VA AUDIE MURPHY ROOF REPORT Signed.pdf

AUDIE L MURPHY MEMORIAL VETERAN’S HOSPITAL

Department of Veterans Affairs Roof Loading Analysis

Report

LFE Project No.: 03-404-00

Prepared for:

WestEast Design Group 200 E Grayson Unit 207 San Antonio, TX 78215

Prepared by:

Lundy & Franke Engineering, Inc.

549 Heimer Rd.

San Antonio, Texas 78232

210.979.7900 tel Texas Board of Professional Engineer Firm Registration #3388

Shawn J. Franke, P.E.

Principal

Jose D. Hernandez, EIT Engineer

Report

LFE Project No.: 03-404-00

Prepared for:

WestEast Design Group 200 E Grayson Unit 207 San Antonio, TX 78215

Prepared by:

Lundy & Franke Engineering, Inc.

549 Heimer Rd.

San Antonio, Texas 78232

210.979.7900 tel Texas Board of Professional Engineer Firm Registration #3388 sfranke

SJF TX

sfranke Typewritten Text 08-29-2023

Roof Loading Analysis

At the request of WestEast Design Group, Lundy & Franke Engineering, Inc. (LFE) performed an investigation of the low roof trusses at Audie L Murphy Memorial Veteran’s Hospital. This report summarizes the findings of our assessment, conclusions, and conceptual repair recommendations.

BACKGROUND AND DESCRIPTION

The Audie L Murphy Memorial Veteran’s Hospital was built in 1970 and is a multi-level, multi-building campus. The structures that populate the campus are a combination of cast-in-place concrete and structural steel. The roof structure being analyzed for this portion of the project and report is composed of structural steel trusses at approximately 11’-0” on centers throughout all portions of the low roof structure. The trusses support a 3” – 20-gauge metal roof with insulated concrete deck. The total depth of deck and concrete is 6”. The deck supports approximately 6” of built-up roof system covered by a gravel layer. Existing drawings indicate that there may be 7” of tapered insulated concrete for roof drainage sloped to roof “zero” levels.

This information has not been independently verified and will require field verification upon removal of existing roof materials.

DOCUMENT REVIEW

Design and construction related documents reviewed by LFE that are relevant to the items presented in this report include, but may not be limited to, the following:

Architectural and structural drawings titled “760 Bed M.S. & N. Psychiatric Hospital” for the Veteran’s

Administration dated 08-03-1970.

Structural Calculations for Solar Roof Rack by MBL Energy dated April 28, 2014.

San Antonio VA Hospital Grid-Tied Solar Photovoltaic System drawings by Overtaking Engineer

H2DC PLLC 12/01/2022.

Limited Structural Peer Review VA Hospital Rooftop Solar Panels dated November 17, 2022 by

Terracon Consultants, Inc. for HICAPS.

OBSERVATIONS, DISCUSSION, AND OPINIONS

The following sections summarize LFE’s evaluation of the roof trusses for added loading imposed by the partially installed photvoltaic panel farm on the low roof structure.

Roof Structure Investigation Scope The scope of LFE’s investigation includes the load capacity of the existing roof trusses in relation to the existing roof structure and applied loadings and the structure’s ability to support the additional loading of a solar panel farm over the footprint of the low roof.

ALM Memorial Veterans Hospital Dept. of Veteran’s Affairs

Document Review The available drawings and documents provided to LFE contain the designed structure for the roof areas under evaluation. The drawings also contained the designed truss layouts associated with the areas of evaluation. Information includes member size, span, location, and allowable loading on structural plans.

The documents provided also include the information regarding the loading of the solar/photovoltaic panel structure including peer review of the design calculations.

Observations and Comments

Multiple site visits were made to observe complete and incomplete installation progress. During one site visit on June 13, 2023 an investigatory selective demolition was conducted by Tremco Roofing, with representatives from LFE and WestEast present. A built up roof system, consisting of gravel, asphaltic material, lead barrier and insulation was removed down to the insulated concrete deck. The composition of all materials was approximately 4”-6” thick. Built Up Roof systems can weigh anywhere between 5 to 15 pounds per square foot. A full material analysis by a testing company can determine the exact weight of all materials. Our analysis utilizes conservative values where true values are not known and records are not available for our use.

Evaluation of Trusses

Lundy & Franke Engineering, Inc. utilized SAP2000 – 25 to evaluate the truss configurations based on the existing drawings listed in the “Document Review” section of this report. The drawings provided are not marked “As-Built” and do not reflect with 100% accuracy that which was built. The drawings listed design loads utilized for roof loading. The design engineer designed a superimposed roof live load of 20psf and a dead load of 16psf. The concrete on roof deck is expected to be insulating concrete that typically weighs 20-40 pounds per cubic foot. The original design drawings indicate that the roof was originally topped with 0 to 7 inches of insulated concrete above the 6-inch concrete and metal deck roof. Our exploratory selective demolition indicates that the roof system was either replaced or not built as indicated in low roof structural drawing sections. Our selective demolition was limited to one roof location of approximately 1 square foot and is not indicative of what may be uncovered during reroofing construction.

