Structural Report by WSP.pdf

USCG BASE ELIZABETH CITY

STRUCTURAL INSPECTION AND EVALUATION OF

RESCUE SWIMMERS POOL ROOM IN BUILDING #3

DRAFT

USCG BASE ELIZABETH CITY

STRUCTURAL INSPECTION AND

EVALUATION OF

RESCUE SWIMMING POOL ROOM IN

BUILDING #3

UNITED STATES COAST GUARD

STRUCTURAL INSPECTION AND EVALUATION REPORT

USCG BASE ELIZABETH CITY, NC

USCG CONTRACT 70Z05018DBERBAM04, TASK ORDER 70Z08321FPCR05500

PROJECT NO.: 31800149.001

DATE: NOVEMBER 2, 2021

WSP USA SOLUTIONS, INC.

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November 02, 2021

Evan Amorgianos, P.E.

Civil Engineer, Design Team Alpha U.S. Coast Guard Civil Engineering Unit, Cleveland

Subject: STRUCTURAL INSPECTION AND EVALUATION REPORT

USCG BASE ELIZABETH CITY, NC

USCG CONTRACT 70Z05018DBERBAM04,

TASK ORDER 70Z08321FPCR05500

Dear Mr. Amorgianos:

As requested by your task order referenced above, please find our Final report attached for your review.

Yours sincerely, Robert Maslyn, RA Project Manager

Encl.

cc:

WSP ref.: 31800149.001

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L I S T O F P R E P A R E R S , A G E N C I E S , A N D P E R S O N S C O N T A C T E D

CLIENT

Contracting Officer James Dinda

Contracting Specialist Valerie J. Varga, CEU Cleveland

Project Manager Evan Amorgianos, P.E., CEU Cleveland

WSP

Contract Manager Guy Mallozzi

Project Manager Robert Maslyn, RA

Supv. Structural Engineer Weiying (Shirley) Chiang, PE

Structural Engineer Matthew Wilde, PE

SUBCONSULTANTS

Cost Estimating Dennis Teschlog – ProDims

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S I G N A T U R E S

PREPARED BY

Matthew Wilde, PE

Structural Engineer

REVIEWED BY

Weiying Chiang, PE

Supervising Structural Engineer

This report was prepared by WSP USA Solutions Inc. for the account of USCG Cleveland, in accordance with the professional services agreement. The disclosure of any information contained in this report is the sole responsibility of the intended recipient. The material in it reflects our best judgement in light of the information available to it at the time of preparation. Any use which a third party makes of this report, or any reliance on or decisions to be made based on it, are the responsibility of such third parties. The JV and WSP accept no responsibility for damages, if any, suffered by any third party as a result of decisions made or actions based on this report. This limitations statement is considered part of this report.

The original of the technology-based document sent herewith has been authenticated and will be retained by WSP for a minimum of ten years. The electronic file transmitted is now out of our control and its integrity can no longer be ensured, no guarantee may be given with regards to any modifications made to this document.

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L I S T O F A C R O N Y M S

A/E Architectural and Engineering MPH Miles Per Hour

BAJV BergerABAM Joint Venture OC On Center (center to center spacing)

CG Coast Guard PCI Present Concrete Institute

CL Centerline PSF Pounds Per Square Feet

CMU Concrete Masonry Unit PSI Pounds Per Square Inch

DT Double Tee (Precast Concrete) ROM Rough Order of Magnitude

FP Fire Protection RS Rescue Swimmer

GWB Gypsum Wall Board SOG Slab on Grade

KSI Thousand Pounds Per Square Inch USCG United States Coast Guard

MEP Mechanical, Electrical, Plumbing WSP WSP USA Inc.

WSP

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TABLE OF

CONTENTS

1 EXECUTIVE SUMMARY

2 STRUCTURAL ASSESSMENT

2.1 EXISTING CONDITIONS

2.2 REPORT OF FINDINGS

2.2.1 VISUAL SURVEY

2.2.2 ANALYSIS OF PRECAST DOUBLE TEE DESIGN

2.2.3 ANALYSIS OF BUILDING DESIGN

2.2.4 OTHER ISSUES

2.2.5 SUMMARY OF THE INVESTIGATION

3 PROPOSED RESTORATION

3.1 IMMEDIATE ACTIONS RECOMMENDED

3.2 PROPOSED SCHEME OF RESTORATION

3.2.1 DEMOLITION

3.2.2 NEW ROOF STRUCTURE

3.2.3 RESTORATION

3.3 COST ESTIMATE

REFERENCES

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APPENDICES

A. SITE INVESTIGATION PHOTOGRAPHS

B. REFERENCE DRAWINGS

C. COST ESTIMATE

D. STRUCTURAL CALCULATIONS

USCG Elizabeth City Investigation Report Nov. 02, 2021

RS Pool Room in Building 3 Final

1 EXECUTIVE SUMMARY

This document presents the record of a structural investigation into the cause of falling concrete and cracking of the precast double tee roof over the RS Pool, from the perspectives of both building physical condition, and its adequacy of engineering design and construction quality. This document also provides a possible solution to correct structural deficiency while preserving and maintaining occupancy of the majority of the Building 3 facility.

The subject of this investigation is in the US Coast Guard Base, Building 3 Rescue Swimmer Training

Facility in Elizabeth City, North Carolina. The scope of work is limited to the Rescue Swimmers (RS) Pool portion of the building which is used as training site for Coast Guard personnel. The building was built around 2012, according to as-built drawings. The basic structure of the pool hall is 110 feet wide, 196 feet long, 25 feet high from pool deck to bottom of the double tees (DTs). The DTs span the full width of this space, bearing on concrete corbels integrated with the sandwiched precast concrete wall. This pool hall is structurally connected to the rest of the

Building 3. The RS Pool is attached to a wave generating chamber that pushes waves to the pool simulating ocean environment under hurricane.

Concrete spalling was observed around late July of 2021 by the staff of the facility. Further examination found diagonal crack lines on the surface of DT stems, as well as crack lines at the bottom of stems. The pool hall has been closed since this discovery. A two-person structural engineering team from WSP arrived at the site of incident on August 12, 2021. Using an electrical lift, they surveyed the DT bearing locations where access permitted around existing equipment.

