Loads, Load Factors and Load Combinations
Overall Outline
1000. Introduction 4000. Federal Regulations, Guides, and Reports Training Course on 3000. Site Investigation Civil/Structural Codes and Inspection 4000. Loads, Load Factors, and Load Combinations 5000. Concrete Structures and Construction 6000. Steel Structures and Construction 7000. General Construction Methods BMA Engineering, Inc. 8000. Exams and Course Evaluation 9000. References and Sources
BMA Engineering, Inc. – 4000 1 BMA Engineering, Inc. – 4000 2
4000. Loads, Load Factors, and Load Scope: Primary Documents Covered Combinations
• Objective and Scope • Minimum Design Loads for Buildings and – Introduce loads, load factors, and load Other Structures [ASCE Standard 7‐05] combinations for nuclear‐related civil & structural •Seismic Analysis of Safety‐Related Nuclear design and construction Structures and Commentary [ASCE – Present and discuss Standard 4‐98] • Types of loads and their computational principles • Load factors •Design Loads on Structures During • Load combinations Construction [ASCE Standard 37‐02] • Focus on seismic loads • Computer aided analysis and design (brief)
BMA Engineering, Inc. – 4000 3 BMA Engineering, Inc. – 4000 4 Load Types (ASCE 7‐05) Load Types (ASCE 7‐05)
• D = dead load • Lr = roof live load
• Di = weight of ice • R = rain load • E = earthquake load • S = snow load • F = load due to fluids with well‐defined pressures and • T = self‐straining force maximum heights • W = wind load • F = flood load a • Wi = wind‐on‐ice loads • H = lldoad due to lllateral earth pressure, ground water pressure, or pressure of bulk materials • L = live load
BMA Engineering, Inc. – 4000 5 BMA Engineering, Inc. – 4000 6
Dead Loads, Soil Loads, and Dead Loads HdHydros ttitatic Pressure • Dead loads consist of the weight of all materials of construction incorporated into the building, e.g., – Walls, floors, roofs, ceilings, stairways, built‐in partitions, finishes, cladding, and other fixed service equipment including weight of cranes • Unit weight of materials and dimensions of components • Soil loads, lateral pressure, hydrostatic loads, and uplift
BMA Engineering, Inc. – 4000 7 BMA Engineering, Inc. – 4000 8 Live Loads Dead or Live Loads • A load produced by the use and occupancy of the • Tributary area and live load reduction bldbuilding or other structure that does not inclldude construction or environmental loads, such as wind ldload, snow lldoad, rain ldload, earthkhquake lldoad, floo d load, or dead load • Tabulated unit loads by occupancy and use of a structure
BMA Engineering, Inc. – 4000 9 BMA Engineering, Inc. – 4000 10
Flood Loads Wind Loads • They apply to structures located in areas prone to • Structures shall be designed and constructed to flooding, and include resist wind loads computed based in specified wind – Hydrostatic loads speed and various wind & pressure coefficients: – HdHydro dynam ic lldoads (i)(moving) – Simp lifie d procedure for commonly used bu ilding – Wave loads (repeated impact) geometries, closures, and stiffness without torsion • Structures shall be designed, constructed, – Analytical procedure for regular‐shaped without special wind‐related effects including torsion connected, and anchored to resist flotation, collapse, – Wind tunnel procedure is permitted in lieu of the above and permanent lateral displacement due to action of two methods for any building or structure flood loads associated with the design flood and other loads in accordance with load combinations • The effects of erosion and scour shall be included in the calculation of loads
BMA Engineering, Inc. – 4000 11 BMA Engineering, Inc. – 4000 12 Wind Loads: Wind Speed Wind Loads: Wind Speed
Importance Factors: Degree of hazard to human life and damage to property
BMA Engineering, Inc. – 4000 13 BMA Engineering, Inc. – 4000 14
Method 1: Simplified Procedure Method 2: Analytical Procedure
BMA Engineering, Inc. – 4000 15 BMA Engineering, Inc. – 4000 16 Method 2: Analytical Procedure Method 2: Analytical Procedure
BMA Engineering, Inc. – 4000 17 BMA Engineering, Inc. – 4000 18
Method 2: Method 3: Wind Tunnel Analytical Procedure
Main wind force resisting system
Burj Dubai
BMA Engineering, Inc. – 4000 19 BMA Engineering, Inc. – 4000 20 Wind Load Effects Wind Load Effects Tacoma Narrow Bridge – See also video file: Tacoma Bridge
BMA Engineering, Inc. – 4000 21 BMA Engineering, Inc. – 4000 22
Snow Loads Ground Snow load for flat roof (f) (<5%) Snow Loads
p f 0.7CeCt Ipg
