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Aerodynamic Load Characteristics Evaluation and Multi-Axial Performance Testing on Fiber Reinforced Polymer Connections and Metal Fasteners to Promote Hurricane Damage Mitigation.

Aerodynamic Load Characteristics Evaluation and Multi-Axial Performance Testing on Fiber Reinforced Polymer Connections and Metal Fasteners to Promote Hurricane Damage Mitigation.

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  • Building structure integrity is compromised when the inter-component connections, such as roof-to-wall connections, wall-to-wall connections, wall-to-floor connections, or anchorage-to-foundations fail. Continuous load path and structural integrity are crucial for windstorm resiliency of residential buildings. Tropical cyclone damage has shown that wood structures tend to suffer little damage when the roof system remains intact under extreme wind loading, while major damage occurs when the roof system is partially or completely damaged (Reed et al. 1997). Post tropical cyclone inspections have noted the entire roofs detaching from buildings in some cases (Figure 2.5). This indicates a serious deficiency in the roof-to-wall connection systems, most notable in older construction. Thus the roof-to-wall connections play an important role to prevent roof failures and lessen the damages during high winds.
  • As wind impacts a building, it creates vortices that can overwhelm the structure on different locations (see Figure 2.1). As wind travels around sharp edges, such as wall corners, roof overhangs and roof ridgelines, a separation bubble is formed. The wind separation bubble is bounded by a free shear layer region of high velocity gradients and high turbulence (Holmes 2001). Conical vortices are formed (see Figure 2.2); as these are shed down wind, high negative pressure peaks are produced which generate suction or uplift loads on roofs up-lift loads on a roof are transferred through the roof elements (e.g., tiles, shingles) to the plywood sheathing to the roof trusses; which could lead to roof detachment if the inter-component connections are improperly designed or installed. Figure 2.3 illustrates the distribution of forces along a timber building during a high wind event. In a properly designed building the roof loads are transferred through a continuous vertical load path to the foundation.
  • The Florida Building Code (FBC, 2007) has special provisions for buildings in the High Velocity Hurricane Zone (HVHZ) which consists of Miami-Dade and Broward counties in the state of Florida. Due to the strict design and construction practices used in the HVHZ, all metal connectors must be approved and rated by the code compliance authorities for use in buildings. The Notice of Approval (NOA) lets structural designers know the capacity of a specific product to be used in their design (Figure 2.6). FBC-07: 2321.7.2 requires all wood to wood straps to resist a minimum uplift force of 700 pounds with 4-16d nails in each member (FBC, 2007). The nails used may change if the NOA allows it.
  • Compared to other configurations, Configuration A yielded more favorable results. The failure loads obtained with CFRP were 20% higher (Canbek, 2009). Nevertheless, the price of a CFRP tie connection is approximately 5 times higher than that of a GFRP tie connection. Therefore, Configuration A with GFRP was selected as the best alternative for further development (Canbek, 2009
  • 23 GFRP and 23 metal connector specimens were testedEach specimen was built using SPF No. 2 – 2 x 6 inch lumber with two separate connection systems, GFRP or metal connectors The test system was composed of a double acting 10,000 lbs hydraulic jack that could pull on the component specimen using a cable and pulley A load cell between the specimen and pulley recorded the ultimate failure load, via a DAQ computer Each specimen was bolted to an I-beam that in turn was attached to two channels bolted to the SCL tie-downs By moving the specimen North-South and East-West the resultant loading could be simulated

Canino defense nov 13 (f) Canino defense nov 13 (f) Presentation Transcript

  • Aerodynamic Load Characteristics Evaluation and Tri-Axial Performance Testing on Fiber Reinforced Polymer Connections and Metal Fasteners to Promote Hurricane Damage Mitigation
    Doctoral Dissertation Defense
    By
    Iván R. Canino
    Major Advisor: Dr. Arindam Gan Chowdhury
    November 13, 2009
    Civil & Environmental Engineering
    Florida International University
    Miami, Florida
  • Outline
    Background
    Structural Timber Roof-to-Wall Connection Deficiency
    Current Connection and Testing Methods
    Previous Development of Fiber Reinforced Polymer (FRP) Connection
    Development of FRP Connection using Component and Full-Scale Specimens
    Wall of Wind Testing
    Test Specimen
    Instrumentation
    Test Protocol
    Full-Scale Aerodynamic Load Characteristics for Roof-to-Wall Connections
    Full-Scale Test Results
    Discussion on Aerodynamic Characteristics
    Titan Structures and Construction Laboratory tri-Axial Testing
    New Tri-Axial Test Protocol
    Test Setup
    Results
    Conclusions
    Future Work & Recommendations
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Background
    HURRICANE
    HURRICANE DYNAMICS
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Background
    Comparison of Hurricane Losses (Dantin, 2006)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Background
    • Damages in Residential Buildings
    Reflect the obsolete and poor construction practices in tropical cyclone active areas.
