ATTACHMENT_5_GWMP_214371-BellReanalysisReport-Final-030818.PDF

27 February 2018

Ms. Anne Weber Mills + Schnoering Architects 200 Forrestal Road Suite 3A Princeton, NJ 08540

Project 172157.03 – Reanalysis of NPS Netherlands Carillon Structure, Arlington, VA

Dear Ms. Weber:

Enclosed is our revised report summarizing our reanalysis findings, conclusions, and recommendations regarding proposed rehabilitation of the above-named project.

Please note, an adjustment to the bell weights is visible in Table 1 and discussed in Section 3.0.

The analysis results did not change. The information is in the report is revised to include weight of the new framing supporting bells 1, 2, 2a, and 3. While included in our calculations, the framing and its impact on the weight of the structure was not visibly apparent in the previous report. It is important to note this does not change the structural recommendations or previous analysis results. It merely changes the way in which the information is presented in the report.

Sincerely yours, Matthew J. Daw, P.E., LEED AP Michael D. Zajac Laura M. Burgess Senior Principal Senior Staff II – Structures Senior Staff I – Structures VA License No. 0402041026 I:\DC\Projects\2017\171132A NPS Netherland Carillon Rehabilitation\3 Correspondence\1 Design Phases\4 K&H issued corresp\Renalysis Report\001MJDaw-L.172157.03.eac.docx

Structural

Analysis Report

NPS - Netherlands Carillon

Arlington, VA

16 February 2018

Revised: 27 February 2018

SGH Project 172157.03

Boston

Chicago

Houston

New York

San Francisco

Southern California

Washington, DC www.sgh.com

Design, Investigate, and Rehabilitate

PREPARED FOR:

Mills + Schnoering Architects

200 Forrestal Road, Suite 3A

Princeton, NJ 08540

PREPARED BY:

Simpson Gumpertz & Heger Inc.

1828 L Street NW, Suite 950

Washington, DC 20036

Tel: 202.239.4199

Fax: 202.239.4198

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Table of Contents

Letter of Transmittal

CONTENTS

1. INTRODUCTION 1

1.1 Summary 2

2. DESCRIPTION OF EXISTING STRUCTURE 3

2.1 Foundations 3

2.2 Superstructure 3

2.3 Lateral Force-Resisting System (LFRS) 4

3. CALCULATIONS AND ANALYSIS 5

3.1 Code Prescribed Loads 5

3.2 Assumptions 6

3.3 Task 1: Basis of Design Reanalysis 8

3.4 Modified Design Reanalysis 9

3.5 Qualifications / Clarifications 10

4. SUMMARY AND RECOMMENDATIONS 12

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1. INTRODUCTION

As part of a team collaboration between the National Park Service (NPS) and the Royal

Netherlands Embassy, a design team has been assembled to compile bridging documents to facilitate rehabilitation and upgrade of the Netherlands Carillon Structure (Carillon) to address significant structural deterioration and restore public access to the tower. NPS desires the addition of three new bells to raise the memorial to a Grand Carillon status. The new bells weigh approximately 7,040 lbs, 100 lbs, and 100 lbs for a combined additional load of approximately

7,240 lbs. An initial analysis was conducted the summer of 2017 to determine the existing structure’s capacity and its ability to support loads of new bells.

Following the initial analysis, Royal Eijsbouts Foundry (Foundry) provided additional information regarding equipment and bell support components which were either altered or removed as part of the 1994 rehabilitation campaign. The Foundry also provided information regarding equipment and bell support components which would be altered or removed as a result of the proposed rehabilitation and upgrade. The overall weight of the bells and their components post the 1994 rehabilitation campaign is estimated to be approximately 79,000 lbs. The overall weight of the bells and their components following the proposed rehabilitation and upgrade of the Carillon to a

Grand Carillon status, is estimated to be approximately 73,500 lbs. The proposed rehabilitation and upgrade of the Carillon to a Grand Carillon status results in a weight reduction of approximately 5,500 lbs.

At the request of the Mills + Schnoering Architects (M+Sa) on behalf of the NPS, Simpson

Gumpertz & Heger Inc. (SGH) was retained to perform the following structural tasks as a modification to the original scope of work:

Reanalyze the existing tower structure utilizing 1994 and currently planned rehabilitation campaigns. The analysis will not include the weights of the proposed new bells and their respective components and framing.