After the initial inspection, WSP obtained from the CG the original AE design drawings, precast wall and

DT shop drawings with design calculations. The investigating team first focused on the DT member design and the bearing details. By studying the A/E drawings, the team then focused on to the wave generating chamber.

After a series of correspondence with the CG, a team of three, two structural engineers and an architect, arrived at the site on September 14, 2021 for the second inspection focusing on the wave chamber, and completing the observation record inside the RS Pool room.

Analysis of the above information yielded the following conclusion:

1. The double tee stem was designed as unreinforced for bearing stress, but there is an error in the original precast design calculation, resulting in under strength in the bearing zone of the stem.

2. Middle portion of the south bearing wall sits on the pool structure that is subjected to direct wave vibration. The vibration propagates across the entire south wall, causing cyclical movement between the DT and corbel. This action had led to:

a. The elastomeric bearing pad failure and/or walk-off between the bottom of tee and corbel. The absence of a competent bearing pad led to stress increase in the DT’s bearing zone (strength decrease) then shear failure evident with concrete cracking among DTs at the south end. The progression of this type failure could lead to sudden collapse of the entire structure.

b. The precast wall panels over the wave chamber have been seriously damaged by the vibration. This condition makes the building more prone to collapse than that of cracked DT’s only.

c. The vibration has also led to subgrade consolidation under the slab-on-grade. The floor has crack lines and there are reported soft spots.

3. Concrete casting quality is poor at the lower region of the double tee stems.

Honeycombs are seen around most of the DTs, especially near the bearing zone. The steel bearing plate and its anchor bar inside the DT rusted and expanded as a result.

This is evident among many DTs at the north end. It will lead to eventual bearing failure as well.

4. Shear reinforcement inside the DT stem is found insufficient per building code criteria, though it is not a contributor to the current structural failure at bearings. This deficiency has not manifested itself because the roof has not been loaded to the designed limit, and because the code imposes a higher factor of safety for concrete that is not reinforced for shear. This higher factor of safety is due to the sudden brittle failure of concrete beams without sufficient shear reinforcement, shear failure in these areas would occur without prior warning.

WSP recommends the following immediate actions:

1. The entire Building 3 facility must be closed for normal operation, except for individuals needing quick access. The reason is that though the shear failure concern is identified on only the double tees of the RS Pool, the roof slab (flange of the tees) is connected to the load bearing wall shared by all rooms surrounding the RS Pool. A collapse of the long span double tee over the RS Pool may pull the walls, and compromise supports of the double tees over the adjacent rooms.

2. The wave generators, for both small and big pools, must not be turned on.

3. Provide temporary shoring to each end of each DT stem inside the RS Pool. The shoring posts will bear on the edge of the pool which is about 13 feet from the bearing walls. When the shoring is complete and approved by WSP engineers, the following can proceed:

a. All areas of Building 3, except RS Pool, can resume normal operation. Wave machine in the UMET pool, east of RS Pool room, can be turned on. The original design drawing does not indicate there is vibration interference to the building structure from the UMET pool wave generator. An A/E evaluation of the entire facility is recommended to confirm its safe serviceability, before the opening of

Building 3, after the RS Pool room has been shored.

b. The shoring system provides a safe condition for up close inspection of the DT for any reason. But it will require removal of all equipment on the pool deck and above.

c. The shoring system and the removal of equipment inside provide the condition for retrofit construction if the CG decides to proceed.

WSP proposes the following technical approach to restore the RS Pool room with its intended function without affecting the rest of Building 3 beyond the RS Pool room.

1. Remove the 110 feet long DTs over the RS Pool and remove the wall panels over the wave chamber.

2. Build a steel girder spanning over the wave chamber, approximately 75 feet in span length.

3. Rebuild the roof structure with long span (110 feet) steel joists, with metal deck filled with 4 inches concrete to counter the wind uplift pressure.

4. Rebuild the south wall at the wave chamber area. The wave chamber with its machinery will be isolated from the building.

Structurally, the rest of Building 3 is safe to be operational during construction proposed above. There could be periods of shut down due to large crane operation when the DTs are being removed, and the long steel joists are being erected.

The ROM estimated construction cost is $7.73 million. The design duration would take 6 to 8 months.

Construction duration is approximately 18 to 24 months.

2 STRUCTURAL ASSESSMENT

2.1 EXISTING CONDITIONS

Building #3 Rescue Swimmer Training Facility was designed around year 2010, construction completed in

2012 per precast design record and close-out drawing records. The building structure is single story, all structurally interconnected. The structural system is precast double tee roof beam sitting on precast insulated walls (sandwiched panels). In the area surrounding the RS Pool room, the DT span length ranges from 50 to 60 feet which is the typical fabrication range in the precast industry.

Over the RS Pool room, the DT span length is 110 feet. The cross section is 3’-11” deep, in light-weight concrete. Bottom of DT is 25 feet above pool deck. Double tee construction in such span length and section depth is not typical. The design is well beyond the available load tables in the PCI Design Handbook which is the precast industry standard. The design calculation is in the owner’s record and was provided to the WSP team for review.

There is a wave generating chamber along the south side of the RS Pool. Load bearing walls there rest on the wave chamber concrete beams. It was reported by the facility staff that the walls shake when the wave fans are turned on.

The much smaller UMET Pool in the adjacent roof also has wave generation. But the mechanism is isolated from the load bearing elements including foundation. This pool is not a concern for structural safety.

Since the discovery of spalling concrete and crack line on the DT stems over the RS Pool, this room is closed until further notice. WSP engineering team conducted an emergency site visit on August 12, 2021. Using an electric scissor lift, engineers were able to have close examination to about one quarter of the DT bearing zone.

Equipment on the pool deck and above prevented a full documentation of each stem’s condition up close.

WSP analyzed the photographs from the site, record drawings including architectural, structural, pool consultant and MEP, as well as shop drawings of precast walls and double tee along with precast design calculations.

A second site inspection was planned afterwards on September 14, 2021. Its focus was the wave generating area, both interior and exterior, as well as a complete documentation of the DTs from ground level, and all surfaces of

RS Pool room which are pertinent to the scope of the proposed restoration.