pg = ground snow load (tabulated) Exposure and thermal factors
BMA Engineering, Inc. – 4000 23 BMA Engineering, Inc. – 4000 24 Snow Loads Rain Loads • Rain load on the undeflected roof, i.e., rain loads computed without any deflection from loads (including dead loads) • Loads bdbased on roof drainage systems • Ponding instability, where “Ponding” refers to the retention of water due solely to the deflection of relatively flat roofs
BMA Engineering, Inc. – 4000 25 BMA Engineering, Inc. – 4000 26
Ice Loads Ice Loads • Atmospheric ice loads due to freezing rain, snow, and in‐cloud icing shall be considered in the design of ice‐ sensitive structures • 50‐year mean recurrence interval uniform ice thickness due to freezing rain (next slide)
BMA Engineering, Inc. – 4000 27 BMA Engineering, Inc. – 4000 28 Seismic Analysis (ASCE 4‐98) Seismic Analysis (ASCE 4‐98) TOKYO ELECTRIC POWER COMPANY Earthquakes, • The Niigata-ken Chuetsu-oki FltPltFaults, Plate Earthquake (NCOE) occurred in 2007 Tectonics, • The Kashiwazaki Kariwa Nuclear EthEarth Struct ure Power SttiStation l oca tdithted in the same area • The station was hit by a big tremor more than its intensity assumed to be valid at the station design stage • Preventive functions for the station safety worked as expected as it designed • Critical facilities designed as high seismic class were not damaged , though considerable damages were See video: 10.5‐ Earthquake in San Francisco! See video 10.5‐ M7.0 Earthquake Simulation seen in outside-facilities designed for Hayward Fault, California as low seismic class See video 10.5‐ Earthquake Destruction
BMA Engineering, Inc. – 4000 29 BMA Engineering, Inc. – 4000 30
Seismic Analysis (ASCE 4‐98) Seismic Analysis (ASCE 4‐98) In case of a release, prevailing wind predicted fallout pattern
BMA Engineering, Inc. – 4000 31 BMA Engineering, Inc. – 4000 32 25 Seismic Analysis (ASCE 4‐98) 20 • Requirements for performing analyses on 15 Earthquake load structures under earthquake motion 10 • Provide rules and analysis parameters that 5 pr oduce seis mic respon ses with sam e 0 probability of non‐exeedance as the input • Specifications of input motions -5 • Analysis standards for modeling of structures -10 • Soil structure interaction modeling and -15 analysis -20 • Input for subsystem seismic analysis -25 • Special structures 0 123 4 5 6 7 8 910 TIME - seconds • Seismic probabilistic risk assessment and seismic margin assessments Base dildisplacemen t Typical Earthquake Ground Acceleration - Percent of Gravity BMA Engineering, Inc. – 4000 33 BMA Engineering, Inc. – 4000 34
2 20 0 18 16 - 2 14
- 4 12 10 - 6 8 1.0 Percent Damping 6 5.0 Percent Damping - 8 4 - 10 2 0 - 12 012345 012345678910 PERIOD - Seconds TIME - seconds Relative Displacement Spectrum y (T) Inches Absolute Earthquake Ground Displacements - Inches MAX
BMA Engineering, Inc. – 4000 35 BMA Engineering, Inc. – 4000 36 100 90 Seismic Analysis (ASCE 4‐98) 80 • Steps in design and construction process that 70 101.0 Percen t Damp ing 5.0 Percent Damping ldlead to the relblliability of nuclear safety‐reldlated 60 structures under earthquake motion 50 – Definition of seismic environment 40 – Analysis to obtain seismic response information 30 20 – Design or evaluation of the structural elements 10 – Construction 0 0 1 2 3 4 5
2 PERIOD - Seconds Sa y()MAX Pseudo-Acceleration Spectrum Percent of Gravity BMA Engineering, Inc. – 4000 37 BMA Engineering, Inc. – 4000 38
Seismic Analysis (ASCE 4‐98) Seismic Analysis (ASCE 4‐98) • Provides requirements for designing new • Analysis provides small levels of conservatism flfacilities and evaluation of existing flfacilities to account for uncertainty • Intent of analysis methodology – Soil‐structure interaction – Output parameters maintain same non‐ – In‐structure response spectra exceedance probability as input – Structural damping – Example: produce seismic responses that have • Analysis output has slightly greater abtbout a 90% chance of not bibeing exceeddded for an probability of non‐exceedance than that for input response spectrum specified at the 84th inputs percentile
BMA Engineering, Inc. – 4000 39 BMA Engineering, Inc. – 4000 40 NUREG 0800 NUREG 0800 Section 3.0: Design of Structures, Components, Equipment, and Systems • Applicable to Structures, Systems and Components ()(SSCs) • Seismic (3.7.1 to 3.7.4)