    Wood-frame buildings account for approximately 90% of all residential buildings.
    Approximately 50% of the United States population now lives within 100 miles of a tropical cyclone-prone coastline.
    Building damage underscore the need for improving their structural performance; such as the weak-link at the roof-to-wall connection
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Background
    Wind Dynamics Around A Building
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Background
    Toe-Nailed Connection
    Hurricane Clip
    Past and Current Roof-to-Wall Connection Systems
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Background
    Miami Dade County Notice of Approval (NOA)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Background
    Up-Lift Tests
    Up-Lift Tests Close-Up
    Current Roof-to-Wall Connection Component Testing Methods (Simpson)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Background
    Parallel to the Wall (Top-Plate) L1
    Current Roof-to-Wall Connection Component Testing Methods (Simpson)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Background
    Perpendicular to the Wall (Top-Plate) L2
    Unidirectional Component Tests
    Up-lift
    Lateral to wall L1
    Perpendicular to wall
    Note: Current testing methods do not take into consideration the effects of simultaneous loading.
    Current Roof-to-Wall Connection Component Testing Methods (Simpson)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Background
    NIST Full Scale Up-Lift & Lateral Tests
    Current Roof-to-Wall Connection Full-Scale Testing Methods (NIST)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Background
    NAHB Lateral Tests
    NAHB Lateral Tests
    Current Roof-to-Wall Connection Full-Scale Testing Methods (NHAB)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Previous Development of FRP Connection
    Up-Lift Component Test Set-Up
    Sample Component Specimen
    FRP Roof-to-wall Connection Development (Canbek, 2009)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Previous Development of FRP Connection
    Carbon FRP (CFRP)
    Glass FRP (GFRP)
    FRP Test Specimens used in the Roof-to-wall Connection Development (Canbek, 2009)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Previous Development of FRP Connection
    Full-Scale Specimen
    Fink Trusses
    GFRP Tie Connection Full-Scale Uplift Specimen (Canbek, 2009)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Previous Development of FRP Connection
    FRP Results (Canbek, 2009)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Previous Development of FRP Connection
    Results of FRP Tie Connection Development (Canbek, 2009)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Previous Development of FRP Connection
    Cost Analysis for Configuration A with GFRP and CFRP (Canbek, 2009)
    NOTE: THE COST OF A CFRP TIE CONNECTION IS APPROXIMATELY 5
    TIMES HIGHER THAN THAT OF A GFRP TIE CONNECTION, SO
    GFRP WAS SELECTED FOR FURTHER DEVELOPMENT (CANBEK, 2009).