2.2 REPORT OF FINDINGS

2.2.1 VISUAL SURVEY

The engineering team recorded the conditions at bearing zone of each DT at each end, the bearing wall condition at the south side and Pool Mechanical room. The inspections documented, but were not limited to, bearing pad position, cracks and its direction on the tee stem, rusting, concrete voids, spalling, etc. The additional concerning findings on the south wall panels and the mechanical room were not expected by the team, as they were not documented in the task RFP SOW. A complete check list and corresponding photos are in Appendix A. The figures referenced (Fig. xx) in the following are typically in Appendix A, unless noted otherwise.

Here are major findings by visual observations:

1. There are cracks in both vertical and 45-degree direction initiated at the bearing of the precast double tee. (Fig. 41, 42 and 50)

2. There are breakouts or spall at the bearing of the double tees. (Fig. 49)

3. Where concrete has fallen out, reinforcing steel, besides the post-tension strands, was not visible as typically expected. (Fig. 51)

4. Elastomeric bearing pads under the double tee stem is either crushed, or/and slipped out from the tee stem. (Fig. 40, 51)

5. In some cases, the concrete corbel supporting the double tee has spalled. (Fig. 49)

6. Rust is bleeding to the bottom of DT stem near the bearing. (Fig. 20 through 33)

7. Concrete quality is poor at the lower region of the double tee. Honeycombs are visible, though masked by the heavy coat of white paint. (visible among most photos)

8. The portion of south wall over wave chamber (approximately 70 feet long) is seriously damaged with many cracks throughout its height and width. The large cracks have been sealed superficially

(Fig. 73, 74). The cracks have resulted in steel reinforcement inside the wall to rust and bleeding to the surface. This segment of wall panels exhibits discoloring associated with wide-spread water intrusion. (Fig. 79, 80, 81)

9. The south wall panels at each side of the wave chamber (Pool Mechanical room) also exhibit long crack lines and rust dots. (Fig. 84, 85)

10. The floor slab of the Pool Mechanical room has cracks around machine anchoring area. The wave generator is mounted to the building load bearing wall directly. (Fig. 76)

11. Portion of the pool deck aligned with the wave chamber is broken off from the rest of pool deck.

(Fig. 82, 83)

Item 1 to 5 above appear in both the south and north bearings. The worst damage occurred above the wave generation chamber under the middle half of the south wall; item 6 concentrates at northeast region; and item 7 is common throughout the length of tee stems at the lower portion.

Item 8 to 11 are within the limit of the wave chamber. It was discovered during the second round of inspection. The examination of the design document pointed the investigating team to this area.

It was curious at first impression that the size of elastomeric bearing pads for the exceptionally long DTs is the same as the typical DTs adjacent to the RS Pool room. It was expected that larger bearing pads would be used for the longer spans due to the increased loading.

It was reported that whenever the RS Pool wave fans were turned on, the “whole building” shook with loud noise. It was also reported by chance, that water with color of rust gushed out of a punctured hole on the insulating precast wall in the UMET Pool room (Fig. 89). This was recorded even though the bearing wall in this room (a smaller pool room next to the RS Pool room) was not part of this investigation. The condition of the insulated panels may need a complete, in-depth investigation in the near future to assess their current condition. More is discussed in section 2.2.4.

2.2.2 ANALYSIS OF PRECAST DOUBLE TEE DESIGN

By analyzing the record drawings and design calculation, WSP concluded that the RS Pool roof beams (DT stems) have suffered shear failure and concrete bearing failure at bearing to various degree, from total failure (large concrete breakout) to eminent failure (cracks to form soon). The uncracked stems are currently carrying increasingly higher stress from the loss of load support of the cracked stems.

There is a calculation error in the original DT design resulting in an unreinforced bearing region at each end of the DT stem. The as-built bearing strength is inadequate per design code. It is common for design engineers to provide notional reinforcing steel at the bearing zone for DTs of typical length and depth. For an atypical DT of

110 feet long and 4 feet deep, it would have been standard practice to provide shear reinforcing even though the mistaken calculation resulted no reinforcing needed. The unreinforced concrete stem has no redundancy when certain factors cause cracking in the concrete.

Another premise of the unreinforced bearing zone design is the sliding effect of the bearing pad. Per guidance in PCI Design Handbook, the bearing pads used for the RS Pool DTs are wrong in both area and thickness.

This led to the crush failure of the bearing pad and walk-off easily from DT’s movement in various conditions.

Once the concrete bottom of the DT lost the sliding effect from the elastomeric pad, whether due to crush failure or walk-off of the bearing pad, the horizontal forces caused by movement increase due to the higher concrete friction coefficient, thus the bearing strength decreases. Many of them have already failed with diagonal and vertical cracks and concrete spalls. Spalling and cracking of the concrete within the bearing area also causes losses in the prestressing forces at the ends of the beams, which weakens the beams in shear and causes further failure.

Review of the precast design calculation also reveals that shear reinforcing was not adequately provided per its own output data. The steel mesh called out in the calculation markup should have been 33 feet long from support instead of 12 feet. In addition, the wire mesh was not indicated in the precast shop drawing, and it is not visible inside the broken concrete section. The beam shear reinforcing deficiency has not manifested itself, because the roof live load has never been loaded to the design load level.

The depth of DT is 47 inches, much deeper than the typical sections from load tables found in PCI Handbook and manufacturers’ catalogs. The risk in casting concrete for such a deep section is separation of coarse aggregates from water and cement, unless an effective concrete consolidation procedure was implemented. It is evident that the lower half of DT stem has small voids on the surface, more concentrated near the bottom; looking at the broken concrete at bearing, the number of coarse aggregates appears to be unusually concentrated.

Aggregate-cement separation has degraded the concrete strength which affects all strength criteria, besides bearing strength. The many voids near the bottom of DT have allow moisture with high chloride infiltrated the concrete section. It is evident that in many stems, rust is bleeding through the bottom near the support where there is a steel bearing plate with welded anchor bar, and it has corroded. The prestress strands have not yet corroded because they are made of corrosion resistant steel; however, corrosion will eventually also occur in the prestress strands.

The rust of steel bearing plate and dowel rebar inside the DT stem expands and crack open the concrete, which is evident with crack lines along bottom of the stems. This will lead to shear failure of the DT section, if not yet occurred. Had the steel bearing plates and the dowel bar been galvanized, considering that the position of the plates would be exposed to chloride moisture, the rusting could have been avoided.