• Two earthquake intensities Three spatial components Earthquake 1. Operating basis Seismicity & of ground motion (two Design geologic earthquake (OBE) – Safe‐shutdown earthquake ground motion (SSE) 2. Safe shutdown horizontal and one parameters conditions earthquake (SSE) vertical) – SfSafe‐operation earthqua ke ground motion (SOE) Structures, Design response spectra Ground motion systems & Site‐specific for seismic category I • Category I SSCs are SSCs designed to remain response spectra components (GMRS) GMRS SSCs at top of first functional if the SSE occurs (SSCs) surface of soil materials Design time Use 3‐compnent 1. Percentages of histories (if cancelation time history critical damping if available; otherwise SiSeism ic ana llys is o f design spectra generate using design 2. Support/foundation media category I SSCs unavailable) spectra
BMA Engineering, Inc. – 4000 41 BMA Engineering, Inc. – 4000 42
NUREG 0800 Section 3.0: Design of Structures, NUREG 0800 Section 3.0: Design of Structures, Components, Equipment, and Systems Components, Equipment, and Systems
Power Spectral Density • Seismic (3.7.1 to 3.7.4) (PSD) in in2/sec3 for • Seismic (3.7.1 to 3.7.4) Western US (WUS)
Same Level: If CSDRS > GMRS and site Not Same Level: If CSDRS > FIRS and site & 1. Ground motion & design condition are 1. Ground motion response design condition are met, response spectra (GMRS) met, CSDRS are adequate; spectra (GMRS) CSDRS are adequate; otherwise evaluate using otherwise evaluate using an 2. certified seismic design 2. certified seismic design an approv ed method* approved method* response spectra (CSDRS) response spectra (CSDRS)
Develop foundation level Develop foundation level spectra and foundation input spectra consiitsten t with Chec k if miiinimum Check if minimum spectrum is response spectra (FIRS) CSDRS for each Category I spectrum is met met SSC consistent with CSDRS for each Category I SSC
* Approved method accounts for soil-structure interaction (SSI), torsion, rocking, in- structure response, redesign, re-analysis as needed until limits are met. Cases without a certified design require developing GMRS, smoothed response spectra, foundation- level response spectra, analysis, redesign & reanalysis until meeting limits.
BMA Engineering, Inc. – 4000 43 BMA Engineering, Inc. – 4000 44 NUREG 0800 Section 3.0: Design of Structures, NUREG 0800 Section 3.0: Design of Structures, Components, Equipment, and Systems Components, Equipment, and Systems • Seismic (3.7.1 to 3.7.4) • Seismic (3.7.1 to 3.7.4) – Analysis methods: – Soil‐structure interaction (()SSI): • Response spectrum method • The random nature of the soil and rock configuration • Time history analysis method and material characteristics • Equivalent static load analysis method • Uncertainty in soil constitutive modeling (soil stiffness, damping, etc.) – Natural frequencies and response • Nonlinear soil behavior – Material, damping, stiffness and mass properties • Coupling between the structures and soil – Hydrodynamic effects • Lack of uniformity in the soil profile, which is usually assumed to be uniformly layered in all horizontal directions
BMA Engineering, Inc. – 4000 45 BMA Engineering, Inc. – 4000 46
NUREG 0800 Section 3.0: Design of Structures, NUREG 0800 Section 3.0: Design of Structures, Components, Equipment, and Systems Components, Equipment, and Systems • Seismic (3.7.1 to 3.7.4) • Seismic (3.7.1 to 3.7.4) – Soil‐structure interaction (()SSI) (()cont.): – Interaction of non‐categgyory I structures with • Effects of the flexibility of soil/rock Category I SSCs (decoupling criteria based on mass • Effects of the flexibility of basemat ratios and fundamental freqqyuency ratios) • The effect of pore water on structural responses, – Effects of parameter variation on floor responses including the effects of variability of ground‐water level – Use of equivalent vertical static factors with time • Effects of partial separation or loss of contact between – Methods used to account for torsional effects the structure (embedded portion of the structure and – Procedures for damping foundation mat) and the soil during the earthquake – Overturning moments and sliding forces • Strain‐dependent soil properties
BMA Engineering, Inc. – 4000 47 BMA Engineering, Inc. – 4000 48 NUREG 0800 Section 3.0: Design of Structures, NUREG 0800 Section 3.0: Design of Structures, Components, Equipment, and Systems Components, Equipment, and Systems • Seismic (3.7.1 to 3.7.4) • Seismic (3.7.1 to 3.7.4) – Seismic analysis to cover Categgyory 1 subsystems – Seismic analysis to cover instrumentation (per RG using similar approaches deployed for SSCs: 1.12 and RG 1.66) • Platforms • Support frame structures • Yard structures • Buried piping, tunnels and conduits ASCE • Concrete dams ASCE 7 ASCE 4 37 • Atmospheric tanks
