Construction Loading
2010 Contractor Engineer Conference
Bill Dreher
Structures Design Chief
• Standard Specification Change
– 108.7.3 Loads on Structures
• Research Project
– WHRP – Development of a Bridge
Construction Live Load Analysis Guide
108.7.3 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.
108.7.3 Loads on Structures
• Ensure safety and structural integrity
• Contractor is responsible for analyzing
structures with applied construction
• Stamped and signed by Wisconsin P.E.
when directed by engineer
• Information (including latest inspection
reports) available via Highway
Structures Information system
108.7.3 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.
108.7.3 Loads on Structures
• Operating Load Factors
• AASHTO Specification
• Include Wisconsin SPV if carrying public
108.7.3 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 502.3.10.1.
108.7.3 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
Research Project
WHRP – Development of a Bridge
Construction Live Load Analysis Guide
Research Project
• Collins Engineering, Inc.
• Literature Review
• Current information on the effects of
construction loads
• On-going research projects
• Data on equipment loads
• Studies on load distribution
Research Project
• Present Practices Survey
• State DOT’s – existing spec’s or under
• Wisconsin Contractors – typical
construction practices and equipment
– Please participate!
• Load Model Studies
• Live load distribution factors
Research Project
• Analysis Guide/Handbook
• Permissible analysis approaches and
stress limits
• Equipment loads
– Variable crane configurations
– Track, outrigger loads
– Impact effects due to equipment and
operations (breaking concrete, pile
Research Project
• Analysis Guide/Handbook
• Guidance to control and minimize load
– Crane position
– Load transfer mats
Research Project
• Recommended special provisions and
spec language
Thank You!

WisDOT Major Highway Projects Cost Estimating Workshop