It should be pointed out that the prestress inside the DT – the key factor for the flexural strength of the beam, has been weakened to some degree due to the concrete cracks at the end zone. But the loss is expected to be a small percentage of the total pre-compression force.

2.2.3 ANALYSIS OF BUILDING DESIGN

The defects in the design and fabrication of the long-span precast double tees (DTs) would eventually show signs of corrosion and diagonal cracks over time. But it would not have occurred shortly after the pool went in service if not triggered by the direct vibration from the waves generating mechanism.

The middle half of the south load bearing wall (insulated precast panels) bears on a concrete beam that is part of the wave generating chamber structure. The building structural designer delegated it to the pool designer. The pool structure, including the wave chamber was designed by a pool consultant independent of the building architect and structural engineer, as well as the precast member designer. It does not appear that the wave vibration issue was coordinated and addressed among the various disciplines of the design team.

The cyclic water vibration stirred up by the series of wave fans hits the pool beam and its supporting caisson directly; in turn shakes the precast wall sitting on the pool beam. The precast panels are inter-connected by welding of steel embeds throughout the building. This is why the building shook when the wave was turned

on. The south RS Pool wall experienced the most shaking, resulting the bearing pad slipped and crushed under the DT bearing. The absence of bearing pad, with continual relative movement between the DT and bearing wall, led to stress increase in the bearing zone of DT, and shear cracks on the stem. This phenomenon is typical among bearings at the south side.

The walls themselves have been subjected to damage since the start of the RS Pool operation. Even if precast DT had been designed and fabricated perfectly correct, the progression of cracking due to vibration in the wall panels could have resulted in structural failure. The sudden collapse of the load bearing could have potentially led to casualties.

Most of the south side wall panels exhibit cracking and rusting. The ones outside the wave generation room are less damaged than the ones within. Further study is needed to determine whether these less damaged wall panels need to be replaced.

As a design principle, any source of vibration should be isolated from the building structure – from foundation to load bearing (vertical and lateral) members and to roof framing. The wave chamber should not have been designed as the foundation of the building structure.

2.2.4 OTHER ISSUES

Floor slab cracking around wave chamber area could be the result of vibration as well, although this is a serviceability issue, not affecting the building structure. The floor structure should have been designed properly to avoid random cracking.

The inspection team saw rusted water stained from a small hole on the north wall of the UMET Pool room.

The facility staff reported that rusted water streamed out when the hole was drilled for wiring. The rusting color could be a result of steel wire corrosion. Though the source of the water is unknown, a cursory observation on the roofing condition did not indicate there is waterproofing concern on the roof. It is our recommendation that the condition of the insulated panel may need a complete investigation in the near future.

2.2.5 SUMMARY OF THE INVESTIGATION

The vibration from the wave generating system which is attached to the building’s load bearing system has undermined the structural walls and the roof framing structure. In our opinion, a lack of coordination among the original design disciplines resulted in a design mistake

The deficiency of the roof double tee, in both design and fabrication, accelerated the revelation of structural failure.

The damaging action to the precast walls and the DTs started as soon as the wave fans became operational.

The failure of bearing pad led to failure of the concrete stem starting from those that sustained the most vibration. The not-yet failed DTs in turn carried increased loading. The subsequent wave action would cause further failure to the DTs, and the remaining members would be more and more stressed. The cycle eventually would lead to collapse of the roof DTs over the RS Pool. The DT collapse would pull down the wall panels that are supporting the DTs over the rooms surrounding the RS Pool. There would be a progressive collapse to the entire Building 3.

It is also possible that the load bearing walls over the wave chamber would collapse before the roof structure.

Based on this analysis, an immediate plan of action is recommended in the next chapter, and a scheme of restoration of the RS Pool room is proposed in the following chapter.

3 PROPOSED RESTORATION

3.1 IMMEDIATE ACTIONS RECOMMENDED

The objectives of the immediate action are to first prevent further development of the structural cracks over the RS Pool; allow the remainder of Building 3, other than the RS Pool room, to operate normally; and provide a safe condition inside RS Pool room for necessary clearing and further inspection.

1. The entire Building 3 facility should be closed for normal operation, except for individuals needing quick access. There should be no access to this building when:

sustained wind speed is over 35 mph, during heavy rain, or if there is snow on the roof.

The building should remain closed until recommendation item 2 is implemented and completed.

2. Provide temporary steel shoring posts under each end of each DT stem. The posts shall be bearing along the concrete reinforced pool edge of north and south. A design of the shoring, including layout plan, post size, bracing etc. must be produced by a professional engineer. The shoring system shall be compatible with future actions on this structure.

3. Once the shoring system is in place and inspected, Building 3 can resume normal operation, except the RS Pool room, where safe access should be limited to restoration work only.

Shoring of the concrete walls is not required. The beam shoring will be capable of fully supporting the weight of the DT’s and not relying on walls for support. Additionally, failure of the exterior walls in the short term is not anticipated as long as the wave generation machine is not turned on.

3.2 PROPOSED SCHEME OF RESTORATION

The extensive deficiency in the precast double tee would make the repair of it very expensive yet structurally ineffective in the long term. The deterioration in middle portion of the south wall requires its removal and replacement. The wave chamber must be isolated from the building structure. Roof framing that can span over the wave chamber must be light weight enough to be constructible.

Taking into account the above factors, WSP recommends replacing the RS Pool roof structural system with steel joists bearing on the existing precast wall; have a steel girder spanning over the wave chamber to support the roof joists in this zone; the partition wall between the wave mechanical room and RS Pool room will sit on the wave chamber but isolated from the building structure.

3.2.1 DEMOLITION

Demolition is expected to be in the order stated below and shall follow engineering design drawings and specification.

1. Temporarily terminate and remove all service lines of FP and MEP in the RS Pool room. It should be designed to maintain normal service to the rest of the building.

2. Temporarily remove all mechanical equipment in the wave generation room.

3. Remove roofing over the RS Pool room. Roofing over adjacent rooms is not expected to be affected.

4. Provide temporary lateral bracing to the south wall of RS Pool room.

5. Demolish enclosure of Pool wave generation.

6. Remove the 110 feet long DTs over the RS Pool.

7. Remove the wall panels over the wave chamber, and possibly the entire south wall. This will not affect the structural stability of Building 3.