• Basis of Design shall utilize:

1. Code prescribed loading as modified by the Structural Engineer of Record for future use and public access.

• Basis of Design shall establish:

1. Need and extent of potential reinforcing required to facilitate rehabilitation of structure such that the structure may be reopened for public access. New bell weights are not included in the basis of design for Task 1.

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Reanalyze the existing tower structure utilizing revised bell configuration and weight of new bells as proposed by Royal Eijsbouts Foundry in their document dated 20 December 2017

(Doc 4331-014_Rev). This analysis will also include the loads identified in Task 1 as well as the weight alterations associated with the proposed rehabilitation efforts.

• Modified Design shall utilize:

• Code prescribed loading as modified by the Structural Engineer of Record for future use and public access.

• Modified Design shall establish:

2. Need and extent of potential reinforcement required to facilitate rehabilitation and upgrade the Netherlands Carillon. New bell weights are included in the modified design.

3. If a weight limit exists to avoid potential reinforcement while adding a portion of the anticipated new bell loads, SGH will provide the recommended limit.

1.1 Summary

For Tasks 1 and 2, reanalysis results indicate demand on the bottom 16 ft of the steel interior columns extending up from grade (i.e., eight total columns) is above capacity for one or more of the code modified loading combinations. The columns require strengthening to accommodate the demands and satisfy code required loading combinations.

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2. DESCRIPTION OF EXISTING STRUCTURE

The Netherlands Carillon structure, located in the National Park Service George Washington

Memorial Parkway in Arlington, Virginia is an iconic structure memorializing a friendship between the Netherlands and the United States following World War II. The structure presents sweeping views of the Potomac River, the National Mall and Arlington Cemetery.

Constructed in 1960, the Netherlands Carillon is a 127-ft open steel structure.

2.1 Foundations

The entire Carillon superstructure bears upon a reinforced concrete mat slab footing below the plaza pavement. The mat slab is 40 ft - 0 in. square and 2 ft - 0 in. thick, and bears approximately

6 ft - 6 in. below the finished plaza surface. Reinforced concrete piers extend up from the top of mat slab footing to support the vertical columns of the above-grade Carillon superstructure.

2.2 Superstructure

The Carillon superstructure consists of metalized built-up box vertical columns and horizontal beams fabricated from an assembly of steel angles and intermediate steel stiffener plates.

Additional stiffener plates are positioned within the box sections where horizontal box beam connections are located. Built-up box beams and columns are clad in metalized steel plates fastened to the angle structural components with bolts and rubber isolation hardware. Structural connections between built-up box beam and column sections consist of both bolted and welded connections.

Observation Decks 1 and 2 consist of steel checkered plate supported by steel angle supports. Between Observation Decks 1 and 2, a service level is present, framed with open steel mesh flooring supported by steel angle framework hung from the existing built-up steel box beams with a series of bent steel plate sections. It is believed that the mesh flooring is not original to the structure.

The bells at the Bell Support Level (below Observation Deck 2) are supported by built-up box beams, steel angles, channels, and wide flange beams. The upper bells located below the

Soundboard Roof hang from conventional wide flange steel beams which in turn frame into the built-up box column sections of the superstructure.

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Pedestrian access to Observation Deck 1 is provided by a central steel-framed stair assembly consisting of checkered plate landings supported by steel angles, which frame to four vertical steel wide flange columns. Each stair assembly flight consists of open risers with checkered plate treads supported by steel plate stringers.

A spiral steel stair with open risers provides access from the Observation Deck 1 to Observation

Deck 2 / Clavier Room. A steel ladder provides access to the base of the Upper Bell Level /

Clavier Room Roof.

2.3 Lateral Force-Resisting System (LFRS)

The lateral force-resisting system of the Carillon consists of moment frames in both the north/south and east/west direction.

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3. CALCULATIONS AND ANALYSIS

3.1 Code Prescribed Loads

For Task 1 and Task to analyzes, the structure was reviewed in accordance with the International

Building Code 2015 edition (IBC 2015), the International Existing Building Code 2015 edition

(IEBC 2015) and the American Society of Civil Engineers Minimum Design Loads for Buildings and Other Structures 2010 edition (ASCE 7-10). Code applied loads and design assumptions utilized in the analysis are summarized below for Tasks 1 and 2.