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind Testing -- Test Specimen
    WoW and Test Specimen, Ready for Testing at 90 Degrees
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Floor Membrane
    Wall with Door & Window
    Wall of Wind Testing -- Test Specimen
    WoW Test Specimen Construction
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Bottom Structure Assembly
    Bottom Structure Inside Wall Assembly
    Wall of Wind Testing -- Test Specimen
    WoW Test Specimen Construction
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Roof Trusses
    Assembly of Roof Trusses
    Wall of Wind Testing -- Test Specimen
    WoW Test Specimen Construction
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Mitered Top-Plate & GFRP Connection
    Typical 2 x 1.5 inch GFRP
    Wall of Wind Testing -- Test Specimen
    WoW Test Specimen Construction
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Bottom Structure and Truss Roof Assembly
    Test Specimen Assembly
    Wall of Wind Testing -- Test Specimen
    WoW Test Specimen Construction
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Eave Flashing
    Roof Flashing
    Wall of Wind Testing -- Test Specimen
    WoW Test Specimen Construction
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Soffit Connection Notched
    Soffit
    Wall of Wind Testing -- Test Specimen
    WoW Test Specimen Construction
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind Testing -- Instrumentation
    The test specimen was instrumented with the following sensors:
    6 Load Cellsunder the trusses; sandwiched between double top plate of walls and single top plate of roof . The recorded forces are FX, FY, and FZ corresponding to the in-plane shear (parallel to the side walls), out-of-plane shear (perpendicular to the side walls), and uplift, respectively.
    6 Linear Voltage Differential Transformers (LVDT)to measure horizontal displacements of GFRP truss connection (parallel to the side walls); placed on roof single top-plate.
    12 String Potentiometers (String Pots) to measure vertical deflection and horizontal deflection (perpendicular to the side walls) of the connections; placed on roof single top-plate.
    8 Strain Gaugesto measure strain in the vertical portion of each GFRP connection.
    2 Compact-Rios were used for all data acquisition, installed on the inside of the walls of the test specimen and controlled using a common laptop through an Ethernet connection.
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind Testing -- Instrumentation
    WoW Test Specimen Instrumentation and Connection Numbers
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind Testing -- Instrumentation
    Typical Connection Instruments
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Resurfaced Aluminum Plates
    Resurfaced Aluminum Plates ±0.01”
    Wall of Wind Testing -- Instrumentation
    WoW Test Specimen Instrumentation
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Load Cells Alignment
    Mounted Load Cells & Aluminum Plates
    Wall of Wind Testing -- Instrumentation
    WoW Test Specimen Instrumentation
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Load Cells & Aluminum Plates
    Mounted Load Cells & Aluminum Plates
    Wall of Wind Testing -- Instrumentation
    WoW Test Specimen Instrumentation
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Typical Connection Instrumentation
    Wall of Wind Testing -- Instrumentation
    String Pots & Stain Gauge
    WoW Test Specimen Instrumentation
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Pressure Transducers Between the Trusses
    Wall of Wind Testing -- Instrumentation
    Pressure Transducer on the Center of Test Specimen
    WoW Test Specimen Instrumentation
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind Testing -- Instrumentation
    Pressure Transducers #4 Between Middle & Rear Trusses
    Pressure Transducer Manifold
    WoW Test Specimen Instrumentation
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind Testing -- Instrumentation
    Compact Rios (Data Acquisition)
    WoW Test Specimen Instrumentation
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind Testing -- Protocol
    30 tests were performed
    5 angles of attack (AOA)
    Enclosed and partially-enclosed building conditions
    Wind without rain condition, and wind-driven rain (WDR) condition
    Each test was performed using a
    1 minute flat waveform (at maximum rpm of the WoW engines and generating high frequency turbulence only)
    3 minutes quasi-periodic waveform (generating low frequency turbulence in addition to high frequency turbulence).
    WoW Testing Protocol for GFRP Roof-to-Wall Connections
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • 0º AOA, Enclosed
    Wall of Wind Testing -- Protocol
    0º AOA, Enclosed &
    With Wind Driven Rain
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • 90º AOA, Partially Enclosed,
    One Window Removed
    45º AOA, Partially Enclosed, Two Windows Removed
    Wall of Wind Testing -- Protocol
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • WoW Phase I Test Protocol
    Wall of Wind Testing -- Protocol
    • 0 degree AOA with the gable ends being perpendicular to wind flow . A total of six tests were conducted.
    Enclosed building for 1 minute, at 4000 rpm.