8. Remove shoring system set up earlier under the DT stems.

3.2.2 NEW ROOF STRUCTURE

1. Install steel columns east and west of the wave chamber. Existing foundation may need modification.

2. Erect open-web steel joist girders spanning over the wave chamber, sitting on the new steel columns.

3. New precast insulating will be installed if existing ones need to be replaced.

4. Erect open-web steel joists spanning between north and south wall.

5. Install metal roof deck. A concrete pour of 4 inches (+/-) is expected to counter the wind uplift.

6. Install connections between roof deck and surrounding wall panel to restore the lateral load resisting load path.

7. Install light gage wall framing over Pool Mechanical room.

3.2.3 RESTORATION

1. Restore roof taper insulation, reset roof drains as original designed, and install waterproofing as originally designed.

2. Build an isolated enclosure for the pool wave generation room. Reinforced CMU wall will separate the RS Pool room and Pool Mechanical room, sitting on the wave chamber but not attached to the RS Pool room structure. The entire enclosure of the mechanical room will be self-contained, although subjected to vibration, will not affect the main building

3. Exterior wall above the wave generation room will be insulated metal panels attached to light gage studs hanging from the joist girder. The steel panel wall has an expansion joint with the roof of wave generation room. Special attention will be paid to integrate, even enhance the aesthetics of the south wall of Building 3.

4. Restore equipment of wave generation room.

5. Restore interior FP, MEP and other equipment in RS Pool room.

Structurally, the rest of Building 3 is safe to be operational during construction proposed above. There could be periods of shut down due to large crane operation when the DTs are being removed, and the long steel joists are being erected. Depending on contractor’s cooperation, the shut-down is estimated 3 to 4 weeks at a time. The design duration would take 6 to 8 months. Construction duration is approximately 18 to 24 months.

3.3 COST ESTIMATE

Please refer to Appendix C for worksheet of cost estimate.

REFERENCES

· USCG provided drawings and calculations:

o As-Built Structural Drawings dated 2012 (16 pages) o As-Built Architectural Drawings dated 2012 (67 pages) o As-Built Pool Drawings dated 2012 (31 pages) o Double T Framing and Details Shop Drawings dated 2010 (6 pages) o Precast Wall Panel Shop Drawings dated 2009 (48 pages) o Precast Design Calculations dated 2010 (543 pages)

· UFC 3-301-01 - Unified Facilities Criteria Structural Engineering

· IBC 2015 – International Code Council, 2015 International Building Code

· ASCE 7-10 - American Society of Civil Engineers, 2010 Minimum Design Loads for Buildings and Other Structures

· ACI 318-14 - American Concrete Institute, 2014 Building Code Requirements for Structural Concrete and Commentary

· PCI – Precast Concrete Institute, Design Handbook, Sixth Edition

· TMS 402-15 - The Masonry Society, 2015, Building Code Requirements and Specification for Masonry Structures

· AISC – American Institute of Steel Construction, Manual of Steel Construction, Fourteenth Edition

· SJI-COSP-10 – Steel Joist Institute, 2010, Code of Standard Practice for Steel Joists and Joist Girders

· ANSI/SDC RD-210 – Steel Deck Institute, 2010, Standard for Steel Roof Deck

APPENDIX

A. SITE

INVESTIGATION

PHOTOGRAPHS

USCG Elizabeth City Building 3 RS Pool Room Appendix A

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Figure 51: S14_3

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Figure 80: W9

Figure 81: W10

Figure 82: W11

Figure 83: W12

Figure 84: W13

Figure 85: W14

Figure 86: W15

Figure 87: Interior

Figure 88: Roof Coping

Figure 89: Water Gushing Out of Wall

B. REFERENCE

DRAWINGS

Chiang Oval

Chiang Callout

POOL MECHANICAL ROOM

Chiang Callout

WAVE CHAMBER

Chiang Callout

POOL MECHANICAL ROOM

Chiang

WAVE CHAMBER

Text Box

DOUBLE TEE LAYOUT PLAN

Chiang Text Box

RS POOL ROOM

Polygon Line

Cloud

Chiang

POOL RELATED FOUNDATION IS NOT COVERED BY THIS STRUCTURAL DRAWING

Chiang Oval

Chiang

BUILDING STRUCTURAL DESIGN LEFT THE BEARING WALL SUPPORT TO OTHERS

LOAD BEARING WALL SUPPORTED BY WAVE CHAMBER BEAM SUBJECTED TO DIRECT WAVE VIBRATION

Chiang Text Box

WAVE CHAMBER

Chiang Callout

WAVE GENERATOR MOUNTED ON FLOOR AND BEARING WALL

Chiang Line

Chiang Line

Chiang Arrow

Chiang Text Box

POOL STRUCTURE

Chiang Callout

POOL STRUCTURE IS DESIGNED BY A SEPARATE ENTITY

Chiang

WATER VIBRATION HITS ON THE LOAD BEARING WALL BASE AND ITS SUPPORTING BEAM

C. COST ESTIMATE

Building 3 Rescue Swimmer Training Facility

USCG Base Elizabeth City

Elizabeth City, NC

95% Submittal Cost Estimate

October 25, 2021

Prepared for:

WSP USA Solutions, Inc.

96 Morton Street 8th Floor

New York, NY 10014

520 Kirkland Way, Suite 301 Kirkland, WA 98033 tel: (425) 828‐0500 fax: (425) 828‐0700 www.prodims.com

M as te r

E st im at e S u m m ar y

Name: Building 3 Rescue Swimmer Training Facility Second Name: USCG Base Elizabeth City Location: Elizabeth City, NC

520 Kirkland Way, Suite 301 Design Phase: 95% Cost Estimate Kirkland, WA 98033 Date of Estimate: October 25, 2021 tel: (425) 828‐0500 Date of Revision:

fax: (425) 828‐0700 Month of Cost Basis: October, 2021 www.prodims.com

Direct Cost with Markups

(See Detail Below)

Total Estimated Construction Cost

$4,367,511 69.04% $7,382,885

$66,286 69.04% $112,051

Markups for the Cost Estimate:

Scope Contingency 20.0%

General Conditions 16.0%

Home Office Overhead 6.0%

Profit 6.0%

Escalation to January, 2023 8.08%

Markups - Cumulative 69.04%

Estimate Assumptions:

The estimates are based on the team design information received by 9-23-21 and 10-21-21 on the shoring towers

The estimates does not include any Hazardous Material Abatement Costs as it is not defined.

