Overview ofBridge Inspections

in Missouri

David KoenigBridge Management Engineer

Missouri Department of Transportation

Missouri Bridge ConferenceApril 9, 2015Columbia, MO

Missouri Structure Totals

• 2014 National Bridge Inventory

• NBI Length Bridges (i.e. >20’ Length)

MoDOT—10,371

Local—13,977

Total—24,348

Map—MoDOT Structures

Structure Lengths

Longest

Local 5,731’ (McKinley-St. Louis)MoDOT 7,845’ (Double Decker-St.

Louis)

Distribution

>5000’—11 >4000’—24>3000’—43 >2000’—86>1000’—224 <300’—22,759

Average Local—69’MoDOT—196’ Statewide—123’

Posted Structures

MoDOT—1,367

Local—3,495

Total—4,862

Deficient Structures

Structural

1,058—MoDOT2,200—Local3,258—Total

Functional

908—MoDOT1,666—Local2,574—Total

Total Deficient

1,966—MoDOT3,866—Local5,832—Total

Inspections

Why do we do it?• Federal Law

• NBIS Regulations

• Public Safety

Inspections

• Failures—65% from Scour/Hydraulic issues

• Others from a widevariety of causes

Inspections

Types/Frequency (Defined by Federal Law)

General/Routine (24 months)

Special (Varies, 60 months max)

Fracture Critical (24 months)

Underwater (60 months)

In Depth (Per State Policy)

Qualifications (Federal Law)• Team Leader qualified person required on site

during all inspections

• Divers required to meet specific inspection training requirements

Inspections

General/Routine

• Majority of State/Local done by District Offices

• State ones that require special access equipment are done by Bridge Division out of Jefferson City

• Four local agencies do their own inspections with oversight by MoDOT

• Statewide around 70 people full/part time people are involved at a cost of $3 million per year

• Most done September thru March, but there are some going on year round

Inspections

Fracture Critical (950 Total)

MoDOT (235)—Bridge Division UBI Crews

Local (715)—Districts/Consultants Perform

Inspections

Underwater• Dives—163 (NBI)• Deep Wades—about 200 • Bridge Division/Consultants• Districts may Assist

Inspections

In Depth• Total—694

• Common Examples• Major Lake• Major River

• Others are for things hardto see from the ground, known problematic areas, and things that just need an occasional closer look

Example—Non FC Cantileverarea with crack. Repaired.

Inspections

Specials• Around 300 statewide• Typically done by UBI Crews• Occasionally Districts/Consultants

• Example—visual inspection found suspected crack. Dyepenetrant was used toto define extent. Pin mayhave had ultrasound done as well. Bridge was closedand later replaced.

Inspections

Element Level Inspections

• New MAP21 Requirement

• NHS Structures Only

• Started October 1, 2014

• 3,729 total NHS structures

• Have 800+ currently completed

• Minimum set of elements required to be collected and reported to FHWA

• MoDOT has chosen to only do the minimum that is required by MAP21

Inspections

Required Elements

• National Bridge Elements• Deck/Slab, Railings, Superstructure,

Substructure, Culverts, Bearings, Railings

• Bridge Management Elements

• Joints, Wearing Surface, Steel Protective Coating, Concrete Protective Coating

• Report Total Quantity for each Element

• Report Quantities for one of four Condition States CS1 (best), CS2, CS3, and CS4 (worst)

• Quantities—Square Feet, Linear Feet, Each