    Enclosed building for 3 minutes, using a Quasi-Periodic waveform.
    Enclosed building with WDR for 1 minute, at 4000 rpm.
    Enclosed building with WDR for 3 minutes, using a Quasi-Periodic waveform.
    Partially-enclosed building (1 window and the door removed) for 1 minute, at 4000 rpm.
    Partially-enclosed building (1 window and the door removed) for 3 minutes, using a Quasi-Periodic waveform.
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind Testing -- Protocol
    WoW Phase II Test Protocol
    • 90 degree AOA with the gable ends being parallel to wind flow . A total of six tests were conducted.
    Enclosed building for 1 minute, at 4000 rpm.
    Enclosed building for 3 minutes, using a Quasi-Periodic waveform.
    Enclosed building with WDR for 1 minute, at 4000 rpm.
    Enclosed building with WDR for 3 minutes, using a Quasi-Periodic waveform.
    Partially-enclosed building (1 window removed) for 1 minute, at 4000 rpm.
    Partially-enclosed building (1 window removed) for 3 minutes, using a Quasi-Periodic waveform.
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind Testing -- Protocol
    WoW Phase III Test Protocol
    • 45 degree AOA with the gable ends being parallel to wind flow . A total of eight tests were conducted.
    Enclosed building for 1 minute, at 4000 rpm.
    Enclosed building for 3 minutes, using a Quasi-Periodic waveform.
    Enclosed building with WDR for 1 minute, at 4000 rpm.
    Enclosed building with WDR for 3 minutes, using a Quasi-Periodic waveform.
    Partially-enclosed building (2 windows removed) for 1 minute, at 4000 rpm.
    Partially-enclosed building (2 windows removed) for 3 minutes, using a Quasi-Periodic waveform.
    Partially-enclosed building (2 windows and the door removed) for 1 minute, at 4000 rpm.
    Partially-enclosed building (2 windows and the door removed) for 3 minutes, using a Quasi-Periodic waveform.
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind Testing -- Protocol
    WoW Phase IV Test Protocol
    • 30 degree AOA with the gable ends being parallel to wind flow . A total of four tests were conducted.
    Enclosed building for 1 minute, at 4000 rpm.
    Enclosed building for 3 minutes, using a Quasi-Periodic waveform.
    Partially-enclosed building (2 window removed) for 1 minute, at 4000 rpm.
    Partially-enclosed building (2 window removed) for 3 minutes, using a Quasi-Periodic waveform.
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind Testing -- Protocol
    WoW Phase V Test Protocol
    • 60 degree AOA with the gable ends being parallel to wind flow . A total of six tests were conducted.
    Enclosed building for 1 minute, at 4000 rpm.
    Enclosed building for 3 minutes, using a Quasi-Periodic waveform.
    Partially-enclosed building (2 windows removed) for 1 minute, at 4000 rpm.
    Partially-enclosed building (2 windows removed) for 3 minutes, using a Quasi-Periodic waveform.
    Partially-enclosed building (2 windows and the door removed) for 1 minute, at 4000 rpm.
    Partially-enclosed building (2 windows and the door removed) for 3 minutes, using a Quasi-Periodic waveform.