Escalation rate of 6.0% per year is included. Costs are escalated to the midpoint of construction of January, 2023

The Escalation Rate above 6% per year is not included in the estimate. This is important if construction escalation rate exceeds this rate after the date of this estimate. The estimate should be recalculated if escalation rates increase and/or if this estimate is older than six months.

Estimate Qualifications:

The estimate is not be relied on solely for proforma development and financial decisions

Summary sheet markups are cumulative, not additive. Percentages are added to the previous subtotal rather than the direct cost subtotal.

Estimated labor is based on an 8 hour per day first shift 5 days a week. Accelerated schedule work of overtime has not been included.

Estimate is based on a competitive public bid with at least 3 bona fide submitted and unrescinded general contractor bids.

If only 1 or 2 bids are received the bids could be 40% to 100% more than the cost estimate based on empirical experience.

Estimate is based on a competitive public bid with a minimum 6 week bidding schedule and no significant addendums within 2 weeks of bid opening.

Estimated construction cost is for the entire project. This estimate is not intended to be used for other projects.

Division 0/ Division 1 specifications are presumed to have normal ranges for liquidated damages, construction schedule and terms & conditions.

These divisions are typically written after the final estimate. Please contact the cost estimator for a review, if desired.

Please consult the cost estimator for any modifications to this estimate. Unilaterally adding and deleting markups, scope of work, schedule, specifications, plans and bid forms could incorrectly restate the project construction cost.

The construction cost estimate does not include an estimate of owner soft costs such as taxes, A/E fees, owner contingencies and permit fees.

Construction reserve contingency for change orders is not included in the estimate.

Sole source supply of materials and/ or installers typically results in a 40% to 100% premium on costs over open specifications.

The estimate includes a reasonable construction escalation that can be determined based on market conditions for up to the next 6 months.

Since this project has a midpoint of construction further than 6 months, increases in escalation are not included beyond the rate shown in the estimate.

Estimate Summary

Building 3 Rescue Swimmer Training Facility

Steel Shoring Towers at Building 3 Pool Roof Swimmer Training Facility

E st im at e D et ai l - B u ild in g

R es cu e S w im m er

T ra in in g

F ac ili ty

Building 3 Rescue Swimmer Training Facility Areas sqft

Building 3 Rescue Swimmer Training Facility Building Area 52,048

Elizabeth City, NC

520 Kirkland Way, Suite 301 95% Cost Estimate

Kirkland, WA 98033 October 25, 2021

Phone: 425‐828‐0500 Fax: 425‐828‐0700 www.prodims.com October, 2021 Total Area 52,048

Direct Cost of Construction

WBS Description Quantity U of M Labor Labor Total Material Material Total Equipment Equipment Total Total $/U of M Direct Cost Cost/SQFT

0.06

Foundations

New Foundations at each end of New Girder at Wave Pool - Includes Selective Demolition of Existing Building Systems 2 each 9,150.00$ 18,300.00$ 5,850.00$ 11,700.00$ 900.00$ 1,800.00$ 15,900.00$ 31,800.00$

Substructure

New Structural Slab on Grade System with Underslab Fill, Reinforcing and Finishing on South Side Pool Deck 2,955 sqft 17.08$ 50,471.40$ 10.92$ 32,268.60$ 1.68$ 4,964.40$ 29.68$ 87,704.40$

Demolition of Existing Slab on Grade System at South Side Pool Deck 2,955 sqft 4.00$ 11,805.23$ 0.26$ 753.53$ 0.26$ 753.53$ 4.51$ 13,312.28$

Superstructure Roof Systems

Remove Existing Precast Double Tee Structural Roof System Including Topping Slabs 21,670 sqft 12.32$ 266,974.40$ 1.68$ 36,405.60$ 4.20$ 91,014.00$ 18.20$ 394,394.00$

Structural Metal Deck with 4" Concrete Fill Roof Deck on New Bar Joists 21,670 sqft 3.38$ 73,136.25$ 2.88$ 62,301.25$ 0.38$ 8,126.25$ 6.63$ 143,563.75$

Structural Steel - New Bar Joist System - Large Span and New Connection to Existing Building - Use Existing Vertical Structure of Building 21,670 sqft 22.28$ 482,699.25$ 18.98$ 411,188.25$ 2.48$ 53,633.25$ 43.73$ 947,520.75$

Structural Steel - New Girder at Wave Pool 75 lnft 421.20$ 31,590.00$ 358.80$ 26,910.00$ 46.80$ 3,510.00$ 826.80$ 62,010.00$

Exterior Closure Exterior Wall System

New Exterior Wall System - Composite System Horizontally and Vertically - Double Wythe 8" CMU with Cold Formed Metal Studs with Brick Veneer, Metal Panels, Rigid Insulation and Expansion Joints 2,625 sqft 47.58$ 124,897.50$ 30.42$ 79,852.50$ 4.68$ 12,285.00$ 82.68$ 217,035.00$

Remove Existing Exterior Wall System - Existing Precast Wall System - Deconstruction - Add/Remove Temporary Shoring of Wall to Remain 2,625 sqft 12.32$ 32,340.00$ 3.68$ 9,660.00$ 0.96$ 2,520.00$ 16.96$ 44,520.00$

Roofing System

EPDM Low Slope Roofing System with Coverboard, Rigid Insulation system, Vapor Retarder, Flashing and Trim, Interior/Scupper Overflow Roof Drainage - Complete System 21,670 sqft 12.11$ 262,326.19$ 9.90$ 214,630.52$ 1.32$ 28,617.40$ 23.33$ 505,574.10$

Remove Existing Low Slope Roofing System at Precast Structural System - Allow for Tempoary Weather Protection of Roof 21,670 sqft 3.46$ 74,934.86$ 0.34$ 7,411.14$ 0.23$ 4,940.76$ 4.03$ 87,286.76$

