B12_-_Miscellaneous_Correspondence_(MISC)_-_Attachment_2_-_Inspection_and_Recommendations.pdf

U.S. FISH AND WILDLIFE SERVICE OFFICE AND

MAINTENANCE BUILDING

Culebra, PR

Inspection and Recommendations

STRUCTURAL REPORT

OF OBSERVATIONS

SUBMITTED TO: Gabriel Rodriguez

THIS DOCUMENT HAS 11 SHEETS

(DATED May 24, 2023)

D. Leon Structural Engineering Urb Veredas #14 Camino de los Flamboyanes, Gurabo PR 00778

TEL. 787-313-6996 Email dleonstruct@yahoo.com

PURPOSE:

The purpose of this report is to provide observations from the site visit and suggest recommendations for any deficiencies observed in the structure. The site visual inspection and evaluation request arises as a result of a significant horizontal crack observed on one of the interior partition walls.

INTRODUCTION:

The building inspected is a steel gabled frame structure with CMU partitions and exterior sheathing. It is a single-story building with a mezzanine that occurs in 2 of the 5 bays. The building’s footprint is 100’-3” x 40’-3” with an average height of 16’-8”. It is currently being used as a work shop, storage facility and office space for the USFWS Culebra’s administration.

The construction documents used as part of this evaluation are dated March 1991. Accordingly, the building would have been designed under the 1987 Puerto Rico Building Code: Reglamento de Edificacion #7. This code considers Puerto Rico under one seismic zone and incorporates the requirement of ductility detailing.

This report will present the observed damage and any deficiencies in the structure and provide an alternate remediation for these.

OBSERVATIONS:

The building was inspected fist from the exterior and then the interior. The observations are as follow:

• There is some corrosion observed on the Southwest corner of the roof (see Photo 1). It appears to be superficial but should be repaired to avoid larger repairs in the future.

• The North face of the building was observed with diagonal hairline cracks on the cmu wall (see Photo 2, 3, 4). These cracks appear to be the result settlement of the slab on grade. They may be repaired according to detail “HAIRLINE CRACK REPAIR DETAIL” in the Appendix.

• East and South face of the building have similar cracks (Photo 5 and 6). These may be repaired with “HAIRLINE CRACK REPAIR DETAIL” in the Appendix.

• The partition wall along axis 5 appears to have settled at the center causing the wall to crack at various locations (see Photos 7 and 8). These cracks appear to be repaired.

This wall extends up to the mezzanine level. The construction documents detail proper anchorage of the top of the wall to the diaphragm system at mezzanine level.

• The slab on grade along axis 3 has settled significantly, causing the cmu wall to crack (see Photo 9, 10, 11 and 13). The wall is unable to handle the tension from the downward movement of the slab on grade and forms a horizontal crack. This crack is close to 1/8 inch wide and it can be seen through. The original construction documents specify this wall as follows:

o “8” CMU WALLS W/TRUSS TYPE HORIZ. WALL REINF. @16” O/C VERT.

EXTEND WALLS TIGHT TO STL. FRAME ABOVE & @ ENDS AND SEAL

(TYPICAL)”

There is no indication of a mechanical anchors of the wall for out of plane forces. This anchor system is required to transfer the out of plane forces to the roof’s diaphragm or lateral framing.

• The primary structural element of the building is the steel framing. There was no observed damage to the steel framing. There are no available construction documents to observe in detail the structural system. However, there does appear to be lateral design considerations. In the short direction the gable frames function as moment frames. In the long direction there was an observed cross bracing between axis 2 and 3 (see Photo 12).

CONCLUSION:

The integrity of building’s structure was found in acceptable condition. No damage or deterioration was observed withing the structure. The observed settlement causing the damage is attributed to the slab on grade movement. The steel columns are supported on isolated square footings at a depth of 4’-3”. The footings are usually designed according to a Geotechnical Engineer’s recommendations which include depth and soil bearing capacity. Given no sign of settlement in the area of the columns and observable settlement towards the center of the building it may be concluded the foundation system for the structure is proper.

The settlement of the slab on grade could be attributed any number of reasons. This settlement does not affect the integrity of the structure. However, the wall in question along axis 3 does have considerable damage and needs to be addressed. This wall is not part of the structural system but does create a safety issue. The lack of mechanical anchors to the diaphragm and the significant horizontal crack leaves the wall with no out of plane resistance.

This wall shall be repaired. Considering the damage and the above-mentioned risks, it shall be partially demolished. In particular the area affected by the crack. The wall is to be replaced with a new wall reinforced as indicated in the repair details in the Appendix. Mechanical anchors of the wall to the roof structure are included in these details. The new partition wall will be finished with proper consideration of possible lateral loading therefore providing a safe environment.

DISCLAIMER:

This report is based on visual inspection of the structure and the original construction documents.

The conclusions presented in this report are constrained the date indicated and to the building evaluated and shall not be considered in part or in full in the case another such event occurs which could affect the structure.

Contractor shall provide information of findings during construction process. This may be in the form of photographs. The purpose is to correlate findings to details in the original construction drawings.

Daniel J. Leon

PE# 15320-PR

APPENDIX:

Appendix A: Photos from first visit on April 18, 2023

PHOTO 1 PHOTO 2

PHOTO 3 PHOTO 4

PHOTO 5 PHOTO 6

PHOTO 7 PHOTO 8

PHOTO 9 PHOTO 10

PHOTO 11 PHOTO 12

PHOTO 13 PHOTO 14

REPAIR DETAILS

GENERAL NOTES:

1. Existing mezzanine shall be properly shored prior to commencing work.

2. Roof’s steel beam shall be properly measured to define steel angle as indicated on “NEW BEAM DETAIL”

3. Concrete shall have a 28 day strength of 3,000 psi

4. All reinforcement bars shall conform to ASTM A-615 (Fy=60 ksi)

5. Any difference in the existing structure to what is assumed shall be informed to the Engineer.

6. The new steel angles welded to the existing roof steel beam shall apply to the complete wall, not just the new portion.

WALL ALONG AXIS 3 REPAIR DETAILS