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind -- Testing AOA 0º, 4000 RPM, Enclosed & With Water
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Wall of Wind -- Testing AOA 45º, Quasi-Periodic RPM, Enclosed & With Water
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Full-Scale Aerodynamic Load Characteristics for Connections
    WoW Test Results for GFRP Roof-to-Wall Connections
    WoW test results are represented as:
    Graphs of the 3-second time averaged histories of individual load cells
    Bar graphs with mean results of all the conditions per load cell
    Scatter plots with mean force results of individual load cells
    Graphs of the 3-second time averaged histories of strain in connections
    Graphs of the 3-second time averaged histories for LVDTs (Displacements parallel to side walls in connections)
    Graphs of the 3-second time averaged histories for String Pots (Displacements perpendicular to side walls in connections)
    Graphs of the 3-second time averaged histories for String Pots (Vertical displacements in connections)
    Graphs of the 3-second time averaged histories of Internal Pressures
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Full-Scale Aerodynamic Load Characteristics for Connections
    WoW Test Results for GFRP Roof-to-Wall Connections
    The nomenclature used to determine the type of test runs in the graphs is as follows:
    E_FT: enclosed condition and wind speeds at full-throttle
    E(W)_FT: enclosed condition with wind driven rain and at full-throttle
    PE_FT: partially enclosed condition where 1 (for AOA 90º test) or 2 (for AOA 45º test) windows have been removed and 1 window and the door (for AOA 0º test) and at full-throttle
    PE’_FT: partially enclosed condition, where the windows and the test specimen door have been removed at full-throttle (for AOA 45º & 60º tests)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Full-Scale Aerodynamic Load Characteristics for Connections
    WoW Test Results for GFRP Roof-to-Wall Connections
    The nomenclature used to determine the type of test runs in the graphs is as follows:
    E_QP : enclosed condition and a quasi-periodic ramp function
    E (W)_QP : enclosed condition with wind driven rain and quasi-periodic ramp function
    PE_QP: corresponds to a partially enclosed condition where 1 (for AOA 0º & 90º tests) or 2 (for AOA 45º test) windows have been removed and a quasi-periodic ramp function
    PE’_QP: corresponds to a partially enclosed condition where 2 (for AOA 45º & 60º tests) windows and the test specimen door have been removed and a quasi-periodic ramp function
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • WoW Full-Scale Test Results Time Histories of Fz -- LC #1 -- AOA 0º
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • WoW Full-Scale Test Results Time Histories of Fz -- LC #1

    30º
    30º
    90º
    60º
    45º
  • WoW Full-Scale Test Results Time Histories of Fz -- LC #2

    30º
    90º
    60º
    45º
  • WoW Full-Scale Test Results Time Histories of Fz -- LC #3

    30º
    90º
    60º
    45º
  • WoW Full-Scale Test Results Time Histories of Fz -- LC #4

    30º
    90º
    45º
    60º
  • WoW Full-Scale Test Results Time Histories of Fz -- LC #5

    30º
    90º
    45º
    60º
  • WoW Full-Scale Test Results Time Histories of Fz -- LC #6

    30º
    90º
    60º
    45º
  • WoW Full-Scale Test Results
    LC #1 -- Bar Graph of Mean Fx at 4400 RPM
    for all Conditions & AOAs
  • BAR GRAPHS ALL CONDITIONS & AOAs: Mean FX (4000 RPM)
    LC 1
    LC 4
    LC 2
    LC 5
    LC 3
    LC 6
  • BAR GRAPHS ALL CONDITIONS & AOAs: Mean Fy (4000 RPM)
    LC 1
    LC 4
    LC 2
    LC 5
    LC 3
    LC 6
  • BAR GRAPHS ALL CONDITIONS & AOAs: Mean Fz (4000 RPM)
    LC 1
    LC 4
    LC 2
    LC 5
    LC 3
    LC 6
  • WoW Full-Scale Test Results
    LC #5 – Scatter Plot of Mean Fx, Fy & Fz
    at 4000 RPM (Enclosed and all AOAs)
  • Scatter Plots of Mean Forces Fx, Fy & Fz(Enclosed, 4000 RPM)
    LC 1
    LC 4
    LC 2
    LC 5
    LC 3
    LC 6
  • Scatter Plots of Mean Forces Fx, Fy & Fz(Enclosed, with Water, 4000 RPM)
    LC 1
    LC 4
    LC 2
    LC 5
    LC 3
    LC 6
  • Scatter Plots of Mean Forces Fx, Fy & Fz(Partially Enclosed, 4000 RPM)
    LC 1
    LC 4
    LC 2
    LC 5
    LC 3
    LC 6
  • Scatter Plots of Mean Forces Fx, Fy & Fz(Partially Enclosed’, 4000 RPM)
    LC 1
    LC 4
    LC 2
    LC 5
    LC 3
    LC 6
  • WoW Full-Scale Test Results
    LC #5 - Time Histories of Strain -- AOA 60º,
    All Conditions
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • WoW Full-Scale Test Results Time Histories of Strain at All AOAs -- LC #5

    30º
    90º
    60º
    45º
