Experimental and Numerical Study to Improve Damage and Loss Estimation due to Overland Wave and Surge Hazards on Near-Coast Structures

Transcription

1 CRC 2 nd Annual Meeting: February 1 3, 2017, Chapel Hill, NC Experimental and Numerical Study to Improve Damage and Loss Estimation due to Overland Wave and Surge Hazards on Near-Coast Structures Daniel Cox Oregon State University John van de Lindt Colorado State University Kevin Cueto, Diego Delgado, Trung Do, Ben Hunter, Tori Johnson, Hyoungsu Park, Willliam Short

2 Introduction Objective 1: Quantify surge/wave forces on near-coast structures and develop new predictive equations. Objective 2: Develop the conditional probabilities (fragilities) for exceeding key thresholds. Objective 3: Illustrate next-generation riskinformed design. Project Overview

3 Introduction Existing FEMA Damage Predictions Predicted Damage: 72% Predicted Damage 60% Case 1: Freeboard=-2.7 m Damage: Interior water damage, minimal structural damage Significant Wave Height: 0.99m Case 2: Freeboard=-1.5 m Damage: 100% Significant Wave Height: 1.37 m

4 Introduction Technical Approach Task 1: Hydraulic model test program at OSU (Yr 1) and data analysis (Yr 1, 2). Task 2: Numerical model program at CSU. Verification (Yr 1) and fragility development (Yr 1, 2). Task 3: Develop performance based design examples to illustrate methodology for engineering practice (Yr 2).

5 Research Accomplishments Task 1: Hydraulic model test program Hurricane Ike 2008 / Bolivar Peninsula, TX Observed surge and wave action: Offshore significant wave height: 5.8 m Storm surge: 4.3 m Inundation: m Estimated overland waves: 1.9 m

6 Research Accomplishments First comprehensive measurements of wave forces on elevated residential structures Simplifying Assumptions No substructure No sediments, scour No debris No currents Geometric scale 1:10 Wave height: 0.10 < H < 0.50 m Inundation: 0.40 m Specimen dimensions: 1.02 x 1.02 x 0.61 m Froude similitude 1:3.16 Wave period: 2.5 < T < 5.0 s The University of North Carolina at at Chapel Hill Hill

7 Research Accomplishments Gulf of Mexico Barrier island Bay

8 Research Accomplishments Gulf of Mexico Barrier island Bay

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12 Research Accomplishments Exp. TMA REG TRAN H S (m) T P (s) h (m) Dur. (min) H" (m) T$ (s) h (m) Dur. (min) A (m) T R (s) h (m) t s (s) X X X X X X X X X X Data are hosted on NSF DesignSafe-CI for public access

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14 Research Accomplishments Air Gap cases REG TMA a (m) TRAN a a a a a a a a a a SWL a

15 Effects of Air Gap on Horizontal, Vertical Forces - Horizontal force increases as air gap decreases. Research Horizontal Accomplishments Force - The maximum vertical force is found when the air gap is zero. - In some cases vertical force can exceed horizontal force Vertical Force - There are limited provision in FEMA 55 or ASCE 7-16 to estimate these forces 15

16 Education and Outreach Participation in SUMREX program Kevin Cueto; Diego Delgado7-week summer program at HWRL Contributed to October 2016 feature article on CRC page Thank you, Josh!

17 Research Accomplishments Task 2: Numerical model program at CSU. Verification (Yr 1) and fragility development (Yr 1, 2). Model verification using existing data - Tsunami loads on wood-frame wall at full scale test by Linton et al. (2013) - Uplift forces on a large scale bridge superstructure by Bradner et al. (2011) - Elevated Structure Impact test at OSU (2016)

