Bridge Rating Practices and Policies for Overweight Vehicles (2006) / Chapter Skim
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Appendix C - Responses to Questionnaire
Appendix C - Responses to Questionnaire
Pages 36-107
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From page 36... ...
37 APPENDIX C Responses to Questionnaire
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From page 37... ...
A review of the load rating may be required. Type 3 -- Single trip oversize/overweight permits -- These permits are issued to vehicles that do not conform with either 17 AAC 25.012 or 17 AAC 25.013.
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From page 38... ...
Annual permitted trucks must obey the load restrictions of the Route Capacity Map for all state highways they travel. Type 2 -- Single trip permits -- May be issued to vehicles carrying nondivisible loads that do not have annual permits or weigh in excess of 200 kips.
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From page 39... ...
Type 2 -- Non-reducible: 130 kips on five or more axles, single trips and annual basis, no load rating required. Type 3 -- Superloads over 130 kips, individual basis, load rating required for each bridge.
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From page 40... ...
Any overweight vehicle requests other than the above require "Single Trip Permits" and individual bridge studies. These permits can only be issued by the NCDOT Permit Unit.
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A bridge analysis is done when the GVW exceeds 150,000 lb or when a combination of axles exceeds bridge weight limitations. Type 2 -- Single trip permits on self-propelled overweight vehicle.
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From page 42... ...
. The only one that requires a bridge analysis is single trip permits that fail our screening algorithm.
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From page 43... ...
WI Type 1 -- Annual permits to 170,000 lb. Type 2 -- Single trip permits to any weight -- actual axle weights are evaluated for each structure on route.
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From page 44... ...
These bridges would then be reviewed to see whether they are suitable for the proposed load. No New Brunswick Type 1 -- Single trip permits -- review existing load ratings.
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From page 45... ...
Type 2 -- Single trip permits with police escort exceeding: 4.15 m height, 3.7 m width, 24.5 m length, 63,500 kg. Type 3 -- Annual permits: maximum 4.15 m height, maximum 3.7 m width, maximum 23.0 m length, maximum 63,500 kg weight.
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From page 46... ...
CO 1. Single trip permits <200,000 lb, and/or <17 ft wide.
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From page 47... ...
2. Single trip permits for nondivisible loads weighing >200,000 lb.
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From page 48... ...
2. Single trip permit.
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From page 49... ...
3. Self-issue single trip if any combination of axles exceeding bridge weight limitations.
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WI Annual permits <170,000 lb. Single trip permits.
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Note: (1) Permit vehicles with GVW falling within the range of Ontario Bridge Formula + 10,000 kg, no load rating is required for bridges.
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Single trip permits: >4.15 m height, 2.59 m width, 21.33 m length, 50,000 kg.
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From page 53... ...
Also, considering more flexible weight policies for superload vehicles between 15 and 20 ft wide. CO No CT No DE No DC FL We are in the process of evaluating the impact of the new LRFR code on our operations, design, and load rating policies.
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From page 54... ...
Toronto The entire process is currently under review. We are looking to allow wider vehicles under the Annual Permit, and allowing private escorts in some circumstances, centralizing the office from which the permits are issued.
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Unknown A single state DOT office. AK Yes 6 No A separate state office (Bridge Design)
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ND Several state ND Highway Patrol offices 3 Yes Load rating by one single state office: NDDOT Bridge Division. OH Yes 9 No A separate state office (Office of Structural Engineering)
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PA 12 offices -- 80% auto issued 40 Yes State district offices PR Yes Yes Same state office RI 2 0 No A DOT office SC Yes 7 Yes Same state office SD SD Highway Patrol -- Motor Carrier Division Yes Only in certain cases are overload requests evaluated by SDDOT -- Bridge Division Office TN Yes 11 Yes A separate state office: Structure Inventory & Appraisal Office linked permit issuance office by a permit management software system. TX Yes 80 Yes Private consultants with final approval of Bridge Division UT VT Yes A separate state office VA 10 offices 2 Yes State central office WA 27 offices 15 No Yes State Bridge Preservation Office Some local agencies have the capability of load rating, others send them to consultants.
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From page 58... ...
Alberta Yes 1 No Same province office Calgary Yes <1 No City of Calgary Structures and Bridges Group New Brunswick 14 offices 39 Yes A single province office Newfoundland Yes <2 A province office (Bridge Office) Northwest Territories Yes Yes Same province office Ontario Yes Yes Same province office Ottawa Yes <3 Yes Same local agency offices PEI Yes 0.2 Yes Same province office Quebec Yes 4+ Yes Same province office Toronto 4 offices 3 No Same offices and Bridges & Expressways Unit Summary: Adequate staffing?
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From page 59... ...