  • WoW Full-Scale Test Results
    LC #5 - Time Histories of Displacements Parallel to Side Walls (LVDT measurements) – AOA 0º, All Conditions
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • WoW Full-Scale Test Results Time Histories of Displacements Parallel to Side Walls (LVDT measurements) -- LC #5

    30º
    90º
    45º
    60º
  • WoW Full-Scale Test Results
    LC #1 - Time Histories of Displacements Perpendicular to Side Walls (String Pots measurements) – AOA 0º, All Conditions
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • WoW Full-Scale Test Results Time Histories of Displacements Perpendicular to Side Walls (String Pots measurements) -- LC #1

    30º
    90º
    60º
    45º
  • WoW Full-Scale Test Results
    LC #1 - Time History of Vertical Displacements (String Pots measurements) – AOA 0º, All Conditions
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • WoW Full-Scale Test Results Time History of Vertical Displacements (String Pots measurements) -- LC #1

    30º
    90º
    60º
    45º
  • Full-Scale Aerodynamic Load Characteristics for Connections
    Effect of Internal Pressure due to Breach of Envelope
    Time History of Highest Recorded Loads in Connection #5; Partially Enclosed, 0º AOA
    Partially Enclosed, 0º AOA
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • WoW Full-Scale Test Results LC #5 – Load Difference Between an Enclosed and Partially-Enclosed Conditions – AOA 0º
    Connection #5 Up-Lift Time Histories for Enclosed & Partially Enclosed Conditions
    Connection #5 Mean Up-Lift Forces for Enclosed & Partially Enclosed Conditions
    The maximum difference, related to the uplift loading between
    enclosed and partially-enclosed conditions was recorded to be 528 lbs
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • WoW Full-Scale Test Results Time Histories and Mean Internal Pressure (Transducers #3, 4 & 5) -- Near Connection 5
    Transducer#3
    Transducers# 3, 4 & 5 (E & PE at FT)
    Transducer#4
    Mean Internal Pressures: Transducers #3, 4, & 5 (E&PE@FT)
    Transducer#5
  • Discussion on Aerodynamic Characteristics
    Effect of Internal Pressure Increase on Uplift Loading
    Connection #5, 117 lbs and 645 lbs for E and PE conditions, respectively -- the difference being 528 lbs
    Mean internal pressures difference was 0.08 psi
    The tributary area 35 sq. ft. - load of about 400 lbs
    The measured uplift increment on the connection is higher than the estimated value (both showed significant increase)
    The difference could be due to approximation of tributary area and spatial correlation of internal pressure
    The experiments indicate how severe can be the effects of breach of building envelope (5.5 times of uplift load increase)
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Discussion on Aerodynamic Characteristics
    Effect of Turbulence (Low Frequency Vs High Frequency)
    The proportionalities between the mean uplift, in-plane, and out-of-plane forces are very similar for flat and quasi-periodic waveforms
    Higher turbulence (TI 24% vs 5%) generated by the low frequency fluctuations of the wind does not affect the proportionalities between the mean uplift and lateral forces induced on the connections
    Thus rigorous generation of turbulence intensity and integral length scale (as always attempted in wind tunnels) may not be necessary for tri-axial loading evaluation for roof-to-wall connections
    For further testing of the GFRP connections to failure under tri-axial loading in SCL, only the data obtained for the flat waveform tests are used
    FLORIDA INTERNATIONAL UNIVERSITY - CIVIL & ENVIRONMENTAL ENGINEERING
  • Discussion on Aerodynamic Characteristics
    Effect of Wind Driven Rain
    Hurricane winds are accompanied by wind-driven rain
    Generally wind tunnels cannot be used for comprehensive research into this phenomenon
    WoW was used to determine if there is any significant difference between aerodynamic and aero-hydrodynamic loading induced on the GFRP connections
    No significant increase in load was observed during the wind-driven rain tests as compared to wind with no rain
    The data used for failure testing in SCL were obtained from the wind tests
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  • Discussion on Aerodynamic Characteristics
    Database for Tri-Axial Loading on Connections
    Load cells measured uplift, in-plane (parallel to the side walls), and out-of-plane (perpendicular to the side walls) loads experienced by each GFRP connection
    The results were used for tri-axial loading of the GFRP connection in SCL till failure at the component level