BMA Engineering, Inc. – 4000 49 BMA Engineering, Inc. – 4000 50
Seismic Analysis (ASCE 4‐98) Seismic Analysis (ASCE 4‐98) Seismic Input Analysis • Type of Structures – All safety related structures of nuclear facilities • Seismic ground motions • Modeling of structures
• Assumes foundation material stability • Response spectra • AliAnalysis of stttructures • Determined seismic responses to be • Soil‐structure interaction combine d with responses due to dddead lldoads •Time histories modeling and analysis and other loads •Power spectral density • Input for subsystem functions seismic analysis
• Additional requirements for structures sensitive to • Special structures long period motions
BMA Engineering, Inc. – 4000 51 BMA Engineering, Inc. – 4000 52 Seismic Analysis (ASCE 4‐98) Seismic Input Seismic Input • Seismic Ground Motions • Seismic ground motions – Two orthogonal horizontal and one vertical • Response spectra components – Appropriate for geological and seismological •Time histories environment and subsurface conditions – Free field ground surface motion at top of component fdtifoundation matilterial •Power spectral density functions – Specified in terms of peak ground acceleration • Additional requirements for (PGA), peak ground velocity (PGV), and response structures sensitive to long period spectra motions
BMA Engineering, Inc. – 4000 53 BMA Engineering, Inc. – 4000 54
Seismic Input Seismic Input • Seismic Ground Motions (cont.) • Respond Spectra – peak ground displacement if required (PGD) and – General requirements Effective duration of seismic motion to be – Site‐specific horizontal response spectra included if required – Site‐independent horizontal response spectra • Nonlinear effects in foundation soils, special structures, structural response – VtilVertical response spectra – Appropriate for the magnitude and distance of the largest contributor design earthquakes to the seismic hazard for the site
BMA Engineering, Inc. – 4000 55 BMA Engineering, Inc. – 4000 56 Seismic Input Seismic Input • Respond Spectra ‐ General Requirements • Respond Spectra ‐ Site‐Specific Horizontal Response – Either site specific or standard Spectra – Response spectrum for an intermediate damppging – Necessary for sites with soft soils, i.e., soils having factor a low strain shear wave velocity of no greater – Consider two potential ground motions separately than 750 ft/s averages for the top 100 ft of soil – Sites of hgh frequency motions > 33 Hz – Facilities within 15 km of active fault
BMA Engineering, Inc. – 4000 57 BMA Engineering, Inc. – 4000 58
Seismic Input • RdRespond Spectra ‐ Site‐SifiSpecific HHiorizonta l Response Seismic Input Spectra: a comparison (high‐frequency content) • Respond Spectra ‐ Site‐Independent Horizontal 121.2 Response Spectra using:
1.0 AP 1000 – Spectral acceleration (Sa)
0.8 – Spectral velocity (Sv) Bellefonte (g) nn – Spectral displacement (Sd) 0.6 • Computed using the dynamic amplification factors Acceleratio 0.4 Shearon • Instead of median, Harris 0.2 other exceedance probability can be 0.0 used 1 10 100 Frequency (Hz)
‐4 BMA Engineering,Comparisons Inc. – 4000 are between certified design spectra and 10 site specific spectra 59 BMA Engineering, Inc. – 4000 60 Seismic Input Seismic Input • Respond Spectra ‐ Site‐ • Respond Spectra ‐ Vertical Response Spectra Independent – Use a value of 2/3 of the corresponding horizontal Horizontal Response component throughout the freqyquency range Spectra – For source to site distance < 15 km, use the • Example: following factors Median‐shdhaped response spectrum for • 1 for frequency > 5 Hz hlhorizontal motion • 2/3 at frequency < 3 Hz scaled to 0.3g peak • Linear interpolation for cases in between 3 and 5, unless a site‐specific evaluation is conducted ground accellieration, 5% damping, soil site
BMA Engineering, Inc. – 4000 61 BMA Engineering, Inc. – 4000 62
Seismic Input Seismic Input • Time Histories • Time Histories – Use duration – Compute spectral values envelope at sufficient points function for – Use orthogonal each components direction
BMA Engineering, Inc. – 4000 63 BMA Engineering, Inc. – 4000 64 Seismic Input Seismic Input • Power Spectral Density (PSD) Functions – PSD is computed from time histories using Fourier transformation – For zero‐mean stochastic processes, spectral density is the variance as a function of frequency – It is related to energy as a function of frequency