• Lateral Loads

• Wind Load

1. Exposure Category = C

2. Basic Wind Speed VULT = 115 mph

3. Risk Category = I

• Seismic Design Criteria

1. Site Class C

2. Ss = 0.119

3. S1 = 0.051

4. Fa = 1.2

5. Fv = 1.7

6. Seismic Risk Category = II

7. Seismic Design Category = A

• Floor Level Loads

• Observation Deck – 1

1. Dead Load: 5 psf + self-weight

2. Live Load: 100 psf

• Observation Deck – 1.1. Bell Chamber

1. Dead Load: 5 psf + self-weight

2. Live Load: 40 psf

• Bell Support Level

3. Dead Load: Bell weights. Note: No floor is present at this level. The level is composed of built-up box beams to support existing Bell #2 thru existing Bell #8.

• Observation Deck – 2

1. Dead Load: 5 psf + self-weight

2. Dead Load (Clavier Room): 10 psf + self-weight

3. Live Load: 100 psf

• Bell Tower Roof

1. Dead Load: 10 psf + self-weight

2. Live Load: 20 psf

3. Snow Load: 30 psf

SGH compared the results of the basis of design analysis with that of the modified design structure with proposed new bell loads. The stress level and demand-capacity ratio of the structural elements was reviewed with respect to the International Existing Building Code 2015 edition

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(IEBC 2015), Chapter 11. Bell weights are depicted in Table 1. Bell weights include their components such as frames, beams, clappers, and headstocks.

3.2 Assumptions

ASCE 7-10 provides recommended factored load combinations for design of structures. However, in these instances, the code specified factored load combinations do not reflect realistic loading conditions for the Carillon structure. For example, it is unlikely the structure will be loaded with full live load and partial snow load during a high wind event. As such, through the experience and judgment of our engineers, SGH has modified the load cases as indicated below for analysis of the Carillon structure.

1. 1.4 Dead

2. 1.4 Dead + 1.6 Live

3. 1.2 Dead + 1.6 Snow + 0.25 Live*

4. 1.2 Dead + 1.6 Snow + 0.5 Wind

5. 1.2 Dead + 1.0 Wind + 0.25 Live* + 0.5 Snow

6. 1.2 Dead + 1.0 Earthquake + 1.0 Live + 0 Snow*

7. 0.9 Dead + 1.0 Wind

8. 0.9 Dead + 1.0 Earthquake

* Indicates Modified Load Factor

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Table 1 – Bell Weights

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3.3 Task 1: Basis of Design Reanalysis

Task 1 analysis utilized the following items:

• Code prescribed loads as noted in Section 3.1,

• Modified factored load combinations noted in Section 3.2, and

• Revised bell weights noted in Table 1, column 4 “Task 1 Bell Weights (#)”.

• 1994 bell campaign weight revisions,

• Proposed rehabilitation campaign weight revisions,

• Excludes weight of new bells.

It is SGH’s understanding that the 1994 revisions included minor framing reconfigurations of the bell support structure to create a stationary bell configuration as opposed to the original dynamic configuration for select bells. SGH understands that the proposed upcoming bell rehabilitation campaign will include removal of the existing bells for tuning purposes followed by reinstallation utilizing updated bell components and structural connections to the exiting built-up box beam structure. The rehabilitation work includes revisions to the bell transmission system.

As noted in Table 1, the weight of the existing bells and their components post 1994 revisions was estimated to be approximately 79,000 lbs. Task 1 reduces the overall super imposed dead load of the bells and their components to 71,000 lbs, a reduction of approximately 8,000 lbs.

Analysis of the existing structure indicates demand on the bottom 16 ft of the steel interior columns extending up from grade (i.e., eight columns total) is above capacity for one or more of the modified loading combinations noted above. Figure 1 depicts the eight columns in plan.

Reinforcing the eight columns pictured in Figures 1 and 2 is recommended. Reinforcement may include the addition of full height stiffener angles (L2x2x5/16) at the interior of each of the existing column angles. Please reference Figure 3 as illustrated in the structural schematic design documents for suggested existing column reinforcement.

The reinforcement concept has been provided to facilitate order of magnitude preliminary cost estimating exercises.

