A joint has opened between the brick wall of the main building and the brick wall at the front porch at the southwest corner of the building. The brick walls are constructed independent of each other with no common coursing of the brick. Refer photograph 7.

• The south brick wall at the southeast corner of the building has a crack that extends the full height of the wall above and below the window. Refer photographs 8 and 9.

• Connections between the first floor framing and the brick masonry walls which could be reviewed in the area of the bowed west wall are intact. Evidence of the previous helical pin installation was observed at one location. Refer photograph 10.

• Cracks were not observed in the interior face of the stone foundation wall forming the crawl space. Refer photograph 11.

• Connections between the second floor and roof framing to the top of the masonry walls which could be observed in the area of the bowed wall are intact.

• Cracking of interior wall finishes was observed in the same regions as the exterior wall cracking and movement.

• Some settlement of the floor immediately adjacent to the exterior wall in the women’s restroom is present.

• The exterior brick wythe has separated from the interior brick wythe and bowed outward. The cavity formed by this separation has allowed the original mortar in the space to break apart and fall lower in the wall. Helical pins observed appear to have pulled out of the mortar joints in which they were installed. Refer photographs 12 to 14.

Movement Monitoring

Crack monitors were applied to the masonry wall by THC staff at three crack locations at the west bay window. These locations and the recorded movements are:

• Below the window – The crack has remained stable with recorded increase in crack width of

0.1mm (0.004 inch) between October 17 and December 7, 2023.

• Mid-height at chimney - The crack has remained stable with recorded reduction in crack width of

0.5mm (0.020 inch) between October 17 and December 7, 2023.

• Top of wall - The crack has experienced some movement with recorded increase in crack width of 1.6mm (0.063 inch) between October 17 and December 7, 2023.

Magoffin Home State Historic Site Visitor Center - Structural Assessment, 1117 Magoffin Avenue, El Paso, Texas

JQ Project No. 4230206

Discussion

Per the geotechnical investigation completed by CQC Testing and Engineering, LLC for the 2022 renovations, the soils on this site are expansive and thus can experience heave or settlement due to variations in the moisture content. Settlement is most pronounced during drought conditions as experienced in this region. If foundation movement occurs, brittle materials such as unreinforced brick masonry and plaster wall finishes as found in the building will experience cracking. This cracking is normal but can be excessive and cause structural distress if the movement is significant. In areas of differential foundation movement as apparent at the bay window, the soil related movement can cause rotation of the supported wall resulting in bowing as observed.

Based on site observations including imagery of the wall interior gained by the endoscope, the two brick wythes have separated with the outer wythe bowing outward from the building. The inner wythe appears to still be vertical with minimal, if any, lateral bowing or displacement. The supplemental helical pins installed during the prior repairs appear to have pulled out of the mortar in one or both of the brick wythes at the locations observed.

Testing conducted during the 2022 renovation determined that the supplemental helical pins could be installed “dry” (without the use of chemical adhesives) in the existing mortar joints and still attain the required strength to tie the brick wythes together to resist anticipated loading stipulated by the building code. The tensile strength of helical pins installed in this manner is governed primarily by the integrity and bond strength of the mortar. Therefore, if the mortar in the area of observed cracking is weaker than found in other areas of the building, the helical pins may not have attained the desired strength. Further, movement of the supporting foundations impart additional unanticipated loading on the walls which could exceed the tensile capacity of the helical pins and result in cracking and associated distress.

The ability of unreinforced brick masonry walls of a given height to resist vertical and lateral loading is primarily dependent on the strength of the mortar and the thickness of the wall. The helical pins placed during the prior repairs were installed in the wall to better connect the two brick wythes so that the wythes would continue to act as one 8 inch thick wall instead of two separate 4 inch thick walls. The loss of this connection as evidenced by the bowing outer brick wythe has substantially reduced the structural capacity of the wall. For example, the reduction in flexural capacity to resist lateral loading is estimated to be approximately 75%.

Recommendations

Based on the existing conditions, we recommend the following:

• Vertical shoring should be installed within the building to support the second floor and roof to grade within the crawl space. This shoring can be limited to the areas of observed cracking in the exterior brick masonry wall at the west bay window. Shoring can consist of a wood framed wall which is tightly fitted to the underside of the first and second floors and bears on a 2x12 sill plate in the crawl space. It is understood that the installation of this shoring may impact the use of the restrooms.