BMA Engineering, Inc. – 4000 65 BMA Engineering, Inc. – 4000 66
Seismic Input Seismic Analysis (ASCE 4‐98) Analysis • Additional Requirements for Structures • Modeling of structures Sensitive to Long Period Motions • AliAnalysis of stttructures – Structures for which isolation techniques, liquefaction and hydrodynamic effects are • Soil‐structure interaction modeling considered and analysis – Response spectral for 002.2 to 33 Hz, with smaller frequencies requiring site‐specific analysis • Input for subsystem seismic analysis – Time his tor ies can be used for specilial cases • Special structures
BMA Engineering, Inc. – 4000 67 BMA Engineering, Inc. – 4000 68 Seismic Analysis Seismic Analysis
• Modeling of Structures • Modeling of Structures ‐ General Requirements – General requirements – Models for horizontal and vertical motions can be – Structural material properties separate if the motions are uncoupled; otherwise – Modeling of stiffness 3‐D analysis is required – MdliModeling of mass – One‐step metho d for seiiismic response analilysis – Modeling of damping – Multistep method for seismic response analysis – Modeling of hydrodynamic effects • In the first step, and overall response is obtained and used as an input to the second step, and so on – Dynamic coupling criteria – Discretization considerations (mesh size, finite – Requirements for modeling specific structures element type, reduction of degrees of freedom, etc.)
BMA Engineering, Inc. – 4000 69 BMA Engineering, Inc. – 4000 70
Seismic Analysis Seismic Analysis
• Finite • Finite element element analysis analysis
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BMA Engineering, Inc. – 4000 75 BMA Engineering, Inc. – 4000 76 Seismic Analysis Seismic Analysis • Modeling of Structures ‐ Structural Material • Modeling of Structures Properties – Stiffness – Modulus of elasticity for concrete (ACI code) , • Steel and aluminum steel (29,000 ksi), aluminum (10,000 ksi) • Concrete (cracked or un‐cracked) – PiPoisson ’s ratio for concrete (0. 17) , sttleel (0. 3), – Mass aluminum (0.3) • Discretization – Damping • MdlModal mass to ildinclude all tibttributary mass such as fixe d equipment, piping, etc. – DiDamping • Superposition of properties for a system of subsystems
BMA Engineering, Inc. – 4000 77 BMA Engineering, Inc. – 4000 78
Seismic Analysis Seismic Analysis Dynamic coupling criteria Modeling of hdhydro dynam ic effects
BMA Engineering, Inc. – 4000 79 BMA Engineering, Inc. – 4000 80 Seismic Analysis Seismic Analysis • Requirements for Modeling Specific Structures • Analysis of Structures – Structures with rigid floors – Time history method • Degrees of freedom – Response spectrum method • Model type, e.g., lumped sum mass – Complex frequency response method – Structures with flexible floors – Equivalent static load method – Framed structures • Three orthogonal components – Shear‐wall structures – Two horizontal – Plate and shell structures – One vertica l – Adjacent structures (spacing requirements)
BMA Engineering, Inc. – 4000 81 BMA Engineering, Inc. – 4000 82
Seismic Analysis Seismic Analysis • Time history method: linear methods • Approximations – The loads are applied directly to the structure [M ]{X}[C]{X }[K]{X} [M ]{U h}ug where M = mass,,pg,, C = damping, K = stiffness, – In the case of a real earthqq,uake, X = displacement, X dot = velocity, displacements are applied at the foundation of X two-dots = acceleration,,, U = influence vector, the real structure u = ground acceleration • Discretization, min step size • Solution methods – MdlModal superpos ition – Integration
BMA Engineering, Inc. – 4000 83 BMA Engineering, Inc. – 4000 84 Seismic Analysis Seismic Analysis • Time history method • Response spectrum method • Sources of nonlinearities – Linear methods – Materials – Nonlinear methods – Geometries • Complex frequency response method – RtihitResponse time history – Transfer functions (ratios of Fourier transform of response to Fourier transform of input) •Equivalent static load method – Cantilever model with uniform mass distribution
BMA Engineering, Inc. – 4000 85 BMA Engineering, Inc. – 4000 86
Soil‐Structure Interaction (()SSI) Soil‐Structure Interaction (()SSI) • Soil-structure interaction modeling and analysis • Fixed‐base analysis (nonlinearity, uncertainties) – Required for structures not supported by rock or rock‐like soil foundation material – Two methods • Direct method • Impedance function approach – Fixed‐base analysis