    For each test the three force components were converted to a resultant mean load in order to test the GFRP connections more realistically using aerodynamic loading obtained from WoW tests
    A total of 36 resultant forces were obtained from the loads recorded at the WoW and were used to test the newly developed GFRP connections and metal hurricane clips
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  • Titan Structures and Construction Laboratory Tri-Axial Testing
    • Rationale for Tri-Axial Testing of Connections
    • Under real storms a fastener will experience simultaneous uplift, in-plane, and out-of-plane loading which will have specific ratios based on several factors (e.g., location of the connection, type of the roof, etc)
    • The common practice of Uni-Axial testing can lead to incorrect specifications of the allowable capacity of a mechanical fastener
    • To circumvent the above limitations the new testing approach is based on simultaneous aerodynamic tri-axes loads with proportionalities obtained from realistic full-scale WoW testing
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  • Titan Structures and Construction Laboratory Tri-Axial Testing
    • New Tri-Axial Testing Protocol and Test Setup
    • New tri-axial test protocol was established and connections tested to failure at the SCL using ratios of uplift to in-plane lateral and out-of-plane lateral loads
    • Each test in SCL represented a particular tri-axial aerodynamic loading obtained at the WoW for specific parameters: connection location, angle of attack, and internal pressure condition (enclosed or partially enclosed condition) -- results were compared with those from testing using individual loading
    • Series of resultant mean forces were used to test the GFRP component connections in the SCL up to failure -- 23 of the 36 resultant forces were used due to limitations in the SCL system
    • Hurricane clips were tested to provide a comparison of performance between GFRP and metal connections subjected to simultaneous tri-axial loading
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  • Titan Structures and Construction Laboratory Tri-Axial Testing
    • New Tri-Axial Testing Protocol and Test Setup
    The locations were determined using ratios of the two lateral forces divided by the up-lift force (i.e. FX/FZ and FY/FZ)
    The vertical component of the 3-D coordinate system was constant
    Moving the I-beam further away from the jack and pulley simulated the FY -component
    Moving the specimens on the I-beam from East to West simulated the FX – component
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  • Tri-Axial Component Testing --Test Set-Up
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  • Tri-Axial Component Testing --Test Set-Up Locations
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  • Tri-Axial Component Testing --Results AOA 0º
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  • Tri-Axial Component Testing –Results AOA 30º
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  • Tri-Axial Component Testing --Results AOA 45º
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  • Tri-Axial Component Testing --Results AOA 60º
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  • Tri-Axial Component Testing --Results AOA 90º
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  • Tri-Axial Component Testing – GFRP Tests
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  • Tri-Axial Component Testing – Clip Tests
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  • Tri-Axial Component SpecimensFailure Modes Case 2
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  • Tri-Axial Component Specimens FailureModes Case 6
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  • Tri-Axial Component Specimens Failure Modes Case 11
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  • Tri-Axial Component Specimens Failure Modes Case 15
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  • Tri-Axial Component Specimens Failure Modes Case 23
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  • Conclusions
    Feasibility of GFRP Connections as Substitute to Metal Connections
    The failure load capacity of the GFRP connection performed similar to and in most cases better than the metal fasteners test results (under tri-directional simultaneous loads obtained from aerodynamic tests at the WoW)
    In some cases the ultimate failure resultant load for the GFRP connection was observed to be double of that for the metal fastener
    The GFRP connection test results seem to demonstrate that it can be applicable to new construction as well as retrofitting of old residential buildings that require strengthening against extreme wind loads with minimally intrusive techniques.