KY The Justice Cabinet (part of state government) TN State police LA TX State police, local police ME UT MD VT DOT, state police MA State police VA State police, local police MI WA State police, local police MN State police, local police WV MS DOT WI State police MO Missouri law enforcement branches WY DOT No response received if empty.
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From page 60... ...
61 Jurisdiction Enforcement Provided by Alberta DOT, province police, local police Calgary Local police New Brunswick Province police, local police, Royal Canadian Mounted Police Newfoundland Department of Government Services with help from provincial and local police Northwest Territories DOT Ontario DOT Ottawa Province police, local police PEI DOT, province police Quebec DOT, province police, local police Toronto Province police, local police TABLE C3-5B OS/OW ENFORCEMENT PROVIDER (CANADA)
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OR Yes Continuous trip permits in 10 min. Single trip permits in 10 min to 1 h.
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VT Yes VA Yes Single trip issues: within 15 min of call. Blanket: 2 to 3 days.
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From page 63... ...
This chart is sometimes conservative. If many electronic models existed, allowable weights could be based on analysis of the bridge for the actual permit vehicle.
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NY 17,500 100% 75% Yes Ratings can be regenerated based on each individual permit vehicle. NC 14,000 99.9% 0% No ND 30% -- estimated.
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83.7% 28.40% 65% Yes Consistency would be the biggest benefit provided all states were to One less hurdle to overcome. Electronic models provide the data to allow a more rapid analysis of permit vehicle requests.
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From page 66... ...
It is a quick way to check the rating of a specific bridge, but for Class 6 permits with a long route it is at the moment impossible to analyze all the bridges that way. Toronto 349 95% 0% Summary Total responses 8 Yes 3 No 5 TABLE C4-1B POPULATION OF LOAD RATED BRIDGES AND ELECTRONICALLY MODELED BRIDGES (CANADA)
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NY State agency personnel, state-contracted consultants DE State agency personnel NC State agency personnel (Bridge Maintenance Unit) DC ND State agency personnel FL Bridge load rating is not reviewed in the course of routine bridge evaluation performed to issue permits.
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Ottawa PEI Province agency personnel Quebec Province agency personnel, province-contracted consultants Toronto No response received if empty.
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Article 10.57 limits stresses to prevent permanent deflections of steel girders. Y To obtain maximum safe capacity from bridges to facilitate movement of overweight permit vehicles.
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LA ME MD MA Y Y Permit vehicles are typically thought of as infrequently applied loads that justify the use of the operating level capacity. MI MN Y Y Virtis Y Virtis To permit heaviest vehicle AASHTO safely allows with sound engineering judgment.
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From page 71... ...
For superloads, an individual analysis is performed and the resulting operating rating is also used. These are used since there are a relatively low number of permit vehicles crossing our bridges as compared with the fatigue loading cycles given in AASHTO.
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From page 72... ...
do not have this width and so the IR and OR values cannot be applied to review the bridges. UT VT Y Y Y Y Historical load rating files exist for a high percentage of our structures, which allows us to provide, with limited staffing, a quick turnaround time on the engineering studies needed.
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Y This represents loads the bridge would see on a less than routine basis. Summary: T o t a l r e s p o n s e s : 44 44 44 44 44 T o t a l r e s p o n s e s : 44 44 Yes: 1 23 42 34 25 Yes: 0 41 No response received if empty.
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From page 74... ...
Yes Yes Yes Yes For single trip permits. AZ Yes Yes Yes Yes Yes AR Yes Yes Yes Yes CA Allow about 10% more axle weight for permit vehicle due to the improbable occurrence of sideby-side permit vehicles.
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NM Yes Yes Yes Yes For loads over 140,000 lb. NY Yes Yes Yes Yes NC Yes Yes Yes Yes Yes ND Yes Yes OH Two permit vehicles side by side.
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From page 76... ...
Yes Yes Yes Yes Sometimes require truck to crab. Mostly superloads, a few single trip.
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From page 77... ...
However, ministry guidelines allows a heavier permit load than provided by OBF if travel restrictions are imposed; i.e., permit vehicles would be controlled when crossing bridges and police escort would be required. Yes Yes Yes Imposed in specific cases to obtain a higher allowable load than allowed by Ontario Bridge Formula, for permit vehicles exceeding 70,000 kg.
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From page 79... ...
MO Y modified BARS Plan to adopt Virtis Y Y Currently transitioning to Virtis. MT Y BRASS–DIST Y Virtis Y Y Visual analysis Virtis NE Y None Y Y NV Y IAI-BDS; BRASS- Girder Y NH NJ In-house program comparing the weights of permit vehicle and legal trucks, then finding the allowable weight of permit vehicle.