Within the SAP200-25 program, the trusses were modeled by member size and framing spacing as noted within the structural plans and truss design sheets. They were then subjected to computer modeled loading analysis applying the roof loading as prescribed by the original structural engineer. The Structural engineer of record allowed for 20 psf Live Load and 16 psf Dead Load superimposed on the roof. Our preliminary analysis indicated that the existing Built-up Roofing system, noted in our “Observations and Comments,” section would require, approximately, the full allowable superimposed dead load capacity.

The wind uplift forces, and downward forces, as supplied by the design calculation packages were also applied to the computer modeled trusses. All forces at connections were applied to multiple iterations of placement locations due to lack of attachment documentation by the original panel designer.

Recommendations

LFE’s computer modeled evaluation of the existing roof trusses based on all available information and best engineering practices determined that the roof, as currently constructed and finished, cannot support the additional loading from the rooftop solar/photovoltaic panel farm. The roof structure can support the rooftop solar/photovoltaic panel farm if the following criteria are met:

Roof Loading Analysis

• Verification of existing roof composition across the entirety of the low roof structure. Verifying that the built-up roof material currently in place and the 6” insulated concrete and metal roof deck assembly are the only material currently on the roof.

• Verification of the existing built-up roof material unit weight (pounds/ square foot) for full analysis of reduction of weight on the existing roof.

• Replacement of existing built-up roof system with alternative roofing to reduce dead load on existing roof structure.

• Verification of proper attachment of existing solar panel support posts during reroofing construction.

CONCLUSIONS

It is Lundy & Franke Engineering’s opinion that the roof, as currently composed, cannot support the addition of a photovoltaic/solar panel farm on top of the low roof as an additional dead load. However, the removal of the built-up asphaltic/gravel roof system noted in this report and observed by this office can increase the available capacity of the superimposed roof dead load once verification of material weight has been completed and applied to an additional analysis. The allowable superimposed dead load capacity may increase by approximately 5 to 15 psf, dependent on the roof material weight analysis.

An alternative method to evaluating the roof capacity is provided in International Building Code 2021 1607.14.4.1 and the 2018 International Solar Energy Provisions CS507.1.1.1 which states the following:

Roof structures that support photovoltaic panel systems shall be designed to resist each of the following conditions:

1. Applicable uniform and concentrated roof loads with the photovoltaic panel system dead loads.

Exception: Roof live loads need not be applied to the area covered by photovoltaic panels where the clear space between the panels and the roof surface is 24 inches (610 mm) or less.

2. Applicable uniform and concentrated roof loads without the photovoltaic panel system present.

The panels and support structure are within the qualifying criteria listed in the International Building Code excerpt above. Any previously installed solar/photovoltaic panels already installed that do not meet these criteria should be remediated.

It is our opinion that based on the IBC 2021 provisions in 1607.14.4.1, the roof is capable of supporting the solar/photovoltaic panels without removal of the existing roofing materials. However, we highly recommend removal and replacement of the existing roofing materials for repair and upkeep of roofing with the solar panels intended to be installed. Furthermore, removal of the current existing built up roof material may place the roof structure and already installed solar/photovoltaic panel assemblies out of compliance with the IBC 2021 1607.14.4.1 qualifications with the installation of a new, lower profile, lighter weight roofing system.

CLOSING

The findings from this investigation were based on visual field observations, exploratory openings, and limited analysis. The conclusions and recommendations are based on the observed conditions at the subject property at the time of the investigation and a review of documents available for our review at the time of this report. LFE reserves the right to modify our findings should additional information become available or if we perform additional on-site observations and/or testing. Our recommendations and/or opinions do not represent a design or specification for repairs. Additional investigation may be required as part of a comprehensive remediation design.

LIMITATIONS

This report has been prepared to assist WestEast Design Group in understanding the nature and type of distress investigated in this study and determine a future course of action. Lundy & Franke Engineering, Inc. assessed specific issues relevant to the distress observed at the Audie L. Murphy Memorial Veteran’s Hospital.

Lundy & Franke Engineering, Inc. has no direct knowledge of, and offers no warranty regarding the condition of concealed construction or subsurface conditions beyond what was revealed in our review.

Any comments regarding concealed construction or subsurface conditions are our professional opinion, based on engineering experience and judgment, and derived in accordance with current standards of care and professional practice.

Various other non-structural, cosmetic, and structural damage unrelated to this assessment may have been observed throughout the structure, some of which are discussed in general in this report. However, a detailed inventory of all cosmetic, nonstructural, and structural damage was beyond the scope of our assessment. Comments in this report are not intended to be comprehensive but are representative of observed conditions. In this study, we did not include review of concealed conditions or a check for conformance to the applicable codes.

Repair recommendations discussed herein are conceptual and will require additional engineering design for implementation. Our professional services have been performed with a level of skill and expertise usual and customary for a professional engaged in this type of work and is consistent with generally accepted engineering practice. We appreciate this opportunity to be of service. Please call if you have any questions, or if we can be of future assistance.

We have made every effort to reasonably present the various areas of concern identified during our site visits. If there are perceived omissions or misstatements in this report regarding the observations made, we ask that they be brought to our attention as soon as possible so that we can fully address them in a timely manner.

This report has been prepared on behalf of and for the exclusive use of WestEast Design Group and its clients. This report and the findings contained herein shall not, in whole or in part, be disseminated or conveyed to any other party or used or relied upon by any other party, in whole or in part, without prior written consent.