B-WIM for Bridge Enforcement and Structural Safety

Department of Civil, Construction, and Environmental Engineering

UTCAUTCA

Objectives

• B-WIM system to control heavy vehicle overloads, to elaborate the suitable bridge types, and how to design instrumentation.

• B-WIM can reduce uncertainties in the traffic load assessment and optimize the allocation of available funding for bridge maintenance

• Freight planning purposes

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where:Q: predicted maximum live load effect, a-deterministic value relating the load effect to a reference loading scheme; W.95- characteristic vehicle weight; H-headway factor; m-factor reflecting the variations of load effects; I-impact factor; g-lateral distribution factor

The potential benefits …

Improved:

• delivery of enforcement services by enhancing effectiveness and efficiency;

• reduction in the total number of vehicle required to stop for enforcement purposes;

• emissions by reducing unnecessary deceleration, idling

• controlling of the operation of non-permitted, non-compliant (i.e., overweight or oversized) vehicles; and

• ongoing performance monitoring and evaluation of vehicle size and weight.

• freight planning

CET test – Luleå, SwedenJune 1997

Quarz sensor Bending plate SiWIM Piezo sensor0

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System

GVW Single axles Group axles

D+/C/C C/B/C B/B/C

BWIM shemaSiWIM Bridge

Weigh-in-motion

system

Modular build signal processing unitModular build signal processing unit

Advantages• Mobile• Very good accuracy• Quick installation• Reliable• No influence in the pavement• No road block• Low rate for maintenance• Price efficient • Specifications and traffic volume do not give satisfactory traffic

loads results• Bridge safety can be calculated more efficiently with SiWIM

system

Test Plan

• select the bridge

• install the system

• create the influence line

• calibration

• data processing for reports

• de-install the system

Calibration

Discusion

Results for each vehicle

• Axle load for individual axle

• Gross vehicle weight

• Axle distance

• Speed

• Class

• Exact time (2/1000 s)

• Temperature

Data can be used for

• traffic analyses and freight planning

• maintenance planning

• pre-selection for static weighing

• monitoring of overload vehicles trying to avoid static weighing session

• bridge applications (max. load...)

Maintenance sector and law enforcement

1. For critical road sections where overloading is a SERIOUS problem (quarries, sections under construction....)

9.8%

6.6%

83.6%

specifications SiWIM+legal SiWIM+overloaded

SiWIM for pre-selection

Bridge applications

• safety assessment of existing bridges• assessment of dynamic effects• aplication for special transport

Application for special transport

Evaluate bridge maintenance issues with the proposed bridge WIM system:

• Investigated to provide synchronized data on the traffic load effects and the induced stresses and strains, and therefore become a part of “Intelligent Bridge Monitoring Systems” to optimize the allocation of funds for bridge repair or replacement and to reduce the corresponding traffic disruption.

• Bridge WIM gives the essential information to calculate the realistic traffic loading Q, and allows for reducing the live load safety factor γQ, which both increase the safety of the structure.

*Process of collaboration is started with a French group of researchers who are working on multi-span and multilane bridge structures

**The information on the project including final report will be posted at (http://www.eng.uab.edu/cee/faculty/bwim/)

Bridge Weigh-in-Motion (B-WIM) Bridge Weigh-in-Motion (B-WIM) System Testing and EvaluationSystem Testing and Evaluation

• Eighteen Month Project• Multi-Campus Research Team • Diverse Project Advisory Group • PI: Dr. Wilbur (Bill) Hitchcock (UAB) • Co-PIs:

Dr. Nasim Uddin (UAB) Dr. Virginia Sisiopiku (UAB) Dr. Jason Kirby (UAB) Dr. Talat Abu-Amra (UAB) Dr. Jim Richardson (UA) Dr. Houssam Toutanji (UAH)