BMA Engineering, Inc. – 4000 87 BMA Engineering, Inc. – 4000 88 Soil‐Structure Interaction (()SSI) Soil‐Structure Interaction (()SSI) • Fixed‐base analysis (nonlinearity, uncertainties) • Subsurface material properties – Shear modulus – Horizontal damping ratio – Poisson’s ratio
BMA Engineering, Inc. – 4000 89 BMA Engineering, Inc. – 4000 90
Shear Modulus Damppging Ratio
BMA Engineering, Inc. – 4000 91 BMA Engineering, Inc. – 4000 92 Damping Stiffness Soil‐Structure Interaction (()SSI) • Direct method, steps: – Locate the bottom and lateral boundaries of the SSI model – Establish input motion at the boundaries • Soil element size • Time step and frequency increment
BMA Engineering, Inc. – 4000 93 BMA Engineering, Inc. – 4000 94
Soil‐Structure Interaction (()SSI) Soil‐Structure Interaction (()SSI) • Impedance method, steps: • Input for sub‐system seismic analysis – Determine the input motion to the mass‐less rigid foundation – Generation of seismic input for all systems and –Determine the foundation impedance (defined as force‐ components which are not sppyecifically modeled in resistance to motion measured as velli)ocity) ffiunction the main dynamic model –Analyze the coupled soil‐structure system • In‐structure response spectra • Impedance function can be determined using – Time history method – Equivalent dimensions for mat foundations – Equivalent impedance for layered soil sites – Frequency intervals – Approximations relating to embedded foundations – Uncertainties and interpolation • Analysis of coupled soil‐structural system • In‐structure time history
BMA Engineering, Inc. – 4000 95 BMA Engineering, Inc. – 4000 96 In Structure Response Special Structures • Buried pipes and conduits • Earth‐retaining walls • Above ground vertical tanks • Raceways including cable trays and conduit systems • Base isolated structures
BMA Engineering, Inc. – 4000 97 BMA Engineering, Inc. – 4000 98
Special Structures Damppging of Conduits • Earth‐retaining walls
BMA Engineering, Inc. – 4000 99 BMA Engineering, Inc. – 4000 100 Special Structures Special Structures • Earth‐retaining walls
BMA Engineering, Inc. – 4000 101 BMA Engineering, Inc. – 4000 102
Seismic Probabilistic Risk Seismic Probabilistic Risk AtAssessment (SPRA) AtAssessment (SPRA)
BMA Engineering, Inc. – 4000 103 BMA Engineering, Inc. – 4000 104 Seismic Probabilistic Risk Seismic Probabilistic Risk AtAssessment (SPRA) AtAssessment (SPRA)
SMA = Seismic Margin Earthquake (larger than the des ign bas is )
BMA Engineering, Inc. – 4000 105 BMA Engineering, Inc. – 4000 106
Seismic Probabilistic Risk Seismic Probabilistic Risk AtAssessment (SPRA) AtAssessment (SPRA)
HCLPF = High Confidence Low SMA = Seismic Margin Assessment Probability of Failure
BMA Engineering, Inc. – 4000 107 BMA Engineering, Inc. – 4000 108 Load Factors and Load Combinations Load Factors and Load Combinations • Normal Loads: encountered during normal plant start‐up, op,peration, and shutdown • Severe Environmental Loads: encountered infrequently during the service life ANSI/AISC N690‐06 ANSI/AISC N690‐06
BMA Engineering, Inc. – 4000 109 BMA Engineering, Inc. – 4000 110
Load Factors and Load Combinations Load Factors and Load Combinations ANSI/AISC ANSI/AISC • Extreme Environmental Loads: highly N690‐06 • Abnormal Loads: generated by a N690‐06 improbable bbtut are used as a design basis postu lated high‐energy pipe break accident used as a design basis
BMA Engineering, Inc. – 4000 111 BMA Engineering, Inc. – 4000 112 Load Factors and Load Combinations Load Factors and Load Combinations ANSI/AISC ANSI/AISC • Load and Resistance Factor Design N690‐06 • LRFD Normal Load Combinations N690‐06 (LRFD)
– The design strength (φRn) of each structural component shall be equal to or greater than the required strength (Ru), determined from the appropriate critical combinations of the loads – The most critical structural effect may occur when one or more loads are not acting
BMA Engineering, Inc. – 4000 113 BMA Engineering, Inc. – 4000 114
Load Factors and Load Combinations Load Factors and Load Combinations ANSI/AISC ANSI/AISC • LRFD Severe Load Combinations N690‐06 • Allowable Stress Design (ASD) N690‐06
– The allowa ble strength (Rn/Ω) of each structural component shall be equal to or greater than the
requidired strength (Ra), diddetermined from the appropriate critical combinations of the loads • LRFD Extreme and Abnormal Load Combinations – The most critical structural effects may occur when one or more loads are not acting
