Safe and Sustainable Parking Garage Live Loads In The Age Of The Electric Vehicle

Safe and Sustainable Parking Garage Live Loads In The Age Of The Electric Vehicle

The research consists of four tasks: (1) Data acquisition; (2) Data analysis; (3) Stochastic load modeling; (4) Load analysis and design load recommendation. Data on vehicle fleet compositions will be acquired from S&P Global or alternate sources. Data will be acquired that describes fleet compositions for all 50 states and for multiple years over approximately the last decade. The datasets will include vehicle make, model and model-year, in addition to vehicle weights. The raw vehicle fleet data will be post-processed to establish probability distributions for vehicle fleet characteristics including make, model, model-year and vehicle weight. Such analysis will be performed for each database corresponding to particular states and years in order to permit evaluation of temporal and geographic variation of fleet characteristics. A stochastic model, possibly following the approach of Wen and Yeo and extreme value analysis as used recently with German data will be implemented for parking garage live loads. The purpose of the model is to be able to conduct Monte Carlo simulation or other probabilistic analysis of the equivalent uniform design load (EUDL) imposed on parking garage floors by vehicles. The model will simulate vehicles parking on a garage floor with the vehicle type (make, model, year and weight) sampled from the fleet distributions established in task (2). Monte Carlo simulation using this model will result in sufficient samples of garage live load scenarios to establish, in task (4), distributions of effective live loads on garage floors and, through analysis of structural demands on structural members, EUDL values. In addition to uniform, random, assignment of vehicles to parking spaces in the model, special cases will be investigated corresponding to EV concentration around charging stations and possible fleet parking areas in which single vehicle types may be concentrated. This research will provide a probabilistic and stochastic structural approach to the problem recently described in purely vehicle weight analysis in Structure magazine. Upon completion of the research tasks, a final technical report will be prepared that addresses two questions: (1) has the current 40 psf value been consistent with historical load scenarios? and (2) do data, simulations, load assessment and structural analysis support a revision to the 40 psf values and, if so, to what value?

• Grant Details

  Project

  Safe and Sustainable Parking Garage Live Loads In The Age Of The Electric Vehicle

  Grantee

  University of Colorado

  Category

  Performance-Based Design

  Grant #

  RGA #05-24

  Award Amount

  $87,500

  Grant Period

  15 October 2024 - 15 July 2025

  Grant Status

  Complete

  Principal Investigators

  Dr. Ross B. Corotis, P.E., University of Colorado Boulder; Dr Sanjay Arwade, University of Massachusetts

  Industry Champions

  Emily Guglielmo, Martin / Martin; Cole Graveen, Raths, Raths & Johnson; Erik Madsen, DCI + Madsen

  CPF Allies

  ASCE 7-28 Dead & Live Load Subcommittee of ASCE/SEI, the Structural Engineers Association of New York (SEAoNY), and the New York City Department of Buildings

  Supporters

  Simpson Gumpertz & Heger (SGH), HGA Architects, Desimone Engineering, National Council of Structural Engineers Associations (NCSEA), Rimkus, Walter P Moore, Martin / Martin, DCI Engineering, Parking Consultants Council (PCC), and the Precast/Prestressed Concrete Institute (PCI)

• Resources / Downloads

  • Safe and Sustainable Parking Garage Live Loads in the Age of the Electric Vehicle

    Abstract: Parking garages, loaded primarily by sets of vehicles sampled from the prevailing vehicle fleet, are subject to changes in loads and demand and vehicle purchasing preferences of the market shift over time. As electric vehicles (EVs) continue to become more popular in the US and globally, the question of whether a shift to EVs, with their significant battery weight, indicates a change in the prescribed design live load in the ASCE 7 specification. This study implements the stochastic live load method that was used to establish the existing 40 psf garage live load value in ASCE 7, but using data reflective of the current state of the US vehicle fleet. Additionally, an approach is introduced to account for future increased adoption of EVs. Corresponding equivalent uniform design loads (EUDLs) are calculated for a wide variety of cases, considering geographic and temporal variation as well as a variety of EV adoption scenarios. In all but the most extreme cases of EV adoption and EV weight, calculated EUDLs are equal to or lower than 40 psf. In the cases where the EUDL exceeds 40 psf it is prudent to consider the additional safety margin provided by the presence of a load factor greater than 1.0 in the specification of load combinations. Using direct simulation of loading and column axial forces on multiple levels of a parking garage, it is found that a 10% reduction in live load is supported for columns supporting multiple levels.

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