Month of Cost Basis:

Date of Revision:

Name:

Second Name:

Location:

Design Phase:

Date of Estimate:

WBS Description Quantity U of M Labor Labor Total Material Material Total Equipment Equipment Total Total $/U of M Direct Cost Cost/SQFT

0.06

Interiors Interior Finishes System

Wall Finishes

Interior Finish System of New South Wall 2,625 sqft 2.20$ 5,775.00$ 1.80$ 4,725.00$ 0.24$ 630.00$ 4.24$ 11,130.00$

Acousticall Wall Panels at South Wall - Allowance 1 set 2,880.00$ 2,880.00$ 6,720.00$ 6,720.00$ 576.00$ 576.00$ 10,176.00$ 10,176.00$

Floor Finishes

New Pool Deck Finish at New Structural Slab 2,955 sqft 5.04$ 14,893.20$ 8.96$ 26,476.80$ 0.84$ 2,482.20$ 14.84$ 43,852.20$

Ceiling Finishes

Paint Exposed Structure and Systems 21,670 sqft 4.23$ 91,664.10$ 0.27$ 5,850.90$ 1.08$ 23,403.60$ 5.58$ 120,918.60$

HVAC Systems

HVAC - Remove and Reinstall Ductwork System - TAB and Recommission System 21,670 sqft 5.40$ 117,018.00$ 6.60$ 143,022.00$ 0.72$ 15,602.40$ 12.72$ 275,642.40$

Fire Protection Systems

Wet Pipe System - Remove and Reinstall - Reccommsion System 21,670 sqft 2.34$ 50,653.63$ 1.91$ 41,443.88$ 0.26$ 5,525.85$ 4.51$ 97,623.35$

Electrical Systems Electrical Service, Branch Wiring and Lighting

Remove and Reinstall New Power Systems as Required for Roof and South Wall Work 21,670 sqft 1.10$ 23,837.00$ 0.90$ 19,503.00$ 0.12$ 2,600.40$ 2.12$ 45,940.40$

Remove and Install New Lighting System - Complete 21,670 sqft 7.70$ 166,859.00$ 6.30$ 136,521.00$ 0.84$ 18,202.80$ 14.84$ 321,582.80$

Low Voltage Systems - Communications, Data, Wi-Fi, Fire Alarm, Security, Audio, Video Systems, Lightning Protection System - Remove, Store and Reinstall System - Recommission System 21,670 sqft 1.07$ 23,264.91$ 0.15$ 3,172.49$ 0.11$ 2,379.37$ 1.33$ 28,816.77$

Fire Alarm System - Remove and Reinstall Devices and New Wiring - Recommission System 21,670 sqft 1.74$ 37,705.80$ 1.26$ 27,304.20$ 0.27$ 5,850.90$ 3.27$ 70,860.90$

Equipment - Kitchen, Industrial, Seating, Built in Furnishings, etc.

Maintain and Preserve and/or Remove and Reinstall Existing USCG Training Equipment at Pool - Floor, Wall and Roof Mounted Systems - Allowance 21,670 sqft 11.25$ 243,787.50$ 3.75$ 81,262.50$ 2.70$ 58,509.00$ 17.70$ 383,559.00$

Maintain and Preserve Existing Pool System Including Equipment - Temporary Cover/Scaffolding/Debris Protection - Allowance 21,670 sqft 7.50$ 162,525.00$ 2.50$ 54,175.00$ 1.80$ 39,006.00$ 11.80$ 255,706.00$

Remove, Store and Reinstall Wave Generator System - Allowance 1 each 121,698.11$ 121,698.11$ 19,811.32$ 19,811.32$ 25,471.70$ 25,471.70$ 166,981.13$ 166,981.13$

Subtotal of the Direct Cost of Construction Building 3 Rescue Swimmer Training Facility 4,367,511$ 83.91$

E st im at e D et ai l - T em p o ra ry S h o ri n g a t B u ild in g

P o o l R o o f S w im m er

T ra in in g F ac ili ty

Building 3 Rescue Swimmer Training Facility Areas sqft

Steel Shoring Towers at Building 3 Pool Roof Swimmer Training Facility Building Area 52,048

Elizabeth City, NC

520 Kirkland Way, Suite 301 95% Cost Estimate

Kirkland, WA 98033 October 25, 2021

Phone: 425‐828‐0500 Fax: 425‐828‐0700 www.prodims.com October, 2021 Total Area 52,048

Direct Cost of Construction

WBS Description Quantity U of M Labor Labor Total Material Material Total Equipment Equipment Total Total $/U of M Direct Cost Cost/SQFT

0.06

Superstructure Roof Systems

Temporary Shoring Towers - 2" Steel Pipe, Beam Seats, Pipe Feet, Bracing, Shop Primed and Installed On Site - Removed and Salvaged After Double Tee Demolition 14.21 ton 2,684.00$ 38,145.90$ 1,716.00$ 24,388.36$ 264.00$ 3,752.06$ 4,664.00$ 66,286.32$

Subtotal of the Direct Cost of Construction Steel Shoring Towers at Building 3 Pool Roof Swimmer Training Facility 66,286$ 1.27$

Name:

Second Name:

Location:

Design Phase:

Date of Estimate:

Date of Revision:

Month of Cost Basis:

D. STRUCTURAL

CALCULATION

PACKAGE

Table of Contents

Part I Load Input

Part II Bearing

II-1 Min reinforcement

II-2 Unreinforced Bearing

II-3 Bearing Pad

II-4 Original Calculations

Part III Shear

III-1 Web Shear

III-2 Shear Reinforcement

III-3 3D Original Shear Calculation

WSP USA

Elizabeth City CSRP

Calculated By: MWW 09/02/2021

12DT47 Calculations

Input γConc 110pcf:= concrete density

Area 1075in2 := Double T area

Depth 47in:= Double T depth

Stem Width:5in Stem Width

Span 110ft:=

Loading

SDL 15psf:= Superimposed DL

LL 20psf:= Roof LL

WSelf Area γConc 12ft

× 68.43 psf×=:= Self Weight of DT

TribStem 6ft:= Stem Trib area

Loading per each stem

VDL SDL

Span

× TribStem WSelf

Span

× TribStem×+ 27.53 kip×=:= End dead load

VLL LL

Span

× TribStem 6.6 kip×=:= End Live load

Vu 1.2 VDL× 1.6 VLL×+ 43.6 kip×=:= Ultimate end load

VASD VDL VLL+ 34.13 kip×=:= ASD End loading wildem1

Part I Load Input

Calculated By: MWW 09/02/2021

Bearing Strength Use PCI design handbook

Vu 43.6kip:= Bearing Load

Nu 0.2 Vu× 8.72 kip×=:= 0.2*Bearing Load (PCI Recommended) λ 0.75:= Lightweight concrete factor fc 5000psi:= Concrete strength