18 3.66 m Flume wall Flume botom Calibrating model using wood-frame wall at full scale test Research Accomplishments 0.33 m 2.36 m Location 3 Displacement (Location 3) Load cells (Supports) a) b) 0.33 m m m 3.58 m m Wave maker Location 1 Tsunami wave Location 2 Wood wall 3.58 m 2.44 m 2.44 m 2.44 m 1.85 m 1.85 m 2.44 m 1.85 m m m Flume Flume wall wall Flume botom Sketch of transverse wood wall in flume Wave maker Location m 2.36 m 2.36 m Tsunami wave Location 3 Displacement (Location 3) Load cells (Supports) a) b) Numerical model of Wood wall wood wall Location m 0.33 m 2.44 m v 1 = v (z,t) 2.36 m 3.66 m 2.36 m 7.0 m 1:12 2.5m 25.4 m side face, v 2 =0 flow-in face, v 1 =v(z,t) sea water material c) d) 35.7 m bottom face: v 3 =0 3.6 m 7.3m 0.5m 3.66 m Empty material Numerical of wave flume and wood wall Location 3 top face p=0 flow-out face, p=0 1= v (z,t) 3.66 m Location 3

19 Research Accomplishments Comparing numerical results and tested data Compare deep water wave height at location 1 (a), running up wave height(b) and velocity (c) In front of the wall (location 2) Compare flux (d), total horizontal force (e) at location 2, and deflection at mid span of the wall (location 3)

20 Research Accomplishments Model verification with uplift loads Compare result for total uplift on bridge between model and test Analysis of failure mechanics: total uplift exceed the self-weight of bridge superstructure causing failure

21 Research Accomplishments Elevated Structure Impact test at OSU (2016) Locations of pressure gauges Numerical model of flume and elevated structure in wave flume Locations of wave gauges

22 Research Accomplishments Video showing wave impact on elevated structure

23 Research Accomplishments Comparing wave heights at wage gausses

24 Research Accomplishments Comparing results at pressure gauges

25 Research Accomplishments Task 2: Numerical model program at CSU. Verification (Yr 1) and fragility development (Yr 1, 2). Fragility development 3 Building archetypes are selected from 6 residential wood building archetypes of the hurricane wind project Set up numerical model and collect total uplift and shear as well as force on components such as doors, windows, and walls Establish damage states based on damage of components such as door, windows, and nails connection of wood walls. Generate fragility surfaces based on both significant wave heights and flood levels Archetype 1 23 x 50 ft (7x15m), Rectangle, 1-story Archetype 2 38 x 52 ft (12x16m), 2-story Archetype 3 38 x 65 ft (12x20m), 2-story

26 Research Accomplishments Building models The buildings are modeled in ANSYS Fluent Piles rising from 0, 1m, 2m, and 3m, from the ground TMA spectrum for hurricane waves with H " = 1, 2, and 3 m, which can cover up to 12m significant wave height in deep water, and wave peak period, T $, from 8s to 14s Surge (SWL, food) levels h = 1, 2, and 3m Archetype 1 With 3-m elevated pile from ground

27 Research Accomplishments Example of wave impact on building archetype 1 Piles rising 1m from the ground Significant wave height = 1m Flood level = 1m

28 Research Accomplishments Pressure measured location and distribution at one wave impact event PG7 PG6 PG5 PG4 PG3 PG2 PG1 PG7 PG5 PG3

29 Research Accomplishments Table of combinations for each building archetype Pile Elevation (m) Surge level (Hs, m) Significant wave height (m) Pile Elevation (m) Surge level (Hs, m) Significant wave height (m) Archetype Archetype

30 Research Accomplishments Define of fragility curve for coastal structures A fragility, F ', can be expressed as F ' (x) = P[Q > R x] For elevated structures subjectedto storm surge: -Q = loading from the model for every combination of (H ", T $ )and/or surge levels, S -R= Resistant/ capacity -Hazardintensities, x = Significant wave height (H ", T $ ), Surge levels, S. For different time duration P 5 in X hours = 1 1 P 5 in Y hours A B Damage State Window/ door failure Wall failure 0 (no damage) <1% No No 1 (Minor damage) >1% and <5% 2 (Moderate) >5% and <25% 3 (Severe damage) >25% and <50% No Floor failure No >5% and <25% >5% and <25% >25% and <50% >25% and <50% 4 (Destruction) >50% >50% >50%