BMA Engineering, Inc. – 4000 115 BMA Engineering, Inc. – 4000 116 Load Factors and Load Combinations Load Factors and Load Combinations ANSI/AISC ANSI/AISC • ASD Normal Load Combinations N690‐06 • ASD Severe Load Combinations N690‐06
• LRFD Extreme and Abnormal Load Combinations
BMA Engineering, Inc. – 4000 117 BMA Engineering, Inc. – 4000 118
4000. Loads, Load Factors, and Load Design Loads on Structures During Construction Combinations [ASCE Standard 37‐02] • General • Minimum Design Loads for Buildings and – Other Structures [ASCE Standard 7‐05] Purpose: Minimum design load requirements diduring consttitruction •Seismic Analysis of Safety‐Related Nuclear – Scope: Partially completed structures and Structures and Commentary [ASCE temporary structures Standard 4‐98] – Basic Requirements: • •Design Loads on Structures During Safety Construction [ASCE Standard 37‐02] • Structural integgyrity • Serviceability • Load types • Construction methods BMA Engineering, Inc. – 4000 119 BMA Engineering, Inc. – 4000 120 Design Loads on Structures During Construction Design Loads on Structures During Construction [ASCE Standard 37‐02] [ASCE Standard 37‐02] • Loads and Load Combinations • Loads and Load Combinations – Loads Specified – Load Combinations and Load Factors for Strength • Dead and live loads Design • Construction loads (temporary structures, etc.) Combined design load = dead load and/or • Material loads material load + loads at their max value + loads at • Construction procedure loads their APT reduced values • Lateral earth pressure • Environmental loads (thermal, snow, earthquake, rain, APT = arbitrary point in time ice)
BMA Engineering, Inc. – 4000 121 BMA Engineering, Inc. – 4000 122
Design Loads on Structures During Construction Design Loads on Structures During Construction [ASCE Standard 37‐02] [ASCE Standard 37‐02] • Construction Loads • Basic Combinations (example)
– General Requirement 1.4 D + 1.4 CD + 1.2 CFML + 1.4 CVML – Material Loads D = dead load
– Personnel and Equipment Load CD = construction dead load
– Horizontal Construction Loads CFML = fixed material load
– Erection and Fitting Forces CVML = variable material load – Eqqpuipment Reactions – Form Pressure – Application of Loads
BMA Engineering, Inc. – 4000 123 BMA Engineering, Inc. – 4000 124 Design Loads on Structures During Construction Computer Aided Analysis and Design [ASCE Standard 37‐02] • Finite element analysis • Loads and Load Combinations • Software – Overturning and sliding – Allowable Stress Design – Bridges (use AASHTO Code)
BMA Engineering, Inc. – 4000 125 BMA Engineering, Inc. – 4000 126
Computer Aided Analysis and Design Computer Aided Analysis and Design Steps Example Elements and degrees of freedom
• 2D or 3D point‐to‐point or thru curve Beam Elements • 6 translational DOFs at nodes • Shown in light blue with cross‐section (Shown here in red for clarity) • Well suited to represent beams with a 10:1 slenderness ratio
BMA Engineering, Inc. – 4000 127 BMA Engineering, Inc. – 4000 128 Computer Aided Analysis and Design Computer Aided Analysis and Design Example Elements and degrees of freedom Materials
• Tetrahedral shape • 3 translational DOFs at nodes Shell element • Rotational constraints not required • Shown in blue • Ideal for solid bodies with large cross‐ sectional areas • Not well suited for thin bodies
BMA Engineering, Inc. – 4000 129 BMA Engineering, Inc. – 4000 130
Computer Aided Analysis and Design Computer Aided Analysis and Design Constraints Symmetry constraints
BMA Engineering, Inc. – 4000 131 BMA Engineering, Inc. – 4000 132 Computer Aided Analysis and Design Computer Aided Analysis and Design
Loads Mesh and control
BMA Engineering, Inc. – 4000 133 BMA Engineering, Inc. – 4000 134
Computer Aided Analysis and Design Computer Aided Analysis and Design
Bonded Connections and Springs Analysis definition
Free
SiSprings
Contact –no Interpenetration
BMA Engineering, Inc. – 4000 135 BMA Engineering, Inc. – 4000 136 Computer Aided Analysis and Design Computer Aided Analysis and Design Results Results
BMA Engineering, Inc. – 4000 137 BMA Engineering, Inc. – 4000 138