• The cracked and displaced areas of exterior brick can be removed after shoring is in place. It is believed that the inner brick wythe can remain and care must be taken during removal of the exterior wythe so as not to damage the inner wythe. The condition of the inner brick wythe must

Magoffin Home State Historic Site Visitor Center - Structural Assessment, 1117 Magoffin Avenue, El Paso, Texas

JQ Project No. 4230206 be confirmed after removal of the exterior wythe. Removed brick can be salvaged if desired, but use of replacement brick in reconstructing the wall may be appropriate given the final paint finish.

The existing wall should continue to be monitored until the distressed outer brick wythe is removed.

• Alternatively, both brick wythes can be removed and replaced. However, this will have significant impacts on interior finishes and building systems in the area of wall replacement.

• If the inner brick wythe is maintained, the replacement exterior brick wythe should be mechanically anchored to the inner wythe and the space between the wythes should be fully filled with mortar. Pull tests of the mechanical anchors should be completed prior to construction of the new brick wall.

• The existing foundation at the bay window should be stabilized. This may include underpinning or placement of a root/moisture barrier wall in front of the existing footing foundation.

• Ties between the wall and the second floor/roof and first floor framing should be reinstalled if damaged by the wall demolition and replacement.

• After structural repairs are complete, interior finishes can be repaired.

Disclaimer

The opinions and comments provided in this report are based upon field observations as part of our scope of services. JQ has used reasonable professional efforts to determine the visually apparent defects in the building structure. However, as field observations were conducted on a structure in which the majority of the structural elements are concealed, JQ cannot be responsible for failing to ascertain deficiencies which were not visible due to the existing conditions in the building. No warranty expressed or implied, regarding the condition of the building structure is intended. In addition, no representation as to the expected useful life of the building structure or other components identified in this report is made.

If you have any questions, or if we can be of further assistance, please contact us.

Sincerely yours, JQ Infrastructure, LLC

Texas Registered Engineering Firm: 7986

Stephen H. Lucy, PE 1/8/2024

Partner

Magoffin Home State Historic Site Visitor Center - Structural Assessment, 1117 Magoffin Avenue, El Paso, Texas

Photograph 1 - Cracking and temporary bracing at west bay window.

Photograph 2 - Cracking and temporary bracing at west bay window.

Magoffin Home State Historic Site Visitor Center - Structural Assessment, 1117 Magoffin Avenue, El Paso, Texas

Photograph 3 - Cracking and temporary bracing at west bay window.

Photograph 4 – Cracking and temporary bracing at west bay window.

Magoffin Home State Historic Site Visitor Center - Structural Assessment, 1117 Magoffin Avenue, El Paso, Texas

Photograph 5 - Cracking and temporary bracing at west bay window.

Photograph 6 – Bracing configuration at west bay windows.

Magoffin Home State Historic Site Visitor Center - Structural Assessment, 1117 Magoffin Avenue, El Paso, Texas

Photograph 7 – Separation in brick masonry at west side of front porch.

Photograph 8 - New crack in brick masonry at east side of front porch.

Magoffin Home State Historic Site Visitor Center - Structural Assessment, 1117 Magoffin Avenue, El Paso, Texas

Photograph 9 – New crack in brick masonry at east side of front porch.

Photograph 10 – Typical first floor tie to wall. Note helical pin projecting through interior face of wall.

Magoffin Home State Historic Site Visitor Center - Structural Assessment, 1117 Magoffin Avenue, El Paso, Texas

Photograph 11 – Typical stone construction at base of wall.

Magoffin Home State Historic Site Visitor Center - Structural Assessment, 1117 Magoffin Avenue, El Paso, Texas

Photograph 12 - Open cavity between brick wythes at west bay windows.

Magoffin Home State Historic Site Visitor Center - Structural Assessment, 1117 Magoffin Avenue, El Paso, Texas

Photograph 13 - Open cavity between brick wythes at west bay windows.

Magoffin Home State Historic Site Visitor Center - Structural Assessment, 1117 Magoffin Avenue, El Paso, Texas

Photograph 14 – Open cavity between brick wythes at west bay windows.