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RI Y SC Y BARS Y Y SD Y BARS Migrating to Virtis Y Y BARS TN Y Virtis, BARS In-house software Y Y Y In-house programs TX Y Risa3D STAAD-pro Y In-house software In-house software In-house software, BAR 7 UT VT In-house spreadsheets/programs In-house programs Not for a few years. VA Y STAAD Y pcBARS Y STAAD, Descus Mid-2005 WA BRIDG BRIDG WV Y Super load/ LARS LARS WI Y SIMON, in-house programs Girder line analysis SIMON in-house programs WY Y Y Summary Total responses 44 44 44 44 44 44 44 44 Yes 3 11 2 29 1 11 19 20 TABLE C4-5 (continued)
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From page 81... ...
LA ME MD MA Yes MI MN Yes MS Yes MO Yes MT Yes Yes TABLE C4-6 METHODS OF SCREENING PERMIT VEHICLES
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Remaining single trip permits are issued in our District and County offices, relying on charts and guidance from District Bridge Engineers. WI Yes WY Yes Summary Total responses 44 44 44 Yes 22 13 3 No response received if empty.
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From page 83... ...
KY Yes NBIS bridge inspection report Yes AASHTO MCEB LA ME MD MA Yes MassHighway Permit Vehicle Analysis Guidelines Yes MassHighway Bridge Load Rating Guidelines MI MN Yes AASHTO MCEB Yes AASHTO MCEB MS Yes AASHTO specs. Yes AASHTO specs.
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From page 84... ...
ND Yes AASHTO MCEB Yes Internal guidelines OH Yes AASHTO MCEB Yes ODOT Bridge Design Manual OK No. Just engineering judgment.
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From page 85... ...
No DC FL Yes. For very heavy trip permits (sometimes above 1000 kips)
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From page 86... ...
Use single lane distribution factor. If bridge fails, hand analysis to determine the distribution factor.
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From page 87... ...
No No PR No No No RI Yes. Only if the vehicle has a problem achieving permit status using load factor criteria, might the state consider passing the permit vehicle rating along to a consultant for a more in-depth review using wider axle widths.
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From page 88... ...
Yes. Only if a load rating is completed, and in rare situations.
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From page 89... ...
If Yes, How? Alberta Yes Yes When performing a bridge rating for a permit vehicle, each axle is modeled for its width, gage, and number of tires.
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MT Done the same as in the AASHTO Standard Specifications. Bearing center to center.
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From page 92... ...
Per AASHTO Standard Specifications. RI Typically the superimposed dead loads are distributed equally across all beams.
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Per AASHTO Standard Specifications. WI Varies Bearing center to center.
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From page 95... ...
AASHTO standard specs. AASHTO Guide Specifications Overlay dead loads, temporary barriers.
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AASHTO standard specs. Overlay dead loads, temporary barriers.
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Overlay dead loads, temporary barriers, all known dead loads are used. ND Moment AASHTO standard specs.
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From page 98... ...
No WI Moment AASHTO standard specs. Overlay dead loads.
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From page 99... ...
Overlay dead loads, temporary barriers. Toronto No response received if empty; CHBDC = Canadian Highway Bridge Design Code; CSA = Canadian Standards Association.
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From page 100... ...
State agency personnel. As noted, state performs analysis for standard permit vehicles (13 axle or less)
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From page 101... ...
NM Yes State agency personnel, local agency personnel, local agency-contracted consultants. State, local government.
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Who Decides Who Performs Rating for Local Bridges? VA Yes Local agency personnel, local agency-contracted consultants.
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Who Decides Who Performs Rating for Local Bridges? Alberta Yes Province agency personnel, local agency personnel, local agency-contracted consultants.
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From page 104... ...
AK Do you know of a Seminar for Load Rating Bridges according to AASHTO? AZ AR CA CO Additional contact: Mark Leonard, Staff Bridge Engineer CDOT, 303-757-309, mark.leonard@dot.state.co.us.
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From page 105... ...
NH NJ NM Uniformity of overloads in Southwest -- one meeting held March 2005, Las Vegas, NV. NY NC It is going to be very difficult to get consistency from state to state permit reviews for a variety of reasons, including posting policy, state laws for legal loads, rating methods that are used, no confidence in AASHTO Rating Specifications where the real world does not fit the specification results (e.g., Rating of Reinforced Concrete Members)
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From page 106... ...
TN My impression is that permit procedures and policies vary widely from state to state. There is little uniformity in the way permit vehicles are handled.
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From page 107... ...
Ottawa CHBDC, Section 14 -- Evaluation provides a standard used throughout Canada to rate existing bridges for overweight loads. PEI Quebec Toronto CHBDC = Canadian Highway Bridge Design Code.
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