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Figure 1 – Tower Plan Figure 2 – Tower East/West Elevation

Figure 3 – Section – Column 2 (C2) Strengthening

3.4 Modified Design Reanalysis

Task 2 analysis utilized the following items:

• Code-prescribed loads as noted in Section 3.1,

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• Modified factored load combinations noted in Section 3.2, and

• Revised bell weights noted in Table 1, Column 5 “Task 2 Bell Weights (#)”.

• 1994 bell campaign weight revisions,

• Proposed rehabilitation campaign weight revisions,

• Includes weight of new bells 2a, 51, and 52, approximately 8,500 lbs.

The addition of new Bell 2a requires resupport of existing Bells 1, 2, and 3. As such, the existing support members shall be removed and replaced with a new beam and four new ‘A’ frame supports. The new framing will be provided and detailed by the Foundry.

As noted in Table 1, the weight of the existing bells and their components post 1994 revisions was estimated to be approximately 79,000 lbs. Task 2 reduces the overall super imposed dead load of the bells and their components to 73,500 lbs, a reduction of approximately 5,500 lbs.

Overall, the weight of the bells and their components increases by approximately 2,500 lbs between Task 1 and Task 2. Additional reinforcing beyond that noted in Task 1 is not required for the weight increase between Task 1 and Task 2.

Analysis of the existing structure indicates demand on the bottom 16 ft of the steel interior columns extending up from grade (i.e., eight columns total) is above capacity for one or more of the modified loading combinations noted above. Figure 1 depicts the eight columns in plan.

Reinforcing the eight columns pictured in Figures 1 and 2 is recommended. Reinforcement may include the addition of full height stiffener angles (L2x2x5/16) at the interior of each of the existing column angles. Please reference Figure 3 as illustrated in the structural schematic design documents for suggested existing column reinforcement.

The reinforcement concept has been provided to facilitate order of magnitude preliminary cost estimating exercises.

3.5 Qualifications / Clarifications

It is important to note the following:

• The condition of the existing structural elements is largely obscured from view by existing cladding. Where visible, the structure was observed for signs of distress. Probes were conducted at select locations to assess the condition of the hidden structural elements (angles and plates). However, the probes represent a small percentage of the overall structure. The condition of the existing structure may vary significantly throughout.

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• A detailed review of the structure is recommended to be conducted by the Structural Engineer of Record (SER) for the future Tower Rehabilitation and New Bell Installation work at the time all cladding panels are removed. Removal of cladding during an early design phase for observations can reduce the potential of encountering unforeseen conditions during construction.

• A detailed structural analysis shall be the responsibility of the SER for the future Tower Rehabilitation and New Bell Installation work. The SER is responsible for final selection of code-appropriate load combinations and may implement modified load combinations differing from SGH’s assumptions noted above. The SER shall obtain approval from the governing building official and NPS for load combinations that vary from the prescribed ASCE 7-10 load combinations.

• The existing structure has remained in stable condition since construction in 1960. Proposed rehabilitation and new bell weight loads decrease the weight on the structure as compared to the current state of the existing, which reflects the 1994 modifications.

• Despite the items noted above, it is important to understand the structure to date may not have realized full loading conditions represented by modified load combinations.

• It is recommended that the SER shall utilize their independent analysis results and field observations of the exposed structural members to determine the final extent of potential reinforcing and/or replacement of existing structural members required.

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4. SUMMARY AND RECOMMENDATIONS

To assist with bridging and schematic design documents, SGH performed a reanalysis of the existing structure with proposed revised loading configuration and weights as provided by the

Foundry.

Reanalysis results indicate demand on the bottom 16 ft of the steel interior columns extending up from grade (i.e., eight total columns) is above capacity for one or more of the code modified loading combinations. The columns require strengthening to accommodate the demands and satisfy code required loading combinations.

The recommendations and comments herein are based on SGH’s visual observations during our site assessment and the professional judgment and experience of SGH engineers. This report represents the extent of SGH’s review.

I:\DC\Projects\2017\171132A NPS Netherland Carillon Rehabilitation\3 Correspondence\1 Design Phases\4 K&H issued corresp\Renalysis Report\2018-02-27 SGH 172157.03-ADDS Netherlands Carillon 214371 MOD 0001 Reanalysis Report

REVISED.docx