Open source software (source Wikipedia) Open source software (source Wikipedia) Computer Aided Analysis and Design Computer Aided Analysis and Design • CalculiX is an Open Source FEA project. The • Elmer FEM solver: Open source multiphysical solver uses a partially compatible ABAQUS file simulation software developed by Finnish format. The pp/pre/post‐processor generates Ministry of Education's CSC, written in C, C++ input data for many FEA and CFD applications and Fortran • Code Aster: French software written in Python • FEniCS Project: a LGPL‐licensed software and Fortran, GPL license package developed by American and • DUNE, Distributed and Unified Numerics European researchers Environment GPL Version 2 with Run‐Time • Hermes Project: Modular C/C++ library for Exception, written in C++ rapid prototyping of space‐ and space‐time • FEBio, Fin ite Elements for Biomec han ics adaptive hp‐FEM solvers
BMA Engineering, Inc. – 4000 139 BMA Engineering, Inc. – 4000 140 Open source software (source Wikipedia) Commercial software (source Wikipedia) Computer Aided Analysis and Design Computer Aided Analysis and Design • Impact: Dynamic Finite Element Program • Abaqus: Franco‐American software from Suite, for dynamic events like crashes, written SIMULIA, owned by Dassault Systemes in Java, GNU license • ADINA • OOFEM: Object Oriented Finite EleMent • ALGOR Incorporated solver, written in C++, GPL v2 license • ANSA: An advanced CAE pre‐processing • OpenSees is an Open System for Earthquake software for complete model build up. Engineering Simulation • ANSYS: American software • Z88: FEM‐software available for Windows and • COMSOL Multiphysics COMSOL Multiphysics Linux/UNIX, written in C, GPL license Finite Element Analysis Software formerly Femlab BMA Engineering, Inc. – 4000 141 BMA Engineering, Inc. – 4000 142
Commercial software (source Wikipedia) Commercial software (source Wikipedia) Computer Aided Analysis and Design Computer Aided Analysis and Design • Femap, Siemens PLM Software: A pre and post • MADYMO: TASS ‐ TNO Automotive Safety processor for Windows Solutions • FlexPDE • Nastran: American software • Flux : American electromagnetic and thermal • nastran/EM: Nastran Suit for highly advanced FEA Durabilty & NVH Analyses of Engines; born • JMAG: Japanese software Actran: Belgian from the AK32 Benchmark of Audi, BMW, Software (Acoustic) Daimler, Porsche & VW; Source Code available • LS‐DYNA, LSTC ‐ Livermore SftSoftware • NEi Fusion, NEi Software: 3D CAD modeler + Technology Corporation Nastran FEA • LUSAS: UK Software BMA Engineering, Inc. – 4000 143 BMA Engineering, Inc. – 4000 144 Commercial software (source Wikipedia) Commercial software (source Wikipedia) Computer Aided Analysis and Design Computer Aided Analysis and Design • NEi Nastran, NEi Software: General purpose • Range Software: Multiphysics simulation Finite Element Analysis software • NEi Works, NEi Software: Embedded Nastran • RFEM for SolidWorks users • SAMCEF: CAE package developed by the • NISA: Indian software Belgian company • PZFlex: American software for wave • SAP2000: American software propagation and piezoelectric devices • STRAND7: Developed in Sydney Australia by • QikfildQuickfield : Phys ics siltiimulating software Stran d7 Pty. Ltd. MMktdarketed as Straus 7 in • Radioss: A linear and nonlinear solver owned Europe by Altair Engineering BMA Engineering, Inc. – 4000 145 BMA Engineering, Inc. – 4000 146
Commercial software (source Wikipedia) Computer Aided Analysis and Design 4000. Loads, Load Factors, and Load Combinations • StressCheck developed by ESRD, Inc USA • Vflo™: Physics‐based distributed hydrologic • Objective and Scope Met modeling software, developed by Vieux & – Introduce loads, load factors, and load Associates, Inc. combinations for nuclear‐related civil & structural design and construction • Zébulon: French software – Present and discuss • Types of loads and their computational principles • Load factors • Load combinations • Focus on seismic loads • Computer aided analysis and design (brief)
BMA Engineering, Inc. – 4000 147 BMA Engineering, Inc. – 4000 148 Scope: Primary Documents Covered Completed Items of Overall Outline
1000. Introduction • Minimum Design Loads for Buildings and Other Structures [ASCE Standard 7‐05] 2000. Federal Regulations, Guides, and Reports 3000. Site Investigation •Seismic Analysis of Safety‐Related Nuclear 4000. Loads, Load Factors, and Load Combinations Structures and Commentary [ASCE 5000. Concrete Structures and Construction Standard 4‐98] 6000. Steel Structures and Construction 7000. General Construction Methods •Design Loads on Structures During 8000. Exams and Course Evaluation Construction [ASCE Standard 37‐02] 9000. References and Sources
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