Construction Loading Analysis 2010 Contractor Engineer Conference Bill Dreher Structures Design Chief WisDOT

Standard Specification ChangeStandard Specification Change – Loads on Structures Research ProjectResearch Project –WHRP – Development of a Bridge Construction Live Load Analysis Guide

Loads on Structures (1) Demonstrate that all loads on structures within the project limits throughout the duration of the contract do not exceed the structural capacity of the structure. If the engineer directs, submit stamped and signed copies of analyses and associated calculations performed by a professional engineer (PE) registered in the state of Wisconsin to the engineer and to the department's bureau of structures. Do not begin construction operations or move a heavy load across a structure without the engineer's written authorization.

Loads on Structures Ensure safety and structural integrityEnsure safety and structural integrity Contractor is responsible for analyzing structures with applied construction loadsContractor is responsible for analyzing structures with applied construction loads Stamped and signed by Wisconsin P.E. when directed by engineerStamped and signed by Wisconsin P.E. when directed by engineer Information (including latest inspection reports) available via Highway Structures Information systemInformation (including latest inspection reports) available via Highway Structures Information system

Loads on Structures (2) If a PE's analysis is required, determine capacity at the operating load level using the same AASHTO specification the structure was rated under. Include materials, equipment, and other construction or vehicular loads in the analyses. If under public traffic, also include the Wisconsin standard permit vehicle (Wis-SPV) as shown in chapter 45 of the department's bridge manual. The structure must be capable of carrying a Wis-SPV load equal to or greater than 100,000 pounds in addition to construction loads. The engineer's written authorization must be accompanied by a copy of the analysis stamped accepted by department's bureau of structures before proceeding.

Loads on Structures Operating Load FactorsOperating Load Factors AASHTO SpecificationAASHTO Specification –LFD –LRFD Include Wisconsin SPV if carrying public trafficInclude Wisconsin SPV if carrying public traffic

Loads on Structures (3) Except as required to accommodate public traffic or to complete the deck pour, do not operate heavy equipment or impose vehicular live loads on lanes adjacent to freshly placed concrete decks until it develops sufficient strength to open it to service under

Loads on Structures No heavy equipment or vehicle loads on lanes adjacent to freshly placed deck –Minimize vibrations that affect development of concrete strength and bond to reinforcement

Research Project WHRP – Development of a Bridge Construction Live Load Analysis Guide

Research Project Collins Engineering, Inc.Collins Engineering, Inc. Literature ReviewLiterature Review Current information on the effects of construction loadsCurrent information on the effects of construction loads On-going research projectsOn-going research projects Data on equipment loadsData on equipment loads Studies on load distributionStudies on load distribution

Research Project Present Practices SurveyPresent Practices Survey State DOT’s – existing spec’s or under developmentState DOT’s – existing spec’s or under development Wisconsin Contractors – typical construction practices and equipmentWisconsin Contractors – typical construction practices and equipment –Please participate! Load Model StudiesLoad Model Studies Live load distribution factorsLive load distribution factors

Research Project Analysis Guide / HandbookAnalysis Guide / Handbook Permissible analysis approaches and stress limitsPermissible analysis approaches and stress limits Equipment loadsEquipment loads –Variable crane configurations –Track, outrigger loads –Impact effects due to equipment and operations (breaking concrete, pile driving)

Research Project Analysis Guide / HandbookAnalysis Guide / Handbook Guidance to control and minimize load effectsGuidance to control and minimize load effects –Crane position –Load transfer mats

Research Project Recommended special provisions and spec languageRecommended special provisions and spec language

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