October 26, 2023 Project No 23067
Harlav Brar, PE
Utilities and On-Site Project Management
Capital Projects Department
Subject: Roessler Winery Structural Report
Pursuant to the request of Harlav Brar of the City of Fresno we have performed a field investigation and facilitated adobe brick testing on the structure in question for the above referenced project. This report summarizes our investig ation and our interpretation of the adobe brick testing.
Background
Brooks Ransom was retained to provide document searches , site investigation, and consult with the design team. On October 4 of 2023 and October 1 2 of 2023 Brooks Ransom performed site investigations on the Roessler Winery Building lo cated at 1902 N. Winery Ave, Fresno, CA 93703. The adobe brick testing is forthcoming as this i s a draft report to be reviewed by the City of Fresno.
General Building Discussion
The construction of the structure at the 1902 N. Wi nery is as follows: All four walls of the structure are unreinforced adobe brick (See Photo No. 1) . The walls terminate at an approximate elevation of 14’-10” above finish floor and t ransition to a 1x8 finish to the roof elevation. The floor framing consists of 8x8 beams suppo rted by 8x8 posts. In some instances, the beams appear to be 8x12 still supported by 8x8 posts. The floor framing consists of 2x12 joists at 16”o.c spacing (See Photo No. 3 and Exhibit No. 1). In some bays of the structure the floor framing switches to 32”o.c. spacing, but these a reas would need to be infilled to have a consistent floor framing system at 16”o.c. The floor sheathing itself appears to be 1x8 straight sheathing. The roof framing is field built trusses at 48 ”o.c. consisting of 2x6 top chords, 2x4 bottom chords and 1x8 web members (See Photo No. 2 and Exhibit No. 2). There is a post and beam system helping to support the roof trusses at both the north and south lines of the
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building. The roof appears to be unsheathed from a struct ural standpoint and has a corrugated metal roof running over the trusses. Foundati ons at this time are unknown, but are assumed to be built of rubble material similar to the ado be bricks used for the walls.
Severe cracks and deflection appear on the east and west ends of the building at the archways (See Photo No. 5) . Both archways are primarily adobe brick with some red brick infill. Based on the appearance of the archways it is our professional opinion to structurally reinforce the openings. Our recommendation is to des ign and install steel lintels that will only be visible from the interior of the building. The lint els can be installed with post-installed anchors into the adobe brick. Most likely the reinforc ing will need to be on both the lintel and the jambs, encompassing three sides of the opening. Alte rnative solutions would involve completely rebuilding the lintels with masonry or conc rete, but those solutions would involve the removal of the existing adobe bricks.
On the north and south sides of the building, settlem ent occurs at the foundation level (See Photo. No. 4) . No measures have been taken to mitigate the settleme nt. A soils engineer should be retained to perform a site investigation and pro vide a soils report to be utilized in the final design of the rehabilitation. The existing rubble foundations do not provide structural capacities to bridge the settlement issues. See the str uctural retrofit recommendations for more information on new foundations that will undermine the existing rubble foundations to stabilize the structure.
Based on site investigation and pending adobe brick testing, i t is our professional opinion that occupancy of this building shall require a full structur al retrofit. See the next section for retrofit recommendations and preservation of the historic nature of the structure. A structural engineer should be retained to provide further analysis .
Structural Retrofit Recommendations
The existing main structural system relies on the adobe brick to take both lateral and gravity loads down to the rubble foundation. Because of the brittl e nature of the adobe brick and the historical aspect of the building three different retro fit systems are recommended. All of the systems would occur on the inside of the building to pr eserve the adobe brick look from the outside of the structure.
The first system involves installing wood shearwalls a s the main lateral force resisting system.
Wood post and beams would be used to stabilize the gravity s ystem.
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The second system involves installing a shotcrete she arwall system as the main lateral force resisting system. Either wood or steel post and beams wo uld be used to stabilize the gravity system.
The third system involves installing a steel brace frame system as the main lateral force resisting system. Steel columns and beams would be used t o stabilize the gravity system. (See Exhibit No. 4)
Based on site investigation and conversations with the C ity of Fresno it is our professional opinion that a steel brace frame, steel columns, and steel beams would be the best system for this type of structure. Plywood floor sheathing will need to be installed to provide a structural diaphragm for the new lateral force resisting system. Rod-bracing can be utilized at the roof level to act as a structural diaphragm, but still allowing the existing sheet metal roof to be seen from the underside. New foundations w ould be recommended to stabilize the existing walls. Based on limited information, the exist ing foundations would need to be undermined by the new foundations.
The steel brace frame system is the only recommended s ystem that would allow the adobe brick to be seen from the inside. Because of the his torical nature of the building, this system would allow the ability to preserve the adobe brick from t he outside, but also admire the bricks from the inside. A structural engineer should b e retained to provide further analysis.
Structural Retrofit Probable Cost
The probable cost of retrofitting a historic structure such as the Roessler Winery building is extremely difficult to estimate. Until the final des ign is completed, the estimate may have a large range depending on the amount of work needed to make th e building compliant to the current code. A cost per square foot estimate is typic ally used in this scenario. Upon consulting estimators in the industry a cost of $200 pe r square foot shall be used for the structural retrofit. The building is approximately 5,000 square feet. Therefore, the probable cost of retrofit would be $1,000,000.
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Photograph No. 1
View from the street
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Photograph No. 2
Field built trusses
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Photograph No. 3
Floor framing
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Photograph No. 4
Adobe walls covered by
plaster
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Photograph No. 5
Adobe and brick archway
presenting cracks and
deflection
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Exhibit No. 1
Floor framing system
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Exhibit No. 2
Roof framing system
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Exhibit No. 3
Section through building
Exhibit No. 4
Wall section with proposed
structural system
Respectfully Submitted,
Scott Carter
Principal/CEO