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  • Conclusions
    Failure Modes of GFRP Connections Vs Metal Connections
    The results show that the failure modes of connection joints are highly dependent on the type of the connection (GFRP versus metal)
    It was noted that as GFRP is non-intrusive it doesn’t weaken the wood members and crushing of wood is avoided (Ahmed et al., 2009). The failure mode observed was mostly detachment of GFRP from the wood surface and wood surface peeling
    In the case of the hurricane clip the failure mode was observed as both nail withdraw or pull-out, clip rupture
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  • Conclusions
    Differences in Test Results -- Uni-Axial Vs Tri-Axial Testing
    The failure loads for both connectors (GFRP and metal) decreased during the tri-axial test
    When the coefficients FX/FZ and FY/FZ for the tri-axial testing were low the uplift capacity matched the uni-axial testing uplift capacity closely
    However when the coefficients were high, reduced uplift capacity was observed compared to the uni-axial testing uplift capacity
    This indicated that the lateral load components, if applied simultaneously with the uplift load component as experienced during real storms, the uplift load capacity of the connection is reduced – so that the uni-axial uplift test results are overestimated
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  • Conclusions
    In one of the most extreme the uplift failure recorded loads were 295 (884/3FS) pounds and 250 (750/3FS) pounds as compared to the 720 pounds and 437 pounds , obtained from uni-axial testing, for the GFRP and metal clip, respectively
    The lateral (parallel to the walls) failure loads were 102 (307/3FS) pounds and 87 (260/3FS) pounds as compared to the 552 pounds and 165 pounds obtained from uni-axial testing for the GFRP and metal clip, respectively
    Results indicate the inappropriateness of the existing uni-axial testing protocol used to test connectors
    Design based on these erroneous allowable load capacities can cause inter-component connection failures during high wind events
    Improving upon current practice by taking into account the results (WoW database) reported herein and the suggested tri-axial testing will improve the performance of timber construction in high winds
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  • Conclusions Project Contributions
    Based on WoW testing a database (may be used by other researchers and industry professionals) has been developed on aerodynamic and aero-hydrodynamic loading on roof-to-wall connections tested under several parameters: angles of attack, wind-turbulence content, enclosed and partially-enclosed building conditions, with and without effects of rain
    The research’s findings demonstrated that a GFRP connection system is a viable option for use in a timber roof-to-wall connection system
    A component level testing protocol and setup have been developed in SCL to test connections to failure under the influence of simultaneous tri-axial loading; such protocol eliminates the erroneous load capacity predictions from existing uni-axial test protocols
    A database has been developed on the uni-axial and tri-axial load capacity of the GFRP connections and of a particular type of metal fastener; simultaneous application of tri-axial loading to roof-to-wall connections in SCL is one of the first attempts to mimic realistic aerodynamic loads obtained from full-scale wind testing
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  • Future Work Recommendations
    The GFRP connection has yet to be tested aerodynamically under Category 4 and 5 hurricane conditions; this can be simulated in the 12-fan WoW system which is presently under development
    A series of timber structures, within tropical cyclone prone coastal areas, could be retrofitted with the new GFRP roof-to-wall connections. Building performance under possible future storms can then provide validation of the connections -- there is no better test method than subjecting the connections to actual tropical cyclone conditions
    Such retrofitting can also be used to study the long term weather effects of moisture, heat and rain on the GFRP connections, which are not yet completely understood
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  • Future Work Recommendations
    Studies on creep and fatigue are warranted for the GFRP connections
    The tri-axial testing method and system used in this research could be improved to test all 36 resultant aerodynamic forces obtained from the WoW tests; this could be done by enhancing the current testing system by enlarging the size of the system and implementing a pulley swivel system that can allow more lateral locations to be tested
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  • END OF PRESENTATIONTHANK YOU FOR YOUR TIMEANY QUESTIONS?
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