Check 4.3.6 fror min reinforcement ϕ 0.75:= safety factor fy 60ksi:= steel yield stress

Acr 48in 5× in 240 in2 ×=:= stem width*height μ 1.4 λ× 1.05=:= table 4.3.6.1 μe min

1000 λ× Acr in2 × μ×

Vu lbf

3.4, æ ç ç ç ç è ö ø

3.4=:= Eq. 4.3.6.2

Eq. 4.3.6.1 Avf

Vu ϕ fy× μe×

0.28 in2

Additonal rebar needed for axial tenson

An Nu ϕ fy×

0.19 in2 ×=:= Eq. 4.3.6.3

Avf An+ 0.48 in2 ×= Minimum reinforcement

(1)#5 bar is provided with an area od 0.31in^2 which does not meet the minimum equiered for unreinforced bearing wildem1 Text Box Part II Bearing wildem1

II-1 Min Reinforcement

Calculated By: MWW 09/02/2021

Check 4.6.1 for Unreinforced bearing

Since minimum reinforcement for section 4.3.6 and 4.6.2 is not provided cr does not equal 1.

4.6.1 recommends minimum of Nu/ϕfy, cac package states minimum requiered is 0.117in^2.

ϕBrg 0.65:= safety factor s 4in:= distance to edge w 5in:= bearing width sw min s w× 9in2 ,( ) 9 in2 equation used because reinforcement not provided per 4.6.2Cr sw

200in2 æ ç è ö ø

Nu Vu

0.54=:=

A1 18in2 := bearing area per calc package

A2 22.5in2 := lower base area per calc package ϕVn ϕBrg Cr× 0.85 fc× A1×( )× A2 A1

× 29.9 kip×=:= Eq. 4.6.1.1

Vu ϕVn

1.46=

Bearing is almost 50% overloaded due to end shear and horizontal loading caused by movement. Original designed relied on reinforcment that does not meet the minimum criteria.

Check bearing after Pad Failure

If bearing pad fails the stem will be directly loaded onto the concrete corbal and the lateral load factor will be based on the coefficient of friction for concrete to concrete (0.6) which is much higher than the 0. used for concrete slipping on the bearing.

Nu2 0.6 Vu× 26.16 kip×=:=

Cr2 sw

200in2 æ ç è ö ø

Nu2 Vu

0.16=:= ϕVn2 ϕBrg Cr2× 0.85 fc× A1×( )× A2 A1

× 8.65 kip×=:= Eq. 4.6.1.1

Failure of the bearing pad will cause the bearing to fail as seen in the field.

wildem1

II-2 Unreinforced Bearing

Calculated By: MWW 09/02/2021

Bearing Pad

Use PCI handbook section 6..11.1 for bearing pad recommendations No manufacturer data available for bearing pad strength

Wpad 5in:= pad width

Bpad 5in:= pad length tpad 0.5in:= pad thickness

Shape Wpad Bpad×

2 Wpad Bpad+( )× tpad× 2.5=:= shape factor σallow 1000psi 100psi Shape×+ 1.25 103 ´ psi×=:= allowable bearing stress table 6.11.1.1

VAllow σallow Bpad× Wpad× 31.25 kip×=:= allowable bearing load

VASD 34.1kip:= ASD bearing load

VASD

VAllow

1.09=

Bearing capacity is exceeded by approximatly 10% however actual bearing loading is much higher due to bearings "walking" which causes concentrated loading.

wildem1

II-3 Bearing Pad wildem1

II-4 Original Calculations Original 12DT47 bearing calculations wildem1 Cloud wildem1

Insufficient rebar for Cr=1

Calculated By: MWW 09/02/2021

Shear Strength

Vu 43.6kip:= Bearing Load

Nu 0.2 Vu× 8.72 kip×=:= 0.2*Bearing Load (PCI Recommended) λ 0.75:= Lightweight concrete factor fc 5000psi:= Concrete strength fy 60ksi:=

Web Shear

Calculate web shear using ACI 318 22.5.8.3.2 Assume there is no prestressing force due to bearing failure bw 7in:= average stem width dp 37.6in:= depth to prestress fcp 0ksi:= prestress force

Vp 0:= vertical component prestress force

Vcw 3.5 λ× fc psi

× psi 0.3 fcp×+ æ ç è ö ø bw× dp× Vp+ 48.85 kip×=:= Eq. 22.5.8.3.2 ϕ 0.75:= Safety factor ϕ Vcw× 36.64 kip×= factored strength

Vu ϕ Vcw×

1.19=

Concrete does not have sufficient shear strength if prestress force is lost through concrete spalling however there is a welded wire mesh that provides addi onal shear strength.

wildem1 Text Box Part III Shear wildem1

III-1 Web Shear

Calculated By: MWW 09/02/2021

Check Shear Reinforcement drawings show end 12' have W4 welded wire spaced at 6" av 0.04in2 := welded wire area W4 welded wire spacing s 6in:=

Verify minimum reinforcement is provided avmin max 0.75 fc psi bw fy psi

× 50 bw fy psi æ ç ç è ö ø

6.19 10 3-in2 in ×=:= Eq. 9.6.3.3 av s

6.67 10 3-in2 in ×= Shear reinforcement area

Shear reinforcement meets code minimum.

shear depth d 47in:=

Eq. 22.5.10.5.3 Vs av fy× d× s

18.8 kip×=:= ϕVn ϕ Vcw Vs+( )× 50.74 kip×=:= Factored total shear strength

Vu ϕVn

0.86=

Total shear strength is sufficient. Bearing spalls will cause prestressing losses and weaken concrete shear strength…