31 Research Accomplishments Component Resistance Values Used to Model Residential Buildings (Hazus 2.1- Hurricane) Component Distribution Parameters Window on 1 story Window on 2 story Weibull C = 54.49psf, k = 4.7 Weibull C = 38.7psf, k = 4.8 Entry door Normal Mean=50psf, COV=0.2 Toe-nail Normal Mean=415lb, COV=0.25

32 Research Accomplishments Fragilities surfaces for building subjected to wave and surge Probability of failure base on two environmental variables given some damage states -Significant wave height -Surge/flood level Example: when significant wave height = 2.0m, surge level = 2.5m => Probability of failure due to Damage State 1 = 19% when building was raised 1 m from the ground

33 Applications Task 3: Develop performance based design examples to illustrate methodology for engineering practice (Yr 2). Application to Galveston, TX Crystal Beach, TX Damage to residential housing Crystal Beach, TX Hurricane Ike (2008)

34 Current Flood Maps for Crystal Beach Online Mapping Tool: similar elevations Applications

35 Applications Date of Construction Study area: 394 houses. Use appropriate FIRM and distance from shore to estimate house elevation

36 Approximate elevation, LCM Applications

37 Applications Overlay building stock with hazard: Hs max, from ADCIRC simulations by Bret Webb, U. South Alabama. via NIST project Houses are colored by the age classification. Fragility curve selection in Tomiczek et al.

38 Applications

39 Results: Likelihood of Failure (Collapse Limit State) Applications

40 Results: Likelihood of Failure (Collapse Limit State) Applications

41 Applications Likelihood of Failure (Collapse Limit State) Increase elevation of all structures by 1 m Potential for decision support tool

42 End User Engagement Revisions to FEMA 55 Coastal Construction Manual and ASCE 7-16 Workshop July 19+20, 2017 at OSU to develop research roadmap and implementation plan FEMA-55 CCM committee lead Chris Jones, Chair of ASCE 7 Flood Load Subcommittee Gary Chock, Chair of ASCE 7 Tsunami Subcommittee We plan to work with the following people involved in the End-User Transition: HAZUS Program Manager at FEMA HQ FEMA Building Science Division Chad Berginnis, ASFPM Executive Director and CRC Advisory Board Member USACE Institute for Water Resources Coastal Engineer, FEMA Risk Analysis Branch, Atlanta GA

43 Proposed Follow-on Work Hazard Data (ADCIRC/SWAN) Tracking modeling uncertainties Fragility Functions Expected Damage 1. Building Data 2. Energy/EPN 3. Water 4. Transportation 5. Communication Kennedy et al., October 2016

44 Proposed Follow-on Work Comparison of new physics-based fragilities to empirical and Hazusfragilities Application to NJ coast (post-sandy)

45 Proposed Follow-on Work Mitigation measures for existing and new construction: Examples of mitigation measures to increase building performance for wind (a d) from FEMA s Coastal Construction Manual. (e) Example of testing elevated bridge at HWRL.

46 Proposed Follow-on Work Debris Impact: (a) Flood-borne debris hazards (FEMA 2000), (b) log-structure impact at 1:1 scale and (c) shipping container-column impact at 1:25 scale.

47 Proposed Follow-on Work Prototype-scale testing for breakaway walls: (a) New construction of elevated home with breakaway wall on first floor. (b) Example of prototype-scale testing at HWRL of wave loads on subassembly and (c) structural failure.

48 Thank you Daniel Cox John van de Lindt, Kevin Cueto, Diego Delgado, Trung Do, Ben Hunter, Tori Johnson, Pedro Lomonaco, Hyoungsu Park, William Short